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Sample records for subject contrasts measured

  1. Using light scattering to measure the response of individual ultrasound contrast microbubbles subjected to pulsed ultrasound in vitro

    Science.gov (United States)

    Guan, Jingfeng; Matula, Thomas J.

    2004-11-01

    Light scattering was used to measure the radial pulsations of individual ultrasound contrast microbubbles subjected to pulsed ultrasound. Highly diluted Optison® or Sonazoid® microbubbles were injected into either a water bath or an aqueous solution containing small quantities of xanthan gum. Individual microbubbles were insonified by ultrasound pulses from either a commercial diagnostic ultrasound machine or a single element transducer. The instantaneous response curves of the microbubbles were measured. Linear and nonlinear microbubble oscillations were observed. Good agreement was obtained by fitting a bubble dynamics model to the data. The pulse-to-pulse evolution of individual microbubbles was investigated, the results of which suggest that the shell can be semipermeable, and possibly weaken with subsequent pulses. There is a high potential that light scattering can be used to optimize diagnostic ultrasound techniques, understand microbubble evolution, and obtain specific information about shell parameters. .

  2. The new numbers contrast sensitivity chart for contrast sensitivity measurement

    Directory of Open Access Journals (Sweden)

    Bharkbhum Khambhiphant

    2011-10-01

    Conclusions: These charts show reasonable agreement and can be used interchangeably with the MARS. It is helpful for Thai people who can only read numbers in doing the test. We can use them in routinely contrast sensitivity measurement.

  3. Reliability in perimetric multichannel contrast sensitivity measurements.

    Science.gov (United States)

    de Fez, Dolores; Capilla, Pascual; Camps, Vicente; Luque, M José; Moncho, Vicenta

    2014-11-01

    In this study, the reliability of perimetric contrast sensitivity measurements favouring the achromatic, the red-green and the blue-yellow post-receptorial mechanisms was analysed. A new technique, multichannel ATD perimetry, provides spatial and temporal stimuli favouring the detection by an achromatic mechanism (A), from a magno or parvocellular origin or by a red-green (RG) chromatic mechanism, with a parvocellular origin or a blue-yellow (BY) mechanism, with a koniocellular origin. The repeatability and reproducibility of contrast sensitivity measurements with these stimuli were studied in a group of 40 healthy subjects. The analysis was carried out on 21 testing points within a 60° by 40° fovea-centred region of the visual field. The within-observer repeatability for the four mechanisms studied is either good or excellent when the intra-class correlation coefficient (ICC) can be calculated. For the remaining points, the Friedman's test finds that the measurements are repeatable. The between-observer reproducibility was either excellent or good in cases where the ICC was applied and according to the Friedman's test all results were reproducible. The results obtained showed good repeatability and reproducibility with A, RG and BY stimuli, although with BY stimuli repeatability is slightly worse. Future studies on the diagnostic validity of this device are based on the fact that changes of sensitivity can be compared by means of a visual single task, contrast sensitivity measurement and using a common metric. © 2014 The Authors. Clinical and Experimental Optometry © 2014 Optometrists Association Australia.

  4. [Reproducibility of subjective refraction measurement].

    Science.gov (United States)

    Grein, H-J; Schmidt, O; Ritsche, A

    2014-11-01

    Reproducibility of subjective refraction measurement is limited by various factors. The main factors affecting reproducibility include the characteristics of the measurement method and of the subject and the examiner. This article presents the results of a study on this topic, focusing on the reproducibility of subjective refraction measurement in healthy eyes. The results of previous studies are not all presented in the same way by the respective authors and cannot be fully standardized without consulting the original scientific data. To the extent that they are comparable, the results of our study largely correspond largely with those of previous investigations: During repeated subjective refraction measurement, 95% of the deviation from the mean value was approximately ±0.2 D to ±0.65 D for the spherical equivalent and cylindrical power. The reproducibility of subjective refraction measurement in healthy eyes is limited, even under ideal conditions. Correct assessment of refraction results is only feasible after identifying individual variability. Several measurements are required. Refraction cannot be measured without a tolerance range. The English full-text version of this article is available at SpringerLink (under supplemental).

  5. Investigating the visual inspection subjectivity on the contrast-detail evaluation in digital mammography images

    Science.gov (United States)

    Sousa, Maria A. Z.; Medeiros, Regina B.; Schiabel, Homero

    2014-03-01

    A major difficulty in the interpretation of mammographic images is the low contrast and, in the case of early detection of breast cancer, the reduced size of the features of malignancy on findings such as microcalcifications. Furthermore, image assessment is subject to significant reliance of the capacity of observation of the expert that will perform it, compromising the final diagnosis accuracy. Thinking about this aspect, this study evaluated the subjectivity of visual inspection to assess the contrast-detail in mammographic images. For this, we compared the human readings of images generated with the CDMAM phantom performed by four observers, enabling to determining a threshold of contrast visibility in each diameter disks present in the phantom. These thresholds were compared graphically and by statistical measures allowing us to build a strategy for use of contrast and detail (dimensions) as parameters of quality in mammography.

  6. Mercury toxicity in the Amazon: contrast sensitivity and color discrimination of subjects exposed to mercury

    Directory of Open Access Journals (Sweden)

    A.R. Rodrigues

    2007-03-01

    Full Text Available We measured visual performance in achromatic and chromatic spatial tasks of mercury-exposed subjects and compared the results with norms obtained from healthy individuals of similar age. Data were obtained for a group of 28 mercury-exposed subjects, comprising 20 Amazonian gold miners, 2 inhabitants of Amazonian riverside communities, and 6 laboratory technicians, who asked for medical care. Statistical norms were generated by testing healthy control subjects divided into three age groups. The performance of a substantial proportion of the mercury-exposed subjects was below the norms in all of these tasks. Eleven of 20 subjects (55% performed below the norms in the achromatic contrast sensitivity task. The mercury-exposed subjects also had lower red-green contrast sensitivity deficits at all tested spatial frequencies (9/11 subjects; 81%. Three gold miners and 1 riverine (4/19 subjects, 21% performed worse than normal subjects making more mistakes in the color arrangement test. Five of 10 subjects tested (50%, comprising 2 gold miners, 2 technicians, and 1 riverine, performed worse than normal in the color discrimination test, having areas of one or more MacAdam ellipse larger than normal subjects and high color discrimination thresholds at least in one color locus. These data indicate that psychophysical assessment can be used to quantify the degree of visual impairment of mercury-exposed subjects. They also suggest that some spatial tests such as the measurement of red-green chromatic contrast are sufficiently sensitive to detect visual dysfunction caused by mercury toxicity.

  7. Human cerebral blood volume measurements using dynamic contrast enhancement in comparison to dynamic susceptibility contrast MRI

    Energy Technology Data Exchange (ETDEWEB)

    Artzi, Moran [Tel Aviv Sourasky Medical Center, Functional Brain Center, The Wohl Institute for Advanced Imaging, Tel Aviv (Israel); Tel Aviv University, Sackler Faculty of Medicine, Tel Aviv (Israel); Liberman, Gilad; Vitinshtein, Faina; Aizenstein, Orna [Tel Aviv Sourasky Medical Center, Functional Brain Center, The Wohl Institute for Advanced Imaging, Tel Aviv (Israel); Nadav, Guy [Tel Aviv Sourasky Medical Center, Functional Brain Center, The Wohl Institute for Advanced Imaging, Tel Aviv (Israel); Tel Aviv University, Faculty of Engineering, Tel Aviv (Israel); Blumenthal, Deborah T.; Bokstein, Felix [Tel Aviv Sourasky Medical Center, Neuro-Oncology Service, Tel Aviv (Israel); Bashat, Dafna Ben [Tel Aviv Sourasky Medical Center, Functional Brain Center, The Wohl Institute for Advanced Imaging, Tel Aviv (Israel); Tel Aviv University, Sackler Faculty of Medicine and Sagol School of Neuroscience, Tel Aviv (Israel)

    2015-07-15

    Cerebral blood volume (CBV) is an important parameter for the assessment of brain tumors, usually obtained using dynamic susceptibility contrast (DSC) MRI. However, this method often suffers from low spatial resolution and high sensitivity to susceptibility artifacts and usually does not take into account the effect of tissue permeability. The plasma volume (v{sub p}) can also be extracted from dynamic contrast enhancement (DCE) MRI. The aim of this study was to investigate whether DCE can be used for the measurement of cerebral blood volume in place of DSC for the assessment of patients with brain tumors. Twenty-eight subjects (17 healthy subjects and 11 patients with glioblastoma) were scanned using DCE and DSC. v{sub p} and CBV values were measured and compared in different brain components in healthy subjects and in the tumor area in patients. Significant high correlations were detected between v{sub p} and CBV in healthy subjects in the different brain components; white matter, gray matter, and arteries, correlating with the known increased tissue vascularity, and within the tumor area in patients. This work proposes the use of DCE as an alternative method to DSC for the assessment of blood volume, given the advantages of its higher spatial resolution, its lower sensitivity to susceptibility artifacts, and its ability to provide additional information regarding tissue permeability. (orig.)

  8. Modeling the subjective quality of highly contrasted videos displayed on LCD with local backlight dimming.

    Science.gov (United States)

    Mantel, Claire; Bech, Søren; Korhonen, Jari; Forchhammer, Søren; Pedersen, Jesper Melgaard

    2015-02-01

    Local backlight dimming is a technology aiming at both saving energy and improving visual quality on television sets. As the rendition of the image is specified locally, the numerical signal corresponding to the displayed image needs to be computed through a model of the display. This simulated signal can then be used as input to objective quality metrics. The focus of this paper is on determining which characteristics of locally backlit displays influence quality assessment. A subjective experiment assessing the quality of highly contrasted videos displayed with various local backlight-dimming algorithms is set up. Subjective results are then compared with both objective measures and objective quality metrics using different display models. The first analysis indicates that the most significant objective features are temporal variations, power consumption (probably representing leakage), and a contrast measure. The second analysis shows that modeling of leakage is necessary for objective quality assessment of sequences displayed with local backlight dimming.

  9. Change Blindness Is Influenced by Both Contrast Energy and Subjective Importance within Local Regions of the Image.

    Science.gov (United States)

    Zuiderbaan, Wietske; van Leeuwen, Jonathan; Dumoulin, Serge O

    2017-01-01

    Our visual system receives an enormous amount of information, but not all information is retained. This is exemplified by the fact that subjects fail to detect large changes in a visual scene, i.e., change-blindness. Current theories propose that our ability to detect these changes is influenced by the gist or interpretation of an image. On the other hand, stimulus-driven image features such as contrast energy dominate the representation in early visual cortex (De Valois and De Valois, 1988; Boynton et al., 1999; Olman et al., 2004; Mante and Carandini, 2005; Dumoulin et al., 2008). Here we investigated whether contrast energy contributes to our ability to detect changes within a visual scene. We compared the ability to detect changes in contrast energy together with changes to a measure of the interpretation of an image. We used subjective important aspects of the image as a measure of the interpretation of an image. We measured reaction times while manipulating the contrast energy and subjective important properties using the change blindness paradigm. Our results suggest that our ability to detect changes in a visual scene is not only influenced by the subjective importance, but also by contrast energy. Also, we find that contrast energy and subjective importance interact. We speculate that contrast energy and subjective important properties are not independently represented in the visual system. Thus, our results suggest that the information that is retained of a visual scene is both influenced by stimulus-driven information as well as the interpretation of a scene.

  10. Change Blindness Is Influenced by Both Contrast Energy and Subjective Importance within Local Regions of the Image

    Directory of Open Access Journals (Sweden)

    Wietske Zuiderbaan

    2017-10-01

    Full Text Available Our visual system receives an enormous amount of information, but not all information is retained. This is exemplified by the fact that subjects fail to detect large changes in a visual scene, i.e., change-blindness. Current theories propose that our ability to detect these changes is influenced by the gist or interpretation of an image. On the other hand, stimulus-driven image features such as contrast energy dominate the representation in early visual cortex (De Valois and De Valois, 1988; Boynton et al., 1999; Olman et al., 2004; Mante and Carandini, 2005; Dumoulin et al., 2008. Here we investigated whether contrast energy contributes to our ability to detect changes within a visual scene. We compared the ability to detect changes in contrast energy together with changes to a measure of the interpretation of an image. We used subjective important aspects of the image as a measure of the interpretation of an image. We measured reaction times while manipulating the contrast energy and subjective important properties using the change blindness paradigm. Our results suggest that our ability to detect changes in a visual scene is not only influenced by the subjective importance, but also by contrast energy. Also, we find that contrast energy and subjective importance interact. We speculate that contrast energy and subjective important properties are not independently represented in the visual system. Thus, our results suggest that the information that is retained of a visual scene is both influenced by stimulus-driven information as well as the interpretation of a scene.

  11. Generation And Measurement Of High Contrast Ultrashort Intense Laser Pulses

    CERN Document Server

    Konoplev, O A

    2000-01-01

    In this thesis, the generation and measurement of high contrast, intense, ultrashort pulses have been studied. Various factors affecting the contrast and pulse shape of ultrashort light pulses from a chirped pulse amplification (CPA) laser system are identified. The level of contrast resulting from influence of these factors is estimated. Methods for improving and controlling the pulse shape and increasing the contrast are discussed. Ultrahigh contrast, 1-ps pulses were generated from a CPA system with no temporal structure up to eleven orders of magnitude. This is eight orders of magnitude higher contrast than the original pulse. This contrast boost was achieved using two techniques. One is the optical pulse cleaning based on the nonlinear birefringence of the chirping fiber and applied to the pulses before amplification. The other is the fast saturable absorber. The fast saturable absorber was placed after amplification and compression of the pulse. The measurements of high-contrast, ultrashort pulse with h...

  12. Subjective measures of well--being

    NARCIS (Netherlands)

    R. Veenhoven (Ruut)

    2007-01-01

    textabstractThis chapter deals with three question: 1) What are ‘subjective’ measure? 2) What is ‘wellbeing’? and 3) Are subjective measures of wellbeing of use for policymaking, in particular in developing nations? The first question is answered by making a distinction between two kinds of

  13. Modeling the Subjective Quality of Highly Contrasted Videos Displayed on LCD With Local Backlight Dimming

    DEFF Research Database (Denmark)

    Mantel, Claire; Bech, Søren; Korhonen, Jari

    2015-01-01

    signal can then be used as input to objective quality metrics. The focus of this paper is on determining which characteristics of locally backlit displays influence quality assessment. A subjective experiment assessing the quality of highly contrasted videos displayed with various local backlight...

  14. Measuring the acoustophoretic contrast factor of living cells in microchannels

    DEFF Research Database (Denmark)

    Augustsson, P.; Barnkob, Rune; Grenvall, C.

    2010-01-01

    We report a new method, which allows for accurate measurement of the acostophoretic contrast factor Φ of different cell types, an acousto-physical parameter of fundamental importance in microchip acoustophoresis. As a test case the Φ factor is measured for undifferentiated and four-days different......We report a new method, which allows for accurate measurement of the acostophoretic contrast factor Φ of different cell types, an acousto-physical parameter of fundamental importance in microchip acoustophoresis. As a test case the Φ factor is measured for undifferentiated and four...

  15. Measuring and Estimating Normalized Contrast in Infrared Flash Thermography

    Science.gov (United States)

    Koshti, Ajay M.

    2013-01-01

    Infrared flash thermography (IRFT) is used to detect void-like flaws in a test object. The IRFT technique involves heating up the part surface using a flash of flash lamps. The post-flash evolution of the part surface temperature is sensed by an IR camera in terms of pixel intensity of image pixels. The IR technique involves recording of the IR video image data and analysis of the data using the normalized pixel intensity and temperature contrast analysis method for characterization of void-like flaws for depth and width. This work introduces a new definition of the normalized IR pixel intensity contrast and normalized surface temperature contrast. A procedure is provided to compute the pixel intensity contrast from the camera pixel intensity evolution data. The pixel intensity contrast and the corresponding surface temperature contrast differ but are related. This work provides a method to estimate the temperature evolution and the normalized temperature contrast from the measured pixel intensity evolution data and some additional measurements during data acquisition.

  16. Appropriate Contrast Enhancement Measures for Brain and Breast Cancer Images

    OpenAIRE

    Suneet Gupta; Rabins Porwal

    2016-01-01

    Medical imaging systems often produce images that require enhancement, such as improving the image contrast as they are poor in contrast. Therefore, they must be enhanced before they are examined by medical professionals. This is necessary for proper diagnosis and subsequent treatment. We do have various enhancement algorithms which enhance the medical images to different extents. We also have various quantitative metrics or measures which evaluate the quality of an image. This paper suggests...

  17. Rupture threshold characterization of polymer-shelled ultrasound contrast agents subjected to static overpressure

    Science.gov (United States)

    Chitnis, Parag V.; Lee, Paul; Mamou, Jonathan; Allen, John S.; Böhmer, Marcel; Ketterling, Jeffrey A.

    2011-04-01

    Polymer-shelled micro-bubbles are employed as ultrasound contrast agents (UCAs) and vesicles for targeted drug delivery. UCA-based delivery of the therapeutic payload relies on ultrasound-induced shell rupture. The fragility of two polymer-shelled UCAs manufactured by Point Biomedical or Philips Research was investigated by characterizing their response to static overpressure. The nominal diameters of Point and Philips UCAs were 3 μm and 2 μm, respectively. The UCAs were subjected to static overpressure in a glycerol-filled test chamber with a microscope-reticule lid. UCAs were reconstituted in 0.1 mL of water and added over the glycerol surface in contact with the reticule. A video-microscope imaged UCAs as glycerol was injected (5 mL/h) to vary the pressure from 2 to 180 kPa over 1 h. Neither UCA population responded to overpressure until the rupture threshold was exceeded, which resulted in abrupt destruction. The rupture data for both UCAs indicated three subclasses that exhibited different rupture behavior, although their mean diameters were not statistically different. The rupture pressures provided a measure of UCA fragility; the Philips UCAs were more resilient than Point UCAs. Results were compared to theoretical models of spherical shells under compression. Observed variations in rupture pressures are attributed to shell imperfections. These results may provide means to optimize polymeric UCAs for drug delivery and elucidate associated mechanisms.

  18. Appropriate Contrast Enhancement Measures for Brain and Breast Cancer Images.

    Science.gov (United States)

    Gupta, Suneet; Porwal, Rabins

    2016-01-01

    Medical imaging systems often produce images that require enhancement, such as improving the image contrast as they are poor in contrast. Therefore, they must be enhanced before they are examined by medical professionals. This is necessary for proper diagnosis and subsequent treatment. We do have various enhancement algorithms which enhance the medical images to different extents. We also have various quantitative metrics or measures which evaluate the quality of an image. This paper suggests the most appropriate measures for two of the medical images, namely, brain cancer images and breast cancer images.

  19. Appropriate Contrast Enhancement Measures for Brain and Breast Cancer Images

    Directory of Open Access Journals (Sweden)

    Suneet Gupta

    2016-01-01

    Full Text Available Medical imaging systems often produce images that require enhancement, such as improving the image contrast as they are poor in contrast. Therefore, they must be enhanced before they are examined by medical professionals. This is necessary for proper diagnosis and subsequent treatment. We do have various enhancement algorithms which enhance the medical images to different extents. We also have various quantitative metrics or measures which evaluate the quality of an image. This paper suggests the most appropriate measures for two of the medical images, namely, brain cancer images and breast cancer images.

  20. CONTRAST

    DEFF Research Database (Denmark)

    Kristensen, Thomas Krogsgaard

    2007-01-01

    Dette er en afrapportering fra den årlige CONTRAST workshop, der i 2007 blev afholdt i Yaoundé, Cameroon.......Dette er en afrapportering fra den årlige CONTRAST workshop, der i 2007 blev afholdt i Yaoundé, Cameroon....

  1. Suitability of new anode materials in mammography: dose and subject contrast considerations using Monte Carlo simulation.

    Science.gov (United States)

    Delis, H; Spyrou, G; Costaridou, L; Tzanakos, G; Panayiotakis, G

    2006-11-01

    Mammography is the technique with the highest sensitivity and specificity, for the early detection of nonpalpable lesions associated with breast cancer. As screening mammography refers to asymptomatic women, the task of optimization between the image quality and the radiation dose is critical. A way toward optimization could be the introduction of new anode materials. A method for producing the x-ray spectra of different anode/filter combinations is proposed. The performance of several mammographic spectra, produced by both existing and theoretical anode materials, is evaluated, with respect to their dose and subject contrast characteristics, using a Monte Carlo simulation. The mammographic performance is evaluated utilizing a properly designed mathematical phantom with embedded inhomogeneities, irradiated with different spectra, based on combinations of conventional and new (Ru, Ag) anode materials, with several filters (Mo, Rh, Ru, Ag, Nb, Al). An earlier developed and validated Monte Carlo model, for deriving both image and dose characteristics in mammography, was utilized and overall performance results were derived in terms of subject contrast to dose ratio and squared subject contrast to dose ratio. Results demonstrate that soft spectra, mainly produced from Mo, Rh, and Ru anodes and filtered with k-edge filters, provide increased subject contrast for inhomogeneities of both small size, simulating microcalcifications and low density, simulating masses. The harder spectra (W and Ag anode) come short in the discrimination task but demonstrate improved performance when considering the dose delivered to the breast tissue. As far as the overall performance is concerned, new theoretical spectra demonstrate a noticeable good performance that is similar, and in some cases better compared to commonly used systems, stressing the possibility of introducing new materials in mammographic practice as a possible contribution to its optimization task. In the overall

  2. [Measurement of contrast vision: mesopic or photopic vision? : Comparison of different methods for measuring contrast sensitivity within the framework of driving licence regulations].

    Science.gov (United States)

    Bergmann, L C E; Darius, S; Kropf, S; Böckelmann, I

    2016-10-01

    Since 2011 the regulations for occupational driving licences make the examination of contrast vision sensitivity obligatory; however, apart from mesopic procedures no uniform regulations are available for methods and minimum requirements. By comparing different mesopic and photopic contrast sensitivity tests this study analyzed whether these could be equivalently used and lead to the same results. Contrast vision sensitivity was determined in 150 subjects with emmetropia using five different methods, i.e. the mesopic test device Mesotest II as the reference method, Rodatest 302 and Optovist as photopic test devices and two photopic test charts (Vistech chart and Mars charts). The results of passing the tests were compared and Cohens κ was determined to quantify the conformity between the tests. Poor agreement was found between Mesotest II and Optovist as well as between Mesotest II and the Vistech chart. There was no agreement between Rodatest 302 or Mars charts and Mesotest II; nevertheless, the contrast vision sensitivity measured with Optovist, Rodatest 302 and the Vistech chart showed good correlation (0.46 ≤ r ≤ 0.69). Apart from a few limitations, the reference method Mesotest II as well as Optovist and the Vistech chart are suitable for testing contrast vision sensitivity, whereas Rodatest 302 and Mars charts cannot be recommended based on the current criteria for minimum requirements. The minimum requirements must be urgently adapted and strict regulations for measurement must be formulated. In addition, due to the poor agreement between the methods an amendment of the driving licence regulations should be considered, which requires examination of both mesopic and photopic contrast vision or alternatively mesopic contrast vision alone.

  3. The Validity of Subjective Performance Measures

    DEFF Research Database (Denmark)

    Meier, Kenneth J.; Winter, Søren C.; O'Toole, Laurence J.

    2015-01-01

    Public management studies are increasingly using survey data on managers’ perceptions of performance to measure organizational performance. The perceptual measures are tempting to apply because archival performance data or surveys of target group outcomes and satisfaction are often lacking, costly...... to provide, and are highly policy specific rendering generalization difficult. But are perceptual performance measures valid, and do they generate unbiased findings? We examine these questions in a comparative study of middle managers in schools in Texas and Denmark. The findings are remarkably similar...... the resources it has. Even worse, the use of perceptual performance measures seems to provide biased estimates when examining how management affects performance....

  4. Optimizing preprocessing and analysis pipelines for single-subject fMRI: 2. Interactions with ICA, PCA, task contrast and inter-subject heterogeneity.

    Science.gov (United States)

    Churchill, Nathan W; Yourganov, Grigori; Oder, Anita; Tam, Fred; Graham, Simon J; Strother, Stephen C

    2012-01-01

    A variety of preprocessing techniques are available to correct subject-dependant artifacts in fMRI, caused by head motion and physiological noise. Although it has been established that the chosen preprocessing steps (or "pipeline") may significantly affect fMRI results, it is not well understood how preprocessing choices interact with other parts of the fMRI experimental design. In this study, we examine how two experimental factors interact with preprocessing: between-subject heterogeneity, and strength of task contrast. Two levels of cognitive contrast were examined in an fMRI adaptation of the Trail-Making Test, with data from young, healthy adults. The importance of standard preprocessing with motion correction, physiological noise correction, motion parameter regression and temporal detrending were examined for the two task contrasts. We also tested subspace estimation using Principal Component Analysis (PCA), and Independent Component Analysis (ICA). Results were obtained for Penalized Discriminant Analysis, and model performance quantified with reproducibility (R) and prediction metrics (P). Simulation methods were also used to test for potential biases from individual-subject optimization. Our results demonstrate that (1) individual pipeline optimization is not significantly more biased than fixed preprocessing. In addition, (2) when applying a fixed pipeline across all subjects, the task contrast significantly affects pipeline performance; in particular, the effects of PCA and ICA models vary with contrast, and are not by themselves optimal preprocessing steps. Also, (3) selecting the optimal pipeline for each subject improves within-subject (P,R) and between-subject overlap, with the weaker cognitive contrast being more sensitive to pipeline optimization. These results demonstrate that sensitivity of fMRI results is influenced not only by preprocessing choices, but also by interactions with other experimental design factors. This paper outlines a

  5. Associations of objectively and subjectively measured physical ...

    African Journals Online (AJOL)

    PBSSs) calculated from physical activity (PA) questionnaires and accelerometry measures of PA with trabecular and cortical bone properties in prepubertal children. Methods. We compared PBSSs calculated from the bone-specific component of PA ...

  6. Subjective contrast sensitivity function assessment in stereoscopic viewing of Gabor patches

    Science.gov (United States)

    Rousson, Johanna; Haar, Jérémy; Platiša, Ljiljana; Piepers, Bastian; Kimpe, Tom R.; Philips, Wilfried

    2015-03-01

    While 3D displays are entering hospitals, no study to-date has explored the impact of binocular disparity and 3D inclination on contrast sensitivity function (CSF) of humans. However, knowledge of the CSF is crucial to properly calibrate medical, especially diagnostic, displays. This study examined the impact of two parameters on the CSF: (1) the depth plane position (0 mm or 171 mm behind the display plane, respectively DP:0 or DP:171), and (2) the 3D inclination (0° or 45° around the horizontal axis of the considered DP), each of these for seven spatial frequencies ranging from 0.4 to 10 cycles per degree (cpd). The stimuli were computer-generated stereoscopic images of a vertically oriented 2D Gabor patch with a given frequency. They were displayed on a 24" full HD stereoscopic display using a patterned retarder. Nine human observers assessed the CSF in a 3-down 1-up staircase experiment. Medians of the measured contrast sensitivities and results of Friedman tests suggest that the 2D CSF as modeled by Barten1 still holds when a 3D display is used as a 2D visualization system (DP:0). However, the 3D CSF measured at DP:171 was found different from the 2D CSF at frequencies below 1 cpd and above 10 cpd.

  7. Subjective Optic Disc Assessment and Single Measurement ...

    African Journals Online (AJOL)

    Verbal consent was obtained from the Treasury Department of the Rivers State Ministry of Finance and also from all individuals who participated in the study. Demographic data including age and sex were recorded in the WHO/PBL eye examination form. Ocular examination consisted of uncorrected VA measured with ...

  8. Nephron blood flow dynamics measured by laser speckle contrast imaging

    DEFF Research Database (Denmark)

    von Holstein-Rathlou, Niels-Henrik; Sosnovtseva, Olga V; Pavlov, Alexey N

    2011-01-01

    Tubuloglomerular feedback (TGF) has an important role in autoregulation of renal blood flow and glomerular filtration rate (GFR). Because of the characteristics of signal transmission in the feedback loop, the TGF undergoes self-sustained oscillations in single-nephron blood flow, GFR, and tubular...... pressure and flow. Nephrons interact by exchanging electrical signals conducted electrotonically through cells of the vascular wall, leading to synchronization of the TGF-mediated oscillations. Experimental studies of these interactions have been limited to observations on two or at most three nephrons...... simultaneously. The interacting nephron fields are likely to be more extensive. We have turned to laser speckle contrast imaging to measure the blood flow dynamics of 50-100 nephrons simultaneously on the renal surface of anesthetized rats. We report the application of this method and describe analytic...

  9. Similar and contrasting dimensions of social cognition in schizophrenia and healthy subjects.

    Science.gov (United States)

    Mehta, Urvakhsh Meherwan; Thirthalli, Jagadisha; Bhagyavathi, H D; Keshav Kumar, J; Subbakrishna, D K; Gangadhar, Bangalore N; Eack, Shaun M; Keshavan, Matcheri S

    2014-08-01

    Schizophrenia patients experience substantial impairments in social cognition (SC) and these deficits are associated with their poor functional outcome. Though SC is consistently shown to emerge as a cognitive dimension distinct from neurocognition, the dimensionality of SC is poorly understood. Moreover, comparing the components of SC between schizophrenia patients and healthy comparison subjects would provide specific insights on the construct validity of SC. We conducted principal component analyses of eight SC test scores (representing four domains of SC, namely, theory of mind, emotion processing, social perception and attributional bias) independently in 170 remitted schizophrenia patients and 111 matched healthy comparison subjects. We also conducted regression analyses to evaluate the relative contribution of individual SC components to other symptom dimensions, which are important clinical determinants of functional outcome (i.e., neurocognition, negative symptoms, motivational deficits and insight) in schizophrenia. A three-factor solution representing socio-emotional processing, social-inferential ability and external attribution components emerged in the patient group that accounted for 64.43% of the variance. In contrast, a two-factor solution representing socio-emotional processing and social-inferential ability was derived in the healthy comparison group that explained 56.5% of the variance. In the patient group, the social-inferential component predicted negative symptoms and motivational deficits. Our results suggest the presence of a multidimensional SC construct. The dimensionality of SC observed across the two groups, though not identical, displayed important parallels. Individual components also demonstrated distinct patterns of association with other symptom dimensions, thus supporting their external validity. Copyright © 2014 Elsevier B.V. All rights reserved.

  10. Spatial luminance contrast sensitivity measured with transient VEP: comparison with psychophysics and evidence of multiple mechanisms.

    Science.gov (United States)

    Souza, Givago S; Gomes, Bruno D; Saito, Cézar A; da Silva Filho, Manoel; Silveira, Luiz Carlos L

    2007-07-01

    To compare the spatial luminance contrast sensitivity function (CSF) obtained with transient visual evoked potentials (VEPs) with that obtained with psychophysical measurements. The stimuli consisted of horizontal luminance gratings. In the VEP experiments, 0.4, 0.8, 2, 4, 8, and 10 cpd of spatial frequency were used, at 1 Hz square-wave contrast-reversal mode. Eight to 10 Michelson contrasts were used at each spatial frequency. Contrast thresholds were estimated from extrapolation of contrast response functions. Psychophysical sensitivities were obtained with spatial gratings of 0.4, 0.8, 1, 2, 4, 6, 8, and 10 cpd and presented at 1 Hz square-wave contrast-reversal or stationary mode (dynamic and static presentation, respectively). CSF tuning was estimated by calculating the ratio between peak sensitivity and the sensitivity at 0.4 cpd. In all subjects tested (n = 6), VEP contrast-response functions showed nonlinearities-namely, amplitude saturation and double-slope amplitude functions that occurred at low and medium-to-high spatial frequencies, respectively. Mean electrophysiological and psychophysical CSFs peaked at 2 cpd. CSF tuning for electrophysiology and dynamic and static psychophysics were, respectively, 1.08, 1.11, and 1.31. Correlation coefficients (r(2)) between electrophysiological CSF and dynamic or static psychophysical CSF were, respectively, 0.81 and 0.45. Electrophysiological and psychophysical CSFs correlated more positively when temporal presentation was similar. Spatial frequencies higher than 2 cpd showed that at least two visual pathways sum their activities at high contrasts. At low contrast levels, the results suggest that the transient VEP is dominated by the magnocellular (M) pathway.

  11. Reproducibility of single-subject functional connectivity measurements

    National Research Council Canada - National Science Library

    Anderson, J S; Ferguson, M A; Lopez-Larson, M; Yurgelun-Todd, D

    2011-01-01

    .... We collected data to characterize how much imaging time is necessary to obtain reproducible quantitative functional connectivity measurements needed for a reliable single-subject diagnostic test...

  12. [Guideline 'Precautionary measures for contrast media containing iodine'

    NARCIS (Netherlands)

    Dijk Azn, R. van; Wetzels, J.F.M.; Dam, MA ten; Aarts, N.J.; Schimmelpenninck-Scheiffers, M.L.; Freericks, M.P.; Said, S.A.M.; Geenen, R.W.; Stuurman, A.; Everdingen, J.J. van

    2008-01-01

    Annually, 0.5-1 million injections of contrast media containing iodine are administered in the Netherlands. Almost all contrast media nowadays are low-osmolar and nonionic. Nevertheless, the development ofcontrast-induced nephropathy is still a relevant clinical problem. Through an initiative by the

  13. Driver contrast sensitivity and reaction times as measured through a salt-covered windshield.

    Science.gov (United States)

    Bachman, W Gary; Wingert, Timothy A; Bassi, Carl J

    2006-02-01

    The objective of this study was to use contrast sensitivity measurements to determine the effect of windshield salt film on driver vision. This effect simulates road salt spray that dries in place on a vehicle windshield during winter driving conditions. Ten emmetropic subjects were tested to assess contrast sensitivity functions through windshields that were clear compared with the same stimuli as viewed through windshields coated with salt film. Achromatic stimuli were generated by a VisionWorks system and were presented at 4 spatial frequencies (0.5, 3, 10, and 20 cycles per degree). A significant reduction in contrast sensitivity through the salt film was found at all spatial frequencies. In addition, reaction time to detect the stimuli was also found to be increased significantly at 2 of the 4 spatial frequencies through the saline-covered windshield. The results of this study indicate that windshield salt film reduces the ability to detect high and low contrast objects in a simulated driving environment as well as increases the subjects' reaction times.

  14. Comparing subjective and objective measures of headgear compliance.

    Science.gov (United States)

    Bos, Annemieke; Kleverlaan, Cornelis J; Hoogstraten, Johan; Prahl-Andersen, Birte; Kuitert, Rein

    2007-12-01

    Many studies have used subjective measures to examine patient compliance during orthodontic treatment. Objective measurement of compliance has been confined to only a few studies that used electronic timing devices built into removable appliances. Our aim in this study was to compare subjective and objective methods of measuring compliance with headgear wear. It was hypothesized that orthodontists, patients, and patients' parents overestimate compliance and report more wearing hours than the headgear timers indicate. Also, relationships between sex, age, treatment time, and headgear compliance were explored. A headgear timer device and 3 questionnaires were developed to assess compliance. The subjects were unaware that their headgear use was being measured. Significant differences between the estimates of orthodontists, patients, parents, and headgear timer scores were found. Also, there were differences regarding age and treatment time. Subjective measures might result in overestimation of compliance. This suggests that the use of an objective instrument to measure headgear compliance should be continued in future studies.

  15. Methods and Systems for Measurement and Estimation of Normalized Contrast in Infrared Thermography

    Science.gov (United States)

    Koshti, Ajay M. (Inventor)

    2015-01-01

    Methods and systems for converting an image contrast evolution of an object to a temperature contrast evolution and vice versa are disclosed, including methods for assessing an emissivity of the object; calculating an afterglow heat flux evolution; calculating a measurement region of interest temperature change; calculating a reference region of interest temperature change; calculating a reflection temperature change; calculating the image contrast evolution or the temperature contrast evolution; and converting the image contrast evolution to the temperature contrast evolution or vice versa, respectively.

  16. Methods and Systems for Measurement and Estimation of Normalized Contrast in Infrared Thermography

    Science.gov (United States)

    Koshti, Ajay M. (Inventor)

    2017-01-01

    Methods and systems for converting an image contrast evolution of an object to a temperature contrast evolution and vice versa are disclosed, including methods for assessing an emissivity of the object; calculating an afterglow heat flux evolution; calculating a measurement region of interest temperature change; calculating a reference region of interest temperature change; calculating a reflection temperature change; calculating the image contrast evolution or the temperature contrast evolution; and converting the image contrast evolution to the temperature contrast evolution or vice versa, respectively.

  17. Cultural influences on the measurement of subjective mental workload

    NARCIS (Netherlands)

    Johnson, Addie; Widyanti, Ari

    2011-01-01

    Cognitive ergonomics is well entrenched in North American and most European work environments, where systems and products are designed with the capabilities and limitations of the user in mind. A prominent technique for analysing task demands is subjective mental workload measurement. Subjective

  18. Human visual system-based image enhancement and logarithmic contrast measure.

    Science.gov (United States)

    Panetta, Karen A; Wharton, Eric J; Agaian, Sos S

    2008-02-01

    Varying scene illumination poses many challenging problems for machine vision systems. One such issue is developing global enhancement methods that work effectively across the varying illumination. In this paper, we introduce two novel image enhancement algorithms: edge-preserving contrast enhancement, which is able to better preserve edge details while enhancing contrast in images with varying illumination, and a novel multihistogram equalization method which utilizes the human visual system (HVS) to segment the image, allowing a fast and efficient correction of nonuniform illumination. We then extend this HVS-based multihistogram equalization approach to create a general enhancement method that can utilize any combination of enhancement algorithms for an improved performance. Additionally, we propose new quantitative measures of image enhancement, called the logarithmic Michelson contrast measure (AME) and the logarithmic AME by entropy. Many image enhancement methods require selection of operating parameters, which are typically chosen using subjective methods, but these new measures allow for automated selection. We present experimental results for these methods and make a comparison against other leading algorithms.

  19. Measuring human wellbeing in Pakistan: objective versus subjective indicators

    OpenAIRE

    Haq, Rashida

    2009-01-01

    The concern for measuring wellbeing objectively and subjectively is found in modern political philosophy. This study explores objective indicators versus subjective perceptions of human wellbeing in ranking of survey data for districts of Pakistan. Data used for the analysis is ‘The Pakistan Social and Living Standards Measurement Survey’ for the year 2006-07. The human wellbeing is examined in four domains: education, health, living conditions and economic situation. Principal component anal...

  20. A Method for Rapid Measurement of Contrast Sensitivity on Mobile Touch-Screens

    Science.gov (United States)

    Mulligan, Jeffrey B.

    2016-01-01

    Touch-screen displays in cell phones and tablet computers are now pervasive, making them an attractive option for vision testing outside of the laboratory or clinic. Here we de- scribe a novel method in which subjects use a finger swipe to indicate the transition from visible to invisible on a grating which is swept in both contrast and frequency. Because a single image can be swiped in about a second, it is practical to use a series of images to zoom in on particular ranges of contrast or frequency, both to increase the accuracy of the measurements and to obtain an estimate of the reliability of the subject. Sensitivities to chromatic and spatio-temporal modulations are easily measured using the same method. A proto- type has been developed for Apple Computer's iPad/iPod/iPhone family of devices, implemented using an open-source scripting environment known as QuIP (QUick Image Processing, http://hsi.arc.nasa.gov/groups/scanpath/research.php). Preliminary data show good agreement with estimates obtained from traditional psychophysical methods as well as newer rapid estimation techniques. Issues relating to device calibration are also discussed.

  1. Subjective Narcosis Assessment Scale: measuring the subjective experience of nitrogen narcosis.

    Science.gov (United States)

    van Wijk, Charles H; Meintjes, W A J

    2014-01-01

    The interaction of subjective experiences and objective measures of neuropsychological performance during hyperbaric exposure has received less attention in the literature, in part due to the shortage of available and appropriately standardized measures. This study aimed to describe the psychometric properties of a modified version of the Subjective High Assessment Scale when used in the hyperbaric context, by exploring internal reliability, factor structure, associations with psychological variables and simple cognitive delayed recall, and the effect of task focus on the recall of subjective experience. Seventy qualified divers completed dry hyperbaric chamber dives to 607.95 kPa, and completed ratings of their subjective experiences. Some also completed a delayed recall task and psychological measures prior to their dives. The scale displayed good internal consistency, with four meaningful factors emerging. It showed some significant but small associations with trait anxiety and transient mood states, and a small to moderate correlation with recall performance. There was no significant effect of task focus on self-report of subjective experiences. The modified scale, renamed the Subjective Narcosis Assessment Scale here, has useful psychometric properties, and promising potential for future use.

  2. Comparing subjective and objective measures of headgear compliance

    NARCIS (Netherlands)

    Bos, A.; Kleverlaan, C.J.; Hoogstraten, J.; Prahl-Andersen, B.; Kuitert, R.

    2007-01-01

    Introduction: Many studies have used subjective measures to examine patient compliance during orthodontic treatment. Objective measurement of compliance has been confined to only a few studies that used electronic timing devices built into removable appliances. Our aim in this study was to compare

  3. Simuluating quantum many-body systems subject to measurements

    DEFF Research Database (Denmark)

    Gammelmark, Søren

    We demonstrate how to simulate both discrete and continuous stochastic evolutions of a quantum many-body system subject to measurements using matrix product states. A particular, but generally applicable, measurement model is analyzed and a simple representation in terms of matrix product operators...

  4. Simulating quantum many-body systems subject to measurements

    DEFF Research Database (Denmark)

    Gammelmark, Søren

    We demonstrate how to simulate both discrete and continuous stochastic evolutions of a quantum many-body system subject to measurements using matrix product states. A particular, but generally applicable, measurement model is analyzed and a simple representation in terms of matrix product operators...

  5. Optimizing measurement of subjective amplitude of accommodation with defocus curves.

    Science.gov (United States)

    Gupta, Navneet; Wolffsohn, James S W; Naroo, Shehzad A

    2008-08-01

    To determine whether letter sequences and/or lens-presentation order should be randomized when measuring defocus curves and to assess the most appropriate criterion for calculating the subjective amplitude of accommodation (AoA) from defocus curves. Eye Clinic, School of Life & Health Sciences, Aston University, Birmingham, United Kingdom. Defocus curves (from +3.00 diopters [D] to -3.00 D in 0.50 D steps) for 6 possible combinations of randomized or nonrandomized letter sequences and/or lens-presentation order were measured in a random order in 20 presbyopic subjects. Subjective AoA was calculated from the defocus curves by curve fitting using various published criteria, and each was correlated to subjective push-up AoA. Objective AoA was measured for comparison of blur tolerance and pupil size. Randomization of lens-presentation order and/or letter sequences, or lack of, did not affect the measured defocus curves (P >.05, analysis of variance). The range of defocus that maintains highest achievable visual acuity (allowing for variability of repeated measurement) was better correlated to (r = 0.84) and agreed best with (+/-0.50 D) subjective push-up AoA than any other relative or absolute acuity criterion used in previous studies. Nonrandomized letters and lens presentation on their own did not affect subjective AoA measured by defocus curves, although their combination should be avoided. Quantification of subjective AoA from defocus curves should be standardized to the range of defocus that maintains the best achievable visual acuity.

  6. Subjective Sleep Measures in Children: Self-Report.

    Science.gov (United States)

    Erwin, Andrea M; Bashore, Lisa

    2017-01-01

    The American Academy of Sleep Medicine (AASM) recently published a consensus statement on the recommended number of hours of sleep in infants and children. The AASM expert panel identified seven health categories in children influenced by sleep duration, a component of sleep quality. For optimal health and general function, children require a certain number of hours of sleep each night. Limited data exist to subjectively assess sleep in this population. Practitioners must evaluate overall sleep quality not simply sleep duration. The purpose of this article is to provide a mini-review of the self-report sleep measures used in children. The authors individually completed a review of the literature for this article via an independent review followed by collaborative discussion. The subjective measures included in this mini-review have been used in children, but not all measures have reported psychometrics. Several tools included in this mini-review measure subjective sleep in children but with limited reliabilities or only preliminary psychometrics. Accurate measurement of self-reported sleep in children is critical to identify sleep problems in this population and further detect associated health problems. Ongoing studies are warranted to establish reliable and valid measures of self-reported sleep in children to accurately detect health problems associated with poor sleep quality. This mini-review of the literature is an important first step to identify the most reliable subjective sleep measures in children.

  7. A measure of subjective happiness: Preliminary reliability and construct validation

    OpenAIRE

    Lyubomirsky, S; Lepper, HS

    1999-01-01

    Using a 'subjectivist' approach to the assessment of happiness, a new 4-item measure of global subjective happiness was developed and validated in 14 studies with a total of 2 732 participants. Data was collected in the United States from students on two college campuses and one high school campus, from community adults in two California cities, and from older adults. Students and community adults in Moscow, Russia also participated in this research. Results indicated that the Subjective Happ...

  8. Dynamic measurements of total hepatic blood flow with Phase Contrast MRI

    Energy Technology Data Exchange (ETDEWEB)

    Yzet, Thierry [Department of Radiology, University Hospital, Place Victor Pauchet, 80054 Amiens cedex 1 (France)], E-mail: Yzet.Thierry@chu-amiens.fr; Bouzerar, Roger [Department of Imaging and Biophysics, University Hospital, Jules Verne University of Picardie, Place Victor Pauchet, 80054 Amiens cedex 1 (France)], E-mail: bouzerar.roger@chu-amiens.fr; Baledent, Olivier [Department of Imaging and Biophysics, University Hospital, Jules Verne University of Picardie, Place Victor Pauchet, 80054 Amiens cedex 1 (France)], E-mail: Olivier.Baledent@chu-amiens.fr; Renard, Cedric [Department of Radiology, University Hospital, Place Victor Pauchet, 80054 Amiens cedex 1 (France)], E-mail: Renard.Cedric@chu-amiens.fr; Lumbala, Didier Mbayo [Department of Radiology, University Hospital, Place Victor Pauchet, 80054 Amiens cedex 1 (France)], E-mail: MbayoLumbala.Didier@chu-amiens.fr; Nguyen-Khac, Eric [Mobile Unit of Alcoology, University Hospital, Place Victor Pauchet, 80054 Amiens cedex 1 (France)], E-mail: Nguyen-Khac.Eric@chu-amiens.fr; Regimbeau, Jean-Marc [Department of Visceral and Digestive General Surgery, University Hospital, Place Victor Pauchet, 80054 Amiens cedex 1 (France)], E-mail: regimbeau.jean-marc@chu-amiens.fr; Deramond, H. [Department of Radiology, University Hospital, Place Victor Pauchet, 80054 Amiens cedex 1 (France)], E-mail: deramond.herve@chu-amiens.fr; Meyer, Marc-Etienne [Department of Imaging and Biophysics, University Hospital, Jules Verne University of Picardie, Place Victor Pauchet, 80054 Amiens cedex 1 (France)], E-mail: Meyer.Marc-Etienne@chu-amiens.fr

    2010-01-15

    Background/Aims: To measure total hepatic blood flow including portal and proper hepatic artery flows as well as the temporal evolution of the vessel's section during a cardiac cycle. Methods: Twenty healthy subjects, with a mean age of 26 years, were explored. Magnetic resonance imaging blood flow measurements were carried out in the portal vein and the proper hepatic artery. MR studies were performed using a 1.5T imager (General Electric Medical Systems). Gradient-echo 2D Fast Cine Phase Contrast sequences were used with both cardiac and respiratory gatings. Data analysis was performed using a semi-automatic software built in our laboratory. Results: The total hepatic flow rate measured was 1.35 {+-} 0.18 L/min or 19.7 {+-} 4.6 mL/(min kg). The proper hepatic artery provided 19.1% of the total hepatic blood flow entering the liver. Those measurements were in agreement with earlier studies using direct measurements. Mean and maximum velocities were also assessed and a discrepancy between our values and the literature's Doppler data was found. Measurements of the portal vein area have shown a mean variation, defined as a 'pulsatility' index of 18% over a cardiac cycle. Conclusions: We report here proper hepatic artery blood flow rate measurements using MRI. Associated with portal flow measurements, we have shown the feasibility of total hepatic flowmetry using a non-invasive and harmless technique.

  9. Contrast mechanisms affecting measurements of photothermal deformations using electronic shearing speckle pattern interferometry

    Science.gov (United States)

    Champion, John Lunsford

    1998-11-01

    The contrast mechanisms affecting measurements of photothermal displacements in plate structures using electronic shearing speckle pattern interferometry are investigated. Full-field measurements of dynamically deforming materials systems obtained with basic and spatial phase stepping shearography techniques are presented. In addition, theoretical models based on linear thermoelasticity are developed for comparison with experiment. These results are obtained through the use of analytical transform techniques. Solutions based on thin plate theory are developed for plate structures that are subjected at the radial edge to simply supported and clamped boundary conditions. In addition, transformed solutions based on three-dimensional thermoelasticity are derived for both the heated and the unheated surfaces of an infinite plate. The important aspects of each theory are identified based on comparisons between experimental results and calculation.

  10. On the relationship between subjective and objective measures of fatigue.

    Science.gov (United States)

    Völker, Ina; Kirchner, Christine; Bock, Otmar Leo

    2016-09-01

    Objective and subjective methods have been used in the past to assess workplace fatigue, but little is known about correlations between them. We examine correlations between subjective and objective measures, including measures collected in a workplace scenario. 15 young and 17 older participants were assessed before and after work with four types of fatigue measure: objective physical (posturography), objective mental (psychomotor vigilance task), subjective physical and mental (self-assessment), objective and subjective realistic (oculomotor behaviour, observer-rated facial expression, typing performance). Pre- and post-test scores were analysed with an ANOVA, significant differences were submitted to a factor analysis. It yielded three factors: one representing posturography, the second self-rated mental and physical fatigue and the third observer-rated facial expression. Results advocate the existence of three independent fatigue components: Objective physical fatigue, introspective and extrospective fatigue. Practitioner Summary: This study analyses correlations between different subjective and objective fatigue markers to better understand the complex nature of workplace fatigue. Measurements were conducted directly at the workplace. Results reveal that fatigue comprises three independent fatigue components: Objective physical fatigue, introspective and extrospective fatigue.

  11. Carboxylated magnetic nanoparticles as MRI contrast agents: Relaxation measurements at different field strengths

    Energy Technology Data Exchange (ETDEWEB)

    Jedlovszky-Hajdu, Angela, E-mail: angela.hajdu@net.sote.hu [Laboratory of Nanochemistry, Department of Biophysics and Radiation Biology, Semmelweis University, Nagyvarad Sq 4, H-1089 Budapest (Hungary); Tombacz, Etelka, E-mail: tombacz@chem.u-szeged.hu [Department of Physical Chemistry and Material Science, University of Szeged, Aradi Vt. Sq 1, Szeged 6720 (Hungary); Banyai, Istvan, E-mail: banyai.istvan@science.unideb.hu [Department of Colloid and Environmental Chemistry, University of Debrecen (Hungary); Babos, Magor, E-mail: babosmagor@yahoo.com [Euromedic Diagnostics Szeged Ltd., Semmelweis St 6, Szeged 6720 (Hungary); Palko, Andras, E-mail: palko@radio.szote.u-szeged.hu [Faculty of Medicine, Department of Radiology, University of Szeged (Hungary)

    2012-09-15

    At the moment the biomedical applications of magnetic fluids are the subject of intensive scientific interest. In the present work, magnetite nanoparticles (MNPs) were synthesized and stabilized in aqueous medium with different carboxylic compounds (citric acid (CA), polyacrylic acid (PAA), and sodium oleate (NaOA)), in order to prepare well stabilized magnetic fluids (MFs). The magnetic nanoparticles can be used in the magnetic resonance imaging (MRI) as contrast agents. Magnetic resonance relaxation measurements of the above MFs were performed at different field strengths (i.e., 0.47, 1.5 and 9.4 T) to reveal the field strength dependence of their magnetic responses, and to compare them with that of ferucarbotran, a well-known superparamagnetic contrast agent. The measurements showed characteristic differences between the tested magnetic fluids stabilized by carboxylic compounds and ferucarbotran. It is worthy of note that our magnetic fluids have the highest r2 relaxivities at the field strength of 1.5 T, where the most of the MRI works in worldwide. - Highlights: Black-Right-Pointing-Pointer Magnetic resonance relaxation measurements were done at different field strengths. Black-Right-Pointing-Pointer Results show characteristic differences between the tested carboxylated MFs. Black-Right-Pointing-Pointer r1 and r2 relaxivities depend on the thickness of the protecting layer. Black-Right-Pointing-Pointer MFs have high r2/r1 ratios at each magnetic field.

  12. Comparing perceptual judgment and subjective measures of spatial awareness.

    Science.gov (United States)

    Bolton, Matthew L; Bass, Ellen J

    2009-07-01

    Spatial awareness is important in domains where safety hinges on human operators keeping track of the relative locations of objects in the environment. While a variety of subjective and judgment-based measures have been used to evaluate spatial awareness, none have probed all three of its levels: (1) identification of environmental objects, (2) their current locations relative to the operator, and (3) their relative positions over time. This work compares new judgment-based measures of spatial awareness that probe all three levels of spatial awareness to conventional subjective measures. In the evaluation of 14 configurations of Synthetic Vision Systems head down displays (seven terrain textures and two Geometric Fields of View (GFOVs)), 18 pilots made four types of judgments (relative angle, distance, height, and abeam time) regarding the location of terrain points displayed in 112 5-s, non-interactive simulations. They also provided subjective demand, awareness, clutter, SA-SWORD, and preferred GFOV measures. Correlation analyses revealed that displays that received higher awareness and SA-SWORD subjective ratings were associated with smaller errors in abeam time judgments and, for SA-SWORD, smaller errors in relative distance judgments. Thus SA-SWORD provides insight into level 2 spatial awareness and both SA-SWORD and awareness provide insight into level 3 spatial awareness. ANOVA and chi(2) analyses revealed comparable results between display configurations that produced the minimum error in judgments and those recommended by the awareness, SA-SWORD, and preferred GFOV measures.

  13. Reproducibility of single-subject functional connectivity measurements.

    Science.gov (United States)

    Anderson, J S; Ferguson, M A; Lopez-Larson, M; Yurgelun-Todd, D

    2011-03-01

    Measurements of resting-state functional connectivity have increasingly been used for characterization of neuropathologic and neurodevelopmental populations. We collected data to characterize how much imaging time is necessary to obtain reproducible quantitative functional connectivity measurements needed for a reliable single-subject diagnostic test. We obtained 100 five-minute BOLD scans on a single subject, divided into 10 sessions of 10 scans each, with the subject at rest or while watching video clips of cartoons. These data were compared with resting-state BOLD scans from 36 healthy control subjects by evaluating the correlation between each pair of 64 small spheric regions of interest obtained from a published functional brain parcellation. Single-subject and group data converged to reliable estimates of individual and population connectivity values proportional to 1 / sqrt(n). Dramatic improvements in reliability were seen by using ≤25 minutes of imaging time, with smaller improvements for additional time. Functional connectivity "fingerprints" for the individual and population began diverging at approximately 15 minutes of imaging time, with increasing reliability even at 4 hours of imaging time. Twenty-five minutes of BOLD imaging time was required before any individual connections could reliably discriminate an individual from a group of healthy control subjects. A classifier discriminating scans during which our subject was resting or watching cartoons was 95% accurate at 10 minutes and 100% accurate at 15 minutes of imaging time. An individual subject and control population converged to reliable different functional connectivity profiles that were task-modulated and could be discriminated with sufficient imaging time.

  14. Designing a new test for contrast sensitivity function measurement with iPad.

    Science.gov (United States)

    Rodríguez-Vallejo, Manuel; Remón, Laura; Monsoriu, Juan A; Furlan, Walter D

    2015-01-01

    To introduce a new application (ClinicCSF) to measure Contrast Sensitivity Function (CSF) with tablet devices, and to compare it against the Functional Acuity Contrast Test (FACT). A total of 42 subjects were arranged in two groups of 21 individuals. Different versions of the ClinicCSF (.v1 and .v2) were used to measure the CSF of each group with the same iPad and the results were compared with those measured with the FACT. The agreements between ClinicCSF and FACT for spatial frequencies of 3, 6, 12 and 18 cycles per degree (cpd) were represented by Bland-Altman plots. Statistically significant differences in CSF of both groups were found due to the change of the ClinicCSF version (p<0.05) while no differences were manifested with the use of the same FACT test. The best agreement with the FACT was found with the ClinicCSF.v2 with no significant differences in all the evaluated spatial frequencies. However, the 95% confidence intervals for mean differences between ClinicCSF and FACT were lower for the version which incorporated a staircase psychophysical method (ClinicCSF.v1), mainly for spatial frequencies of 6, 12 and 18 cpd. The new ClinicCSF application for iPad retina showed no significant differences with FACT test when the same contrast sensitivity steps were used. In addition, it is shown that the accurateness of a vision screening could be improved with the use of an appropriate psychophysical method. Copyright © 2014 Spanish General Council of Optometry. Published by Elsevier Espana. All rights reserved.

  15. Objective and subjective measures of vergence step responses.

    Science.gov (United States)

    Jainta, S; Hoormann, J; Jaschinski, W

    2007-12-01

    Dichoptic nonius lines are used for subjectively (psychophysically) measuring vergence states, but they have been questioned as valid indicators of vergence eye position. In a mirror-stereoscope, we presented convergent and divergent step-stimuli and estimated the vergence response with nonius lines flashed at fixed delays after the disparity step stimulus. For each delay, an adaptive psychophysical procedure was run to determine the physical nonius offset required for subjective alignment; these vergence states were compared with objective eye movement recordings. Between both measures of initial vergence, we calculated the maximal cross-correlation coefficient: the median in our sample was about 0.9 for convergence and divergence, suggesting a good agreement. Relative to the objective measures, the subjective method revealed a smaller vergence velocity and a larger vergence response in the final phase of the response, but both measures were well correlated. The dynamic nonius test is therefore considered to be useful to relatively evaluate a subject's ability in disparity vergence.

  16. Vehicle handling: relationships between subjective and objective measures

    NARCIS (Netherlands)

    Verschuren, R.M.A.F.; Hogema, J.H.

    2003-01-01

    TNO Human Factors and TNO Automotive are investigating relationships between subjective and objective measures in the area of vehicle handling. This paper presents a driving simulator study and a field experiment in which these relationships were investigated. First, in the driving simulator

  17. Comparing objective and subjective error measures for color constancy

    NARCIS (Netherlands)

    Lucassen, M.P.; Gijsenij, A.; Gevers, T.

    2008-01-01

    We compare an objective and a subjective performance measure for color constancy algorithms. Eight hyper-spectral images were rendered under a neutral reference illuminant and four chromatic illuminants (Red, Green, Yellow, Blue). The scenes rendered under the chromatic illuminants were color

  18. Measures of interaction contrast (biological interaction) - ic, ici and icp

    DEFF Research Database (Denmark)

    2015-01-01

    .For the analyzes of binary (or count) data, a fairly well established position holds, that loglinear models estimating measures of relative risk type represent a convenient choice, whereas interactions are often best interpreted if estimated on a linear/additive scale. This code implement the procedure described...... in Hosmer & Lemeshow (1992) and Alfredsson et all (2005) purely in Stata.These two sources however both uses odds ratios as approximations for relational risks. This code on the other hand opens up for using proper estimates of relational risks. To install type "ssc install ic" in the Stata command...

  19. Subjective Quality Measurement of Speech Its Evaluation, Estimation and Applications

    CERN Document Server

    Kondo, Kazuhiro

    2012-01-01

    It is becoming crucial to accurately estimate and monitor speech quality in various ambient environments to guarantee high quality speech communication. This practical hands-on book shows speech intelligibility measurement methods so that the readers can start measuring or estimating speech intelligibility of their own system. The book also introduces subjective and objective speech quality measures, and describes in detail speech intelligibility measurement methods. It introduces a diagnostic rhyme test which uses rhyming word-pairs, and includes: An investigation into the effect of word familiarity on speech intelligibility. Speech intelligibility measurement of localized speech in virtual 3-D acoustic space using the rhyme test. Estimation of speech intelligibility using objective measures, including the ITU standard PESQ measures, and automatic speech recognizers.

  20. How Objective Are Subjective Measures of Organizational Innovativeness, Really?

    Directory of Open Access Journals (Sweden)

    Patrycja Klimas

    2014-06-01

    Full Text Available Purpose: This paper aims to match subjective and objective measures of organizational innovativeness and test correlative relationship between the two. Methodology: The research adopts a quantitative approach, and applies correlation analysis to identify interdependencies. The study has been done in the aviation industry, as organizational innovativeness has so far been described especially in high-tech industries – however it has not been investigated within aviation industry yet. Findings: The results show that the discussions over reliability of research based on subjective measurements techniques are not unfounded. The evidence suggests that subjective measures are not correlated with objective measures, and the outcomes of third-party investigations differ considerably. Therefore decisions about measurements techniques should be deliberate, thought out, theoretically grounded and justifi ed. In general, methodological recommendations provided by this paper could be boiled down to the ascertainment that accurate and reliable assessment of organizational innovativeness should use a set of objective measures addressing all stages of the innovation process. Originality: It should be noted that this study was restricted to only one industry and prone to some common bias. The aviation industry sample was relatively small and purposefully selected, disallowing conclusive statements made outside of this empirical setting. However despite the limitations this paper provides some significant contribution to evaluation and research on innovativeness. It compares two approaches to measurement and empirically proves which approach is more suitable in case of such a highly innovation-intensive sector like aviation. Moreover, it introduces a new in Polish research tool for subjective assessment of organizational innovativeness namely the questionnaire developed by Wang and Ahmed (2004.

  1. Family Medicine in Croatia: Quality Measured by Patients’ Subjective Satisfaction

    OpenAIRE

    Stanić, Arsen; Stevanović, Ranko; Pristaš, Ivan; Tiljak, Hrvoje; Benković, Vanesa; Krčmar, Nevenka; Jovanović, Aleksandar; Jurlina, Nataša; Nott, Teodora

    2007-01-01

    A survey of the subjective assessment of quality in the fi eld of family medicine was conducted on a random sample of 50 family medicine teams distributed proportionally across all Croatian counties, and both rural and urban areas. It measured the satisfaction of insurants/patients, i.e. healthcare service users, on the basis of the completed EUROPEP questionnaire. The survey included 7.271 respondents (the response rate to 15.000 distributed questionnaires was 48.47%). O...

  2. Automatized spleen segmentation in non-contrast-enhanced MR volume data using subject-specific shape priors

    Science.gov (United States)

    Gloger, Oliver; Tönnies, Klaus; Bülow, Robin; Völzke, Henry

    2017-07-01

    To develop the first fully automated 3D spleen segmentation framework derived from T1-weighted magnetic resonance (MR) imaging data and to verify its performance for spleen delineation and volumetry. This approach considers the issue of low contrast between spleen and adjacent tissue in non-contrast-enhanced MR images. Native T1-weighted MR volume data was performed on a 1.5 T MR system in an epidemiological study. We analyzed random subsamples of MR examinations without pathologies to develop and verify the spleen segmentation framework. The framework is modularized to include different kinds of prior knowledge into the segmentation pipeline. Classification by support vector machines differentiates between five different shape types in computed foreground probability maps and recognizes characteristic spleen regions in axial slices of MR volume data. A spleen-shape space generated by training produces subject-specific prior shape knowledge that is then incorporated into a final 3D level set segmentation method. Individually adapted shape-driven forces as well as image-driven forces resulting from refined foreground probability maps steer the level set successfully to the segment the spleen. The framework achieves promising segmentation results with mean Dice coefficients of nearly 0.91 and low volumetric mean errors of 6.3%. The presented spleen segmentation approach can delineate spleen tissue in native MR volume data. Several kinds of prior shape knowledge including subject-specific 3D prior shape knowledge can be used to guide segmentation processes achieving promising results.

  3. Influence of Contrast Media on Bone Mineral Density (BMD) Measurements from Routine Contrast-Enhanced MDCT Datasets using a Phantom-less BMD Measurement Tool.

    Science.gov (United States)

    Toelly, Andrea; Bardach, Constanze; Weber, Michael; Gong, Rui; Lai, Yanbo; Wang, Pei; Guo, Yulin; Kirschke, Jan; Baum, Thomas; Gruber, Michael

    2017-06-01

    Aim  To evaluate the differences in phantom-less bone mineral density (BMD) measurements in contrast-enhanced routine MDCT scans at different contrast phases, and to develop an algorithm for calculating a reliable BMD value. Materials and Methods  112 postmenopausal women from the age of 40 to 77 years (mean age: 57.31 years; SD 9.61) who underwent a clinically indicated MDCT scan, consisting of an unenhanced, an arterial, and a venous phase, were included. A retrospective analysis of the BMD values of the Th12 to L4 vertebrae in each phase was performed using a commercially available phantom-less measurement tool. Results  The mean BMD value in the unenhanced MDCT scans was 79.76 mg/cm³ (SD 31.20), in the arterial phase it was 85.09 mg/cm³ (SD 31.61), and in the venous phase it was 86.18 mg/cm³ (SD 31.30). A significant difference (p contrast-enhanced MDCT scans. There was no significant difference between BMD values in the arterial and venous phases (p = 0.228). The following conversion formulas were calculated using linear regression: unenhanced BMD = -2.287 + 0.964 * [arterial BMD value] and -4.517 + 0.978 * [venous BMD value]. The intrarater agreement of BMD measurements was calculated with an intraclass correlation (ICC) of 0.984 and the interobserver reliability was calculated with an ICC of 0.991. Conclusion  Phantom-less BMD measurements in contrast-enhanced MDCT scans result in increased mean BMD values, but, with the formulas applied in our study, a reliable BMD value can be calculated. However, the mean BMD values did not differ significantly between the arterial and venous phases. Key points   · BMD can be assessed on routine CT scans using a phantom-less tool.. · i. v. contrast agent significantly elevates BMD values measured on routine CT scans.. · BMD values measured in the arterial and venous phase did not differ significantly.. · Conversion formulas were defined for the calculation of a reliable BMD..

  4. Executive function in fibromyalgia: Comparing subjective and objective measures.

    Science.gov (United States)

    Gelonch, Olga; Garolera, Maite; Valls, Joan; Rosselló, Lluís; Pifarré, Josep

    2016-04-01

    There is evidence to suggest the existence of an executive dysfunction in people diagnosed with fibromyalgia, although there are certain inconsistencies between studies. Here, we aim to compare executive performance between patients with fibromyalgia and a control group by using subjective and objective cognitive tests, analyzing the influence of patient mood on the results obtained, and studying associations between the two measures. 82 patients diagnosed with fibromyalgia and 42 healthy controls, matched by age and years of education, were assessed using the Behavioral Rating Inventory of Executive Function - Adult Version (BRIEF-A) as a subjective measure of executive functioning. A selection of objective cognitive tests were also used to measure a series of executive functions and to identify symptoms of depression and anxiety. Patients with fibromyalgia perceived greater difficulties than the control group on all of the BRIEF-A scales. However, after adjustments were made for depression and anxiety the only differences that remained were those associated with the working memory scale and the Metacognition and Global Executive Composite index. In the case of the objective cognitive tests, a significantly worse overall performance was evidenced for the fibromyalgia patients. However, this also disappeared when adjustments were made for depression and anxiety. After this adjustment, fibromyalgia patients only performed significantly worse for the interference effect in the Stroop Test. Although there were no significant associations between most of the objective cognitive tests and the BRIEF-A scales, depression and anxiety exhibited strong associations with almost all of the BRIEF-A scales and with several of the objective cognitive tests. Patients with fibromyalgia showed executive dysfunction in subjective and objective measures, although most of this impairment was associated with mood disturbances. Exceptions to this general rule were observed in the

  5. On the psychophysics of workload - Why bother with subjective measures?

    Science.gov (United States)

    Gopher, D.; Braune, R.

    1984-01-01

    Psychophysical functions describe the relationship between variations in the amplitude of a defined physical quantity and the psychological perception of these changes. Examples are brightness, loudness, and pain. The regularities of these relationships have been formulated into psychophysical laws. The measurement methodology of psychophysical scaling has been refined by the Harvard group led by Stevens (1957 and 1966), who proposed a power function as a general form for such laws. It is argued here that a similar scaling approach can be adapted to the measurement of workload and task demands based upon subjective estimates. The rationale is that these estimates, like other psychophysical judgments, reflect the individual's perception of the amount of processing resources that the subject invests to meet the demand imposed by a task. This approach was successfully applied to the assessment of 21 experimental conditions given to a group of 60 subjects. The paper discusses the main results of this effort and their implications to theory and application in human performance.

  6. SU-F-I-45: An Automated Technique to Measure Image Contrast in Clinical CT Images

    Energy Technology Data Exchange (ETDEWEB)

    Sanders, J; Abadi, E; Meng, B; Samei, E [Duke University, Durham, NC (United States)

    2016-06-15

    Purpose: To develop and validate an automated technique for measuring image contrast in chest computed tomography (CT) exams. Methods: An automated computer algorithm was developed to measure the distribution of Hounsfield units (HUs) inside four major organs: the lungs, liver, aorta, and bones. These organs were first segmented or identified using computer vision and image processing techniques. Regions of interest (ROIs) were automatically placed inside the lungs, liver, and aorta and histograms of the HUs inside the ROIs were constructed. The mean and standard deviation of each histogram were computed for each CT dataset. Comparison of the mean and standard deviation of the HUs in the different organs provides different contrast values. The ROI for the bones is simply the segmentation mask of the bones. Since the histogram for bones does not follow a Gaussian distribution, the 25th and 75th percentile were computed instead of the mean. The sensitivity and accuracy of the algorithm was investigated by comparing the automated measurements with manual measurements. Fifteen contrast enhanced and fifteen non-contrast enhanced chest CT clinical datasets were examined in the validation procedure. Results: The algorithm successfully measured the histograms of the four organs in both contrast and non-contrast enhanced chest CT exams. The automated measurements were in agreement with manual measurements. The algorithm has sufficient sensitivity as indicated by the near unity slope of the automated versus manual measurement plots. Furthermore, the algorithm has sufficient accuracy as indicated by the high coefficient of determination, R2, values ranging from 0.879 to 0.998. Conclusion: Patient-specific image contrast can be measured from clinical datasets. The algorithm can be run on both contrast enhanced and non-enhanced clinical datasets. The method can be applied to automatically assess the contrast characteristics of clinical chest CT images and quantify dependencies

  7. Subjective relevance of objective measures for spatial impression (A)

    DEFF Research Database (Denmark)

    Wang, Lily M.; Gade, Anders Christian

    2000-01-01

    Several objective measures have been proposed to describe the feeling of spatial impression in concert halls, including Lateral Energy Fraction (LF) and Interaural Cross-Correlation Coefficient (IACC). However, previous studies have shown that LF and IACC values did not highly correlate with each...... generated by the room acoustics simulation program ODEON, using four different musical motifs, and were presented to test subjects via headphones. Results from the experiments are presented. [Work supported by ASA Hunt Postdoctoral Research Fellowship.]...... other at individual seat positions in real halls [J. S. Bradley, J. Acoust. Soc. Am. 96, 3525–3535 (1994)]. To investigate the listener envelopment aspect of spatial impression further, subjective paired-comparison tests have been run using signals which have various values for LF, early IACC (from 5...

  8. Reduced visual surround suppression in schizophrenia shown by measuring contrast detection thresholds

    Science.gov (United States)

    Serrano-Pedraza, Ignacio; Romero-Ferreiro, Verónica; Read, Jenny C. A.; Diéguez-Risco, Teresa; Bagney, Alexandra; Caballero-González, Montserrat; Rodríguez-Torresano, Javier; Rodriguez-Jimenez, Roberto

    2014-01-01

    Visual perception in schizophrenia is attracting a broad interest given the deep knowledge that we have about the visual system in healthy populations. One example is the class of effects known collectively as visual surround suppression. For example, the visibility of a grating located in the visual periphery is impaired by the presence of a surrounding grating of the same spatial frequency and orientation. Previous studies have suggested abnormal visual surround suppression in patients with schizophrenia. Given that schizophrenia patients have cortical alterations including hypofunction of NMDA receptors and reduced concentration of GABA neurotransmitter, which affect lateral inhibitory connections, then they should be relatively better than controls at detecting visual stimuli that are usually suppressed. We tested this hypothesis by measuring contrast detection thresholds using a new stimulus configuration. We tested two groups: 21 schizophrenia patients and 24 healthy subjects. Thresholds were obtained using Bayesian staircases in a four-alternative forced-choice detection task where the target was a grating within a 3∘ Butterworth window that appeared in one of four possible positions at 5∘ eccentricity. We compared three conditions, (a) target with no-surround, (b) target embedded within a surrounding grating of 20∘ diameter and 25% contrast with same spatial frequency and orthogonal orientation, and (c) target embedded within a surrounding grating with parallel (same) orientation. Previous results with healthy populations have shown that contrast thresholds are lower for orthogonal and no-surround (NS) conditions than for parallel surround (PS). The log-ratios between parallel and NS thresholds are used as an index quantifying visual surround suppression. Patients performed poorly compared to controls in the NS and orthogonal-surround conditions. However, they performed as well as controls when the surround was parallel, resulting in significantly

  9. Feasibility of Left Ventricular Global Longitudinal Strain Measurements from Contrast-Enhanced Echocardiographic Images.

    Science.gov (United States)

    Medvedofsky, Diego; Lang, Roberto M; Kruse, Eric; Guile, Brittney; Weinert, Lynn; Ciszek, Boguslawa; Jacobson, Zachary; Negron, Jacqueline; Volpato, Valentina; Prado, Aldo; Patel, Amit R; Mor-Avi, Victor

    2017-11-23

    Although left ventricular global longitudinal strain (GLS) is an index of systolic function recommended by the guidelines, poor image quality may hamper strain measurements. While contrast agents are commonly used to improve endocardial visualization, no commercial speckle-tracking software is able to measure strain in contrast-enhanced images. This study aimed to test the accuracy of speckle-tracking software when applied to contrast-enhanced images in patients with suboptimal image quality. We studied patients with a wide range of GLS values who underwent transthoracic echocardiography. Protocol 1 included 44 patients whose images justified use of contrast but still allowed noncontrast speckle-tracking echocardiography (STE), which was judged as accurate and used as a reference. Protocol 2 included 20 patients with poor image quality that precluded noncontrast STE; cardiac magnetic resonance- (CMR-) derived strain was used as the reference instead. Half the manufacturer recommended dose of a commercial contrast agent (Definity/Optison/Lumason) was used to provide partial contrast enhancement. Higher than normal mechanical indices (0.6-0.7) and lowest frequency range for maximal penetration settings were used for imaging. GLS was measured (Epsilon) with and without contrast-enhanced images and by CMR-derived feature tracking (TomTec). Comparisons included linear regression and Bland-Altman analyses. The contrast STE analysis failed in 4/64 patients (6%). Manual corrections were needed to optimize tracking with contrast in all patients. GLS measurements were in good agreement between contrast and noncontrast images (r = 0.85; mean GLS in the contrast images, -12.9% ± 4.7%; bias, 0.34% ± 2.4%). Good agreement was also noted between contrast STE- and CMR-derived strain (r = 0.83; mean, GLS -13.5% ± 4.0%; bias, 0.72% ± 2.5%). We found that GLS measurements from contrast-enhanced images are feasible and accurate in most patients, even in those with poor

  10. Luminance noise as a novel approach for measuring contrast sensitivity within the magnocellular and parvocellular pathways.

    Science.gov (United States)

    Hall, Cierra M; McAnany, J Jason

    2017-07-01

    This study evaluated the extent to which different types of luminance noise can be used to target selectively the inferred magnocellular (MC) and parvocellular (PC) visual pathways. Letter contrast sensitivity (CS) was measured for three visually normal subjects for letters of different size (0.8°-5.3°) under established paradigms intended to target the MC pathway (steady-pedestal paradigm) and PC pathway (pulsed-pedestal paradigm). Results obtained under these paradigms were compared to those obtained in asynchronous static noise (a field of unchanging luminance noise) and asynchronous dynamic noise (a field of randomly changing luminance noise). CS was measured for letters that were high- and low-pass filtered using a range of filter cutoffs to quantify the object frequency information (cycles per letter) mediating letter identification, which was used as an index of the pathway mediating CS. A follow-up experiment was performed to determine the range of letter duration over which MC and PC pathway CS can be targeted. Analysis of variance indicated that the object frequencies measured under the static noise and steady-pedestal paradigms did not differ significantly (p ≥ 0.065), but differed considerably from those measured under the dynamic noise (both p noise, and in dynamic noise. These data suggest that the spatiotemporal characteristics of noise can be manipulated to target the inferred MC (static noise) and PC (dynamic noise) pathways. The results also suggest that CS within these pathways can be measured at long stimulus durations, which has potential importance in the design of future clinical CS tests.

  11. Thickness Measurements from Single X-ray Phase-contrast Speckle Projection

    CERN Document Server

    Xi, Yan; Ma, Jingchen; Zhao, Jun

    2015-01-01

    We propose a one-shot thickness measurement method for sponge-like structures using a propagation-based X-ray phase-contrast imaging (P-PCI) method. In P-PCI, the air-material interface refracts the incident X-ray. Refracted many times along their paths by such a structure, incident X-rays propagate randomly within a small divergent angle range, resulting in a speckle pattern in the captured image. We found structure thickness and contrast of a phase-contrast projection are directly related in images. This relationship can be described by a natural logarithm equation. Thus, from the one phase-contrast view, depth information can be retrieved from its contrast. Our preliminary biological experiments indicate promise in its application to measurements requiring in vivo and ongoing assessment of lung tumor progression.

  12. When evidence of heat-related vulnerability depends on the contrast measure

    Science.gov (United States)

    Benmarhnia, Tarik; Kaufman, Jay S.

    2017-02-01

    Many studies assessing which population subgroups are more vulnerable to heat-related mortality and morbidity have been conducted in recent years. However, given the non-linear (U or J shaped) relationship of temperature with mortality and morbidity, they generally consider only a single contrast measure to report evidence of heat-related vulnerability, despite the possibility that vulnerability depends on the selected contrast measure. In this manuscript, we highlight the importance of considering such issue in further studies by providing evidence for and against heat-related vulnerability using two different temperature contrast measures. We conducted time series analyses to characterize the association between mortality and mean daily temperature in Montreal, Canada (1990-2010). We used age (≥65 vs. 0-64 years) as the effect modifier in stratified analyses. We assessed the presence of effect modification using Cochran Q tests. As contrast measures, we used (1) the percentage change in the outcome above 25 °C, obtained through spline functions showing a linear relationship after this threshold and (2) a comparison of two percentiles (26 vs. 20 °C) of the temperature. We found that evidence of effect modification depended on the contrast measure used. We encourage researchers aiming to identify populations more vulnerable to heat to perform sensitivity analyses using different contrast measures.

  13. Subjectivity

    Directory of Open Access Journals (Sweden)

    Jesús Vega Encabo

    2015-11-01

    Full Text Available In this paper, I claim that subjectivity is a way of being that is constituted through a set of practices in which the self is subject to the dangers of fictionalizing and plotting her life and self-image. I examine some ways of becoming subject through narratives and through theatrical performance before others. Through these practices, a real and active subjectivity is revealed, capable of self-knowledge and self-transformation. 

  14. A Method to Measure and Estimate Normalized Contrast in Infrared Flash Thermography

    Science.gov (United States)

    Koshti, Ajay M.

    2016-01-01

    The paper presents further development in normalized contrast processing used in flash infrared thermography method. Method of computing normalized image or pixel intensity contrast, and normalized temperature contrast are provided. Methods of converting image contrast to temperature contrast and vice versa are provided. Normalized contrast processing in flash thermography is useful in quantitative analysis of flash thermography data including flaw characterization and comparison of experimental results with simulation. Computation of normalized temperature contrast involves use of flash thermography data acquisition set-up with high reflectivity foil and high emissivity tape such that the foil, tape and test object are imaged simultaneously. Methods of assessing other quantitative parameters such as emissivity of object, afterglow heat flux, reflection temperature change and surface temperature during flash thermography are also provided. Temperature imaging and normalized temperature contrast processing provide certain advantages over normalized image contrast processing by reducing effect of reflected energy in images and measurements, therefore providing better quantitative data. Examples of incorporating afterglow heat-flux and reflection temperature evolution in flash thermography simulation are also discussed.

  15. Comparison of the subjective sense of high or low metabolism and objectively measured resting metabolic rate.

    Science.gov (United States)

    Wallhuss, Andreas; Isik, Markus; Nystrom, Fredrik H

    2010-09-01

    To measure caloric intake, physical activity level and resting metabolic rate in participants having the subjective opinion of either having a high or low metabolic rate. Recruitment by local advertising of healthy subjects feeling that they have high or low metabolism, i.e. either a tendency to easily stay lean ('high') or to very easily gain weight ('low') also when taking food intake in comparison with physical activity into account. Walking distance was estimated by pedometry, assessment of caloric intake was determined by food registration. Measurement of resting metabolic rate was performed in the fasting state. We recruited 44 participants with a sense of 'high' metabolism and 12 subjects in the contrasting group. Subjects with 'high' metabolism were leaner ('high': 20.4 +/- 2.1 kg/m(2), 'low': 27.8 +/- 7.5 kg/m(2), p difference in the measured resting metabolic rate between the two groups ('high': 7230 +/- 1233 kJ/24 h, 'low': 7430 +/- 1422 kJ/24 h, p = 0.6), nor was there any difference in physical activity measured by pedometry. Resting metabolic rate was negatively correlated with age and positively correlated with BMI in multivariate analyses of the total cohort. The sense of having a low or high metabolic rate is not related to actual resting metabolic rate.

  16. Quantitative and dynamic measurements of biological fresh samples with X-ray phase contrast tomography

    Energy Technology Data Exchange (ETDEWEB)

    Hoshino, Masato, E-mail: hoshino@spring8.or.jp; Uesugi, Kentaro [Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto, Sayo, Hyogo 679-5198 (Japan); Tsukube, Takuro [Japanese Red Cross Kobe Hospital, 1-3-1 Wakinohamakaigandori, Chuo-ku, Kobe, Hyogo 651-0073 (Japan); Yagi, Naoto [Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto, Sayo, Hyogo 679-5198 (Japan)

    2014-10-08

    Quantitative measurements of biological fresh samples based on three-dimensional densitometry using X-ray phase contrast tomography are presented. X-ray phase contrast tomography using a Talbot grating interferometer was applied to biological fresh samples which were not fixed by any fixatives. To achieve a high-throughput measurement for the fresh samples the X-ray phase contrast tomography measurement procedure was improved. The three-dimensional structure of a fresh mouse fetus was clearly depicted as a mass density map using X-ray phase contrast tomography. The mouse fetus measured in the fresh state was then fixed by formalin and measured in the fixed state. The influence of the formalin fixation on soft tissue was quantitatively evaluated by comparing the fresh and fixed samples. X-ray phase contrast tomography was also applied to the dynamic measurement of a biological fresh sample. Morphological changes of a ring-shaped fresh pig aorta were measured tomographically under different degrees of stretching.

  17. Dynamic measures of regional lung air volume using phase contrast x-ray imaging

    Energy Technology Data Exchange (ETDEWEB)

    Kitchen, M J; Lewis, R A; Morgan, M J; Siu, K K W; Habib, A [School of Physics, Monash University, Melbourne VIC 3800 (Australia); Wallace, M J; Siew, M L; Hooper, S B [Department of Physiology, Monash University, Melbourne VIC 3800 (Australia); Fouras, A [Division of Biological Engineering, Monash University, Melbourne VIC 3800 (Australia); Yagi, N; Uesugi, K [SPring-8/JASRI, Sayo, Hyogo 679-5198 (Japan)], E-mail: Marcus.Kitchen@sci.monash.edu.au

    2008-11-07

    Phase contrast x-ray imaging can provide detailed images of lung morphology with sufficient spatial resolution to observe the terminal airways (alveoli). We demonstrate that quantitative functional and anatomical imaging of lung ventilation can be achieved in vivo using two-dimensional phase contrast x-ray images with high contrast and spatial resolution (<100 {mu}m) in near real time. Changes in lung air volume as small as 25 {mu}L were calculated from the images of term and preterm rabbit pup lungs (n = 28) using a single-image phase retrieval algorithm. Comparisons with plethysmography and computed tomography showed that the technique provided an accurate and robust method of measuring total lung air volumes. Furthermore, regional ventilation was measured by partitioning the phase contrast images, which revealed differences in aeration for different ventilation strategies.

  18. Dynamic measures of regional lung air volume using phase contrast x-ray imaging

    Science.gov (United States)

    Kitchen, M. J.; Lewis, R. A.; Morgan, M. J.; Wallace, M. J.; Siew, M. L.; Siu, K. K. W.; Habib, A.; Fouras, A.; Yagi, N.; Uesugi, K.; Hooper, S. B.

    2008-11-01

    Phase contrast x-ray imaging can provide detailed images of lung morphology with sufficient spatial resolution to observe the terminal airways (alveoli). We demonstrate that quantitative functional and anatomical imaging of lung ventilation can be achieved in vivo using two-dimensional phase contrast x-ray images with high contrast and spatial resolution (lung air volume as small as 25 µL were calculated from the images of term and preterm rabbit pup lungs (n = 28) using a single-image phase retrieval algorithm. Comparisons with plethysmography and computed tomography showed that the technique provided an accurate and robust method of measuring total lung air volumes. Furthermore, regional ventilation was measured by partitioning the phase contrast images, which revealed differences in aeration for different ventilation strategies.

  19. Comparison of Global Cerebral Blood Flow Measured by Phase-Contrast Mapping MRI with O-15-H2O Positron Emission Tomography

    DEFF Research Database (Denmark)

    Vestergaard, Mark Bitsch; Lindberg, Ulrich; Aachmann-Andersen, Niels Jacob

    2017-01-01

    Purpose To compare mean global cerebral blood flow (CBF) measured by phase-contrast mapping magnetic resonance imaging (PCM MRI) and by 15O-H2O positron emission tomography (PET) in healthy subjects. PCM MRI is increasingly being used to measure mean global CBF, but has not been validated in vivo...

  20. Measuring Subjective Happiness by Newly Developed Scale in Tehran, Iran

    Directory of Open Access Journals (Sweden)

    Kambiz Abachizadeh

    2015-10-01

    Full Text Available Background: Happiness as one of the main positive health indicators has drawn more attention in recent years among policy makers and health system managers. There are few studies performed to measure happiness in population-based settings in Iran. In response to this need, our study tends to assess Iranians subjective happiness in Tehran, Capital city of Iran.Materials and Methods: Present study was conducted in Tehran, Capital of Iran, with more than 7 Million populations in January 2013, using a two-step approach. In first step c conceptual framework of Iranians’ happiness was developed. In the second phase of study, a survey recruiting 700 participants was conducted. Stratified cluster sampling method was employed. Participants were recruited from all the 22 municipal divisions of Tehran as strata, proportional to the population size and its gender and age distribution. Happiness was measure by a 40-item questionnaire with scores ranged among 40 to 200.Results: Conceptual framework of Iranians’ happiness based on reviewed documents and consensus building process was the product of first step. At second step, from a pool of 700 persons, 696 (97% agreed to participate and filled out the questionnaire completely.  The mean of happiness score was 143.9 (95% confidence interval, 142.5 to 145.4. The results show that the happiness score of jobless people (135.1, 95%CI: 128.1-142.0 and widowed singles (126.6, 95%CI: 113.0-140.2 were significantly lower than other corresponding groups. There was no significant association between gender, age group, educational level as determinants and happiness.Conclusion: Happiness level of Tehranians is somewhat higher than the moderate level. This finding is consistent with findings of other conducted studies in country. However, it is not consistent with some of international reports of happiness, For instance, Happy Planet Index. Due to inadequate information, it is necessary to conduct more research to

  1. Evaluation of Melbourne Edge Test contrast sensitivity measures in the visually impaired.

    Science.gov (United States)

    Wolffsohn, James S; Eperjesi, Frank; Napper, Genevieve

    2005-07-01

    Contrast sensitivity (CS) provides important information on visual function. This study aimed to assess differences in clinical expediency of the CS increment-matched new back-lit and original paper versions of the Melbourne Edge Test (MET) to determine the CS of the visually impaired. The back-lit and paper MET were administered to 75 visually impaired subjects (28-97 years). Two versions of the back-lit MET acetates were used to match the CS increments with the paper-based MET. Measures of CS were repeated after 30 min and again in the presence of a focal light source directed onto the MET. Visual acuity was measured with a Bailey-Lovie chart and subjects rated how much difficulty they had with face and vehicle recognition. The back-lit MET gave a significantly higher CS than the paper-based version (14.2 +/- 4.1 dB vs 11.3 +/- 4.3 dB, p < 0.001). A significantly higher reading resulted with repetition of the paper-based MET (by 1.0 +/- 1.7 dB, p < 0.001), but this was not evident with the back-lit MET (by 0.1 +/- 1.4 dB, p = 0.53). The MET readings were increased by a focal light source, in both the back-lit (by 0.3 +/- 0.81, p < 0.01) and paper-based (1.2 +/- 1.7, p < 0.001) versions. CS as measured by the back-lit and paper-based versions of the MET was significantly correlated to patients' perceived ability to recognise faces (r = 0.71, r = 0.85 respectively; p < 0.001) and vehicles (r = 0.67, r = 0.82 respectively; p < 0.001), and with distance visual acuity (both r = -0.64; p < 0.001). The CS increment-matched back-lit MET gives higher CS values than the old paper-based test by approximately 3 dB and is more repeatable and less affected by external light sources. Clinically, the MET score provides information on patient difficulties with visual tasks, such as recognising faces.

  2. Examining complexity across domains: relating subjective and objective measures of affective environmental scenes, paintings and music.

    Science.gov (United States)

    Marin, Manuela M; Leder, Helmut

    2013-01-01

    Subjective complexity has been found to be related to hedonic measures of preference, pleasantness and beauty, but there is no consensus about the nature of this relationship in the visual and musical domains. Moreover, the affective content of stimuli has been largely neglected so far in the study of complexity but is crucial in many everyday contexts and in aesthetic experiences. We thus propose a cross-domain approach that acknowledges the multidimensional nature of complexity and that uses a wide range of objective complexity measures combined with subjective ratings. In four experiments, we employed pictures of affective environmental scenes, representational paintings, and Romantic solo and chamber music excerpts. Stimuli were pre-selected to vary in emotional content (pleasantness and arousal) and complexity (low versus high number of elements). For each set of stimuli, in a between-subjects design, ratings of familiarity, complexity, pleasantness and arousal were obtained for a presentation time of 25 s from 152 participants. In line with Berlyne's collative-motivation model, statistical analyses controlling for familiarity revealed a positive relationship between subjective complexity and arousal, and the highest correlations were observed for musical stimuli. Evidence for a mediating role of arousal in the complexity-pleasantness relationship was demonstrated in all experiments, but was only significant for females with regard to music. The direction and strength of the linear relationship between complexity and pleasantness depended on the stimulus type and gender. For environmental scenes, the root mean square contrast measures and measures of compressed file size correlated best with subjective complexity, whereas only edge detection based on phase congruency yielded equivalent results for representational paintings. Measures of compressed file size and event density also showed positive correlations with complexity and arousal in music, which is

  3. Understanding the exposure-time effect on speckle contrast measurements for laser displays

    Science.gov (United States)

    Suzuki, Koji; Kubota, Shigeo

    2017-09-01

    To evaluate the influence of exposure time on speckle noise for laser displays, speckle contrast measurement method was developed observable at a human eye response time using a high-sensitivity camera which has a signal multiplying function. The nonlinearity of camera light sensitivity was calibrated to measure accurate speckle contrasts, and the measuring lower limit noise of speckle contrast was improved by applying spatial-frequency low pass filter to the captured images. Three commercially available laser displays were measured over a wide range of exposure times from tens of milliseconds to several seconds without adjusting the brightness of laser displays. The speckle contrast of raster-scanned mobile projector without any speckle-reduction device was nearly constant over various exposure times. On the contrary to this, in full-frame projection type laser displays equipped with a temporally-averaging speckle-reduction device, some of their speckle contrasts close to the lower limits noise were slightly increased at the shorter exposure time due to the noise. As a result, the exposure-time effect of speckle contrast could not be observed in our measurements, although it is more reasonable to think that the speckle contrasts of laser displays, which are equipped with the temporally-averaging speckle-reduction device, are dependent on the exposure time. This discrepancy may be attributed to the underestimation of temporal averaging factor. We expected that this method is useful for evaluating various laser displays and clarify the relationship between the speckle noise and the exposure time for a further verification of speckle reduction.

  4. The influence of negative mood on heart rate complexity measures and baroreflex sensitivity in healthy subjects.

    Science.gov (United States)

    Köbele, Ralf; Koschke, Mandy; Schulz, Steffen; Wagner, Gerd; Yeragani, Shravya; Ramachandraiah, Chaitra T; Voss, Andreas; Yeragani, Vikram K; Bär, Karl-Jürgen

    2010-01-01

    Decreased cardiac vagal function is linked with increased cardiac mortality and depression is associated with decreased heart rate variability. We have previously shown that the Mood Induction Procedure (MIP) in healthy subjects alters pain perception and thalamic activity during pain perception. To study the effect of negative emotion on heart rate variability and complexity measures as well as on baroreceptor sensitivity, as these parameters reflect cardiac autonomic function. We studied 20 healthy female controls before and after neutral MIP and 20 healthy female subjects before and after negative MIP. We investigated measures of valence of mood, heart rate variability and complexity and the baroreceptor sensitivity index. While there was a significant difference in the valence of mood between the neutral and the negative effect condition, there were no significant differences in any of the heart rate or baroreceptor sensitivity measures between the two groups. Our findings did not show any significant influence of acute negative MIP on heart rate variability and complexity measures and baroreceptor sensitivity, even though depressive disorder and stress are associated with decreased heart rate variability. These findings are discussed in the context of clinical depression and anxiety and the increased risk for cardiac mortality. In contrast to the presented results here, we have previously shown that MIP in healthy subjects alters pain perception and thalamic activity.

  5. Spike-contrast: A novel time scale independent and multivariate measure of spike train synchrony.

    Science.gov (United States)

    Ciba, Manuel; Isomura, Takuya; Jimbo, Yasuhiko; Bahmer, Andreas; Thielemann, Christiane

    2018-01-01

    Synchrony within neuronal networks is thought to be a fundamental feature of neuronal networks. In order to quantify synchrony between spike trains, various synchrony measures were developed. Most of them are time scale dependent and thus require the setting of an appropriate time scale. Recently, alternative methods have been developed, such as the time scale independent SPIKE-distance by Kreuz et al. In this study, a novel time-scale independent spike train synchrony measure called Spike-contrast is proposed. The algorithm is based on the temporal "contrast" (activity vs. non-activity in certain temporal bins) and not only provides a single synchrony value, but also a synchrony curve as a function of the bin size. For most test data sets synchrony values obtained with Spike-contrast are highly correlated with those of the SPIKE-distance (Spearman correlation value of 0.99). Correlation was lower for data containing multiple time scales (Spearman correlation value of 0.89). When analyzing large sets of data, Spike-contrast performed faster. Spike-contrast is compared to the SPIKE-distance algorithm. The test data consisted of artificial spike trains with various levels of synchrony, including Poisson spike trains and bursts, spike trains from simulated neuronal Izhikevich networks, and bursts made of smaller bursts (sub-bursts). The high correlation of Spike-contrast with the established SPIKE-distance for most test data, suggests the suitability of the proposed measure. Both measures are complementary as SPIKE-distance provides a synchrony profile over time, whereas Spike-contrast provides a synchrony curve over bin size. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Biases and power for groups comparison on subjective health measurements.

    Directory of Open Access Journals (Sweden)

    Jean-François Hamel

    Full Text Available Subjective health measurements are increasingly used in clinical research, particularly for patient groups comparisons. Two main types of analytical strategies can be used for such data: so-called classical test theory (CTT, relying on observed scores and models coming from Item Response Theory (IRT relying on a response model relating the items responses to a latent parameter, often called latent trait. Whether IRT or CTT would be the most appropriate method to compare two independent groups of patients on a patient reported outcomes measurement remains unknown and was investigated using simulations. For CTT-based analyses, groups comparison was performed using t-test on the scores. For IRT-based analyses, several methods were compared, according to whether the Rasch model was considered with random effects or with fixed effects, and the group effect was included as a covariate or not. Individual latent traits values were estimated using either a deterministic method or by stochastic approaches. Latent traits were then compared with a t-test. Finally, a two-steps method was performed to compare the latent trait distributions, and a Wald test was performed to test the group effect in the Rasch model including group covariates. The only unbiased IRT-based method was the group covariate Wald's test, performed on the random effects Rasch model. This model displayed the highest observed power, which was similar to the power using the score t-test. These results need to be extended to the case frequently encountered in practice where data are missing and possibly informative.

  7. Measuring Doppler-like power spectra and dermal perfusion using laser speckle contrast with multiple exposures

    Science.gov (United States)

    Thompson, O. B.; Andrews, M. K.

    2010-02-01

    Laser speckle contrast measurements provide effectively instantaneous maps of dermal perfusion, using easily obtainable hardware, but such maps are qualitative. Clinical applications of these techniques require a good theoretical and experimental foundation of understanding before relating them to a physiologically significant, quantitative perfusion value. We have confirmed that multiple-exposure laser speckle methods produce the same spectral information as laser Doppler measurements when applied to targets such as human tissue with embedded moving scatterers. This confirmation is based on both computer simulation of laser speckle data and experimental measurements on Brownian motion and skin perfusion using a laser Doppler system and a multiple-exposure laser speckle system. The Power Spectral Density (PSD) measurements of the light fluctuations derived using both techniques are equivalent. Dermal perfusion images can therefore be measured in exactly equivalent terms by either laser speckle contrast or more laborious scanning laser Doppler methods. Most analyses relating laser speckle contrast to perfusion depend on assuming a particular temporal autocorrelation function for the light intensity fluctuations in biospeckle. Using multiple-exposure laser speckle allows the autocorrelation function to be measured rather than assumed. Measured autocorrelation functions and their related power spectra for dermal perfusion are presented, including measurements under arterial occlusion to investigate a 'biological zero': the speckle blur relating to the remaining movement of tissue constituents when there is no net blood flow.

  8. Diagnosis of Spinal Lesions Using Heuristic and Pharmacokinetic Parameters Measured by Dynamic Contrast-Enhanced MRI.

    Science.gov (United States)

    Lang, Ning; Yuan, Huishu; Yu, Hon J; Su, Min-Ying

    2017-07-01

    This study aimed to evaluate the diagnostic performance of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) in differentiation of four spinal lesions by using heuristic and pharmacokinetic parameters analyzed from DCE signal intensity time course. DCE-MRI of 62 subjects with confirmed myeloma (n = 9), metastatic cancer (n = 22), lymphoma (n = 7), and inflammatory tuberculosis (TB) (n = 24) in the spine were analyzed retrospectively. The region of interest was placed on strongly enhanced tissues. The DCE time course was categorized as the "wash-out," "plateau," or "persistent enhancement" pattern. The maximum enhancement, steepest wash-in enhancement, and wash-out slope using the signal intensity at 67 seconds after contrast injection as reference were measured. The Tofts 2-compartmental pharmacokinetic model was applied to obtain K trans and k ep . Pearson correlation between heuristic and pharmacokinetic parameters was evaluated, and receiver operating characteristic curve analysis was performed for pairwise group differentiation. The mean wash-out slope was -22% ± 10% for myeloma, 1% ± 0.4% for metastatic cancer, 3% ± 3% for lymphoma, and 7% ± 10% for TB, and it could significantly distinguish myeloma from metastasis (area under the curve [AUC] = 0.884), lymphoma (AUC = 1.0), and TB (AUC = 1.0) with P = .001, and distinguish metastasis from TB (AUC = 0.741) with P = .005. The k ep and wash-out slope were highly correlated (r = 0.92), and they showed a similar diagnostic performance. The K trans was significantly correlated with the maximum enhancement (r = 0.71) and the steepest wash-in enhancement (r = 0.85), but they had inferior diagnostic performance compared to the wash-out slope. DCE-MRI may provide additional diagnostic information, and a simple wash-out slope had the best diagnostic performance. The heuristic and pharmacokinetic parameters were highly correlated

  9. Electrophysiological measures of temporal resolution, contrast sensitivity and spatial resolving power in sharks.

    Science.gov (United States)

    Ryan, Laura A; Hemmi, Jan M; Collin, Shaun P; Hart, Nathan S

    2017-03-01

    In most animals, vision plays an important role in detecting prey, predators and conspecifics. The effectiveness of vision in assessing cues such as motion and shape is influenced by the ability of the visual system to detect changes in contrast in both space and time. Understanding the role vision plays in shark behaviour has been limited by a lack of knowledge about their temporal resolution, contrast sensitivity and spatial resolution. In this study, an electrophysiological approach was used to compare these measures across five species of sharks: Chiloscyllium punctatum, Heterodontus portusjacksoni, Hemiscyllium ocellatum, Mustelus mustelus and Haploblepharus edwardsii. All shark species were highly sensitive to brightness contrast and were able to detect contrast differences as low as 1.6%. Temporal resolution of flickering stimuli ranged from 28 to 44 Hz. Species that inhabit brighter environments were found to have higher temporal resolution. Spatial resolving power was estimated in C. punctatum, H. portusjacksoni and H. ocellatum and ranged from 0.10 to 0.35 cycles per degree, which is relatively low compared to other vertebrates. These results suggest that sharks have retinal adaptations that enhance contrast sensitivity at the expense of temporal and spatial resolution, which is beneficial for vision in dimly lit and/or low contrast aquatic environments.

  10. Inter-Display Reproducibility of Contrast Sensitivity Measurement with iPad.

    Science.gov (United States)

    Rodríguez-Vallejo, Manuel; Monsoriu, Juan A; Furlan, Walter D

    2016-12-01

    To evaluate the reliability of measuring CS with uncalibrated iPads. Six random iPads with retina display were calibrated with a colorimeter and the correlation between Luminance (L) and pixel level (y) was computed according to an exponential function. The mean and confidence interval (±2SD) obtained from the six iPads were calculated and the bit-stealing technique was applied for expanding y from 256 to 2540 possible values. The L of the optotype was computed for the selected contrast values (logC) represented in log units, using 0.1 log and 0.05 log steps. At each particular y, the contrast was considered reliable when the mean L plus 2SD was less than half the difference of luminance between two consecutive levels of contrast. Differences between the iPads for the Experimental logC were evaluated with the Friedman test. Luminance properties vary between devices, which were reflected in the computed Experimental logC (p iPads with the same retina display, making it necessary to calibrate each display to achieve accurate luminance and contrast steps of 0.05 log units or less. However, for screening purposes utilizing contrast steps of 0.1 log unit or greater for a validated psychophysical test, calibration is not required to achieve accurate results across the displays described herein.

  11. Maintenance Models for Systems subject to Measurable Deterioration

    NARCIS (Netherlands)

    R.P. Nicolai (Robin)

    2008-01-01

    textabstractComplex engineering systems such as bridges, roads, flood defence structures, and power pylons play an important role in our society. Unfortunately such systems are subject to deterioration, meaning that in course of time their condition falls from higher to lower, and possibly even to

  12. In which patients should serum creatinine be measured before iodinated contrast medium administration?

    Energy Technology Data Exchange (ETDEWEB)

    Thomsen, Henrik S. [Copenhagen University Hospital, Herlev (Denmark). Department of Diagnostic Radiology; Morcos, Sameh K. [Northern General Hospital, Department of Diagnostic Imaging, Sheffield Teaching Hospitals NHS Trust, Sheffield (United Kingdom)

    2005-04-01

    Routine measurement of serum creatinine before injection of intravascular iodinated contrast material in all patients would be cumbersome and have an associated cost. There is doubt about whether serum creatinine should be measured routinely in all patients or selectively. The Contrast Media Safety Committee of the European Society of Urogenital Radiology decided to review the literature and draw up guidelines on this important practical issue. A literature search was carried out and summarized in a report. Based on the available information and discussions amongst the members of the Committee, guidelines were produced. The report and guidelines were discussed at the 11th European Symposium on Urogenital Radiology in Santiago de Compostela, Spain. The practice for identifying patients at risk of contrast medium induced nephropathy varies considerably from one institution to another. Patients at risk constitute only a small percentage of all cases referred for contrast enhanced imaging examination. However, it is important to identify them and take the necessary precautions. Recent serum creatinine level should be available in patients with an increased probability of a raised serum creatinine level (renal disease, renal surgery, proteinuria, diabetes mellitus, hypertension, gout, current intake of nephrotoxic drugs). A simple guideline has been produced. (orig.)

  13. Simultaneous blood flow and blood oxygenation measurements using a combination of diffuse speckle contrast analysis and near-infrared spectroscopy.

    Science.gov (United States)

    Seong, Myeongsu; Phillips, Zephaniah; Mai, Phuong Minh; Yeo, Chaebeom; Song, Cheol; Lee, Kijoon; Kim, Jae Gwan

    2016-02-01

    A combined diffuse speckle contrast analysis (DSCA)-near-infrared spectroscopy (NIRS) system is proposed to simultaneously measure qualitative blood flow and blood oxygenation changes in human tissue. The system employs an optical switch to alternate two laser sources at two different wavelengths and a CCD camera to capture the speckle image. Therefore, an optical density can be measured from two wavelengths for NIRS measurements and a speckle contrast can be calculated for DSCA measurements. In order to validate the system, a flow phantom test and an arm occlusion protocol for arterial and venous occlusion were performed. Shorter exposure times (<1 ms ) show a higher drop (between 50% and 66%) and recovery of 1/K²S values after occlusion (approximately 150%), but longer exposure time (3 ms) shows more consistent hemodynamic changes. For four subjects, the 1/K²S values dropped to an average of 82.1±4.0% during the occlusion period and the average recovery of 1/K²S values after occlusion was 109.1±0.8% . There was also an approximately equivalent amplitude change in oxyhemoglobin (OHb) and deoxyhemoglobin (RHb) during arterial occlusion (max RHb=0.0085±0.0024 mM/DPF, min OHb=-0.0057±0.0044 mM/DPF). The sensitivity of the system makes it a suitable modality to observe qualitative hemodynamic trends during induced physiological changes.

  14. Subjective sleepiness and sleep quality in adolescents are related to objective and subjective measures of school performance

    NARCIS (Netherlands)

    Boschloo, Annemarie; Krabbendam, Lydia; Dekker, Sanne; Lee, Nikki; De Groot, Renate; Jolles, Jelle

    2016-01-01

    This study investigated the relation between sleep and school performance in a large sample of 561 adolescents aged 11–18 years. Three subjective measures of sleep were used: sleepiness, sleep quality, and sleep duration. They were compared to three measures of school performance: objective school

  15. Subjective sleepiness and sleep quality in adolescents are related to objective and subjective measures of school performance

    NARCIS (Netherlands)

    Boschloo, Annemarie; Krabbendam, Lydia; Dekker, Sanne; Lee, Nikki; De Groot, Renate; Jolles, Jelle

    2018-01-01

    This study investigated the relation between sleep and school performance in a large sam- ple of 561 adolescents aged 11–18 years. Three subjective measures of sleep were used: sleepiness, sleep quality, and sleep duration. They were compared to three measures of school performance: objective school

  16. Subjective sleepiness and sleep quality in adolescents are related to objective and subjective measures of school performance

    NARCIS (Netherlands)

    Boschloo, A.; Krabbendam, L.; Dekker, S.; Lee, N.; Groot, R. de; Jolles, J.

    2013-01-01

    This study investigated the relation between sleep and school performance in a large sample of 561 adolescents aged 11-18 years. Three subjective measures of sleep were used: sleepiness, sleep quality, and sleep duration. They were compared to three measures of school performance: objective school

  17. Subjectively and objectively measured sleep with and without posttraumatic stress disorder and trauma exposure.

    Science.gov (United States)

    Kobayashi, Ihori; Huntley, Edward; Lavela, Joseph; Mellman, Thomas A

    2012-07-01

    Although reports of sleep disturbances are common among individuals with posttraumatic stress disorder (PTSD), results of polysomnographic (PSG) studies have inconsistently documented abnormalities and have therefore suggested "sleep state misperception." The authors' study objectives were to compare sleep parameters measured objectively and subjectively in the laboratory and at home in civilians with and without trauma exposure and PTSD. Cross-sectional study. PSG recordings in a sleep laboratory and actigraphic recordings in participants' homes. One hundred three urban-residing African Americans with and without trauma exposure and PTSD who participated in a larger study. N/A. Sleep parameters (total sleep time [TST], sleep onset latency [SOL], and wake after sleep onset [WASO]) were assessed using laboratory PSG and home actigraphy. A sleep diary was completed in the morning after PSG and actigraphy recordings. Habitual TST, SOL, and WASO were assessed using a sleep questionnaire. The Clinician Administered PTSD Scale was administered to assess participants' trauma exposure and PTSD diagnostic status. Participants, regardless of their trauma exposure/PTSD status, underestimated WASO in the diary and questionnaire relative to actigraphy and overestimated SOL in the diary relative to PSG. Among participants with current PTSD, TST diary estimates did not differ from the actigraphy measure in contrast with those without current PTSD who overestimated TST. No other significant group differences in discrepancies between subjective and objective sleep measures were found. Discrepancies between subjectively and objectively measured sleep parameters were not associated with trauma exposure or PTSD. This challenges prior assertions that individuals with PTSD overreport their sleep disturbances.

  18. Subjective Sleep Measures in Children: Self-Report

    OpenAIRE

    Erwin, Andrea M.; Bashore, Lisa

    2017-01-01

    The American Academy of Sleep Medicine (AASM) recently published a consensus statement on the recommended number of hours of sleep in infants and children. The AASM expert panel identified seven health categories in children influenced by sleep duration, a component of sleep quality. For optimal health and general function, children require a certain number of hours of sleep each night. Limited data exist to subjectively assess sleep in this population. Practitioners must evaluate overall sle...

  19. Measurement of tendon reflexes by surface electromyography in normal subjects

    NARCIS (Netherlands)

    Stam, J.; van Crevel, H.

    1989-01-01

    A simple method for measuring the tendon reflexes was developed. A manually operated, electronic reflex hammer was applied that enabled measurement of the strength of tendon taps. Reflex responses were recorded by surface electromyography. Stimulus-response relations and latencies of tendon reflexes

  20. Influence of IV Contrast Administration on CT Measures of Muscle and Bone Attenuation: Implications for Sarcopenia and Osteoporosis Evaluation.

    Science.gov (United States)

    Boutin, Robert D; Kaptuch, Justin M; Bateni, Cyrus P; Chalfant, James S; Yao, Lawrence

    2016-11-01

    The objective of our study was to characterize enhancement of muscle and bone that occurs on standardized four-phase contrast-enhanced CT. Two musculoskeletal radiologists reviewed standardized four-phase abdominal CT scans obtained with IV contrast material. The psoas area was measured, and the mean attenuation (in Hounsfield units) was recorded for the aorta, psoas muscles, posterior paraspinal muscles, and L4 vertebral body. CT attenuation measures were compared between anatomic regions and imaging phases with the paired t test; associations between measures were examined with the Pearson correlation coefficient (R). The study included 201 patients (97 men, 104 women; mean age, 57.7 ± 12.5 [SD] years). Subject age was inversely correlated with unenhanced attenuation in the psoas muscles, posterior paraspinal muscles, and L4 (p muscles, posterior paraspinal muscles, and L4 enhanced significantly (p muscle enhancement was observed on delayed phase scans, whereas the greatest enhancement in L4 was seen on portal phase imaging. The unenhanced attenuation of the psoas muscles was significantly and negatively correlated with enhancement of the psoas muscles at the portal and delayed phases (p muscles. Age was positively correlated with posterior paraspinal muscle enhancement at the portal and delayed phases in men (p muscle and bone regions is routinely observed and should be considered when using CT attenuation values as biomarkers of sarcopenia and osteoporosis. Furthermore, CT enhancement may be significantly influenced by age, sex, and unenhanced tissue attenuation.

  1. Comparison of arterial input functions measured from ultra-fast dynamic contrast enhanced MRI and dynamic contrast enhanced computed tomography in prostate cancer patients

    Science.gov (United States)

    Wang, Shiyang; Lu, Zhengfeng; Fan, Xiaobing; Medved, Milica; Jiang, Xia; Sammet, Steffen; Yousuf, Ambereen; Pineda, Federico; Oto, Aytekin; Karczmar, Gregory S.

    2018-02-01

    The purpose of this study was to evaluate the accuracy of arterial input functions (AIFs) measured from dynamic contrast enhanced (DCE) MRI following a low dose of contrast media injection. The AIFs measured from DCE computed tomography (CT) were used as ‘gold standard’. A total of twenty patients received CT and MRI scans on the same day. Patients received 120 ml Iohexol in DCE-CT and a low dose of (0.015 mM kg‑1) of gadobenate dimeglumine in DCE-MRI. The AIFs were measured in the iliac artery and normalized to the CT and MRI contrast agent doses. To correct for different temporal resolution and sampling periods of CT and MRI, an empirical mathematical model (EMM) was used to fit the AIFs first. Then numerical AIFs (AIFCT and AIFMRI) were calculated based on fitting parameters. The AIFMRI was convolved with a ‘contrast agent injection’ function (AIFMRICON ) to correct for the difference between MRI and CT contrast agent injection times (~1.5 s versus 30 s). The results show that the EMMs accurately fitted AIFs measured from CT and MRI. There was no significant difference (p  >  0.05) between the maximum peak amplitude of AIFs from CT (22.1  ±  4.1 mM/dose) and MRI after convolution (22.3  ±  5.2 mM/dose). The shapes of the AIFCT and AIFMRICON were very similar. Our results demonstrated that AIFs can be accurately measured by MRI following low dose contrast agent injection.

  2. Intravenous contrast injection significantly affects bone mineral density measured on CT

    Energy Technology Data Exchange (ETDEWEB)

    Pompe, Esther; Willemink, Martin J.; Dijkhuis, Gawein R.; Verhaar, Harald J.J.; Hoesein, Firdaus A.A.M.; Jong, Pim A. de [University Medical Center Utrecht, Department of Radiology and Internal Medicine-Geriatrics, Postbus 85500, Postbox: E.03.511, GA, Utrecht (Netherlands)

    2014-09-05

    The objective is to evaluate the effect of intravenous contrast media on bone mineral density (BMD) assessment by comparing unenhanced and contrast-enhanced computed tomography (CT) examinations performed for other indications. One hundred and fifty-two patients (99 without and 53 with malignant neoplasm) who underwent both unenhanced and two contrast-enhanced (arterial and portal venous phase) abdominal CT examinations in a single session between June 2011 and July 2013 were included. BMD was evaluated on the three examinations as CT-attenuation values in Hounsfield Units (HU) in the first lumbar vertebra (L1). CT-attenuation values were significantly higher in both contrast-enhanced phases, compared to the unenhanced phase (p < 0.01). In patients without malignancies, mean ± standard deviation (SD) HU-values increased from 128.8 ± 48.6 HU for the unenhanced phase to 142.3 ± 47.2 HU for the arterial phase and 147.0 ± 47.4 HU for the portal phase (p < 0.01). In patients with malignancies, HU-values increased from 112.1 ± 38.1 HU to 126.2 ± 38.4 HU and 130.1 ± 37.3 HU (p < 0.02), respectively. With different thresholds to define osteoporosis, measurements in the arterial and portal phase resulted in 7-25 % false negatives. Our study showed that intravenous contrast injection substantially affects BMD-assessment on CT and taking this into account may improve routine assessment of low BMD in nonquantitative CT. (orig.)

  3. Turbulent stress measurements with phase-contrast magnetic resonance through tilted slices

    Energy Technology Data Exchange (ETDEWEB)

    MacKenzie, Jordan; Soederberg, Daniel; Lundell, Fredrik [Linne FLOW Centre, KTH Mechanics, Stockholm (Sweden); Swerin, Agne [SP Technical Research Institute of Sweden-Chemistry, Materials and Surfaces, Stockholm (Sweden); KTH Royal Institute of Technology, Surface and Corrosion Science, Stockholm (Sweden)

    2017-05-15

    Aiming at turbulent measurements in opaque suspensions, a simplistic methodology for measuring the turbulent stresses with phase-contrast magnetic resonance velocimetry is described. The method relies on flow-compensated and flow-encoding protocols with the flow encoding gradient normal to the slice. The experimental data is compared with direct numerical simulations (DNS), both directly but also, more importantly, after spatial averaging of the DNS data that resembles the measurement and data treatment of the experimental data. The results show that the most important MRI data (streamwise velocity, streamwise variance and Reynolds shear stress) is reliable up to at least anti r = 0.75 without any correction, paving the way for dearly needed turbulence and stress measurements in opaque suspensions. (orig.)

  4. Influence of photo-detector's dead-time on the speckle contrast for blood flow measurement

    Directory of Open Access Journals (Sweden)

    N. Cruz-Ojeda

    2015-12-01

    Full Text Available The statistics of temporal integration of dynamically scattered light is commonly employed to calculate the correlation time of the light and related physical properties of the object that produce it, i.e. scatterer's speed. Recently, studying the statistics of time-averaged fluorescence intensity, it was reported that a small dead-time (1% of the exposure time of the photo-detector increases the correlation time by one order of magnitude compared with an ideal photo-detector. Applying the same theory to the speckle contrast calculation for blood flow measurement, we found that the effect of dead-time is negligible compared to an ideal photo-detector for contrast calculation.

  5. Subject bias in three self-report measures of change.

    NARCIS (Netherlands)

    Sprangers, M.; Hoogstraten, J.

    1991-01-01

    Examined whether 3 measures of self-reported change (post minus pre difference scores, post minus then difference scores, and direct improvement scores) are susceptible to training related S bias. 19 university students were assigned to a study planning (experimental) group, 19 to a text studying

  6. Pilot workload evaluated with subjective and physiological measures

    NARCIS (Netherlands)

    Veltman, J.A.; Gaillard, A.W.K.

    1993-01-01

    The aim of the present study is to validate different measures for mental workload. Ten aspirant fighter jet pilots flew several scenarios in a flight simulator. The scenarios were divided into segments with different levels of task load. During the flight, heart rate, respiration and blood pressure

  7. Feasibility of measuring renal blood flow by phase-contrast magnetic resonance imaging in patients with autosomal dominant polycystic kidney disease

    Energy Technology Data Exchange (ETDEWEB)

    Spithoven, E.M.; Meijer, E.; Boertien, W.E.; Gaillard, C.A.J.M.; Jong, P.E. de; Gansevoort, R.T. [University of Groningen, Department of Nephrology, Community and Occupational Medicine, University Medical Center Groningen, PO Box 30.001, RB Groningen (Netherlands); Borns, C.; Kappert, P.; Greuter, M.J.W.; Jagt, E. van der [University of Groningen, Department of Radiology, Community and Occupational Medicine, University Medical Center Groningen, Groningen (Netherlands); Vart, P. [University of Groningen, Department of Health Sciences, Community and Occupational Medicine, University Medical Center Groningen, Groningen (Netherlands)

    2016-03-15

    Renal blood flow (RBF) has been shown to predict disease progression in autosomal dominant polycystic kidney disease (ADPKD). We investigated the feasibility and accuracy of phase-contrast RBF by MRI (RBF{sub MRI}) in ADPKD patients with a wide range of estimated glomerular filtration rate (eGFR) values. First, we validated RBF{sub MRI} measurement using phantoms simulating renal artery hemodynamics. Thereafter, we investigated in a test-set of 21 patients intra- and inter-observer coefficient of variation of RBF{sub MRI}. After validation, we measured RBF{sub MRI} in a cohort of 91 patients and compared the variability explained by characteristics indicative for disease severity for RBF{sub MRI} and RBF measured by continuous hippuran infusion. The correlation in flow measurement using phantoms by phase-contrast MRI was high and fluid collection was high (CCC=0.969). Technical problems that precluded RBF{sub MRI} measurement occurred predominantly in patients with a lower eGFR (34% vs. 16%). In subjects with higher eGFRs, variability in RBF explained by disease characteristics was similar for RBF{sub MRI} compared to RBF{sub Hip,} whereas in subjects with lower eGFRs, this was significantly less for RBF{sub MRI}. Our study shows that RBF can be measured accurately in ADPKD patients by phase-contrast, but this technique may be less feasible in subjects with a lower eGFR. (orig.)

  8. Subjective sleepiness and sleep quality in adolescents are related to objective and subjective measures of school performance

    OpenAIRE

    Annemarie eBoschloo; Lydia eKrabbendam; Sanne eDekker; Lee, Nikki C.; Renate ede Groot; Jelle eJolles

    2013-01-01

    This study investigated the relation between sleep and school performance in a large sample of 561 adolescents aged 11-18 years. Three subjective measures of sleep were used: sleepiness, sleep quality and sleep duration. They were compared to three measures of school performance: objective school grades, self-reported school performance, and parent-reported school performance. Sleepiness – ‘I feel sleepy during the first hours at school’ – appeared to predict both school grades and self-repor...

  9. Measuring Graph Literacy without a Test: A Brief Subjective Assessment.

    Science.gov (United States)

    Garcia-Retamero, Rocio; Cokely, Edward T; Ghazal, Saima; Joeris, Alexander

    2016-10-01

    Visual aids tend to help diverse and vulnerable individuals understand risk communications, as long as these individuals have a basic understanding of graphs (i.e., graph literacy). Tests of objective graph literacy (OGL) can effectively identify individuals with limited skills, highlighting vulnerabilities and facilitating custom-tailored risk communication. However, the administration of these tests can be time-consuming and may evoke negative emotional reactions (e.g., anxiety). To evaluate a brief and easy-to-use assessment of subjective graph literacy (SGL) (i.e., self-reported ability to process and use graphically presented information) and to estimate the robustness and validity of the SGL scale and compare it with the leading OGL scale in diverse samples from different cultures. Demographically diverse residents (n = 470) of the United States, young adults (n = 172) and patients (n = 175) from Spain, and surgeons (n = 175) from 48 countries. A focus group and 4 studies for instrument development and initial validation (study 1), reliability and convergent and discriminant validity evaluation (study 2), and predictive validity estimation (studies 3 and 4). Psychometric properties of the scale. In about 1 minute, the SGL scale provides a reliable, robust, and valid assessment of skills and risk communication preferences and evokes fewer negative emotional reactions than the OGL scale. The SGL scale can be suitable for use in clinical research and may be useful as a communication aid in clinical practice. Theoretical mechanisms involved in SGL, emerging applications, limitations, and open questions are discussed. © The Author(s) 2016.

  10. Time-efficient myocardial contrast partition coefficient measurement from early enhancement with magnetic resonance imaging.

    Directory of Open Access Journals (Sweden)

    Shi-Jun Zhang

    Full Text Available OBJECTIVE: Our purpose was to validate an early enhancement time point for accurately measuring the myocardial contrast partition coefficient (lambda using dynamic-equilibrium magnetic resonance imaging. MATERIALS AND METHODS: The pre- and post-contrast longitudinal relaxation rates (reciprocal of T1 of the interventricular septum (R1(m and blood pool (R1(b were obtained from fifteen healthy volunteers and three diabetic patients with hypertension using two optimized T1 mapping sequences (modified Look-Locker inversion recovery on a 3-Tesla magnetic resonance scanner. Reference lambda values were calculated as the slope of the regression line of R1(m versus R1(b at dynamic equilibrium (multi-point regression method. The simplified pre-/post-enhancement two-acquisition method (two-point method was used to calculate lambda by relating the change in R1(m and R1(b using different protocols according to the acquisition stage of the post-enhancement data point. The agreement with the referential method was tested by calculating Pearson's correlation coefficient and the intra-class correlation coefficient. RESULTS: The lambda values measured by the two-point method increased (from 0.479 ± 0.041 to 0.534 ± 0.043 over time from 6 to 45 minutes after contrast and exhibited good correlation with the reference at each time point (r ≥ 0.875, p<0.05. The intra-class correlation coefficient on absolute agreement with the reference lambda was 0.946, 0.929 and 0.922 at the 6th, 7th and 8th minutes and dropped from 0.878 to 0.403 from the 9th minute on. CONCLUSIONS: The time-efficient two-point method at 6-8 minutes after the Gd-DTPA bolus injection exhibited good agreement with the multi-point regression method and can be applied for accurate lambda measurement in normal myocardium.

  11. Measuring sparse temporal-variation for accurate registration of dynamic contrast-enhanced breast MR images.

    Science.gov (United States)

    Zheng, Yuanjie; Wei, Benzheng; Liu, Hui; Xiao, Rui; Gee, James C

    2015-12-01

    Accurate registration of dynamic contrast-enhanced (DCE) MR breast images is challenging due to the temporal variations of image intensity and the non-rigidity of breast motion. The former can cause the well-known tumor shrinking/expanding problem in registration process while the latter complicates the task by requiring an estimation of non-rigid deformation. In this paper, we treat the intensity's temporal variations as "corruptions" which spatially distribute in a sparse pattern and model them with a L1 norm and a Lorentzian norm. We show that these new image similarity measurements can characterize the non-Gaussian property of the difference between the pre-contrast and post-contrast images and help to resolve the shrinking/expanding problem by forgiving significant image variations. Furthermore, we propose an iteratively re-weighted least squares based method and a linear programming based technique for optimizing the objective functions obtained using these two novel norms. We show that these optimization techniques outperform the traditional gradient-descent approach. Experimental results with sequential DCE-MR images from 28 patients show the superior performances of our algorithms. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. Measurement of dynamic scattering beneath stationary layers using multiple-exposure laser speckle contrast analysis

    Science.gov (United States)

    Hirst, Evan; Thompson, Oliver; Andrews, Mike

    2013-02-01

    The retina/choroid structure is an example of a complex biological target featuring highly perfused tissues and vessel flows both near the surface and at some depth. Laser speckle imaging can be used to image blood flows but static scattering paths present a problem for extracting quantifiable data. The speckle contrast is artificially increased by any residual specular reflection and light paths where no moving scatterers are encountered. Here we present results from phantom experiments demonstrating that the static and dynamic contributions to laser speckle contrast can be separated when camera exposures of varying duration are used. The stationary contrast parameter follows the thickness and strength of the overlying scatterer while the dynamic proportion of the scatter resulting from vessel flows and Brownian motion is unchanged. The importance of separating the two scatter components is illustrated by in vivo measurements from a scarred human retina, where the effect of the un-perfused scar tissue can be decoupled from the dynamic speckle from the intact tissue beneath it.

  13. Are the visual transients from microsaccades helpful? Measuring the influences of small saccades on contrast sensitivity.

    Science.gov (United States)

    Mostofi, Naghmeh; Boi, Marco; Rucci, Michele

    2016-01-01

    Like all saccades, microsaccades cause both spatial and temporal changes in the input to the retina. In space, recent studies have shown that these small shifts precisely relocate a narrow (smaller than the foveola) high-acuity retinal locus on the stimulus. However, it has long been questioned whether the temporal modulations resulting from microsaccades are also beneficial for vision. To address this question, we combined spectral analysis of the visual input to the retina with measurements of contrast sensitivity in humans. Estimation of how different types of eye movements redistribute the power of an otherwise stationary stimulus shows that small saccades contribute more temporal power than ocular drift in the low-frequency range, suggesting a specific role for these movements in the encoding of low spatial frequencies. However, an influence on contrast sensitivity was only found for saccades with amplitudes larger than 30'. Contrast thresholds remained highly similar in the presence and absence of smaller saccades. Furthermore, saccades of all amplitudes, including microsaccades, were strongly suppressed during exposure to the stimulus. These findings do not support an important function of the visual transients caused by microsaccades. Copyright © 2015 Elsevier Ltd. All rights reserved.

  14. Impairment of contrast sensitivity function (CSF) as a measure of disability glare.

    Science.gov (United States)

    Abrahamsson, M; Sjöstrand, J

    1986-07-01

    A method for quantitative measurements of disability glare in clinical practice is presented. Glare is induced by a circular fluorescent tube which surrounds a sinusoidal grating displayed on a monitor. The threshold contrast that is needed for detection of the grating is measured with and without presence of the glare light. This is repeated for several different spatial frequencies. The discrepancy between the contrast sensitivity function (CSF) obtained with and without glare light was used to calculate the glare score (n) as a measure of disability glare. This was done for normals and cataract patients. The results show that an increasing glare score is related to an increase in turbidity of the optic media, while visual acuity had a weak correlation to the glare score. We also studied the relation glare score versus luminance and found that normals had a glare score that was almost independent of luminance level, while the cataract patients had a marked decrease in glare sensitivity when the luminance decreased. Most patients had a glare score that corresponded to their glare problems. These findings indicate a potential for using this psychophysical disability glare test method in industry, transport, and clinical ophthalmology. Some sources of methodological error inherent in the test method are evaluated and discussed.

  15. Measuring streetscape complexity based on the statistics of local contrast and spatial frequency.

    Directory of Open Access Journals (Sweden)

    André Cavalcante

    Full Text Available Streetscapes are basic urban elements which play a major role in the livability of a city. The visual complexity of streetscapes is known to influence how people behave in such built spaces. However, how and which characteristics of a visual scene influence our perception of complexity have yet to be fully understood. This study proposes a method to evaluate the complexity perceived in streetscapes based on the statistics of local contrast and spatial frequency. Here, 74 streetscape images from four cities, including daytime and nighttime scenes, were ranked for complexity by 40 participants. Image processing was then used to locally segment contrast and spatial frequency in the streetscapes. The statistics of these characteristics were extracted and later combined to form a single objective measure. The direct use of statistics revealed structural or morphological patterns in streetscapes related to the perception of complexity. Furthermore, in comparison to conventional measures of visual complexity, the proposed objective measure exhibits a higher correlation with the opinion of the participants. Also, the performance of this method is more robust regarding different time scenarios.

  16. Threshold-dependent variability of coronary artery calcification measurements - implications for contrast-enhanced multi-detector row-computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Moselewski, Fabian [Division of Cardiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA (United States); Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA (United States); Ferencik, Maros [Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA (United States); Achenbach, Stephan [Division of Cardiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA (United States); Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA (United States); Department of Internal Medicine II (Cardiology), University of Erlangen (Germany); Abbara, Suhny [Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA (United States); Cury, Ricardo C. [Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA (United States); Booth, Sarah L. [Jean Mayer USDA Human Nutrition Research Center on Aging, 711 Washington St., Boston, MA 02114 (United States); Jang, Ik-Kyung [Division of Cardiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA (United States); Brady, Thomas J. [Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA (United States); Hoffmann, Udo [Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA (United States)]. E-mail: uhoffman@partners.org

    2006-03-15

    Introduction: The present study investigated the threshold-dependent variability of coronary artery calcification (CAC) measurements and the potential to quantify CAC in contrast-enhanced multi-detector row-computed tomography (MDCT). Methods: We compared the mean CT attenuation of CAC to luminal contrast enhancement of the coronary arteries in 30 patients (n = 30) undergoing standard coronary contrast-enhanced spiral MDCT. The modified Agatston score [AS], calcified plaque volume [CV], and mineral mass [MM] at four different thresholds (130, 200, 300, and 400 HU) were measured in 50 patients who underwent non-contrast-enhanced MDCT. Results: Mean CT attenuation of CAC was similar to the attenuation of the contrast-enhanced coronary lumen (CAC 297.1 {+-} 68.7 HU versus 295 {+-} 65 HU (p < 0.0001), respectively). Above a threshold of 300 HU CAC measurements significantly varied to standard measurements obtained at a threshold of 130 HU (p < 0.0001). The threshold-dependent variation of MM measurements was significantly smaller than for AS and CV (130 HU versus 400 HU: 63, 75, and 81, respectively; p < 0.001). These differences resulted in a change of age and gender based percentile category for AS in 78% of subjects. Discussion: We demonstrated that CAC measurements are threshold dependent with MM measurements having significantly less variation than AS or CV. Due to the similarity of mean CT attenuation of CAC and the contrast-enhanced coronary lumen accurate quantification of CAC may be difficult in standard coronary contrast-enhanced spiral MDCT.

  17. Tracer kinetic modelling of tumour angiogenesis based on dynamic contrast-enhanced CT and MRI measurements

    Energy Technology Data Exchange (ETDEWEB)

    Brix, Gunnar [Federal Office for Radiation Protection, Department of Medical and Occupational Radiation Protection, Oberschleissheim (Germany); Bundesamt fuer Strahlenschutz (BfS), Abteilung fuer medizinischen und beruflichen Strahlenschutz, Oberschleissheim (Germany); Griebel, Juergen [Federal Office for Radiation Protection, Department of Medical and Occupational Radiation Protection, Oberschleissheim (Germany); Kiessling, Fabian [RWTH-Aachen University, Department of Experimental Molecular Imaging, Aachen (Germany); Wenz, Frederik [University Medical Center Mannheim, University of Heidelberg, Department of Radiation Oncology, Mannheim (Germany)

    2010-08-15

    Technical developments in both magnetic resonance imaging (MRI) and computed tomography (CT) have helped to reduce scan times and expedited the development of dynamic contrast-enhanced (DCE) imaging techniques. Since the temporal change of the image signal following the administration of a diffusible, extracellular contrast agent (CA) is related to the local blood supply and the extravasation of the CA into the interstitial space, DCE imaging can be used to assess tissue microvasculature and microcirculation. It is the aim of this review to summarize the biophysical and tracer kinetic principles underlying this emerging imaging technique offering great potential for non-invasive characterization of tumour angiogenesis. In the first part, the relevant contrast mechanisms are presented that form the basis to relate signal variations measured by serial CT and MRI to local tissue concentrations of the administered CA. In the second part, the concepts most widely used for tracer kinetic modelling of concentration-time courses derived from measured DCE image data sets are described in a consistent and unified manner to highlight their particular structure and assumptions as well as the relationships among them. Finally, the concepts presented are exemplified by the analysis of representative DCE data as well as discussed with respect to present and future applications in cancer diagnosis and therapy. Depending on the specific protocol used for the acquisition of DCE image data and the particular model applied for tracer kinetic analysis of the derived concentration-time courses, different aspects of tumour angiogenesis can be quantified in terms of well-defined physiological tissue parameters. DCE imaging offers promising prospects for improved tumour diagnosis, individualization of cancer treatment as well as the evaluation of novel therapeutic concepts in preclinical and early-stage clinical trials. (orig.)

  18. Information and backaction due to phase contrast imaging measurements of cold atomic gases: beyond Gaussian states

    CERN Document Server

    Ilo-Okeke, Ebubechukwu O

    2016-01-01

    We further examine a theory of phase contrast imaging (PCI) of cold atomic gases, first introduced by us in Phys. Rev. Lett. {\\bf 112}, 233602 (2014). We model the PCI measurement by directly calculating the entangled state between the light and the atoms due to the ac Stark shift, which induces a conditional phase shift on the light depending upon the atomic state. By interfering the light that passes through the BEC with the original light, one can obtain information of the atomic state at a single shot level. We derive an exact expression for a measurement operator that embodies the information obtained from PCI, as well as the back-action on the atomic state. By the use of exact expressions for the measurement process, we go beyond the continuous variables approximation such that the non-Gaussian regime can be accessed for both the measured state and the post-measurement state. Features such as the photon probability density, signal, signal variance, Fisher information, error of the measurement, and the b...

  19. Changes over time of psychoacoustic outcome measurements are not a substitute for subjective outcome measurements in acute tinnitus.

    Science.gov (United States)

    Rabau, Sarah; Cox, Tony; Punte, Andrea Kleine; Waelkens, Brecht; Gilles, Annick; Wouters, Kristien; de Varebeke, Sebastien Janssens; Van de Heyning, Paul

    2015-03-01

    The aim of this study was to assess correlations between the changes over time of various tinnitus measurements. A longitudinal prospective study comparing two test moments was performed: before treatment and after 90 days. Tinnitus assessment consisted of psychoacoustic outcome measurements (minimal masking level and loudness matching at 1 kHz) and subjective outcome measurements (Tinnitus Impairment Questionnaire, Tinnitus Questionnaire and Numeric Rating Scale of loudness and annoyance). Additionally, the effect size was measured. 35 subjects were included in this study. The subjects had a permanent, non-pulsatile tinnitus acquired psychoacoustic outcome measurements and ∆subjective outcome measurements. The effect size showed that subjective outcome measurements were the most responsive to measure change in tinnitus complaints. We can conclude that psychoacoustic outcome measurements of tinnitus cannot substitute subjective outcome measurements in patients with acute tinnitus. The authors recommend subjective outcome measurements as primary outcome measurements in a clinical setting. In research, however, it is meaningful to quantify tinnitus in both ways.

  20. Localized measurement of short wavelength plasma fluctuations with the DIII-D phase contrast imaging diagnostic.

    Science.gov (United States)

    Dorris, J R; Rost, J C; Porkolab, M

    2009-02-01

    A novel rotating mask system has been designed and implemented on the DIII-D phase contrast imaging (PCI) diagnostic to produce the first spatially localized PCI measurements of a tokamak plasma. The localization technique makes use of the variation in the magnetic field component perpendicular to the viewing chord as a function of chord height. This new capability provides measurements in the range of 2measurements at a rate of 10 profiles/s. Calibration measurements show accurate characterization of the system transfer function making feasible a time dependent analysis that results in improved localization. Initial measurements show turbulence to peak near the plasma edge. This upgrade is part of a broader program to operate the DIII-D PCI at wave numbers up to 40 cm(-1) to probe electron scale turbulence in the plasma core.

  1. Protection of human subjects of biomedical research in the United States. A contrast with recent experience in the United Kingdom.

    Science.gov (United States)

    Levine, R J

    1988-01-01

    In the U.S., the development of extensive regulations for the protection of human subjects of research began in the 1960s and continued through the 1970s. The substance of these regulations reflects the American social and political climate of the time. There is a focus on rights--e.g., to be left alone, to be self-determining--reflected in elaborate requirements to assure the validity and documentation of informed consent. There is also a focus on systems of disinterested review and monitoring procedures to assure uniform adherence to the requirements of the regulations. To the extent that the U.S. has developed extensive regulations in this field, it may be viewed as more advanced than the U.K. And yet, it is apparent that there remain on both sides of the Atlantic very difficult and similar problems regarding the definition of responsible research. Such problems are illustrated by consideration of current controversies about the ethical justification of RCTs. There are some features of the U.S. regulatory system that I can commend to the attention of other nations as they develop policies for the protection of human research subjects. For example, a uniform requirement for informed consent and committee review appears to be responsive to some problems currently encountered in the conduct of RCTs in the U.K. A note of caution is in order, however. Some features of our regulatory policy and practices are excessively inflexible, wasteful of human resources, and occasionally counterproductive.

  2. Subjective Sleepiness and Sleep Quality in Adolescents are Related to Objective and Subjective Measures of School Performance

    OpenAIRE

    Boschloo, Annemarie; Krabbendam, Lydia; Dekker, Sanne; Lee, Nikki; De Groot, Renate; Jolles, Jelle

    2013-01-01

    This study investigated the relation between sleep and school performance in a large sample of 561 adolescents aged 11–18 years. Three subjective measures of sleep were used: sleepiness, sleep quality, and sleep duration. They were compared to three measures of school performance: objective school grades, self-reported school performance, and parent-reported school performance. Sleepiness – “I feel sleepy during the first hours at school” – appeared to predict both school grades and self-repo...

  3. Measurement of cerebral blood flow using phase contrast magnetic resonance imaging and duplex ultrasonography.

    Science.gov (United States)

    Khan, Muhammad Ayaz; Liu, Jie; Tarumi, Takashi; Lawley, Justin Stevan; Liu, Peiying; Zhu, David C; Lu, Hanzhang; Zhang, Rong

    2017-02-01

    Phase contrast magnetic resonance imaging (PC-MRI) and color-coded duplex ultrasonography (CDUS) are commonly used for measuring cerebral blood flow in the internal carotid (ICA) and vertebral arteries. However, agreement between the two methods has been controversial. Recent development of high spatial and temporal resolution blood vessel wall edge-detection and wall-tracking methods with CDUS increased the accuracy and reliability of blood vessel diameter, hence cerebral blood flow measurement. The aim of this study was to compare the improved CDUS method with 3 T PC-MRI for cerebral blood flow measurements. We found that cerebral blood flow velocity measured in the ICA was lower using PC-MRI than CDUS (left ICA: PC-MRI, 18.0 ± 4.2 vs. CDUS, 25.6 ± 8.6 cm/s; right ICA: PC-MRI, 18.5 ± 4.8 vs. CDUS, 26.6 ± 6.7 cm/s, both p flow velocity measured in the left vertebral artery with PC-MRI was also lower than CDUS, but no differences in vertebral artery diameter were observed between the methods. Dynamic changes and/or intrinsic physiological fluctuations may have caused these differences in vessel diameter and velocity measurements between the methods. However, estimation of volumetric cerebral blood flow was similar and correlated between the methods despite the presence of large individual differences. These findings support the use of CDUS for cerebral blood flow measurements in the ICA and vertebral artery.

  4. Identification of ultrasound contrast agent dilution systems for ejection fraction measurements.

    Science.gov (United States)

    Mischi, Massimo; Jansen, Annemieke H M; Kalker, Antonius A C M; Korsten, Hendrikus H M

    2005-03-01

    Left ventricular ejection fraction is an important cardiac-efficiency measure. Standard estimations are based on geometric analysis and modeling; they require time and experienced cardiologists. Alternative methods make use of indicator dilutions, but they are invasive due to the need for catheterization. This study presents a new minimally invasive indicator dilution technique for ejection fraction quantification. It is based on a peripheral injection of an ultrasound contrast agent bolus. Left atrium and left ventricle acoustic intensities are recorded versus time by transthoracic echocardiography. The measured curves are corrected for attenuation distortion and processed by an adaptive Wiener deconvolution algorithm for the estimation of the left ventricle impulse response, which is interpolated by a monocompartment exponential model for the ejection fraction assessment. This technique measures forward ejection fraction, which excludes regurgitant volumes. The feasibility of the method was tested on a group of 20 patients with left ventricular ejection fractions going from 10% to 70%. The results are promising and show a 0.93 correlation coefficient with echographic bi-plane ejection fraction measurements. A more extensive validation as well as an investigation on the method applicability for valve insufficiency and right ventricular ejection fraction quantification will be an object of future study.

  5. Enhanced tumor contrast during breast lumpectomy provided by independent component analysis of localized reflectance measures

    Science.gov (United States)

    Eguizabal, Alma; Laughney, Ashley M.; Garcia Allende, Pilar Beatriz; Krishnaswamy, Venkataramanan; Wells, Wendy A.; Paulsen, Keith D.; Pogue, Brian W.; Lopez-Higuera, Jose M.; Conde, Olga M.

    2012-03-01

    A spectral analysis technique to enhance tumor contrast during breast conserving surgery is proposed. A set of 29 surgically-excised breast tissues have been imaged in local reflectance geometry. Measures of broadband reflectance are directly analyzed using Principle Component Analysis (PCA), on a per sample basis, to extract areas of maximal spectral variation. A dynamic selection threshold has been applied to obtain the final number of principal components, accounting for inter-patient variability. A blind separation technique based on Independent Component Analysis (ICA) is then applied to extract diagnostically powerful results. ICA application reveals that the behavior of one independent component highly correlates with the pathologic diagnosis and it surpasses the contrast obtained using empirical models. Moreover, blind detection characteristics (no training, no comparisons with training reference data) and no need for parameterization makes the automated diagnosis simple and time efficient, favoring its translation to the clinical practice. Correlation coefficient with model-based results up to 0.91 has been achieved.

  6. Monitoring the athlete training response: subjective self-reported measures trump commonly used objective measures: a systematic review.

    Science.gov (United States)

    Saw, Anna E; Main, Luana C; Gastin, Paul B

    2016-03-01

    Monitoring athlete well-being is essential to guide training and to detect any progression towards negative health outcomes and associated poor performance. Objective (performance, physiological, biochemical) and subjective measures are all options for athlete monitoring. We systematically reviewed objective and subjective measures of athlete well-being. Objective measures, including those taken at rest (eg, blood markers, heart rate) and during exercise (eg, oxygen consumption, heart rate response), were compared against subjective measures (eg, mood, perceived stress). All measures were also evaluated for their response to acute and chronic training load. The databases Academic search complete, MEDLINE, PsycINFO, SPORTDiscus and PubMed were searched in May 2014. Fifty-six original studies reported concurrent subjective and objective measures of athlete well-being. The quality and strength of findings of each study were evaluated to determine overall levels of evidence. Subjective and objective measures of athlete well-being generally did not correlate. Subjective measures reflected acute and chronic training loads with superior sensitivity and consistency than objective measures. Subjective well-being was typically impaired with an acute increase in training load, and also with chronic training, while an acute decrease in training load improved subjective well-being. This review provides further support for practitioners to use subjective measures to monitor changes in athlete well-being in response to training. Subjective measures may stand alone, or be incorporated into a mixed methods approach to athlete monitoring, as is current practice in many sport settings. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  7. Magnetic resonance measurement of blood and CSF flow rates with phase contrast--normal values, repeatability and CO2 reactivity.

    Science.gov (United States)

    Piechnik, Stefan K; Summers, Paul E; Jezzard, Peter; Byrne, James V

    2008-01-01

    Similarity in flow pulsatility has been proposed as a basis for semi-automated segmentation of vessel lumens for MR-based flow measurement, but re-examinations of salient aspects of the methodology have not been widely reported. 12 normal control subjects underwent repeated (3*Baseline+1*5%CO2) phase contrast measurements of CSF flow through the cerebral aqueduct and foramen magnum, and CBF through the 6 large cranial vessels at the level of the 1st vertebra. Average flows were calculated for regions temporally correlated (0.3 < or = Rthreshold < or = 0.95) to user defined seed points and their 3 x 3 neighbours. Arterial CBF averaged 710ml/min, with low variability (+/- 4%/17%, intra-individual/group CV respectively) and was the only flow to respond significantly to 5%/mmHg CO2. Venous outflow was much smaller (298ml/min +/- 10%/ 72%), possibly due to the weak venous pulse and variable venous anatomy. Average CSF flows exceeded the classical 0.4ml/min CSF production rate and were highly variable--aqueduct: 0.6ml/min (+/- 50%/93%), foramen magnum: -2.7ml/min (+/- 158%/226%). This preliminary analysis identified procedural steps that can improve the accuracy and repeatability of MR flow measurements, but the process remains user-dependent for the weakly pulsatile foramen magnum CSF and venous flows where variability remains a significant confound even to relatively large perturbations such as CO2 administration.

  8. Dose and image quality measurements for contrast-enhanced dual energy mammography systems

    Science.gov (United States)

    Oduko, J. M.; Homolka, P.; Jones, V.; Whitwam, D.

    2015-03-01

    The results of patient dose surveys of two contrast-enhanced dual energy mammography systems are presented, showing mean glandular doses for both low and high energy components of the exposures. For one system the distribution of doses is of an unusual pattern, very different from that normally measured in patient dose surveys. The contribution of the high energy component of the exposure to the total is shown to be about 20% of that of the low energy component for this system. It is about 33% for the other system, for which the distribution of doses is similar to previously published surveys . A phantom containing disks with a range of different iodine content was used, with tissue-equivalent materials, to investigate the properties of one dual energy system. The iodine signal difference to noise ratio is suggested as a measure of image quality. It was found to remain practically constant as phantom thickness was varied, and increased only slowly (with a power relationship) as air kerma increased. Other measurements showed good reproducibility of the iodine signal difference, and that it was proportional to iodine concentration in the phantom. The iodine signal difference was found to be practically the same for a wide range of phantom thickness and glandularity.

  9. Of MOS and men : Bridging the gap between objective and subjective quality measurements in mobile TV

    NARCIS (Netherlands)

    De Koning, T.C.M.; Veldhoven, P.; Knoche, H.; Kooij, R.E.

    2007-01-01

    In this paper we explore the relation between subjective and objective measures of video quality. We computed objective MOS values from video clips using the video quality measuring tool VQM and compared it to the clips’ subjective Acceptability scores. Using the ITU defined mapping (M2G) from MOS

  10. Time-course analysis of stretch reflexes in hemiparetic subjects using an on-line spasticity measurement system.

    Science.gov (United States)

    Ju, M S; Chen, J J; Lee, H M; Lin, T S; Lin, C C; Huang, Y Z

    2000-02-01

    Spasticity after a stroke is usually assessed in a score form by subjectively determining the resistance of a joint to an externally imposed passive movement. This work presents a spasticity measurement system for on-line quantifying the stretch reflex of paretic limbs. Four different constant stretch velocities in a ramp-and-hold mode are used to elicit the stretch reflex of the elbow joint in spastic subjects. The subjects are tested at supine position with the upper limb stretched towards the ground, in contrast with the horizontally stretched movement used in other studies. By subtracting the baseline torque, reflex torque measured at a selected low stretch velocity of 5 deg/sec, the influence of gravity torque and inertial in vertical stretching mode can be minimized. The averaged speed-dependent reflex torque (ASRT), defined as the measured torque deviated from the baseline torque, is used for quantifying the spastic hypertonia. Four subjects having incurred cerebrovascular accident (CVA) are recruited for time-course study in which the measurements are taken at 72 hours, one week, one month, three months, and six months after onset of stroke. During the development of spasticity, the changes of ASRT and velocity sensitivity of ASRT of the involved and the intact elbow joints are discussed.

  11. Comportamento da dose glandular versus contraste do objeto em mamografia: determinação de formalismo semi-empírico para diferentes combinações alvo-filtro Behavior of subject contrast versus glandular dose in mammography: determination of a semi-empirical formalism for different target-filter combinations

    Directory of Open Access Journals (Sweden)

    Gabriela Hoff

    2006-06-01

    Full Text Available OBJETIVO: Verificar o efeito da mudança no contraste do objeto, tempo de exposição e dose de radiação quando diferentes espessuras de filtração de molibdênio (Mo e ródio (Rh são empregadas em mamógrafos. MATERIAIS E MÉTODOS: Realizaram-se medidas da exposição na entrada da pele com uma câmara de ionização para diferentes espessuras para os filtros de Mo e Rh. Para determinar a dose glandular média foi utilizado simulador de BR12 (50% tecido adiposo e 50% tecido glandular de diferentes espessuras (4 cm e 8 cm. Energias na faixa de 24 kVp a 34 kVp foram empregadas e filmes Kodak MinR 2000 foram utilizados. RESULTADOS: Os resultados evidenciaram dados de contraste do objeto, dose glandular e tempo de exposição para diferentes espessuras de filtros adicionais e diferentes tensões. Esses dados indicaram aumento nos valores de contraste do objeto e tempo de exposição, com o aumento da espessura dos filtros. A dose glandular apresentou comportamento com diferentes tendências para cada caso analisado. Equações foram definidas para possibilitar a estimativa do contraste do objeto, dose glandular e tempo de exposição para os casos estudados. CONCLUSÃO: Os resultados possibilitaram a estimativa de equações que auxiliam na verificação do comportamento do contraste do objeto e da dose glandular para simuladores com espessura de 4 cm e 8 cm e para os filtros de Rh e Mo. Dessa forma, torna-se possível estimar a figura de mérito (razão entre o contraste do objeto e a dose glandular, podendo auxiliar na análise da relação risco-benefício dos casos estudados.OBJECTIVE: Our purpose was to verify the effect of changes in subject contrast, exposure time and radiation dose when different thicknesses of molybdenum (Mo and rhodium (Rh filters are used in mammography equipments. MATERIALS AND METHODS: Entrance skin exposure measurements were performed with an ionization chamber for different thicknesses of Mo and Rh filters

  12. E-MODULE DEVELOPMENT FOR THE SUBJECT OF MEASURING INSTRUMENTS AND MEASUREMENT IN ELECTRONICS ENGINEERING EDUCATION

    Directory of Open Access Journals (Sweden)

    Nuryake Fajaryati

    2016-09-01

    Full Text Available This study aims to develop an e-module as a medium of learning for the practice course of Measuring Instruments and Measurement in the Department of Electronics Engineering Education of Yogyakarta State University and to determine the feasibility of the e-module. This study employed a method of research and development. The development process was conducted through four phases by using the model of Lee and Owens which consisted of analysis phase, design phase, developing and implementation phase, as well as evaluation phase.The evaluation was conducted in several stages. Firstly, an alpha test for product validation was conducted by the experts on material and media. After that, a beta test was conducted by testing the product in small group users. The subjects of this study were the students of Electronics Engineering. The instruments used to collect the data were a validation sheet and questionnaires. The results of qualitative data were then modified into quantitative data with a range of 1 to 5, then they were converted with a rating scale to determine the feasibility of the medium. The results showed that based on the alpha test, the medium was in a very high quality. Meanwhile, in the beta test of the instructional aspect, in terms of material and evaluation and the multimedia aspect the e-module was respectively considered feasible and quite feasible. The four indicators namely text, image, animation and video were all generally considered feasible. In terms of usage aspect, the e-module was considered feasible where its two indicators, namely instructions and navigation, were generally regarded as very feasible by all respondents.

  13. Error analysis of cine phase contrast MRI velocity measurements used for strain calculation.

    Science.gov (United States)

    Jensen, Elisabeth R; Morrow, Duane A; Felmlee, Joel P; Odegard, Gregory M; Kaufman, Kenton R

    2015-01-02

    Cine Phase Contrast (CPC) MRI offers unique insight into localized skeletal muscle behavior by providing the ability to quantify muscle strain distribution during cyclic motion. Muscle strain is obtained by temporally integrating and spatially differentiating CPC-encoded velocity. The aim of this study was to quantify CPC measurement accuracy and precision and to describe error propagation into displacement and strain. Using an MRI-compatible jig to move a B-gel phantom within a 1.5 T MRI bore, CPC-encoded velocities were collected. The three orthogonal encoding gradients (through plane, frequency, and phase) were evaluated independently in post-processing. Two systematic error types were corrected: eddy current-induced bias and calibration-type error. Measurement accuracy and precision were quantified before and after removal of systematic error. Through plane- and frequency-encoded data accuracy were within 0.4 mm/s after removal of systematic error - a 70% improvement over the raw data. Corrected phase-encoded data accuracy was within 1.3 mm/s. Measured random error was between 1 to 1.4 mm/s, which followed the theoretical prediction. Propagation of random measurement error into displacement and strain was found to depend on the number of tracked time segments, time segment duration, mesh size, and dimensional order. To verify this, theoretical predictions were compared to experimentally calculated displacement and strain error. For the parameters tested, experimental and theoretical results aligned well. Random strain error approximately halved with a two-fold mesh size increase, as predicted. Displacement and strain accuracy were within 2.6 mm and 3.3%, respectively. These results can be used to predict the accuracy and precision of displacement and strain in user-specific applications. Copyright © 2014 Elsevier Ltd. All rights reserved.

  14. On the achievable field sensitivity of a segmented annular detector for differential phase contrast measurements.

    Science.gov (United States)

    Schwarzhuber, Felix; Melzl, Peter; Zweck, Josef

    2017-06-01

    Differential phase contrast microscopy measures minute deflections of the electron probe due to electric and/or magnetic fields, using a position sensitive device. Although recently, pixelated detectors have become available which also serve as a position sensitive device, the most frequently used detector is a four-segmented annular semiconducting detector ring (or variations thereof), where the difference signals of opposing detector elements represent the components of the deflection vector. This deflection vector can be used directly to quantitatively determine the deflecting field, provided the specimen's thickness is known. While there exist many measurements of both electric and magnetic fields, even at an atomic level, until now the question of the smallest clearly resolvable field value for this detector has not yet been answered. This paper treats the problem theoretically first, leading to a calibration factor κ which depends solely on simple, experimentally accessible parameters and relates the deflecting field to the measured deflection vector. In a second step, the calibration factor for our combination of microscope and detector is determined experimentally for various combinations of camera length, condenser aperture and spot size to determine the optimum setup. From this optimized condition we determine the minimum change in field which leads to a clearly measurable signal change for both HMSTEM and LMSTEM operation. A strategy is described which allows the experimenter to choose the setup giving the highest field sensitivity. Quantification problems due to scattering processes in the specimen are addressed and ways are shown to choose a setup which is less sensitive to these artefacts. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. On the achievable field sensitivity of a segmented annular detector for differential phase contrast measurements

    Energy Technology Data Exchange (ETDEWEB)

    Schwarzhuber, Felix, E-mail: felix.schwarzhuber@ur.de; Melzl, Peter; Zweck, Josef

    2017-06-15

    Highlights: • Practical guide to calibrate a DPC setup considering geometrical parameters. • Optimizing the field sensitivity of a segmented annular DPC detector. • Determination of maximum electric and magnetic field sensitivity of a DPC setup. - Abstract: Differential phase contrast microscopy measures minute deflections of the electron probe due to electric and/or magnetic fields, using a position sensitive device. Although recently, pixelated detectors have become available which also serve as a position sensitive device, the most frequently used detector is a four-segmented annular semiconducting detector ring (or variations thereof), where the difference signals of opposing detector elements represent the components of the deflection vector. This deflection vector can be used directly to quantitatively determine the deflecting field, provided the specimen’s thickness is known. While there exist many measurements of both electric and magnetic fields, even at an atomic level, until now the question of the smallest clearly resolvable field value for this detector has not yet been answered. This paper treats the problem theoretically first, leading to a calibration factor κ which depends solely on simple, experimentally accessible parameters and relates the deflecting field to the measured deflection vector. In a second step, the calibration factor for our combination of microscope and detector is determined experimentally for various combinations of camera length, condenser aperture and spot size to determine the optimum setup. From this optimized condition we determine the minimum change in field which leads to a clearly measurable signal change for both HMSTEM and LMSTEM operation. A strategy is described which allows the experimenter to choose the setup giving the highest field sensitivity. Quantification problems due to scattering processes in the specimen are addressed and ways are shown to choose a setup which is less sensitive to these artefacts.

  16. Measuring Methods of Luminance Contrast between Tactile Walking Surface Indicators and Their Surrounding or Adjacent Surfaces at Railway Stations

    National Research Council Canada - National Science Library

    OHNO, Hisato; SUZUKI, Ayako; AKIU, Naohiro

    2017-01-01

    ... criteria in real environments such as railway stations. In this paper, the authors propose measuring methods of the luminance contrast around TWSIs, taking the environmental characteristics of railway stations into consideration.

  17. Subjective sleepiness and sleep quality in adolescents are related to objective and subjective measures of school performance

    Directory of Open Access Journals (Sweden)

    Annemarie eBoschloo

    2013-02-01

    Full Text Available This study investigated the relation between sleep and school performance in a large sample of 561 adolescents aged 11-18 years. Three subjective measures of sleep were used: sleepiness, sleep quality and sleep duration. They were compared to three measures of school performance: objective school grades, self-reported school performance, and parent-reported school performance. Sleepiness – ‘I feel sleepy during the first hours at school’ – appeared to predict both school grades and self-reported school performance. Sleep quality on the other hand – as a measure of (uninterrupted sleep and/or problems falling asleep or waking up – predicted parent-reported school performance. Self- and parent-reported school performance correlated only moderately with school grades. So it turns out that the measures used to measure either sleep or school performance impacts whether or not a relation is found. Further research on sleep and school performance should take this into account. The findings do underscore the notion that sleep in adolescence can be important for learning. They are compatible with the hypothesis that a reduced sleep quality can give rise to sleepiness in the first hours at school which results in lower school performance. This notion could have applied value in counseling adolescents and their parents in changing adolescents’ sleep behavior.

  18. Subjective Sleepiness and Sleep Quality in Adolescents are Related to Objective and Subjective Measures of School Performance.

    Science.gov (United States)

    Boschloo, Annemarie; Krabbendam, Lydia; Dekker, Sanne; Lee, Nikki; de Groot, Renate; Jolles, Jelle

    2013-01-01

    This study investigated the relation between sleep and school performance in a large sample of 561 adolescents aged 11-18 years. Three subjective measures of sleep were used: sleepiness, sleep quality, and sleep duration. They were compared to three measures of school performance: objective school grades, self-reported school performance, and parent-reported school performance. Sleepiness - "I feel sleepy during the first hours at school" - appeared to predict both school grades and self-reported school performance. Sleep quality on the other hand - as a measure of (un)interrupted sleep and/or problems falling asleep or waking up - predicted parent-reported school performance. Self- and parent-reported school performance correlated only moderately with school grades. So it turns out that the measures used to measure either sleep or school performance impacts whether or not a relation is found. Further research on sleep and school performance should take this into account. The findings do underscore the notion that sleep in adolescence can be important for learning. They are compatible with the hypothesis that a reduced sleep quality can give rise to sleepiness in the first hours at school which results in lower school performance. This notion could have applied value in counseling adolescents and their parents in changing adolescents' sleep behavior.

  19. Effect of sport-tinted contact lenses for contrast enhancement on retinal straylight measurements.

    Science.gov (United States)

    Cerviño, Alejandro; Gonzalez-Meijome, Jose M; Linhares, João M M; Hosking, Sarah L; Montes-Mico, Robert

    2008-03-01

    To investigate the effect of two tinted contact lenses (CL) designed for outdoor sports activity on the psychometric determination of retinal straylight using the compensation comparison method. Thirteen emmetropic subjects were randomly fitted with two different tinted Nike Maxsight (Bausch & Lomb, Rochester, NY, USA) CL in one eye, while the contralateral eye was fitted with a clear lens made of the same material (Optima 38, Bausch & Lomb). Three valid straylight measurements were taken on each eye before and a few minutes after lens insertion, when lens stabilization had occurred. The subjects' mean straylight values were 0.90 +/- 0.09 at baseline and 0.95 +/- 0.10 with the clear Optima 38 CL. Straylight values were 0.97 +/- 0.10 and 1.0 +/- 0.10 log units with the amber and grey-green tinted CL, respectively. Differences in straylight between baseline (without CL) and with the clear CL in place were neither statistically significant (p = 0.066) nor was there a significant difference between baseline and the amber CL (p = 0.052). However, the grey-green CL showed a statistically significant difference from baseline (p = 0.006). Differences in straylight with the clear CL compared with the grey-green CL were also statistically different from zero (p = 0.002) showing an increased straylight value for the tinted CL. These differences were variable, but consistent for each subject, thus those showing higher or lower changes with one tinted lens tended to show the same trend with the second lens (r(2) = 0.736). Despite increases having been found in straylight values with tinted contact lenses, those changes are not likely to induce clinically significant changes in visual function under photopic conditions, even for the grey-green CL, which seems to increase straylight values more significantly than the amber CL. This difference between the tinted CL could suggest a wavelength dependence of straylight values, although this should be investigated further by

  20. Measuring organizational performance in the hospital industry: an exploratory comparison of objective and subjective methods.

    Science.gov (United States)

    McCracken, M J; McIlwain, T F; Fottler, M D

    2001-11-01

    One of the major challenges facing health services management researchers is the measurement of various aspects of organizational performance. This challenge is exacerbated by a reluctance of many healthcare organizations to share data with researchers because of a fear of competitor access to these data. Even where objective, reliable and valid measures of organizational performance are available, typically they are available only in aggregate form, rather than for individual organizations. In response to these constraints, researchers have used subjective measures of performance often based on the perception of key executives. This research compares the subjective perceptions of hospital executives to the objective financial performance data of 60 hospitals. While the correlations between the subjective and objective measures vary, return of assets (ROA) and operating margin are the most valid subjective financial measures of hospital performance. Implications for future research are discussed.

  1. SEM technique for imaging and measuring electronic transport in nanocomposites based on electric field induced contrast

    Science.gov (United States)

    Jesse, Stephen [Knoxville, TN; Geohegan, David B [Knoxville, TN; Guillorn, Michael [Brooktondale, NY

    2009-02-17

    Methods and apparatus are described for SEM imaging and measuring electronic transport in nanocomposites based on electric field induced contrast. A method includes mounting a sample onto a sample holder, the sample including a sample material; wire bonding leads from the sample holder onto the sample; placing the sample holder in a vacuum chamber of a scanning electron microscope; connecting leads from the sample holder to a power source located outside the vacuum chamber; controlling secondary electron emission from the sample by applying a predetermined voltage to the sample through the leads; and generating an image of the secondary electron emission from the sample. An apparatus includes a sample holder for a scanning electron microscope having an electrical interconnect and leads on top of the sample holder electrically connected to the electrical interconnect; a power source and a controller connected to the electrical interconnect for applying voltage to the sample holder to control the secondary electron emission from a sample mounted on the sample holder; and a computer coupled to a secondary electron detector to generate images of the secondary electron emission from the sample.

  2. Phase Contrast Imaging Measurements of Edge Turbulence Across an H-mode Transition

    Science.gov (United States)

    Rost, J. C.; Marinoni, A.; Porkolab, M.; Burrell, K. H.

    2013-10-01

    The Phase Contrast Imaging (PCI) diagnostic on DIII-D provides a line-integrated measurement of density fluctuations. Analysis of previous PCI data taken during QH mode plasmas has revealed turbulence with short radial wavelengths and high frequencies which is generated by the well in the radial electric field Er. Application of these results allows us to study the rapid evolution in turbulence at an L-H transition. The dominant effect of the L-H transition on turbulence is a 70% drop in fluctuation amplitude. However high frequency fluctuations are seen to arise on the same time scale as the L-H transition (i.e. a few ms). Interpretation of the 2d spectrum S (k , f) of the PCI data of the line-integrated fluctuation, especially the Doppler shift and the ratio S (kpci / S (-kpci) , indicates that the high frequency fluctuations are located on the inner edge of the Er well. There is in addition a region of turbulence the PCI detects which is located outside the minimum of the Er well. This ongoing work will provide quantitative information on the evolution of the Er well at high time resolution across the L-H transition, important to understanding the interaction between turbulence and flow shear at the H-mode transition. Work supported by the US Department of Energy under DE-FG02-94ER54235 and DE-FC02-04ER54698.

  3. Measuring Plasticity with Orientation Contrast Microscopy in Aluminium 6061-T4

    NARCIS (Netherlands)

    Ghodrat, S.; Riemslag, A.C.; Kestens, L.A.I.

    2017-01-01

    Orientation contrast microscopy (i.e., electron backscattered diffraction, EBSD) was employed to monitor the plastic strain in loaded tensile samples of aluminium alloy Al6061 in T4 condition. The kernel average misorientation (KAM) is known to be an appropriate parameter in orientation contrast

  4. Modeling ultrasound contrast measurement of blood flow and perfusion in biological tissue.

    NARCIS (Netherlands)

    Thijssen, J.M.; Korte, C.L. de

    2005-01-01

    The aim of this paper was to obtain a parametric description of ultrasound (US) contrast dilution curves obtained in piglet brain after a bolus injection of contrast agent (Sonovue). Several models for so-called dye-dilution curves were considered, and a choice for the gamma probability density

  5. Optical discrimination of surface reflection from volume backscattering in speckle contrast for skin roughness measurements

    Science.gov (United States)

    Tchvialeva, Lioudmila; Zeng, Haishan; Markhvida, Igor; Dhadwal, Gurbir; McLean, Lianne; McLean, David I.; Lui, Harvey; Lee, Tim K.

    2009-02-01

    Background: The intermixing of light reflected from tissue surface and scattered from tissue volume complicates skin surface roughness assessment by laser speckle technique, a non-invasive optical method based on the analysis of the contrast of a speckle pattern. Objective: In this study we investigated optical discrimination methods to separate the two contributions in a speckle pattern. Methods: Three discrimination methods, spatial, polarization and spectral filtering, were implemented to suppress light from skin internal volume in a laser speckle device. In order to determine the effectiveness of the discrimination methods, speckle patterns were obtained from healthy volunteers, and polychromatic speckle contrast was computed before and after each filtering procedure. Results: Speckle contrast increased after discrimination filtering. A simple formula was derived to calculate the speckle contrast associated with light scattered from the skin surface. This corrected speckle contrast was proposed to be used for skin roughness assessment.

  6. Schrodinger's Cat: Empirical Research into the Radical Subjective solution of the Measurement problem.

    NARCIS (Netherlands)

    Bierman, D.; Whitmarsh, S.

    2007-01-01

    Schrodinger's Cat: Empirical research into the radical subjective solution of the measurement problem Dick J. Bierman & Stephen Whitmarsh The most controversial of all solutions of the measurement problem holds that a measurement is not completed until a conscious observation is made. In other

  7. THE SYSTEM OF STATISTICAL OBJECTIVE AND SUBJECTIVE INDICATORS OF MEASURING QUALITY OF LIFE

    OpenAIRE

    I. Romaniuk

    2015-01-01

    This article examines approaches to defining and measuring quality of life. Each approach to measuring the quality of life contains information that is not contained in the other measures. It describes the economic, subjective and social indicators. The strengths and weaknesses of those indicators are also analyzed.

  8. Differences between Subjective Balanced Occlusion and Measurements Reported With T-Scan III

    Directory of Open Access Journals (Sweden)

    Zana Lila-Krasniqi

    2017-08-01

    CONCLUSION: In our study, it was concluded that there were statistically significant differences of balanced occlusion in all three groups. Also it was concluded that subjective data are not exact with measurements reported with electronic device T-scan III.

  9. The psychophysics of workload - A second look at the relationship between subjective measures and performance

    Science.gov (United States)

    Gopher, D.; Chillag, N.; Arzi, N.

    1985-01-01

    Load estimates based upon subjective and performance indices were compared for subjects performing size matching and letter typing tasks under 6 levels of priorities, in single and dual task conditions. Each half of the group used a different task as reference in their subjective judgement. The results are interpreted to indicate that subjective measures are especially sensitive to voluntary allocation of attention and to the load on working memory. Association with performance is expected whenever these two factors are main determinants of performance efficiency, otherwise the two are likely to dissociate.

  10. Pacientes com depressão maior têm menor sensibilidade a contraste visual que indivíduos saudáveis Patients with major depression have visual contrast sensitivity less than healthy subjects

    Directory of Open Access Journals (Sweden)

    Renata Maria Toscano Barreto Lyra Nogueira

    2012-04-01

    Full Text Available O objetivo foi medir a sensibilidade ao contraste, SC, visual de grades senoidais circulares concêntricas com frequências espaciais de 0,25; 4 e 8 cpg, ciclos por grau de ângulo visual, em adultos saudáveis e com depressão maior. Foram estimadas a SC de 20 participantes, 10 saudáveis e 10 participantes com depressão maior, utilizando o método psicofísico da escolha forçada e luminância média de 0,7 cd/m². Todos os participantes apresentavam acuidade visual normal ou corrigida e estavam livres de doenças identificáveis. Os resultados mostraram que a SC visual máxima ocorreu na faixa de 0,25 cpg para os dois grupos. Os resultados demonstraram ainda que a SC visual dos participantes com depressão maior foi mais baixa do que a dos participantes saudáveis (p The aim of this study was to measure visual contrast sensitivity, CS, for concentric circular sine-wave gratings with spatial frequencies of 0.25, 4 and 8 cpd, cycles per degree of visual angle, in adults without and with major depression disorder. We measured the visual CS for 20 participants, ten without and ten with major depression disorder medicated, using a temporal two-alternative forced-choice psychophysical method with mean luminance of 0.7 cd/m². All volunteers were free from identifiable ocular disease and had normal acuity. The results showed maximum contrast sensitivity to spatial frequency occurred in the range of 0.25 cpd for both groups. The results also showed that the visual CS for major depression was lower than those of adults without depression (p < 0.05. These results showed alterations in the visual perception related the major depression.

  11. What Do Contrast Threshold Equivalent Noise Studies Actually Measure? Noise vs. Nonlinearity in Different Masking Paradigms.

    Directory of Open Access Journals (Sweden)

    Alex S Baldwin

    Full Text Available The internal noise present in a linear system can be quantified by the equivalent noise method. By measuring the effect that applying external noise to the system's input has on its output one can estimate the variance of this internal noise. By applying this simple "linear amplifier" model to the human visual system, one can entirely explain an observer's detection performance by a combination of the internal noise variance and their efficiency relative to an ideal observer. Studies using this method rely on two crucial factors: firstly that the external noise in their stimuli behaves like the visual system's internal noise in the dimension of interest, and secondly that the assumptions underlying their model are correct (e.g. linearity. Here we explore the effects of these two factors while applying the equivalent noise method to investigate the contrast sensitivity function (CSF. We compare the results at 0.5 and 6 c/deg from the equivalent noise method against those we would expect based on pedestal masking data collected from the same observers. We find that the loss of sensitivity with increasing spatial frequency results from changes in the saturation constant of the gain control nonlinearity, and that this only masquerades as a change in internal noise under the equivalent noise method. Part of the effect we find can be attributed to the optical transfer function of the eye. The remainder can be explained by either changes in effective input gain, divisive suppression, or a combination of the two. Given these effects the efficiency of our observers approaches the ideal level. We show the importance of considering these factors in equivalent noise studies.

  12. Differences in quantitative methods for measuring subjective cognitive decline - results from a prospective memory clinic study

    DEFF Research Database (Denmark)

    Vogel, Asmus; Salem, Lise Cronberg; Andersen, Birgitte Bo

    2016-01-01

    decline. Depression scores were significantly correlated to both scales measuring subjective decline. Linear regression models showed that age did not have a significant contribution to the variance in subjective memory beyond that of depressive symptoms. CONCLUSIONS: Measures for subjective cognitive......BACKGROUND: Cognitive complaints occur frequently in elderly people and may be a risk factor for dementia and cognitive decline. Results from studies on subjective cognitive decline are difficult to compare due to variability in assessment methods, and little is known about how different methods...... influence reports of cognitive decline. METHODS: The Subjective Memory Complaints Scale (SMC) and The Memory Complaint Questionnaire (MAC-Q) were applied in 121 mixed memory clinic patients with mild cognitive symptoms (mean MMSE = 26.8, SD 2.7). The scales were applied independently and raters were blinded...

  13. Biochemical and cardiovascular measures in subjects with noise-induced hearing loss

    Energy Technology Data Exchange (ETDEWEB)

    Gold, S.; Haran, I.; Attias, J.; Shapira, I.; Shahar, A. (Institute for Noise Hazards Research, Ramat Gan (Israel))

    1989-11-01

    Reports on a potential relationship between noise-induced hearing loss (NIHL) and cardiovascular as well as biochemical measures are controversial. This study compares the means of certain cardiovascular and biochemical measures in subjects with NIHL with those in subjects exposed to similar occupational noise, but demonstrating normal hearing. This might indicate certain predisposing factors for NIHL. Eight hundred noise-exposed subjects were divided into two age-matched hearing groups (NIHL and normal hearing). The results showed that the mean values of all the variables examined in both hearing groups were within the normal range. No significant differences were found between the two groups in terms of the distribution of subjects for the indices measured.

  14. Correlation of subjective slipperiness judgements with quantitative COF (Coefficient Of Friction) measurements for structural steel

    Science.gov (United States)

    Purswell, Jerry L.; Schlegel, Robert E.

    1988-06-01

    When there is no simple or accurate procedure for measuring the coefficient of friction (COF) at a job site, workers and/or supervisors involved must make subjective judgments about the slipperiness of the walking and climbing surfaces and in turn decide whether the surface presents a safe or an unsafe condition for work. This project was designed to determine whether these subjective judgment calls did in fact agree with the COF measurements obtained using a mechanical device. It was noted that the coatings chosen for study were subject to a polishing factor by the boot soles during the trials, causing the COF values to become lower as the trials continued. Poor correlation was obtained between subjective ratings of slipperiness and the COF values measured before the trials began. A relatively high correlation was obtained between subjective ratings and the COF values measured after the trials had been completed. A difference was noted in the subjective ratings for the effects of water on a coating for column climbing, but not for walking a beam, suggesting the effects of water on a coating are related to the type of task being performed in steel erection. An increase in the measured COF was noted for all of the coatings when they were wet as compared to the dry condition. The importance of clean shoe soles was clearly demonstrated.

  15. Subjective well-being in schizophrenia as measured with the Subjective Well-Being under Neuroleptic Treatment scale : a review

    NARCIS (Netherlands)

    Vothknecht, Sylke; Schoevers, Robert A.; de Haan, Lieuwe

    Objective: The Subjective Well-being under Neuroleptic Treatment scale (SWN) is the most widely used self-rating scale in recent research of subjective well-being in schizophrenia. We reviewed all available publications on relevant research of subjective well-being using the SWN, in order to

  16. Subjective well-being in schizophrenia as measured with the Subjective Well-Being under Neuroleptic Treatment scale: a review

    NARCIS (Netherlands)

    Vothknecht, Sylke; Schoevers, Robert A.; de Haan, Lieuwe

    2011-01-01

    Objective: The Subjective Well-being under Neuroleptic Treatment scale (SWN) is the most widely used self-rating scale in recent research of subjective well-being in schizophrenia. We reviewed all available publications on relevant research of subjective well-being using the SWN, in order to

  17. Quantitative evaluation of MR perfusion imaging using blood pool contrast agent in subjects without pulmonary diseases and in patients with pulmonary embolism

    Energy Technology Data Exchange (ETDEWEB)

    Hansch, Andreas; Hinneburg, Uta [University Hospital Jena, Institute of Diagnostic and Interventional Radiology II, Jena (Germany); University Hospital Jena, Institute of Diagnostic and Interventional Radiology II, Gera (Germany); Kohlmann, Peter; Laue, Hendrik [Fraunhofer MEVIS - Institute for Medical Image Computing, Bremen (Germany); Boettcher, Joachim [SRH Klinikum Gera, Institute of Diagnostic and Interventional Radiology, Gera (Germany); Malich, Ansgar [Suedharzkrankenhaus Nordhausen, Institute of Diagnostic and Interventional Radiology, Nordhausen (Germany); Wolf, Gunter [University Hospital Jena, Department of Internal Medicine III, Jena (Germany); Pfeil, Alexander [University Hospital Jena, Institute of Diagnostic and Interventional Radiology II, Jena (Germany); University Hospital Jena, Institute of Diagnostic and Interventional Radiology II, Gera (Germany); University Hospital Jena, Department of Internal Medicine III, Jena (Germany)

    2012-08-15

    To assess the feasibility of time-resolved parallel three-dimensional magnetic resonance imaging (MRI) for quantitative analysis of pulmonary perfusion using a blood pool contrast agent. Quantitative perfusion analysis was performed using novel software to assess pulmonary blood flow (PBF), pulmonary blood volume (PBV) and mean transit time (MTT) in a quantitative manner. The evaluation of lung perfusion in the normal subjects showed an increase of PBF, PBV ventrally to dorsally (gravitational direction), and the highest values at the upper lobe, with a decrease to the middle and lower lobe (isogravitational direction). MTT showed no relevant changes in either the gravitational or isogravitational directions. In comparison with normally perfused lung areas (in diseased patients), the pulmonary embolism (PE) regions showed a significantly lower mean PBF (20 {+-} 0.6 ml/100 ml/min, normal region 94 {+-} 1 ml/100 ml/min; P < 0.001), mean PBV (2 {+-} 0.1 ml/100 ml, normal region 9.8 {+-} 0.1 ml/100 ml; P < 0.001) and mean MTT (3.8 {+-} 0.1 s; normal region 6.3 {+-} 0.1; P < 0.001). Our results demonstrate the feasibility of using time-resolved dynamic contrast-enhanced MRI to determine normal range and regional variation of pulmonary perfusion and perfusion deficits in patients with PE. (orig.)

  18. Simultaneous noncontrast angiography and intraplaque hemorrhage (SNAP) imaging: Comparison with contrast-enhanced MR angiography for measuring carotid stenosis.

    Science.gov (United States)

    Shu, Hongge; Sun, Jie; Hatsukami, Thomas S; Balu, Niranjan; Hippe, Daniel S; Liu, Haining; Kohler, Ted R; Zhu, Wenzhen; Yuan, Chun

    2017-10-01

    To evaluate in a proof-of-concept study the feasibility of Simultaneous Noncontrast Angiography and intraPlaque hemorrhage (SNAP) imaging as a clinical magnetic resonance angiography (MRA) technique for measuring carotid stenosis. There is a growing interest in detecting intraplaque hemorrhage (IPH) during the clinical management of carotid disease, yet luminal stenosis has remained indispensable during clinical decision-making. SNAP imaging has been proposed as a novel IPH imaging technique that provides carotid MRA with no added scan time. Flowing blood shows negative signal on SNAP because of phase-sensitive inversion recovery. In all, 58 asymptomatic subjects with 16-79% stenosis on ultrasound were scanned at 3T by SNAP with 0.8 mm isotropic resolution and 16 cm longitudinal coverage. Two readers measured luminal stenosis of bilateral carotid arteries (n = 116) on minimum intensity projections of SNAP using the NASCET criteria. In the subset (48 arteries) with contrast-enhanced (CE) MRA available for comparison, luminal stenosis was also measured on maximum intensity projections of CE-MRA. Intraclass correlation coefficients (ICCs) with 95% confidence intervals were 0.94 (0.90-0.96) and 0.93 (0.88-0.96) for intra- and interreader agreement on stenosis measurements, respectively. Corresponding kappas for grading stenosis (0-29%, 30-69%, 70-99%, and 100%) were 0.79 (0.67-0.89) and 0.80 (0.68-0.90). Agreement between SNAP and CE-MRA was high (ICC: 0.95 [0.90-0.98]; kappa: 0.82 [0.71-0.93]). As a dedicated IPH-imaging sequence, SNAP also provided carotid stenosis measurement that showed high intra- and interreader consistency and excellent agreement with CE-MRA. Further comparisons with digital subtraction angiography and other noninvasive techniques are warranted. 2 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2017;46:1045-1052. © 2017 International Society for Magnetic Resonance in Medicine.

  19. Multispectral measurement of contrast in tissue-mimicking phantoms in near-infrared spectral range of 650 to 1600 nm.

    Science.gov (United States)

    Salo, Daniel; Zhang, Hairong; Kim, David M; Berezin, Mikhail Y

    2014-08-01

    In order to identify the optimal imaging conditions for the highest spatial contrast in biological tissue, we explored the properties of a tissue-mimicking phantom as a function of the wavelengths in a broad range of near-infrared spectra (650 to 1600 nm). Our customized multispectral hardware, which featured a scanning transmission microscope and imaging spectrographs equipped with silicon and InGaAs charge-coupled diode array detectors, allowed for direct comparison of the Michelson contrast obtained from a phantom composed of a honeycomb grid, Intralipid, and India ink. The measured contrast depended on the size of the grid, luminance, and the wavelength of measurements. We demonstrated that at low thickness of the phantom, a reasonable contrast of the objects can be achieved at any wavelength between 700 and 1400 nm and between 1500 and 1600 nm. At larger thicknesses, such contrast can be achieved mostly between 1200 and 1350 nm. These results suggest that distinguishing biological features in deep tissue and developing contrast agents for in vivo may benefit from imaging in this spectral range.

  20. Satisfaction with travel and subjective well-being: development and test of a measurement tool

    NARCIS (Netherlands)

    Ettema, D.F.; Gärling, T.; Eriksson, L.; Friman, M.; Olsson, L.E.; Fujii, S.

    2011-01-01

    Subjective well-being (SWB) that includes individuals’ cognitive and affective evaluations of life in general is proposed to be a more appropriate measure capturing the benefits individuals derive from travel improvements. We develop and testa measure of travel-related SWB, the nine item self-report

  1. Measurement of myocardial perfusion and infarction size using computer-aided diagnosis system for myocardial contrast echocardiography.

    Science.gov (United States)

    Du, Guo-Qing; Xue, Jing-Yi; Guo, Yanhui; Chen, Shuang; Du, Pei; Wu, Yan; Wang, Yu-Hang; Zong, Li-Qiu; Tian, Jia-Wei

    2015-09-01

    Proper evaluation of myocardial microvascular perfusion and assessment of infarct size is critical for clinicians. We have developed a novel computer-aided diagnosis (CAD) approach for myocardial contrast echocardiography (MCE) to measure myocardial perfusion and infarct size. Rabbits underwent 15 min of coronary occlusion followed by reperfusion (group I, n = 15) or 60 min of coronary occlusion followed by reperfusion (group II, n = 15). Myocardial contrast echocardiography was performed before and 7 d after ischemia/reperfusion, and images were analyzed with the CAD system on the basis of eliminating particle swarm optimization clustering analysis. The myocardium was quickly and accurately detected using contrast-enhanced images, myocardial perfusion was quantitatively calibrated and a color-coded map calibrated by contrast intensity and automatically produced by the CAD system was used to outline the infarction region. Calibrated contrast intensity was significantly lower in infarct regions than in non-infarct regions, allowing differentiation of abnormal and normal myocardial perfusion. Receiver operating characteristic curve analysis documented that -54-pixel contrast intensity was an optimal cutoff point for the identification of infarcted myocardium with a sensitivity of 95.45% and specificity of 87.50%. Infarct sizes obtained using myocardial perfusion defect analysis of original contrast images and the contrast intensity-based color-coded map in computerized images were compared with infarct sizes measured using triphenyltetrazolium chloride staining. Use of the proposed CAD approach provided observers with more information. The infarct sizes obtained with myocardial perfusion defect analysis, the contrast intensity-based color-coded map and triphenyltetrazolium chloride staining were 23.72 ± 8.41%, 21.77 ± 7.8% and 18.21 ± 4.40% (% left ventricle) respectively (p > 0.05), indicating that computerized myocardial contrast echocardiography can

  2. Measurements and simulations analysing the noise behaviour of grating-based X-ray phase-contrast imaging

    Energy Technology Data Exchange (ETDEWEB)

    Weber, T., E-mail: thomas.weber@physik.uni-erlangen.de [University of Erlangen-Nuremberg, ECAP - Erlangen Center for Astroparticle Physics, Erwin-Rommel-Str. 1, 91058 Erlangen (Germany); Bartl, P.; Durst, J. [University of Erlangen-Nuremberg, ECAP - Erlangen Center for Astroparticle Physics, Erwin-Rommel-Str. 1, 91058 Erlangen (Germany); Haas, W. [University of Erlangen-Nuremberg, ECAP - Erlangen Center for Astroparticle Physics, Erwin-Rommel-Str. 1, 91058 Erlangen (Germany); University of Erlangen-Nuremberg, Pattern Recognition Lab, Martensstr. 3, 91058 Erlangen (Germany); Michel, T.; Ritter, A.; Anton, G. [University of Erlangen-Nuremberg, ECAP - Erlangen Center for Astroparticle Physics, Erwin-Rommel-Str. 1, 91058 Erlangen (Germany)

    2011-08-21

    In the last decades, phase-contrast imaging using a Talbot-Lau grating interferometer is possible even with a low-brilliance X-ray source. With the potential of increasing the soft-tissue contrast, this method is on its way into medical imaging. For this purpose, the knowledge of the underlying physics of this technique is necessary. With this paper, we would like to contribute to the understanding of grating-based phase-contrast imaging by presenting results on measurements and simulations regarding the noise behaviour of the differential phases. These measurements were done using a microfocus X-ray tube with a hybrid, photon-counting, semiconductor Medipix2 detector. The additional simulations were performed by our in-house developed phase-contrast simulation tool 'SPHINX', combining both wave and particle contributions of the simulated photons. The results obtained by both of these methods show the same behaviour. Increasing the number of photons leads to a linear decrease of the standard deviation of the phase. The number of used phase steps has no influence on the standard deviation, if the total number of photons is held constant. Furthermore, the probability density function (pdf) of the reconstructed differential phases was analysed. It turned out that the so-called von Mises distribution is the physically correct pdf, which was also confirmed by measurements. This information advances the understanding of grating-based phase-contrast imaging and can be used to improve image quality.

  3. Validity and reliability of subjective wellbeing indicators in sociological research: The measurement of life satisfaction

    Directory of Open Access Journals (Sweden)

    Mentus Vladimir

    2017-01-01

    Full Text Available The subject of this paper is the level of accuracy i.e. validity and reliability of subjective well-being indicators in sociological research, in case of life satisfaction. First, the relationship between subjective and objective indicators of well-being is presented. Second, the concept of life satisfaction is defined, and the findings of research related to the validity (convergent, discriminant, and predictive and reliability (test-retest, and internal consistency of life satisfaction measures are presented. Third, these findings were reassessed using data originating from large international surveys, which have not been used for this purpose yet. The results in this paper generally contribute to, in quite a large extent existing agreement within the scientific literature about the satisfactory level of validity and reliability of life satisfaction measures i.e. subjective indicators of well-being.

  4. Mood Influences the Concordance of Subjective and Objective Measures of Sleep Duration in Older Adults

    Directory of Open Access Journals (Sweden)

    Marion Baillet

    2016-07-01

    Full Text Available Objective/Background: Sleep plays a central role in maintaining health and cognition. In most epidemiologic studies, sleep is evaluated by self-report questionnaires but several reports suggest that these evaluations might be less accurate than objective measures such as polysomnography or actigraphy. Determinants of the discrepancy between objective and subjective measures remain to be investigated. The aim of this pilot-study was to examine the role of mood states in determining the discrepancy observed between objective and subjective measures of sleep duration in older adults.Patients/Methods: Objective sleep quantity and quality were recorded by actigraphy in a sample of 45 elderly subjects over at least three consecutive nights. Subjective sleep duration and supplementary data, such as mood status and memory, were evaluated using Ecological Momentary Assessment (EMA.Results: A significant discrepancy was observed between EMA and actigraphic measures of sleep duration (p<0.001. The magnitude of this difference was explained by the patient’s mood status (p=0.020. No association was found between the magnitude of this discrepancy and age, sex, sleep quality or memory performance.Conclusion: The discrepancy classically observed between objective and subjective measures of sleep duration can be explained by mood status at the time of awakening. These results have potential implications for epidemiologic and clinical studies examining sleep as a risk factor for morbidity or mortality.

  5. Mood Influences the Concordance of Subjective and Objective Measures of Sleep Duration in Older Adults.

    Science.gov (United States)

    Baillet, Marion; Cosin, Charlotte; Schweitzer, Pierre; Pérès, Karine; Catheline, Gwenaëlle; Swendsen, Joel; Mayo, Willy

    2016-01-01

    Sleep plays a central role in maintaining health and cognition. In most epidemiologic studies, sleep is evaluated by self-report questionnaires but several reports suggest that these evaluations might be less accurate than objective measures such as polysomnography or actigraphy. Determinants of the discrepancy between objective and subjective measures remain to be investigated. The aim of this pilot-study was to examine the role of mood states in determining the discrepancy observed between objective and subjective measures of sleep duration in older adults. Objective sleep quantity and quality were recorded by actigraphy in a sample of 45 elderly subjects over at least three consecutive nights. Subjective sleep duration and supplementary data, such as mood status and memory, were evaluated using ecological momentary assessment (EMA). A significant discrepancy was observed between EMA and actigraphic measures of sleep duration (p sleep quality or memory performance. The discrepancy classically observed between objective and subjective measures of sleep duration can be explained by mood status at the time of awakening. These results have potential implications for epidemiologic and clinical studies examining sleep as a risk factor for morbidity or mortality.

  6. Subjective measures of hearing aid benefit in the NIDCD/VA Clinical Trial.

    Science.gov (United States)

    Haskell, George B; Noffsinger, Douglas; Larson, Vernon D; Williams, David W; Dobie, Robert A; Rogers, Janette L

    2002-08-01

    Subjective measures of performance were assessed on three different hearing aid circuits as part of a large clinical trial. These measurements included the Profile of Hearing Aid Performance and a subjective ranking of individual preference. A multi-center, double-masked clinical trial of hearing aids was conducted at eight VA Medical Centers. Three hearing aid circuits, a linear peak-clipper, a linear compression limiter and a wide dynamic range compressor, were investigated. The experimental design was a three-period, three-treatment crossover design. Subjects (N = 360) were stratified by site and randomized to one of six sequences for the hearing aid circuits. All fittings were binaural and involved a 3-mo trial with each of the three circuits. All subjective measures were administered for unaided and aided conditions at the end of each trial period. While all of the circuits resulted in improved scores on the aided versus the unaided PHAP, there were few conditions in which one circuit outperformed the others. An exception was the aversiveness of sound subscale where the peak clipper frequently scored worse than either the compression limiter or the wide dynamic range compressor. In the subjective ranking scale the compression limiter received more first place rankings than the other two circuits, especially for one subgroup of patients with moderate flat hearing loss. All circuits were perceived as beneficial by these subjects in most situations. The peak clipper scored worse on aversiveness of sound than did the other two circuits for most subjects, while the compression limiter seemed to have a slight advantage in subjective rankings. Most subjects perceived considerable aided benefit in situations involving background noise and reverberation, situations where hearing aid benefit is often questioned.

  7. Retinal nerve fiber layer measurements by scanning laser polarimetry with enhanced corneal compensation in healthy subjects.

    Science.gov (United States)

    Rao, Harsha L; Venkatesh, Chirravuri R; Vidyasagar, Kelli; Yadav, Ravi K; Addepalli, Uday K; Jude, Aarthi; Senthil, Sirisha; Garudadri, Chandra S

    2014-12-01

    To evaluate the (i) effects of biological (age and axial length) and instrument-related [typical scan score (TSS) and corneal birefringence] parameters on the retinal nerve fiber layer (RNFL) measurements and (ii) repeatability of RNFL measurements with the enhanced corneal compensation (ECC) protocol of scanning laser polarimetry (SLP) in healthy subjects. In a cross-sectional study, 140 eyes of 73 healthy subjects underwent RNFL imaging with the ECC protocol of SLP. Linear mixed modeling methods were used to evaluate the effects of age, axial length, TSS, and corneal birefringence on RNFL measurements. One randomly selected eye of 48 subjects from the cohort underwent 3 serial scans during the same session to determine the repeatability. Age significantly influenced all RNFL measurements. RNFL measurements decreased by 1 µm for every decade increase in age. TSS affected the overall average RNFL measurement (β=-0.62, P=0.003), whereas residual anterior segment retardance affected the superior quadrant measurement (β=1.14, P=0.01). Axial length and corneal birefringence measurements did not influence RNFL measurements. Repeatability, as assessed by the coefficient of variation, ranged between 1.7% for the overall average RNFL measurement and 11.4% for th nerve fiber indicator. Age significantly affected all RNFL measurements with the ECC protocol of SLP, whereas TSS and residual anterior segment retardance affected the overall average and the superior average RNFL measurements, respectively. Axial length and corneal birefringence measurements did not influence any RNFL measurements. RNFL measurements had good intrasession repeatability. These results are important while evaluating the change in structural measurements over time in glaucoma patients.

  8. Simultaneous blood flow and blood oxygenation measurements using a combination of diffuse speckle contrast analysis and near-infrared spectroscopy

    Science.gov (United States)

    Seong, Myeongsu; Phillips, Zephaniah; Mai, Phuong Minh; Yeo, Chaebeom; Song, Cheol; Lee, Kijoon; Kim, Jae Gwan

    2016-02-01

    A combined diffuse speckle contrast analysis (DSCA)-near-infrared spectroscopy (NIRS) system is proposed to simultaneously measure qualitative blood flow and blood oxygenation changes in human tissue. The system employs an optical switch to alternate two laser sources at two different wavelengths and a CCD camera to capture the speckle image. Therefore, an optical density can be measured from two wavelengths for NIRS measurements and a speckle contrast can be calculated for DSCA measurements. In order to validate the system, a flow phantom test and an arm occlusion protocol for arterial and venous occlusion were performed. Shorter exposure times (oxyhemoglobin (OHb) and deoxyhemoglobin (RHb) during arterial occlusion (max RHb=0.0085±0.0024 mM/DPF, min OHb=-0.0057±0.0044 mM/DPF). The sensitivity of the system makes it a suitable modality to observe qualitative hemodynamic trends during induced physiological changes.

  9. Objective and subjective measures of neighborhood environment (NE): relationships with transportation physical activity among older persons.

    Science.gov (United States)

    Nyunt, Ma Shwe Zin; Shuvo, Faysal Kabir; Eng, Jia Yen; Yap, Keng Bee; Scherer, Samuel; Hee, Li Min; Chan, Siew Pang; Ng, Tze Pin

    2015-09-15

    This study examined the associations of subjective and objective measures of the neighbourhood environment with the transportation physical activity of community-dwelling older persons in Singapore. A modified version of the Neighborhood Environment Walkability Scale (NEWS) and Geographical Information System (GIS) measures of the built environment characteristics were related to the frequency of walking for transportation purpose in a study sample of older persons living in high-density apartment blocks within a public housing estate in Singapore. Relevant measured variables to assess the complex relationships among built environment measures and transportation physical activity were examined using structural equation modelling and multiple regression analyses. The subjective measures of residential density, street connectivity, land use mix diversity and aesthetic environment and the objective GIS measure of Accessibility Index have positively significant independent associations with transportation physical activity, after adjusting for demographics, socio-economic and health status. Subjective and objective measures are non-overlapping measures complementing each other in providing information on built environment characteristics. For elderly living in a high-density urban neighborhood, well connected street, diversity of land use mix, close proximity to amenities and facilities, and aesthetic environment were associated with higher frequency of walking for transportation purposes.

  10. Normal breast parenchyma: contrast enhancement kinetics at dynamic MR mammography--influence of anthropometric measures and menopausal status.

    Science.gov (United States)

    Hegenscheid, Katrin; Schmidt, Carsten O; Seipel, Rebecca; Laqua, René; Ohlinger, Ralf; Kühn, Jens-Peter; Hosten, Norbert; Puls, Ralf

    2013-01-01

    To study T1 baseline signal intensity (SI) and contrast material enhancement kinetics of normal breast parenchyma by using dynamic contrast-enhanced (DCE) magnetic resonance (MR) mammography and to determine the influence of anthropometric measures and menopausal status on the variability of these features. Institutional review board approval and written informed consent were obtained. Between June 2008 and September 2011, 345 women (age range, 26-81 years; mean age, 51.3 years ± 11.6 [standard deviation]) underwent DCE MR mammography, with T1-weighted three-dimensional MR images (repetition time msec/echo time msec, 8.86/4.51; flip angle, 25°) acquired with a 1.5-T whole-body MR unit before and 1, 2, 3, 4, and 5 minutes after a gadobutrol bolus injection of 0.1 mmol per kilogram of body weight. Regions of interest were traced manually, and T1 SI of parenchyma was recorded. The influence of different predictors of T1 baseline SI and contrast enhancement was studied by using random-effects models. T1 baseline SI varied considerably between women, with a mean of 167.7 ± 49.2 (71.4-424.7 [range]) and 175.9 ± 48.9 (51.8-458.3) in the right and the left breast, respectively (P contrast material delivery, relative percentage of enhancement was 8.1%, 13.8%, 18.2%, 22.1%, and 24.6% at 1, 2, 3, 4, and 5 minutes, respectively, but varied considerably between women. Contrast enhancement was 9.3% in the lowest quintile and 47.4% in the highest. Contrast enhancement increased with body weight (P contrast enhancement slope. Anthropometric measures and menopausal status contribute to a large variability in contrast enhancement of normal breast parenchyma. This might influence the interpretation of contrast enhancement kinetics of breast lesions and current strategies for determining contrast medium dose for breast MR imaging. RSNA, 2012

  11. Reproducibility of the measurements of knee joint proprioception in patients with osteoarthritis of the knee and healthy subject

    NARCIS (Netherlands)

    Hurkmans, E.; van der Esch, M.; Ostelo, R.W.J.G.; Knol, D.L.; Dekker, J; Steultjens, M

    2007-01-01

    Objective. To estimate the inter- and intrarater reliability and agreement of instrumented knee joint proprioception measurement in subjects with knee osteoarthritis (OA) and healthy subjects; to assess the effect of variations in the measurement procedure on agreement parameters. Methods.

  12. Measuring Welfare beyond GDP : 'Objective' and 'Subjective' Indicators in Sweden, 1968-2015

    Directory of Open Access Journals (Sweden)

    Christopher Kullenberg

    2017-10-01

    Full Text Available This article analyses a series of negotiations on how to measure welfare and quality of life in Sweden beyond economic indicators. It departs from a 2015 Government Official Report that advanced a strong recommendation to measure only 'objective indicators' of quality of life, rather than relying on what is referred to as 'subjective indicators' such as life satisfaction and happiness. The assertion of strictly 'objective' indicators falls back on a sociological perspective developed in the 1970s, which conceived of welfare as being measurable as 'levels of living', a framework that came to be called 'the Scandinavian model of welfare research'. However, in the mid-2000s, objective indicators were challenged scientifically by the emerging field of happiness studies, which also found political advocates in Sweden who argued that subjective indicators should become an integral part of measuring welfare. This tension between 'subjective' and 'objective' measurements resulted in a controversy between several actors about what should count as a valuable measurement of welfare. As a consequence, we argue that the creation of such value meters is closely intertwined with how welfare is defined, and by what measures welfare should be carried through.

  13. Contrasting effect of prepulse signals on performance of Toxoplasma-infected and Toxoplasma-free subjects in an acoustic reaction times test.

    Directory of Open Access Journals (Sweden)

    Lenka Příplatová

    Full Text Available About 30% of people on Earth have latent toxoplasmosis. Infected subjects do not express any clinical symptoms, however, they carry dormant stages of parasite Toxoplasma for the rest of their life. This form of toxoplasmosis is mostly considered harmless, however, recent studies showed its specific effects on physiology, behaviour and its associations with various diseases, including psychiatric disorders such as schizophrenia. Individuals who suffer from schizophrenia have about 2.7 times higher prevalence of Toxoplasma-seropositivity than controls, which suggests that some traits characteristic of schizophrenic patients, including the sex difference in schizophrenia onset, decrease of grey matter density in specific brain areas and modification of prepulse inhibition of startle reaction could in fact be caused by toxoplasmosis for those patients who are Toxoplasma-seropositive.We measured the effect of prepulse inhibition/facilitation of the startle reaction on reaction times. The students, 170 women and 66 men, were asked to react as quickly as possible to a startling acoustic signal by pressing a computer mouse button. Some of the startling signals were without the prepulse, some were 20 msec. preceded by a short (20 msec. prepulse signal of lower intensity. Toxoplasma-seropositive subjects had longer reaction times than the controls. Acoustic prepulse shorted the reaction times in all subjects. This effect of prepulse on reaction times was stronger in male subjects and increased with the duration of infection, suggesting that it represented a cumulative effect of latent toxoplasmosis, rather than a fading out after effect of past acute toxoplasmosis.Different sensitivity of Toxoplasma-seropositive and Toxoplasma-seronegative subjects on effect of prepulses on reaction times (the toxoplasmosis-prepulse interaction suggested, but of course did not prove, that the alternations of prepulse inhibition of startle reaction observed in

  14. Mood and objective and subjective measures of sleep during late pregnancy and the postpartum period.

    Science.gov (United States)

    Coo, Soledad; Milgrom, Jeannette; Trinder, John

    2014-01-01

    This study examined the association between measures of objective sleep (OS) and subjective sleep (SS) to postpartum mood in healthy women from the third trimester of pregnancy to 10 to 12 weeks postpartum. Twenty-nine pregnant women completed self-report measures of mood and SS, and wore actigraphs for 7 continuous days during the third trimester (Time 1), within 15 days (Time 2), and 10 to 12 weeks postpartum (Time 3). The subjective perception of marked daytime dysfunction was associated with low mood during Time 1 and Time 3. Poor nighttime SS was related to low mood only at Time 2, whereas poor nighttime OS influenced stress during the same assessment time. These data indicate a stronger association between postpartum mood and the subjective perception of sleep than with OS quality and duration in healthy, non-depressed women, and highlight the awareness of poor daytime functioning as a significant contributor to new mothers' emotional wellbeing.

  15. Dynamic contrast-enhanced quantitative perfusion measurement of the brain using T-1-weighted MRI at 3T

    DEFF Research Database (Denmark)

    Larsson, H.B.W.; Hansen, A.E.; Berg, H.K.

    2008-01-01

    inside the infarct core was, 9 mL/100g/min in one of the stroke patients. The other stroke patient had postischemic hyperperfusion and CBF was 140 mL/100g/min. Conclusion: Absolute values of brain perfusion can be obtained using dynamic contrast-enhanced MRI. These values correspond,to expected values......Purpose: To develop a method for the measurement of brain perfusion based on dynamic contrast-enhanced T-1-weighted MR imaging. Materials and Methods: Dynamic imaging of the first pass of a bolus of a paramagnetic contrast agent was performed using a 3T whole-body magnet and a T-1-weighted fast...

  16. Objectively and subjectively measured physical activity: associations with cognition and academic achievement in adolescents

    NARCIS (Netherlands)

    Van Dijk, Martin; De Groot, Renate; Van Acker, Frederik; Savelberg, Hans; Kirschner, Paul A.

    2013-01-01

    Van Dijk, M. L., De Groot, R. H. M., Van Acker, F., Savelberg, H. C. M., & Kirschner, P. A. (2013, 26 February). Objectively and subjectively measured physical activity: associations with cognition and academic achievement in adolescents. Presentation at the CELSTEC plenary, Heerlen, The

  17. "Chips with Everything": A Laboratory Exercise for Comparing Subjective and Objective Measurements of Potato Chips

    Science.gov (United States)

    Davies, Cathy

    2005-01-01

    The following laboratory exercise was designed to aid student understanding of the differences between subjective and objective measurements. Students assess the color and texture of different varieties of potato chip (crisps) by means of an intensity rating scale and a rank test and objectively with a colorimeter and texture analyzer. For data…

  18. Measuring Quality of Life in Stroke Subjects Receiving an Implanted Neural Prosthesis for Drop Foot

    NARCIS (Netherlands)

    Kottink, Anke I.; IJzerman, Maarten Joost; Hermens, Hermanus J.; Groothuis-Oudshoorn, Catharina Gerarda Maria; Kottink, A.I.R.

    2010-01-01

    The aim was to determine if the treatment of a drop foot by means of an implantable two-channel peroneal nerve stimulator improves health-related quality of life (HRQoL). All subjects were measured at baseline and after a follow-up period of 12 and 26 weeks. Twenty-nine stroke survivors with chronic

  19. Objectively versus subjectively measured physical activity: associations with cognition and academic achievement in adolescents

    NARCIS (Netherlands)

    Van Dijk, Martin; De Groot, Renate; Savelberg, Hans; Van Acker, Frederik; Kirschner, Paul A.

    2013-01-01

    Van Dijk, M. L., De Groot, R. H. M., Savelberg, H. C. M., Van Acker, F. H. M., & Kirschner, P. A. (2013, 25 May). Objectively versus subjectively measured physical activity: associations with cognition and academic achievement in adolescents. Poster presentation at the ISBNPA conference 2013, Ghent,

  20. A Short Introduction to Subjective Well-being: Measurement, Correlates and Policy Uses

    NARCIS (Netherlands)

    Hoorn, A.A.J. van

    2008-01-01

    Since the emergence of the field over five decades ago, the subjective well-being (SWB; e.g. self-reported happiness or life satisfaction) literature has progressed rapidly. This overview discusses the state of the art in the measurement of SWB, the understanding of the factors determining SWB,

  1. Measure of microscopy mineral image clarity constructed using the sequentially combined toggle and top-hat based contrast operator.

    Science.gov (United States)

    Bai, Xiangzhi

    2013-08-01

    Correctly and effectively quantifying the clarity of microscopy mineral image is important and useful to produce clear image for mineral analysis. To well quantify the clarity of mineral image, an effective measure constructed using the sequentially combined toggle and top-hat based contrast operator is proposed in this article. First, the sequentially combined toggle and top-hat based contrast operator is used to extract the effective features which represent the clarity of mineral image. Second, the multiscale clarity features corresponding to each scale are extracted. Finally, after combining the multiscale clarity features in one feature image, the mean value of the feature image is constructed as the measure of mineral image clarity. Because the sequentially combined toggle and top-hat based contrast operator could effectively extract the clarity features, the clarity features are directly used as the measure of image clarity. Therefore, the proposed measure is effective and reasonable. The experimental results on different types of microscopy mineral images verified the effective performance of the proposed measure. Copyright © 2013 Wiley Periodicals, Inc.

  2. Comparison of verbal and pictorial measures of hunger during fasting in normal weight and obese subjects.

    Science.gov (United States)

    Lowe, M R; Friedman, M I; Mattes, R; Kopyt, D; Gayda, C

    2000-11-01

    Friedman, Ulrich, and Mattes described a new pictorial instrument for assessing hunger wherein respondents outline areas on a drawing of a human figure to depict the location of their hunger sensations. The present study compared normal weight and obese individuals on the pictorial measure and on more traditional verbal hunger measures during a 22-hour fast. The pictorial measure, along with 13 verbal items assessing hunger and hunger-related symptoms, was administered to 29 normal weight college students and 46 overweight clinic patients four times during a 22-hour fast. Factor analyses of verbal hunger items produced Hunger, Somatic Symptoms, and Stomach Symptoms factors. The pictorial measure was divided into peripheral (arms, legs, head) and central (trunk) body areas. The increases in hunger during the fast were greater when measured using the pictorial as opposed to the verbal instrument. Correlations between and within the three verbal hunger measures and two pictorial measures were generally few in number and modest in size. The overall pattern of correlations suggested that the verbally based hunger measures more adequately reflected the experience of hunger in normal weight than in obese individuals. A significant interaction between weight status and assessment period was found for the pictorial measure, indicating that normal weight subjects experienced more bodily hunger than overweight subjects initially but experienced less hunger than obese subjects after a prolonged period of food deprivation. Although more testing is needed, these results suggest that the pictorial hunger assessment provides information about the experience of hunger that could complement information provided by traditional verbally based hunger measures.

  3. Objective measurement of daytime napping, cognitive dysfunction and subjective sleepiness in Parkinson's disease.

    Directory of Open Access Journals (Sweden)

    Samuel J Bolitho

    Full Text Available INTRODUCTION: Sleep-wake disturbances and concomitant cognitive dysfunction in Parkinson's disease (PD contribute significantly to morbidity in patients and their carers. Subjectively reported daytime sleep disturbance is observed in over half of all patients with PD and has been linked to executive cognitive dysfunction. The current study used daytime actigraphy, a novel objective measure of napping and related this to neuropsychological performance in a sample of PD patients and healthy, age and gender-matched controls. Furthermore this study aimed to identify patients with PD who may benefit from pharmacologic and behavioural intervention to improve these symptoms. METHODS: Eighty-five PD patients and 21 healthy, age-matched controls completed 14 days of wrist actigraphy within two weeks of neuropsychological testing. Objective napping measures were derived from actigraphy using a standardised protocol and subjective daytime sleepiness was recorded by the previously validated Epworth Sleepiness Scale. RESULTS: Patients with PD had a 225% increase in the mean nap time per day (minutes as recorded by actigraphy compared to age matched controls (39.2 ± 35.2 vs. 11.5 ± 11.0 minutes respectively, p < 0.001. Significantly, differences in napping duration between patients, as recorded by actigraphy were not distinguished by their ratings on the subjective measurement of excessive daytime sleepiness. Finally, those patients with excessive daytime napping showed greater cognitive deficits in the domains of attention, semantic verbal fluency and processing speed. CONCLUSION: This study confirms increased levels of napping in PD, a finding that is concordant with subjective reports. However, subjective self-report measures of excessive daytime sleepiness do not robustly identify excessive napping in PD. Fronto-subcortical cognitive dysfunction was observed in those patients who napped excessively. Furthermore, this study suggests that daytime

  4. Objective Measurement of Daytime Napping, Cognitive Dysfunction and Subjective Sleepiness in Parkinson’s Disease

    Science.gov (United States)

    Bolitho, Samuel J.; Naismith, Sharon L.; Salahuddin, Pierre; Terpening, Zoe; Grunstein, Ron R.; Lewis, Simon J. G.

    2013-01-01

    Introduction Sleep-wake disturbances and concomitant cognitive dysfunction in Parkinson’s disease (PD) contribute significantly to morbidity in patients and their carers. Subjectively reported daytime sleep disturbance is observed in over half of all patients with PD and has been linked to executive cognitive dysfunction. The current study used daytime actigraphy, a novel objective measure of napping and related this to neuropsychological performance in a sample of PD patients and healthy, age and gender-matched controls. Furthermore this study aimed to identify patients with PD who may benefit from pharmacologic and behavioural intervention to improve these symptoms. Methods Eighty-five PD patients and 21 healthy, age-matched controls completed 14 days of wrist actigraphy within two weeks of neuropsychological testing. Objective napping measures were derived from actigraphy using a standardised protocol and subjective daytime sleepiness was recorded by the previously validated Epworth Sleepiness Scale. Results Patients with PD had a 225% increase in the mean nap time per day (minutes) as recorded by actigraphy compared to age matched controls (39.2 ± 35.2 vs. 11.5 ± 11.0 minutes respectively, p napping duration between patients, as recorded by actigraphy were not distinguished by their ratings on the subjective measurement of excessive daytime sleepiness. Finally, those patients with excessive daytime napping showed greater cognitive deficits in the domains of attention, semantic verbal fluency and processing speed. Conclusion This study confirms increased levels of napping in PD, a finding that is concordant with subjective reports. However, subjective self-report measures of excessive daytime sleepiness do not robustly identify excessive napping in PD. Fronto-subcortical cognitive dysfunction was observed in those patients who napped excessively. Furthermore, this study suggests that daytime actigraphy, a non-invasive and inexpensive objective measure of

  5. Objective measurement of daytime napping, cognitive dysfunction and subjective sleepiness in Parkinson's disease.

    Science.gov (United States)

    Bolitho, Samuel J; Naismith, Sharon L; Salahuddin, Pierre; Terpening, Zoe; Grunstein, Ron R; Lewis, Simon J G

    2013-01-01

    Sleep-wake disturbances and concomitant cognitive dysfunction in Parkinson's disease (PD) contribute significantly to morbidity in patients and their carers. Subjectively reported daytime sleep disturbance is observed in over half of all patients with PD and has been linked to executive cognitive dysfunction. The current study used daytime actigraphy, a novel objective measure of napping and related this to neuropsychological performance in a sample of PD patients and healthy, age and gender-matched controls. Furthermore this study aimed to identify patients with PD who may benefit from pharmacologic and behavioural intervention to improve these symptoms. Eighty-five PD patients and 21 healthy, age-matched controls completed 14 days of wrist actigraphy within two weeks of neuropsychological testing. Objective napping measures were derived from actigraphy using a standardised protocol and subjective daytime sleepiness was recorded by the previously validated Epworth Sleepiness Scale. Patients with PD had a 225% increase in the mean nap time per day (minutes) as recorded by actigraphy compared to age matched controls (39.2 ± 35.2 vs. 11.5 ± 11.0 minutes respectively, p napping duration between patients, as recorded by actigraphy were not distinguished by their ratings on the subjective measurement of excessive daytime sleepiness. Finally, those patients with excessive daytime napping showed greater cognitive deficits in the domains of attention, semantic verbal fluency and processing speed. This study confirms increased levels of napping in PD, a finding that is concordant with subjective reports. However, subjective self-report measures of excessive daytime sleepiness do not robustly identify excessive napping in PD. Fronto-subcortical cognitive dysfunction was observed in those patients who napped excessively. Furthermore, this study suggests that daytime actigraphy, a non-invasive and inexpensive objective measure of daytime sleep, can identify patients with PD

  6. Local effects in the respiratory tract: relevance of subjectively measured irritation for setting occupational exposure limits.

    Science.gov (United States)

    Arts, Josje H E; de Heer, Cees; Woutersen, Ruud A

    2006-04-01

    Chemosensory effects of stimulation by a chemical can either be irritating (trigeminal stimulation) or odorous (olfactory stimulation) or both. For odorous irritants, a clear-cut distinction between odour and irritation is difficult to make. The differences in the lowest concentration found to be irritating to the respiratory tract in humans when compared to experimental animals has brought much debate in the process of setting occupational exposure limits (OELs) for such chemicals. In this paper it will be discussed as to how far subjectively measured sensory irritation threshold levels can be used to establish OELs. Data on respiratory irritation of four odorous irritants were retrieved from public literature and discussed, viz. acetone, formaldehyde, furfural and sulphur dioxide. Objective measures of irritation yielded results that differed from subjective evaluations. Important factors modulating the reported levels of irritation and health symptoms include the perception of odour intensity, exposure history and the individual's bias to report irritation on the basis of his/her prejudice or knowledge of the compound. Subjective measures alone are less appropriate for establishing sensory irritation thresholds of odorous irritants and are, therefore, less suitable to establish OELs without supporting evidence. Objectively measured irritation in humans, the Alarie assay (an experimental animal test assessing the concentration that results in a 50% reduction of the breathing frequency) and repeated exposure studies in animals may be of help to study objective irritation. If subjective measurements are used to study sensory irritation, the study design should at least include: measurement of both incidence and severity determined at several concentrations, an appropriate (0 ppm) control condition, preferably a non-irritant odorant control exposure, validated questionnaires and correct concentration measurements.

  7. Multichannel SQUID system for measurement of spinal cord evoked magnetic field for supine subjects

    Energy Technology Data Exchange (ETDEWEB)

    Adachi, Y; Kawai, J; Miyamoto, M; Uehara, G; Ogata, H [Applied Electronics Laboratory, Kanazawa Institute of Technology, 3 Amaike, Kanazawa, Ishikawa, 920-1331 (Japan); Kawabata, S [Section of Orthopaedic and Spinal Surgery, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8519 (Japan)

    2008-02-01

    A SQUID biomagnetometer system for cervical spinal cord evoked field (SCEF) was developed to investigate a non-invasive diagnosis of function of the spinal cord. The measurement system was characterized by a uniquely shaped cryostat designed for supine subjects. The cryostat has a vertical cylindrical main body whose dimensions are 500 mm in diameter and 940 mm in height and a horizontal protrusion from the side surface with 390 mm of length. The sensor array of 35 LTS-SQUID vector gradiometers directed vertically upward is installed in the end of the protruded part. Subjects lie on a bed in supine position with the head running off the edge of the bed and the back of the neck supported on the upper surface of the protruded part of the cryostat standing beside the bed. This structure readily enables the sensor array to approach close to the neck of the supine subject. The subjects can keep their posture stable during the measurement. We demonstrated the cervical SCEF was successfully detected from a healthy subject who was given electric stimulation to the median nerve at the wrist. The intensity of the evoked magnetic field was 40-70 fT in amplitude. The neural signal propagating along the spinal cord was magnetically observed from the investigation of the transition of the magnetic field distribution.

  8. Measurement of contrast of phantom and in vivo subsurface blood vessels using two near-infrared imaging systems

    Science.gov (United States)

    Hebden, Jeremy C.; Alkhaja, Aysha; Mahe, Laure; Powell, S.; Everdell, N. L.

    2015-03-01

    A quantitative comparison has been performed between two commercial near-infrared (NIR) vein-viewing systems which are designed to supplement the clinician's traditional skills in locating veins by means of visualization and palpation. The AccuVein AV300 and Novarix IV-eye real-time imaging systems employ very different imaging geometries; the former generates an image from reflected NIR light produced by a beam scanned across the surface, while the latter illuminates the viewed region at four points on the periphery and records the resulting distribution of diffusely transmitted light. The comparison involved measuring the contrast produced by absorbing rods (simulated blood vessels) in a cylindrical phantom with tissue-like optical properties, and the contrast of superficial blood vessels in the arms of healthy volunteers. The locations and sizes of the blood vessels were independently verified using a clinical ultrasound imaging system. The phantom measurements suggested that the AV300 displays the most superficial vessels with greater contrast, but the IV-eye is able to detect vessels when they are at a depth up to 2 mm greater than the limit observed for the AV300. The results for thirty healthy volunteers also indicated that the AV300 typically displays vessels with higher overall contrast, but the effectiveness of the IV-eye at visualizing deeper vessels was even more pronounced, with a maximum depth several millimeters greater than that achieved by the AV300, and more than ten times as many vessels observed at depths below 4 mm.

  9. Developments Toward Diagnostic Breast Cancer Imaging Using Near-Infrared Optical Measurements and Fluorescent Contrast Agents1

    Directory of Open Access Journals (Sweden)

    Daniel J. Hawrysz

    2000-09-01

    Full Text Available The use of near-infrared (NIR light to interrogate deep tissues has enormous potential for molecular-based imaging when coupled with NIR excitable dyes. More than a decade has now passed since the initial proposals for NIR optical tomography for breast cancer screening using time-dependent measurements of light propagation in the breast. Much accomplishment in the development of optical mammography has been demonstrated, most recently in the application of time-domain, frequency-domain, and continuous-wave measurements that depend on endogenous contrast owing to angiogenesis and increased hemoglobin absorbance for contrast. Although exciting and promising, the necessity of angiogenesis-mediated absorption contrast for diagnostic optical mammography minimizes the potential for using NIR techniques to assess sentinel lymph node staging, metastatic spread, and multifocality of breast disease, among other applications. In this review, we summarize the progress made in the development of optical mammography, and focus on the emerging work underway in the use of diagnostic contrast agents for the molecular-based, diagnostic imaging of breast.

  10. Comparison of Occlusion Effect in Normal Hearing Subjects via Real Ear Measurement and Audiometric Bing Test

    Directory of Open Access Journals (Sweden)

    Meymaneh Jafari

    2009-12-01

    Full Text Available Background and Aim: One of the most common complaints, particularly among patients with normal or near normal low-frequency hearing, is that their voice sounds "hollow". This is associated with "Occlusion effect". The aim of this study was to comparison of occlusion effect in normal hearing subjects via Real Ear Measurement and Audiometric Bing test. Materials and Method: Twenty volunteers with normal hearing (10 male, 10 female, with ages ranging from 18 – 24 years were enrolled in this study. First, audiometric Bing test was performed in frequencies of 250, 500, 750 and 1000 Hz. Then in real ear measurement, subjects were instructed to vocalize /â/ and /i/ for 5 seconds. Probe microphone was recorded the sound pressure in the ear canals. The degrees of occlusion effect unit were obtained for further analysis.Results: The means of occlusion effect were present in all subjects. There was no correlation between the results of audiometric Bing test and real-ear measurement. No significant difference was obtained between genders and monaural or binaural occlusion in real-ear measurement. But in audiometric Bing test, the difference between monaural or binaural occlusion was significant(p<0.05.Conclusion: The peak of occlusion effect varies significantly among hearing aid users, so the hearing aid must be tuned. Probe- microphone measures will assist in determination how much gain is enough, and where frequency- specific adjustments are needed.

  11. Anxiety and cerebral blood flow during behavioral challenge. Dissociation of central from peripheral and subjective measures

    Energy Technology Data Exchange (ETDEWEB)

    Zohar, J.; Insel, T.R.; Berman, K.F.; Foa, E.B.; Hill, J.L.; Weinberger, D.R.

    1989-06-01

    To investigate the relationship between anxiety and regional cerebral blood flow, we administered behavioral challenges to 10 patients with obsessive-compulsive disorder while measuring regional cerebral blood flow with the xenon 133 inhalation technique. Each patient was studied under three conditions: relaxation, imaginal flooding, and in vivo (actual) exposure to the phobic stimulus. Subjective anxiety, obsessive-compulsive ratings, and autonomic measures (heart rate, blood pressure) increased significantly, but respiratory rate and PCO/sub 2/ did not change across the three conditions. Regional cerebral blood flow increased slightly (in the temporal region) during imaginal flooding, but decreased markedly in several cortical regions during in vivo exposure, when anxiety was highest by subjective and peripheral autonomic measures. These results demonstrate that intense anxiety can be associated with decreased rather than increased cortical perfusion and that ostensibly related states of anxiety (eg, anticipatory and obsessional anxiety) may be associated with opposite effects on regional cerebral blood flow.

  12. Evaluation of ride quality measurement procedures by subjective experiments using simulators

    Science.gov (United States)

    Klauder, L. T., Jr.; Clevenson, S. A.

    1975-01-01

    Since ride quality is, by definition, a matter of passenger response, there is need for a qualification procedure (QP) for establishing the degree to which any particular ride quality measurement procedure (RQMP) does correlate with passenger responses. Once established, such a QP will provide very useful guidance for optimal adjustment of the various parameters which any given RQMP contains. A QP is proposed based on use of a ride motion simulator and on test subject responses to recordings of actual vehicle motions. Test subject responses are used to determine simulator gain settings for the individual recordings such as to make all of the simulated rides equally uncomfortable to the test subjects. Simulator platform accelerations vs. time are recorded with each ride at its equal discomfort gain setting. The equal discomfort platform acceleration recordings are then digitzed.

  13. Serum troponin I measurement of subjects exposed to the Taser X-26.

    Science.gov (United States)

    Sloane, Christian M; Chan, Theodore C; Levine, Saul D; Dunford, James V; Neuman, Tom; Vilke, Gary M

    2008-07-01

    The Taser is a high-voltage, low-amperage conducted energy device used by many law enforcement agencies as a less lethal force weapon. The objective of this study was to evaluate for a rise in serum troponin I level after deployment of the Taser on law enforcement training volunteers. A prospective, observational cohort study was performed evaluating serum troponin I levels in human subjects 6 h after an exposure to the Taser X-26. Outcome measures included abnormal elevation in serum troponin I level (> 0.2 ng/mL). There were 66 subjects evaluated. The mean shock duration was 4.36 s (range 1.2-5 s). None of the subjects had a positive troponin I level 6 h after exposure. It was concluded that human volunteers exposed to a single shock from the Taser did not develop an abnormal serum troponin I level 6 h after shock, suggesting that there was no myocardial necrosis or infarction.

  14. Assessment of pilot workload - Converging measures from performance based, subjective and psychophysiological techniques

    Science.gov (United States)

    Kramer, Arthur F.; Sirevaag, Erik J.; Braune, Rolf

    1986-01-01

    This study explores the relationship between the P300 component of the event-related brain potential (ERP) and the processing demands of a complex real-world task. Seven male volunteers enrolled in an Instrument Flight Rule (IFR) aviation course flew a series of missions in a single engine fixed-based simulator. In dual task conditions subjects were also required to discriminate between two tones differing in frequency. ERPs time-locked to the tones, subjective effort ratings and overt performance measures were collected during two 45 min flights differing in difficulty (manipulated by varying both atmospheric conditions and instrument reliability). The more difficult flight was associated with poorer performance, increased subjective effort ratings, and smaller secondary task P300s. Within each flight, P300 amplitude was negatively correlated with deviations from command headings indicating that P300 amplitude was a sensitive workload metric both between and within the flight missions.

  15. The subjective handicap of epilepsy. A new approach to measuring treatment outcome.

    Science.gov (United States)

    O'Donoghue, M F; Duncan, J S; Sander, J W

    1998-02-01

    It is now widely acknowledged that the impact of epilepsy on the individual extends beyond the occurrence of seizures, and that there is a need for outcome measures sensitive to these consequences. Until now these instruments have largely been developed within a 'quality of life' framework. The technical and conceptual difficulties that arise with measuring quality of life have led us to develop a more focused measurement model, the 'Subjective Handicap of Epilepsy' (SHE) scale, based on the World Health Organization's concept of handicap. The scale contains 32 items in six subscales: 'Work and activities' (eight items), 'Social and personal' (four items), 'Self-perception' (five items), 'Physical' (four items), 'Life-satisfaction' (four items) and a 'Change' scale (seven items); and it takes on average handicapping effects of increasing seizure frequency, employment status, the impact of epilepsy on career choice and the subject's own opinion as to the major determinant of their quality of life. The scales were also sensitive, retrospectively, to the benefits of successful epilepsy surgery in a cohort of 105 patients. Scales focusing specifically on handicap were more sensitive to group differences in seizure frequency in the clinic population, and to outcome after epilepsy surgery, than the 'Life-satisfaction' scale and the Epilepsy Surgery Inventory 55 (ESI-55) scales. This supports the contention that measuring 'subjective handicap' may be a more sensitive, and more useful, approach to assessing the impact of interventions on the long-term consequences of epilepsy than current methods.

  16. Trismus following different treatment modalities for head and neck cancer: a systematic review of subjective measures.

    Science.gov (United States)

    Loh, Sook Y; Mcleod, Robert W J; Elhassan, Hassan A

    2017-07-01

    The aim of this review was to compare systematically the subjective measure of trismus between different interventions to treat head and neck cancer, particularly those of the oropharynx. Using The Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) Guidelines, Six databases were searched for the text using various terms which include "oropharyngeal/head and neck cancer", "trismus/mouth opening" and the various treatment modalities. Included in the review were clinical studies (> or =10 patients). Three observers independently assessed the papers identified. Among the six studies reviewed, five showed a significantly worst outcome with regard to the quality-of-life questionnaire scores for a radiotherapy or surgery and radiotherapy (RT) ± chemotherapy or chemoradiotherapy when compared to surgery alone. Only one study showed no significant difference between surgery alone and other treatment modalities. Subjective quality-of-life measures are a concurrent part of modern surgical practice. Although subjective measures were utilised to measure post operative trismus successfully, there was no consensus as to which treatment modality had overall better outcomes, with conflicting studies in keeping with the current debate in this field. Larger and higher quality studies are needed to compare all three treatment modalities.

  17. Understanding excess skin in postbariatric patients: objective measurements and subjective experiences.

    Science.gov (United States)

    Biörserud, Christina; Olbers, Torsten; Staalesen, Trude; Elander, Anna; Olsén, Monika Fagevik

    2016-08-01

    Excess skin is a well-known side effect of massive weight loss after bariatric surgery. However, there is a lack of longitudinal follow-ups. The primary aims of this study were to investigate the development and amount of excess skin after laparoscopic Roux-en-Y gastric bypass and to relate objective results to subjective experiences. University hospital. From 2009 to 2012, 200 patients were included and assessed with respect to excess skin before and 18 months after bariatric surgery. Patients were measured according to a standardized protocol and completed a questionnaire regarding their subjective experience of excess skin. A follow-up visit was completed in 149 patients (78%). All ptosis measurements decreased after weight reduction except for ptosis on the thighs. When comparing objective measurements with patients' subjective experience and discomfort from excess skin, we found little or low correlation in most body parts (rs .03-.67). The prediction analysis indicated that, for every centimeter of ptosis on the abdomen preoperatively, there was a 2-fold greater probability of having a postoperative ptosis on the abdomen of>3 cm (OR = 2.32, 1.76-3.07). The objective measurement of excess skin provides unique information in postbariatric patients' body habitus. Although the measured excess skin decreased compared with preoperative measurements, patients seem to become more aware of and disturbed and discomforted by it after the weight loss. Importantly, the objectively assessed measurements of excess skin correlated fairly with the perceived discomfort. Copyright © 2016 American Society for Bariatric Surgery. Published by Elsevier Inc. All rights reserved.

  18. Effect of a Bluetooth-implemented hearing aid on speech recognition performance: subjective and objective measurement.

    Science.gov (United States)

    Kim, Min-Beom; Chung, Won-Ho; Choi, Jeesun; Hong, Sung Hwa; Cho, Yang-Sun; Park, Gyuseok; Lee, Sangmin

    2014-06-01

    The object was to evaluate speech perception improvement through Bluetooth-implemented hearing aids in hearing-impaired adults. Thirty subjects with bilateral symmetric moderate sensorineural hearing loss participated in this study. A Bluetooth-implemented hearing aid was fitted unilaterally in all study subjects. Objective speech recognition score and subjective satisfaction were measured with a Bluetooth-implemented hearing aid to replace the acoustic connection from either a cellular phone or a loudspeaker system. In each system, participants were assigned to 4 conditions: wireless speech signal transmission into hearing aid (wireless mode) in quiet or noisy environment and conventional speech signal transmission using external microphone of hearing aid (conventional mode) in quiet or noisy environment. Also, participants completed questionnaires to investigate subjective satisfaction. Both cellular phone and loudspeaker system situation, participants showed improvements in sentence and word recognition scores with wireless mode compared to conventional mode in both quiet and noise conditions (P Bluetooth-implemented hearing aids helped to improve subjective and objective speech recognition performances in quiet and noisy environments during the use of electronic audio devices.

  19. [Contrastive analysis on soil alkalinization predicting models based on measured reflectance and TM image reflectance].

    Science.gov (United States)

    Zhang, Fang; Xiong, Hei-Gang; Long, Tao; Lu, Wen-Juan

    2011-01-01

    Based on the monitored data of soil pH and measured Vis-NIR reflectance on spot in Qitai oasis alkalinized area in Xinjiang, as well as comparison of the relationship between measured reflectance and soil pH and the relationship between TM reflectance and soil pH, both of the reflectance multivariate linear regression models were built to evaluate soil alkalinization level, and the model accuracy of pH fitting was discussed with error inspection of post-sample. The results showed that there is a significant positive correlation between soil pH and reflectance. With pH rising the reflectance increased concurrently. So the alkalinization soil characterized by hardening had good spectral response characteristics. Both measured reflectance and TM image reflectance had good potential ability for change detection of the alkalinization soil. The pH predicting model of measured reflectance had higher accuracy and the major error was from different hardening state. If building model by TM reflectance directly, the accuracy of fitting was lower because of the vegetation information in image spectrum. With the vegetation factor removed with NDVI, the accuracy of TM predicting model was near the accuracy of measured reflectance predicting model, and both of the model levels were good.

  20. Comparison between refraction measured by Spot Vision ScreeningTM and subjective clinical refractometry

    OpenAIRE

    Daniela Lima de Jesus; Flávio Fernandes Villela; Luis Fernando Orlandin; Fernando Naves Eiji; Daniel Oliveira Dantas; Milton Ruiz Alves

    2016-01-01

    OBJECTIVE: The purpose of this study was to evaluate the accuracy of Spot Vision ScreeningTM as an autorefractor by comparing refraction measurements to subjective clinical refractometry results in children and adult patients. METHODS: One-hundred and thirty-four eyes of 134 patients were submitted to refractometry by Spot and clinical refractometry under cycloplegia. Patients, students, physicians, staff and children of staff from the Hospital das Clínicas (School of Medicine, University of...

  1. Analysis of the Precautionary Saving Motive Based on a Subjective Measure : (SAVE 2005-2007)

    OpenAIRE

    Ziegelmeyer, Michael

    2009-01-01

    The importance of the precautionary saving motive for households’ saving behaviour is unquestioned in the literature of the last two decades. However, the magnitude of precautionary savings and its influencing factors could not be satisfactorily determined. A subjective measure of the desired amount of precautionary savings in the German SAVE study 2005-2007 allows for the evaluation of these questions on a new basis without relying on a specific definition of wealth. This study supports the ...

  2. Nasolabial fold angle measurement using anterior segment optical coherence tomography in normal subjects.

    Science.gov (United States)

    Lim, Marcus C C; Aung, Han T; Aung, Tin; Looi, Audrey L G

    2009-01-01

    The human nasolabial fold angle (NFA) has been measured using MRI and photogrammetry and has been shown to decrease with age. The authors aimed to evaluate a novel method using optical coherence tomography to measure the NFA. In this cross-sectional observational series, the authors used anterior segment optical coherence tomography (ASOCT) to image the NFA of both cheeks of 126 subjects aged 21 to 79 years. A dental vinylpolysiloxane custom-designed mould was used as a chin rest. The mean of 3 scans on each side was calculated and analysis of variance, multiple comparisons, and multiple linear regression were carried out using SPSS 11.0. Sixty-one subject (48.4%) were men and 65 (51.6%) were women. Mean age was 50.6 +/- 16.8 years (range, 21-79 years). The ASOCT successfully imaged the NFA in all subjects. Mean right and left NFA were 144.4 degrees +/- 17.1 degrees and 145.4 degrees +/- 17.7 degrees. The NFA were dissimilar between the 6 age categories by decade (p NFA, accounting for 55% of NFA variation. Every year accounted for a decrease of 0.78 degrees (p NFA of 5.4 degrees (p = 0.007) and 4.0 degrees (p = 0.06) in the right and left cheeks, respectively. The NFA decreases with age and increases with male sex and can be measured with ASOCT accurately and easily.

  3. Can subjective comfort be used as a measure of plantar pressure in football boots?

    Science.gov (United States)

    Okholm Kryger, Katrine; Jarratt, Vicky; Mitchell, Séan; Forrester, Steph

    2017-05-01

    Comfort has been shown to be the most desired football boot feature by players. Previous studies have shown discomfort to be related to increased plantar pressures for running shoes which, in some foot regions, has been suggested to be a causative factor in overuse injuries. This study examined the correlation between subjective comfort data and objective plantar pressure for football boots during football-specific drills. Eight male university football players were tested. Plantar pressure data were collected during four football-specific movements for each of three different football boots. The global and local peak pressures based on a nine-sectioned foot map were compared to subjective comfort measures recorded using a visual analogue scale for global discomfort and a discomfort foot map for local discomfort. A weak (rs = -0.126) yet significant (P comfort. The model only significantly predicted (P > 0.001) the outcome for two (medial and lateral forefoot) of the nine foot regions. Subjective comfort data is therefore not a reliable measure of increased plantar pressures for any foot region. The use of plantar pressure measures is therefore needed to optimise injury prevention when designing studded footwear.

  4. Adaptation profiles comprising objective and subjective measures in fibromyalgia: the al-Ándalus project.

    Science.gov (United States)

    Estévez-López, Fernando; Segura-Jiménez, Víctor; Álvarez-Gallardo, Inmaculada C; Borges-Cosic, Milkana; Pulido-Martos, Manuel; Carbonell-Baeza, Ana; Aparicio, Virginia A; Geenen, Rinie; Delgado-Fernández, Manuel

    2017-11-01

    The aim of this study was to identify subgroups in terms of adaptation to FM and to test differences in FM severity between these subgroups. The al-Ándalus project made it possible to perform a comprehensive population-based cross-sectional study in 486 FM patients including multiple assessments of modifiable (could be targeted in therapy) resilience and vulnerability factors, measured by objective and subjective assessments, related to psychological and physical function. FM severity was assessed by means of FM impact (total score of the Revised Fibromyalgia Impact Questionnaire) and distress (Polysymptomatic Distress Scale of the modified 2011 preliminary criteria for FM). Exploratory factor analysis, cluster analysis and analysis of variance were conducted. Factor analysis yielded eight factors: three included objective measures (declarative memory, active lifestyle and objective physical fitness) and five included subjective measures (fatigue, psychological distress, catastrophizing, resilience and subjective physical fitness). Cluster analysis based on these eight factors identified five profiles: Adapted (16%), Fit (18%), Poor performer (20%), Positive (20%) and Maladapted (26%). Most profile comparisons revealed different levels of FM severity varying from Adapted (the most favourable profile) to Maladapted (the most unfavourable profile) with Fit, Poor performer and Positive obtaining intermediate positions. Heterogeneity of FM was shown by five clinically meaningful profiles of modifiable factors that were associated with FM severity. It is of clinical interest to examine whether these profiles are associated with FM prognosis and the effectiveness of interventions, which would enhance the development of customized interventions based on adaptation profiles in FM.

  5. Fractionating impulsivity: contrasting effects of central 5-HT depletion on different measures of impulsive behavior.

    Science.gov (United States)

    Winstanley, Catharine A; Dalley, Jeffrey W; Theobald, David E H; Robbins, Trevor W

    2004-07-01

    Reducing levels of 5-HT in the central nervous system has been associated with increases in impulsive behavior. However, the impulsivity construct describes a wide range of behaviors, including the inability to withhold a response, intolerance to delay of reward and perseveration of a nonrewarded response. Although these behaviors are generally studied using instrumental paradigms, impulsivity may also be reflected in simple Pavlovian tasks such as autoshaping and conditioned activity. This experiment aimed to characterize further the effects of central 5-HT depletion and to investigate whether different behavioral measures of impulsivity are inter-related, thus validating the construct. Rats received intracerebroventricular (ICV) infusions of vehicle (n=10) or the serotonergic neurotoxin 5,7-dihydroxytryptamine (n=12) which depleted forebrain 5-HT levels by about 90%. Lesioned animals showed significant increases in the speed and number of responses made in autoshaping, increased premature responding on a simple visual attentional task, enhanced expression of locomotor activity conditioned to food presentation, yet no change in impulsive choice was observed, as measured by a delay-discounting paradigm. Significant positive correlations were found between responses made in autoshaping and the level of conditioned activity, indicating a possible common basis for these behaviors, yet no correlations were found between other behavioral measures. These data strengthen and extend the hypothesis that 5-HT depletion increases certain types of impulsive responding. However, not all measures of impulsivity appear to be uniformly affected by 5-HT depletion, or correlate with each other, supporting the suggestion that impulsivity is not a unitary construct. Copyright 2004 Nature Publishing Group

  6. Comparison of different pointing methods for sound localizability measurement in the vision impaired subjects.

    Science.gov (United States)

    Fujii, Atsunori; Ohsugi, Yudai; Yamamoto, Yuki; Nakamura, Takabun; Sugiura, Toshifumi; Tauchi, Masaki

    2007-05-01

    In order to find out the most suitable and accurate pointing methods to study the sound localizability of persons with visual impairment, we compared the accuracy of three different pointing methods for indicating the direction of sound sources in a semi-anechoic dark room. Six subjects with visual impairment (two totally blind and four with low vision) participated in this experiment. The three pointing methods employed were (1) directing the face, (2) directing the body trunk on a revolving chair and (3) indicating a tactile cue placed horizontally in front of the subject. Seven sound emitters were arranged in a semicircle 2.0 m from the subject, 0 degrees to +/-80 degrees of the subject's midline, at a height of 1.2 m. The accuracy of the pointing methods was evaluated by measuring the deviation between the angle of the target sound source and that of the subject's response. The result was that all methods indicated that as the angle of the sound source increased from midline, the accuracy decreased. The deviations recorded toward the left and the right of midline were symmetrical. In the whole frontal area (-80 degrees to +80 degrees from midline), both the tactile cue and the body trunk methods were more accurate than the face-pointing method. There was no significant difference in the center (-40 degrees to +40 degrees from midline). In the periphery (-80 degrees and +80 degrees ), the tactile cue pointing method was the most accurate of all and the body trunk method was the next best. These results suggest that the most suitable pointing methods to study the sound localizability of the frontal azimuth for subjects who are visually impaired are the tactile cue and the body trunk methods because of their higher accuracy in the periphery.

  7. Measurement and simulation of ICRF wave intensity with a recalibrated phase contrast imaging diagnostic on Alcator C-Mod

    Energy Technology Data Exchange (ETDEWEB)

    Tsujii, N., E-mail: tsujii@k.u-tokyo.ac.jp [The University of Tokyo, Kashiwa (Japan); Porkolab, M.; Bonoli, P. T.; Edlund, E. M.; Ennever, P. C.; Lin, Y.; Wright, J. C.; Wukitch, S. J. [MIT Plasma Science and Fusion Center, Cambridge, Massachusetts (United States); Jaeger, E. F. [XCEL Engineering, Oak Ridge, Tennessee (United States); Green, D. L. [Oak Ridge National Laboratory, Oak Ridge, Tennessee (United States); Harvey, R. W. [CompX, Del Mar, California (United States)

    2015-12-10

    Waves in the ion cyclotron range of frequencies (ICRF) are one of the major tools to heat fusion plasmas. Full-wave simulations are essential to predict the wave propagation and absorption quantitatively, and it is important that these codes be validated against actual experimental measurements. In this work, the absolute intensity of the ICRF waves previously measured with a phase contrast imaging diagnostic was recalibrated and compared once more with full-wave predictions. In the earlier work, significant discrepancies were found between the measured and the simulated mode converted wave intensity [N. Tsujii et al., Phys. Plasmas 19, 082508]. With the new calibration of the detector array, the measured mode converted wave intensity is now in much better agreement with the full-wave predictions. The agreement is especially good for comparisons performed close to the antenna.

  8. Measurement and simulation of ICRF wave intensity with a recalibrated phase contrast imaging diagnostic on Alcator C-Mod

    Science.gov (United States)

    Tsujii, N.; Porkolab, M.; Bonoli, P. T.; Edlund, E. M.; Ennever, P. C.; Lin, Y.; Wright, J. C.; Wukitch, S. J.; Jaeger, E. F.; Green, D. L.; Harvey, R. W.

    2015-12-01

    Waves in the ion cyclotron range of frequencies (ICRF) are one of the major tools to heat fusion plasmas. Full-wave simulations are essential to predict the wave propagation and absorption quantitatively, and it is important that these codes be validated against actual experimental measurements. In this work, the absolute intensity of the ICRF waves previously measured with a phase contrast imaging diagnostic was recalibrated and compared once more with full-wave predictions. In the earlier work, significant discrepancies were found between the measured and the simulated mode converted wave intensity [N. Tsujii et al., Phys. Plasmas 19, 082508]. With the new calibration of the detector array, the measured mode converted wave intensity is now in much better agreement with the full-wave predictions. The agreement is especially good for comparisons performed close to the antenna.

  9. The Evolution of Eupathics: The Historical Roots of Subjective Measures of Wellbeing

    Directory of Open Access Journals (Sweden)

    Erik Angner

    2011-01-01

    Full Text Available

    This paper traces the historical roots of subjective measures of wellbeing, that is, measures designed to represent happiness, satisfaction, or other “positive” or desirable mental states. While it is often suggested that these measures are a modern invention, I argue that they have a long and rich history that conforms to Theodore M. Porter’s general account of measurement in social and behavioral science. Subjective measures emerged in marital success studies, educational psychology, and personality psychology in the 1920s and 30s, and were further shaped by the epidemiology of mental health, gerontology, and the social indicator movement in the 1960s and 70s. Consistent with Porter’s account, these measures emerged in applied rather than theoretical branches of social and behavioral science, and they did so not as a result of physics envy, but rather as a result of a moral impulse to improve society; quantification was intended to make up for perceived deficiencies in unaided human judgment; and radical disagreements about the nature of wellbeing did not impede efforts to measure it – indeed, in time, there was considerably more agreement about how to measure wellbeing than about how to define it.

  10. Quantification of the effect of water exchange in dynamic contrast MRI perfusion measurements in the brain and heart

    DEFF Research Database (Denmark)

    Larsson, H B; Rosenbaum, S; Fritz-Hansen, T

    2001-01-01

    Measurement of myocardial and brain perfusion when using exogenous contrast agents (CAs) such as gadolinium-DTPA (Gd-DTPA) and MRI is affected by the diffusion of water between compartments. This water exchange may have an impact on signal enhancement, or, equivalently, on the longitudinal......(i)) by using a realistic simulation. These results were verified by in vivo studies of the heart and brain in humans. The conclusion is that water exchange between the vascular and extravascular extracellular space has no effect on K(i) estimation in the myocardium when a normal dose of Gd-DTPA is used. Water...... exchange can have a significant effect on perfusion estimation (F) in the brain when using Gd-DTPA, where it acts as an intravascular contrast agent....

  11. The reliability of side to side measurements of upper extremity activity levels in healthy subjects

    Directory of Open Access Journals (Sweden)

    Amasay Tal

    2010-07-01

    Full Text Available Abstract Background In both clinical and occupational settings, ambulatory sensors are becoming common for assessing all day measurements of arm motion. In order for the motion of a healthy, contralateral side to be used as a control for the involved side, the inherent side to side differences in arm usage must be minimal. The goal of the present study was to determine the reliability of side to side measurements of upper extremity activity levels in healthy subjects. Methods Thirty two subjects with no upper extremity pathologies were studied. Each subject wore a triaxial accelerometer on both arms for three and a half hours. Motion was assessed using parameters previously reported in the literature. Side to side differences were compared with the intraclass correlation coefficient, standard error of the mean, minimal detectable change scores and a projected sample size analysis. Results The variables were ranked based on their percentage of minimal detectable change scores and sample sizes needed for paired t-tests. The order of these rankings was found to be identical and the top ranked parameters were activity counts per hour (MDC% = 9.5, n = 5, jerk time (MDC% = 15.8, n = 8 and percent time above 30 degrees (MDC% = 34.7, n = 9. Conclusions In general, the mean activity levels during daily activities were very similar between dominant and non-dominant arms. Specifically, activity counts per hour, jerk time, and percent time above 30 degrees were found to be the variables most likely to reveal significant difference or changes in both individuals and groups of subjects. The use of ambulatory measurements of upper extremity activity has very broad uses for occupational assessments, musculoskeletal injuries of the shoulder, elbow, wrist and hand as well as neurological pathologies.

  12. Dynamic contrast-enhanced x-ray CT measurement of cerebral blood volume in a rabbit tumor model

    Science.gov (United States)

    Cenic, Aleksa; Lee, Ting-Yim; Craen, Rosemary A.; Gelb, Adrian W.

    1998-07-01

    Cerebral blood volume (CBV) is a major determinant of intracranial pressure (ICP). Hyperventilation is commonly employed to reduce raised ICP (e.g. in brain tumour patients) presumably through its effect on CBV. With the advent of slip- ring CT scanners, dynamic contrast-enhanced imaging allows for the measurement of CBV with high spatial resolution. Using a two-compartment model to characterize the distribution of X- ray contrast agent in the brain, we have developed a non- equilibrium CT method to measure CBV in normal and pathological regions. We used our method to investigate the effect of hyperventilation on CBV during propofol anaesthesia in rabbits with implanted brain tumours. Eight New Zealand White rabbits with implanted VX2 carcinoma brain tumours were studied. For each rabbit, regional CBV measurements were initially made at normocapnia (PaCO2 40 mmHg) and then at hyperventilation (PaCO2 25 mmHg) during propofol anaesthesia. The head was positioned such that a coronal image through the brain incorporated a significant cross-section of the brain tumour as well as a radial artery in a forelimb. Images at the rate of 1 per second were acquired for 2 minutes as Omnipaque 300 (1.5 ml/kg rabbit weight) was injected via a peripheral vein. In these CT images, regions of interest in the brain tissue (e.g. tumour, contra-lateral normal, and peri-tumoural) and the radial artery were drawn. For each region, the mean CT number in pre-contrast images was subtracted from the mean CT number in post-contrast images to produce either the tissue contrast concentration curve, or the arterial contrast concentration curve. Using our non- equilibrium analysis method based on a two-compartment model, regional CBV values were determined from the measured contrast concentration curves. From our study, the mean CBV values [+/- SD] in the tumour, peri-tumoural, and contra-lateral normal regions during normocapnia were: 5.47 plus or minus 1.97, 3.28 plus or minus 1.01, and 1

  13. Measurements of potential differences in human subjects induced by motion in a superconducting magnetic field.

    Science.gov (United States)

    Frinak, S; Knight, R A; Liboff, A R

    1992-01-01

    We have attempted to measure the electromotive forces (emfs) induced in human beings moving at a constant speed in a highly dense magnetic field. Experiments were initially conducted on a set of models, and then directly on human subjects. The models consisted of single circular loops of Tygon tubing (I.D., 0.635 cm; O.D., 0.9525 cm) filled with normal saline solution, with circumferences of 20, 40, 60, 80, and 100 cm. The models were connected to an amplifier via silver/silver-chloride electrodes. Each saline loop was mounted on a movable platform, with the plane of the loop perpendicular to the platform's axis; the platform was enabled to move at known constant speeds into and out of the bore of a 1.89-T magnet. The human subjects were then substituted for the saline loops, with the long axis parallel to the direction of motion, and with standard EKG electrodes placed at 180 degrees successively on the ankle, calf, lower thigh, upper thigh, chest, and head. In all cases, for human subjects and models, the peak induced voltage was directly proportional to the speed of movement and the square of the circumference of the bounded cross-sectional areas. Thus, for the saline loops, the correlation coefficient between induced voltage and circumference was .998, and for human subjects, .947. Under the loose assumption that for equal circumferences the bounded areas in human subjects were equal to those in the circular loops, the induced emfs in human subjects were consistently about 13% greater than those in the loops. At a mean speed of 1.18 m/s, the chest had a peak induced voltage of 260 mV, while the voltage at the ankle had a peak of 19.8 mV. The experimental data were used to estimate the corresponding induced-current density at the pericardium, 17 mA/m2. We conclude for a human subject moving at constant speed along the body's long axis into a magnetic field that Faraday's law is closely followed for various cross-sections of the body. Further, in those cases in

  14. Validation of subject-specific cardiovascular system models from porcine measurements.

    Science.gov (United States)

    Revie, James A; Stevenson, David J; Chase, J Geoffrey; Hann, Christopher E; Lambermont, Bernard C; Ghuysen, Alexandre; Kolh, Philippe; Shaw, Geoffrey M; Heldmann, Stefan; Desaive, Thomas

    2013-02-01

    A previously validated mathematical model of the cardiovascular system (CVS) is made subject-specific using an iterative, proportional gain-based identification method. Prior works utilised a complete set of experimentally measured data that is not clinically typical or applicable. In this paper, parameters are identified using proportional gain-based control and a minimal, clinically available set of measurements. The new method makes use of several intermediary steps through identification of smaller compartmental models of CVS to reduce the number of parameters identified simultaneously and increase the convergence stability of the method. This new, clinically relevant, minimal measurement approach is validated using a porcine model of acute pulmonary embolism (APE). Trials were performed on five pigs, each inserted with three autologous blood clots of decreasing size over a period of four to five hours. All experiments were reviewed and approved by the Ethics Committee of the Medical Faculty at the University of Liege, Belgium. Continuous aortic and pulmonary artery pressures (P(ao), P(pa)) were measured along with left and right ventricle pressure and volume waveforms. Subject-specific CVS models were identified from global end diastolic volume (GEDV), stroke volume (SV), P(ao), and P(pa) measurements, with the mean volumes and maximum pressures of the left and right ventricles used to verify the accuracy of the fitted models. The inputs (GEDV, SV, P(ao), P(pa)) used in the identification process were matched by the CVS model to errors pressures not used to fit the model compared experimental measurements to median absolute errors of 4.3% and 4.4%, which are equivalent to the measurement errors of currently used monitoring devices in the ICU (∼5-10%). These results validate the potential for implementing this approach in the intensive care unit. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  15. A new device for measuring resting energy expenditure (REE) in healthy subjects.

    Science.gov (United States)

    Malavolti, Marcella; Pietrobelli, Angelo; Dugoni, Manfredo; Poli, Marco; Romagnoli, Elisa; De Cristofaro, Paolo; Battistini, Nino C

    2007-06-01

    Lifestyle change targeted towards increasing daily resting energy expenditure (REE) is one of the cornerstones of obesity treatment. Measurements of energy expenditure and substrate utilization are essential to understanding the metabolic basis of obesity, and the physiological responses to perturbations in habitual food intake. REE is the largest part of human energy expenditure (60-70%) and an increase or decrease in REE would have a large impact on total energy. Accurate and easy-to-use methods for measuring REE are needed, to be applied by clinicians in daily clinical settings to assess the validity of a new instrument to estimate REE in normal weight, healthy adults. Ninety-nine subjects (52 females and 47 males) (mean+/-SD, age 38+/-14 years; body mass index (BMI) 23+/-3 kg/m(2)) were tested. REE was assessed using a Sensor Medics Vmax metabolic cart with a ventilated canopy and with the SenseWear armband. Body composition, percentage fat mass (%FM) and percentage fat free mass (%FFM) were assessed by skinfold thickness measurements (SF), bio-electrical impedance analysis (BIA) and air displacement plethysmography (BOD-POD). No significant difference was found among measurements of FFM using the three different techniques. Both SenseWear and Sensor Medics Vmax showed a high correlation, r=0.42 and r=0.40 (pBOD-POD correlated with SenseWear (r=0.42, pBOD-POD provide valid and reliable measurements of FFM. Our results suggest that the SenseWear armband is an acceptable device to accurately measure REE in healthy subjects. Its characteristics have the potential to reduce measurement times and make the SenseWear armband useful for epidemiological studies.

  16. Is there an association between subjective and objective measures of cognitive function in patients with affective disorders?

    DEFF Research Database (Denmark)

    Svendsen, Anne M; Kessing, Lars V; Munkholm, Klaus

    2012-01-01

    Background: Patients with affective disorders experience cognitive dysfunction in addition to their affective symptoms. The relationship between subjectively experienced and objectively measured cognitive function is controversial with several studies reporting no correlation between subjective...... and objective deficits. Aims: To investigate whether there is a correlation between subjectively reported and objectively measured cognitive function in patients with affective disorders, and whether subjective complaints predict objectively measured dysfunction. Methods: The study included 45 participants; 15...... with bipolar disorder (BD), 15 with unipolar disorder (UD) and 15 healthy individuals. Participants' subjectively experienced cognitive function and objective cognitive function were assessed with the Massachusetts General Hospital Cognitive and Physical Functioning Questionnaire (CPFQ) and the Screen...

  17. Measuring executive function in control subjects and TBI patients with question completion time (QCT).

    Science.gov (United States)

    Woods, David L; Yund, E William; Wyma, John M; Ruff, Ron; Herron, Timothy J

    2015-01-01

    Questionnaire completion is a complex task that places demands on cognitive functions subserving reading, introspective memory, decision-making, and motor control. Although computerized questionnaires and surveys are used with increasing frequency in clinical practice, few studies have examined question completion time (QCT), the time required to complete each question. Here, we analyzed QCTs in 172 control subjects and 31 patients with traumatic brain injury (TBI) who completed two computerized questionnaires, the 17-question Post-Traumatic Stress Disorder (PTSD) Checklist (PCL) and the 25-question Cognitive Failures Questionnaire (CFQ). In control subjects, robust correlations were found between self-paced QCTs on the PCL and CFQ (r = 0.82). QCTs on individual questions correlated strongly with the number of words in the question, indicating the critical role of reading speed. QCTs increased significantly with age, and were reduced in females and in subjects with increased education and computer experience. QCT z-scores, corrected for age, education, computer use, and sex, correlated more strongly with each other than with the results of other cognitive tests. Patients with a history of severe TBI showed significantly delayed QCTs, but QCTs fell within the normal range in patients with a history of mild TBI. When questionnaires are used to gather relevant patient information, simultaneous QCT measures provide reliable and clinically sensitive measures of processing speed and executive function.

  18. The kinetic and kinematic stability measures in healthy adult subjects with and without flat foot.

    Science.gov (United States)

    Sung, Paul S; Zipple, J Timothy; Andraka, John M; Danial, Pamela

    2017-03-01

    Flat foot problems are associated with impaired mobility and postural stability. The purpose of this study was to compare the kinematic and kinetic indices during one leg standing between subjects with and without flat foot. Forty-four participants enrolled in the study, including 22 subjects with flat foot and 22 control subjects. The measurements included kinematic stability on the trunk as well as kinetic stability from a force plate. All participants were asked to maintain one leg standing with the contralateral hip and knee flexed to approximately 90° for 25seconds. The kinetic index decreased in the flat foot group (t=-5.08, p=0.001) during one leg standing without visual input. There were strong correlations between kinetic and kinematic stabilities (0.75-0.86) with visual input and moderate correlations (0.49-0.67) without visual input in the control group. The flat foot group exhibited a significantly decreased kinetic index without visual input. The more effective postural stability in the control group might be due to efficient compensatory strategies utilized without visual input to maintain one leg standing. These outcome measures could help to develop a practical test leading to kinematic postural changes. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Comprehensive list of metabolites measured by DI-FTICR mass spectrometry in thyme plants with contrasting tolerance to drought

    Directory of Open Access Journals (Sweden)

    Parviz Moradi

    2017-06-01

    Full Text Available This article contains data related to the main research entitled “Metabolomic approach reveals the biochemical mechanisms underlying drought stress tolerance in Thyme” (Moradi et al., 2017 [1]. Two thyme populations with contrasting drought tolerance were subjected to long term water deficit. Leaf samples harvested at the end of stress period and bi-phasic extraction carried out to get polar and non-polar fractions. Extracted samples were analyzed through Direct Infusion FT-ICR mass spectrometry. Date files comprise of four separate tables for all the putatively identified metabolites and their intensities in watered and droughted plants. P-values beside each m/z values indicate significances of difference between peak intensities of stressed and control conditions.

  20. Contrasting Complement Control, Temporal Adjunct Control and Controlled Verbal Gerund Subjects in ASD: The Role of Contextual Cues in Reference Assignment.

    Science.gov (United States)

    Janke, Vikki; Perovic, Alexandra

    2017-01-01

    This study examines two complex syntactic dependencies (complement control and sentence-final temporal adjunct control) and one pragmatic dependency (controlled verbal gerund subjects) in children with ASD. Sixteen high-functioning (HFA) children (aged 6-16) with a diagnosis of autism and no language impairment, matched on age, gender and non-verbal MA to one TD control group, and on age, gender and verbal MA to another TD control group, undertook three picture-selection tasks. Task 1 measured their base-line interpretations of the empty categories (ec). Task 2 preceded these sentence sets with a weakly established topic cueing an alternative referent and Task 3 with a strongly established topic cueing an alternative referent. In complement control (Ron persuaded Hermione ec to kick the ball) and sentence-final temporal adjunct control (Harry tapped Luna while ec feeding the owl), the reference of the ec is argued to be related obligatorily to the object and subject respectively. In controlled verbal-gerund subjects (VGS) (ec Rowing the boat clumsily made Luna seasick), the ec's reference is resolved pragmatically. Referent choices across the three tasks were compared. TD children chose the object uniformly in complement control across all tasks but in adjunct control, preferences shifted toward the object in Task 3. In controlled VGSs, they exhibited a strong preference for an internal-referent interpretation in Task 1, which shifted in the direction of the cues in Tasks 2 and 3. HFA children gave a mixed performance. They patterned with their TD counterparts on complement control and controlled VGSs but performed marginally differently on adjunct control: no TD groups were influenced by the weakly established topic in Task 2 but all groups were influenced by the strongly established topic in Task 3. HFA children were less influenced than the TD children, resulting in their making fewer object choices overall but revealing parallel patterns of performance. In this

  1. A review of subjective impact measures for use with children and adolescents with epilepsy.

    Science.gov (United States)

    Cowan, Justin; Baker, Gus A

    2004-10-01

    To evaluate measures of epilepsy-specific impact currently available for use with children and adolescents. The relative merits of the different measures are examined. Four published epilepsy-specific impact measures, the Epilepsy and Learning Disabilities Quality of Life Scale (ELDQOL), the Health-related Quality of Life in Children with Epilepsy (HRQoLCE); the Impact of Childhood Neurologic Disability Scale (ICND), the Quality of Life in Epilepsy Inventory for Adolescents (QOLIE-AD-48), and the Quality of Life for Children with Epilepsy (QOLCE) were reviewed. There exist several shortcomings with the available measures on various psychometric criteria with not one of the currently available measures reaching acceptable psychometric standards in terms of reliability and validity. Of note are the particular inadequacies in the validation of scale content; with there being no investigation of the existence of age or ability effects for the items in any of the questionnaires reviewed. There is a clear demand for a psychometrically robust measure of subjective impact of epilepsy for children and adolescents, which is applicable to a wide age and ability range. At present, the efforts of the Canadian Pediatric Epilepsy Network with the recent publication of a novel measure holds much promise for the future. It is advocated that further efforts are made to further establish the psychometric properties of these scales and for their integration within a comprehensive outcome model for use in the evaluation of clinical interventions.

  2. Subjective and objective measurement of websites quality in a chemical industry

    Directory of Open Access Journals (Sweden)

    Julius Jillbert

    2014-10-01

    Full Text Available This paper assesses the Website of a chemical company, Deza, relative to strategy and Website quality. In an attempt to obtain both an objective and subjective measure of the quality of the Deza website, two assessment methods have been used. Firstly, a subjective assessment was conducted based on the WebQual survey instrument proposed by Barnes and Vidgen (2000. Secondly, a more objective assessment was conducted via an “informational content analysis”, based on the work of Carlson et. al. (2001. Analysis of the results of the WebQual survey suggest that overall, the Deza Website is perceived by the user as being of a higher quality than the Koppers Website, but a lower quality then the Nalon Website. The Information content analysis also ranks the Deza website as being superior to Koppers and inferior to Nalon.

  3. Testing different decoupling coefficients with measurements and models of contrasting canopies and soil water conditions

    Directory of Open Access Journals (Sweden)

    V. Goldberg

    2008-07-01

    Full Text Available Four different approaches for the calculation of the well established decoupling coefficient Ω are compared using measurements at three experimental sites (Tharandt – spruce forest, Grillenburg and Melpitz – grass and simulations from the soil-vegetation boundary layer model HIRVAC. These investigations aimed to quantify differences between the calculation routines regarding their ability to describe the vegetation-atmosphere coupling of grass and forest with and without water stress.

    The model HIRVAC used is a vertically highly resolved atmospheric boundary layer model, which includes vegetation. It is coupled with a single-leaf gas exchange model to simulate physiologically based reactions of different vegetation types to changing atmospheric conditions. A multilayer soil water module and a functional parameterisation are the base in order to link the stomata reaction of the gas exchange model to the change of soil water.

    The omega factor was calculated for the basic formulation according to McNaughton and Jarvis (1983 and three modifications. To compare measurements and simulations for the above mentioned spruce and grass sites, the summer period 2007 as well as a dry period in June 2000 were used. Additionally a developing water stress situation for three forest canopies (spruce, pine and beech and for a grass site was simulated. The results showed large differences between the different omega approaches which depend on the vegetation type and the soil moisture.

    Between the omega values, which were calculated by the used approach, the ranking was always the same not only for the measurements but also for the adapted simulations. The lowest values came from the first modification including doubling factors and summands in all parts of omega equation in relation to the original approach. And the highest values were calculated with the second modification missing one doubling factor in the denominator of the

  4. Comparison of subjective and fully automated methods for measuring mammographic density.

    Science.gov (United States)

    Moshina, Nataliia; Roman, Marta; Sebuødegård, Sofie; Waade, Gunvor G; Ursin, Giske; Hofvind, Solveig

    2018-02-01

    Background Breast radiologists of the Norwegian Breast Cancer Screening Program subjectively classified mammographic density using a three-point scale between 1996 and 2012 and changed into the fourth edition of the BI-RADS classification since 2013. In 2015, an automated volumetric breast density assessment software was installed at two screening units. Purpose To compare volumetric breast density measurements from the automated method with two subjective methods: the three-point scale and the BI-RADS density classification. Material and Methods Information on subjective and automated density assessment was obtained from screening examinations of 3635 women recalled for further assessment due to positive screening mammography between 2007 and 2015. The score of the three-point scale (I = fatty; II = medium dense; III = dense) was available for 2310 women. The BI-RADS density score was provided for 1325 women. Mean volumetric breast density was estimated for each category of the subjective classifications. The automated software assigned volumetric breast density to four categories. The agreement between BI-RADS and volumetric breast density categories was assessed using weighted kappa (k w ). Results Mean volumetric breast density was 4.5%, 7.5%, and 13.4% for categories I, II, and III of the three-point scale, respectively, and 4.4%, 7.5%, 9.9%, and 13.9% for the BI-RADS density categories, respectively ( P for trend density categories was k w  = 0.5 (95% CI = 0.47-0.53; P density increased with increasing density category of the subjective classifications. The agreement between BI-RADS and volumetric breast density categories was moderate.

  5. Response of current phosphorus mitigation measures across the nutrient transfer continuum in two hydrological contrasting agricultural catchments

    Science.gov (United States)

    McDonald, Noeleen; Shore, Mairead; Mellander, Per-Erik; Shortle, Ger; Jordan, Phil

    2015-04-01

    Effective assessment of National Action Programme (NAP) measures introduced under the EU Nitrates Directive (ND), to manage nutrient use and risk of loss to waters from agriculture, is best achieved when examined across the nutrient transfer continuum at catchment scale. The Irish NAP measures are implemented on a whole-territory basis for both nitrogen (N) and phosphorus (P), with P being the key trophic pressure. The aim of this research was to observe the efficacy of P regulation measures and P source management across the transfer continuum and resultant water quality status (i.e. source to impact), in two contrasting agricultural catchments over a four year period. The catchments are ca. 11 km2 and are located in the south-east of Ireland. One is well-drained and arable dominated, while the other is mostly poorly-drained and grassland dominated. In 2009 and 2013 soil surveys for plant-available P were carried out (agricultural catchments.

  6. Beyond standard quality of life measures: the subjective experiences of living with inflammatory bowel disease.

    Science.gov (United States)

    Wolfe, Barat J; Sirois, Fuschia M

    2008-08-01

    In order to facilitate our understanding of health-related quality of life (HRQoL) for inflammatory bowel disease (IBD) patients, it is critical to explore their subjective experiences with the disease. Research has suggested that current modes of assessing HRQoL (i.e., generic and disease-specific measures) may not fully represent all dimensions of patients' HRQoL. The purpose of this study was to examine IBD patients' subjective experiences of the daily impact of IBD, and categorize dimensions of their HRQoL affected by IBD, as identified by the patients themselves. Two hundred and eighty-two patients with IBD provided answers to the qualitative question "How has IBD affected your daily activities?" A content analysis using NVivo 2.0 was conducted on the participants' responses to this question to reveal dimensions of their HRQoL. The analysis yielded six dimensions and several subdimensions of HRQoL, including physical (systemic functioning, daily functioning, energy/vitality, pain), emotional, social, cognitive (functioning, attending to disease), self-regulation (taking control, loss of control, and neutral), and practical functioning. These results reflect previous findings, but also reveal several dimensions of HRQoL not included in current measures of HRQoL for IBD patients (i.e., cognitive, self-regulation, and practical). The implications of these findings for future measurement of HRQoL and research with IBD patients are discussed.

  7. Measurement of cortisol and testosterone in hair of obese and non-obese human subjects.

    Science.gov (United States)

    Chan, J; Sauvé, B; Tokmakejian, S; Koren, G; Van Uum, S

    2014-06-01

    Hair analysis has been demonstrated to accurately reflect exposure to drug abuse, environmental toxins and exogenous hormones. We tested the feasibility of measuring cortisol and testosterone in hair of healthy and obese subjects. A modified immunoassay (ELISA) originally developed for saliva was used. Hair, urine and blood samples were collected from young non-obese and obese patients. Perceived stress (PSS) was measured using a validated questionnaire. There was no difference in PSS between non-obese and obese subjects. Hair cortisol levels were significantly correlated with weight (r = 0.27, p significance (p = 0.063). Hair cortisol levels did not correlate with age or urinary cortisol. There was a negative correlation between hair testosterone and age (r = -0.47, p significance (p = 0.098). The ratio of hair cortisol over hair testosterone (C/T) was higher in the obese group than in the young non-obese group. The C/T ratio correlated positively with age (r = 0.56, p significance. Hair cortisol levels increase, while hair testosterone levels decrease with obesity. The hair C/T ratio was significantly correlated with age, BMI and waist circumference better than hair cortisol or testosterone alone. As hair collection is non-invasive and is not influenced by moment-to-moment variations, the measurement of hormones in hair is a useful tool in research and possibly clinical practice. © Georg Thieme Verlag KG Stuttgart · New York.

  8. Translating data and measurements from stratus to cirrus OCT in glaucoma patients and healthy subjects.

    Science.gov (United States)

    Chiseliţă, Dorin; Pantalon, Anca Delia; Cantemir, Alina; Gălăţanu, Cătălina

    2016-01-01

    Aim: our study tried to find a mathematical conversion method of the measurements obtained in Time Domain (TD) OCT to Spectral Domain (SD) OCT. Material and method: A prospective randomized, double blind study that included 244 eyes, from 121 patients (normal subjects, glaucoma suspects, glaucoma), in whom we analyzed the retinal nerve fiber layer (RNFL) and the optic disc in the same session by using TD OCT (Stratus) and SD OCT (Cirrus), was performed. The means for RNFL thickness (overall value and per quadrants), neural area and cup/ disc (C/ D) ratio, were measured. Results: We found statistically significant differences between parameters measured in TD OCT and SD OCT (pOCT machines. Data dispersion showed a linear relation between measurements. One can use the following mathematical equations for conversion: Mean RNFL (Cirrus) = 15.77 + 0.748 x Mean RNFL (Stratus) Mean neural area (Cirrus) = 0.508 + 0.388 x Mean neural area (Stratus) Mean C/ D ratio (Cirrus) = 0.157 + 0.792 x Mean C/ D (Stratus) Conclusions: data based on our calculated mathematical conversion equations can be converted into SD OCT. Therefore, we offered a useful tool for the long term monitoring of our patients although the initial measurements in TD OCT made comparisons for patients later measured with SD OCT impossible. Abbreviations: RNFL = retinal nerve fiber layer, TD OCT = time domain optical coherence tomography, SD OCT = spectral domain optical coherence tomography, VF = visual field, CI = confidence interval, ISNT segments = inferior, superior, nasal, temporal segment.

  9. Measurements of exhaled nitric oxide in healthy subjects age 4 to 17 years

    DEFF Research Database (Denmark)

    Buchvald, Frederik; Baraldi, Eugenio; Carraro, Silvia

    2005-01-01

    NO was measured in healthy subjects of 4 to 17 years according to American Thoracic Society guidelines (single breath online, exhalation flow 50 mL/s) with a chemiluminescence analyzer (NIOX Exhaled Nitric Oxide Monitoring System, Aerocrine, Sweden) in 3 European and 2 US centers. Each child performed 3...... NO in 405 children was 9.7 ppb, and the upper 95% confidence limit was 25.2 ppb. FE NO increased significantly with age, and higher FE NO was seen in children with self-reported rhinitis/conjunctivitis or hay fever. The success rate was age-dependent and improved from 40% in the children 4 years old...

  10. Perception of depth distance of integral photography through the measurement of eye movement and subjective test

    Science.gov (United States)

    Yano, Sumio; Suzuki, Makoto; Park, Min-Chul

    2017-05-01

    We developed a measurement tool for binocular eye movement and examined the perception of depth distance in integral photography images, which is a type of three dimensional image, using the tool we developed. Furthermore, we evaluated the perception of the depth distance in integral photography images by the subjective test, and we considered the perception results of the depth distance, which were these two experimental results. Additionally, we examined the perception of the depth distance in the real objects, and compared with the results in the case of integral photography images and real objects.

  11. Personality dimensions measured by the Temperament and Character Inventory (TCI) in subjects with social phobia.

    Science.gov (United States)

    Marteinsdottir, Ina; Tillfors, Maria; Furmark, Tomas; Anderberg, Ulla Maria; Ekselius, Lisa

    2003-01-01

    The present study investigated personality dimensions by means of the Temperament and Character Inventory (TCI) in subjects with social phobia with or without a co-existing avoidant personality disorder. Thirty-one individuals with social phobia were recruited through advertisement and diagnosed with the Structured Clinical Interview for DSM-IV I and II psychiatric disorders. Comorbid Axis I psychiatric disorders were diagnosed in 29% of the cases. Co-occurring personality disorders were present in 55.8% of the cases, and avoidant personality disorder in 48.4%. The social phobia subjects, as compared to healthy controls of the same age, scored significantly higher in the TCI dimension measuring Harm avoidance but significantly lower in Persistence, Self-directedness, Cooperativeness and Self-transcendence. Presence of avoidant personality disorders in the social phobia subjects was associated with significantly higher Harm avoidance, particularly on the subscale Shyness with strangers. In conclusion, individuals with social phobia were characterized by high comorbidity of avoidant personality disorder and deviations in TCI personality dimensions. Enhanced Harm avoidance was the most prominent personality trait. The observed deviations in TCI dimensions were primarily related to the social phobia itself and not to the presence of concurrent personality disorders.

  12. Hemodynamic alterations measured with phase-contrast MRI in a giant cerebral aneurysm treated with a flow-diverting stent

    Directory of Open Access Journals (Sweden)

    Matthew Ethan MacDonald, PhD

    2015-01-01

    Full Text Available Many risk factors have been proposed in the development of the cerebral aneurysms. Hemodynamics including blood velocity, volume flow rate (VFR, and intravascular pressure are thought to be prognostic indicators of aneurysm development. We hypothesize that treatment of cerebral aneurysm using a flow-diverting stent will bring these hemodynamic parameters closer to those observed on the contralateral side. In the current study, a patient with a giant cerebral aneurysm was studied pre- and postoperatively using phase contrast MRI (PC-MRI to measure the hemodynamic changes resulting from the deployment of a flow-diverting stent. PC-MRI was used to calculate intravascular pressure, which was compared to more invasive endovascular catheter-derived measurements. After stent placement, the measured VFRs in vessels of the treated hemisphere approached those measured on the contralateral side, and flow symmetry changed from a laterality index of -0.153 to 0.116 in the middle cerebral artery. Pressure estimates derived from the PC-MRI velocity data had an average difference of 6.1% as compared to invasive catheter transducer measurements. PC-MRI can measure the hemodynamic parameters with the same accuracy as invasive methods pre- and postoperatively.

  13. Therapeutic misconception in research subjects: development and validation of a measure.

    Science.gov (United States)

    Appelbaum, Paul S; Anatchkova, Milena; Albert, Karen; Dunn, Laura B; Lidz, Charles W

    2012-12-01

    Therapeutic misconception (TM), which occurs when research subjects fail to appreciate the distinction between the imperatives of clinical research and ordinary treatment, may undercut the process of obtaining meaningful consent to clinical research participation. Previous studies have found that TM is widespread, but progress in addressing TM has been stymied by the absence of a validated method for assessing its presence. The goal of this study was to develop and validate a theoretically grounded measure of TM, assess its diagnostic accuracy, and test previous findings regarding TM's prevalence. A total of 220 participants were recruited from clinical trials at four academic medical centers in the United States. Participants completed a 28-item Likert-type questionnaire to assess the presence of beliefs associated with TM, and a semistructured TM interview designed to elicit their perceptions of the nature of the clinical trial in which they were participating. Data from the questionnaires were subjected to factor analysis, and items with poor factor loadings were excluded. This resulted in a 10-item scale, with three strongly correlated factors and excellent internal consistency; the fit indices of the model across 10 training sets were consistent with the original results, suggesting a stable factor solution. The scale was validated against the TM interview, with significantly higher scores among subjects coded as displaying evidence of TM. Receiver operating curve (ROC) analysis based on a 10-fold internal cross-validation yielded area under the ROC (AUC) = 0.682 for any evidence of TM. When sensitivity (0.72) and specificity (0.61) were both optimized, positive predictive value was 0.65 and negative predictive value was 0.68, with a positive likelihood ratio of 1.89 and a negative likelihood ratio of 0.47. In all, 50.5% (n = 101) of the participants manifested evidence of TM on the TM interview, a somewhat lower rate than in most previous studies. The

  14. Network, anatomical, and non-imaging measures for the prediction of ADHD diagnosis in individual subjects

    Directory of Open Access Journals (Sweden)

    Jason W Bohland

    2012-12-01

    Full Text Available Brain imaging methods have long held promise as diagnostic aids for neuropsychiatric conditions with complex behavioral phenotypes such as Attention-Deficit/Hyperactivity Disorder. This promise has largely been unrealized, at least partly due to the heterogeneity of clinical populations and the small sample size of many studies. A large, multi-center dataset provided by the ADHD-200 Consortium affords new opportunities to test methods for individual diagnosis based on MRI-observable structural brain attributes and functional interactions observable from resting state fMRI. In this study, we systematically calculated a large set of standard and new quantitative markers from individual subject datasets. These features (>12,000 per subject consisted of local anatomical attributes such as cortical thickness and structure volumes and both local and global resting state network measures. Three methods were used to compute graphs representing interdependencies between activations in different brain areas, and a full set of network features was derived from each. Of these, features derived from the inverse of the time series covariance matrix, under an L1-norm regularization penalty, proved most powerful. Anatomical and network feature sets were used individually, and combined with non-imaging phenotypic features from each subject. Machine learning algorithms were used to rank attributes, and performance was assessed under cross-validation and on a separate test set of 168 subjects for a variety of feature set combinations. While non-imaging features gave highest performance in cross-validation, the addition of imaging features in sufficient numbers led to improved generalization to new data. Stratification by gender also proved to be a fruitful strategy to improve classifier performance. We describe the overall approach used, compare the predictive power of different classes of features, and describe the most impactful features in relation to the

  15. Empirical Analysis of the Subjective Impressions and Objective Measures of Domain Scientists’ Analytical Judgment Using Visualizations

    Energy Technology Data Exchange (ETDEWEB)

    Dasgupta, Aritra; Burrows, Susannah M.; Han, Kyungsik; Rasch, Philip J.

    2017-04-15

    Scientists working in a particular domain often adhere to conventional data analysis and presentation methods and this leads to familiarity with these methods over time. But does high familiarity always lead to better analytical judgment? This question is especially relevant when visualizations are used in scientific tasks, as there can be discrepancies between visualization best practices and domain conventions. However, there is little empirical evidence of the relationships between scientists’ subjective impressions about familiar and unfamiliar visualizations and objective measures of their effect on scientific judgment. To address this gap and to study these factors, we focus on the climate science domain, specifically on visualizations used for comparison of model performance. We present a comprehensive user study with 47 climate scientists where we explored the following factors: i) relationships between scientists’ familiarity, their perceived levels of com- fort, confidence, accuracy, and objective measures of accuracy, and ii) relationships among domain experience, visualization familiarity, and post-study preference.

  16. Measurement of dynamic ocular surface temperature in healthy subjects using a new thermography device.

    Science.gov (United States)

    Klamann, Matthias K J; Maier, Anna-Karina B; Gonnermann, Johannes; Klein, Julian P; Pleyer, Uwe

    2012-08-01

    To investigate the routine use and applicability of a new ocular thermography device (TG 1000; Tomey Corp, Nagoya, Japan) in healthy individuals. Sixty eyes of 30 healthy subjects were included in this prospective study. Intraobserver reproducibility was tested with an ocular surface-oriented infrared radiation thermographic device in a non-contact manner. Using a standard examination protocol, the ocular surface temperature was assessed by dynamic thermal imaging over a time period of 10 s. The procedure was repeated three times during a single session by one examiner. Intraclass correlation coefficients (ICC) were calculated. Ocular surface temperature measurements were highly reproducible. The mean ocular surface temperature was 34.02°C ± 0.22. The ICC was 0.947%, 0.949%, and 0.955% for minimum, maximum, and mean temperatures, respectively. Ocular surface temperature measurements made using the Tomey TG 1000 in healthy subjects showed excellent intraobserver reproducibility. This novel non-invasive technique offers new options for increased understanding of the physiology of the ocular surface.

  17. A Novel Noninvasive Method for Measuring Fatigability of the Quadriceps Muscle in Noncooperating Healthy Subjects

    Directory of Open Access Journals (Sweden)

    Jesper B. Poulsen

    2015-01-01

    Full Text Available Background. Critical illness is associated with muscle weakness leading to long-term functional limitations. Objectives. To assess the reliability of a novel method for evaluating fatigability of the quadriceps muscle in noncooperating healthy subjects. Methods. On two occasions, separated by seven days, nonvoluntary isometric contractions (twitch and tetanic of the quadriceps femoris muscle evoked by transcutaneous electrical muscle stimulation were recorded in twelve healthy adults. For tetanic contractions, the Fatigue Index (ratio of peak torque values and the slope of the regression line of peak torque values were primary outcome measures. For twitch contractions, maximum peak torque and rise time were calculated. Relative (intraclass correlation, ICC3.1 and absolute (standard error of measurement, SEM reliability were assessed and minimum detectable change was calculated using a 95% confidence interval (MDC95%. Results. The Fatigue Index (ICC3.1, 0.84; MDC95%, 0.12 and the slope of the regression line (ICC3.1, 0.99; MDC95%, 0.03 showed substantial relative and absolute reliability during the first 15 and 30 contractions, respectively. Conclusion. This method for assessing fatigability of the quadriceps muscle produces reliable results in healthy subjects and may provide valuable data on quantitative changes in muscle working capacity and treatment effects in patients who are incapable of producing voluntary muscle contractions.

  18. Age-related different relationships between ectopic adipose tissues and measures of central obesity in sedentary subjects

    National Research Council Canada - National Science Library

    Guglielmi, Valeria; Maresca, Luciano; D'Adamo, Monica; Di Roma, Mauro; Lanzillo, Chiara; Federici, Massimo; Lauro, Davide; Preziosi, Paolo; Bellia, Alfonso; Sbraccia, Paolo

    2014-01-01

    ... (SAT) were simultaneously measured by Magnetic Resonance Imaging (MRI) and related to waist circumference measurements and age in 32 sedentary subjects without cardiovascular disease (18 men; 14 women; mean age 48.5 ± 14 years...

  19. Measurement of Drug Craving in Persian Speaking Subjects; a Review on Current Experiences and Future Perspectives

    Directory of Open Access Journals (Sweden)

    Masoomeh Maarefvand

    2012-09-01

    Full Text Available Background: Drug craving is considered as one of the main cores of drug dependency and addiction. Multidimensionality of drug craving, its cultural-bounded features and its intra individual rapidly changing nature makes it difficult to be measured. Nowadays, regarding different psychometric approaches, there are various instruments available for measurement of different aspects of drug craving but mainly for Latin-based languages in North America and European countries. High prevalence and special conditions, and unique subcultures in substance abuse and addiction in many countries, like Iran, make the design of culturally validated instruments for drug craving assessment priority. Materials and Methods: Comprehensive review on drug craving measurement instruments for Persian speaking subjects have been performed by searching in databases (ELSEVIER, Science Direct and Scientific Information Database (SID and investigating of related documents on regional experiences. Results: In this article seven main categories of drug craving instruments have been reviewed focusing on validated versions in Persian language including: self-reports, reinforcement “proxies”, drug self administration, psycho physiological responding, neurobiological responding, cognitive processing and expressive methods. Conclusion: Reviewing on weak and strength points of each instrument group and national and regional experiences shows that designing and validating a new series of ecologically-validated instruments for multidimensional measurement of drug craving in different addiction subcultures should be prioritized to cover current methodological gaps in substance abuse studies in Iran.

  20. High spatiotemporal resolution measurement of regional lung air volumes from 2D phase contrast x-ray images

    Energy Technology Data Exchange (ETDEWEB)

    Leong, Andrew F. T.; Islam, M. Sirajul; Kitchen, Marcus J. [School of Physics, Monash University, Victoria 3800 (Australia); Fouras, Andreas [Division of Biological Engineering, Monash University, Victoria 3800 (Australia); Wallace, Megan J.; Hooper, Stuart B. [Ritchie Centre and Department of Obstetrics and Gynaecology, Monash Institute of Medical Research, Monash University, Victoria 3168 (Australia)

    2013-04-15

    Purpose: Described herein is a new technique for measuring regional lung air volumes from two-dimensional propagation-based phase contrast x-ray (PBI) images at very high spatial and temporal resolution. Phase contrast dramatically increases lung visibility and the outlined volumetric reconstruction technique quantifies dynamic changes in respiratory function. These methods can be used for assessing pulmonary disease and injury and for optimizing mechanical ventilation techniques for preterm infants using animal models. Methods: The volumetric reconstruction combines the algorithms of temporal subtraction and single image phase retrieval (SIPR) to isolate the image of the lungs from the thoracic cage in order to measure regional lung air volumes. The SIPR algorithm was used to recover the change in projected thickness of the lungs on a pixel-by-pixel basis (pixel dimensions {approx}16.2 {mu}m). The technique has been validated using numerical simulation and compared results of measuring regional lung air volumes with and without the use of temporal subtraction for removing the thoracic cage. To test this approach, a series of PBI images of newborn rabbit pups mechanically ventilated at different frequencies was employed. Results: Regional lung air volumes measured from PBI images of newborn rabbit pups showed on average an improvement of at least 20% in 16% of pixels within the lungs in comparison to that measured without the use of temporal subtraction. The majority of pixels that showed an improvement was found to be in regions occupied by bone. Applying the volumetric technique to sequences of PBI images of newborn rabbit pups, it is shown that lung aeration at birth can be highly heterogeneous. Conclusions: This paper presents an image segmentation technique based on temporal subtraction that has successfully been used to isolate the lungs from PBI chest images, allowing the change in lung air volume to be measured over regions as small as the pixel size. Using

  1. Objective and subjective measures of the quality of managed care in nursing homes.

    Science.gov (United States)

    Schnelle, J F; Ouslander, J G; Buchanan, J; Zellman, G; Farley, D; Hirsch, S H; Reuben, D B

    1999-04-01

    The number of nursing home (NH) residents enrolled in managed care plans (HMO) will increase, and there is concern that the quality of their medical care may be compromised by cost-containment pressures. In this study, we evaluated the medical care of residents enrolled in 3 health maintenance organizations (HMO) that developed specific long-term care programs. To compare the medical care received by NH residents enrolled in HMO and Fee-for-Service (FFS) plans with both objective process of care and consumer perception (subjective) measures. To describe the relationship between the objective and subjective measures. Number of primary care visits per month; process of medical care for 2 geriatric tracer conditions (falls, fevers); family and residents' perceptions of the adequacy of sickness episode management; and the frequency of primary provider visits. Quasi-experimental. HMO residents received more timely and appropriate responses to falls and fevers than did FFS residents. HMO residents also received more frequent routine visits by a primary care provider team consisting of a physician and nurse practitioner. Consumer perceptions of quality did not differ between the HMO and FFS groups. Families within both groups were significantly more positive than were residents about the frequency of visits by both physicians and nurse practitioners. Within the HMO group, both families and residents were more positive about the frequency of nurse practitioner visits than were physician visits even when the frequency of visits by the 2 providers were similar. Although the medical care received by HMO residents was better on most objective process measures than that received by FFS residents, consumer perceptions of care did not detect those differences. NH residents and families have different perceptions about the adequacy of visits by physicians and nurse practitioners, and both families and residents appear to have different expectations concerning how often they want

  2. Internal Lymphedema Correlates with Subjective and Objective Measures of Dysphagia in Head and Neck Cancer Patients.

    Science.gov (United States)

    Jackson, Leanne K; Ridner, Sheila H; Deng, Jie; Bartow, Carmin; Mannion, Kyle; Niermann, Ken; Gilbert, Jill; Dietrich, Mary S; Cmelak, Anthony J; Murphy, Barbara A

    2016-09-01

    Tumor/treatment-related internal lymphedema (IL) and/or external lymphedema (EL) are associated with functional deficits and increased symptom burden in head and neck cancer patients (HNCP). Previously, we noted association between EL/IL and patient-reported dysphagia using the Vanderbilt Head and Neck Symptom Survey (VHNSS) version 1.0. To determine the relationship between IL/EL and subjective and objective measures of swallowing function. Eighty-one HNCP completed: (1) VHNSS version 2.0, including 13 swallowing/nutrition-related questions grouped into three clusters: swallow solids (ss), swallow liquids (sl), and nutrition(nt); (2) physical assessment of EL using Foldi scale; (3) endoscopic assessment of IL using Patterson scale (n = 56); and (4) modified barium swallow study rated by dysphagia outcome and severity scale (DOSS) and in conjunction with a swallow evaluation by National Outcomes Measurement System (NOMS). Examinations were performed at varied time points to assess lymphedema spectrum, from baseline (n = 15, 18.1%) to 18 months post-therapy (n = 20, 24.1%). VHNSS swallow/nutrition items scores correlated with NOMS/DOSS ratings (p nutrition scores correlated with maximum grade of swelling for any single structure on Patterson scale: ss (0.43; p = 0.001); sl (0.38; p = 0.004); nt (0.41; p = 0.002). IL of aryepiglottic/pharyngoepiglottic folds, epiglottis, and pyriform sinus were most strongly correlated with VHNSS and NOMS ratings. NOMS/DOSS ratings correlated with EL (> = -0.34; p nutrition items and EL ( 0.20). IL correlated with subjective and objective measures of swallow dysfunction. Longitudinal analysis of trajectory and impact of IL/EL on dysphagia is ongoing.

  3. An open source, 3D printed preclinical MRI phantom for repeated measures of contrast agents and reference standards.

    Science.gov (United States)

    Cox, B L; Ludwig, K D; Adamson, E B; Eliceiri, K W; Fain, S B

    2018-03-01

    In medical imaging, clinicians, researchers and technicians have begun to use 3D printing to create specialized phantoms to replace commercial ones due to their customizable and iterative nature. Presented here is the design of a 3D printed open source, reusable magnetic resonance imaging (MRI) phantom, capable of flood-filling, with removable samples for measurements of contrast agent solutions and reference standards, and for use in evaluating acquisition techniques and image reconstruction performance. The phantom was designed using SolidWorks, a computer-aided design software package. The phantom consists of custom and off-the-shelf parts and incorporates an air hole and Luer Lock system to aid in flood filling, a marker for orientation of samples in the filled mode and bolt and tube holes for assembly. The cost of construction for all materials is under $90. All design files are open-source and available for download. To demonstrate utility, B 0 field mapping was performed using a series of gadolinium concentrations in both the unfilled and flood-filled mode. An excellent linear agreement (R 2 >0.998) was observed between measured relaxation rates (R 1 /R 2 ) and gadolinium concentration. The phantom provides a reliable setup to test data acquisition and reconstruction methods and verify physical alignment in alternative nuclei MRI techniques (e.g. carbon-13 and fluorine-19 MRI). A cost-effective, open-source MRI phantom design for repeated quantitative measurement of contrast agents and reference standards in preclinical research is presented. Specifically, the work is an example of how the emerging technology of 3D printing improves flexibility and access for custom phantom design.

  4. Relationship between intracranial pressure and phase contrast cine MRI derived measures of intracranial pulsations in idiopathic normal pressure hydrocephalus.

    Science.gov (United States)

    Jaeger, Matthias; Khoo, Angela K; Conforti, David A; Cuganesan, Ramesh

    2016-11-01

    Phase contrast cine MRI with determination of pulsatile aqueductal cerebrospinal fluid (CSF) stroke volume and flow velocity has been suggested to assess intracranial pulsations in idiopathic normal pressure hydrocephalus (iNPH). We aimed to compare this non-invasive measure of pulsations to intracranial pressure (ICP) pulse wave amplitude from continuous ICP monitoring. We hypothesised that a significant correlation between these two markers of intracranial pulsations exists. Fifteen patients with suspected iNPH had continuous computerised ICP monitoring with calculation of mean ICP pulse wave amplitude (MWA) from time-domain analysis. MRI measured CSF aqueductal stroke volume and peak flow velocity. Mean MWA was 5.4mmHg (range 2.3-12.4mmHg). Mean CSF stroke volume and peak flow velocity were 65μl (range 3-195μl) and 9.31cm/s (range 1.68-15.0cm/s), respectively. No significant correlation between the invasive and non-invasive measures of pulsations existed (Spearman r=-0.30 and r=-0.27, respectively; p>0.05). We observed marked intra-individual fluctuation of MWA during continuous ICP monitoring of an average of 6.0mmHg (range 2.8-12.2mmHg). The results suggest a complex interplay between measures of pulsations derived from snapshot MRI measurements and continuous computerised ICP measurements, as no significant relationship existed in our data. Further study is needed to better understand the temporal profile of CSF MRI flow studies, as substantial variation in MWA over the course of several hours of ICP monitoring is common, suggesting that these physiologic fluctuations might obscure MRI snapshot measures of intracranial pulsations. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Evaluation of higher brain function by MRI. Flow measurement in the superior sagittal sinus using phase contrast method

    Energy Technology Data Exchange (ETDEWEB)

    Ono, Mototsugu [Yamada Red Cross Hospital, Misono, Mie (Japan)

    1997-01-01

    To assess the higher brain function, flow measurement in the superior sagittal sinus (SSS) was performed noninvasively using a phase contrast MRI in 76 patients with suspicious of impaired higher brain function including dementias (senile dementia of Alzheimer type; SDAT and multi-infarct dementia; MID), strokes, and others. Thirty-one normal controls were consisted of 18 healthy volunteers and 13 patients with tension headache whose higher brain function was proved be normal. Mean flow velocity was measured in the distal portion of the SSS adjoining to the occipital lobes and was multiplied by cross-sectional area of the SSS at the measuring point to obtain mean flow volume. For intellectual index, cross-cultural cognitive examination (CCCE) was applied to all cases excluding volunteers. Normal value of SSS flow volume measured by MRI was 6.92{+-}0.66 ml/s. Significant differences in both SSS flow and CCCE score from normal controls were found in SDAT group, MID group, and non-dementia group. No substantial differences between SDAT group and MID group were noted in both CCCE score and SSS flow. In normal controls, there was no correlation between SSS flow and age, whereas, significant inverse correlation of SSS flow with age was found in all cases. Between CCCE score and SSS flow, there were nearly linear relationships in all cases, SDAT group, MID group, and non-dementia group. Significant but relatively poor correlation was found in normals. (K.H.)

  6. Vocal efficiency measurements in subjects with vocal polyps and nodules: a preliminary report.

    Science.gov (United States)

    Jiang, Jack; Stern, Jennifer; Chen, Hui-Jun; Solomon, Nancy Pearl

    2004-04-01

    Vocal efficiency is a quantitative measure of the ability of the larynx to convert subglottal power to acoustic power. On the basis of the scant previous literature and clinical intuition, we tested the hypothesis that vocal efficiency, as an indicator of the functional status of the larynx, is abnormally reduced in persons with vocal nodules and polyps. Because the most difficult aspect of obtaining measures of vocal efficiency has been the determination of subglottal pressure, we applied a noninvasive airflow interruption technique for this purpose. Subjects with normal voices (n = 22), vocal polyps (n = 14), and vocal nodules (n = 16) phonated at different intensities into a mask connected by way of piping to a flow meter, a pressure transducer, and an acoustic microphone. Inflation of a balloon-type valve located within the piping provided interruption of phonation. The intraoral pressure plateau occurring during flow interruption was used to estimate subglottal pressure. Subglottal power and acoustic power were determined, and their quotient provided a measure of vocal efficiency. The vocal efficiency in the normal subjects averaged 1.15 x 10(-5) at 70 dB, 3.17 x 10(-5) at 75 dB, 7.52 x 10(-5) at 80 dB, and 1.41 x 10(-4) at 85 dB. The vocal efficiency in the patients with vocal polyps averaged 3.62 x 10(-6) at 70 dB, 8.34 x 10(-6) at 75 dB, 2.10 x 10(-5) at 80 dB, and 4.26 x 10(-5) at 85 dB. The vocal efficiency in the patients with vocal nodules averaged 4.32 x 10(-6) at 70 dB, 1.57 x 10(-5) at 75 dB, 4.26 x 10(-5) at 80 dB, and 8.34 x 10(-5) at 85 dB. As compared to the normal subjects, the patients with laryngeal polyps or vocal nodules had significantly reduced vocal efficiency. These results provide quantitative verification of the clinical impression of inefficient phonation in patients with mass lesions of the vocal folds.

  7. Peak velocity measurements in tortuous arteries with phase contrast magnetic resonance imaging: the effect of multidirectional velocity encoding.

    Science.gov (United States)

    Schubert, Tilman; Bieri, Oliver; Pansini, Michele; Stippich, Christoph; Santini, Francesco

    2014-04-01

    Blood flow velocity measurement with phase contrast magnetic resonance imaging (PC-MRI) is widely applied in clinical routine imaging. Usually, velocity and volumetric flow measurements are performed using unidirectional encoding of the through-plane velocity with a 2-dimensional (2D) acquisition. Single-slice acquisitions and measurements with unidirectional encoding, however, may lead to significant errors, especially in tortuous vessels, but might benefit from higher signal-to-noise ratios (SNRs). To evaluate the impact of volumetric acquisition and multidirectional velocity encoding, blood velocity measurements were performed at 3 locations in the distal internal carotid artery with a 3-dimensional, 3-directional time-resolved phase contrast (PC) sequence (4-dimensional [4D]) and a 2D acquisition with 3-directional (2D-3dir) and through-plane velocity encoding (2D-tp) derived from the same sequence. Twenty carotid arteries of 10 healthy volunteers (24-37 years) were evaluated. For each volunteer, 1 4D acquisition and 3 2D 3-directional PC measurements were placed according to a time-of-flight angiography. Unidirectionally encoded through-plane velocities were derived from the multidirectionally encoded 2D scan by discarding the in-plane components. Regions of interest were identified on the slab after postprocessing and visualization for the 4D data set as well as directly on the digital imaging and communications in medicine images for the 2D measurement. Blood flow velocity, volumetric flow, and SNRs were measured at carotid segments C4, C5, and C7 on both sides obtaining 20 values per vessel location. The quantities were tested for significant differences between each modality at all 3 locations with paired t tests. At the segments C5 and C7, the highest peak velocities (PVs) were measured with the 4D sequence, followed by 2D-3dir and 2D tp. The PV differences between the sequences were significant (P measured with 2D-tp. The mean PV value of the 4D sequence

  8. Flash Infrared Thermography Contrast Data Analysis Technique

    Science.gov (United States)

    Koshti, Ajay

    2014-01-01

    This paper provides information on an IR Contrast technique that involves extracting normalized contrast versus time evolutions from the flash thermography inspection infrared video data. The analysis calculates thermal measurement features from the contrast evolution. In addition, simulation of the contrast evolution is achieved through calibration on measured contrast evolutions from many flat-bottom holes in the subject material. The measurement features and the contrast simulation are used to evaluate flash thermography data in order to characterize delamination-like anomalies. The thermal measurement features relate to the anomaly characteristics. The contrast evolution simulation is matched to the measured contrast evolution over an anomaly to provide an assessment of the anomaly depth and width which correspond to the depth and diameter of the equivalent flat-bottom hole (EFBH) similar to that used as input to the simulation. A similar analysis, in terms of diameter and depth of an equivalent uniform gap (EUG) providing a best match with the measured contrast evolution, is also provided. An edge detection technique called the half-max is used to measure width and length of the anomaly. Results of the half-max width and the EFBH/EUG diameter are compared to evaluate the anomaly. The information provided here is geared towards explaining the IR Contrast technique. Results from a limited amount of validation data on reinforced carbon-carbon (RCC) hardware are included in this paper.

  9. Effect of respiratory pattern on automated clinical blood pressure measurement: an observational study with normotensive subjects.

    Science.gov (United States)

    Herakova, Natalia; Nwobodo, Nnenna Harmony Nzeribe; Wang, Ying; Chen, Fei; Zheng, Dingchang

    2017-01-01

    It has been reported that deep breathing could reduce blood pressures (BP) in general. It is also known that BP is decreased during inhalation and increased during exhalation. Therefore, the measured BPs could be potentially different during deep breathing with different lengths of inhalation and exhalation. This study aimed to quantitatively investigate the effect of different respiratory patterns on BPs. Forty healthy subjects (20 males and 20 females, aged from 18 to 60 years) were recruited. Systolic and diastolic BPs (SBP and DBP) were measured using a clinically validated automated BP device. There were two repeated measurement sessions for each subject. Within each session, eight BP measurements were performed, including 4 measurements during deep breathing with different respiratory patterns (Pattern 1: 4.5 s vs 4.5 s; Patter 2: 6 s vs 2 s; Pattern 3: 2 s vs 6 s; and Pattern 4: 1.5 s vs 1.5 s, respectively for the durations of inhalation and exhalation) and additional 4 measurements from 1 min after the four different respiratory patterns. At the beginning and end of the two repeated measurement sessions, there were two baseline BP measurements under resting condition. The key experimental results showed that overall automated SBP significantly decreased by 3.7 ± 5.7 mmHg, 3.9 ± 5.2 mmHg, 1.7 ± 5.9 mmHg and 3.3 ± 5.3 mmHg during deep breathing, respectively for Patterns 1, 2, 3 and 4 (all p Pattern 3). Similarly, the automated DBPs during deep breathing in pattern 1, 2 and 4 decreased by 3.7 ± 5.0 mmHg, 3.7 ± 4.9 mmHg and 4.6 ± 3.9 mmHg respectively (all p Pattern 3 with a decrease of 1.0 ± 4.3 mmHg, p = 0.14). Correspondingly, after deep breathing, automated BPs recovered back to normal with no significant difference in comparison with baseline BP (all p > 0.05, except for SBP in Pattern 4). In summary, this study has quantitatively demonstrated that the measured automated BPs decreased

  10. Effects of Background Music on Objective and Subjective Performance Measures in an Auditory BCI.

    Science.gov (United States)

    Zhou, Sijie; Allison, Brendan Z; Kübler, Andrea; Cichocki, Andrzej; Wang, Xingyu; Jin, Jing

    2016-01-01

    Several studies have explored brain computer interface (BCI) systems based on auditory stimuli, which could help patients with visual impairments. Usability and user satisfaction are important considerations in any BCI. Although background music can influence emotion and performance in other task environments, and many users may wish to listen to music while using a BCI, auditory, and other BCIs are typically studied without background music. Some work has explored the possibility of using polyphonic music in auditory BCI systems. However, this approach requires users with good musical skills, and has not been explored in online experiments. Our hypothesis was that an auditory BCI with background music would be preferred by subjects over a similar BCI without background music, without any difference in BCI performance. We introduce a simple paradigm (which does not require musical skill) using percussion instrument sound stimuli and background music, and evaluated it in both offline and online experiments. The result showed that subjects preferred the auditory BCI with background music. Different performance measures did not reveal any significant performance effect when comparing background music vs. no background. Since the addition of background music does not impair BCI performance but is preferred by users, auditory (and perhaps other) BCIs should consider including it. Our study also indicates that auditory BCIs can be effective even if the auditory channel is simultaneously otherwise engaged.

  11. Comparison between refraction measured by Spot Vision ScreeningTM and subjective clinical refractometry

    Directory of Open Access Journals (Sweden)

    Daniela Lima de Jesus

    2016-02-01

    Full Text Available OBJECTIVE: The purpose of this study was to evaluate the accuracy of Spot Vision ScreeningTM as an autorefractor by comparing refraction measurements to subjective clinical refractometry results in children and adult patients. METHODS: One-hundred and thirty-four eyes of 134 patients were submitted to refractometry by Spot and clinical refractometry under cycloplegia. Patients, students, physicians, staff and children of staff from the Hospital das Clínicas (School of Medicine, University of São Paulo aged 7-50 years without signs of ocular disease were examined. Only right-eye refraction data were analyzed. The findings were converted in magnitude vectors for analysis. RESULTS: The difference between Spot Vision ScreeningTM and subjective clinical refractometry expressed in spherical equivalents was +0.66±0.56 diopters (D, +0.16±0.27 D for the vector projected on the 90 axis and +0.02±0.15 D for the oblique vector. CONCLUSIONS: Despite the statistical significance of the difference between the two methods, we consider the difference non-relevant in a clinical setting, supporting the use of Spot Vision ScreeningTM as an ancillary method for estimating refraction.

  12. Comparison between refraction measured by Spot Vision Screening™ and subjective clinical refractometry.

    Science.gov (United States)

    de Jesus, Daniela Lima; Villela, Flávio Fernandes; Orlandin, Luis Fernando; Eiji, Fernando Naves; Dantas, Daniel Oliveira; Alves, Milton Ruiz

    2016-02-01

    The purpose of this study was to evaluate the accuracy of Spot Vision Screening™ as an autorefractor by comparing refraction measurements to subjective clinical refractometry results in children and adult patients. One-hundred and thirty-four eyes of 134 patients were submitted to refractometry by Spot and clinical refractometry under cycloplegia. Patients, students, physicians, staff and children of staff from the Hospital das Clínicas (School of Medicine, University of São Paulo) aged 7-50 years without signs of ocular disease were examined. Only right-eye refraction data were analyzed. The findings were converted in magnitude vectors for analysis. The difference between Spot Vision Screening™ and subjective clinical refractometry expressed in spherical equivalents was +0.66±0.56 diopters (D), +0.16±0.27 D for the vector projected on the 90 axis and +0.02±0.15 D for the oblique vector. Despite the statistical significance of the difference between the two methods, we consider the difference non-relevant in a clinical setting, supporting the use of Spot Vision Screening™ as an ancillary method for estimating refraction.

  13. Comparison between refraction measured by Spot Vision ScreeningTM and subjective clinical refractometry

    Science.gov (United States)

    de Jesus, Daniela Lima; Villela, Flávio Fernandes; Orlandin, Luis Fernando; Eiji, Fernando Naves; Dantas, Daniel Oliveira; Alves, Milton Ruiz

    2016-01-01

    OBJECTIVE: The purpose of this study was to evaluate the accuracy of Spot Vision ScreeningTM as an autorefractor by comparing refraction measurements to subjective clinical refractometry results in children and adult patients. METHODS: One-hundred and thirty-four eyes of 134 patients were submitted to refractometry by Spot and clinical refractometry under cycloplegia. Patients, students, physicians, staff and children of staff from the Hospital das Clínicas (School of Medicine, University of São Paulo) aged 7-50 years without signs of ocular disease were examined. Only right-eye refraction data were analyzed. The findings were converted in magnitude vectors for analysis. RESULTS: The difference between Spot Vision ScreeningTM and subjective clinical refractometry expressed in spherical equivalents was +0.66±0.56 diopters (D), +0.16±0.27 D for the vector projected on the 90 axis and +0.02±0.15 D for the oblique vector. CONCLUSIONS: Despite the statistical significance of the difference between the two methods, we consider the difference non-relevant in a clinical setting, supporting the use of Spot Vision ScreeningTM as an ancillary method for estimating refraction. PMID:26934234

  14. A Systematic Review on Existing Measures for the Subjective Assessment of Rehabilitation and Assistive Robot Devices

    Directory of Open Access Journals (Sweden)

    Yiannis Koumpouros

    2016-01-01

    Full Text Available The objective of the current study is to identify and classify outcome measures currently used for the assessment of rehabilitation or assistive robot devices. We conducted a systematic review of the literature using PubMed, MEDLINE, CIRRIE, and Scopus databases for studies that assessed rehabilitation or assistive robot devices from 1980 through January 2016. In all, 31 articles met all inclusion criteria. Tailor-made questionnaires were the most commonly used tool at 66.7%, while the great majority (93.9% of the studies used nonvalidated instruments. The study reveals the absence of a standard scale which makes it difficult to compare the results from different researchers. There is a great need, therefore, for a valid and reliable instrument to be available for use by the intended end users for the subjective assessment of robot devices. The study concludes by identifying two scales that have been validated in general assistive technology devices and could support the scope of subjective assessment in rehabilitation or assistive robots (however, with limited coverage and a new one called PYTHEIA, recently published. The latter intends to close the gap and help researchers and developers to evaluate, assess, and produce products that satisfy the real needs of the end users.

  15. Longitudinal measurement equivalence of subjective language brokering experiences scale in Mexican American adolescents.

    Science.gov (United States)

    Kim, Su Yeong; Hou, Yang; Shen, Yishan; Zhang, Minyu

    2017-04-01

    Language brokering occurs frequently in immigrant families and can have significant implications for the well-being of family members involved. The present study aimed to develop and validate a measure that can be used to assess multiple dimensions of subjective language brokering experiences among Mexican American adolescents. Participants were 557 adolescent language brokers (54.2% female, Mage.wave1 = 12.96, SD = .94) in Mexican American families. Using exploratory and confirmatory factor analyses, we were able to identify 7 reliable subscales of language brokering: linguistic benefits, socioemotional benefits, efficacy, positive parent-child relationships, parental dependence, negative feelings , and centrality . Tests of factorial invariance show that these subscales demonstrate, at minimum, partial strict invariance across time and across experiences of translating for mothers and fathers, and in most cases, also across adolescent gender, nativity, and translation frequency. Thus, in general, the means of the subscales and the relations among the subscales with other variables can be compared across these different occasions and groups. Tests of criterion-related validity demonstrated that these subscales correlated, concurrently and longitudinally, with parental warmth and hostility, parent-child alienation, adolescent family obligation, depressive symptoms, resilience, and life meaning. This reliable and valid subjective language brokering experiences scale will be helpful for gaining a better understanding of adolescents' language brokering experiences with their mothers and fathers, and how such experiences may influence their development. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  16. Effects of background music on objective and subjective performance measures in an auditory BCI

    Directory of Open Access Journals (Sweden)

    Sijie Zhou

    2016-10-01

    Full Text Available Several studies have explored brain computer interface (BCI systems based on auditory stimuli, which could help patients with visual impairments. Usability and user satisfaction are important considerations in any BCI. Although background music can influence emotion and performance in other task environments, and many users may wish to listen to music while using a BCI, auditory and other BCIs are typically studied without background music. Some work has explored the possibility of using polyphonic music in auditory BCI systems. However, this approach requires users with good musical skills, and has not been explored in online experiments. Our hypothesis was that an auditory BCI with background music would be preferred by subjects over a similar BCI without background music, without any difference in BCI performance. We introduce a simple paradigm (which does not require musical skill using percussion instrument sound stimuli and background music, and evaluated it in both offline and online experiments. The result showed that subjects preferred the auditory BCI with background music. Different performance measures did not reveal any significant performance effect when comparing background music vs. no background. Since the addition of background music does not impair BCI performance but is preferred by users, auditory (and perhaps other BCIs should consider including it. Our study also indicates that auditory BCIs can be effective even if the auditory channel is simultaneously otherwise engaged.

  17. A Systematic Review on Existing Measures for the Subjective Assessment of Rehabilitation and Assistive Robot Devices.

    Science.gov (United States)

    Koumpouros, Yiannis

    2016-01-01

    The objective of the current study is to identify and classify outcome measures currently used for the assessment of rehabilitation or assistive robot devices. We conducted a systematic review of the literature using PubMed, MEDLINE, CIRRIE, and Scopus databases for studies that assessed rehabilitation or assistive robot devices from 1980 through January 2016. In all, 31 articles met all inclusion criteria. Tailor-made questionnaires were the most commonly used tool at 66.7%, while the great majority (93.9%) of the studies used nonvalidated instruments. The study reveals the absence of a standard scale which makes it difficult to compare the results from different researchers. There is a great need, therefore, for a valid and reliable instrument to be available for use by the intended end users for the subjective assessment of robot devices. The study concludes by identifying two scales that have been validated in general assistive technology devices and could support the scope of subjective assessment in rehabilitation or assistive robots (however, with limited coverage) and a new one called PYTHEIA, recently published. The latter intends to close the gap and help researchers and developers to evaluate, assess, and produce products that satisfy the real needs of the end users.

  18. Pipelines subject to slow landslide movements: Structural modeling vs field measurement

    Energy Technology Data Exchange (ETDEWEB)

    Bruschi, R.; Glavina, S.; Spinazze, M.; Tomassini, D. [Snamprogetti S.p.A., Fano (Italy); Bonanni, S.; Cuscuna, S. [Snam S.p.A., Milan (Italy)

    1996-12-01

    In recent years finite element techniques have been increasingly used to investigate the behavior of buried pipelines subject to soil movements. The use of these tools provides a rational basis for the definition of minimum wall thickness requirements in landslide crossings. Furthermore the design of mitigation measures or monitoring systems which control the development of undesirable strains in the pipe wall over time, requires a detailed structural modeling. The scope of this paper is to discuss the use of dedicated structural modeling with relevant calibration to field measurements. The strain measurements used were regularly gathered from pipe sections, in two different sites over a period of time long enough to record changes of axial strain due to soil movement. Detailed structural modeling of pipeline layout in both sites and for operating conditions, is applied. Numerical simulations show the influence of the distribution of soil movement acting on the pipeline with regards to the state of strain which can be developed in certain locations. The role of soil nature and direction of relative movements in the definition of loads transferred to the pipeline, is also discussed.

  19. Limitations of subjective cognitive load measures in simulation-based procedural training.

    Science.gov (United States)

    Naismith, Laura M; Cheung, Jeffrey J H; Ringsted, Charlotte; Cavalcanti, Rodrigo B

    2015-08-01

    The effective implementation of cognitive load theory (CLT) to optimise the instructional design of simulation-based training requires sensitive and reliable measures of cognitive load. This mixed-methods study assessed relationships between commonly used measures of total cognitive load and the extent to which these measures reflected participants' experiences of cognitive load in simulation-based procedural skills training. Two groups of medical residents (n = 38) completed three questionnaires after participating in simulation-based procedural skills training sessions: the Paas Cognitive Load Scale; the NASA Task Load Index (TLX), and a cognitive load component (CLC) questionnaire we developed to assess total cognitive load as the sum of intrinsic load (how complex the task is), extraneous load (how the task is presented) and germane load (how the learner processes the task for learning). We calculated Pearson's correlation coefficients to assess agreement among these instruments. Group interviews explored residents' perceptions about how the simulation sessions contributed to their total cognitive load. Interviews were audio-recorded, transcribed and subjected to qualitative content analysis. Total cognitive load scores differed significantly according to the instrument used to assess them. In particular, there was poor agreement between the Paas Scale and the TLX. Quantitative and qualitative findings supported intrinsic cognitive load as synonymous with mental effort (Paas Scale), mental demand (TLX) and task difficulty and complexity (CLC questionnaire). Additional qualitative themes relating to extraneous and germane cognitive loads were not reflected in any of the questionnaires. The Paas Scale, TLX and CLC questionnaire appear to be interchangeable as measures of intrinsic cognitive load, but not of total cognitive load. A more complete understanding of the sources of extraneous and germane cognitive loads in simulation-based training contexts is

  20. In situ observation and measurement of composites subjected to extremely high temperature

    Science.gov (United States)

    Fang, Xufei; Yu, Helong; Zhang, Guobing; Su, Hengqiang; Tang, Hongxiang; Feng, Xue

    2014-03-01

    In this work, we develop an instrument to study the ablation and oxidation process of materials such as C/SiC (carbon fiber reinforced silicon carbide composites) and ultra-high temperature ceramic in extremely high temperature environment. The instrument is integrated with high speed cameras with filtering lens, infrared thermometers and water vapor generator for image capture, temperature measurement, and humid atmosphere, respectively. The ablation process and thermal shock as well as the temperature on both sides of the specimen can be in situ monitored. The results show clearly the dynamic ablation and liquid oxide flowing. In addition, we develop an algorithm for the post-processing of the captured images to obtain the deformation of the specimens, in order to better understand the behavior of the specimen subjected to high temperature.

  1. Distortion-Product Otoacoustic Emission Measured Below 300 Hz in Normal-Hearing Human Subjects

    DEFF Research Database (Denmark)

    Christensen, Anders Tornvig; Ordoñez Pizarro, Rodrigo Eduardo; Hammershøi, Dorte

    2017-01-01

    Physiological noise levels in the human ear canal often exceed naturally low levels of otoacoustic emissions (OAEs) near the threshold of hearing. Low-frequency noise, and electronic filtering to cope with it, has effectively limited the study of OAE to frequencies above about 500 Hz. Presently......, a custom-built low-frequency acoustic probe was put to use in 21 normal-hearing human subjects (of 34 recruited). Distortion-product otoacoustic emission (DPOAE) was measured in the enclosed ear canal volume as the response to two simultaneously presented tones with frequencies f1 and f2. The stimulus...... known from higher frequencies. Toward low frequencies, however, the bell broadens and the optimal ratio increases proportionally to the bandwidth of an auditory filter as defined by the equivalent rectangular bandwidth. The DPOAE phase rotates monotonously as a function of the stimulus ratio, and its...

  2. Measuring the degradation level of polymer films subjected to partial discharges

    Energy Technology Data Exchange (ETDEWEB)

    Bozzo, R.; Gemme, C.; Guastavino, F. [Univ. of Genoa (Italy). Electrical Engineering Dept.; Tiemblo, P. [Inst. de Ciencia y Tecnologia de Polimeros, Madrid (Spain)

    1996-12-31

    Polymer films have been subjected to partial discharge (PD) aging. It is shown that statistical quantities derived from partial discharges patterns can be related to test conditions, film characteristics and degradation level. PDs have been measured by means of a digital system. Several resulting PD patterns have been elaborated and about 50 derived and statistical quantities have been obtained for each pattern. The effects of the test conditions on the derived quantities has been studied with relevance to the following items: To recognize the kind of film under test; to correlate the value of quantities with the degradation level of the film (i.e., to focus at the quantities which change with time); to find a link between the quantities values and the test ambient conditions (i.e., relative humidity); to determine the influence of the film thickness; and to evidence the effect of the voltage level.

  3. Phase contrast imaging measurements of reversed shear Alfvén eigenmodes during sawteeth in Alcator C-Moda)

    Science.gov (United States)

    Edlund, E. M.; Porkolab, M.; Kramer, G. J.; Lin, L.; Lin, Y.; Wukitch, S. J.

    2009-05-01

    Reversed shear Alfvén eigenmodes (RSAEs) have been observed with the phase contrast imaging diagnostic and Mirnov coils during the sawtooth cycle in Alcator C-mod [M. Greenwald et al., Nucl. Fusion 45, S109 (2005)] plasmas with minority ion-cyclotron resonance heating. Both down-chirping RSAEs and up-chirping RSAEs have been observed during the sawtooth cycle. Experimental measurements of the spatial structure of the RSAEs are compared to theoretical models based on the code NOVA [C. Z. Cheng and M. S. Chance, J. Comput. Phys. 71, 124 (1987)] and used to derive constraints on the q profile. It is shown that the observed RSAEs can be understood by assuming a reversed shear q profile (up chirping) or a q profile with a local maximum (down chirping) with q ≈1.

  4. Human vestibular memory studied via measurement of the subjective horizontal during gondola centrifugation.

    Science.gov (United States)

    Tribukait, Arne

    2003-07-01

    Measurements of the subjective visual horizontal (SVH) were made in a large swing-out gondola centrifuge. Rotation of the centrifuge was anti-clockwise, as seen from above. Test subjects were seated upright in the gondola, facing forwards. In front of the subject, at a straight-ahead eye-level position, there was a narrow luminous line, which could be rotated, by remote control, about the visual axis. At gravitoinertial force levels of 1.1-1.3G the subjects were asked to indicate, by repeatedly setting the line in darkness, what they perceived as horizontal (the SVH). During gondola centrifugation, the head and body length axis is always parallel with the resultant gravitoinertial force vector (vectorial sum of earth gravity force and the centrifugal force) i.e., the horizontal plane of the head or body does not change with respect to the gravitoinertial horizontal. Hence, the otolith organs, as well as the somatosensory system, continually signal upright position. However, the swing-out of the gondola during acceleration of the centrifuge (25 degrees at 1.1G) is a roll (frontal plane) change-in-position stimulus to the vertical semicircular canals, thus creating an otolith-semicircular canal conflict. After acceleration of the centrifuge, the SVH was initially tilted up to 20 degrees to the right relative to the gravitoinertial horizontal. Since there was no roll-tilt stimulus to gravity receptors, this SVH tilt must be related to stimulation of the semicircular canals. However, it decayed much more slowly than any known effects of angular-velocity stimulation of the semicircular canals. The decay was bi-phasic with two time constants, the smaller in the region of 1-2 min, the other being too large to be reliably estimated on the basis of data collected during only 10 min. This persistence of the SVH tilt suggests a memory for angular changes in roll head position detected by the semicircular canals-a position-storage mechanism. Further, the SVH seems to be

  5. Observer Design for One-Sided Lipschitz Nonlinear Systems Subject to Measurement Delays

    Directory of Open Access Journals (Sweden)

    Sohaira Ahmad

    2015-01-01

    Full Text Available This paper presents a novel nonlinear observer-design approach to one-sided Lipschitz nonlinear systems in the presence of output delays. The crux of the approach is to overcome the practical consequences of time delays, encountered due to distant sensor position and time lag in measurement, for estimation of physical and engineering nonlinear system states. A Lyapunov-Krasovskii functional is employed, the time derivative of which is solved using Jensen’s inequality, one-sided Lipschitz condition, and quadratic inner-boundedness, and, accordingly, design conditions for delay-range-dependent nonlinear observer for delayed one-sided Lipschitz systems are derived. Further, novel solutions to the problems of delay-dependent observer synthesis of one-sided Lipschitz models and delay-range-dependent state estimation of linear and Lipschitz nonlinear systems are deduced from the present delay-range-dependent technique. An observer formulation methodology for retrieval of one-sided Lipschitz nonlinear-system states, which is robust against L2 norm-bounded perturbations, is devised. The resultant design conditions, in contrast to the conventional procedures, can be solved via less conservative linear matrix inequality- (LMI- based routines that succeed by virtue of additional LMI variables, meaningful transformations, and cone complementary linearization algorithm. Numerical examples are worked out to illustrate the effectiveness of the proposed observer-synthesis approach for delayed one-sided Lipschitz systems.

  6. Temporal and Physiologic Measurements of Deglutition in the Upright and Supine Position with Videofluoroscopy (VFS) in Healthy Subjects.

    Science.gov (United States)

    Su, H K; Khorsandi, A; Silberzweig, J; Kobren, A J; Urken, M L; Amin, M R; Branski, R C; Lazarus, C L

    2015-08-01

    Cross-sectional imaging has long been employed to examine swallowing in both the sagittal and axial planes. However, data regarding temporal swallow measures in the upright and supine positions are sparse, and none have employed the MBS impairment profile (MBSImP). We report temporal swallow measures, physiologic variables, and swallow safety of upright and supine swallowing in healthy subjects using videofluoroscopy (VFS). Twenty healthy subjects ages 21-40 underwent VFS study upright and supine. Subjects were viewed in the sagittal plane and swallowed 5 mL liquid and pudding barium. Oral transit time, pharyngeal delay time, pharyngeal response time, pharyngeal transit time, and total swallow duration were measured. Penetration/aspiration scores and 14 MBSImP variables were analyzed in both positions. All subjects completed swallows supine, although one aspirated on one liquid bolus. Temporal measures of swallowing were similar for pudding upright and supine. Pharyngeal phase swallow measures were longer for liquids in supine. MBSImP physiologic measures revealed a pharyngeal delay in both positions. Although Pen/Asp range was higher supine, more subjects penetrated upright. Temporal measures were increased for liquids in supine. Although Pen/Asp range was higher in supine, more subjects penetrated upright. These results provide support for cross-sectional supine imaging of swallowing for pudding, but perhaps not thin liquids for dysphagic patients. Slightly thicker liquids might prove reliable in supine without compromising swallow safety. Future research should examine swallow physiology in both positions in dysphagic and older healthy subjects.

  7. Screening for pulmonary arteriovenous malformations: contrast echocardiography versus pulse oximetry

    DEFF Research Database (Denmark)

    Oxhøj, H; Kjeldsen, A D; Nielsen, G

    2000-01-01

    echocardiography with intravenous injection of echo contrast was performed in all subjects. Outcome measures were oxygen saturation change >2% units on changing body position and echo contrast observed in the left-sided heart chambers. Positive contrast echocardiography indicating the presence of PAVM was found...

  8. Use of memory strategies among younger and older adults: Results from objective and subjective measures

    Directory of Open Access Journals (Sweden)

    Aline Teixeira Fabricio

    Full Text Available Abstract Memory plays a fundamental role in the identity of people and in human life, as it enables us to interpret our surroundings and make decisions. It is known that the aging process can be accompanied by cognitive decline in some memory sub systems. However, the use of memory strategies can help encoding and retrieval of new information. Objective: The aim of this study was to identify and compare, using objective and subjective measures, which recall strategies are used spontaneously by young and older adults. Methods: Twenty-six first-year college students, and thirty-three seniors enrolled at the Third Age University of the same campus, completed a visual memory test including 18 black and white pictures, memorized a short story, and completed an open question about memory strategies, a memory check list to indicate strategies used, and a memory self-efficacy scale. The Bousfield categorization measure was also calculated from the recall protocol. Results: Young adults demonstrated better performance than the older adults on the memory tasks, and were also more confident. Both groups reported using similar strategies. Conclusion: Young and older adults seem to tackle memory tasks in similar ways but young adults outperform seniors.

  9. Relationship between Voice Complaints and Subjective and Objective Measures of Vocal Function in Iranian Female Teachers.

    Science.gov (United States)

    Faham, Maryam; Jalilevand, Nahid; Torabinezhad, Farhad; Silverman, Erin Pearson; Ahmadi, Akram; Anaraki, Zahra Ghayoumi; Jafari, Narges

    2017-07-01

    Teachers are at high risk of developing voice problems because of the excessive vocal demands necessitated by their profession. Teachers' self-assessment of vocal complaints, combined with subjective and objective measures of voice, may enable better therapeutic decision-making. This investigation compared audio-perceptual assessment and acoustic variables in teachers with and without voice complaints. Ninety-nine teachers completed this cross-sectional study and were assigned to one of two groups: those "with voice complaint (VC)" and those "without voice complaint (W-VC)." Voice samples were collected during reading, counting, and vowel prolongation tasks. Teachers were also asked to document any voice symptoms they experienced. Voice samples were analyzed using Dr. Speech program (4th version; Tiger Ltd., USA), and labeled "normal" or "abnormal" according to the "grade" dimension "G" from GRBAS scale. Twenty-one teachers were assigned to the VC group based on self-assessment data. There were statistically significant differences between the two groups with regard to self-reported voice symptoms of hoarseness, breathiness, pitch breaks, and vocal fatigue (P Teachers with and without voice complaints differed in the incidence, but not type of voice symptoms. Teachers' voice complaints did not correspond to perceptual and acoustic measures. This suggests a potential unmet need for teachers to receive further education on voice disorders. Copyright © 2017 The Voice Foundation. All rights reserved.

  10. Impedance measures in analysis and characterization of multistable structures subjected to harmonic excitation

    Science.gov (United States)

    Harne, Ryan L.; Goodpaster, Benjamin A.

    2018-01-01

    Structural components susceptible to adverse, post-buckled dynamic behaviors have long challenged the success of applications requiring lightweight, slender curved structures, while researchers have begun to leverage such bistable systems in emerging applications for novel energy attenuation and shape-changing properties. To expedite development and deployment of these built-up platforms containing post-buckled constituents, efficient approaches are required to complement time-consuming full-field models in the prediction of the near- and far-from-equilibrium dynamics. This research meets the need by introducing a semi-analytical model framework to enable the characterization of steady-state responses in multi degree-of-freedom (DOF) and multistable structural systems subjected to harmonic excitation. In so doing, the pathway for assessing impedance measures is created here so as to identify how energy travels and returns within built-up multistable structures. Verified by simulations and qualitatively validated by experiments, the analysis is shown to accurately reproduce both near- and far-from-equilibrium responses including different classes of energetic snap-through dynamics that only exist in such multistable structures. A first look at the impedance measures of different dynamic regimes reveals a connection between damping in multistable structures and the sustainability of far-from-equilibrium oscillations.

  11. Measuring Mentalizing Ability: A Within-Subject Comparison between an Explicit and Implicit Version of a Ball Detection Task.

    Directory of Open Access Journals (Sweden)

    Annabel D Nijhof

    Full Text Available The concept of mentalizing has been widely studied, but almost exclusively through tasks with explicit instructions. Recent studies suggest that people also mentalize on a more implicit level. However, to our knowledge, no study to date has directly contrasted the effects of implicit and explicit mentalizing processes on an implicit dependent measure within-subjects. We implemented this by using two versions of an object detection task, differing only on secondary catch questions. We hypothesized that if explicit mentalizing relies on complementary processes beyond those underlying implicit mentalizing, this would be reflected in enhanced belief effects in the explicit version. Twenty-eight healthy adults watched movies in which, during the first phase, both they themselves and another agent formed a belief about the location of a ball, and although irrelevant, these beliefs could influence their ball detection reaction times in the second phase. After this response phase, there were occasional catch questions that were different for the explicit and implicit task version. Finally, self-report measures of autism spectrum disorder (ASD symptomatology were included, as the literature suggests that ASD is related to a specific deficit in implicit mentalizing. Both in the explicit and implicit version, belief conditions had a significant effect on reaction times, with responses being slower when neither the participant nor the other agent expected the ball to be present compared to all other conditions. Importantly, after the implicit version, participants reported no explicit mentalizing awareness. In our neurotypical sample, ASD symptoms were not found to correlate with either explicit or implicit mentalizing. In conclusion, the reaction time patterns in the explicit and implicit version of the task show strikingly similar effects of mentalizing, indicating that participants processed beliefs to the same extent regardless of whether they

  12. Measuring Mentalizing Ability: A Within-Subject Comparison between an Explicit and Implicit Version of a Ball Detection Task.

    Science.gov (United States)

    Nijhof, Annabel D; Brass, Marcel; Bardi, Lara; Wiersema, Jan R

    2016-01-01

    The concept of mentalizing has been widely studied, but almost exclusively through tasks with explicit instructions. Recent studies suggest that people also mentalize on a more implicit level. However, to our knowledge, no study to date has directly contrasted the effects of implicit and explicit mentalizing processes on an implicit dependent measure within-subjects. We implemented this by using two versions of an object detection task, differing only on secondary catch questions. We hypothesized that if explicit mentalizing relies on complementary processes beyond those underlying implicit mentalizing, this would be reflected in enhanced belief effects in the explicit version. Twenty-eight healthy adults watched movies in which, during the first phase, both they themselves and another agent formed a belief about the location of a ball, and although irrelevant, these beliefs could influence their ball detection reaction times in the second phase. After this response phase, there were occasional catch questions that were different for the explicit and implicit task version. Finally, self-report measures of autism spectrum disorder (ASD) symptomatology were included, as the literature suggests that ASD is related to a specific deficit in implicit mentalizing. Both in the explicit and implicit version, belief conditions had a significant effect on reaction times, with responses being slower when neither the participant nor the other agent expected the ball to be present compared to all other conditions. Importantly, after the implicit version, participants reported no explicit mentalizing awareness. In our neurotypical sample, ASD symptoms were not found to correlate with either explicit or implicit mentalizing. In conclusion, the reaction time patterns in the explicit and implicit version of the task show strikingly similar effects of mentalizing, indicating that participants processed beliefs to the same extent regardless of whether they mentalized explicitly or

  13. Normative data of cortical excitability measurements obtained by transcranial magnetic stimulation in healthy subjects.

    Science.gov (United States)

    Cueva, Ana Sofia; Galhardoni, Ricardo; Cury, Rubens Gisbert; Parravano, Daniella Cardoso; Correa, Guilherme; Araujo, Haniel; Cecilio, Sofia Barros; Raicher, Irina; Toledo, Diego; Silva, Valquíria; Marcolin, Marco Antonio; Teixeira, Manoel Jacobsen; Ciampi de Andrade, Daniel

    2016-02-01

    The assessment of cortical excitability (CE) measurements has been increasingly used in neuropsychiatric research. However, there is scant information on the normative values of these measurements, as well as the possible effect of hemisphere laterality, gender and age on these variables. To obtain normative data for CE measurements by transcranial magnetic stimulation, to assess inter-/intra-investigator variability and the influence of sex, age and oral contraception use. A sample of 216 healthy volunteers matched according to age and gender was evaluated. Bilateral rest motor thresholds, motor evoked potentials (MEP), intracortical inhibition and facilitation were measured in the first dorsal interosseous muscle area representation of the primary motor cortex with a circular transcranial magnetic stimulation coil delivering biphasic pulses. Normative data were obtained for 200 participants (in a 1:1 male:female ratio) in a balanced proportion between five age groups (18-30; 31-40; 41-50; 51-60; >60 years). Inter/intra-investigator variability was assessed in 20 healthy volunteers in two sessions performed within a 30-minute interval. Measurements were also performed in a subgroup of 16 healthy female volunteers, using oral contraception and during the menstrual phase. Age had a dichotomous effect on CE measurements, providing significantly different normative data for subjects 50 years old, with smaller MEP's and intracortical inhibition in older individuals. There were no differences between genders or between left and right hemispheres. Also, CE parameters did not significantly differ with use of contraceptive treatment compared to the menstrual phase of the cycle. The inter-/intra-investigator reliability assessment showed some variability that may not be clinically significant. Age had a non-linear effect on CE. There were non-significant differences between genders, hemispheres or with use of oral contraceptives. There was good inter

  14. Across-subject calibration of an instrumented glove to measure hand movement for clinical purposes.

    Science.gov (United States)

    Gracia-Ibáñez, Verónica; Vergara, Margarita; Buffi, James H; Murray, Wendy M; Sancho-Bru, Joaquín L

    2017-05-01

    Motion capture of all degrees of freedom of the hand collected during performance of daily living activities remains challenging. Instrumented gloves are an attractive option because of their higher ease of use. However, subject-specific calibration of gloves is lengthy and has limitations for individuals with disabilities. Here, a calibration procedure is presented, consisting in the recording of just a simple hand position so as to allow capture of the kinematics of 16 hand joints during daily life activities even in case of severe injured hands. 'across-subject gains' were obtained by averaging the gains obtained from a detailed subject-specific calibration involving 44 registrations that was repeated three times on multiple days to 6 subjects. In additional 4 subjects, joint angles that resulted from applying the 'across-subject calibration' or the subject-specific calibration were compared. Global errors associated with the 'across-subject calibration' relative to the detailed, subject-specific protocol were small (bias: 0.49°; precision: 4.45°) and comparable to those that resulted from repeating the detailed protocol with the same subject on multiple days (0.36°; 3.50°). Furthermore, in one subject, performance of the 'across-subject calibration' was directly compared to another fast calibration method, expressed relative to a videogrammetric protocol as a gold-standard, yielding better results.

  15. Measurement of Rat Brain Tumor Kinetics Using an Intravascular MR Contrast Agent and DCE-MRI Nested Model Selection

    Science.gov (United States)

    Chwang, Wilson B.; Jain, Rajan; Bagher-Ebadian, Hassan; Nejad-Davarani, Siamak P.; Iskander, A.S.M.; VanSlooten, Ashley; Schultz, Lonni; Arbab, Ali S.; Ewing, James R.

    2015-01-01

    Purpose Using dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) in a rat glioma model, and nested model selection (NMS), to compare estimates of the pharmacokinetic parameters vp, Ktrans, and ve for two different contrast agents (CAs)—gadofosveset, which reversibly binds to human serum albumin, and gadopentetate dimeglumine, which does not. Materials and Methods DCE-MRI studies were performed on nine Fisher 344 rats inoculated intracerebrally with 9L gliosarcoma cells using both gadofosveset and gadopentetate. The parameters vp, Ktrans, and ve were estimated using NMS. Results Ktrans estimates using gadofosveset, compared to gadopentetate, differed in their means (gadofosveset 0.025 ± 0.008 min−1 vs. gadopentetate 0.046 ± 0.011 min−1; P = 0.0039). This difference notwithstanding, the intraclass correlation coefficient (ICC) for the two estimates of Ktrans showed nearly perfect linear dependence (ICC = 0.8479 by Pearson’s r). Other estimates, ve (gadofosveset 22.7 ± 4.7% vs. gadopentetate 23.6 ± 5.6%; P = 0.4258) and vp (gadofosveset 1.5 ± 0.5% vs. gadopentetate 1.6 ± 0.4%; P = 0.25), were not different in their means between the two CAs, and there was almost perfect agreement for ve (ICC = 0.8798) and substantial agreement for vp (ICC = 0.7981) between the two CAs. Conclusion Estimates of Ktrans were statistically different using gadofosveset and gadopentetate, whereas ve and vp were similar with two CAs. NMS produced robust estimates of pharmacokinetic parameters using DCE-MRI that show promise as important measures of tumor physiology and microenvironment. PMID:24421265

  16. Semi-automated primary tumor volume measurements by dynamic contrast-enhanced MRI in patients with head and neck cancer.

    Science.gov (United States)

    Lodder, Wouter L; Gilhuijs, Kenneth G A; Lange, Charlotte A H; Pameijer, Frank A; Balm, Alfons J M; van den Brekel, Michiel W M

    2013-04-01

    Tumor volume is a significant prognostic factor in the treatment of malignant head and neck tumors. Unfortunately, it is not routinely measured because of the workload involved. Twenty-one patients, between 2009 and 2010, were studied. Dynamic contrast-enhanced MRI (DCE-MRI) at 3.0T was performed. A workstation previously developed for semi-automated segmentation of breast cancers on DCE-MRI was used to segment the head and neck cancers. The Pearson correlation analysis was used to assess the agreement between volumetric measurements and the manually derived gross tumor volume (GTV). In 90.5% of the patients (19 of 21) correlation could be made between DCE-MRI and the manually derived GTV. The Pearson correlation coefficient between the automatically derived tumor volume at DCE-MRI and the manually derived GTVs was R(2) = 0.95 (p < .001). Semi-automated tumor volumes on DCE-MRI were representative of those derived from the manually derived GTV (R(2) = 0.95; p < .001). Copyright © 2012 Wiley Periodicals, Inc.

  17. Measurement of liver and spleen interstitial volume in patients with systemic amyloid light-chain amyloidosis using equilibrium contrast CT.

    Science.gov (United States)

    Yeung, Jason; Sivarajan, S; Treibel, T A; Rosmini, S; Fontana, M; Gillmore, J D; Hawkins, P N; Punwani, S; Moon, J C; Taylor, S A; Bandula, S

    2017-11-01

    To investigate equilibrium contrast-enhanced CT (EQ-CT) measurement of extracellular volume fraction (ECV) in patients with systemic amyloid light-chain (AL) amyloidosis, testing the hypothesis that ECV becomes elevated in the liver and spleen and ECV correlates with other estimates of organ amyloid burden. 26 patients with AL amyloidosis underwent EQ-CT, and ECV was measured in the liver and spleen. Patients also underwent serum amyloid P (SAP) component scintigraphy with grading of liver and spleen involvement. Mann-Whitney U test was used to test for a difference between patients with amyloid deposition (SAP grade 1-3) and those without (SAP grade 0). Variation in ECV across SAP grades was assessed using the Kruskal-Wallis test and association between ECV and SAP grades with Spearman correlation. Mean ECV in the spleen and liver was significantly greater (p ECV increased with increasing amyloid burden, showing positive correlation with SAP grade in both the liver (r = 0.758) and spleen (r = 0.867). In patients with systemic AL amyloidosis, EQ-CT can demonstrate increased spleen and liver ECV, which is associated with amyloid disease burden.

  18. Subjective Sleep Complaints in Pediatric Depression: A Controlled Study and Comparison with EEG Measures of Sleep and Waking

    Science.gov (United States)

    Bertocci, Michele A.; Dahl, Ronald E.; Williamson, Douglas E.; Iosif, Ana-Maria; Birmaher, Boris; Axelson, David; Ryan, Neal D.

    2005-01-01

    Objective: Children with major depressive disorder (MDD) often complain of sleep disturbances; however, polysomnographic studies have failed to find objective evidence of these disturbances. This article examines subjective sleep reports of children with MDD and healthy controls focusing on comparing subjective and objective sleep measures.…

  19. [Objective and subjective measures of sleep of shift-working nurses].

    Science.gov (United States)

    Matsumoto, Mitsuhiro; Lee, Bumsuk; Tozato, Fusae; Gennai, Kazuko; Shiihara, Yasufumi

    2014-01-01

    To objectively evaluate sleep quality of shift-working nurses, we used an Actiwatch 2, a watch-like actigraphy device designed to measure sleep and wakefulness based on the amount of movement. Subjective sleep quality was also assessed using the St. Mary's Hospital Sleep Questionnaire. Nineteen shift-working nurses wore the Actiwatch 2 for 5 days. The monitoring began with 2 days of the morning shift, which were followed by a 16-hour night shift and a rest day. Sleep recordings were obtained four times: night sleep after the second morning shift ("sleep 1"), napping on the night shift ("nap 1"), daytime napping after the night shift ("nap 2") and night sleep after the night shift ("sleep 2"). Actiwatch 2 sleep measures include sleep onset latency, snooze time, sleep efficiency, and percent sleep. In addition, the perceived quality of sleep was obtained using five questions of the St. Mary's Hospital Sleep Questionnaire. Objective and subjective sleep quality were compared between different sleep/nap times: sleep 1 vs. sleep 2, and nap 1 vs. nap 2. Percent sleep of sleep 2 was higher than that of sleep 1. In almost all responses to the St. Mary's Hospital Sleep Questionnaire, the perceived quality of sleep on sleep 2 was better than those of sleep 1, and that of nap 2 was better than nap 1. A significant negative correlation was found between the perceived sleep quality of nap 2 and the characteristics of participants (age, number of children, and length of career). There were positive correlations between the perceived sleep quality of sleep and percent sleep, and between the perceived sleep quality of nap and sleep efficiency. Moreover, the perceived sleep quality of nap 2 tended to decrease in participants whose bedtime deviated from the mean value on morning shift days and the rest day. We found that perceived sleep quality is related to percent sleep, and that the perceived sleep quality of nap is related to sleep efficiency. The results suggest that improving

  20. Contrasting Complement Control, Temporal Adjunct Control and Controlled Verbal Gerund Subjects in ASD: The Role of Contextual Cues in Reference Assignment

    OpenAIRE

    Janke, Vikki; Perovic, Alexandra

    2017-01-01

    This study examines two complex syntactic dependencies (complement control and sentence-final temporal adjunct control) and one pragmatic dependency (controlled verbal gerund subjects) in children with ASD. Sixteen high-functioning (HFA) children (aged 6 to 16) with a diagnosis of autism and no language impairment, matched on age, gender and non-verbal MA to one TD control group, and on age, gender and verbal MA to another TD control group, undertook three picture-selection tasks. Task 1 meas...

  1. Contrasting complement control, temporal adjunct control and controlled verbal gerund subjects in ASD: The role of contextual cues in reference assignment

    OpenAIRE

    Janke, V.; Perovic, A.

    2017-01-01

    This study examines two complex syntactic dependencies (complement control and sentence-final temporal adjunct control) and one pragmatic dependency (controlled verbal gerund subjects) in children with ASD. Sixteen high-functioning (HFA) children (aged 6–16) with a diagnosis of autism and no language impairment, matched on age, gender and non-verbal MA to one TD control group, and on age, gender and verbal MA to another TD control group, undertook three picture-selection tasks....

  2. Evaluation of Density Corrections to Methane Fluxes Measured by Open-Path Eddy Covariance over Contrasting Landscapes

    Science.gov (United States)

    Chamberlain, Samuel D.; Verfaillie, Joseph; Eichelmann, Elke; Hemes, Kyle S.; Baldocchi, Dennis D.

    2017-06-01

    Corrections accounting for air density fluctuations due to heat and water vapour fluxes must be applied to the measurement of eddy-covariance fluxes when using open-path sensors. Experimental tests and ecosystem observations have demonstrated the important role density corrections play in accurately quantifying carbon dioxide (CO2) fluxes, but less attention has been paid to evaluating these corrections for methane (CH4) fluxes. We measured CH4 fluxes with open-path sensors over a suite of sites with contrasting CH4 emissions and energy partitioning, including a pavement airfield, two negligible-flux ecosystems (drained alfalfa and pasture), and two high-flux ecosystems (flooded wetland and rice). We found that density corrections successfully re-zeroed fluxes in negligible-flux sites; however, slight overcorrection was observed above pavement. The primary impact of density corrections varied over negligible- and high-flux ecosystems. For negligible-flux sites, corrections led to greater than 100% adjustment in daily budgets, while these adjustments were only 3-10% in high-flux ecosystems. The primary impact to high-flux ecosystems was a change in flux diel patterns, which may affect the evaluation of relationships between biophysical drivers and fluxes if correction bias exists. Additionally, accounting for density effects to high-frequency CH4 fluctuations led to large differences in observed CH4 flux cospectra above negligible-flux sites, demonstrating that similar adjustments should be made before interpreting CH4 cospectra for comparable ecosystems. These results give us confidence in CH4 fluxes measured by open-path sensors, and demonstrate that density corrections play an important role in adjusting flux budgets and diel patterns across a range of ecosystems.

  3. Evaluation of Density Corrections to Methane Fluxes Measured by Open-Path Eddy Covariance over Contrasting Landscapes

    Science.gov (United States)

    Chamberlain, Samuel D.; Verfaillie, Joseph; Eichelmann, Elke; Hemes, Kyle S.; Baldocchi, Dennis D.

    2017-11-01

    Corrections accounting for air density fluctuations due to heat and water vapour fluxes must be applied to the measurement of eddy-covariance fluxes when using open-path sensors. Experimental tests and ecosystem observations have demonstrated the important role density corrections play in accurately quantifying carbon dioxide (CO2) fluxes, but less attention has been paid to evaluating these corrections for methane (CH4) fluxes. We measured CH4 fluxes with open-path sensors over a suite of sites with contrasting CH4 emissions and energy partitioning, including a pavement airfield, two negligible-flux ecosystems (drained alfalfa and pasture), and two high-flux ecosystems (flooded wetland and rice). We found that density corrections successfully re-zeroed fluxes in negligible-flux sites; however, slight overcorrection was observed above pavement. The primary impact of density corrections varied over negligible- and high-flux ecosystems. For negligible-flux sites, corrections led to greater than 100% adjustment in daily budgets, while these adjustments were only 3-10% in high-flux ecosystems. The primary impact to high-flux ecosystems was a change in flux diel patterns, which may affect the evaluation of relationships between biophysical drivers and fluxes if correction bias exists. Additionally, accounting for density effects to high-frequency CH4 fluctuations led to large differences in observed CH4 flux cospectra above negligible-flux sites, demonstrating that similar adjustments should be made before interpreting CH4 cospectra for comparable ecosystems. These results give us confidence in CH4 fluxes measured by open-path sensors, and demonstrate that density corrections play an important role in adjusting flux budgets and diel patterns across a range of ecosystems.

  4. Longitudinal changes in ultrasound measurements: a parallel study in subjects with genetic disorders and healthy controls.

    Science.gov (United States)

    Halaba, Zenon; Pyrkosz, Antoni; Adamczyk, Piotr; Drozdzowska, Bogna; Pluskiewicz, Wojciech

    2006-03-01

    Disturbances in skeletal status in subjects with genetic disorder may increase their fracture risk. The aim of the study was longitudinal observation of phalangeal speed of sound changes across the bone over a period of 2 y in 24 patients (14 boys and 10 girls, mean age 9.63 +/- 1.8 y.) and 24 age-matched healthy controls (14 boys and 10 girls, mean age 9.65 +/- 1.71 y.). Weight and height did not differ between patients and controls at baseline and follow-up. Patients with the following disorders were evaluated: 7 with Down syndrome, 6 nonspecific mental retardations of unknown etiology, 5 Martin-Bell syndrome and 6 with other diseases. In patients and controls, no factors potentially influencing bone metabolism (except for genetic disorder) were present. Bone status was assessed by quantitative ultrasound at hand phalanges using DBM Sonic 1200 (IGEA, Carpi, Italy), which measures amplitude-dependent speed of sound (Ad-SoS [m/s]). At baseline, Ad-SoS and Z-score were significantly lower in patients than in controls (1892 +/- 51 m/s versus 1936 +/- 43 m/s, p Z-score increased significantly in patients (1892 +/- 51 m/s to 1934 +/- 48 m/s, p Z-Score were significantly lower in patients (p Z-score weight did not differ between patients and control, and height increased more in controls (13.2 +/- 2.8 cm versus 11.4 +/- 5.9 cm, p over a period of observation. In conclusion, despite comparable improvement in measured ultrasound parameter in patients and controls observed over a study duration, the difference between them remained stable.

  5. Temperature measurement and control system for transtibial prostheses: Single subject clinical evaluation.

    Science.gov (United States)

    Ghoseiri, Kamiar; Zheng, Yong Ping; Leung, Aaron K L; Rahgozar, Mehdi; Aminian, Gholamreza; Masoumi, Mehdi; Safari, Mohammad Reza

    2017-01-05

    The snug fit of a prosthetic socket over the residual limb can disturb thermal balance and put skin integrity in jeopardy by providing an unpleasant and infectious environment. The prototype of a temperature measurement and control (TM&C) system was previously introduced to resolve thermal problems related to prostheses. This study evaluates its clinical application in a setting with reversal, single subject design. The TM&C system was installed on a fabricated prosthetic socket of a man with unilateral transtibial amputation. Skin temperature of the residual limb without prosthesis at baseline and with prosthesis during rest and walking was evaluated. The thermal sense and thermal comfort of the participant were also evaluated. The results showed different skin temperature around the residual limb with a temperature decrease tendency from proximal to distal. The TM&C system decreased skin temperature rise after prosthesis wearing. The same situation occurred during walking, but the thermal power of the TM&C system was insufficient to overcome heat build-up in some regions of the residual limb. The participant reported no significant change of thermal sense and thermal comfort. Further investigations are warranted to examine thermography pattern of the residual limb, thermal sense, and thermal comfort in people with amputation.

  6. Measuring Numeracy in a Community College Context: Assessing the Reliability of the Subjective Numeracy Scale

    Directory of Open Access Journals (Sweden)

    Kate S. Wolfe

    2017-07-01

    Full Text Available In this paper, our goals were to assess the suitability of the Subjective Numeracy Scale (SNS, developed for health-care use, in a new context with predominantly minority students at a South Bronx community college and to identify any race/ ethnicity, gender, and ESL enrollment effects. The scale assesses perceptions of quantitative reasoning skills and preferences for data presentation. This scale was given to a convenience sample of students in behavioral sciences classes. Results show that the SNS scale was reliable with our sample using the full thirteen-question scale or the shorter eight-item version. Gender, race/ ethnicity, and English as a Second Language (ESL are related to perceptions of QR/QL. This study may help researchers see the SNS as a reliable instrument across samples and as a way to measure numeracy. The results of the multivariate analyses raise questions for future research about cultural differences for numerical presentation among these ethnic groups and our international student population.

  7. Thermoluminescent properties of Dy doped calcium borate based glass for dose measurement subjected to photon irradiation

    Directory of Open Access Journals (Sweden)

    Tajuddin H. A.

    2017-01-01

    Full Text Available This study presents the thermoluminescent (TL dosimetric properties of calcium borate glass with various dopant concentration of dysprosium (Dy. Calcium borate glass is a new potential material to be used in radiation measurement with absorption coefficient that is close to human bone. A series of glasses based on chemical equation xCaO-(100-x B2O3 system, x = 0.1, 0.2, 0.3, 0.4, 0.5 (0< x <100 % weight have been prepared by melt quenching method. The X-ray diffraction analysis of glass samples were carried out and the result showed a broad peak, which confirmed the amorphous nature of the glass. The 70B2O3-30CaO glass sample was found as the most stable among other glass samples studied. Present work focuses on 70B2O3-30CaO glass of (0.01-0.4 mol% Dy-doped in order to investigate the thermoluminescence (TL properties, in particular, dose-response and fading. The glass samples were irradiated to dose range of 0.5-4.0 Gy subjected to 6MV photon irradiations of LINAC Primus MLC 3339. TL response of 0.3 mol% Dy-doped 70B2O3-30CaO glass was found to produce highest response, with good linear dose- response relationship.

  8. Comparison of global cerebral blood flow measured by phase-contrast mapping MRI with (15) O-H2 O positron emission tomography.

    Science.gov (United States)

    Vestergaard, Mark Bitsch; Lindberg, Ulrich; Aachmann-Andersen, Niels Jacob; Lisbjerg, Kristian; Christensen, Søren Just; Rasmussen, Peter; Olsen, Niels Vidiendal; Law, Ian; Larsson, Henrik Bo Wiberg; Henriksen, Otto Mølby

    2017-03-01

    To compare mean global cerebral blood flow (CBF) measured by phase-contrast mapping magnetic resonance imaging (PCM MRI) and by (15) O-H2 O positron emission tomography (PET) in healthy subjects. PCM MRI is increasingly being used to measure mean global CBF, but has not been validated in vivo against an accepted reference technique. Same-day measurements of CBF by (15) O-H2 O PET and subsequently by PCM MRI were performed on 22 healthy young male volunteers. Global CBF by PET was determined by applying a one-tissue compartment model with measurement of the arterial input function. Flow was measured in the internal carotid and vertebral arteries by a noncardiac triggered PCM MRI sequence at 3T. The measured flow was normalized to total brain weight determined from a volume-segmented 3D T1 -weighted anatomical MR-scan. Mean CBF was 34.9 ± 3.4 mL/100 g/min measured by (15) O-H2 O PET and 57.0 ± 6.8 mL/100 g/min measured by PCM MRI. The measurements were highly correlated (P = 0.0008, R(2)  = 0.44), although values obtained by PCM MRI were higher compared to (15) O-H2 O PET (absolute and relative differences were 22.0 ± 5.2 mL/100 g/min and 63.4 ± 14.8%, respectively). This study confirms the use of PCM MRI for quantification of global CBF, but also that PCM MRI systematically yields higher values relative to (15) O-H2 O PET, probably related to methodological bias. 3 J. Magn. Reson. Imaging 2017;45:692-699. © 2016 The Authors Journal of Magnetic Resonance Imaging published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine.

  9. Phase-contrast MRI measurement of systolic cerebrospinal fluid peak velocity (CSFV(peak)) in the aqueduct of Sylvius: a noninvasive tool for measurement of cerebral capacity.

    Science.gov (United States)

    Kolbitsch, C; Schocke, M; Lorenz, I H; Kremser, C; Zschiegner, F; Pfeiffer, K P; Felber, S; Aichner, F; Hörmann, C; Benzer, A

    1999-06-01

    Cerebrospinal fluid (CSF) outflow to intra- and extracranial subarachnoid spaces caused by arterial inflow to the brain predominantly compensates systolic increases in cerebral blood volume. Phase-contrast magnetic resonance imaging is a new tool for noninvasive assessment of CSF displacement by measuring CSF peak velocity (CSFV(Peak)). The authors tested this new tool in an experimental human model of increased intracranial pressure and reduced cerebral capacity by means of continuous positive airway pressure (CPAP) breathing. The authors investigated systolic CSFV(Peak) in the aqueduct of Sylvius in 11 awake, normocapnic (end-tidal carbon dioxide [ET(CO2)] = 40 mmHg) volunteers without CPAP and at two different CPAP levels (6 and 12 cm H2O) by means of electroencephalography-gated phase-contrast magnetic resonance imaging. Administration of 6 cm H2O CPAP did not change systolic CSFV(Peak) (-4.9+/-2.8 cm/s vs. control: -5.1+/-2.7 cm/s), whereas 12 cm H2O CPAP significantly reduced systolic CSFV(Peak) (-4.0+/-1.8 cm/s vs. control: -5.1+/-2.7 cm/s; P aqueduct of Sylvius is a sensitive method for detecting even minor impairment of cerebral capacity caused by experimentally induced increases in intracranial pressure.

  10. Interactions of Subjective and Objective Measures of Fatigue Defined in the Context of Brain Control of Locomotion.

    Science.gov (United States)

    Holtzer, Roee; Yuan, Jennifer; Verghese, Joe; Mahoney, Jeannette R; Izzetoglu, Meltem; Wang, Cuiling

    2017-03-01

    Fatigue adversely impacts quality of life in old age. The relationship between subjective and objective measurements of fatigue, however, is poorly understood. We examined whether subjective fatigue moderated the expression of objective fatigue during locomotion. Associations between objective and subjective measures of fatigue were predicted to manifest only under dual-task conditions that maximized cognitive demands. Participants were 314 nondemented older adults (age = 76.8±6.7 years; % female = 56). Functional near-infrared spectroscopy was used to assess oxygenated hemoglobin (HbO2) levels during walking. A 4×14-foot Zeno electronic walkway was utilized to assess stride velocity (cm/s). Objective fatigue was operationalized as attenuation in HbO2 levels and decline in stride velocity (cm/s) during six continuous straight walks under single- (normal-walk) and dual-task (walk-while-talk) conditions. The Brief Fatigue Inventory assessed subjective fatigue. Worse subjective fatigue was associated with attenuated increase in HbO2 levels (estimate = 0.175; p .05) from normal-walk to walk-while-talk conditions. Objective fatigue did not manifest and was not associated with subjective fatigue during the course of normal-walk. Worse subjective fatigue was associated with attenuated HbO2 levels in the fourth (estimate = -0.178; p subjective and objective measurements of fatigue as defined in the context of attention-demanding locomotion.

  11. Comparison of vessel contrast measured with a scanning-beam digital x-ray system and an image intensifier/television system.

    Science.gov (United States)

    Speidel, M A; Wilfley, B P; Heanue, J A; Betts, T D; Van Lysel, M S

    2001-02-01

    Vessel contrast was measured in the fluoroscopic images produced by a scanning-beam digital x-ray (SBDX) system and an image intensifier/television (II/TV) based system. The SBDX system electronically scans a series of pencil x-ray beams across the patient, each of which is directed at a distant small-area detector array. The reduction in detected scatter achieved with this geometry was expected to provide an increase in image contrast. Vessel contrast was evaluated from images of a phantom containing iodinated tubes. The vessels were inserted into an acrylic stack to provide a patient-mimicking scattering medium. Vessel diameter ranged from 0.3 to 3.1 mm. Images were acquired at 100 kVp with the SBDX and II/TV systems and averaged to reduce x-ray noise. The II/TV system was operated in the 6-in. image intensifier mode with an anti-scatter grid. The increase in contrast in the SBDX images, expressed as a ratio of the measured SBDX and II/TV contrasts, ranged from 1.63 to 1.79 for individual vessels. This agreed well with a prediction of the contrast improvement ratio for this experiment, based on measurements of the scatter fraction, object-plane line spread functions, and consideration of the source spectrum and detector absorption properties. The predicted contrast improvement ratio for SBDX relative to II/TV images was 1.62 to 1.77.

  12. Automated prescription of an optimal imaging plane for measurement of cerebral blood flow by phase contrast magnetic resonance imaging.

    Science.gov (United States)

    Teng, Pang-yu; Bagci, Ahmet Murat; Alperin, Noam

    2011-09-01

    This study describes and evaluates a semiautomated method for prescribing an optimal imaging plane that is located as close as possible to the skull base, and is simultaneously nearly perpendicular to the four arteries leading blood to the brain [internal carotid arteries (ICAs) and vertebral arteries (VAs)]. Such a method will streamline and improve reliability of the measurement of total cerebral blood flow and intracranial pressure by velocity encoding phase-contrast magnetic resonance imaging. The method first extracts the vessels' centerline from a 2-D time-of-flight magnetic resonance angiogram of the neck by performing distance transformations. An anatomical marker, the V2 segment of the VAs, is then identified to guide the imaging plane to be as close and below the skull base. An imaging plane that is nearly perpendicular to the ICAs and V2 segment of VAs is then identified by minimizing a misalignment value, estimated by a weighted mean of the angles between the plane's normal and the vessel axes at the vessel-plane intersections. The performance of the semiautomated method was evaluated by comparing manually selected planes to those found semiautomatically in nine magnetic resonance angiogram datasets. The semiautomated method consistently outperformed manual prescription with a significantly smaller misalignment value, 8.6° versus 20.7° (P < 0.001), respectively, and significantly improved reproducibility.

  13. Contrast visual acuity with bifocal contact lenses.

    Science.gov (United States)

    Ueda, Kiichi; Inagaki, Yasuko

    2007-03-01

    To compare the quality of vision of a bifocal rigid gas-permeable contact lens versus a bifocal soft contact lens in subjects with presbyopia. Sixteen healthy presbyopic subjects with no ocular disease but experienced with contact lens wear were enrolled in the study. Subjects randomly wore both types of bifocal lenses for 30 minutes with a washout period of 30 minutes each in a crossover manner. The primary outcome measure was the difference in contrast visual acuity. Distance and near contrast visual acuities with the two bifocal lens types were measured in different lighting environments and at multiple contrast levels. After the measurement, subjects were asked to rate their subjective vision by using the four categories with both lens types throughout the study. At the end of the study, subjects were also asked which of the two lens types they preferred. Under photopic conditions, distance and near visual acuities decreased at the 25% and 10% contrast levels, respectively, in subjects wearing bifocal soft contact lenses (Pcontact lenses (P0.05), but bifocal rigid gas-permeable lenses were clearer than bifocal soft contact lenses for near vision (Pcontact lenses showed better visual performance than bifocal soft contact lenses did.

  14. Subjective and objective measures of adaptation and readaptation to night work on an oil rig in the North Sea.

    Science.gov (United States)

    Bjorvatn, Bjørn; Stangenes, Kristine; Oyane, Nicolas; Forberg, Knut; Lowden, Arne; Holsten, Fred; Akerstedt, Torbjørn

    2006-06-01

    To study the adaptation and readaptation processes to 1 week of night work (6:30 PM to 6:30 AM) followed by 1 week of day work (6:30 AM to 6:30 PM). Part of a randomized, placebo-controlled, crossover field study. Here, data from the placebo arm are presented. Oil rig in the North Sea. Work schedule: 2 weeks on a 12-hour shift, with the first week on the night shift and the second week on the day shift. Subjects complaining about problems with adjusting to shift work. Seventeen workers completed the study. N/A. Subjective and objective measures of sleepiness (Karolinska Sleepiness Scale and simple serial reaction time test) and sleep (diary and actigraphy). Both subjective and objective measures improved gradually during night work. The return to day work after 1 week on the night shift led to a clear increase in subjective sleepiness and worsening of sleep parameters. During the week on the day shift, sleepiness and sleep gradually improved, similar to the improvement seen during night work. The workers indicated that the day shift was worse than the night shift on some of the measures, e.g., sleep length was significantly longer during the night-shift period. This is one of few studies showing how shift workers in a real-life setting adjust to night work. Both subjective and objective sleepiness and subjective sleep improved across days. The effects were especially pronounced for the subjective data.

  15. Within-subject variation in BOLD-fMRI signal changes across repeated measurements: Quantification and implications for sample size

    NARCIS (Netherlands)

    Zandbelt, B.B.; Gladwin, T.E.; Raemaekers, M.; Buuren, M. van; Neggers, S.F.W.; Kahn, R.S.; Ramsey, N.F.; Vink, M.

    2008-01-01

    Functional magnetic resonance imaging (fMRI) can be used to detect experimental effects on brain activity across measurements. The success of such studies depends on the size of the experimental effect, the reliability of the measurements, and the number of subjects. Here, we report on the stability

  16. Inter-relationships between objective and subjective measures of the residential environment among urban African American women.

    Science.gov (United States)

    Sealy-Jefferson, Shawnita; Messer, Lynne; Slaughter-Acey, Jaime; Misra, Dawn P

    2017-03-01

    The inter-relationships between objective (census based) and subjective (resident reported) measures of the residential environment is understudied in African American (AA) populations. Using data from the Life Influences on Fetal Environments Study (2009-2011; n = 1387) of AA women, we quantified the area-level variation in subjective reports of residential healthy food availability, walkability, safety, and disorder that can be accounted for with an objective neighborhood disadvantage index (NDI). Two-level generalized linear models estimated associations between objective and subjective measures of the residential environment, accounting for individual-level covariates. In unconditional models, intraclass correlation coefficients for block-group variance in subjective reports ranged from 11% (healthy food availability) to 30% (safety). Models accounting for the NDI (vs. both NDI and individual-level covariates) accounted for more variance in healthy food availability (23% vs. 8%) and social disorder (40% vs. 38%). The NDI and individual-level variables accounted for 39% and 51% of the area-level variation in walkability and safety, respectively. Associations between subjective and objective measures of the residential environment were significant and in the expected direction. Future studies on neighborhood effects on health, especially among AAs, should include a wide range of residential environment measures, including subjective, objective, and spatial contextual variables. Copyright © 2016 Elsevier Inc. All rights reserved.

  17. Contrast Sensitivity After Penetrating Keratoplasty Using The Pelli ...

    African Journals Online (AJOL)

    Corneal transplant surgeons recognize the usefulness of contrast sensitivity measurements in assessment of subjective vision of a penetrating graft recipient especially in real world conditions different from the doctor's consulting room. A large number of contrast sensitivity measurements either use expensive television ...

  18. Contrast Materials

    Science.gov (United States)

    ... safe are contrast materials? Contrast materials are safe drugs; adverse reactions ranging from mild to severe do occur but ... the use of medications such as Beta blockers , NSAIDs , interleukin 2 having received a large amount of ...

  19. Measurement of urinary kidney injury molecule-1 as a predictive biomarker of contrast-induced acute kidney injury

    Directory of Open Access Journals (Sweden)

    Fadhil Jawad Al-Tu’ma

    2017-03-01

    Conclusion Urinary KIM-1 was not useful for predicting or detecting CIN. But urinary KIM-1 level may be useful as a biomarker for tubular damage following intravascular administration of contrast media, 24 h.

  20. Coffee versus Caffeine: Effects on Subjective and Behavioral Measures of Alertness

    Science.gov (United States)

    1991-04-12

    particular attention to the impulsivity subscale of the Eysenck Personality Inventory ( Eysenck & Eysenck , 1964). Impulsivity is a construct related to...and only significant in one of the experiments (Exp.3). In a similar study, Anderson & Revelle (1982) again gave subjects the Eysenck Personality...Inventory ( Eysenck & Eysenck , 1964) and divided them into high and low impulsive groups based on a median split. Baseline caffeine intake of subjects

  1. Pharmacokinetic changes induced by focused ultrasound in glioma-bearing rats as measured by dynamic contrast-enhanced MRI.

    Science.gov (United States)

    Yang, Feng-Yi; Ko, Chia-En; Huang, Sheng-Yao; Chung, I-Fang; Chen, Gin-Shin

    2014-01-01

    Focused ultrasound (FUS) combined with microbubbles has been shown to be a noninvasive and targeted drug delivery technique for brain tumor treatment. The purpose of this study was to measure the kinetics of Gadolinium diethylenetriamine pentaacetic acid (Gd-DTPA) in glioma-bearing rats in the presence of FUS-induced blood-brain barrier disruption (BBB-D) by magnetic resonance imaging (MRI). A total of ten glioma-bearing rats (9-12 weeks, 290-340 g) were used in this study. Using dynamic contrast-enhanced (DCE)-MRI, the spatial permeability of FUS-induced BBB-D was evaluated and the kinetic parameters were calculated by a general kinetic model (GKM). The results demonstrate that the mean Ktrans of the sonicated tumor (0.128±0.019 at 20 min and 0.103±0.023 at 24 h after sonication, respectively) was significantly higher than (2.46-fold at 20 min and 1.78-fold at 24 h) that of the contralateral (non-sonicated) tumor (0.052±0.019 at 20 min and 0.058±0.012 at 24 h after sonication, respectively). In addition, the transfer constant Ktrans in the sonicated tumor correlated strongly with tissue EB extravasation (R = 0.95), which suggests that DCE-MRI may reflect drug accumulation in the brain. Histological observations showed no macroscopic damage except for a few small erythrocyte extravasations. The current study demonstrates that DCE-MRI can monitor the dynamics of the FUS-induced BBB-D process and constitutes a useful tool for quantifying BBB permeability in tumors.

  2. Objective-subjective disparity in cancer-related cognitive impairment: does the use of change measures help reconcile the difference?

    Science.gov (United States)

    O'Farrell, Erin; Smith, Andra; Collins, Barbara

    2017-10-01

    Studies to date have found little correlation between subjective and objective measures of cognitive function in cancer patients, making it difficult to interpret the significance of their cognitive complaints. The purpose of this study was to determine if a stronger correlation would be obtained using measures of cognitive change rather than static scores. Sixty women with early stage breast cancer underwent repeated cognitive assessment over the course of chemotherapy with a neuropsychological test battery (objective measure) and with the FACT-Cog (subjective measure). Their results were compared to 60 healthy women matched on age and education and assessed at similar intervals. We used multilevel modeling, with FACT-Cog as the dependent measure and ordinary least squares slopes of a neuropsychological summary score as the independent variable, to evaluate the co-variation between the subjective and objective measures over time RESULTS: Measures of both objective and subjective cognitive function declined over the course of chemotherapy in the breast cancer patients but there was no significant relationship between them, even when using change measures. Change in objective cognitive function was not related to change in anxiety or fatigue scores but the decline in perceived cognitive function was associated with greater anxiety and fatigue. The discrepancy in objective and subjective measures of cognition in breast cancer patients cannot be accounted for in terms of a failure to use change measures. Although the results are negative, we contend that this is the more appropriate methodology for analyzing cancer-related changes in cognition. Copyright © 2016 John Wiley & Sons, Ltd.

  3. Do Subjective Measures Improve the Ability to Identify Limited Health Literacy in a Clinical Setting?

    Science.gov (United States)

    Goodman, Melody S; Griffey, Richard T; Carpenter, Christopher R; Blanchard, Melvin; Kaphingst, Kimberly A

    2015-01-01

    Existing health literacy assessments developed for research purposes have constraints that limit their utility for clinical practice, including time requirements and administration protocols. The Brief Health Literacy Screen (BHLS) consists of 3 self-administered Single-Item Literacy Screener (SILS) questions and obviates these clinical barriers. We assessed whether the addition of SILS items or the BHLS to patient demographics readily available in ambulatory clinical settings reaching underserved patients improves the ability to identify limited health literacy. We analyzed data from 2 cross-sectional convenience samples of patients from an urban academic emergency department (n = 425) and a primary care clinic (n = 486) in St. Louis, Missouri. Across samples, health literacy was assessed using the Rapid Estimate of Adult Literacy in Medicine-Revised (REALM-R), Newest Vital Sign (NVS), and the BHLS. Our analytic sample consisted of 911 adult patients, who were primarily female (62%), black (66%), and had at least a high school education (82%); 456 were randomly assigned to the estimation sample and 455 to the validation sample. The analysis showed that the best REALM-R estimation model contained age, sex, education, race, and 1 SILS item (difficulty understanding written information). In validation analysis this model had a sensitivity of 62%, specificity of 81%, a positive likelihood ratio (LR(+)) of 3.26, and a negative likelihood ratio (LR(-)) of 0.47; there was a 28% misclassification rate. The best NVS estimation model contained the BHLS, age, sex, education and race; this model had a sensitivity of 77%, specificity of 72%, LR(+) of 2.75, LR(-) of 0.32, and a misclassification rate of 25%. Findings suggest that the BHLS and SILS items improve the ability to identify patients with limited health literacy compared with demographic predictors alone. However, despite being easier to administer in clinical settings, subjective estimates of health literacy have

  4. Objective Versus Subjective Measures of Executive Functions: Predictors of Participation and Quality of Life in Parkinson Disease?

    Science.gov (United States)

    Vlagsma, Thialda T; Koerts, Janneke; Tucha, Oliver; Dijkstra, Hilde T; Duits, Annelien A; van Laar, Teus; Spikman, Jacoba M

    2017-11-01

    To determine whether objective (neuropsychological tests) and subjective measures (questionnaires) of executive functions (EFs) are associated in patients with Parkinson disease (PD), and to determine to what extent level of participation and quality of life (QoL) of patients with PD can be predicted by these measures of EFs. Correlational research design (case-control and prediction design). Departments of neuropsychology of 3 medical centers. A sample (N=136) of patients with PD (n=42) and their relatives, and controls without PD (n=94). Not applicable. A test battery measuring EFs. In addition, patients, their relatives, and controls completed the Dysexecutive Questionnaire, Brock Adaptive Functioning Questionnaire, and Barkley Deficits in Executive Functioning Scale - time management questionnaires measuring complaints about EFs. Participation and QoL were measured with the Impact on Participation and Autonomy scale and the Parkinson's Disease Questionnaire-39, respectively. Patients with PD showed impairments in EFs on objective tests and reported significantly more complaints about EFs than did controls without PD. No associations were found between patients' performances on objective and subjective measures of EFs. However, both objective and subjective measures predicted patients' level of participation. In addition, subjective measures of EFs predicted QoL in patients with PD. These findings show that objective and subjective measures of EFs are not interchangeable and that both approaches predict level of participation and QoL in patients with PD. However, within this context, sex needs to be taken into account. Copyright © 2017 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

  5. Energy cost of walking measurements in subjects with lower limb amputations: a comparison study between floor and treadmill test.

    Science.gov (United States)

    Traballesi, Marco; Porcacchia, Paolo; Averna, Tiziano; Brunelli, Stefano

    2008-01-01

    Measuring the energy cost of walking (ECW) is a valid way of assessing the walking efficiency of subjects who were prosthetic users following lower limb amputation. The aim of this study was to determine whether, in these subjects, treadmill and floor ECW measurements are comparable. We tested 24 subjects who had undergone unilateral lower limb amputations for vascular diseases as they walked at a self-selected comfortable speed on the floor and on a treadmill. The tests were conducted at the end of rehabilitative treatment to fit prosthesis. Eight subjects underwent transtibial and 16 transfemoral amputation. The measurements were taken with a portable gas analyzer. The self-selected comfortable speed on the treadmill was significantly lower than that on the floor, where the patients adopted the aid they normally used for walking; oxygen consumption was the same in the two tests. Therefore, for both transtibial and transfemoral patients, ECW was greater during walking on the treadmill. Steady-state heart rate did not differ in the two tests. The data show that the ECW values of the amputated subjects obtained on the treadmill at the end of rehabilitation did not correspond with those they obtained on the floor. The floor test is the one that may better reflect walking with prostheses and aids in everyday life, in subjects with dysvascular lower limb amputation, using the prosthesis for a short time.

  6. Orientational contrast sensitivity and chromatic contrast thresholds in multiple sclerosis.

    Science.gov (United States)

    Jackson, Timothy L; Ong, Gek L; Ripley, Lionel G

    2004-02-01

    To investigate abnormalities of orientational contrast sensitivity (CS) and chromatic contrast threshold (CCT) in multiple sclerosis (MS). Case control study. Nine subjects (mean age, 42 +/- 11 years; range, 20-62 years) with MS, an expanded disability status scale of 3 or less, and normal visual acuity (VA) (logarithm of the minimum angle of resolution [logMAR] VA less than.1) in the tested eye were age-matched with 20 controls. Achromatic CS and CCT were measured using static, computer-generated sinusoidal gratings displayed on a high-resolution monitor. The CS and CCT of each subject were determined using a randomized double-staircase reversal algorithm; CS was measured at five spatial frequencies with horizontal orientation and three with vertical orientation; CCT was measured along the red-green and tritan confusion axes. The sensitivity thresholds of subjects were examined in relation to the mean sensitivity of controls for each spatial frequency. Two subjects had loss of horizontal and vertical CS, and three had isolated vertical loss. When compared with the control mean, there were significant reductions in red-green (P =.016) and tritan (P =.016) discrimination thresholds. This study used a computerized psychophysical test designed to minimize many of the test errors associated with earlier studies. It provides confirmatory evidence that MS may be associated with a loss of orientational CS and color vision, in the absence of reduced VA.

  7. Evaluation of Subjective Measurement Systems with Focus on Workmanship Scratches and Characterization

    Energy Technology Data Exchange (ETDEWEB)

    Fitzgerald, Jesse

    2011-02-24

    The presence of workmanship defects at the Kansas City Plant (KCP) is not a new problem nor is it an easy one to remedy. The lack of well defined parameters, subjective evaluations, and operator dependency makes this problem difficult to analyze. At the time of project assignment, workmanship defects comprised approximately 50% of all non-conformance reports for internally produced products. Not all of these non-conformances result in product rejections, thus inferring that inconsistency in evaluations were present. The purpose of this study was to identify a method for evaluating an operator’s ability to properly characterize subjective defects. Since the scope of the project was limited to no funding, scratch depth was selected as the only criteria to evaluate. It was determined that the introduction of a reference standard coupled with a predefined gate-sorting technique approved by the customer can statistically improve an operators ability to perform subjective evaluations.

  8. Contrast-induced nephropathy

    Directory of Open Access Journals (Sweden)

    Ricardo A. García Hernández

    2016-06-01

    Full Text Available Contrast-induced nephropathy is an important complication associated with the use of contrast media. Favoring factors for the development of contrast-induced nephronpathy have been widely described, being diabetes mellitus and previous renal disease the greatest risk. The pathophysiology is a complex process where the medullary hypoxia represents the trigger element. Previous hydration and the use of low osmolality contrast are the most recommended measures to prevent its development.

  9. Multispectral measurement of contrast in tissue-mimicking phantoms in near-infrared spectral range of 650 to 1600 nm

    Science.gov (United States)

    Salo, Daniel; Zhang, Hairong; Kim, David M.; Berezin, Mikhail Y.

    2014-01-01

    Abstract. In order to identify the optimal imaging conditions for the highest spatial contrast in biological tissue, we explored the properties of a tissue-mimicking phantom as a function of the wavelengths in a broad range of near-infrared spectra (650 to 1600 nm). Our customized multispectral hardware, which featured a scanning transmission microscope and imaging spectrographs equipped with silicon and InGaAs charge-coupled diode array detectors, allowed for direct comparison of the Michelson contrast obtained from a phantom composed of a honeycomb grid, Intralipid, and India ink. The measured contrast depended on the size of the grid, luminance, and the wavelength of measurements. We demonstrated that at low thickness of the phantom, a reasonable contrast of the objects can be achieved at any wavelength between 700 and 1400 nm and between 1500 and 1600 nm. At larger thicknesses, such contrast can be achieved mostly between 1200 and 1350 nm. These results suggest that distinguishing biological features in deep tissue and developing contrast agents for in vivo may benefit from imaging in this spectral range. PMID:25104414

  10. Objective Versus Subjective Measurement of Stress and Social Support: Combat-Related Reactions.

    Science.gov (United States)

    Solomon, Zahava; And Others

    1987-01-01

    Studied combat intensity, social support, and related stress reactions among soldiers who fought in the 1982 Israeli-Lebanon War, comparing those who experienced combat stress reaction (N=382) and those who did not (N=344). Subjective indicators were found to be stronger predictors than were objective indicators. Combat stress reaction was clearly…

  11. Application of LaserBreath-001 for breath acetone measurement in subjects with diabetes mellitus

    Science.gov (United States)

    Wang, Zhennan; Sun, Meixiu; Chen, Zhuying; Zhao, Xiaomeng; Li, Yingxin; Wang, Chuji

    2016-11-01

    Breath acetone is a promising biomarker of diabetes mellitus. With an integrated standalone, on-site cavity ringdown breath acetone analyzer, LaserBreath-001, we tested breath samples from 23 type 1 diabetic (T1D) patients, 312 type 2 diabetic (T2D) patients, 52 healthy subjects. In the cross-sectional studies, the obtained breath acetone concentrations were higher in the diabetic subjects compared with those in the control group. No correlation between breath acetone and simultaneous BG was observed in the T1D, T2D, and healthy subjects. A moderate positive correlation between the mean individual breath acetone concentrations and the mean individual BG levels was observed in the 20 T1D patients without ketoacidosis. In a longitudinal study, the breath acetone concentrations in a T1D patient with ketoacidosis decreased significantly and remained stable during the 5-day hospitalization. The results from a relatively large number of subjects tested indicate that an elevated mean breath acetone concentration exists in diabetic patients in general. Although many physiological parameters affect breath acetone concentrations, fast (diabetic screening and management under a specifically controlled condition.

  12. Sex differences in subjective and actigraphic sleep measures: A population-based study of elderly persons

    NARCIS (Netherlands)

    Berg, J.F. van den; Miedema, H.M.E.; Tulen, J.H.M.; Hofman, A.; Neven, A.K.; Tiemeier, H.

    2009-01-01

    Study Objectives: To investigate and explain sex differences in subjective and actigraphic sleep parameters in community-dwelling elderly persons. Design: Cross-sectional study. Setting: The study was embedded in the Rotterdam Study, a population-based study. Participants: Nine hundred fifty-six

  13. Perception of a Japanese Vowel Length Contrast by Japanese and American English listeners: Behavioral and Electrophysiological Measures

    OpenAIRE

    Hisagi, Miwako; Shafer, Valerie L.; Strange, Winifred; Sussman, Elyse S.

    2010-01-01

    This study examined the role of automatic selective perceptual processes in native and non-native listeners' perception of a Japanese vowel length contrast (tado vs. taado), using multiple, natural-speech tokens of each category as stimuli in a “categorial oddball” design. Mismatch Negativity (MMN) was used to index discrimination of the temporally-cued vowel contrast by naïve adult American listeners and by a native Japanese-speaking control group in two experiments in which attention to the...

  14. [Measuring facial paralysis using the three-dimensional dynamic quantitative analysis system of facial motion: correlation with subjective grading systems].

    Science.gov (United States)

    Zhao, Y; Feng, G D; Wu, H Y; Zhuang, Y; Gao, Z Q

    2016-07-07

    The aim of this study was to measure the facial motion of patients with facial paralysis using a three-dimensional dynamic quantitative analysis system of facial motion (3D ASFM) and analyze its correlation with subjective grading systems. We included 30 healthy volunteers and 50 patients with unilateral facial paralysis. After placing landmarks on the faces, the facial motions of the patients were measured using the 3D ASFM. The regional symmetry ratios(SRs) and gross scores of different parameters were calculated. Then a comparison with four subjective grading systems(House-Brackmann, Sunnybrook, Facial Nerve Grading System 2.0, Fisch) was performed. The entire test could be completed within five minutes. The normal range of healthy volunteers were obtained, the gross score of which was 91.9±1.5. The SRs of the maximal moving distance(MMD) were most strongly correlated with regional subjective grading systems, followed by the SRs of the maximal moving velocity (MMV). The SRs of the maximal moving acceleration (MMA) were either poorly correlated or uncorrelated with the subjective grading systems. Moreover, the Spearman coefficients with four subjective grading systems were -0.630(House-Brackmann), -0.728(Facial Nerve Grading System 2.0), 0.697(Sunnybrook), and 0.617(Fisch)respectively(Pfacial paralysis. It not only overcomes the shortcomings of conventional subjective grading systems, but also correlates well with them.

  15. A comparative study of autokeratometric and Scheimpflug keratometric measurements of the anterior corneal surface: results for a single subject

    Directory of Open Access Journals (Sweden)

    S. Mathebula

    2007-01-01

    Full Text Available One purpose of the broader study was to determine whether keratometric measurements obtained with an autokeratometer (Nidek ARK-700 would be comparable with those measured using the Oculus Pentacam(model 70700. Ten healthy subjects without ocular abnormality, no previous or current contact lens wear or history of ocular surgery were recruited and at least 43 successive keratometric measurements were obtained for the right eye of each subject using both instruments, namely the autokeratometer and the Pentacam. This paper will concern itself with data from only one of the ten subjects involved, namely Subject 1. The corneal powers were analyzed using multivariate methods for analyzing dioptric power. Scatter plots and meridional profiles of skewness and kurtosis were used to compare the results for the two instruments. Mean dioptric powers in conventional and scientific notation were determined.The results for this subject indicated that there was a statistically significant difference between the autokeratometry and the Pentacam. Although the means  between the two instruments were found to be significantly different at a 95% level of confidence, there was minimal clinical difference between the means of the two instruments. That is, this preliminary investigation suggests that in normal eyes, clinically, keratometric results obtained by means of an autokeratometer and a Pentacam are reasonably similar and can be used interchangeably.

  16. Discriminating between absorption and scattering coefficients in optical characterisation measurements on gold nanoparticle based photoacoustic contrast agents

    NARCIS (Netherlands)

    Ungureanu, C.; Manohar, Srirang; van Leeuwen, Ton; Amelink, A.; Sterenborg, Henricus J.C.M.; Oraevsky, Alexander A.; Wang, Lihong V.

    2009-01-01

    Plasmon resonant nanoparticles such as gold nanoshells and gold nanorods can be tuned to possess sharp interaction peaks in the near-infrared wavelength regions. These have great importance as contrast agents in photoacoustic imaging and as photothermal agents for therapeutic applications due to

  17. A novel noninvasive method for measuring fatigability of the quadriceps muscle in noncooperating healthy subjects

    DEFF Research Database (Denmark)

    Poulsen, Jesper Brøndum; Rose, Martin Høyer; Møller, Kirsten

    2015-01-01

    days, nonvoluntary isometric contractions (twitch and tetanic) of the quadriceps femoris muscle evoked by transcutaneous electrical muscle stimulation were recorded in twelve healthy adults. For tetanic contractions, the Fatigue Index (ratio of peak torque values) and the slope of the regression line......Background. Critical illness is associated with muscle weakness leading to long-term functional limitations. Objectives. To assess the reliability of a novel method for evaluating fatigability of the quadriceps muscle in noncooperating healthy subjects. Methods. On two occasions, separated by seven...... fatigability of the quadriceps muscle produces reliable results in healthy subjects and may provide valuable data on quantitative changes in muscle working capacity and treatment effects in patients who are incapable of producing voluntary muscle contractions....

  18. Measurement of effective alveolar carbon dioxide tension during spontaneous breathing in normal subjects and patients with chronic airways obstruction.

    Science.gov (United States)

    Jordanoglou, J; Koulouris, N; Kyroussis, D; Rapakoulias, P; Vassalos, P; Madianos, J

    1995-03-01

    The measurement of effective alveolar carbon dioxide tension (PA-CO2eff) is still a matter of debate. It has, however, become common practice to use arterial instead of alveolar CO2 tension for computing alveolar oxygen tension (PAO2) and physiological dead space, not only in normal subjects but also in patients. The purpose of this study was to estimate alveolar CO2 tension during spontaneous breathing with a new bedside technique which is simple and non-invasive, and to compare these values with arterial CO2 tension measured in normal subjects and patients with chronic airways obstruction. The subjects breathed quietly through the equipment assembly (mouthpiece, monitoring ring, Fleisch transducer head) connected to a pneumotachograph and a fast response infrared CO2 analyser. The method is a computerised calculation of the volume weighted effective alveolar CO2 tension obtained from the simultaneously recorded expiratory flow and CO2 concentration versus time curves. An arterial blood sample was taken to measure PaCO2 for comparison during the study. The results showed a mean difference (PACO2eff-PaCO2) of -0.205 kPa in 20 normal subjects and -0.460 kPa in 46 patients. The 95% confidence interval of the bias was -0.029 to -0.379 kPa in normal subjects and -0.213 to -0.707 kPa in patients. The limits of agreement between PACO2eff and PaCO2 were 0.526 to -0.935 in normal subjects and 1.170 to -2.088 in patients. The volume weighted effective alveolar PCO2 in normal subjects and patients with chronic airways obstruction is lower than the arterial PCO2 and is recommended as a better estimate in the classical equations for estimating dead space and intrapulmonary shunt.

  19. Changes after voice therapy in objective and subjective voice measurements of pediatric patients with vocal nodules.

    Science.gov (United States)

    Tezcaner, Ciler Zahide; Karatayli Ozgursoy, Selmin; Ozgursoy, Selmin Karatayli; Sati, Isil; Dursun, Gursel

    2009-12-01

    The aim of this study was to analyze the efficiency of the voice therapy in children with vocal nodules by using the acoustic analysis and subjective assessment. Thirty-nine patients with vocal fold nodules, aged between 7 and 14, were included in the study. Each subject had voice therapy led by an experienced voice therapist once a week. All diagnostic and follow-up workouts were performed before the voice therapy and after the third or the sixth month. Transoral and/or transnasal videostroboscopic examination and acoustic analysis were achieved using multi-dimensional voice program (MDVP) and subjective analysis with GRBAS scale. As for the perceptual assessment, the difference was significant for four parameters out of five. A significant improvement was found in the acoustic analysis parameters of jitter, shimmer, and noise-to-harmonic ratio. The voice therapy which was planned according to patients' needs, age, compliance and response to therapy had positive effects on pediatric patients with vocal nodules. Acoustic analysis and GRBAS may be used successfully in the follow-up of pediatric vocal nodule treatment.

  20. No correlation between joint position sense and force sense for measuring ankle proprioception in subjects with healthy and functional ankle instability.

    Science.gov (United States)

    Kim, Chang-Yong; Choi, Jong-Duk; Kim, Hyeong-Dong

    2014-11-01

    In general, ankle proprioception is most often evaluated by assessing joint position sense and force sense. However, in contrast to observational studies of joint position sense and force sense, no studies have examined the correlations between joint position sense and force sense. Therefore, the objective of this study was to investigate the correlations between joint position sense and force sense in subjects with healthy and functional ankle instability. Of the sixty nine subjects enrolled in the cross-sectional laboratory study, 35 had functional ankle instability and 34 were healthy subjects. Angle reproduction and force matching methods were used to quantify joint position sense and force sense of the ankle proprioception. These methods were also measured by using a flexible twin axis electrogoniometer and linear force, respectively. Three trials were performed at each angle and force. And then, absolute errors were calculated. Significant differences between the functional ankle instability and healthy group were found for absolute errors of plantar flexion, dorsiflexion, inversion, and eversion (P0.05). These findings suggest that it could be explained for deficits of ankle proprioception when angle reproduction and force matching tests to quantify joint position sense and force sense were applied and presented at the same time, not individually. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. Measuring Cognitive Load during Simulation-Based Psychomotor Skills Training: Sensitivity of Secondary-Task Performance and Subjective Ratings

    Science.gov (United States)

    Haji, Faizal A.; Khan, Rabia; Regehr, Glenn; Drake, James; de Ribaupierre, Sandrine; Dubrowski, Adam

    2015-01-01

    As interest in applying cognitive load theory (CLT) to the study and design of pedagogic and technological approaches in healthcare simulation grows, suitable measures of cognitive load (CL) are needed. Here, we report a two-phased study investigating the sensitivity of subjective ratings of mental effort (SRME) and secondary-task performance…

  2. The Beck depression inventory as a measure of subjective well-being : A cross-national study

    NARCIS (Netherlands)

    van Hemert, D.A.; van de Vijver, F.J.R.; Poortinga, Y.H.

    2002-01-01

    The present study examined the question whether the Beck Depression Inventory (BDI), which is one of the most widely used instruments to assess depression, can be used to measure differences in subjective well-being at national level. In order to establish the meaning of depression scores at country

  3. Sonographic measurements of low-echoic synovial area in the dorsal aspect of metatarsophalangeal joints in healthy subjects.

    Science.gov (United States)

    Hiraga, Masao; Ikeda, Kei; Shigeta, Koichiro; Sato, Akito; Yoshitama, Tamami; Hara, Ryota; Tanaka, Yasuhito

    2015-05-01

    Assessment of synovitis in the metatarsophalangeal (MTP) joints with ultrasound has been shown to improve the accuracy of assessment of rheumatoid arthritis (RA). However, the presence of intraarticular low-echoic synovial area (LESA) in the MTP joints in healthy subjects complicates the sonographic assessment of these joints. Healthy subjects with no arthritic symptoms in their MTP joints were recruited. All subjects completed a questionnaire and underwent physical examination and sonographic assessment. LESAs in the dorsal aspect of all MTP joints were measured in the longitudinal view. One thousand non-arthritic MTP joints in 100 healthy subjects (female 73, mean age 41.0 years old) were evaluated. Measurable LESAs were identified in all joints assessed. Mean length of LESA in each of the 1st-5th MTP joints was 17.8, 13.9, 11.9, 10.6, and 9.2 mm, respectively, whereas mean thickness was 2.4, 2.4, 1.8, 1.2, and 0.8 mm, respectively. Multivariate linear regression models identified the difference between 1st and 5th MTP joints as the most independently influential factor on the measurement of LESA. Our data provide the normal reference values for the measurements of LESA in Japanese, which should be taken into consideration when the synovitis in MTP joints is evaluated with ultrasound.

  4. Validation of reaction time as a measure of cognitive function and quality of life in healthy subjects and patients

    DEFF Research Database (Denmark)

    Jakobsen, Lene Holm; Sorensen, Janice Marie; Rask, Ingeborg Krarup

    2011-01-01

    Malnutrition is a common problem in hospitalized patients and is related to decreased cognitive function and impaired quality of life (QoL). We investigated the validity of reaction time as a simple bedside tool for measuring cognitive function in healthy subjects and patients, and additionally...

  5. Non-invasive perilymphatic pressure measurement in normal hearing subjects using the MMS-10 tympanic displacement analyser

    NARCIS (Netherlands)

    Rosingh, HJ; Wit, HP; Albers, FWJ

    The MMS-10 Tympanic Displacement Analyser (TDA) is a new device to measure the perilymphatic pressure of the human inner ear in a non-invasive way. In this study, the instrument was used in 50 normal hearing subjects (100 ears) in three different conditions: i) sitting upright and supine; ii) in the

  6. Effects of Blast Exposure on Subjective and Objective Sleep Measures in Combat Veterans with and without PTSD.

    Science.gov (United States)

    Stocker, Ryan P J; Paul, Benjamin T E; Mammen, Oommen; Khan, Hassen; Cieply, Marissa A; Germain, Anne

    2016-01-01

    This study examined the extent to which self-reported exposure to blast during deployment to Iraq and Afghanistan affects subjective and objective sleep measures in service members and veterans with and without posttraumatic stress disorder (PTSD). Seventy-one medication-free service members and veterans (mean age = 29.47 ± 5.76 years old; 85% men) completed self-report sleep measures and overnight polysomnographic studies. Four multivariate analyses of variance (MANOVAs) were conducted to examine the impact of blast exposure and PTSD on subjective sleep measures, measures of sleep continuity, non-rapid eye movement (NREM) sleep parameters, and rapid eye movement (REM) sleep parameters. There was no significant Blast × PTSD interaction on subjective sleep measures. Rather, PTSD had a main effect on insomnia severity, sleep quality, and disruptive nocturnal behaviors. There was no significant Blast × PTSD interaction, nor were there main effects of PTSD or Blast on measures of sleep continuity and NREM sleep. A significant PTSD × Blast interaction effect was found for REM fragmentation. The results suggest that, although persistent concussive symptoms following blast exposure are associated with sleep disturbances, self-reported blast exposure without concurrent symptoms does not appear to contribute to poor sleep quality, insomnia, and disruptive nocturnal disturbances beyond the effects of PTSD. Reduced REM sleep fragmentation may be a sensitive index of the synergetic effects of both psychological and physical insults. © 2016 American Academy of Sleep Medicine.

  7. Contrastive Lexicology.

    Science.gov (United States)

    Hartmann, R. R. K.

    This paper deals with the relation between etymologically related words in different languages. A survey is made of seven stages in the development of contrastive lexicology. These are: prelinguistic word studies, semantics, lexicography, translation, foreign language learning, bilingualism, and finally contrastive analysis. Concerning contrastive…

  8. Interface Orientation Distribution during Grain Growth in Bulk SrTiO3 Measured by Means of 3D X-Ray Diffraction Contrast Tomography

    DEFF Research Database (Denmark)

    Syha, Melanie; Rheinheimer, Wolfgang; Bäurer, Michael

    2012-01-01

    3D x-ray diffraction contrast tomography (DCT) is a non-destructive technique for the determination of grain shape and crystallography in polycrystalline bulk materials. Using this technique, a strontium titanate specimen was repeatedly measured between annealing steps.. A systematic analysis...

  9. Arterial input functions (AIFs) measured directly from arteries with low and standard doses of contrast agent, and AIFs derived from reference tissues.

    Science.gov (United States)

    Wang, Shiyang; Fan, Xiaobing; Medved, Milica; Pineda, Federico D; Yousuf, Ambereen; Oto, Aytekin; Karczmar, Gregory S

    2016-02-01

    Measurements of arterial input function (AIF) can have large systematic errors at standard contrast agent doses in dynamic contrast enhanced MRI (DCE-MRI). We compared measured AIFs from low dose (AIFLD) and standard dose (AIFSD) contrast agent injections, as well as the AIF derived from a muscle reference tissue and artery (AIFref). Twenty-two prostate cancer patients underwent DCE-MRI. Data were acquired on a 3T scanner using an mDixon sequence. Gadobenate dimeglumine was injected twice, at doses of 0.015 and 0.085 mmol/kg. Directly measured AIFs were fitted with empirical mathematical models (EMMs) and compared to the AIF derived from a muscle reference tissue (AIFref). EMMs accurately fitted the AIFs. The 1st and 2nd pass peaks were visualized in AIFLD, but not in AIFSD, thus the peak and shape of AIFSD could not be accurately measured directly. The average scaling factor between AIFSD and AIFLD in the washout phase was only 56% of the contrast dose ratio (~6:1). The shape and magnitude of AIFref closely approximated that of AIFLD after empirically determined dose-dependent normalization. This suggests that AIFref may be a good approximation of the local AIF. Copyright © 2015 Elsevier Inc. All rights reserved.

  10. Validation Study of a General Subject-matter Interest Measure: The Individual Interest Questionnaire (IIQ

    Directory of Open Access Journals (Sweden)

    Jerome I. Rotgans

    2015-12-01

    Conclusion and relevance: The results suggest that the IIQ is a reliable and valid instrument to measure individual interest across different disciplines and demonstrated adequate predictive validity for cognitive engagement and on-task behaviors and attitudes. The IIQ fills the gap in the literature for a generic instrument to measure individual interest.

  11. Prediction of walking speed using single stance force or pressure measurements in healthy subjects

    NARCIS (Netherlands)

    Keijsers, N.L.W.; Stolwijk, N.M.; Renzenbrink, G.J.; Duysens, J.

    2016-01-01

    Walking speed is one of the best measures of overall walking capacity. In plantar pressure measurements, walking speed can be assessed using contact time, but it is only moderately correlated with walking speed. The center of pressure might be of more value to indicate walking speed since walking

  12. Question order sensitivity of subjective well-being measures: focus on life satisfaction, self-rated health, and subjective life expectancy in survey instruments.

    Science.gov (United States)

    Lee, Sunghee; McClain, Colleen; Webster, Noah; Han, Saram

    2016-10-01

    This study examines the effect of question context created by order in questionnaires on three subjective well-being measures: life satisfaction, self-rated health, and subjective life expectancy. We conducted two Web survey experiments. The first experiment (n = 648) altered the order of life satisfaction and self-rated health: (1) life satisfaction asked immediately after self-rated health; (2) self-rated health immediately after life satisfaction; and (3) two items placed apart. We examined their correlation coefficient by experimental condition and further examined its interaction with objective health. The second experiment (n = 479) asked life expectancy before and after parental mortality questions. Responses to life expectancy were compared by order using ANOVA, and we examined interaction with parental mortality status using ANCOVA. Additionally, response time and probes were examined. Correlation coefficients between self-rated health and life satisfaction differed significantly by order: 0.313 (life satisfaction first), 0.508 (apart), and 0.643 (self-rated health first). Differences were larger among respondents with chronic conditions. Response times were the shortest when self-rated health was asked first. When life expectancy asked after parental mortality questions, respondents reported considering parents more for answering life expectancy; and respondents with deceased parents reported significantly lower expectancy, but not those whose parents were alive. Question context effects exist. Findings suggest placing life satisfaction and self-rated health apart to avoid artificial attenuation or inflation in their association. Asking about parental mortality prior to life expectancy appears advantageous as this leads respondents to consider parental longevity more, an important factor for true longevity.

  13. Foveal slope measurements in subjects with high-risk of age-related macular degeneration

    Directory of Open Access Journals (Sweden)

    Rajiv Raman

    2013-01-01

    Full Text Available Background: Recent reports indicated that the slope of the foveal depression influences the macular pigment (MP spatial profile. MP has been shown to confer possible protection against age-related macular degeneration (ARMD because of its antioxidant properties. Aims: To study the configuration of foveal slope and the foveal thickness in fellow eyes of subjects with unilateral neovascular ARMD. Settings and design: Case-control series. Materials and Methods: The study population consisted of 30 cases aged >50, who had unilateral choroidal neovascular membrane (CNVM or disciform scar in the fellow eye and 29 controls aged >50, who had no sign of ARMD in the either eye. Using spectral-domain optical coherence tomography, foveal thickness at different locations including the central subfield foveal thickness (CSFT was noted. The foveal slopes were calculated in the six radial scans (between 0.25° and 1° retinal eccentricity as well as the 3D scan. Results: Cases had a significantly higher CSFT when compared to controls (215.1 ± 36.19 μ vs. 193.0 ± 17.38 μ, P = 0.004. On the 3D scan, the cases had shallower superior (cases 1.32 ± 0.32 vs. controls 1.45 ± 0.13, P = 0.04 and temporal slopes (cases 1.27 ± 0.21 vs. controls 1.39 ± 0.12, P = 0.01 in comparison to the controls. Conclusions: We noted a shallower superior and temporal foveal slope and a higher CSFT in the fellow eyes of subjects with a unilateral neovascular ARMD. Prospective studies observing the development of CNVM in subjects with altered foveal slope might provide more information on this optical coherence tomography finding.

  14. Simple anthropometric measures correlate with metabolic risk indicators as strongly as magnetic resonance imaging-measured adipose tissue depots in both HIV-infected and control subjects.

    Science.gov (United States)

    Scherzer, Rebecca; Shen, Wei; Bacchetti, Peter; Kotler, Donald; Lewis, Cora E; Shlipak, Michael G; Heymsfield, Steven B; Grunfeld, Carl

    2008-06-01

    Studies in persons without HIV infection have compared percentage body fat (%BF) and waist circumference as markers of risk for the complications of excess adiposity, but only limited study has been conducted in HIV-infected subjects. We compared anthropometric and magnetic resonance imaging (MRI)-based adiposity measures as correlates of metabolic complications of adiposity in HIV-infected and control subjects. The study was a cross-sectional analysis of 666 HIV-positive and 242 control subjects in the Fat Redistribution and Metabolic Change in HIV Infection (FRAM) study assessing body mass index (BMI), waist (WC) and hip (HC) circumferences, waist-to-hip ratio (WHR), %BF, and MRI-measured regional adipose tissue. Study outcomes were 3 metabolic risk variables [homeostatic model assessment (HOMA), triglycerides, and HDL cholesterol]. Analyses were stratified by sex and HIV status and adjusted for demographic, lifestyle, and HIV-related factors. In HIV-infected and control subjects, univariate associations with HOMA, triglycerides, and HDL were strongest for WC, MRI-measured visceral adipose tissue, and WHR; in all cases, differences in correlation between the strongest measures for each outcome were small (r measures, and the magnitudes of differences were small (adjusted R(2) measures with HOMA, triglycerides, and HDL cholesterol are approximately as strong as MRI-measured whole-body adipose tissue depots in both HIV-infected and control subjects.

  15. Perception of a Japanese vowel length contrast by Japanese and American English listeners: behavioral and electrophysiological measures.

    Science.gov (United States)

    Hisagi, Miwako; Shafer, Valerie L; Strange, Winifred; Sussman, Elyse S

    2010-11-11

    This study examined the role of automatic selective perceptual processes in native and non-native listeners' perception of a Japanese vowel length contrast (tado vs. taado), using multiple, natural-speech tokens of each category as stimuli in a "categorial oddball" design. Mismatch negativity (MMN) was used to index discrimination of the temporally-cued vowel contrast by naïve adult American listeners and by a native Japanese-speaking control group in two experiments in which attention to the auditory input was manipulated: in Exp 1 (Visual-Attend), listeners silently counted deviants in a simultaneously-presented visual categorial oddball shape discrimination task; in Exp 2 (Auditory-Attend), listeners attended to the auditory input and implicitly counted target deviants. MMN results showed effects of language experience and attentional focus: MMN amplitudes were smaller for American compared to Japanese listeners in the Visual-Attend Condition and for the American listeners in the Visual compared to Auditory-Attend Condition. Subtle differences in topography were also seen, specifically in that the Japanese group showed more robust responses than the American listeners at left hemisphere scalp sites that probably index activity from the superior temporal gyrus. Follow-up behavioral discrimination tests showed that Americans discriminated the contrast well above chance, but more poorly than did Japanese listeners. This pattern of electrophysiological and behavioral results supports the conclusion that early experience with phonetic contrasts of a language results in changes in neural representations in the auditory cortex that allow for more robust automatic, phonetic processing of native-language speech input. Copyright © 2010 Elsevier B.V. All rights reserved.

  16. Cognitive Components Predict Virtual Reality-Induced Analgesia: Repeated Measures in Healthy Subjects

    Directory of Open Access Journals (Sweden)

    Naor Demeter

    2018-01-01

    Full Text Available Virtual reality (VR is an advanced and useful technology in the distraction from pain. The efficacy of VR for reducing pain is well established. Yet, the literature analyzing the unique attributes of VR which impact pain reduction is scarce. The present study evaluated the effect of two VR environments on experimental pain levels. Both VR environments are games used with an EyeToy application which is part of the video capture VR family. The VR environments were analyzed by expert occupational therapists using a method of activity analysis, allowing for a thorough evaluation of the VR activity performance requirements. The VR environments were found to differ in the cognitive load (CL demands they apply upon subjects. Sixty-two healthy students underwent psychophysical thermal pain tests, followed by exposure to tonic heat stimulation under one of three conditions: Low CL (LCL VR, high CL (HCL VR, and control. In addition, following participation in VR, the subjects completed a self-feedback inventory evaluating their experience in VR. The results showed significantly greater pain reduction during both VR conditions compared to the control condition (p = 0.001. Hierarchical regression revealed cognitive components which were evaluated in the self-feedback inventory to be predictive factors for pain reduction only during the high cognitive load (HCL VR environment (20.2%. CL involved in VR may predict the extent of pain decrease, a finding that should be considered in future clinical and laboratory research.

  17. 2D phase contrast blood flow velocity measurements of the thoracic vasculature: comparison of the effect of gadofosveset trisodium and gadopentetate dimeglumine.

    Science.gov (United States)

    Makowski, Marcus R; Wiethoff, Andrea J; Ebersberger, Hans U; Botnar, René M; Razavi, Reza; Schaeffter, Tobias; Greil, Gerald F

    2015-02-01

    The aim of this prospective study is to compare the performance of 2D time-resolved phase-contrast (PC) MRI prior to and after the administration of an intravascular (gadofosveset-trisodium) and extravascular (gadopentetate-dimeglumine) contrast agent in the same patient in the cardiovascular system. This study was approved by the ethics committee (Study-Number-07/Q0704/2) and registered with the MedicinesAndHealthcareProductsRegulatoryAgency (MHRA-Study-Number-28482/0002/001-0001, EudraCT-Number-2006-007042). All patients signed an informed consent. 20 patients were examined using a 1.5T MR-scanner and 32-channel-coil-technology. Gadopentetate-dimeglumine (GdD) and gadofosveset-trisodium (GdT) were administered in the same patient on consecutive days. Image quality, velocity-to-noise-ratios (VNRs) and standard-deviation of blood-flow-velocities (phase-noise) were compared between GdT, GdD and non-contrast-enhanced imaging. On both days pre- and post-contrast-scans were performed. The administration of GdT significantly improved the delineation of the perfused lumen and the VNR compared to GdD and non-contrast-enhanced imaging. Standard deviations of through-plane and in-plane velocity-measurements (phase-noise) were significantly reduced after GdT administration (p 0.05) were measured regarding absolute flow values prior to and after the administration of GdD and GdT. PC flow imaging benefits from the administration of an intravascular contrast agent by improving the delineation of the perfused lumen and reducing phase noise in flow measurements.

  18. Reproducibility and repeatability of foveal avascular zone area measurements using swept-source optical coherence tomography angiography in healthy subjects.

    Science.gov (United States)

    Mastropasqua, Rodolfo; Toto, Lisa; Mattei, Peter A; Di Nicola, Marta; Zecca, Isaia A L; Carpineto, Paolo; Di Antonio, Luca

    2017-05-11

    To assess the reproducibility and repeatability of foveal avascular zone (FAZ) area measurements using swept-source optical coherence tomography angiography (SS-OCTA) in healthy subjects. Sixty-four eyes of 64 healthy volunteers were randomly subjected to FAZ area measurements using SS-OCTA by 2 examiners in 2 different sessions. The FAZ areas measured by the first and second observer were 0.269 ± 0.092 mm2 and 0.270 ± 0.090 mm2, respectively. Within subjects, the coefficients of variations were 2.44% (95% confidence interval [CI] 1.95% to 2.93%) and 2.66% (95% CI 2.00% to 3.31%) for the first and second observers, respectively. The coefficient of repeatability average measurements of FAZ area were 0.021 mm2 and 0.024 mm2. The intraclass correlation coefficient values were 0.993 (95% CI 0.989 to 0.996) and 0.991 (95% CI 0.986 to 0.995). Interobserver and intraobserver concordance correlation coefficients ranged from 0.998 (95% CI 0.997 to 0.999) to 0.999 (95% CI 0.998 to 0.999) and from 0.989 (95% CI 0.982 to 0.993) to 0.987 (95% CI 0.979 to 0.992), respectively. The FAZ area measurements by means of SS-OCTA showed high reproducibility and repeatability in healthy eyes.

  19. Infrared Contrast Analysis Technique for Flash Thermography Nondestructive Evaluation

    Science.gov (United States)

    Koshti, Ajay

    2014-01-01

    The paper deals with the infrared flash thermography inspection to detect and analyze delamination-like anomalies in nonmetallic materials. It provides information on an IR Contrast technique that involves extracting normalized contrast verses time evolutions from the flash thermography infrared video data. The paper provides the analytical model used in the simulation of infrared image contrast. The contrast evolution simulation is achieved through calibration on measured contrast evolutions from many flat bottom holes in the subject material. The paper also provides formulas to calculate values of the thermal measurement features from the measured contrast evolution curve. Many thermal measurement features of the contrast evolution that relate to the anomaly characteristics are calculated. The measurement features and the contrast simulation are used to evaluate flash thermography inspection data in order to characterize the delamination-like anomalies. In addition, the contrast evolution prediction is matched to the measured anomaly contrast evolution to provide an assessment of the anomaly depth and width in terms of depth and diameter of the corresponding equivalent flat-bottom hole (EFBH) or equivalent uniform gap (EUG). The paper provides anomaly edge detection technique called the half-max technique which is also used to estimate width of an indication. The EFBH/EUG and half-max width estimations are used to assess anomaly size. The paper also provides some information on the "IR Contrast" software application, half-max technique and IR Contrast feature imaging application, which are based on models provided in this paper.

  20. Objective measurement of daytime napping, cognitive dysfunction and subjective sleepiness in Parkinson's disease

    National Research Council Canada - National Science Library

    Bolitho, Samuel J; Naismith, Sharon L; Salahuddin, Pierre; Terpening, Zoe; Grunstein, Ron R; Lewis, Simon J G

    2013-01-01

    .... The current study used daytime actigraphy, a novel objective measure of napping and related this to neuropsychological performance in a sample of PD patients and healthy, age and gender-matched controls...

  1. Objective Measurement of Daytime Napping, Cognitive Dysfunction and Subjective Sleepiness in Parkinsons Disease: e81233

    National Research Council Canada - National Science Library

    Samuel J Bolitho; Sharon L Naismith; Pierre Salahuddin; Zoe Terpening; Ron R Grunstein; Simon J G Lewis

    2013-01-01

    .... The current study used daytime actigraphy, a novel objective measure of napping and related this to neuropsychological performance in a sample of PD patients and healthy, age and gender-matched controls...

  2. Wealth, justice and freedom: Objective and subjective measures predicting poor mental health in a study across eight countries.

    Science.gov (United States)

    Scholten, Saskia; Velten, Julia; Neher, Torsten; Margraf, Jürgen

    2017-12-01

    Macro-level factors (MF) such as wealth, justice and freedom measured with objective country-level indicators (objective MF), for instance the Gross Domestic Product (GDP), have been investigated in relation to health and well-being, but rarely in connection with depression, anxiety and stress subsumed as poor mental health. Also, a combination of different objective MF and of how individuals perceive those MF (subjective MF) has not been taken into consideration. In the present study, we combined subjective and objective measures of wealth, justice and freedom and examined their relationship with poor mental health. Population-based interviews were conducted in France, Germany, Poland, Russia, Spain, Sweden, U.K. and U.S.A. (n ≈ 1000 per country). GDP, GINI coefficient, Justice Index and Freedom Index were used as objective MF, whereas subjective MF were perceived wealth, justice and freedom measured at the individual level. Poor mental health was assessed as a combination of symptoms of depression, anxiety and stress. In a random-intercept-model, GINI coefficient and Freedom Index were significant positive country-level, and perceived wealth, justice, and freedom significant negative individual-level predictors of symptoms of poor mental health. Multiple subjective and objective MF should be combined to assess the macrosystem's relationship with poor mental health more precisely. The relationship between MF and poor mental health indicates that the macrosystem should be taken into account as relevant context for mental health problems, too.

  3. Subjective and Objective Measures in the Treatment of Hemifacial Spasm With OnabotulinumtoxinA.

    Science.gov (United States)

    Chundury, Rao V; D'Angelo, Alexander S; Couch, Steven M; Holds, John B

    2016-01-01

    To evaluate the Sunnybrook Facial Grading System (SFGS) and Facial Clinimetric Evaluation (FaCE) Scale Instrument outcomes when treating hemifacial spasm (HFS) with onabotulinumtoxinA. An Institutional Review Board-approved retrospective review of records of 66 HFS patients treated with onabotulinumtoxinA. SFGS and FaCE surveys were completed prior to onabotulinumtoxinA therapy and at 1 month follow up. Surveys were analyzed for differences using paired Student t tests, with statistical significance set at p < 0.05. Correlations were determined using Spearman correlation (rs), with coefficients of ≥0.40 or ≤-0.40 considered significant. There were 22 complete data sets. SFGS composite score improved from mean, 56.9 (SD, 12.3) to 63.6 (SD, 12.3), p < 0.01. SFGS subdomain synkinesis score significantly improved (p < 0.01). The FaCE scale subdomain oral function significantly worsened (p = 0.05). The Δ pre-/post-SFGS composite score did not correlate with the Δ pre-/post-FaCE composite score (rs = 0.24). There was a significant positive correlation between SFGS composite score and FaCE social function score (rs = 0.462, p = 0.03) and between SFGS voluntary movement score and FaCE social function score (rs = 0.477, p = 0.03). Subgroup analysis of single FaCE questions demonstrated no statistical change in subjective dry eye (p = 0.30). There was an improvement in social functioning in treated HFS patients, which positively correlated with improvement in overall objective voluntary facial movement. There was no statistical difference in subjective dry eye symptoms. The overall SFGS composite score improved following treatment of HFS with botulinum toxin. This information can be used when counseling expected outcomes in HFS patients treated with onabotulinumtoxinA.

  4. Benefits of a short, practical questionnaire to measure subjective perception of nasal appearance after aesthetic rhinoplasty.

    Science.gov (United States)

    Lohuis, Peter J F M; Hakim, Sara; Duivesteijn, Wouter; Knobbe, Arno; Tasman, Abel-Jan

    2013-12-01

    The authors tested a short, practically designed questionnaire to assess changes in subjective perception of nasal appearance in patients before and after aesthetic rhinoplasty. A prospective cohort study was conducted in a group of 121 patients who desired aesthetic rhinoplasty and were operated on by one surgeon. The questionnaire contained five questions (E1-E5) based on a five-point Likert scale and a visual analogue scale (range, 0 to 10). Two questions were designed as trick questions to help the surgeon screen for signs of body dysmorphic disorder. All patients rated the appearance of their nose as improved after surgery. The visual analogue scale revealed a Gaussian curve of normal distribution (range, 0.5 to 10) around a significant improvement (mean, 4.36 points, p = 0.018). Also, question E1, question E2, and the sum of questions E1 through E5 showed a statistically significant improvement after surgery (p = 1.74 × 10, p = 4.29 × 10, and p = 9.23 × 10, respectively). The authors found a linear relationship between preoperative score on the trick questions and postoperative increase in visual analogue scale score. Test-retest reliability could be investigated in 74 of 121 patients (61 percent) and showed a positive correlation between postoperative (1 year after surgery) and repostoperative response (2 to 4 years after surgery). The authors concluded that a surgeon performing aesthetic rhinoplasty can benefit from using this questionnaire. It is simple, takes no more than 2 minutes to complete, and provides helpful subjective information regarding patients' preoperative nasal appearance and postoperative surgical outcome. Therapeutic, IV.

  5. Hemodynamic measurement using four-dimensional phase-contrast MRI: Quantification of hemodynamic parameters and clinical applications

    Energy Technology Data Exchange (ETDEWEB)

    Ha, Ho Jin; Lee, Sang Joon [POSTECH Biotech Center, Pohang University of Science and Technology, Pohang (Korea, Republic of); Kim, Guk Bae; Kweon, Ji Hoon; Kim, Young Hak; Lee, Deok Hee; Yang, Dong Hyun; KIm, Nam Kug [Asan Medical Center, University of Ulsan College of Medicine, Seoul (Korea, Republic of)

    2016-07-15

    Recent improvements have been made to the use of time-resolved, three-dimensional phase-contrast (PC) magnetic resonance imaging (MRI), which is also named four-dimensional (4D) PC-MRI or 4D flow MRI, in the investigation of spatial and temporal variations in hemodynamic features in cardiovascular blood flow. The present article reviews the principle and analytical procedures of 4D PC-MRI. Various fluid dynamic biomarkers for possible clinical usage are also described, including wall shear stress, turbulent kinetic energy, and relative pressure. Lastly, this article provides an overview of the clinical applications of 4D PC-MRI in various cardiovascular regions.

  6. Hemodynamic Measurement Using Four-Dimensional Phase-Contrast MRI: Quantification of Hemodynamic Parameters and Clinical Applications

    Energy Technology Data Exchange (ETDEWEB)

    Ha, Hojin [POSTECH Biotech Center, Pohang University of Science and Technology, Pohang 37673 (Korea, Republic of); Kim, Guk Bae [Asan Institute of Life Science, Asan Medical Center, University of Ulsan College of Medicine, Seoul 05505 (Korea, Republic of); Kweon, Jihoon [Department of Cardiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul 05505 (Korea, Republic of); Lee, Sang Joon [POSTECH Biotech Center, Pohang University of Science and Technology, Pohang 37673 (Korea, Republic of); Department of Mechanical Engineering, Pohang University of Science and Technology, Pohang 37673 (Korea, Republic of); Kim, Young-Hak [Department of Cardiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul 05505 (Korea, Republic of); Lee, Deok Hee; Yang, Dong Hyun [Department of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul 05505 (Korea, Republic of); Kim, Namkug [Department of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul 05505 (Korea, Republic of); Department of Convergence Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul 05505 (Korea, Republic of)

    2016-11-01

    Recent improvements have been made to the use of time-resolved, three-dimensional phase-contrast (PC) magnetic resonance imaging (MRI), which is also named four-dimensional (4D) PC-MRI or 4D flow MRI, in the investigation of spatial and temporal variations in hemodynamic features in cardiovascular blood flow. The present article reviews the principle and analytical procedures of 4D PC-MRI. Various fluid dynamic biomarkers for possible clinical usage are also described, including wall shear stress, turbulent kinetic energy, and relative pressure. Lastly, this article provides an overview of the clinical applications of 4D PC-MRI in various cardiovascular regions.

  7. The effects of receiver placement on probe microphone, performance, and subjective measures with open canal hearing instruments.

    Science.gov (United States)

    Alworth, Lynzee N; Plyler, Patrick N; Reber, Monika Bertges; Johnstone, Patti M

    2010-04-01

    Open canal hearing instruments differ in method of sound delivery to the ear canal, distance between the microphone and the receiver, and physical size of the devices. Moreover, RITA (receiver in the aid) and RITE (receiver in the ear) hearing instruments may also differ in terms of retention and comfort as well as ease of use and care for certain individuals. What remains unclear, however, is if any or all of the abovementioned factors contribute to hearing aid outcome. To determine the effect of receiver location on performance and/or preference of listeners using open canal hearing instruments. An experimental study in which subjects were exposed to a repeated measures design. Twenty-five adult listeners with mild sloping to moderately severe sensorineural hearing loss (mean age 67 yr). Participants completed two six-week trial periods for each device type. Probe microphone, objective, and subjective measures (quiet, noise) were conducted unaided and aided at the end of each trial period. Occlusion effect results were not significantly different between the RITA and RITE instruments; however, frequency range was extended in the RITE instruments, resulting in significantly greater maximum gain for the RITE instruments than the RITA instruments at 4000 and 6000 Hz. Objective performance in quiet or in noise was unaffected by receiver location. Subjective measures revealed significantly greater satisfaction ratings for the RITE than for the RITA instruments. Similarly, preference in quiet and overall preference were significantly greater for the RITE than for the RITA instruments. Although no occlusion differences were noted between instruments, the RITE did demonstrate a significant difference in reserve gain before feedback at 4000 and 6000 Hz. Objectively; no positive benefit was noted between unaided and aided conditions on speech recognition tests. These results suggest that such testing may not be sensitive enough to determine aided benefit with open canal

  8. Topography, complex refractive index, and conductivity of graphene layers measured by correlation of optical interference contrast, atomic force, and back scattered electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Vaupel, Matthias, E-mail: Matthias.vaupel@zeiss.com; Dutschke, Anke [Training Application Support Center, Carl Zeiss Microscopy GmbH, Königsallee 9-21, 37081 Göttingen (Germany); Wurstbauer, Ulrich; Pasupathy, Abhay [Department of Physics, Columbia University New York, 538 West 120th Street, New York, New York 10027 (United States); Hitzel, Frank [DME Nanotechnologie GmbH, Geysostr. 13, D-38106 Braunschweig (Germany)

    2013-11-14

    The optical phase shift by reflection on graphene is measured by interference contrast microscopy. The height profile across graphene layers on 300 nm thick SiO{sub 2} on silicon is derived from the phase profile. The complex refractive index and conductivity of graphene layers on silicon with 2 nm thin SiO{sub 2} are evaluated from a phase profile, while the height profile of the layers is measured by atomic force microscopy. It is observed that the conductivity measured on thin SiO{sub 2} is significantly greater than on thick SiO{sub 2}. Back scattered electron contrast of graphene layers is correlated to the height of graphene layers.

  9. Effect of Single Administration of Coffee on Pupil Size and Ocular Wavefront Aberration Measurements in Healthy Subjects

    Directory of Open Access Journals (Sweden)

    Handan Bardak

    2016-01-01

    Full Text Available No study has so far evaluated the impact of coffee drinking on ocular wavefront aberration (OWA measurements. This study presents novel findings regarding the OWA of the eye following coffee intake. We aimed to evaluate the acute changes in pupil size and OWA of the eye after single administration of coffee. A total of 30 otherwise healthy participants were included in this prospective study. All subjects drank a cup of coffee containing 57 mg caffeine. Measurements of pupil size, total coma (TC, total trefoil (TF, total spherical aberration (TSA, and total higher order aberration (HOA were performed before and at 5 minutes, at 30 minutes, and at 4 hours after coffee drinking using a wavefront aberrometer device (Irx3, Imagine Eyes, Orsay, France. The mean age of the study population was 20.30 ± 2.74 years. Pupil size did not show a significant change during the measurements (p>0.05. A significant increase was observed in TF and HOA measurements following coffee intake (p=0.029 and p=0.009, resp.. Single administration of coffee results in significant increase in TF and total HOAs in healthy subjects without any effect on pupil diameter. Ultrastructural changes in the cornea following coffee intake might be of relevance to the alterations in ocular aberrations in healthy subjects.

  10. [Partial k-space sampling with zero filling used with phase-contrast flow measurements: in vivo and in vitro validation].

    Science.gov (United States)

    Pertschy, S; Meyer, G P; Waalkes, S; Doeker, R; Koshedub, R; Noeske, R; Galanski, M; Lotz, J

    2006-07-01

    To validate the technique of partial k-space sampling and zero filling with phase-contrast flow measurements as compared to measurements with full k-space sampling. In vitro: A laminar flow phantom was utilized to evaluate the effect of partial k-space sampling on the accuracy, precision and signal-to-noise ratio of phase-contrast flow measurements. In vivo: The effect of partial k-space sampling on the quantification of cardiac output (n = 40 patients) and the duration of the scan were evaluated in the ascending aorta (n = 37) and pulmonary trunk (n = 34) in a prospective study. Partial k-space sampling resulted in an increase in the SNR by 2 % in vitro. The precision was altered by less than 1 %. Flow volumes were systematically overestimated by 3.5 %. No significant differences were found in the in vivo measurements of cardiac output. The scan duration was reduced by 34 % by utilizing partial k-space sampling. Partial k-space sampling can be used to reduce scan time without a significant decrease in the accuracy or precision of phase-contrast flow measurements in large arteries.

  11. Comparison between ankle proprioception measurements and postural sway test for evaluating ankle instability in subjects with functional ankle instability.

    Science.gov (United States)

    Kim, Chang-Yong; Choi, Jong-Duk

    2016-01-01

    It is important to establish the effective evaluation approaches that are appropriate for measuring ankle proprioception. But, only a few studies used more than one test procedure simultaneously to identify proprioceptive deficits. Further, no data are available on the correlations between the measures of ankle proprioception and postural sway (PS) test in subjects with functional ankle instability (FAI). The aim of this study was to identify the relationship between ankle proprioception measurements and PS test in subjects with FAI. Of the 79 subjects enrolled in the case-control study, 40 had FAI and 39 were control subjects. Ankle proprioception was evaluated by the angle reproduction (AR), force matching (FM), and the muscle reaction (MR) to sudden ankle inversion tests. For the AR and FM tests, absolute errors (AE) of ankle plantarflexion, dorsiflexion, inversion, and eversion directions were calculated. For the MR test, reaction times and activation of tibialis anterior (TA), peroneus longus (PL), and peroneus brevis (PB) muscles were measured during sudden ankle inversion with a 30° tilting angle. The PS test was investigated by using a force platform during single-limb standing test. Three trials were performed and averaged in each test. Reaction time of the PL (p = 0.006), a variable of MR test, and plantarflexion (p = 0.001, p = 0.009) and eversion (p = 0.016, p = 0.039) error variables of the AR and FM tests differed significantly between the control and FAI groups. Moreover, these variables (r = -0.381 ∼ 0.788, p proprioception measurements were more sensitive and discriminative than others, and could be useful to assess ankle instability, particularly if the method is to be applied in clinical studies and laboratory settings.

  12. Relationship Between Pretraining Subjective Wellness Measures, Player Load, and Rating-of-Perceived-Exertion Training Load in American College Football.

    Science.gov (United States)

    Govus, Andrew D; Coutts, Aaron; Duffield, Rob; Murray, Andrew; Fullagar, Hugh

    2018-01-01

    The relationship between pretraining subjective wellness and external and internal training load in American college football is unclear. To examine the relationship of pretraining subjective wellness (sleep quality, muscle soreness, energy, wellness Z score) with player load and session rating of perceived exertion (s-RPE-TL) in American college football players. Subjective wellness (measured using 5-point, Likert-scale questionnaires), external load (derived from GPS and accelerometry), and s-RPE-TL were collected during 3 typical training sessions per week for the second half of an American college football season (8 wk). The relationship of pretraining subjective wellness with player load and s-RPE training load was analyzed using linear mixed models with a random intercept for athlete and a random slope for training session. Standardized mean differences (SMDs) denote the effect magnitude. A 1-unit increase in wellness Z score and energy was associated with trivial 2.3% (90% confidence interval [CI] 0.5, 4.2; SMD 0.12) and 2.6% (90% CI 0.1, 5.2; SMD 0.13) increases in player load, respectively. A 1-unit increase in muscle soreness (players felt less sore) corresponded to a trivial 4.4% (90% CI -8.4, -0.3; SMD -0.05) decrease in s-RPE training load. Measuring pretraining subjective wellness may provide information about players' capacity to perform in a training session and could be a key determinant of their response to the imposed training demands American college football. Hence, monitoring subjective wellness may aid in the individualization of training prescription in American college football players.

  13. Automated short-axis cardiac magnetic resonance image acquisitions: accuracy of left ventricular dimension measurements in normal subjects and patients.

    Science.gov (United States)

    Danilouchkine, Mikhail G; Westenberg, Jos J M; Reiber, Johan H C; Lelieveldt, Boudewijn P F

    2004-12-01

    This study investigates the use of an automated observer-independent planning system for short-axis cardiovascular magnetic resonance (MR) acquisitions in the clinical environment. The capacity of the automated method to produce accurate measurements of left ventricular dimensions and function was quantitatively assessed in normal subjects and patients. Fourteen healthy volunteers and 8 patients underwent cardiovascular MR (CMR) acquisitions for ventricular function assessment. Short-axis datasets of the left ventricle (LV) were acquired in 2 ways: manually planned and generated in an automatic fashion. End-diastolic volume (EDV), end-systolic volume (ESV), ejection fraction (EF), and left ventricular mass (LVM) were derived from the 2 datasets. The agreement between the manual and automatic planning methods was assessed. The mean differences between the manual and automated CMR planning methods for the normal subjects and patients were 5.89 mL and 1.93 mL (EDV), 1.14 mL and -0.41 mL (ESV), 0.81% and 0.89% (EF), and 4.35 g and 3.88 g (LVM), respectively. There was no significant difference in ESV and EF. LVM significantly differed in both groups, whereas EDV was significantly different in the normal subjects and insignificantly different in the patients. The variability coefficients were 2.8 and 3.59 (EDV), 3.3 and 5.03 (ESV), 1.79 and 2.65 (EF), and 4.36 and 2.27 (LVM) for the normal subjects and patients, respectively. The mean angular deviation of the LV axes turned out to be 8.58 +/- 5.76 degrees for the normal subjects and 8.35 +/- 5.15 degrees for the patients. Automated CMR planning method can provide accurate measurements of LV dimensions in normal subjects and patients, and therefore, can be used in the clinical environment for functional assessment of the human cardiovascular system.

  14. Effect of quality of life measures on the decision to remove third molars in subjects with mild pericoronitis symptoms.

    Science.gov (United States)

    Tang, Dana T; Phillips, Ceib; Proffit, William R; Koroluk, Lorne D; White, Raymond P

    2014-07-01

    To assess how quality of life (QoL) measures affect the decision for third molar (3M) removal in patients with mild symptoms of pericoronitis. Healthy subjects, aged 18 to 35 years, with mild symptoms of pericoronitis were enrolled in an institutional review board-approved study. The demographic, clinical, and QoL data were collected at enrollment. The subjects voluntarily scheduled surgery for 3M removal. The principal outcome variable was their decision to undergo or not undergo surgery within 6 months of enrollment. The possible predictor variables in a multivariate logistic regression analysis were the demographic characteristics, dental insurance, and QoL measures. The mean age of the 113 subjects was 23.2 ± 3.8 years. Of the 113 subjects, 79 elected to undergo 3M removal within 6 months of enrollment (removed group) and 34 elected to retain their 3M at 6 months after enrollment (retained group). A significantly greater proportion of the removed group were white (58% vs 35%; P = .03) and reported having at least "a little trouble" with opening their mouths (38% vs 18%; P = .04) and taking part in social life (27% vs 6%; P = .01). The multivariate logistic regression model suggested the odds of electing 3M removal within 6 months of enrollment were greater for those who were white (odds ratio [OR] 2.69, 95% confidence interval [CI] 1.14 to 6.32) and those who had at least "a little trouble" with interactions in their social life (OR 3.22, 95% CI 1.08 to 9.58). In subjects with mild pericoronitis symptoms, experiencing problems with oral function and lifestyle, factors not often considered by clinicians, were significantly associated with subjects' decision for early 3M removal. Copyright © 2014 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

  15. The effect of subjective awareness measures on performance in artificial grammar learning task.

    Science.gov (United States)

    Ivanchei, Ivan I; Moroshkina, Nadezhda V

    2018-01-01

    Systematic research into implicit learning requires well-developed awareness-measurement techniques. Recently, trial-by-trial measures have been widely used. However, they can increase complexity of a study because they are an additional experimental variable. We tested the effects of these measures on performance in artificial grammar learning study. Four groups of participants were assigned to different awareness measures conditions: confidence ratings, post-decision wagering, decision strategy attribution or none. Decision-strategy-attribution participants demonstrated better grammar learning and longer response times compared to controls. They also exhibited a conservative bias. Grammaticality by itself was a stronger predictor of strings endorsement in decision-strategy-attribution group compared to other groups. Confidence ratings and post-decision wagering only affected the response times. These results were supported by an additional experiment that used a balanced chunk strength design. We conclude that a decision-strategy-attribution procedure may force participants to adopt an analytical decision-making strategy and rely mostly on conscious knowledge of artificial grammar. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. Measuring craving: An attempt to connect subjective craving with cue reactivity

    NARCIS (Netherlands)

    Ooteman, W.; Koeter, M.W.J.; Vserheul, R.; Schippers, G.M.; van den Brink, W.

    2006-01-01

    Background: Better insight into craving may contribute to the development of more efficient relapse prevention strategies. Inconsistent findings on the relation between craving and relapse may be due to difficulties in the measurement of craving. These difficulties are accounted for by 3

  17. Contrast induced nephropathy

    DEFF Research Database (Denmark)

    Stacul, Fulvio; van der Molen, Aart J; Reimer, Peter

    2011-01-01

    PURPOSE: The Contrast Media Safety Committee (CMSC) of the European Society of Urogenital Radiology (ESUR) has updated its 1999 guidelines on contrast medium-induced nephropathy (CIN). AREAS COVERED: Topics reviewed include the definition of CIN, the choice of contrast medium, the prophylactic...... measures used to reduce the incidence of CIN, and the management of patients receiving metformin. Key Points • Definition, risk factors and prevention of contrast medium induced nephropathy are reviewed. • CIN risk is lower with intravenous than intra-arterial iodinated contrast medium. • eGFR of 45 ml....../min/1.73 m (2) is CIN risk threshold for intravenous contrast medium. • Hydration with either saline or sodium bicarbonate reduces CIN incidence. • Patients with eGFR ≥ 60 ml/min/1.73 m (2) receiving contrast medium can continue metformin normally....

  18. Contrast induced nephropathy

    DEFF Research Database (Denmark)

    Stacul, Fulvio; van der Molen, Aart J; Reimer, Peter

    2011-01-01

    PURPOSE: The Contrast Media Safety Committee (CMSC) of the European Society of Urogenital Radiology (ESUR) has updated its 1999 guidelines on contrast medium-induced nephropathy (CIN). AREAS COVERED: Topics reviewed include the definition of CIN, the choice of contrast medium, the prophylactic...... measures used to reduce the incidence of CIN, and the management of patients receiving metformin. Key Points • Definition, risk factors and prevention of contrast medium induced nephropathy are reviewed. • CIN risk is lower with intravenous than intra-arterial iodinated contrast medium. • eGFR of 45 ml....../min/1.73 m (2) is CIN risk threshold for intravenous contrast medium. • Hydration with either saline or sodium bicarbonate reduces CIN incidence. • Patients with eGFR = 60 ml/min/1.73 m (2) receiving contrast medium can continue metformin normally....

  19. Influence of academic examination stress on hematological measurements in subjectively healthy volunteers.

    Science.gov (United States)

    Maes, M; Van Der Planken, M; Van Gastel, A; Bruyland, K; Van Hunsel, F; Neels, H; Hendriks, D; Wauters, A; Demedts, P; Janca, A; Scharpé, S

    1998-09-21

    Some recent reports showed that a brief exposure to a mental stressor during 3-20 min may induce hematological changes in humans. The aim of the present study was to examine the effects of academic examination stress on erythron variables, such as the number of red blood cells (RBC), hemoglobin (Hb), hematocrit (Ht), mean corpuscular volume (MCV), mean cell Hb (MCH), mean cell Hb concentration (MCHC), RBC distribution width (RDW), and serum iron and transferrin (Tf). The above variables were determined in 41 students in three conditions, i.e. the stress condition (the day before a difficult oral exam) and two baseline conditions, i.e. a few weeks earlier and later. At the same occasions, subjects completed the Perceived Stress Scale (PSS), the state version of the State-Trait Anxiety Inventory (STAI) and the Profile of Mood States (POMS). Academic examination stress significantly increased Ht, Hb, MCV, MCH and MCHC and significantly decreased RDW. There were significant relationships between the stress-induced changes in the PSS, STAI and POMS scores and those in Ht, Hb, MCV and MCH (allpositive) and RDW (negative). It is concluded that academic examination stress induces significant hematological changes indicative of an increased number of large RBC and increased hemoglobinisation, which cannot be explained by shifts of fluid out of the intravascular space, concentrating non-diffusible blood constituents.

  20. Associated factors of atrophic gastritis diagnosed by double-contrast upper gastrointestinal barium X-ray radiography: a cross-sectional study analyzing 6,901 healthy subjects in Japan.

    Directory of Open Access Journals (Sweden)

    Nobutake Yamamichi

    Full Text Available Double-contrast upper gastrointestinal barium X-ray radiography (UGI-XR is one of the most widely conducted gastric cancer screening methods. It has been executed to find gastric cancer, but has not been usually executed to detect premalignant atrophic mucosa of stomach. To understand the meaning of UGI-XR-based atrophic gastritis, we analyzed its association with several causative factors including Helicobacter pylori (HP infection.We evaluated 6,901 healthy adults in Japan. UGI-XR-based atrophic gastritis was diagnosed based on the irregular shape of areae gastricae and its expansion in the stomach.Of the 6,433 subjects with no history of HP eradication and free from gastric acid suppressants, 1,936 were diagnosed as UGI-XR-based atrophic gastritis (mild: 234, moderate: 822, severe: 880. These were univariately associated with serum HP IgG and serum pepsinogen I/II ratio with statistical significance. The multiple logistic analysis calculating standardized coefficients (β and odds ratio (OR demonstrated that serum HP IgG (β = 1.499, OR = 4.48, current smoking (β = 0.526, OR = 1.69, age (β = 0.401, OR = 1.49, low serum pepsinogen I/II ratio (β = 0.339, OR = 1.40, and male gender (β = 0.306, OR = 1.36 showed significant positive association with UGI-XR-based atrophic gastritis whereas drinking and body mass index did not. Among the age/sex/smoking/drinking-matched 227 pairs derived from chronically HP-infected and successfully HP-eradicated subjects, UGI-XR-based atrophic gastritis was detected in 99.1% of the former but in only 59.5% of the latter subjects (p<0.0001. Contrastively, UGI-XR-based atrophic gastritis was detected in 13 of 14 HP-positive proton pump inhibitor users (92.9% and 33 of 34 HP-positive histamine H2-receptor antagonist users (97.1%, which are not significantly different from gastric acid suppressant-free subjects.The presence of UGI-XR-based atrophic gastritis is positively

  1. Degradation data analysis based on a generalized Wiener process subject to measurement error

    Science.gov (United States)

    Li, Junxing; Wang, Zhihua; Zhang, Yongbo; Fu, Huimin; Liu, Chengrui; Krishnaswamy, Sridhar

    2017-09-01

    Wiener processes have received considerable attention in degradation modeling over the last two decades. In this paper, we propose a generalized Wiener process degradation model that takes unit-to-unit variation, time-correlated structure and measurement error into considerations simultaneously. The constructed methodology subsumes a series of models studied in the literature as limiting cases. A simple method is given to determine the transformed time scale forms of the Wiener process degradation model. Then model parameters can be estimated based on a maximum likelihood estimation (MLE) method. The cumulative distribution function (CDF) and the probability distribution function (PDF) of the Wiener process with measurement errors are given based on the concept of the first hitting time (FHT). The percentiles of performance degradation (PD) and failure time distribution (FTD) are also obtained. Finally, a comprehensive simulation study is accomplished to demonstrate the necessity of incorporating measurement errors in the degradation model and the efficiency of the proposed model. Two illustrative real applications involving the degradation of carbon-film resistors and the wear of sliding metal are given. The comparative results show that the constructed approach can derive a reasonable result and an enhanced inference precision.

  2. An experiential thinking style: its facets and relations with objective and subjective criterion measures.

    Science.gov (United States)

    Norris, Paul; Epstein, Seymour

    2011-10-01

    In Study 1, an experiential factor divided into the following 3 factors when 3 or more factors were extracted: intuition, emotionality, and imagination; whereas a rational factor retained its coherence. In Study 2, an experiential but not a rational thinking style was positively associated with performance measures of creativity, humor, aesthetic judgment, and intuition and with self-report measures of empathy and social popularity. A rational thinking style was associated with several measures of adjustment. Both thinking styles were positively related to personal growth. Support was provided from several sources for the discriminant validity of the experiential facets. In a third study, the independence of the 2 thinking styles and of gender differences in self-reported data were verified by observations by others of participants' thinking styles. The importance of identifying facets of an experiential thinking style and of discovering previously unrecognized favorable attributes of this thinking style was discussed. © 2011 The Authors. Journal of Personality © 2011, Wiley Periodicals, Inc.

  3. A History of In Vivo Neutron Activation Analysis in Measurement of Aluminum in Human Subjects.

    Science.gov (United States)

    Mohseni, Hedieh K; Chettle, David R

    2016-01-01

    Aluminum, as an abundant metal, has gained widespread use in human life, entering the body predominantly as an additive to various foods and drinking water. Other major sources of exposure to aluminum include medical, cosmetic, and occupational routes. As a common environmental toxin, with well-known roles in several medical conditions such as dialysis encephalopathy, aluminum is considered a potential candidate in the causality of Alzheimer's disease. Aluminum mostly accumulates in the bone, which makes bone an indicator of the body burden of aluminum and an ideal organ as a proxy for the brain. Most of the techniques developed for measuring aluminum include bone biopsy, which requires invasive measures, causing inconvenience for the patients. There has been a considerable effort in developing non-invasive approaches, which allow for monitoring aluminum levels for medical and occupational purposes in larger populations. In vivo neutron activation analysis, a method based on nuclear activation of isotopes of elements in the body and their subsequent detection, has proven to be an invaluable tool for this purpose. There are definite challenges in developing in vivo non-invasive techniques capable of detecting low levels of aluminum in healthy individuals and aluminum-exposed populations. The following review examines the method of in vivo neutron activation analysis in the context of aluminum measurement in humans focusing on different neutron sources, interference from other activation products, and the improvements made in minimum detectable limits and patient dose over the past few decades.

  4. Subjective reports versus objective measurement of sleep latency and sleep duration in pregnancy.

    Science.gov (United States)

    Wilson, Danielle L; Fung, Alison; Walker, Susan P; Barnes, Maree

    2013-01-01

    This study compared self-reported sleep latency (SL) and total sleep time (TST) to objective measures on polysomnography (PSG) during pregnancy. Thirty-three women in the third trimester (T3) of pregnancy, 16 women in the first trimester (T1) of pregnancy, and 15 non-pregnant women underwent overnight PSG, and shortly after awakening reported their perceived SL and TST. Results showed that, on average, the T3 group slightly overestimated their TSTs, whereas the T1 and non-pregnant groups underestimated TSTs when compared with objective measurement. All groups overestimated SL, and perceived SL was closest to the first epoch of 10 min of uninterrupted sleep or the first epoch of slow-wave sleep, rather than the first epoch of sleep (the current definition used for diagnostic sleep studies). The wide variation in discrepancies between estimation and PSG measurement for both TST and SL shows that self-reports made by both pregnant and non-pregnant women tend to be unreliable, which has important implications both clinically and for the many studies based on self-reported sleep patterns in pregnancy.

  5. Improvement of phase-contrast flow measurements. Opposite directional flow-encoding technique to eliminate the influence of the maxwell term phase errors

    Energy Technology Data Exchange (ETDEWEB)

    Yukawa, Osamu [Hiroshima General Hospital (Japan)

    2001-02-01

    A new method termed the opposite directional flow-encoding (ODFE) technique is proposed to increase the accuracy and the reproducibility of phase-contrast flow measurements by correcting the non-linear background of velocity images induced by concomitant magnetic fields (Maxwell terms). In this technique, the volume flow rate is calculated from the difference of two region of interest (ROI) values derived from two velocity images obtained by reversing the flow-encoding direction. To evaluate the technique, various phantom experiments were carried out and volume blood flow rates of internal carotid arteries (ICAs) were measured in four volunteers. The technique could measure the volume flow rates of the phantom with higher accuracy (mean absolute percentage error =1.04%) and reproducibility (coefficient of variation =1.18%) than conventional methods. Flow measurements with the technique was not significantly affected by ROI size variation, measuring position, and flow obliquity not exceeding 30 deg. The volume flow rates in the ICAs of a volunteer were measured with high reproducibility (coefficient of variation =2.89% on the right, 1.48% on the left), and the flow measurement was not significantly affected by ROI size variation. The ODFE technique can minimize the effect of the non-linear background due to Maxwell terms. The technique allows use of ROIs of approximate size including the flow signal and provides accurate and objective phase-contrast flow measurements. (author)

  6. Noncontrast-enhanced magnetic resonance renal angiography using a repetitive artery and venous labelling technique at 3 T: comparison with contrast-enhanced magnetic resonance angiography in subjects with normal renal function.

    Science.gov (United States)

    Park, Sung Yoon; Kim, Chan Kyo; Kim, EunJu; Park, Byung Kwan

    2015-02-01

    To investigate the feasibility of noncontrast-enhanced MR angiography (NC-MRA) using the repetitive artery and venous labelling (RAVEL) technique to evaluate renal arteries compared to contrast-enhanced MR angiography (CE-MRA). Twenty-five subjects with normal renal function underwent NC-MRA using a RAVEL technique and CE-MRA at 3 T. Two independent readers analysed the MRA images. Image quality, number of renal arteries, presence or absence of an early branching vessel, and diameter of the main renal arteries were evaluated. The overall image quality of NC-MRA was fair or greater in 88% of right and 92% of left renal arteries, while it was 96% in both sides with CE-MRA. On NC-MRA, the number of renal arteries in all subjects was perfectly predicted by both readers. Sensitivity and specificity for predicting early branching vessels were 82% and 100% for reader 1 and 82% and 95% for reader 2. Inter-modality agreement for comparing the diameters of main renal arteries was good or excellent at all segments for both readers. Inter-reader agreement was moderate or good at all segments except at the right distal segment on NC-MRA. NC-MRA with the RAVEL technique at 3 T may have comparable diagnostic feasibility for evaluating renal arteries compared to CE-MRA. • Accurate pre-treatment evaluation of renal artery anatomy helps clinical decision-making. • NC-MRA using RAVEL offers acceptable imaging quality for renal artery evaluation. • The 3 T RAVEL technique provides excellent diagnostic performance for renal artery evaluation. • The 3 T RAVEL technique may be an alternative to contrast-enhanced MRA.

  7. Wealth, justice and freedom: Objective and subjective measures predicting poor mental health in a study across eight countries

    OpenAIRE

    Saskia Scholten; Julia Velten; Torsten Neher; Jürgen Margraf

    2017-01-01

    Background: Macro-level factors (MF) such as wealth, justice and freedom measured with objective country-level indicators (objective MF), for instance the Gross Domestic Product (GDP), have been investigated in relation to health and well-being, but rarely in connection with depression, anxiety and stress subsumed as poor mental health. Also, a combination of different objective MF and of how individuals perceive those MF (subjective MF) has not been taken into consideration. In the present s...

  8. Wealth, justice and freedom: Objective and subjective measures predicting poor mental health in a study across eight countries

    OpenAIRE

    Scholten, Saskia; Velten, Julia; Neher, Torsten; Margraf, Jürgen

    2017-01-01

    Background Macro-level factors (MF) such as wealth, justice and freedom measured with objective country-level indicators (objective MF), for instance the Gross Domestic Product (GDP), have been investigated in relation to health and well-being, but rarely in connection with depression, anxiety and stress subsumed as poor mental health. Also, a combination of different objective MF and of how individuals perceive those MF (subjective MF) has not been taken into consideration. In the present st...

  9. Fatigue in Emergency Services Operations: Assessment of the Optimal Objective and Subjective Measures Using a Simulated Wildfire Deployment

    Directory of Open Access Journals (Sweden)

    Sally A. Ferguson

    2016-01-01

    Full Text Available Under controlled laboratory conditions, neurobehavioral assays such as the Psychomotor Vigilance Task (PVT are sensitive to increasing levels of fatigue, and in general, tend to correlate with subjective ratings. However, laboratory studies specifically curtail physical activity, potentially limiting the applicability of such findings to field settings that involve physical work. In addition, laboratory studies typically involve healthy young male participants that are not always representative of a typical working population. In order to determine whether these findings extend to field-like conditions, we put 88 Australian volunteer firefighters through a multi-day firefighting simulation. Participants were required to perform real-world physical and cognitive tasks under conditions of elevated temperature and moderate sleep restriction. We aimed to examine changes in fatigue in an effort to determine the optimum objective and subjective measures. Objective and subjective tests were sensitive to fatigue outside laboratory conditions. The PVT was the most sensitive assay of objective fatigue, with the Samn-Perelli fatigue scale the most sensitive of the subjective measures. The Samn-Perilli fatigue scale correlated best with PVT performance, but explained a small amount of variance. Although the Samn-Perelli scale can be easily administered in the field, the wide range of individual variance limits its efficacy as a once-off assessment tool. Rather, fatigue measures should be applied as a component of a broader fatigue risk management system. Findings provide firefighting agencies, and other occupations involving physical work, guidance as to the most sensitive and specific measures for assessing fatigue in their personnel.

  10. Objectively measured sedentary behaviour and moderate and vigorous physical activity in different school subjects: a cross-sectional study

    OpenAIRE

    Mooses, Kerli; M?gi, Katrin; Riso, Eva-Maria; Kalma, Maarja; Kaasik, Priit; Kull, Merike

    2017-01-01

    Background Evidence shows the positive influence of moderate and vigorous physical activity (MVPA) and negative influence of sedentary time on health and academic achievement. Although schools can significantly contribute to overall physical activity, little is known about MVPA and sedentary behaviour in different school subjects in different grades. Methods Physical activity of 646 students from 18 schools (94 classes) and from three school stages (grades 1?9, aged 7?16) was measured with ac...

  11. Objectively measured sedentary behaviour and moderate and vigorous physical activity in different school subjects: a cross-sectional study

    OpenAIRE

    Kerli Mooses; Katrin Mägi; Eva-Maria Riso; Maarja Kalma; Priit Kaasik; Merike Kull

    2017-01-01

    Abstract Background Evidence shows the positive influence of moderate and vigorous physical activity (MVPA) and negative influence of sedentary time on health and academic achievement. Although schools can significantly contribute to overall physical activity, little is known about MVPA and sedentary behaviour in different school subjects in different grades. Methods Physical activity of 646 students from 18 schools (94 classes) and from three school stages (grades 1–9, aged 7–16) was measure...

  12. Characterization of Small Focal Renal Lesions: Diagnostic Accuracy with Single-Phase Contrast-enhanced Dual-Energy CT with Material Attenuation Analysis Compared with Conventional Attenuation Measurements.

    Science.gov (United States)

    Marin, Daniele; Davis, Drew; Roy Choudhury, Kingshuk; Patel, Bhavik; Gupta, Rajan T; Mileto, Achille; Nelson, Rendon C

    2017-09-01

    Purpose To determine whether single-phase contrast material-enhanced dual-energy material attenuation analysis improves the characterization of small (1-4 cm) renal lesions compared with conventional attenuation measurements by using histopathologic analysis and follow-up imaging as the clinical reference standards. Materials and Methods In this retrospective, HIPAA-compliant, institutional review board-approved study, 136 consecutive patients (95 men and 41 women; mean age, 54 years) with 144 renal lesions (111 benign, 33 malignant) measuring 1-4 cm underwent single-energy unenhanced and contrast-enhanced dual-energy computed tomography (CT) of the abdomen. For each renal lesion, attenuation measurements were obtained; attenuation change of greater than or equal to 15 HU was considered evidence of enhancement. Dual-energy attenuation measurements were also obtained by using iodine-water, water-iodine, calcium-water, and water-calcium material basis pairs. Mean lesion attenuation values and material densities were compared between benign and malignant renal lesions by using the two-sample t test. Diagnostic accuracy of attenuation measurements and dual-energy material densities was assessed and validated by using 10-fold cross-validation to limit the effect of optimistic bias. Results By using cross-validated optimal thresholds at 100% sensitivity, iodine-water material attenuation images significantly improved specificity for differentiating between benign and malignant renal lesions compared with conventional enhancement measurements (93% [103 of 111]; 95% confidence interval: 86%, 97%; vs 81% [90 of 111]; 95% confidence interval: 73%, 88%) (P = .02). Sensitivity with iodine-water and calcium-water material attenuation images was also higher than that with conventional enhancement measurements, although the difference was not statistically significant. Conclusion Contrast-enhanced dual-energy CT with material attenuation analysis improves specificity for

  13. Measuring Treatment Outcomes in Comorbid Insomnia and Fibromyalgia: Concordance of Subjective and Objective Assessments.

    Science.gov (United States)

    Mundt, Jennifer M; Crew, Earl C; Krietsch, Kendra; Roth, Alicia J; Vatthauer, Karlyn; Robinson, Michael E; Staud, Roland; Berry, Richard B; McCrae, Christina S

    2016-02-01

    In insomnia, actigraphy tends to underestimate wake time compared to diaries and PSG. When chronic pain co-occurs with insomnia, sleep may be more fragmented, including more movement and arousals. However, individuals may not be consciously aware of these arousals. We examined the baseline concordance of diaries, actigraphy, and PSG as well as the ability of each assessment method to detect changes in sleep following cognitive behavioral therapy for insomnia (CBT-I). Adults with insomnia and fibromyalgia (n = 113) were randomized to CBT-I, CBT for pain, or waitlist control. At baseline and posttreatment, participants completed one night of PSG and two weeks of diaries/actigraphy. At baseline, objective measures estimated lower SOL, higher TST, and higher SE than diaries (ps treatment-related changes. PSG values did not change significantly for any sleep parameters. However, diaries showed improvements in SOL, WASO, and SE, and actigraphy also detected the WASO and SE improvements (ps insomnia. However, actigraphy showed greater sensitivity to treatment-related changes than PSG; PSG failed to detect any improvements, but actigraphy demonstrated changes in WASO and SE, which were also found with diaries. In comorbid insomnia/fibromyalgia, actigraphy may therefore have utility in measuring treatment outcomes. © 2015 American Academy of Sleep Medicine.

  14. Measurements of pericardial adipose tissue using contrast enhanced cardiac multidetector computed tomography—comparison with cardiac magnetic resonance imaging

    DEFF Research Database (Denmark)

    Elming, Marie Bayer; Lønborg, Jacob; Rasmussen, Thomas

    2013-01-01

    Recent studies have suggested that pericardial adipose tissue (PAT) located in close vicinity to the epicardial coronary arteries may play a role in the development of coronary artery disease. PAT has primarily been measured with cardiac magnetic resonance imaging (CMRI) or with non...... can be measured on standard coronary CT angiography images with a reasonable degree of accuracy when compared to CMRI....

  15. Food Addiction: definition, measurement and prevalence in healthy subjects and in patients with eating disorders.

    Science.gov (United States)

    Imperatori, Claudio; Fabbricatore, Mariantonietta; Vumbaca, Viviana; Innamorati, Marco; Contardi, Anna; Farina, Benedetto

    2016-01-01

    The construct of “Food Addiction” (FA) has been introduced in the last decades to better understand abnormal eating patterns in obese and overweight people and in patients with Eating Disorders (EDs). Despite a substantial parallelism between drug addiction and FA, there is still no agreement in considering FA an independent ED or a useful convincing concept. Therefore, the purpose of this review is to aggregate available data, in order to increase knowledge about: 1) definition, measurement and general features of FA; 2) prevalence of FA in clinical and non-clinical samples. Available data suggest that FA seems to be a transnosografic construct and exists in all EDs, with higher prevalence in Bulimia Nervosa. Although the discussion on the autonomous diagnosis of FA within EDs remains open, studies have reported that comorbidity between FA and other EDs is associated with worse clinical conditions and symptoms, justifying, as a result, the usefulness of assessing and treating this condition.

  16. Effector cell mediated cytotoxicity measured by intracellular Granzyme B release in HIV infected subjects

    Directory of Open Access Journals (Sweden)

    Mahajan Supriya D.

    2003-01-01

    Full Text Available CD8+ cytotoxic T lymphocyte (CTL activity is currently believed to be one of the key immunologic mechanisms responsible for the prevention or attenuation of HIV-1 infection. The induction of CD8+ T cell activation may also result in the production of soluble or non-classical lytic factors that are associated with protection from infection or slower disease progression. Traditionally, CD8+ CTL responses have been measured by the classic chromium release assay, monitoring the ability of T cells (Effector cells to lyse radiolabelled HLA – matched “target cells” that express the appropriate antigen-MHC complex. This method is not only labor intensive, semi quantitative assay at best, but also needs fresh, non-cryopreserved cells. Recently, cytokine specific ELISPOT assays or tetrameric MHC-I/ peptide complexes have utilized to directly quantitate circulating CD8+ effector cells, and these assays are more sensitive, quantitative and reproducible than the traditional CTL lysis assay and can also be performed on cryopreserved cells. Although these are reproducible assays for the assessment of soluble antiviral activity secreted by activated T cell populations they can be extremely expensive to perform. We have used FACS Analysis to measure Granzyme B release as a function of cell mediated cytotoxicity. This method helps quantitate the CTL activity and also identifies the phenotype of the cells elucidating this immune response. The method described not only monitors immunological response but also is also simple to perform, precise and extremely time efficient and is ideal for screening a large number of samples.

  17. Optimization of the method for assessment of brain perfusion in humans using contrast-enhanced reflectometry: multidistance time-resolved measurements

    Science.gov (United States)

    Milej, Daniel; Janusek, Dariusz; Gerega, Anna; Wojtkiewicz, Stanislaw; Sawosz, Piotr; Treszczanowicz, Joanna; Weigl, Wojciech; Liebert, Adam

    2015-10-01

    The aim of the study was to determine optimal measurement conditions for assessment of brain perfusion with the use of optical contrast agent and time-resolved diffuse reflectometry in the near-infrared wavelength range. The source-detector separation at which the distribution of time of flights (DTOF) of photons provided useful information on the inflow of the contrast agent to the intracerebral brain tissue compartments was determined. Series of Monte Carlo simulations was performed in which the inflow and washout of the dye in extra- and intracerebral tissue compartments was modeled and the DTOFs were obtained at different source-detector separations. Furthermore, tests on diffuse phantoms were carried out using a time-resolved setup allowing the measurement of DTOFs at 16 source-detector separations. Finally, the setup was applied in experiments carried out on the heads of adult volunteers during intravenous injection of indocyanine green. Analysis of statistical moments of the measured DTOFs showed that the source-detector separation of 6 cm is recommended for monitoring of inflow of optical contrast to the intracerebral brain tissue compartments with the use of continuous wave reflectometry, whereas the separation of 4 cm is enough when the higher-order moments of DTOFs are available.

  18. Effect of inspiration on airway dimensions measured in maximal inspiration CT images of subjects without airflow limitation

    Energy Technology Data Exchange (ETDEWEB)

    Petersen, Jens; Raket, Lars Lau; Nielsen, Mads [University of Copenhagen, Department of Computer Science, Copenhagen (Denmark); Wille, Mathilde M.W.; Dirksen, Asger [University of Copenhagen, Department of Respiratory Medicine, Gentofte Hospital, Hellerup (Denmark); Feragen, Aasa [University of Copenhagen, Department of Computer Science, Copenhagen (Denmark); Max Planck Institute for Intelligent Systems and Max Planck Institute for Developmental Biology, Tuebingen (Germany); Pedersen, Jesper H. [Rigshospitalet, University Hospital of Copenhagen, Department of Cardio-Thoracic Surgery RT, Copenhagen (Denmark); Bruijne, Marleen de [University of Copenhagen, Department of Computer Science, Copenhagen (Denmark); Erasmus MC Rotterdam, Departments of Medical Informatics and Radiology, Rotterdam (Netherlands)

    2014-09-15

    To study the effect of inspiration on airway dimensions measured in voluntary inspiration breath-hold examinations. 961 subjects with normal spirometry were selected from the Danish Lung Cancer Screening Trial. Subjects were examined annually for five years with low-dose CT. Automated software was utilized to segment lungs and airways, identify segmental bronchi, and match airway branches in all images of the same subject. Inspiration level was defined as segmented total lung volume (TLV) divided by predicted total lung capacity (pTLC). Mixed-effects models were used to predict relative change in lumen diameter (ALD) and wall thickness (AWT) in airways of generation 0 (trachea) to 7 and segmental bronchi (R1-R10 and L1-L10) from relative changes in inspiration level. Relative changes in ALD were related to relative changes in TLV/pTLC, and this distensibility increased with generation (p < 0.001). Relative changes in AWT were inversely related to relative changes in TLV/pTLC in generation 3-7 (p < 0.001). Segmental bronchi were widely dispersed in terms of ALD (5.7 ± 0.7 mm), AWT (0.86 ± 0.07 mm), and distensibility (23.5 ± 7.7 %). Subjects who inspire more deeply prior to imaging have larger ALD and smaller AWT. This effect is more pronounced in higher-generation airways. Therefore, adjustment of inspiration level is necessary to accurately assess airway dimensions. (orig.)

  19. Subject-enabled analytics model on measurement statistics in health risk expert system for public health informatics.

    Science.gov (United States)

    Chung, Chi-Jung; Kuo, Yu-Chen; Hsieh, Yun-Yu; Li, Tsai-Chung; Lin, Cheng-Chieh; Liang, Wen-Miin; Liao, Li-Na; Li, Chia-Ing; Lin, Hsueh-Chun

    2017-11-01

    This study applied open source technology to establish a subject-enabled analytics model that can enhance measurement statistics of case studies with the public health data in cloud computing. The infrastructure of the proposed model comprises three domains: 1) the health measurement data warehouse (HMDW) for the case study repository, 2) the self-developed modules of online health risk information statistics (HRIStat) for cloud computing, and 3) the prototype of a Web-based process automation system in statistics (PASIS) for the health risk assessment of case studies with subject-enabled evaluation. The system design employed freeware including Java applications, MySQL, and R packages to drive a health risk expert system (HRES). In the design, the HRIStat modules enforce the typical analytics methods for biomedical statistics, and the PASIS interfaces enable process automation of the HRES for cloud computing. The Web-based model supports both modes, step-by-step analysis and auto-computing process, respectively for preliminary evaluation and real time computation. The proposed model was evaluated by computing prior researches in relation to the epidemiological measurement of diseases that were caused by either heavy metal exposures in the environment or clinical complications in hospital. The simulation validity was approved by the commercial statistics software. The model was installed in a stand-alone computer and in a cloud-server workstation to verify computing performance for a data amount of more than 230K sets. Both setups reached efficiency of about 105 sets per second. The Web-based PASIS interface can be used for cloud computing, and the HRIStat module can be flexibly expanded with advanced subjects for measurement statistics. The analytics procedure of the HRES prototype is capable of providing assessment criteria prior to estimating the potential risk to public health. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. A Comparison of Sap Flow Measurements and Potometry in Two Tropical Lowland Tree Species with Contrasting Wood Properties

    Directory of Open Access Journals (Sweden)

    Marco V Gutiérrez

    2006-03-01

    Full Text Available We evaluated the performance of the Heat Dissipation Technique (HDT to measure sap flow in whole trees by comparison with potometric water uptake. Two tropical lowland species, Ochroma lagopus (balsa, a pioneer species with light wood and Hyeronima alchorneoides (pilón, a late-successional species with hard wood were examined. Diurnal courses of sap flow measured with the HDT showed good agreement with potometry. At the low sap flow rates (below 1 Kg h-1 occurring during nocturnal recharge HDT consistently underestimated sap flow rates. This resulted in the failure of the current version of the HDT to measure nocturnal water uptake, an important component of the water budget of at least one of the two species examined. Rev. Biol. Trop. 54(1: 73-81. Epub 2006 Mar 31.

  1. Comparison of optic area measurement using fundus photography and optical coherence tomography between optic nerve head drusen and control subjects.

    Science.gov (United States)

    Flores-Rodríguez, Patricia; Gili, Pablo; Martín-Ríos, María Dolores; Grifol-Clar, Eulalia

    2013-03-01

    To compare optic disc area measurement between optic nerve head drusen (ONHD) and control subjects using fundus photography, time-domain optical coherence tomography (TD-OCT) and spectral-domain optical coherence tomography (SD-OCT). We also made a comparison between each of the three techniques. We performed our study on 66 eyes (66 patients) with ONHD and 70 healthy control subjects (70 controls) with colour ocular fundus photography at 20º (Zeiss FF 450 IR plus), TD-OCT (Stratus OCT) with the Fast Optic Disc protocol and SD-OCT (Cirrus OCT) with the Optic Disc Cube 200 × 200 protocol for measurement of the optic disc area. The measurements were made by two observers and in each measurement a correction of the image magnification factor was performed. Measurement comparison using the Student's t-test/Mann-Whitney U test, the intraclass correlation coefficient, Pearson/Spearman rank correlation coefficient and the Bland-Altman plot was performed in the statistical analysis. Mean and standard deviation (SD) of the optic disc area in ONHD and in controls was 2.38 (0.54) mm(2) and 2.54 (0.42) mm(2), respectively with fundus photography; 2.01 (0.56) mm(2) and 1.66 (0.37) mm(2), respectively with TD-OCT, and 2.03 (0.49) mm(2) and 1.75 (0.38) mm(2), respectively with SD-OCT. In ONHD and controls, repeatability of optic disc area measurement was excellent with fundus photography and optical coherence tomography (TD-OCT and SD-OCT), but with a low degree of agreement between both techniques. Optic disc area measurement is smaller in ONHD compared to healthy subjects with fundus photography, unlike time-domain and spectral-domain optical coherence tomography in which the reverse is true. Both techniques offer good repeatability, but a low degree of correlation and agreement, which means that optic disc area measurement is not interchangeable or comparable between techniques. Ophthalmic & Physiological Optics © 2013 The College of Optometrists.

  2. Analysis of misclassified correlated binary data using a multivariate probit model when covariates are subject to measurement error.

    Science.gov (United States)

    Roy, Surupa; Banerjee, Tathagata

    2009-06-01

    A multivariate probit model for correlated binary responses given the predictors of interest has been considered. Some of the responses are subject to classification errors and hence are not directly observable. Also measurements on some of the predictors are not available; instead the measurements on its surrogate are available. However, the conditional distribution of the unobservable predictors given the surrogate is completely specified. Models are proposed taking into account either or both of these sources of errors. Likelihood-based methodologies are proposed to fit these models. To ascertain the effect of ignoring classification errors and/or measurement error on the estimates of the regression and correlation parameters, a sensitivity study is carried out through simulation. Finally, the proposed methodology is illustrated through an example.

  3. Subjective Cognitive Decline in Older Adults: An Overview of Self-Report Measures Used Across 19 International Research Studies

    Science.gov (United States)

    Rabin, Laura A.; Smart, Colette M.; Crane, Paul K.; Amariglio, Rebecca E.; Berman, Lorin M.; Boada, Mercè; Buckley, Rachel F.; Chételat, Gaël; Dubois, Bruno; Ellis, Kathryn A.; Gifford, Katherine A.; Jefferson, Angela L.; Jessen, Frank; Katz, Mindy J.; Lipton, Richard B.; Luck, Tobias; Maruff, Paul; Mielke, Michelle M.; Molinuevo, José Luis; Naeem, Farnia; Perrotin, Audrey; Petersen, Ronald C.; Rami, Lorena; Reisberg, Barry; Rentz, Dorene M.; Riedel-Heller, Steffi G.; Risacher, Shannon L.; Rodriguez, Octavio; Sachdev, Perminder S.; Saykin, Andrew J.; Slavin, Melissa J.; Snitz, Beth E.; Sperling, Reisa A.; Tandetnik, Caroline; van der Flier, Wiesje M.; Wagner, Michael; Wolfsgruber, Steffen; Sikkes, Sietske A.M.

    2015-01-01

    Research increasingly suggests that subjective cognitive decline (SCD) in older adults, in the absence of objective cognitive dysfunction or depression, may be a harbinger of non-normative cognitive decline and eventual progression to dementia. Little is known, however, about the key features of self-report measures currently used to assess SCD. The Subjective Cognitive Decline Initiative (SCD-I) Working Group is an international consortium established to develop a conceptual framework and research criteria for SCD (Jessen et al., 2014, Alzheimers Dement 10, 844–852). In the current study we systematically compared cognitive self-report items used by 19 SCD-I Working Group studies, representing 8 countries and 5 languages. We identified 34 self-report measures comprising 640 cognitive self-report items. There was little overlap among measures—approximately 75% of measures were used by only one study. Wide variation existed in response options and item content. Items pertaining to the memory domain predominated, accounting for about 60% of items surveyed, followed by executive function and attention, with 16% and 11% of the items, respectively. Items relating to memory for the names of people and the placement of common objects were represented on the greatest percentage of measures (56% each). Working group members reported that instrument selection decisions were often based on practical considerations beyond the study of SCD specifically, such as availability and brevity of measures. Results document the heterogeneity of approaches across studies to the emerging construct of SCD. We offer preliminary recommendations for instrument selection and future research directions including identifying items and measure formats associated with important clinical outcomes. PMID:26402085

  4. Significantly Reduced Blood Pressure Measurement Variability for Both Normotensive and Hypertensive Subjects: Effect of Polynomial Curve Fitting of Oscillometric Pulses.

    Science.gov (United States)

    Yang, Fangwei; Chen, Fei; Zhu, Mingping; Chen, Aiqing; Zheng, Dingchang

    2017-01-01

    This study aimed to compare within-subject blood pressure (BP) variabilities from different measurement techniques. Cuff pressures from three repeated BP measurements were obtained from 30 normotensive and 30 hypertensive subjects. Automatic BPs were determined from the pulses with normalised peak amplitude larger than a threshold (0.5 for SBP, 0.7 for DBP, and 1.0 for MAP). They were also determined from cuff pressures associated with the above thresholds on a fitted curve polynomial curve of the oscillometric pulse peaks. Finally, the standard deviation (SD) of three repeats and its coefficient of variability (CV) were compared between the two automatic techniques. For the normotensive group, polynomial curve fitting significantly reduced SD of repeats from 3.6 to 2.5 mmHg for SBP and from 3.7 to 2.1 mmHg for MAP and reduced CV from 3.0% to 2.2% for SBP and from 4.3% to 2.4% for MAP (all P oscillometric pulses had the ability to reduce automatic BP measurement variability.

  5. Associated Factors of Atrophic Gastritis Diagnosed by Double-Contrast Upper Gastrointestinal Barium X-Ray Radiography: A Cross-Sectional Study Analyzing 6,901 Healthy Subjects in Japan

    Science.gov (United States)

    Yamamichi, Nobutake; Hirano, Chigaya; Shimamoto, Takeshi; Minatsuki, Chihiro; Takahashi, Yu; Nakayama, Chiemi; Matsuda, Rie; Fujishiro, Mitsuhiro; Konno-Shimizu, Maki; Kato, Jun; Kodashima, Shinya; Ono, Satoshi; Niimi, Keiko; Mochizuki, Satoshi; Tsuji, Yosuke; Sakaguchi, Yoshiki; Asada-Hirayama, Itsuko; Takeuchi, Chihiro; Yakabi, Seiichi; Kakimoto, Hikaru; Wada, Ryoichi; Mitsushima, Toru; Ichinose, Masao; Koike, Kazuhiko

    2014-01-01

    Background Double-contrast upper gastrointestinal barium X-ray radiography (UGI-XR) is one of the most widely conducted gastric cancer screening methods. It has been executed to find gastric cancer, but has not been usually executed to detect premalignant atrophic mucosa of stomach. To understand the meaning of UGI-XR-based atrophic gastritis, we analyzed its association with several causative factors including Helicobacter pylori (HP) infection. Methods We evaluated 6,901 healthy adults in Japan. UGI-XR-based atrophic gastritis was diagnosed based on the irregular shape of areae gastricae and its expansion in the stomach. Results Of the 6,433 subjects with no history of HP eradication and free from gastric acid suppressants, 1,936 were diagnosed as UGI-XR-based atrophic gastritis (mild: 234, moderate: 822, severe: 880). These were univariately associated with serum HP IgG and serum pepsinogen I/II ratio with statistical significance. The multiple logistic analysis calculating standardized coefficients (β) and odds ratio (OR) demonstrated that serum HP IgG (β = 1.499, OR = 4.48), current smoking (β = 0.526, OR = 1.69), age (β = 0.401, OR = 1.49), low serum pepsinogen I/II ratio (β = 0.339, OR = 1.40), and male gender (β = 0.306, OR = 1.36) showed significant positive association with UGI-XR-based atrophic gastritis whereas drinking and body mass index did not. Among the age/sex/smoking/drinking-matched 227 pairs derived from chronically HP-infected and successfully HP-eradicated subjects, UGI-XR-based atrophic gastritis was detected in 99.1% of the former but in only 59.5% of the latter subjects (pgastritis was detected in 13 of 14 HP-positive proton pump inhibitor users (92.9%) and 33 of 34 HP-positive histamine H2-receptor antagonist users (97.1%), which are not significantly different from gastric acid suppressant-free subjects. Conclusions The presence of UGI-XR-based atrophic gastritis is positively associated with

  6. Automation of Methods for the Subjective Measuring of Factors in the Operation of Automated Information Systems by Means of VBA

    Directory of Open Access Journals (Sweden)

    Lyudmila V. Gorbatova

    2015-01-01

    Full Text Available This article describes the process of assessing the effectiveness of the operation of automated information systems in colleges using the method of pairwise comparison and discusses numerical representations used with the above method. The author lists methods for the subjective measuring of the effective operation of automated information systems. The article proposes a way to automate the methods that makes it possible to simplify performing calculations and reduce the amount of time it takes to determine the outcome of a specific task. The author provides an algorithm with the results of work carried out.

  7. Evaluation of changes in birefringence for samples subjected to various stress sources measured with polarization-sensitive OCT

    Science.gov (United States)

    Karnowski, Karol; Li, Qingyun; Villiger, Martin; Sampson, David D.

    2017-04-01

    Polarization-sensitive OCT (PS-OCT) has proven useful in determining the stress-induced birefringence of non-biological materials, but such utility in biological tissues subjected to stress has not been well studied yet. To study stress-induced birefringence of biological tissues, we use a swept-source PS-OCT system with passively depth-encoded, orthogonal polarization states in the illumination path and polarization-diversity detection and a Mueller formalism in post-processing. We present measurements of stress-induced changes in the birefringence of non-biological and biological samples that provide useful benchmarks in further assessing the utility of this approach.

  8. Measurement of effective alveolar carbon dioxide tension during spontaneous breathing in normal subjects and patients with chronic airways obstruction.

    OpenAIRE

    Jordanoglou, J.; Koulouris, N; Kyroussis, D.; Rapakoulias, P.; Vassalos, P.; Madianos, J.

    1995-01-01

    BACKGROUND--The measurement of effective alveolar carbon dioxide tension (PA-CO2eff) is still a matter of debate. It has, however, become common practice to use arterial instead of alveolar CO2 tension for computing alveolar oxygen tension (PAO2) and physiological dead space, not only in normal subjects but also in patients. The purpose of this study was to estimate alveolar CO2 tension during spontaneous breathing with a new bedside technique which is simple and non-invasive, and to compare ...

  9. Correction with blood T1 is essential when measuring post-contrast myocardial T1 value in patients with acute myocardial infarction.

    Science.gov (United States)

    Choi, Eui-Young; Hwang, Sung Ho; Yoon, Young Won; Park, Chul Hwan; Paek, Mun Young; Greiser, Andreas; Chung, Hyemoon; Yoon, Ji-Hyun; Kim, Jong-Youn; Min, Pil-Ki; Lee, Byoung Kwon; Hong, Bum-Kee; Rim, Se-Joong; Kwon, Hyuck Moon; Kim, Tae Hoon

    2013-01-19

    Post-contrast T1 mapping by modified Look-Locker inversion recovery (MOLLI) sequence has been introduced as a promising means to assess an expansion of the extra-cellular space. However, T1 value in the myocardium can be affected by scanning time after bolus contrast injection. In this study, we investigated the changes of the T1 values according to multiple slicing over scanning time at 15 minutes after contrast injection and usefulness of blood T1 correction. Eighteen reperfused acute myocardial infarction (AMI) patients, 13 cardiomyopathy patients and 8 healthy volunteers underwent cardiovascular magnetic resonance with 15 minute-post contrast MOLLI to generate T1 maps. In 10 cardiomyopathy cases, pre- and post-contrast MOLLI techniques were performed to generate extracellular volume fraction (Ve). Six slices of T1 maps according to the left ventricular (LV) short axis, from apex to base, were consecutively obtained. Each T1 value was measured in the whole myocardium, infarcted myocardium, non-infarcted myocardium and LV blood cavity. The mean T1 value of infarcted myocardium was significantly lower than that of non-infarcted myocardium (425.4 ± 68.1 ms vs. 540.5 ± 88.0 ms, respectively, p infarcted myocardium increased significantly from apex to base (from 523.1 ± 99.5 ms to 561.1 ± 81.1 ms, p = 0.001), and were accompanied by a similar increase in blood T1 value in LV cavity (from 442.1 ± 120.7 ms to 456.8 ± 97.5 ms, p myocardial T1 values, however, were adjusted by the blood T1 values, they were consistent throughout the slices from apex to base (from 1.17 ± 0.18 to 1.25 ± 0.13, p > 0.05). The Ve did not show significant differences from apical to basal slices. Post-contrast myocardial T1 corrected by blood T1 or Ve, provide more stable measurement of degree of fibrosis in non-infarcted myocardium in short- axis multiple slicing.

  10. Caffeine can decrease subjective energy depending on the vehicle with which it is consumed and when it is measured.

    Science.gov (United States)

    Young, H A; Benton, D

    2013-07-01

    Energy drinks contain glucose and caffeine, although in the longer term both adversely influence blood glucose homeostasis, with the unconsidered potential to have adverse consequences for cognition and mood. The objective of this study was to consider the influence on interstitial glucose levels, mood and cognition of drinks differing in their caffeine content and glycaemic load. Ninety minutes after a standard breakfast, a yoghurt-, glucose- or water-based drink, with or without 80 mg of caffeine, was consumed. The consumption of caffeine negatively influenced glucose homeostasis: that is, irrespective of the vehicle, caffeine consumption resulted in elevated levels of blood glucose throughout the study. Thirty minutes after consuming caffeine and water, rather than water alone, greater subjective energy was reported. However, after 90 and 150 min, caffeine administered in water increased tiredness, hostility and confusion. In contrast, combining caffeine with a yoghurt-based drink increased energy, agreeableness and clearheadedness later in the morning. There were no effects of caffeine on ratings of mood when it was taken with glucose. Caffeine, irrespective of vehicle, resulted in better memory, quicker reaction times in the choice reaction time test and the working memory task, and better and quicker responses with the vigilance task. Further research should consider how caffeine interacts with macronutrients and the timescale over which such effects occur.

  11. Measuring the subjective: revisiting the psychometric properties of three rating scales that assess the acute effects of hallucinogens.

    Science.gov (United States)

    Bouso, José Carlos; Pedrero-Pérez, Eduardo José; Gandy, Sam; Alcázar-Córcoles, Miguel Ángel

    2016-09-01

    In the present study we explored the psychometric properties of three widely used questionnaires to assess the subjective effects of hallucinogens: the Hallucinogen Rating Scale (HRS), the Mystical Experience Questionnaire (MEQ), and the Addiction Research Center Inventory (ARCI). These three questionnaires were administered to a sample of 158 subjects (100 men) after taking ayahuasca, a hallucinogen whose main active component is N,N-dimethyltryptamine (DMT). A confirmatory factorial study was conducted to check the adjustment of previous data obtained via theoretical proposals. When this was not possible, we used an exploratory factor analysis without restrictions, based on tetrachoric and polychoric matrices and correlations. Our results sparsely match the theoretical proposals of the authors, perhaps because previous studies have not always employed psychometric methods appropriate to the data obtained. However, these data should be considered preliminary, pending larger samples to confirm or reject the proposed structures obtained. It is crucial that instruments of sufficiently precise measurement are utilized to make sense of the information obtained in the study of the subjective effects of psychedelic drugs. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  12. Simultaneous measures of kinematics and fMRI: relation between movement parameters and activation maps in healthy subjects

    Science.gov (United States)

    Gandolla, M.; Casellato, C.; Ferrante, S.; Ferrigno, G.; Baselli, G.; Molteni, F.; Martegani, A.; Frattini, T.; Pedrocchi, A.

    2010-03-01

    The objective of this study was to identify on healthy subjects the correlation between motor performances and brain activation maps, by the simultaneous use of functional magnetic resonance imaging (fMRI) and optoelectronic motion analysis system. The specific goal was to individuate how amplitude affects the related cerebral flow maps in active, passive and electrical stimulated (FES) movements. Ankle DorsiFlexion (ADF) was chosen as analyzed task because of its importance in the gait cycle. Firstly FES compatibility with fMRI images acquisition was assessed, both for the safety of the subject and of the device, and for mutual disturbances evaluation. We identified the experimental protocol so as to optimize the measured cerebral maps and the repeatability of the results. Intra-subject analysis of movement parameters along with brain activation mapping was performed. First level analysis to compare different execution modalities have been studied and preliminary qualitative results are reported. The long term application is the exploitation of the combined system in the evaluation of neurological patients where the definition of the motor tasks could be only partially accomplished depending on the patient residual functionality.

  13. Objectively measured sedentary behaviour and moderate and vigorous physical activity in different school subjects: a cross-sectional study

    Directory of Open Access Journals (Sweden)

    Kerli Mooses

    2017-01-01

    Full Text Available Abstract Background Evidence shows the positive influence of moderate and vigorous physical activity (MVPA and negative influence of sedentary time on health and academic achievement. Although schools can significantly contribute to overall physical activity, little is known about MVPA and sedentary behaviour in different school subjects in different grades. Methods Physical activity of 646 students from 18 schools (94 classes and from three school stages (grades 1–9, aged 7–16 was measured with accelerometry for 5 school days. Time and proportion of MVPA and sedentary time, also average sedentary bout length was calculated for native language (Estonian, mathematics, science, foreign language, music and crafts lessons. Results A total of 6363 lessons were measured, with lesson duration of 45 min. The average lesson time MVPA remained below 2.2 min in all school stages and in all subjects. Students in grades 4–6 had greatest decline in the proportion of lesson time MVPA in science (β = −1.9, 95%CI −3.1– -0.6 and music (−1.2, −2.1– -0.4 and in grades 7–9 in music (−1.7, −3.1– -0.3 lessons compared to grades 1–3. In grades 1–3 students spent on average 76% of lesson time (34.0 ± 7.0 min as sedentary, whereas in grades 7–9 the average proportion of sedentary time was 87% (38.9 ± 5.7 min. An average sedentary bout length increased from 13 min in grades 1–3 to 20 min in grades 7–9. An increase in sedentary bout length from grades 1–3 compared to grades 7–9 was present in most subjects, except crafts, with smallest increase in foreign language (6 min, 3.5–8.9 and greatest in music lessons (16.6 min, 11.9–21.3. Lessons with prolonged sedentary bouts formed a maximum 36% of all lessons in grades 1–3 and 73% in grades 7–9. Conclusion The long sedentary time, bout length and low MVPA in most subjects were unfavourable in respect of both health and academic achievement. Significantly

  14. Objectively measured sedentary behaviour and moderate and vigorous physical activity in different school subjects: a cross-sectional study.

    Science.gov (United States)

    Mooses, Kerli; Mägi, Katrin; Riso, Eva-Maria; Kalma, Maarja; Kaasik, Priit; Kull, Merike

    2017-01-23

    Evidence shows the positive influence of moderate and vigorous physical activity (MVPA) and negative influence of sedentary time on health and academic achievement. Although schools can significantly contribute to overall physical activity, little is known about MVPA and sedentary behaviour in different school subjects in different grades. Physical activity of 646 students from 18 schools (94 classes) and from three school stages (grades 1-9, aged 7-16) was measured with accelerometry for 5 school days. Time and proportion of MVPA and sedentary time, also average sedentary bout length was calculated for native language (Estonian), mathematics, science, foreign language, music and crafts lessons. A total of 6363 lessons were measured, with lesson duration of 45 min. The average lesson time MVPA remained below 2.2 min in all school stages and in all subjects. Students in grades 4-6 had greatest decline in the proportion of lesson time MVPA in science (β = -1.9, 95%CI -3.1- -0.6) and music (-1.2, -2.1- -0.4) and in grades 7-9 in music (-1.7, -3.1- -0.3) lessons compared to grades 1-3. In grades 1-3 students spent on average 76% of lesson time (34.0 ± 7.0 min) as sedentary, whereas in grades 7-9 the average proportion of sedentary time was 87% (38.9 ± 5.7 min). An average sedentary bout length increased from 13 min in grades 1-3 to 20 min in grades 7-9. An increase in sedentary bout length from grades 1-3 compared to grades 7-9 was present in most subjects, except crafts, with smallest increase in foreign language (6 min, 3.5-8.9) and greatest in music lessons (16.6 min, 11.9-21.3). Lessons with prolonged sedentary bouts formed a maximum 36% of all lessons in grades 1-3 and 73% in grades 7-9. The long sedentary time, bout length and low MVPA in most subjects were unfavourable in respect of both health and academic achievement. Significantly increasing sedentary time and sedentary bout length in older school stages highlights the need for

  15. Contrast-Enhanced CMR Overestimates Early Myocardial Infarct Size: Mechanistic Insights Using ECV Measurements on Day 1 and Day 7.

    Science.gov (United States)

    Jablonowski, Robert; Engblom, Henrik; Kanski, Mikael; Nordlund, David; Koul, Sasha; van der Pals, Jesper; Englund, Elisabet; Heiberg, Einar; Erlinge, David; Carlsson, Marcus; Arheden, Håkan

    2015-12-01

    This study aimed to investigate whether an overestimation of infarct size on cardiac magnetic resonance (CMR) versus triphenyltetrazolium chloride (TTC) exists acutely and whether it remains after 7 days in an experimental pig model and to elucidate possible mechanisms. Overestimation of infarct size (IS) on late gadolinium enhancement CMR early after acute myocardial infarction has been debated. Pigs were subjected to 40 min of left anterior descending artery occlusion and 6 h (n = 9) or 7 days (n = 9) reperfusion. IS by in vivo and ex vivo CMR was compared with TTC staining. Extracellular volume (ECV) was obtained from biopsies using technetium 99m diethylenetriamine pentaacetic acid (99mTc-DTPA) and light microscopy. TTC slices were rescanned on CMR enabling slice-by-slice comparison. IS did not differ between in vivo and ex vivo CMR (p = 0.77). IS was overestimated by 27.3% with ex vivo CMR compared with TTC (p = 0.008) acutely with no significant difference at 7 days (p = 0.39). Slice-by-slice comparison showed similar results. A significant decrease in ECV was seen in biopsies of myocardium at risk (MaR) close to the infarct (sometimes referred to as the peri-infarction zone) over 7 days (48.3 ± 4.4% vs. 29.2 ± 2.4%; p = 0.0025). The ECV differed between biopsies of MaR close to the infarct and the rest of the salvaged MaR acutely (48.3 ± 4.4% vs. 32.4 ± 3.2%; p = 0.013) but not at 7 days (29.2 ± 2.4% vs 25.7 ± 1.4%; p = 0.23). CMR overestimates IS compared with TTC acutely but not at 7 days. This difference may be explained by higher ECV in MaR closest to the infarct acutely that decreases during 7 days to the same level as the rest of the salvaged MaR. The increased ECV in the MaR closest to the infarct day 1 could be due to severe edema or an admixture of infarcted and salvaged myocardium (partial volume) or both. Nonetheless, this could not be reproduced at 7 days. These results have implications for timing of magnetic resonance infarct imaging

  16. Lack of agreement between objective and subjective measures in the evaluation of masticatory function: A preliminary study.

    Science.gov (United States)

    Pedroni-Pereira, Aline; Marquezin, Maria Carolina Salomé; Araujo, Darlle Santos; Pereira, Luciano José; Bommarito, Silvana; Castelo, Paula Midori

    2018-02-01

    The evaluation of mastication is important to understand the masticatory behavior and diagnose feeding difficulties. The objective of this preliminary study was to verify if there is agreement between objective and subjective validated methods of chewing evaluation in a convenience sample which consisted of 32 adolescents (mean 15.5years), complete permanent dentition and free of tooth decay. The Quality of Masticatory Function Questionnaire with the Food-Mastication, Habits, Meat, Fruit and Vegetables domains was used in the subjective evaluation. The objective aspects consisted of maximum bite force (BF) and masticatory performance (MP) by mastication of cubes of test-material and sieving to determine the median particle size (X50) and distribution in the sieves ("b"), and by the colorimetric method using colorchangeable chewing gum. Data were submitted to exploratory analysis, normality test and correlation tests (Pearson/Spearman). The correlation between BF and X50 (r=-0.43; p=0.02) and between BF and MP chewing gum (r=0.53; p=0.002) was significant with large effect size. The MP evaluated by chewing gum correlated with X50 (r=-0.34; p=0.055), but not with "b" (r=-0.06; p=0.73), while "b" correlated only with X50 (r=0.52, p=0.002). No significant correlation was observed between the objective measures and the total score of the subjective evaluation; only a negative correlation was observed between "b" and Meat domain (r=-0.40; p=0.023). The objective methods showed moderate correlation with each other and no agreement between the objective and subjective methods was observed in this sample of healthy adolescents, emphasizing the importance of both aspects in the evaluation of masticatory function. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. Frequency-domain photon migration measurements of normal and malignant tissue optical properties in a human subject

    Energy Technology Data Exchange (ETDEWEB)

    Fishkin, J.B.; Coquoz, O.; Anderson, E.R.; Brenner, M.; Tromberg, B.J. [Beckman Laser Institute and Medical Clinic, University of California at Irvine, 1002 Health Sciences Road East, Irvine, California 92612 (United States)]|[EA Photonics, 2515 Fisk Lane, Redondo Beach, California 90278 (United States)

    1997-01-01

    A 1-GHz multifrequency, multiwavelength frequency-domain photon migration instrument is used to measure quantitatively the optical absorption ({mu}{sub a}) and effective optical scattering ({mu}{sub s}{sup {prime}}) of normal and malignant tissues in a human subject. Large ellipsoidal ({approximately}10-cm major axis, {approximately}6-cm minor axes) subcutaneous malignant lesions were compared with adjacent normal sites in the abdomen and back. Absorption coefficients recorded at 674, 811, 849, and 956 nm were used to calculate tissue hemoglobin concentration (oxyhemoglobin, deoxyhemoglobin, and total), water concentration, hemoglobin oxygen saturation, and blood volume fraction {ital in vivo}. Our results show that the normal and the malignant tissues measured in the patient have clearly resolvable optical and physiological property differences that may be broadly useful in identifying and characterizing tumors.{copyright} 1997 Optical Society of America

  18. Effect of Kinesiology Tape on Measurements of Balance in Subjects With Chronic Ankle Instability: A Randomized Controlled Trial.

    Science.gov (United States)

    de-la-Torre-Domingo, Carlos; Alguacil-Diego, Isabel M; Molina-Rueda, Francisco; López-Román, Antonio; Fernández-Carnero, Josué

    2015-12-01

    To examine the immediate and prolonged effects (7d) of Kinesiology Tape (KT) on balance in subjects with chronic ankle instability using computerized dynamic posturography (CDP). A 7-day follow-up, single-blind randomized controlled trial. University community. Subjects (N=36) were screened for possible eligibility criteria, and 30 successfully completed the study protocol. Of these, 15 were randomly assigned to the experimental group (KT: 5 men, 10 women), and 15 were assigned to the control group (placebo tape: 10 men, 5 women). The experimental group was taped for a lateral ankle sprain with KT. In the control group, a placebo tape was used. Balance was assessed under the following 3 conditions: without taping, immediately after application, and after 7 days of use. The CDP device used in this study was the Smart Equitest version 8.2. CDP analysis was conducted using the Sensory Organization Test (SOT). As primaries outcome measures, the composite SOT score and composite SOT strategy were chosen. The partial score for SOT condition 2 and its strategy were considered as the secondary outcomes measures. Repeated-measures analysis of variance (ANOVA) demonstrated that there was not a significant interaction between group and time in the composite SOT score (F=.239; P=.73), SOT condition 2 (F=.333; P=.705), and SOT strategy 2 (F=.899; P=.43). Additionally, repeated-measures ANOVA showed a significant effect for time (composite SOT score: F=40.69; P≤.01; SOT condition 2: F=4.61; P=.014; SOT strategy 2: F=.899; P=.413; composite SOT strategy: F=15.14; P≤.01). Specifically, post hoc analysis showed that both groups obtained improvements in composite SOT scores immediately after tape application and 7 days of use. According to our results, the SOT scores of both the KT and control groups improved during follow-up. No differences between them were observed during the follow-up in most balance measurements. The observed changes may be related to a subjective increase

  19. Measurement of brain perfusion, blood volume, and blood-brain barrier permeability, using dynamic contrast-enhanced T(1)-weighted MRI at 3 tesla

    DEFF Research Database (Denmark)

    Larsson, Henrik B W; Courivaud, Frédéric; Rostrup, Egill

    2009-01-01

    Assessment of vascular properties is essential to diagnosis and follow-up and basic understanding of pathogenesis in brain tumors. In this study, a procedure is presented that allows concurrent estimation of cerebral perfusion, blood volume, and blood-brain permeability from dynamic T(1)-weighted...... imaging of a bolus of a paramagnetic contrast agent passing through the brain. The methods are applied in patients with brain tumors and in healthy subjects. Perfusion was estimated by model-free deconvolution using Tikhonov's method (gray matter/white matter/tumor: 72 +/- 16/30 +/- 8/56 +/- 45 mL/100 g...... on a pixel-by-pixel basis of cerebral perfusion, cerebral blood volume, and blood-brain barrier permeability....

  20. Prediction of periodontopathic bacteria in dental plaque of periodontal healthy subjects by measurement of volatile sulfur compounds in mouth air.

    Science.gov (United States)

    Kishi, Mitsuo; Ohara-Nemoto, Yuko; Takahashi, Masahiro; Kishi, Kayo; Kimura, Shigenobu; Aizawa, Fumie; Yonemitsu, Masami

    2013-03-01

    The aim of this study was to determine whether measurements of volatile sulfur compounds (VSCs) are useful to predict colonization of periodontopathic bacteria. For this purpose, we assessed the relationships among distributions of 4 species of periodontopathic bacteria in tongue coating and dental plaque, oral conditions including VSC concentration in mouth air, and smoking habit of periodontal healthy young subjects. The subjects were 108 young adults (mean age, 23.5±2.56 years) without clinical periodontal pockets. Information regarding smoking habit was obtained by interview. After VSC concentration in mouth, air was measured with a portable sulfide monitor (Halimeter(®)), non-stimulated saliva flow and dental caries status were assessed, and tongue coating and dental plaque samples were collected from the subjects. The tongue coating samples were weighed to determine the amount. The colonization of Porphyromonas gingivalis, Tannerella forsythia, Prevotella intermedia, and Treponema denticola in both tongue coating and plaque samples was investigated using species-specific polymerase chain reaction assays. Significant relationships were observed between the colonization of periodontopathic bacteria in tongue coating and plaque samples, especially that of P. gingivalis. VSC concentration showed the most significant association with colonization of P. gingivalis in both tongue coating and dental plaque. Logistic regression analysis demonstrated that the adjusted partial correlation coefficient [Exp(B)] values for VSC concentration with the colonization of P. gingivalis, P. intermedia, and T. denticola in dental plaque were 135, 35.4 and 10.4, respectively. In addition, smoking habit was also shown to be a significant variable in regression models [Exp(B)=6.19, 8.92 and 2.53, respectively]. Therefore, receiver operating characteristic analysis was performed to predict the colonization of periodontal bacteria in dental plaque in the subjects divided by smoking

  1. The Fluctuation of Intraocular Pressure Measured by a Contact Lens Sensor in Normal-Tension Glaucoma Patients and Nonglaucoma Subjects.

    Science.gov (United States)

    Tojo, Naoki; Abe, Shinya; Ishida, Masaaki; Yagou, Takaaki; Hayashi, Atsushi

    2017-03-01

    We compared the fluctuation of intraocular pressure (IOP) in normal-tension glaucoma (NTG) patients and individuals with nonglaucoma eyes. We obtained continuous IOP values using a SENSIMED Triggerfish contact lens sensor. The eyes of 12 nonglaucoma subjects and 14 NTG patients were examined. In all 26 subjects, the IOP fluctuation was measured continuously for 24 hours with a contact lens sensor. We evaluated the range of IOP fluctuations over the 24-hour period separately for diurnal IOP and nocturnal IOP and identified each subject's maximum value. The range of IOP fluctuation were analyzed, cutoff level of IOP fluctuation was calculated using receiver operating characteristic curve analyses. The mean IOP in the NTG eyes was 11.5±2.4 mm Hg and that in the nonglaucoma eyes was 12.7±2.0 mm Hg, a nonsignificantly difference (P=0.175). The 24-hour range of IOP fluctuations in the NTG group was significantly larger than that of the nonglaucoma group (P=0.007). The percentage of NTG patients who had the peak time of IOP fluctuation during nocturnal sleep was 57.1%, whereas the corresponding rate for the nonglaucoma eyes was 91.7%. The cutoff level of IOP fluctuation for glaucoma was 442 mVeq (sensitivity=1.00; specificity=0.571). The range of IOP fluctuation was larger in the eyes with NTG than in the nonglaucoma eyes. This larger fluctuation might be one of the reasons underlying the aggravation of the visual field by NTG. Measurements of 24-hour continuous IOP might be one of the useful methods to distinguish NTG from nonglaucoma eyes.

  2. Love as a subjective corrlate of interpersonal relationships: attempts of defining of the concepts and methods of measurment

    Directory of Open Access Journals (Sweden)

    O. P. Zolotnyik

    2015-04-01

    Full Text Available This article is devoted to overview the scientific study of the phenomenon of love. Attempts of scientific knowledge presented by developed by sociologists and psychologists love theories, which defined, classified and measure this phenomenon. The paper proposed to review the most popular theory of love studying: the triangular theory of love for Robert J. Sternberg, classification styles love for John Alan Lee and transformational concept of A.Giddens. The importance of studying this subject is explained by the subjective definition by respondents of the role of love as correlates of interpersonal relationships. Love is considered as a factor that acts as a marriage motive and components, which ensures its durability. The complexity of the scientific understanding of love is the absence of clear empirical referents for fixation. The examined theory reaffirms their scientific hypotheses through the use of specific methods of measurement. It is offered for review: Scale of love and sympathy by Z.Rubin, Love Attitude Scale by Hendrick C. and Hendrick S. and scale of romantic relationships by Munro­Adams. These methodologies are widely used in modern scientific research, been undergo with modifications and adaptation depending on the cultural characteristics of the respondents. The phenomenon of love needs more scientific study with the aim of further categorization, require range of techniques selection and should be included  as a component in the sociological survey of interpersonal relationships.

  3. Analysis of microvascular perfusion with multi-dimensional complete ensemble empirical mode decomposition with adaptive noise algorithm: Processing of laser speckle contrast images recorded in healthy subjects, at rest and during acetylcholine stimulation.

    Science.gov (United States)

    Humeau-Heurtier, Anne; Marche, Pauline; Dubois, Severine; Mahe, Guillaume

    2015-01-01

    Laser speckle contrast imaging (LSCI) is a full-field imaging modality to monitor microvascular blood flow. It is able to give images with high temporal and spatial resolutions. However, when the skin is studied, the interpretation of the bidimensional data may be difficult. This is why an averaging of the perfusion values in regions of interest is often performed and the result is followed in time, reducing the data to monodimensional time series. In order to avoid such a procedure (that leads to a loss of the spatial resolution), we propose to extract patterns from LSCI data and to compare these patterns for two physiological states in healthy subjects: at rest and at the peak of acetylcholine-induced perfusion peak. For this purpose, the recent multi-dimensional complete ensemble empirical mode decomposition with adaptive noise (MCEEMDAN) algorithm is applied to LSCI data. The results show that the intrinsic mode functions and residue given by MCEEMDAN show different patterns for the two physiological states. The images, as bidimensional data, can therefore be processed to reveal microvascular perfusion patterns, hidden in the images themselves. This work is therefore a feasibility study before analyzing data in patients with microvascular dysfunctions.

  4. Use of laser speckle contrast imaging to reveal changes in temperature and blood perfusion in the skin of healthy subjects after administration of heated moxa sticks and daiwenjiu ointment.

    Science.gov (United States)

    Xu, Qingyan; Yang, Jinsheng; Wang, Liang; Deng, Zi; Wang, Yingying; Yang, Li; Wu, Peng; Li, Liang

    2014-08-01

    To investigate the influence of heated moxa sticks ("moxibustion") and Daiwenjiu ointment (DO) on changes in temperature and blood perfusion volume on the skin of the backs of healthy subjects. DO was spread on the left side of the body, and the right side of the body was treated with a heated moxa stick. Images denoting blood perfusion and body temperature were collected 7-8 cm lateral to the spinous process of the sixth thoracic vertebra using laser speckle contrast imaging (LSCI). Data obtained from eight-frame images were analyzed and used to calculate the mean blood perfusion volume. Simultaneously, blood-perfusion images were collected from the body surface and used to compare the change in blood flow on the body surface and the actual position of imaging. After moxibustion, a rapid increase in blood perfusion volume and body temperature was noted in the local skin surface. The maximum blood perfusion volume and body temperature was noted at 20 min (P temperature (P temperature after treatment with moxibustion, but the respective changes seen in the DO group were gradual and moderate.

  5. Comparison of blood velocity measurements between ultrasound Doppler and accelerated phase-contrast MR angiography in small arteries with disturbed flow

    Energy Technology Data Exchange (ETDEWEB)

    Jiang Jingfeng; Johnson, Kevin; Wieben, Oliver; Zagzebski, James [Medical Physics Department, University of Wisconsin-Madison School of Medicine and Public Health, WI (United States); Strother, Charles; Consigny, Dan [Radiology Department, University of Wisconsin-Madison School of Medicine and Public Health, WI (United States); Baker, Sara, E-mail: jjiang2@wisc.edu [School of Ultrasound, University of Wisconsin-Madison School of Medicine and Public Health, WI (United States)

    2011-03-21

    Ultrasound Doppler (UD) velocity measurements are commonly used to quantify blood flow velocities in vivo. The aim of our work was to investigate the accuracy of in vivo spectral Doppler measurements of velocity waveforms. Waveforms were derived from spectral Doppler signals and corrected for intrinsic spectral broadening errors by applying a previously published algorithm. The method was tested in a canine aneurysm model by determining velocities in small arteries (3-4 mm diameter) near the aneurysm where there was moderately disturbed flow. Doppler results were compared to velocity measurements in the same arteries acquired with a rapid volumetric phase contrast MR angiography technique named phase contrast vastly undersampled isotropic projection reconstruction magnetic resonance angiography (PC-VIPR MRA). After correcting for intrinsic spectral broadening, there was a high degree of correlation between velocities obtained by the real-time UD and the accelerated PC-MRA technique. The peak systolic velocity yielded a linear correlation coefficient of r = 0.83, end diastolic velocity resulted in r = 0.81, and temporally averaged mean velocity resulted in r = 0.76. The overall velocity waveforms obtained by the two techniques were also highly correlated (r = 0.89 {+-} 0.06). There were, however, only weak correlations for the pulsatility index (PI: 0.25) and resistive index (RI: 0.14) derived from the two techniques. Results demonstrate that to avoid overestimations of peak systolic velocities, the results for UD must be carefully corrected to compensate for errors caused by intrinsic spectral broadening.

  6. Comparison of blood velocity measurements between ultrasound Doppler and accelerated phase-contrast MR angiography in small arteries with disturbed flow

    Science.gov (United States)

    Jiang, Jingfeng; Strother, Charles; Johnson, Kevin; Baker, Sara; Consigny, Dan; Wieben, Oliver; Zagzebski, James

    2011-03-01

    Ultrasound Doppler (UD) velocity measurements are commonly used to quantify blood flow velocities in vivo. The aim of our work was to investigate the accuracy of in vivo spectral Doppler measurements of velocity waveforms. Waveforms were derived from spectral Doppler signals and corrected for intrinsic spectral broadening errors by applying a previously published algorithm. The method was tested in a canine aneurysm model by determining velocities in small arteries (3-4 mm diameter) near the aneurysm where there was moderately disturbed flow. Doppler results were compared to velocity measurements in the same arteries acquired with a rapid volumetric phase contrast MR angiography technique named phase contrast vastly undersampled isotropic projection reconstruction magnetic resonance angiography (PC-VIPR MRA). After correcting for intrinsic spectral broadening, there was a high degree of correlation between velocities obtained by the real-time UD and the accelerated PC-MRA technique. The peak systolic velocity yielded a linear correlation coefficient of r = 0.83, end diastolic velocity resulted in r = 0.81, and temporally averaged mean velocity resulted in r = 0.76. The overall velocity waveforms obtained by the two techniques were also highly correlated (r = 0.89 ± 0.06). There were, however, only weak correlations for the pulsatility index (PI: 0.25) and resistive index (RI: 0.14) derived from the two techniques. Results demonstrate that to avoid overestimations of peak systolic velocities, the results for UD must be carefully corrected to compensate for errors caused by intrinsic spectral broadening.

  7. The effect of spatial resolution on wall shear stress measurements acquired using radial phase contrast magnetic resonance angiography in the middle cerebral arteries of healthy volunteers. Preliminary results.

    Science.gov (United States)

    Chang, W; Frydrychowicz, A; Kecskemeti, S; Landgraf, B; Johnson, K; Wu, Y; Wieben, O; Mistretta, C; Turski, P

    2011-03-29

    We have recently implemented radial phase-contrast techniques that allow high resolution angiograms with velocity information to be acquired within clinically-useful imaging times. 10 healthy volunteers were scanned using PC-VIPR and PC-SOS, two high resolution phase-contrast techniques at spatial resolutions of 0.67×0.67×0.67 mm(3) and 0.4×0.4×1 mm(3) respectively. The velocity measurements from the two acquisitions were imported into a custom Matlab runtime environment that automatically calculated WSS values using Green's Theorem and B-spline interpolation. Time average axial WSS was 1.069 N/m(2) (95% confidence interval: 0.8628volunteers (n=20) when scanned by PC-VIPR, and 1.670 N/m(2) when scanned by PC-SOS (95% confidence interval: 1.395 measurements because smaller voxel size results in fewer partial volume effects. This was true in our study as well. In this study, we found that PC-SOS has significantly higher spatial resolution than PC-VIPR and this followed in the WSS measurements. Higher in-plane spatial resolution allows WSS calculations to be performed more accurately because of increased precision near the vessel boundary.

  8. Measurement of the complex permittivity of microbubbles using a cavity perturbation technique for contrast enhanced ultra-wideband breast cancer detection.

    Science.gov (United States)

    Ogunlade, Olumide; Chen, Yifan; Kosmas, Panagiotis

    2010-01-01

    Measurements of the complex permittivity of various concentrations of microbubbles in ethylene glycol liquid phantom have been carried out. A cavity perturbation technique using custom rectangular waveguide cavities, which are sensitive to small changes in the permittivity of the perturber, has been employed. Three different frequencies within the ultra-wideband (UWB) frequency spectrum have been used for the experiments. The results show that the concentration of the air filled microbubbles required to achieve a dielectric contrast as little as 2% exceeds the recommended dosage used in clinical ultrasound applications, by more than two orders of magnitude.

  9. Effects of a Straw Phonation Protocol on Acoustic Measures of an SATB Chorus Singing Two Contrasting Renaissance Works.

    Science.gov (United States)

    Manternach, Jeremy N; Clark, Chad; Daugherty, James F

    2017-07-01

    Researchers have found that semi-occluded vocal tract (SOVT) exercises may increase vocal economy by reducing phonation threshold pressure and effort while increasing or maintaining consistent acoustic output. This research has focused solely on individual singers. Much singing instruction, however, takes place in choral settings. Choral singers may use different resonance strategies or unconsciously adjust their singing based on the ability to hear their own sound in relation to others. Results of studies with individual singers, then, may not be directly applicable to choral settings. The purpose of this investigation was to measure the effect of an SOVT protocol (ie, straw phonation) on acoustic changes of conglomerate, choral sound. This is a quasi-experimental, one-group, pretest-posttest design. Participants in this study constituted an intact SATB choir (soprano, alto, tenor, and bass) (N = 15 singers) who performed from memory two unaccompanied pieces of varied tempos from memory, participated in a 4-minute straw phonation protocol with a small stirring straw, and then sang each piece a second time. The long-term average spectrum results indicated small, statistically significant increases in spectral energy for both pieces in the 0-10 kHz (.32 and .20 dB Sound Pressure Level) and 2-4 kHz regions (.46 and .25 dB SPL). These results, although not likely audible to average hearing humans, seem consistent with the assertion that singers enjoy vocal benefits with consistent or increased vocal output. SOVT exercises, therefore, may be useful as a time-efficient way to evoke more efficient and economical singing during choral warm-up and voice building procedures. Copyright © 2017 The Voice Foundation. Published by Elsevier Inc. All rights reserved.

  10. Sex differences in objective measures of sleep in post-traumatic stress disorder and healthy control subjects.

    Science.gov (United States)

    Richards, Anne; Metzler, Thomas J; Ruoff, Leslie M; Inslicht, Sabra S; Rao, Madhu; Talbot, Lisa S; Neylan, Thomas C

    2013-12-01

    A growing literature shows prominent sex effects for risk for post-traumatic stress disorder and associated medical comorbid burden. Previous research indicates that post-traumatic stress disorder is associated with reduced slow wave sleep, which may have implications for overall health, and abnormalities in rapid eye movement sleep, which have been implicated in specific post-traumatic stress disorder symptoms, but most research has been conducted in male subjects. We therefore sought to compare objective measures of sleep in male and female post-traumatic stress disorder subjects with age- and sex-matched control subjects. We used a cross-sectional, 2 × 2 design (post-traumatic stress disorder/control × female/male) involving83 medically healthy, non-medicated adults aged 19-39 years in the inpatient sleep laboratory. Visual electroencephalographic analysis demonstrated that post-traumatic stress disorder was associated with lower slow wave sleep duration (F(3,82)  = 7.63, P = 0.007) and slow wave sleep percentage (F(3,82)  = 6.11, P = 0.016). There was also a group × sex interaction effect for rapid eye movement sleep duration (F(3,82)  = 4.08, P = 0.047) and rapid eye movement sleep percentage (F(3,82)  = 4.30, P = 0.041), explained by greater rapid eye movement sleep in post-traumatic stress disorder females compared to control females, a difference not seen in male subjects. Quantitative electroencephalography analysis demonstrated that post-traumatic stress disorder was associated with lower energy in the delta spectrum (F(3,82)  = 6.79, P = 0.011) in non-rapid eye movement sleep. Slow wave sleep and delta findings were more pronounced in males. Removal of post-traumatic stress disorder subjects with comorbid major depressive disorder, who had greater post-traumatic stress disorder severity, strengthened delta effects but reduced rapid eye movement effects to non-significance. These findings support previous evidence that post

  11. New measures of upper esophageal sphincter distensibility and opening patterns during swallowing in healthy subjects using EndoFLIP®

    LENUS (Irish Health Repository)

    Regan, J

    2013-01-01

    Background  This paper aims to measure upper esophageal sphincter (UES) distensibility and extent and duration of UES opening during swallowing in healthy subjects using EndoFLIP(®) . Methods  Fourteen healthy subjects (20-50 years) were recruited. An EndoFLIP(®) probe was passed trans-orally and the probe balloon was positioned across the UES. Two 20-mL ramp distensions were completed and UES cross-sectional area (CSA) and intra-balloon pressure (IBP) were evaluated. At 12-mL balloon volume, subjects completed dry, 5- and 10-mL liquid swallows and extent (mm) and duration (s) of UES opening and minimum IBP (mmHg) were analyzed across swallows. Key Results  Thirteen subjects completed the study protocol. A significant change in UES CSA (P < .001) and IBP (P < .000) was observed during 20-mL distension. UES CSA increased up to 10-mL distension (P < .001), from which point IBP raised significantly (P = 0.004). There were significant changes in UES diameter (mm) (P < .000) and minimum IBP (mmHg) (P < .000) during swallowing events. Resting UES diameter (4.9 mm; IQR 0.02) and minimum IBP (18.8 mmHg; IQR 2.64) changed significantly during dry (9.6 mm; IQR 1.3: P < .001) (3.6 mmHg; IQR 4.1: P = 0.002); 5 mL (8.61 mm; IQR 2.7: P < .001) (4.8 mmHg; IQR 5.7: P < .001) and 10-mL swallows (8.3 mm; IQR 1.6: P < 0.001) (3 mmHg; 4.6: P < .001). Median duration of UES opening was 0.5 s across dry and liquid swallows (P = 0.91). Color contour plots of EndoFLIP(®) data capture novel information regarding pharyngo-esophageal events during swallowing. Conclusions & Inferences  Authors obtained three different types of quantitative data (CSA, IBP, and timing) regarding UES distensibility and UES opening patterns during swallowing in healthy adults using only one device (EndoFLIP(®) ). This new measure of swallowing offers fresh information regarding UES dynamics which may ultimately improve patient

  12. Significantly Reduced Blood Pressure Measurement Variability for Both Normotensive and Hypertensive Subjects: Effect of Polynomial Curve Fitting of Oscillometric Pulses

    Directory of Open Access Journals (Sweden)

    Fangwei Yang

    2017-01-01

    Full Text Available This study aimed to compare within-subject blood pressure (BP variabilities from different measurement techniques. Cuff pressures from three repeated BP measurements were obtained from 30 normotensive and 30 hypertensive subjects. Automatic BPs were determined from the pulses with normalised peak amplitude larger than a threshold (0.5 for SBP, 0.7 for DBP, and 1.0 for MAP. They were also determined from cuff pressures associated with the above thresholds on a fitted curve polynomial curve of the oscillometric pulse peaks. Finally, the standard deviation (SD of three repeats and its coefficient of variability (CV were compared between the two automatic techniques. For the normotensive group, polynomial curve fitting significantly reduced SD of repeats from 3.6 to 2.5 mmHg for SBP and from 3.7 to 2.1 mmHg for MAP and reduced CV from 3.0% to 2.2% for SBP and from 4.3% to 2.4% for MAP (all P<0.01. For the hypertensive group, SD of repeats decreased from 6.5 to 5.5 mmHg for SBP and from 6.7 to 4.2 mmHg for MAP, and CV decreased from 4.2% to 3.6% for SBP and from 5.8% to 3.8% for MAP (all P<0.05. In conclusion, polynomial curve fitting of oscillometric pulses had the ability to reduce automatic BP measurement variability.

  13. Comparison of dual-energy X-ray absorptiometry and magnetic resonance imaging-measured adipose tissue depots in HIV-infected and control subjects.

    Science.gov (United States)

    Scherzer, Rebecca; Shen, Wei; Bacchetti, Peter; Kotler, Donald; Lewis, Cora E; Shlipak, Michael G; Punyanitya, Mark; Heymsfield, Steven B; Grunfeld, Carl

    2008-10-01

    Studies in persons without HIV infection have compared adipose tissue measured by dual-energy X-ray absorptiometry (DXA) and magnetic resonance imaging (MRI), but no such study has been conducted in HIV-infected (HIV+) subjects, who have a high prevalence of regional fat loss. We compared DXA- with MRI-measured trunk, leg, arm, and total fat in HIV+ and control subjects. A cross-sectional analysis was conducted in 877 HIV+ subjects and 260 control subjects in FRAM (Study of Fat Redistribution and Metabolic Change in HIV Infection), stratified by sex and HIV status. Univariate associations of DXA with MRI were strongest for total and trunk fat (r > or = 0.92) and slightly weaker for leg (r > or = 0.87) and arm (r > or = 0.71) fat. The average estimated limb fat was substantially greater for DXA than for MRI for HIV+ and control men and women (all P < 0.0001). Less of a difference was observed in trunk fat measured by DXA and MRI, but the difference was still statistically significant (P < 0.0001). Bland-Altman plots showed increasing differences and variability. Greater average limb fat in control and HIV+ subjects (both P < 0.0001) was associated with greater differences between DXA and MRI measurements. Because the control subjects had more limb fat than did the HIV+ subjects, greater amounts of fat were measured by DXA than by MRI when control subjects were compared with HIV+ subjects. More HIV+ subjects had leg fat in the bottom decile of the control subjects by DXA than by MRI (P < 0.0001). Although DXA- and MRI-measured adipose tissue depots correlate strongly in HIV+ and control subjects, differences increase as average fat increases, particularly for limb fat. DXA may estimate a higher prevalence of peripheral lipoatrophy than does MRI in HIV+ subjects.

  14. Diabetic Foot Prevention: Repeatability of the Loran Platform Plantar Pressure and Load Distribution Measurements in Nondiabetic Subjects during Bipedal Standing—A Pilot Study

    Directory of Open Access Journals (Sweden)

    Martha Zequera

    2011-01-01

    Full Text Available This study was designed to assess the repeatability of the Loran Platform and evaluate the variability of plantar pressure and postural balance, during barefoot standing in nondiabetic subjects, for future diabetic foot clinical evaluation. Measurements were taken for eight nondiabetic subjects (4 females, 4 males, aged 47±7.2 years who had no musculoskeletal symptoms. Five variables were measured with the platform in the barefoot standing position. Ten measurements were taken using two different techniques for feet and posture positioning, during three sessions, once a week. For most measurements, no significant effect over time was found with Student's t-test (P<.000125. The ANOVA test of statistical significance confirmed that measurement differences between subjects showed higher variations than measurements taken from the same subject (P<.001. The measurements taken by the Loran Platform system were found to be repeatable.

  15. Prevalence of Hand-transmitted Vibration Exposure among Grass-cutting Workers using Objective and Subjective Measures

    Science.gov (United States)

    Azmir, N. A.; Yahya, M. N.

    2017-01-01

    Extended exposure to hand-transmitted vibration from vibrating machine is associated with an increased occurrence of symptoms of occupational disease related to hand disorder. The present case study is to determine the prevalence and correlation of significant subjective as well as objective variables that induce to hand arm vibration syndrome (HAVS) among hand-held grass-cutting workers in Malaysia. Thus, recommendations are made for grass-cutting workers and grass maintenance service management based on findings. A cross sectional study using adopted subjective Hand Arm Vibration Exposure Risk Assessment (HAVERA) questionnaire from Vibration Injury Network on hand disorder signs and symptoms was distributed to a sample of one hundred and sixty eight male workers from grass and turf maintenance industry that use vibrating machine as part of their work. For objective measure, hand-transmitted vibration measurement was collected on site during operation by the following ISO 5349-1, 2001. Two groups were identified in this research comprising of high exposure group and low-moderate exposure group. Workers also gave information about their personal identification, social history, workers’ health, occupational history and machine safety inspection. There was positive HAVS symptoms relationship between the low-moderate exposure group and high exposure group among hand-held grass-cutting workers. The prevalence ratio (PR) was considered high for experiencing white colour change at fingers and fingers go numb which are 3.63 (1.41 to 9.39) and 4.24 (2.18 to 8.27), respectively. The estimated daily vibration exposure, A(8) differs between 2.1 to 20.7 ms-2 for right hand while 2.7 to 29.1 ms-2 for left hand. The subjects claimed that the feel of numbness at left hand is much stronger compared to right hand. The results suggest that HAVS is diagnosed in Malaysia especially in agriculture sector. The A(8) indicates that the exposure value is more than exposure limit value

  16. PP084. Magnetic resonance imaging measurements of T2 relaxation times within contrasting regions of murine placenta is dependent upon blood flow.

    Science.gov (United States)

    Bobek, G; Stait-Gardner, T; Surmon, L; Makris, A; Price, W S; Hennessy, A

    2012-07-01

    It has been postulated that reduced placental perfusion as a result of abnormal placental implantation is the initiating event that leads to the maternal symptoms of preeclampsia. To be able to directly measure blood flow and perfusion in the placenta in experimental models of preeclampsia would provide valuable insight into the structural abnormalities of this syndrome. Magnetic resonance imaging (MRI) offers visualization of anatomy and analysis of changes in tissue morphology and function including blood flow and perfusion. The major source of image contrast in MRI comes from the variation in relaxation times between tissues. Previously, human placenta has appeared as fairly homogeneous in studies of T1 and T2 relaxation times, with no internal morphology apparent. The aim of this study was to investigate, using much higher field strengths (11.7Tesla) and much higher resolution than have been used previously, whether structural inhomogeneities in the placenta can be discerned by T2 mapping and whether T2 mapping is capable of detecting structural abnormalities that may affect blood flow in a preeclamptic placenta. Magnetic resonance images were acquired on an anaesthetised C57BL/6JArc mouse placed in a vertical animal probe using a Bruker Avance 11.7Tesla wide-bore spectrometer with micro-imaging probe capable of generating gradients of 0.45T/m. T2 measurements were acquired using an MSME sequence protocol (Bruker MSME-T2-map) with an in-plane resolution of 0.1-0.2mm. Matlab was used to generate R2 (i.e., 1/T2) maps from the acquired data with the T2 values being calculated from selected regions of interest within 5 individual placenta. Additional T2 measurements were acquired on the same slices immediately after blood flow was reduced to zero. Three distinct regions of T2 contrast were discerned in the mouse placenta, likely correlating to the labrynthine, junctional and decidual zones. The contrast between the inner two regions was substantially abrogated when

  17. Non-invasive evaluation of energy loss in the pulmonary arteries using 4D phase contrast MR measurement: a proof of concept.

    Science.gov (United States)

    Lee, Namheon; Taylor, Michael D; Hor, Kan N; Banerjee, Rupak K

    2013-09-23

    The repair surgery of congenital heart disease (CHD) associated with the right ventricular (RV)-pulmonary artery (PA) pathophysiology often left patients with critical post-operative lesions, leading to regurgitation and obstruction in the PAs. These lesions need longitudinal (with time) assessment for monitoring the RV function, in order for patients to have appropriate treatment before irreversible RV dysfunction occurs. In this research, we computed energy loss in the branch PAs using blood flow and pressure drop data obtained from 4D phase contrast (PC) MRI, to non-invasively quantify the RV-PA pathophysiology. 4D PC MRI was acquired for a CHD patient with abnormal RV-PA physiology, including pulmonary regurgitation and PA stenosis, and a subject with normal RV-PA physiology. The blood velocity, flow rate, and pressure drop data, obtained from 4D PC MRI, were used to compute and compare the energy loss values between the patient and normal subjects. The pressure drop in the branch PAs for the patient was -1.3 mmHg/s and -0.2 mmHg/s for the RPA and LPA, respectively, and was larger (one order of magnitude) than that for the control. Similarly, the total energy loss in the branch PAs for the patient, -96.9 mJ/s and -16.4 mJ/s, for the RPA and LPA, respectively, was larger than that for the control. The amount of energy loss in the pulmonary blood flow for the patient was considerably larger than the normal subject due to PA regurgitation and PA stenosis. Thus, we believe that the status of RV-PA pathophysiology for CHD patients can be evaluated non-invasively using energy loss endpoint.

  18. A toolkit for clinical statisticians to fix problems based on biomarker measurements subject to instrumental limitations: from repeated measurement techniques to a hybrid pooled-unpooled design.

    Science.gov (United States)

    Vexler, Albert; Tao, Ge; Chen, Xiwei

    2015-01-01

    The aim of this chapter is to review and examine different methods in order to display correct and efficient statistical techniques based on complete/incomplete data subject to different sorts of measurement error (ME) problems. Instrument inaccuracies, biological variations, and/or errors in questionnaire-based self-report data can lead to significant MEs in various clinical experiments. Ignoring MEs can cause bias or inconsistency of statistical inferences. The biostatistical literature well addresses two categories of MEs: errors related to additive models and errors caused by the limit of detection (LOD). Several statistical approaches have been developed to analyze data affected by MEs, including the parametric/nonparametric likelihood methodologies, Bayesian methods, the single and multiple imputation techniques, and the repeated measurement design of experiment. We present a novel hybrid pooled-unpooled design as one of the strategies to provide correct statistical inferences when data is subject to MEs. This hybrid design and the classical techniques are compared to show the advantages and disadvantages of the considered methods.

  19. Correlation of pretreatment polarographically measured oxygen pressures with quantified contrast-enhanced power doppler ultrasonography in spontaneous canine tumors and their impact on outcome after radiation therapy

    Energy Technology Data Exchange (ETDEWEB)

    Rohrer Bley, Carla; Laluhova, Dagmar [Section of Radiooncology, Vetsuisse Faculty, Univ. of Zurich (Switzerland); Roos, Malgorzata [Inst. for Social and Preventive Medicine, Medical Faculty, Univ. of Zurich (Switzerland); Kaser-Hotz, Barbara [Section of Radiooncology, Vetsuisse Faculty, Univ. of Zurich (Switzerland); Section Imaging Diagnostics, Vetsuisse Faculty, Univ. of Zurich (Switzerland); Ohlerth, Stefanie [Section Imaging Diagnostics, Vetsuisse Faculty, Univ. of Zurich (Switzerland)

    2009-11-15

    Purpose: to evaluate the use of noninvasive quantified contrast-enhanced power Doppler ultrasonography as a surrogate in the estimation of tumor hypoxia measured by invasive pO{sub 2} histography in canine tumors. Material and methods: data of pretreatment tumor oxygenation status, tumor vascularity and blood volume, and tumor response after radiation therapy was collected in 48 spontaneous malignant oral tumors (Table 1). Tumor oxygenation status was correlated to vascularity and blood volume, and influences on outcome after treatment were analyzed. Results: although vascularity and blood volume correlated moderately with median pO{sub 2} (r = 0.51 and 0.61; p = 0.001 and < 0.0001) and percentage of pO{sub 2} readings {<=} 2.5, 5, and 10 mmHg (r = -0.37 to -0.42; p < 0.01-0.03) for all tumors, they did not correlate within the different histology groups (p = 0.06-0.9). For all tumors, pretreatment oxygenation status, vascularity and blood volume were not found to be of prognostic value. Conclusion: these analyses show that quantified contrast-enhanced power Doppler ultrasonography does not represent a non-invasive indirect method to assess tumor hypoxia measured by invasive pO{sub 2} histography. Both technologies were nonprognostic indicators in spontaneous malignant canine oral tumors. (orig.)

  20. Wrist flexion and extension torques measured by highly sensitive dynamometer in healthy subjects from 5 to 80 years.

    Science.gov (United States)

    Decostre, Valérie; Canal, Aurélie; Ollivier, Gwenn; Ledoux, Isabelle; Moraux, Amélie; Doppler, Valérie; Payan, Christine Anne Mary; Hogrel, Jean-Yves

    2015-01-31

    Wrist movements become impaired with disease progression in various neuromuscular disorders. With the development of new therapies, thorough measurement of muscle strength is crucial to document natural disease progression and to assess treatment efficacy. We developed a new dynamometer enabling wrist flexion and extension torque measurement with high sensitivity. The aims of the present study were to collect norms for healthy children and adults, to compute predictive equations, to assess the reliability of the measurements and to test the feasibility of using the device in patients with a neuromuscular disease. The peak isometric torque of wrist flexion and extension was measured with the MyoWrist dynamometer in 345 healthy subjects aged between 5 and 80 years old and in 9 patients with limb girdle muscle dystrophy type 2 C (LGMD2C) aged between 16 and 38 years old. Predictive equations are proposed for the wrist flexion and extension strength in children and adults. Intra-rater and inter-rater reliability was good with ICCs higher than 0.9 for both wrist flexion and extension. However, retest values were significantly higher by 4% than test results. The dynamometer was applied with no difficulty to patients with LGMD2C and was sensitive enough to detect strength as weak as 0.82 N.m. From our models, we quantified the mean strength of wrist extension in LGMD2C patients to 39 ± 17% of their predicted values. The MyoWrist dynamometer provides reliable and sensitive measurement of both wrist flexion and extension torques. However, a training session is recommended before starting a study as a small but significant learning effect was observed. Strength deficit can be quantified from predictive equations that were computed from norms of healthy children and adults.

  1. The value of the acoustic voice quality index as a measure of dysphonia severity in subjects speaking different languages.

    Science.gov (United States)

    Maryn, Youri; De Bodt, Marc; Barsties, Ben; Roy, Nelson

    2014-06-01

    The Acoustic Voice Quality Index (AVQI) is a relatively new clinical method to quantify dysphonia severity. Since it partially relies on continuous speech, its performance may vary with voice-related phonetic differences and thus across languages. The present investigation therefore assessed the AVQI's performance in English, Dutch, German, and French. Fifty subjects were recorded reading sentences in the four languages, as well as producing a sustained vowel. These recordings were later edited to calculate the AVQI. The samples were also perceptually rated on overall dysphonia severity by three experienced voice clinicians. The AVQI's cross-linguistic concurrent validity and diagnostic precision were assessed. The results support earlier data, and confirm good cross-linguistic validity and diagnostic accuracy. Although no statistical differences were observed between languages, the AVQI performed better in English and German and less well in French. These results validate the AVQI as a potentially robust and objective dysphonia severity measure across languages.

  2. The influence of N-acetylcysteine on the measurement of prothrombin time and activated partial thromboplastin time in healthy subjects

    DEFF Research Database (Denmark)

    Jepsen, S; Hansen, A B

    1994-01-01

    The purpose of the study was to evaluate whether the infusion of N-acetylcysteine decreased the measurement of prothrombin time and activated partial thromboplastin time (APTT) in healthy persons. N-acetylcysteine was administered intraveneously 10 mg kg-1 as a loading dose and then at a rate of 10...... mg kg-1 h-1 for 32 h in six male subjects. The intrinsic, extrinsic and common pathway of coagulation were monitored with activated partial thromboplastin time (APTT), and prothrombin time, respectively. In addition, the extrinsic coagulation pathway was monitored with the clotting activity of single...... factors II, VII, and X. No effect on the intrinsic coagulation pathway was observed. There was a significant and rapid decrease in prothrombin time. Coagulation factors II, VII and X, the three components of prothrombin time, decreased significantly to different degrees. We conclude that infusion of N...

  3. Relationship between knee kinetic outcome measures in vertical counter movement jumps and self-reported function in ACL reconstructed subjects

    DEFF Research Database (Denmark)

    Brekke, Anders Falk

    2014-01-01

    and Traumatology, Odense University Hospital, Institute of Clinical Research, University of Southern Denmark Introduction: Altered loading pattern of the medial aspect of the knee has been associated with the development of knee osteoarthritis (OA). Anterior cruciate ligament (ACL) injuries are associated......Relationship between knee kinetic outcome measures in counter movement jumps and self-reported function in ACL reconstructed subjects Brekke AF1,2, Nielsen DB2, Holsgaard-Larsen A2 1School of physiotherapy, University College Zealand, Denmark 2Orthopaedic Research Unit, Department of Orthopaedics...... with early-onset OA with associated pain, functional limitations, and decreased quality of life. However, specific knee loading pattern of the medial aspect has not been investigated during different jump-tasks in ACL-reconstructed patients. The purpose was to investigate potential kinetic differences...

  4. Bone mineral density measurements of the proximal femur from routine contrast-enhanced MDCT data sets correlate with dual-energy X-ray absorptiometry.

    Science.gov (United States)

    Gruber, M; Bauer, J S; Dobritz, M; Beer, A J; Wolf, P; Woertler, K; Rummeny, E J; Baum, T

    2013-02-01

    To evaluate the utility of femoral bone mineral density (BMD) measurements in routine contrast-enhanced multi-detector computed tomography (ceMDCT) using dual-energy X-ray absorptiometry (DXA) as the reference standard. Forty-one patients (33 women, 8 men) underwent DXA measurement of the proximal femur. Subsequently, transverse sections of routine ceMDCT of these patients were used to measure BMD of the femoral head and femoral neck. The MDCT-to-DXA conversion equations for BMD and T-score were calculated using linear regression analysis. The conversion equations were applied to the MDCT data sets of 382 patients (120 women, 262 men) of whom 74 had osteoporotic fractures. A correlation coefficient of r = 0.84 (P < 0.05) was calculated for BMD(MDCT) values of the femoral head and DXA T-scores of the total proximal femur using the conversion equation T-score = 0.021 × BMD(MDCT) - 5.90. The correlation coefficient for the femoral neck was r = 0.79 (P < 0.05) with the conversion equation T-score = 0.016 × BMD(MDCT) - 4.28. Accordingly, converted T-scores for the femoral neck in patients with versus those without osteoporotic fractures were significantly different (female, -1.83 versus -1.47; male, -1.86 versus -1.47; P < 0.05). BMD measurements of the proximal femur were computed in routine contrast-enhanced MDCT and converted to DXA T-scores, which adequately differentiated patients with and without osteoporotic fractures.

  5. Bone mineral density measurements of the proximal femur from routine contrast-enhanced MDCT data sets correlate with dual-energy X-ray absorptiometry

    Energy Technology Data Exchange (ETDEWEB)

    Gruber, M. [Medical University of Vienna, Department of Radiology, Division of Neuroradiology and Musculoskeletal Radiology, Vienna (Austria); Bauer, J.S.; Dobritz, M.; Woertler, K.; Rummeny, E.J.; Baum, T. [Technische Universitaet Muenchen, Department of Radiology, Klinikum rechts der Isar, Munich (Germany); Beer, A.J. [Technische Universitaet Muenchen, Department of Nuclear Medicine, Munich (Germany); Wolf, P. [Technische Universitaet Muenchen, Institute for Medical Statistics and Epidemiology, Munich (Germany)

    2013-02-15

    To evaluate the utility of femoral bone mineral density (BMD) measurements in routine contrast-enhanced multi-detector computed tomography (ceMDCT) using dual-energy X-ray absorptiometry (DXA) as the reference standard. Forty-one patients (33 women, 8 men) underwent DXA measurement of the proximal femur. Subsequently, transverse sections of routine ceMDCT of these patients were used to measure BMD of the femoral head and femoral neck. The MDCT-to-DXA conversion equations for BMD and T-score were calculated using linear regression analysis. The conversion equations were applied to the MDCT data sets of 382 patients (120 women, 262 men) of whom 74 had osteoporotic fractures. A correlation coefficient of r = 0.84 (P < 0.05) was calculated for BMD{sub MDCT} values of the femoral head and DXA T-scores of the total proximal femur using the conversion equation T-score = 0.021 x BMD{sub MDCT} - 5.90. The correlation coefficient for the femoral neck was r = 0.79 (P < 0.05) with the conversion equation T-score = 0.016 x BMD{sub MDCT} - 4.28. Accordingly, converted T-scores for the femoral neck in patients with versus those without osteoporotic fractures were significantly different (female, -1.83 versus -1.47; male, -1.86 versus -1.47; P < 0.05). BMD measurements of the proximal femur were computed in routine contrast-enhanced MDCT and converted to DXA T-scores, which adequately differentiated patients with and without osteoporotic fractures. (orig.)

  6. The effect of valgus braces on medial compartment load of the knee joint - in vivo load measurements in three subjects.

    Science.gov (United States)

    Kutzner, Ines; Küther, Steffen; Heinlein, Bernd; Dymke, Jörn; Bender, Alwina; Halder, Andreas M; Bergmann, Georg

    2011-04-29

    Knee osteoarthritis occurs predominately at the medial compartment. To unload the affected compartment, valgus braces are used which induce an additional valgus moment in order to shift the load more laterally. Until now the biomechanical effect of braces was mainly evaluated by measuring changes in external knee adduction moments. The aim of this study was to investigate if and to which extent the medial compartment load is reduced in vivo when wearing valgus braces. Six components of joint contact load were measured in vivo in three subjects, using instrumented, telemeterized knee implants. From the forces and moments the medio-lateral force distribution was calculated. Two braces, MOS Genu (Bauerfeind AG) and Genu Arthro (Otto Bock) were investigated in neutral, 4° and 8° valgus adjustment during walking, stair ascending and descending. During walking with the MOS brace in 4°/8° valgus adjustment, medial forces were reduced by 24%/30% on average at terminal stance. During walking with the GA in the 8° valgus position, medial forces were reduced by only 7%. During stair ascending/descending significant reductions of 26%/24% were only observed with the MOS (8°). The load reducing ability of the two investigated valgus braces was confirmed in three subjects. However, the load reduction depends on the brace stiffness and its valgus adjustment and varies strongly inter-individually. Valgus adjustments of 8° might, especially with the MOS brace, not be tolerated by patients for a long time. Medial load reductions of more than 25% can therefore probably not be expected in clinical practise. Copyright © 2011 Elsevier Ltd. All rights reserved.

  7. Quantitative analysis of fluorescence lifetime measurements of the macula using the fluorescence lifetime imaging ophthalmoscope in healthy subjects.

    Science.gov (United States)

    Dysli, Chantal; Quellec, Gwénolé; Abegg, Mathias; Menke, Marcel N; Wolf-Schnurrbusch, Ute; Kowal, Jens; Blatz, Johannes; La Schiazza, Olivier; Leichtle, Alexander B; Wolf, Sebastian; Zinkernagel, Martin S

    2014-04-03

    Fundus autofluorescence (FAF) cannot only be characterized by the intensity or the emission spectrum, but also by its lifetime. As the lifetime of a fluorescent molecule is sensitive to its local microenvironment, this technique may provide more information than fundus autofluorescence imaging. We report here the characteristics and repeatability of FAF lifetime measurements of the human macula using a new fluorescence lifetime imaging ophthalmoscope (FLIO). A total of 31 healthy phakic subjects were included in this study with an age range from 22 to 61 years. For image acquisition, a fluorescence lifetime ophthalmoscope based on a Heidelberg Engineering Spectralis system was used. Fluorescence lifetime maps of the retina were recorded in a short- (498-560 nm) and a long- (560-720 nm) spectral channel. For quantification of fluorescence lifetimes a standard ETDRS grid was used. Mean fluorescence lifetimes were shortest in the fovea, with 208 picoseconds for the short-spectral channel and 239 picoseconds for the long-spectral channel, respectively. Fluorescence lifetimes increased from the central area to the outer ring of the ETDRS grid. The test-retest reliability of FLIO was very high for all ETDRS areas (Spearman's ρ = 0.80 for the short- and 0.97 for the long-spectral channel, P macula in healthy subjects. By using a custom-built software, we were able to quantify fluorescence lifetimes within the ETDRS grid. Establishing a clinically accessible standard against which to measure FAF lifetimes within the retina is a prerequisite for future studies in retinal disease.

  8. Reproducibility of heart rate variability parameters measured in healthy subjects at rest and after a postural change maneuver

    Directory of Open Access Journals (Sweden)

    E.M. Dantas

    2010-10-01

    Full Text Available Heart rate variability (HRV provides important information about cardiac autonomic modulation. Since it is a noninvasive and inexpensive method, HRV has been used to evaluate several parameters of cardiovascular health. However, the internal reproducibility of this method has been challenged in some studies. Our aim was to determine the intra-individual reproducibility of HRV parameters in short-term recordings obtained in supine and orthostatic positions. Electrocardiographic (ECG recordings were obtained from 30 healthy subjects (20-49 years, 14 men using a digital apparatus (sampling ratio = 250 Hz. ECG was recorded for 10 min in the supine position and for 10 min in the orthostatic position. The procedure was repeated 2-3 h later. Time and frequency domain analyses were performed. Frequency domain included low (LF, 0.04-0.15 Hz and high frequency (HF, 0.15-0.4 Hz bands. Power spectral analysis was performed by the autoregressive method and model order was set at 16. Intra-subject agreement was assessed by linear regression analysis, test of difference in variances and limits of agreement. Most HRV measures (pNN50, RMSSD, LF, HF, and LF/HF ratio were reproducible independent of body position. Better correlation indexes (r > 0.6 were obtained in the orthostatic position. Bland-Altman plots revealed that most values were inside the agreement limits, indicating concordance between measures. Only SDNN and NNv in the supine position were not reproducible. Our results showed reproducibility of HRV parameters when recorded in the same individual with a short time between two exams. The increased sympathetic activity occurring in the orthostatic position probably facilitates reproducibility of the HRV indexes.

  9. Portal hypertension in patients with cirrhosis: indirect assessment of hepatic venous pressure gradient by measuring azygos flow with 2D-cine phase-contrast magnetic resonance imaging.

    Science.gov (United States)

    Gouya, Hervé; Grabar, Sophie; Vignaux, Olivier; Saade, Anastasia; Pol, Stanislas; Legmann, Paul; Sogni, Philippe

    2016-07-01

    To measure azygos, portal and aortic flow by two-dimensional cine phase-contrast magnetic resonance imaging (2D-cine PC MRI), and to compare the MRI values to hepatic venous pressure gradient (HVPG) measurements, in patients with cirrhosis. Sixty-nine patients with cirrhosis were prospectively included. All patients underwent HVPG measurements, upper gastrointestinal endoscopy and 2D-cine PC MRI measurements of azygos, portal and aortic blood flow. Univariate and multivariate regression analyses were used to evaluate the correlation between the blood flow and HVPG. The performance of 2D-cine PC MRI to diagnose severe portal hypertension (HVPG ≥ 16 mmHg) was determined by receiver operating characteristic curve (ROC) analysis, and area under the curves (AUC) were compared. Azygos and aortic flow values were associated with HVPG in univariate linear regression model. Azygos flow (p cine PC MRI is a promising technique to evaluate significant portal hypertension in patients with cirrhosis. • Noninvasive HVPG assessment can be performed with MRI azygos flow. • Azygos MRI flow is an easy-to-measure marker to detect significant portal hypertension. • MRI flow is more specific that varice grade to detect portal hypertension.

  10. Supraclavicular skin temperature as a measure of 18F-FDG uptake by BAT in human subjects.

    Directory of Open Access Journals (Sweden)

    Mariëtte R Boon

    Full Text Available Brown adipose tissue (BAT has emerged as a novel player in energy homeostasis in humans and is considered a potential new target for combating obesity and related diseases. The current 'gold standard' for quantification of BAT volume and activity is cold-induced 18F-FDG uptake in BAT. However, use of this technique is limited by cost and radiation exposure. Given the fact that BAT is a thermogenic tissue, mainly located in the supraclavicular region, the aim of the current study was to investigate whether cold-induced supraclavicular skin temperature and core body temperature may be alternative markers of BAT activation in humans.BAT volume and activity were measured in 24 healthy lean adolescent males (mean age 24.1±0.8 years, using cold-induced 18F-FDG uptake with PET-CT. Core body temperature was measured continuously in the small intestine with use of an ingestible telemetric capsule and skin temperature was measured by eighteen wireless iButtons attached to the skin following ISO-defined locations.Proximal and distal (hand/feet skin temperatures markedly decreased upon cold exposure, while supraclavicular skin temperature significantly increased (35.2±0.1 vs. 35.5±0.1°C, p = 0.001. Furthermore, cold-induced supraclavicular skin temperature positively correlated with both total (R2 = 0.28, P = 0.010 and clavicular BAT volume (R2 = 0.20, P = 0.030 and clavicular SUVmax (R2 = 0.27, P = 0.010, while core body temperature did not.Supraclavicular skin temperature as measured by iButtons may have predictive value for BAT detection in adult humans. This is highly desirable considering the increasing interest in pharmacological interventions to stimulate BAT in human subjects.NTR 2473.

  11. Effect of postprandial hyperglycaemia in non-invasive measurement of cerebral metabolic rate of glucose in non-diabetic subjects

    Energy Technology Data Exchange (ETDEWEB)

    Tsuchida, Tatsuro; Itoh, Harumi [Department of Radiology, Fukui Medical University, Matsuoka (Japan); Sadato, Norihiro; Nishizawa, Sadahiko; Yonekura, Yoshiharu [Biomedical Imaging Research Center, Fukui Medical University (Japan)

    2002-02-01

    The aim of this study was to determine the effect of postprandial hyperglycaemia (HG) on the non-invasive measurement of cerebral metabolic rate of glucose (CMRGlc). Five patients who had a meal within an hour before a fluorine-18 fluorodeoxyglucose positron emission tomography (FDG-PET) examination were recruited in this study. They underwent intermittent arterial blood sampling (measured input function), and, based on this sampling, CMRGlc was calculated using an autoradiographic method (CMRGlc{sub real}). Simulated input functions were generated based on standardised input function, body surface area and net injected dose of FDG, and simulated CMRGlc (CMRGlc{sub sim}) was also calculated. Percent error of the area under the curve (AUC) between measured (AUC{sub real}) and simulated input function (AUC{sub IFsim}) and percent error between CMRGlc{sub real} and CMRGlc{sub sim} were calculated. These values were compared with those obtained from a previous study conducted under fasting conditions (F). The serum glucose level in the HG group was significantly higher than that in the F group (165{+-}69 vs 100{+-}9 mg/dl, P=0.0007). Percent errors of AUC and CMRGlc in grey matter and white matter in HG were significantly higher than those in F (12.9%{+-}1.3% vs 3.5%{+-}2.2% in AUC, P=0.0015; 18.2%{+-}2.2% vs 2.9%{+-}1.9% in CMRGlc in grey matter, P=0.0028; 24.0%{+-}4.6% vs 3.4%{+-}2.2% in CMRGlc in white matter, P=0.0028). It is concluded that a non-invasive method of measuring CMRGlc should be applied only in non-diabetic subjects under fasting conditions. (orig.)

  12. Comprehensively Measuring Health-Related Subjective Well-Being: Dimensionality Analysis for Improved Outcome Assessment in Health Economics.

    Science.gov (United States)

    de Vries, Marieke; Emons, Wilco H M; Plantinga, Arnoud; Pietersma, Suzanne; van den Hout, Wilbert B; Stiggelbout, Anne M; van den Akker-van Marle, M Elske

    2016-01-01

    Allocation of inevitably limited financial resources for health care requires assessment of an intervention's effectiveness. Interventions likely affect quality of life (QOL) more broadly than is measurable with commonly used health-related QOL utility scales. In line with the World Health Organization's definition of health, a recent Delphi procedure showed that assessment needs to put more emphasis on mental and social dimensions. To identify the core dimensions of health-related subjective well-being (HR-SWB) for a new, more comprehensive outcome measure. We formulated items for each domain of an initial Delphi-based set of 21 domains of HR-SWB. We tested these items in a large sample (N = 1143) and used dimensionality analyses to find a smaller number of latent factors. Exploratory factor analysis suggested a five-factor model, which explained 65% of the total variance. Factors related to physical independence, positive affect, negative affect, autonomy, and personal growth. Correlations between the factors ranged from 0.19 to 0.59. A closer inspection of the factors revealed an overlap between the newly identified core dimensions of HR-SWB and the validation scales, but the dimensions of HR-SWB also seemed to reflect additional aspects. This shows that the dimensions of HR-SWB we identified go beyond the existing health-related QOL instruments. We identified a set of five key dimensions to be included in a new, comprehensive measure of HR-SWB that reliably captures these dimensions and fills in the gaps of the existent measures used in economic evaluations. Copyright © 2016 International Society for Pharmacoeconomics and Outcomes Research (ISPOR). Published by Elsevier Inc. All rights reserved.

  13. Supraclavicular skin temperature as a measure of 18F-FDG uptake by BAT in human subjects.

    Science.gov (United States)

    Boon, Mariëtte R; Bakker, Leontine E H; van der Linden, Rianne A D; Pereira Arias-Bouda, Lenka; Smit, Frits; Verberne, Hein J; van Marken Lichtenbelt, Wouter D; Jazet, Ingrid M; Rensen, Patrick C N

    2014-01-01

    Brown adipose tissue (BAT) has emerged as a novel player in energy homeostasis in humans and is considered a potential new target for combating obesity and related diseases. The current 'gold standard' for quantification of BAT volume and activity is cold-induced 18F-FDG uptake in BAT. However, use of this technique is limited by cost and radiation exposure. Given the fact that BAT is a thermogenic tissue, mainly located in the supraclavicular region, the aim of the current study was to investigate whether cold-induced supraclavicular skin temperature and core body temperature may be alternative markers of BAT activation in humans. BAT volume and activity were measured in 24 healthy lean adolescent males (mean age 24.1±0.8 years), using cold-induced 18F-FDG uptake with PET-CT. Core body temperature was measured continuously in the small intestine with use of an ingestible telemetric capsule and skin temperature was measured by eighteen wireless iButtons attached to the skin following ISO-defined locations. Proximal and distal (hand/feet) skin temperatures markedly decreased upon cold exposure, while supraclavicular skin temperature significantly increased (35.2±0.1 vs. 35.5±0.1°C, p = 0.001). Furthermore, cold-induced supraclavicular skin temperature positively correlated with both total (R2 = 0.28, P = 0.010) and clavicular BAT volume (R2 = 0.20, P = 0.030) and clavicular SUVmax (R2 = 0.27, P = 0.010), while core body temperature did not. Supraclavicular skin temperature as measured by iButtons may have predictive value for BAT detection in adult humans. This is highly desirable considering the increasing interest in pharmacological interventions to stimulate BAT in human subjects. NTR 2473.

  14. Washout Ratio in the Hepatic Vein Measured by Contrast-Enhanced Ultrasonography to Distinguish Between Inflammatory and Noninflammatory Hepatic Disorders in Dogs.

    Science.gov (United States)

    Morishita, K; Hiramoto, A; Michishita, A; Takagi, S; Osuga, T; Lim, S Y; Nakamura, K; Sasaki, N; Ohta, H; Takiguchi, M

    2017-05-01

    Perflubutane microbubbles, a second-generation ultrasound contrast agent, are phagocytized by Kupffer cells. This characteristic may be useful to differentiate diffuse hepatic diseases in dogs. To determine whether the washout ratio in the hepatic vein (HV) measured by contrast-enhanced ultrasonography (CEUS) can distinguish between inflammatory and noninflammatory hepatic disorders in dogs. Forty-one client-owned dogs with hepatic disorders including 14 with hepatitis, 7 with primary hypoplasia of the portal vein (PHPV), 9 with congenital portosystemic shunt (cPSS), and 11 with other hepatopathy were enrolled. Six dogs without hepatic disease also were evaluated as healthy controls. Dogs with hepatic disorders were prospectively included. Contrast-enhanced ultrasonography of the HV was performed for 2 minutes. Washout ratio was defined as the attenuation rate from peak intensity to the intensity at the end of the CEUS study. Washout ratio in the hepatitis group (median, 18.0%; range, 2.0-37.0%) was significantly lower than that of the PHPV (median, 52.2%; range, 11.5-86.3%), cPSS (median, 60.0%; range, 28.6-77.4%), other hepatopathy (median, 70.5%; range, 26.6-88.4%), and normal (median, 78.0%; range, 60.7-91.7%) groups. The area under the receiver operating characteristic curve for hepatitis was 0.960, with a 95% confidence interval (CI) of 0.853-0.990. Washout ratio ≤37.1% resulted in a sensitivity of 100% (95% CI, 78.5-100%) and specificity of 85.2% (95% CI, 67.5-94.1%) for the prediction of hepatitis. Washout ratio can distinguish hepatitis from the other noninflammatory disorders with high accuracy. This result might reflect impaired Kupffer cell phagocytosis in dogs with hepatitis. Copyright © 2017 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals, Inc. on behalf of the American College of Veterinary Internal Medicine.

  15. A Statistical Method and Tool to Account for Indirect Calorimetry Differential Measurement Error in a Single-Subject Analysis.

    Science.gov (United States)

    Tenan, Matthew S

    2016-01-01

    Indirect calorimetry and oxygen consumption (VO2) are accepted tools in human physiology research. It has been shown that indirect calorimetry systems exhibit differential measurement error, where the error of a device is systematically different depending on the volume of gas flow. Moreover, systems commonly report multiple decimal places of precision, giving the clinician a false sense of device accuracy. The purpose of this manuscript is to demonstrate the use of a novel statistical tool which models the reliability of two specific indirect calorimetry systems, Douglas bag and Parvomedics 2400 TrueOne, as univariate normal distributions and implements the distribution overlapping coefficient to determine the likelihood that two VO2 measures are the same. A command line implementation of the tool is available for the R programming language as well as a web-based graphical user interface (GUI). This tool is valuable for clinicians performing a single-subject analysis as well as researchers interested in determining if their observed differences exceed the error of the device.

  16. Exercise responsive genes measured in peripheral blood of women with chronic fatigue syndrome and matched control subjects.

    Science.gov (United States)

    Whistler, Toni; Jones, James F; Unger, Elizabeth R; Vernon, Suzanne D

    2005-03-24

    Chronic fatigue syndrome (CFS) is defined by debilitating fatigue that is exacerbated by physical or mental exertion. To search for markers of CFS-associated post-exertional fatigue, we measured peripheral blood gene expression profiles of women with CFS and matched controls before and after exercise challenge. Women with CFS and healthy, age-matched, sedentary controls were exercised on a stationary bicycle at 70% of their predicted maximum workload. Blood was obtained before and after the challenge, total RNA was extracted from mononuclear cells, and signal intensity of the labeled cDNA hybridized to a 3800-gene oligonucleotide microarray was measured. We identified differences in gene expression among and between subject groups before and after exercise challenge and evaluated differences in terms of Gene Ontology categories. Exercise-responsive genes differed between CFS patients and controls. These were in genes classified in chromatin and nucleosome assembly, cytoplasmic vesicles, membrane transport, and G protein-coupled receptor ontologies. Differences in ion transport and ion channel activity were evident at baseline and were exaggerated after exercise, as evidenced by greater numbers of differentially expressed genes in these molecular functions. These results highlight the potential use of an exercise challenge combined with microarray gene expression analysis in identifying gene ontologies associated with CFS.

  17. Exercise responsive genes measured in peripheral blood of women with Chronic Fatigue Syndrome and matched control subjects

    Directory of Open Access Journals (Sweden)

    Unger Elizabeth R

    2005-03-01

    Full Text Available Abstract Background Chronic fatigue syndrome (CFS is defined by debilitating fatigue that is exacerbated by physical or mental exertion. To search for markers of CFS-associated post-exertional fatigue, we measured peripheral blood gene expression profiles of women with CFS and matched controls before and after exercise challenge. Results Women with CFS and healthy, age-matched, sedentary controls were exercised on a stationary bicycle at 70% of their predicted maximum workload. Blood was obtained before and after the challenge, total RNA was extracted from mononuclear cells, and signal intensity of the labeled cDNA hybridized to a 3800-gene oligonucleotide microarray was measured. We identified differences in gene expression among and between subject groups before and after exercise challenge and evaluated differences in terms of Gene Ontology categories. Exercise-responsive genes differed between CFS patients and controls. These were in genes classified in chromatin and nucleosome assembly, cytoplasmic vesicles, membrane transport, and G protein-coupled receptor ontologies. Differences in ion transport and ion channel activity were evident at baseline and were exaggerated after exercise, as evidenced by greater numbers of differentially expressed genes in these molecular functions. Conclusion These results highlight the potential use of an exercise challenge combined with microarray gene expression analysis in identifying gene ontologies associated with CFS.

  18. Measuring cognitive load during simulation-based psychomotor skills training: sensitivity of secondary-task performance and subjective ratings.

    Science.gov (United States)

    Haji, Faizal A; Khan, Rabia; Regehr, Glenn; Drake, James; de Ribaupierre, Sandrine; Dubrowski, Adam

    2015-12-01

    As interest in applying cognitive load theory (CLT) to the study and design of pedagogic and technological approaches in healthcare simulation grows, suitable measures of cognitive load (CL) are needed. Here, we report a two-phased study investigating the sensitivity of subjective ratings of mental effort (SRME) and secondary-task performance (signal detection rate, SDR and recognition reaction time, RRT) as measures of CL. In phase 1 of the study, novice learners and expert surgeons attempted a visual-monitoring task under two conditions: single-task (monitoring a virtual patient's heart-rate) and dual-task (tying surgical knots on a bench-top simulator while monitoring the virtual patient's heart-rate). Novices demonstrated higher mental effort and inferior secondary-task performance on the dual-task compared to experts (RRT 1.76 vs. 0.73, p = 0.012; SDR 0.27 vs. 0.97, p instructional design research are discussed.

  19. Myocardial blood flow at rest and stress measured with dynamic contrast-enhanced MRI: comparison of a distributed parameter model with a Fermi function model.

    Science.gov (United States)

    Broadbent, David A; Biglands, John D; Larghat, Abdulghani; Sourbron, Steven P; Radjenovic, Aleksandra; Greenwood, John P; Plein, Sven; Buckley, David L

    2013-12-01

    To assess the feasibility of simultaneously measuring blood flow (Fb ), Gd-DTPA extraction fraction (E), and distribution volume (vd ) in healthy myocardium at rest and under adenosine stress using dynamic contrast-enhanced MRI. Sixteen volunteers were examined at 1.5 T and 11 returned for a repeat study. The data were analyzed using a distributed parameter (DP) 2-region model to arrive at estimates of Fb , E, blood volume, and interstitial volume. For comparison, estimates of Fb were also obtained using a Fermi function model. DP model fits were successful in 49 of the 54 data sets. Estimates obtained using DP and Fermi models did not differ for either rest Fb or myocardial perfusion reserve though DP estimates of stress Fb were lower than Fermi estimates. The repeatability of the DP parameters Fb , E, and vd was better than or equal to the repeatability of Fermi-Fb . E at rest and under stress was estimated to be 66% and 57%, respectively. The results suggest that characteristics of the microvasculature of healthy myocardium can be reliably determined using dynamic contrast-enhanced MRI at rest and under stress and that delivery of Gd-DTPA to the myocardium is not flow-limited. Copyright © 2013 Wiley Periodicals, Inc.

  20. On the Use of Molecular Weight Cutoff Cassettes to Measure Dynamic Relaxivity of Novel Gadolinium Contrast Agents: Example Using Hyaluronic Acid Polymer Complexes in Phosphate-Buffered Saline

    Directory of Open Access Journals (Sweden)

    Nima Kasraie

    2011-01-01

    Full Text Available The aims of this study were to determine whether standard extracellular contrast agents of Gd(III ions in combination with a polymeric entity susceptible to hydrolytic degradation over a finite period of time, such as Hyaluronic Acid (HA, have sufficient vascular residence time to obtain comparable vascular imaging to current conventional compounds and to obtain sufficient data to show proof of concept that HA with Gd-DTPA ligands could be useful as vascular imaging agents. We assessed the dynamic relaxivity of the HA bound DTPA compounds using a custom-made phantom, as well as relaxation rates at 10.72 MHz with concentrations ranging between 0.09 and 7.96 mM in phosphate-buffered saline. Linear dependences of static longitudinal relaxation rate (R1 on concentration were found for most measured samples, and the HA samples continued to produce high signal strength after 24 hours after injection into a dialysis cassette at 3T, showing superior dynamic relaxivity values compared to conventional contrast media such as Gd-DTPA-BMA.

  1. Using a multi-feature paradigm to measure mismatch responses to minimal sound contrasts in children with cochlear implants and hearing aids.

    Science.gov (United States)

    Uhlén, Inger; Engström, Elisabet; Kallioinen, Petter; Nakeva von Mentzer, Cecilia; Lyxell, Björn; Sahlén, Birgitta; Lindgren, Magnus; Ors, Marianne

    2017-10-01

    Our aim was to explore whether a multi-feature paradigm (Optimum-1) for eliciting mismatch negativity (MMN) would objectively capture difficulties in perceiving small sound contrasts in children with hearing impairment (HI) listening through their hearing aids (HAs) and/or cochlear implants (CIs). Children aged 5-7 years with HAs, CIs and children with normal hearing (NH) were tested in a free-field setting using a multi-feature paradigm with deviations in pitch, intensity, gap, duration, and location. There were significant mismatch responses across all subjects that were positive (p-MMR) for the gap and pitch deviants (F(1,43) = 5.17, p = 0.028 and F(1,43) = 6.56, p = 0.014, respectively) and negative (MMN) for the duration deviant (F(1,43) = 4.74, p = 0.035). Only the intensity deviant showed a significant group interaction with MMN in the HA group and p-MMR in the CI group (F(2,43) = 3.40, p = 0.043). The p-MMR correlated negatively with age, with the strongest correlation in the NH subjects. In the CI group, the late discriminative negativity (LDN) was replaced by a late positivity with a significant group interaction for the location deviant. Children with severe HI can be assessed through their hearing device with a fast multi-feature paradigm. For further studies a multi-feature paradigm including more complex speech sounds may better capture variation in auditory processing in these children. © 2017 Scandinavian Psychological Associations and John Wiley & Sons Ltd.

  2. Brain capillary transit time heterogeneity in healthy volunteers measured by dynamic contrast-enhanced T1-weighted perfusion MRI

    DEFF Research Database (Denmark)

    Larsson, Henrik B.W.; Vestergaard, Mark B.; Lindberg, Ulrich

    2017-01-01

    based on a gamma-variate model of the capillary transit time distribution. In addition, we wanted to investigate if a subtle increase of the blood–brain barrier permeability can be incorporated into the model, still allowing estimation of CTH. Materials and Methods: Twenty-three healthy subjects were...... scanned at 3.0T MRI system applying DCE-MRI and using a gamma-variate model to estimate CTH as well as cerebral blood flow (CBF), cerebral blood volume (CBV), and permeability of the blood–brain barrier, measured as the influx constant Ki. For proof of principle we also investigated three patients...

  3. Contrast Time-Density Time on Digital Subtraction Angiography Correlates With Cerebral Arteriovenous Malformation Flow Measured by Quantitative Magnetic Resonance Angiography, Angioarchitecture, and Hemorrhage.

    Science.gov (United States)

    Brunozzi, Denise; Hussein, Ahmed E; Shakur, Sophia F; Linninger, Andreas; Hsu, Chih-Yang; Charbel, Fady T; Alaraj, Ali

    2017-07-06

    Digital subtraction angiography (DSA) currently provides angioarchitectural features of cerebral arteriovenous malformations (AVMs) but its role in the hemodynamic evaluation of AVMs is poorly understood. To assess contrast time-density time (TT) on DSA relative to AVM flow measured using quantitative magnetic resonance angiography (QMRA). Patients seen at our institution between 2007 and 2014 with a supratentorial AVM and DSA and QMRA obtained prior to any treatment were retrospectively reviewed. Regions of interest were selected on the draining veins at the point closest to the nidus. TT on DSA was defined as time needed for contrast to change image intensity from 10% to 100%, 100% to 10%, and 25% to 25%. TT was correlated to AVM total flow, angioarchitectural features, and hemorrhage. Twenty-eight patients (mean age 35.6 yr) were included. Six patients presented with hemorrhage. Mean AVM volume was 11.42 mL (range 0.3-57.7 mL). Higher total AVM flow significantly correlated with shorter TT 100%-10% and TT 25%-25% ( P = .02, .02, respectively). Presence of venous stenosis correlated significantly with shorter TT 100%-10% ( P = .04) and TT 25%-25% ( P = .04). AVMs with a single draining vein exhibited longer TT 25%-25% compared to those with multiple draining veins ( P = .04). Ruptured AVMs had significantly shorter TT 10%-100% compared to unruptured AVMs ( P = .05). TT on DSA correlates with cerebral AVM flow measured using QMRA and with AVM angioarchitecture and hemorrhagic presentation. Thus, TT may be used to indirectly estimate AVM flow during angiography in real-time and may also be an indicator of important AVM characteristics associated with outflow resistance and increased rupture risk, such as venous stenosis.

  4. Images perceived after chromatic or achromatic contrast sensitivity losses.

    Science.gov (United States)

    Luque, M José; Capilla, Pascual; de Fez, M Dolores; García-Domene, M Carmen

    2010-05-01

    We simulate how subjects with losses in chromatic and achromatic contrast sensitivity perceive colored images by using the spatiochromatic corresponding pair algorithm. This is a generalized version of the algorithm by Capilla et al. (J Opt Soc Am (A) 2004;21:176-186) for simulating color perception of color deviant subjects, which incorporates a simple spatial vision model, consisting of a linear filtering stage, with a band-pass achromatic filter and two low-pass chromatic ones, for the red-green and blue-yellow mechanisms. These filters, except for the global scaling, are the subject's contrast sensitivity functions measured along the cardinal directions of the color space. In its present form, the algorithm would serve to simulate alterations both in the spectral sensitivities and in the contrast sensitivities of the visual mechanisms. After a preliminary theoretical study on the effect of frequency selective and overall reductions in the contrast sensitivity function of a single mechanism, we present cases of real subjects with glaucoma and diabetes, suffering alterations of different magnitude in the three mechanisms. The simulations allow us to learn about the different types of distortions that can be experienced by a subject with impaired contrast sensitivities (blur, haloes, color shifts, local or global contrast, brightness and colorfulness reductions, etc.) and highlight the difficulties arising when trying to predict the quality of the final image from the losses in the individual mechanisms.

  5. Objective and subjective measures of sleepiness, and their associations with on-road driving events in shift workers.

    Science.gov (United States)

    Ftouni, Suzanne; Sletten, Tracey L; Howard, Mark; Anderson, Clare; Lenné, Michael G; Lockley, Steven W; Rajaratnam, Shantha M W

    2013-02-01

    To assess the relationships between sleepiness and the incidence of adverse driving events in nurses commuting to and from night and rotating shifts, 27 rotating and permanent night shift-working nurses were asked to complete daily sleep and duty logs, and wear wrist-activity monitors for 2 weeks (369 driving sessions). During all commutes, ocular measures of drowsiness, including the Johns Drowsiness Scale score, were assessed using the Optalert™ system. Participants self-reported their subjective sleepiness at the beginning and end of each drive, and any events that occurred during the drive. Rotating shift nurses reported higher levels of sleepiness compared with permanent night shift nurses. In both shift-working groups, self-reported sleepiness, drowsiness and drive events were significantly higher during commutes following night shifts compared with commutes before night shifts. Strong associations were found between objective drowsiness and increased odds of driving events during commutes following night shifts. Maximum total blink duration (mean = 7.96 s) during the drive and pre-drive Karolinska Sleepiness Scale (mean = 5.0) were associated with greater incidence of sleep-related events [OR, 5.35 (95% CI, 1.32, 21.60), OR, 1.69 (95% CI, 1.04, 2.73), respectively]. Inattention was strongly associated with a Johns Drowsiness Scale score equal to or above 4.5 [OR, 4.58 (95% CI, 1.26-16.69)]. Hazardous driving events were more likely to occur when drivers had been awake for 16 h or more [OR, 4.50 (95% CI, 1.81, 11.16)]. Under real-world driving conditions, shift-working nurses experience high levels of drowsiness as indicated by ocular measures, which are associated with impaired driving performance following night shift work. © 2012 European Sleep Research Society.

  6. Simultaneous measurement of kidney function by dynamic contrast enhanced MRI and FITC-sinistrin clearance in rats at 3 tesla: initial results.

    Directory of Open Access Journals (Sweden)

    Frank G Zöllner

    Full Text Available Glomerular filtration rate (GFR is an essential parameter of kidney function which can be measured by dynamic contrast enhanced magnetic resonance imaging (MRI-GFR and transcutaneous approaches based on fluorescent tracer molecules (optical-GFR. In an initial study comparing both techniques in separate measurements on the same animal, the correlation of the obtained GFR was poor. The goal of this study was to investigate if a simultaneous measurement was feasible and if thereby, the discrepancies in MRI-GFR and optical-GFR could be reduced. For the experiments healthy and unilateral nephrectomised (UNX Sprague Dawley (SD rats were used. The miniaturized fluorescent sensor was fixed on the depilated back of an anesthetized rat. A bolus of 5 mg/100 g b.w. of FITC-sinistrin was intravenously injected. For dynamic contrast enhanced perfusion imaging (DCE-MRI a 3D time-resolved angiography with stochastic trajectories (TWIST sequence was used. By means of a one compartment model the excretion half-life (t1/2 of FITC-sinistrin was calculated and converted into GFR. GFR from DCE-MRI was calculated by fitting pixel-wise a two compartment renal filtration model. Mean cortical GFR and GFR by FITC-sinistrin were compared by Bland-Altman plots and pair-wise t-test. Results show that a simultaneous GFR measurement using both techniques is feasible. Mean optical-GFR was 4.34 ± 2.22 ml/min (healthy SD rats and 2.34 ± 0.90 ml/min (UNX rats whereas MRI-GFR was 2.10 ± 0.64 ml/min (SD rats and 1.17 ± 0.38 ml/min (UNX rats. Differences between healthy and UNX rats were significant (p<0.05 and almost equal percentage difference (46.1% and 44.3% in mean GFR were assessed with both techniques. Overall mean optical-GFR values were approximately twice as high compared to MRI-GFR values. However, compared to a previous study, our results showed a higher agreement. In conclusion, the possibility to use the transcutaneous method in MRI may have a huge impact in

  7. Poachers and Poverty: Assessing Objective and Subjective Measures of Poverty among Illegal Hunters Outside Ruaha National Park, Tanzania

    Directory of Open Access Journals (Sweden)

    Eli J Knapp

    2017-01-01

    Full Text Available Illegal hunters in Africa may be making rational decisions about the hunting activities they partake in. These decisions could be linked to their socioeconomic status and the livelihood opportunities available to them. In particular, poverty is widely considered the leading driver that causes a household's inhabitants to take up poaching in protected areas. Programs aiming to protect vulnerable wildlife populations by mitigating poaching have historically relied upon income-based poverty metrics in efforts to reduce regional poverty and incentivise local inhabitants to discontinue poaching activities. Because such data sets that deal with poachers directly are rare, assumptions about the role of poverty, and the extent of poverty, that drives poaching have been hard to test. This study uses a unique sample of 173 self-admitted poachers living in villages adjacent to Ruaha National Park in Tanzania to explore the influence of poverty on poaching. Results indicated high demographic and household economy heterogeneity among poaching households. Capability deprivation examined more subjective measures of poverty and revealed that poachers are strongly motivated by the need to improve their incomes, but are not necessarily the poorest of the poor.

  8. Apolipoprotein E gene polymorphism and its effect on anthropometric measures in normoglycemic subjects and type 2 diabetes

    Directory of Open Access Journals (Sweden)

    Tabatabaei-Malazy Ozra

    2012-10-01

    Full Text Available Abstract Background Apolipoprotein E (apo E plays a major role in lipid metabolism, obesity and accordingly in development of diabetes and coronary heart disease (CHD. Our main objective was to evaluate the association between apo E gene polymorphism with anthropometric measures. Methods Participants were selected from zone 17 Tehran/Iran. We assessed height, weight, body mass index (BMI, waist circumference (WC, blood pressure, serum fasting blood sugar, total cholesterol and triglycerides. Genotyping for apo E gene polymorphism was carried out using PCR-RFLP technique. Results Among total study population (n=311, 156 subjects were diabetic. The apo E3/E3 was the most common genotype in our population while E2 and E4 alleles had lower frequencies, respectively. After adjustment for diabetes, the apo E2 and E4 alleles were significantly associated with hypercholesterolemia and WC, respectively (p= 0.009, 0.034. This association was also related to sex and age. The probability of having abdominal obesity in E4 allele carriers was increased from 0.22 to 8.12 in women and to 3.08 in age ≥ 50 years. Conclusions Apo E polymorphism had significant influences on WC and total cholesterol level in patients with type 2 diabetes. This study highlights the importance of lifestyle modifications which may be more beneficial in hypercholesterolemic women carriers of E2 and E4 alleles concomitant central obesity.

  9. Contrast Invariant SNR

    DEFF Research Database (Denmark)

    Weiss, Pierre; Escande, Paul; Dong, Yiqiu

    We design an image quality measure independent of local contrast changes, which constitute simple models of illumination changes. Given two images, the algorithm provides the image closest to the first one with the component tree of the second. This problem can be cast as a specific convex program...

  10. Mobile app Aston contrast sensitivity test.

    Science.gov (United States)

    Kingsnorth, Alec; Drew, Tom; Grewal, Bikramjit; Wolffsohn, James S

    2016-07-01

    Contrast detection is an important aspect of the assessment of visual function; however, clinical tests evaluate limited spatial frequencies and contrasts. This study validates the accuracy and inter-test repeatability of a swept-frequency near and distance mobile app Aston contrast sensitivity test, which overcomes this limitation compared to traditional charts. Twenty subjects wearing their full refractive correction underwent contrast sensitivity testing on the new near application (near app), distance app, CSV-1000 and Pelli-Robson charts with full correction and with vision degraded by 0.8 and 0.2 Bangerter degradation foils. In addition repeated measures using the 0.8 occluding foil were taken. The mobile apps (near more than distance, p = 0.005) recorded a higher contrast sensitivity than printed tests (p  0.05). Although the coefficient of repeatability was lowest for the Pelli-Robson charts (0.14 log units), the mobile app charts measured more spatial frequencies, took less time and were more repeatable (near: 0.26 to 0.37 log units; distance: 0.34 to 0.39 log units) than the CSV-1000 (0.30 to 0.93 log units). The duration to complete the CSV-1000 was 124 ± 37 seconds, Pelli-Robson 78 ± 27 seconds, near app 53 ± 15 seconds and distance app 107 ± 36 seconds. While there were differences between charts in contrast levels measured, the new Aston near and distance apps are valid, repeatable and time-efficient method of assessing contrast sensitivity at multiple spatial frequencies. © 2016 Optometry Australia.

  11. Measurement of extracellular volume and transit time heterogeneity using contrast-enhanced myocardial perfusion MRI in patients after acute myocardial infarction.

    Science.gov (United States)

    Kunze, Karl P; Rischpler, Christoph; Hayes, Carmel; Ibrahim, Tareq; Laugwitz, Karl-Ludwig; Haase, Axel; Schwaiger, Markus; Nekolla, Stephan G

    2017-06-01

    To assess the ability of dynamic contrast-enhanced myocardial perfusion MRI to measure extracellular volume (ECV) and to investigate the possibility of estimating capillary transit time heterogeneity (CTH) in patients after myocardial infarction and successful revascularization. Twenty-four perfusion data sets were acquired on a 3 Tesla positron emission tomography (PET)/MRI scanner. Three perfusion models of different complexity were implemented in a hierarchical fashion with an Akaike information criterion being used to determine the number of fit parameters supported by the data. Results were compared sector-wise to ECV from an equilibrium T1 mapping method (modified look-locker inversion recovery (MOLLI)). ECV derived from the perfusion analysis correlated well with equilibrium measurements (R² = 0.76). Estimation of CTH was supported in 16% of sectors (mostly remote). Inclusion of a nonzero CTH parameter usually led to lower estimates of first-pass extraction and slightly higher estimates of blood volume and flow. Estimation of the capillary permeability-surface area product was feasible in 81% of sectors. Transit time heterogeneity has a measurable effect on the kinetic analysis of myocardial perfusion MRI data, and Gd-DTPA extravasation in the myocardium is usually not flow-limited in infarct-related pathology. Measurement of myocardial ECV using perfusion imaging could provide a scan-time efficient alternative to methods based on T1 mapping. Magn Reson Med 77:2320-2330, 2017. © 2016 International Society for Magnetic Resonance in Medicine. © 2016 International Society for Magnetic Resonance in Medicine.

  12. Phase-Contrast MRI measurements in intra-cranial aneurysms in-vivo of flow patterns, velocity fields and wall shear stress: A comparison with CFD

    Science.gov (United States)

    Boussel, Loic; Rayz, Vitaliy; Martin, Alastair; Acevedo-Bolton, Gabriel; Lawton, Michael T.; Higashida, Randall; Smith, Wade S.; Young, William L.; Saloner, David

    2010-01-01

    Evolution of intracranial aneurysms is known to be related to hemodynamic forces such as Wall Shear Stress (WSS) and Maximum Shear Stress (MSS). Estimation of these parameters can be performed using numerical simulations (computational fluid dynamics - CFD) but can also be directly measured with MRI using a time-dependent 3D phase-contrast sequence with encoding of each of the three components of the velocity vectors (7D-MRV). In order to study the accuracy of 7D-MRV in estimating these parameters in–vivo, in comparison with CFD, 7D-MRV and patient-specific CFD modeling was performed for three patients who had intracranial aneurysms. A visual and a quantitative analysis of the flow pattern and the distribution of velocities, MSS, and WSS were performed between the two techniques. Spearman's coefficients of correlation between the two techniques were 0.56 for the velocity field, 0.48 for MSS and 0.59 for WSS. Visual analysis and Bland-Altman plots showed a good agreement for flow pattern and velocities but large discrepancies for MSS and WSS. In conclusion, these results indicate that in-vivo 7D-MRV can be used to measure velocity flow fields and to estimate MSS and WSS but is not currently able to provide accurate quantification of these two last parameters. PMID:19161132

  13. Measurements of ion cyclotron range of frequencies mode converted wave intensity with phase contrast imaging in Alcator C-Mod and comparison with full-wave simulations

    Energy Technology Data Exchange (ETDEWEB)

    Tsujii, N.; Porkolab, M.; Bonoli, P. T.; Lin, Y.; Wright, J. C.; Wukitch, S. J. [MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139 (United States); Jaeger, E. F. [XCEL Engineering, Inc., Oak Ridge, Tennessee 37830 (United States); Green, D. L. [Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Harvey, R. W. [CompX, Del Mar, California 92014 (United States)

    2012-08-15

    Radio frequency waves in the ion cyclotron range of frequencies (ICRF) are widely used to heat tokamak plasmas. In ICRF heating schemes involving multiple ion species, the launched fast waves convert to ion cyclotron waves or ion Bernstein waves at the two-ion hybrid resonances. Mode converted waves are of interest as actuators to optimise plasma performance through current drive and flow drive. In order to describe these processes accurately in a realistic tokamak geometry, numerical simulations are essential, and it is important that these codes be validated against experiment. In this study, the mode converted waves were measured using a phase contrast imaging technique in D-H and D-{sup 3}He plasmas. The measured mode converted wave intensity in the D-{sup 3}He mode conversion regime was found to be a factor of {approx}50 weaker than the full-wave predictions. The discrepancy was reduced in the hydrogen minority heating regime, where mode conversion is weaker.

  14. Paying Hypertension Research Subjects

    Science.gov (United States)

    Casarett, David; Karlawish, Jason; Asch, David A

    2002-01-01

    CONTEXT Cash payments are often used to compensate subjects who participate in research. However, ethicists have argued that these payments might constitute an undue inducement. OBJECTIVES To determine whether potential subjects agree with theoretical arguments that a payment could be an undue inducement. DESIGN/SETTING/PARTICIPANTS Survey of 350 prospective jurors. MAIN OUTCOME MEASURES Belief that a $500 payment for research participation would impair their own, and others' ability to think carefully about the risks and benefits of a clinical trial. RESULTS Two hundred sixty-one jurors (74.6%) believed that a $500 payment would impair subjects' ability to think carefully about the risks and benefits of research. Ninety-six of 120 (80%) expressed this concern about subjects with a low income ($50,000). In contrast, only 69 (19.7%) of jurors believed that a $500 payment would influence them. Jurors who believed that this payment would influence them reported lower incomes and less education. CONCLUSION Members of the general public share ethical concerns about the influence of payments for research, although they believe that these concerns are more applicable to others than to themselves.

  15. Investigation of dynamic SPECT measurements of the arterial input function in human subjects using simulation, phantom and human studies.

    Science.gov (United States)

    Winant, Celeste D; Aparici, Carina Mari; Zelnik, Yuval R; Reutter, Bryan W; Sitek, Arkadiusz; Bacharach, Stephen L; Gullberg, Grant T

    2012-01-21

    Computer simulations, a phantom study and a human study were performed to determine whether a slowly rotating single-photon computed emission tomography (SPECT) system could provide accurate arterial input functions for quantification of myocardial perfusion imaging using kinetic models. The errors induced by data inconsistency associated with imaging with slow camera rotation during tracer injection were evaluated with an approach called SPECT/P (dynamic SPECT from positron emission tomography (PET)) and SPECT/D (dynamic SPECT from database of SPECT phantom projections). SPECT/P simulated SPECT-like dynamic projections using reprojections of reconstructed dynamic (94)Tc-methoxyisobutylisonitrile ((94)Tc-MIBI) PET images acquired in three human subjects (1 min infusion). This approach was used to evaluate the accuracy of estimating myocardial wash-in rate parameters K(1) for rotation speeds providing 180° of projection data every 27 or 54 s. Blood input and myocardium tissue time-activity curves (TACs) were estimated using spatiotemporal splines. These were fit to a one-compartment perfusion model to obtain wash-in rate parameters K(1). For the second method (SPECT/D), an anthropomorphic cardiac torso phantom was used to create real SPECT dynamic projection data of a tracer distribution derived from (94)Tc-MIBI PET scans in the blood pool, myocardium, liver and background. This method introduced attenuation, collimation and scatter into the modeling of dynamic SPECT projections. Both approaches were used to evaluate the accuracy of estimating myocardial wash-in parameters for rotation speeds providing 180° of projection data every 27 and 54 s. Dynamic cardiac SPECT was also performed in a human subject at rest using a hybrid SPECT/CT scanner. Dynamic measurements of (99m)Tc-tetrofosmin in the myocardium were obtained using an infusion time of 2 min. Blood input, myocardium tissue and liver TACs were estimated using the same spatiotemporal splines. The

  16. Investigation of dynamic SPECT measurements of the arterial input function in human subjects using simulation, phantom and human studies

    Science.gov (United States)

    Winant, Celeste D.; Aparici, Carina Mari; Zelnik, Yuval R.; Reutter, Bryan W.; Sitek, Arkadiusz; Bacharach, Stephen L.; Gullberg, Grant T.

    2012-01-01

    Computer simulations, a phantom study and a human study were performed to determine whether a slowly rotating single-photon computed emission tomography (SPECT) system could provide accurate arterial input functions for quantification of myocardial perfusion imaging using kinetic models. The errors induced by data inconsistency associated with imaging with slow camera rotation during tracer injection were evaluated with an approach called SPECT/P (dynamic SPECT from positron emission tomography (PET)) and SPECT/D (dynamic SPECT from database of SPECT phantom projections). SPECT/P simulated SPECT-like dynamic projections using reprojections of reconstructed dynamic 94Tc-methoxyisobutylisonitrile (94Tc-MIBI) PET images acquired in three human subjects (1 min infusion). This approach was used to evaluate the accuracy of estimating myocardial wash-in rate parameters K1 for rotation speeds providing 180° of projection data every 27 or 54 s. Blood input and myocardium tissue time-activity curves (TACs) were estimated using spatiotemporal splines. These were fit to a one-compartment perfusion model to obtain wash-in rate parameters K1. For the second method (SPECT/D), an anthropomorphic cardiac torso phantom was used to create real SPECT dynamic projection data of a tracer distribution derived from 94Tc-MIBI PET scans in the blood pool, myocardium, liver and background. This method introduced attenuation, collimation and scatter into the modeling of dynamic SPECT projections. Both approaches were used to evaluate the accuracy of estimating myocardial wash-in parameters for rotation speeds providing 180° of projection data every 27 and 54 s. Dynamic cardiac SPECT was also performed in a human subject at rest using a hybrid SPECT/CT scanner. Dynamic measurements of 99mTc-tetrofosmin in the myocardium were obtained using an infusion time of 2 min. Blood input, myocardium tissue and liver TACs were estimated using the same spatiotemporal splines. The spatiotemporal maximum

  17. Physical activity and sedentary behavior measured objectively and subjectively in overweight and obese adults with schizophrenia or schizoaffective disorders.

    Science.gov (United States)

    Janney, Carol A; Ganguli, Rohan; Tang, Gong; Cauley, Jane A; Holleman, Robert G; Richardson, Caroline R; Kriska, Andrea M

    2015-10-01

    Describe objective and subjective physical activity levels and time spent being sedentary in adults with schizophrenia or schizoaffective disorders (SZO/SA). Baseline physical activity and sedentary behaviors were assessed among 46 overweight and obese community-dwelling adults (aged 18-70 years; BMI > 27 kg/m(2)) diagnosed with SZO/SA by DSM-IV-TR, with mild symptom severity (Positive and Negative Syndrome Scale score physical activity levels, measured using actigraphs, in WAIST were compared to a nationally representative sample of users (n = 46) and nonusers (n = 46) of mental health service (MHS) from the National Health and Nutrition Examination Survey (NHANES 2003-2004) matched by sex, BMI, and age. On average, adults with SZO/SA wore actigraphs more than 15 h/d for 7 days averaging 151,000 counts/d. The majority of monitoring time (81%) was classified as sedentary (approximately 13 h/d). Moderate/vigorous and light physical activity accounted for only 2% (19 min/d) and 17% (157 min/d) of monitoring time/d, respectively. Primary source of activity was household activities (409 ± 438 min/wk). Fifty-three percent reported walking for transportation or leisure. Adults with SZO/SA were significantly less active (176 min/d) and more sedentary (756 min/d) than NHANES users of MHS (293 and 640 min/d, respectively) and nonusers of MHS (338 and 552 min/d, respectively) (P physical activity; and significantly less active than NHANES users and nonusers of MHS. This sedentary lifestyle is significantly lower than those of other inactive US populations, is costly for the individual and community, and highlights the need for physical activity promotion and interventions in this high risk population. © Copyright 2015 Physicians Postgraduate Press, Inc.

  18. Substance use, trait measures, and subjective response to nicotine in never-smokers stratified on parental smoking history and sex.

    Science.gov (United States)

    Pomerleau, Ovide F; Pomerleau, Cynthia S; Snedecor, Sandy M; Finkenauer, Raphaela; Mehringer, Ann M; Langenecker, Scott A; Sirevaag, Erik J

    2009-09-01

    Male and female never-smokers stratified on parental history of smoking were tested for possible differences in susceptibility to the hedonic effects of nicotine. We recruited nicotine-exposed never-smokers with two never-smoking biological parents (PH-) or two ever-smoking biological parents (PH+). After completing a baseline assessment battery focusing on conditions or behaviors associated with smoking, participants were tested for subjective and hedonic effects in response to administration of three different nicotine doses (0.0, 0.5, and 1.0 mg) via nasal spray. Physiological and biochemical reactivity also was monitored. PH+ were significantly more likely to report having experienced a "buzz" upon early smoking experimentation and to have histories of alcohol abuse and alcoholism; they also scored higher on disordered eating. In response to nicotine dosing, PH+ reported an increase in depressed mood, compared with a minimal response in PH-, in keeping with our expectation that nicotine would have more pronounced effects in PH+. Regardless of parental history, women reported experiencing greater anxiety in response to the highest nicotine dose, compared with men. Further exploration in larger samples, using more stringent selection criteria, a wider range of measures, and a less aversive dosing method, may provide a full test of the possible utility of the parental history model for illuminating biobehavioral mechanisms underlying response to nicotine. Also important would be broadening the scope of inquiry to include comparisons with ever-smokers to determine what protected PH+ from becoming smokers, despite the presence of factors that might be expected to decrease resilience and increase susceptibility.

  19. Repeatability of quantitative FDG-PET/CT and contrast-enhanced CT in recurrent ovarian carcinoma: test-retest measurements for tumor FDG uptake, diameter, and volume.

    Science.gov (United States)

    Rockall, Andrea G; Avril, Norbert; Lam, Raymond; Iannone, Robert; Mozley, P David; Parkinson, Christine; Bergstrom, Donald; Sala, Evis; Sarker, Shah-Jalal; McNeish, Iain A; Brenton, James D

    2014-05-15

    Repeatability of baseline FDG-PET/CT measurements has not been tested in ovarian cancer. This dual-center, prospective study assessed variation in tumor 2[18F]fluoro-2-deoxy-D-glucose (FDG) uptake, tumor diameter, and tumor volume from sequential FDG-PET/CT and contrast-enhanced computed tomography (CECT) in patients with recurrent platinum-sensitive ovarian cancer. Patients underwent two pretreatment baseline FDG-PET/CT (n = 21) and CECT (n = 20) at two clinical sites with different PET/CT instruments. Patients were included if they had at least one target lesion in the abdomen with a standardized uptake value (SUV) maximum (SUVmax) of ≥ 2.5 and a long axis diameter of ≥ 15 mm. Two independent reading methods were used to evaluate repeatability of tumor diameter and SUV uptake: on site and at an imaging clinical research organization (CRO). Tumor volume reads were only performed by CRO. In each reading set, target lesions were independently measured on sequential imaging. Median time between FDG-PET/CT was two days (range 1-7). For site reads, concordance correlation coefficients (CCC) for SUVmean, SUVmax, and tumor diameter were 0.95, 0.94, and 0.99, respectively. Repeatability coefficients were 16.3%, 17.3%, and 8.8% for SUVmean, SUVmax, and tumor diameter, respectively. Similar results were observed for CRO reads. Tumor volume CCC was 0.99 with a repeatability coefficient of 28.1%. There was excellent test-retest repeatability for FDG-PET/CT quantitative measurements across two sites and two independent reading methods. Cutoff values for determining change in SUVmean, SUVmax, and tumor volume establish limits to determine metabolic and/or volumetric response to treatment in platinum-sensitive relapsed ovarian cancer. ©2014 American Association for Cancer Research.

  20. Reconsidering Overlap-Based Measures for Quantitative Synthesis of Single-Subject Data: What They Tell Us and What They Don't

    Science.gov (United States)

    Carter, Mark

    2013-01-01

    Overlap-based measures are increasingly applied in the synthesis of single-subject research. This article considers two criticisms of overlap-based metrics, specifically that they do not measure magnitude of effect and do not adequately correspond with visual analysis. It is argued that these criticisms are based on fundamental misconceptions…

  1. No effect of 14 day consumption of whole grain diet compared to refined grain diet on antioxidant measures in healthy, young subjects: a pilot study

    Directory of Open Access Journals (Sweden)

    Slavin Joanne

    2010-03-01

    Full Text Available Abstract Background Epidemiological evidence supports that a diet high in whole grains is associated with lowered risk of chronic diseases included coronary heart disease, obesity, type 2 diabetes, and some types of cancer. One potential mechanism for the protective properties of whole grains is their antioxidant content. The aim of this study was to compare differences in antioxidant measures when subjects consumed either refined or whole grain diets. Methods Twenty healthy subjects took part in a randomized, crossover dietary intervention study. Subjects consumed either a refined grain or whole grain diet for 14 days and then the other diet for the next 14 days. Male subjects consumed 8 servings of grains per day and female subjects consumed 6 servings of grains per day. Blood and urine samples were collected at the end of each diet. Antioxidant measures included oxygen radical absorbance capacity (ORAC in blood, and isoprostanes and thiobarbituric acid reactive substances (TBARS in urine. Results The whole grain diet was significantly higher in dietary fiber, vitamin B6, folate, selenium, copper, zinc, iron, magnesium and cystine compared to the refined grain diet. Despite high intakes of whole grains, no significant differences were seen in any of the antioxidant measures between the refined and whole grain diets. Conclusions No differences in antioxidant measures were found when subjects consumed whole grain diets compared to refined grain diets.

  2. Fast kVp-switching dual energy contrast-enhanced thorax and cardiac CT: A phantom study on the accuracy of iodine concentration and effective atomic number measurement.

    Science.gov (United States)

    Papadakis, Antonios E; Damilakis, John

    2017-09-01

    To assess the effect of vessel diameter and exposure parameters on the estimation accuracy of concentration and effective atomic number (Z eff ) of iodine (I) in contrast-enhanced thorax and cardiac dual-energy CT using a modern fast kVp-switching CT scanner. A standard semi-anthropomorphic cardiac CT phantom devised to simulate the