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Sample records for enhanced spectral response

  1. Photovoltaic spectral responsivity measurements

    Energy Technology Data Exchange (ETDEWEB)

    Emery, K.; Dunlavy, D.; Field, H.; Moriarty, T. [National Renewable Energy Lab., Golden, CO (United States)

    1998-09-01

    This paper discusses the various elemental random and nonrandom error sources in typical spectral responsivity measurement systems. The authors focus specifically on the filter and grating monochrometer-based spectral responsivity measurement systems used by the Photovoltaic (PV) performance characterization team at NREL. A variety of subtle measurement errors can occur that arise from a finite photo-current response time, bandwidth of the monochromatic light, waveform of the monochromatic light, and spatial uniformity of the monochromatic and bias lights; the errors depend on the light source, PV technology, and measurement system. The quantum efficiency can be a function of he voltage bias, light bias level, and, for some structures, the spectral content of the bias light or location on the PV device. This paper compares the advantages and problems associated with semiconductor-detector-based calibrations and pyroelectric-detector-based calibrations. Different current-to-voltage conversion and ac photo-current detection strategies employed at NREL are compared and contrasted.

  2. Enhancement of nonlinear optical response of weakly confined excitons in GaAs thin films by spectrally rectangle-shape-pulse-excitation

    International Nuclear Information System (INIS)

    Kojima, O; Isu, T; Ishi-Hayase, J; Sasaki, M; Tsuchiya, M

    2007-01-01

    We report the enhancement of the nonlinear optical response of the weakly confined excitons with use of spectrally rectangular pulse. The nonlinear optical response was investigated as a function of excitation energy by a degenerate four-wave-mixing (DFWM) technique. In the case that the laser pulse with the controlled spectral shape excites the plural exciton states simultaneously, the DFWM signal intensity is enhanced by a factor of two in comparison with the intensity under the excitation of a single exciton state. This enhancement is caused by the superposition of the nonlinear optical responses from the plural exciton states

  3. Enhancing mid-infrared spectral response at the LaAlO3/SrTiO3 interface by magnetic field

    International Nuclear Information System (INIS)

    Feng, Xin; Zhao, Kun; Xi, Jian-Feng; Xiang, Wen-Feng; Lu, Zhi-Qing; Sun, Qi; Wu, Shi-Xiang; Ni, Hao

    2014-01-01

    Many unexpected properties have been found in the LaAlO 3 /SrTiO 3 heterostructure, but the interaction of the many ground states at its interface remains unclear. Here, we demonstrate an optical property of this n-type heterostructure where the mid-infrared spectral responsivity at the interface is enhanced by an external magnetic field. The field intensity ranged from 0.8 to 6 kOe at a low temperature (19 K) as measured with our spectral response measurement system. Two spectral peaks related to the spin-orbit coupling effect were also observed at wavelengths 2400 nm and 3700 nm. The intriguing phenomena relate to changes in the crystallographic structure and subband structure at the interface

  4. Contrast Enhanced Spectral Mammography: A Review.

    Science.gov (United States)

    Patel, Bhavika K; Lobbes, M B I; Lewin, John

    2018-02-01

    Contrast-enhanced spectral mammography (CESM) provides low-energy 2D mammographic images comparable to standard digital mammography and a post-contrast recombined image to assess tumor neovascularity similar to magnetic resonance imaging (MRI). The utilization of CESM in the United States is currently low but could increase rapidly given many potential indications for clinical use. This article discusses historical background and literature review of indications and diagnostic accuracy of CESM to date. CESM is a growing technique for breast cancer detection and diagnosis that has levels of sensitivity and specificity on par with contrast-enhanced breast MRI. Because of its similar performance and ease of implementation, CESM is being adopted for multiple indications previously reserved for MRI, such as problem-solving, disease extent in newly diagnosed patients, and evaluating the treatment response of neoadjuvant chemotherapy. Copyright © 2018 Elsevier Inc. All rights reserved.

  5. Nanoscale resonant-cavity-enhanced germanium photodetectors with lithographically defined spectral response for improved performance at telecommunications wavelengths.

    Science.gov (United States)

    Balram, Krishna C; Audet, Ross M; Miller, David A B

    2013-04-22

    We demonstrate the use of a subwavelength planar metal-dielectric resonant cavity to enhance the absorption of germanium photodetectors at wavelengths beyond the material's direct absorption edge, enabling high responsivity across the entire telecommunications C and L bands. The resonant wavelength of the detectors can be tuned linearly by varying the width of the Ge fin, allowing multiple detectors, each resonant at a different wavelength, to be fabricated in a single-step process. This approach is promising for the development of CMOS-compatible devices suitable for integrated, high-speed, and energy-efficient photodetection at telecommunications wavelengths.

  6. Planck 2013 results. IX. HFI spectral response

    CERN Document Server

    Ade, P A R; Armitage-Caplan, C; Arnaud, M; Ashdown, M; Atrio-Barandela, F; Aumont, J; Baccigalupi, C; Banday, A J; Barreiro, R B; Battaner, E; Benabed, K; Benoît, A; Benoit-Lévy, A; Bernard, J -P; Bersanelli, M; Bielewicz, P; Bobin, J; Bock, J J; Bond, J R; Borrill, J; Bouchet, F R; Boulanger, F; Bridges, M; Bucher, M; Burigana, C; Cardoso, J -F; Catalano, A; Challinor, A; Chamballu, A; Chary, R -R; Chen, X; Chiang, L -Y; Chiang, H C; Christensen, P R; Church, S; Clements, D L; Colombi, S; Colombo, L P L; Combet, C; Comis, B; Couchot, F; Coulais, A; Crill, B P; Curto, A; Cuttaia, F; Danese, L; Davies, R D; de Bernardis, P; de Rosa, A; de Zotti, G; Delabrouille, J; Delouis, J -M; Désert, F -X; Dickinson, C; Diego, J M; Dole, H; Donzelli, S; Doré, O; Douspis, M; Dupac, X; Efstathiou, G; Enßlin, T A; Eriksen, H K; Falgarone, E; Finelli, F; Forni, O; Frailis, M; Franceschi, E; Galeotta, S; Ganga, K; Giard, M; Giraud-Héraud, Y; González-Nuevo, J; Górski, K M; Gratton, S; Gregorio, A; Gruppuso, A; Hansen, F K; Hanson, D; Harrison, D; Henrot-Versillé, S; Hernández-Monteagudo, C; Herranz, D; Hildebrandt, S R; Hivon, E; Hobson, M; Holmes, W A; Hornstrup, A; Hovest, W; Huffenberger, K M; Hurier, G; Jaffe, T R; Jaffe, A H; Jones, W C; Juvela, M; Keihänen, E; Keskitalo, R; Kisner, T S; Kneissl, R; Knoche, J; Knox, L; Kunz, M; Kurki-Suonio, H; Lagache, G; Lamarre, J -M; Lasenby, A; Laureijs, R J; Lawrence, C R; Leahy, J P; Leonardi, R; Leroy, C; Lesgourgues, J; Liguori, M; Lilje, P B; Linden-Vørnle, M; López-Caniego, M; Lubin, P M; Macías-Pérez, J F; Maffei, B; Mandolesi, N; Maris, M; Marshall, D J; Martin, P G; Martínez-González, E; Masi, S; Matarrese, S; Matthai, F; Mazzotta, P; McGehee, P; Melchiorri, A; Mendes, L; Mennella, A; Migliaccio, M; Mitra, S; Miville-Deschênes, M -A; Moneti, A; Montier, L; Morgante, G; Mortlock, D; Munshi, D; Murphy, J A; Naselsky, P; Nati, F; Natoli, P; Netterfield, C B; Nørgaard-Nielsen, H U; North, C; Noviello, F; Novikov, D; Novikov, I; Osborne, S; Oxborrow, C A; Paci, F; Pagano, L; Pajot, F; Paoletti, D; Pasian, F; Patanchon, G; Perdereau, O; Perotto, L; Perrotta, F; Piacentini, F; Piat, M; Pierpaoli, E; Pietrobon, D; Plaszczynski, S; Pointecouteau, E; Polenta, G; Ponthieu, N; Popa, L; Poutanen, T; Pratt, G W; Prézeau, G; Prunet, S; Puget, J -L; Rachen, J P; Reinecke, M; Remazeilles, M; Renault, C; Ricciardi, S; Riller, T; Ristorcelli, I; Rocha, G; Rosset, C; Roudier, G; Rusholme, B; Santos, D; Savini, G; Shellard, E P S; Spencer, L D; Starck, J -L; Stolyarov, V; Stompor, R; Sudiwala, R; Sureau, F; Sutton, D; Suur-Uski, A -S; Sygnet, J -F; Tauber, J A; Tavagnacco, D; Terenzi, L; Tomasi, M; Tristram, M; Tucci, M; Umana, G; Valenziano, L; Valiviita, J; Van Tent, B; Vielva, P; Villa, F; Vittorio, N; Wade, L A; Wandelt, B D; Yvon, D; Zacchei, A; Zonca, A

    2014-01-01

    The Planck High Frequency Instrument (HFI) spectral response was determined through a series of ground based tests conducted with the HFI focal plane in a cryogenic environment prior to launch. The main goal of the spectral transmission tests was to measure the relative spectral response (including out-of-band signal rejection) of all HFI detectors. This was determined by measuring the output of a continuously scanned Fourier transform spectrometer coupled with all HFI detectors. As there is no on-board spectrometer within HFI, the ground-based spectral response experiments provide the definitive data set for the relative spectral calibration of the HFI. The spectral response of the HFI is used in Planck data analysis and component separation, this includes extraction of CO emission observed within Planck bands, dust emission, Sunyaev-Zeldovich sources, and intensity to polarization leakage. The HFI spectral response data have also been used to provide unit conversion and colour correction analysis tools. Ver...

  7. Spectral Purity Enhancement via Polyphase Multipath Circuits

    NARCIS (Netherlands)

    Mensink, E.; Klumperink, Eric A.M.; Nauta, Bram

    2004-01-01

    The central question of this paper is: can we enhance the spectral purity of nonlinear circuits by using polyphase multipath circuits? The basic idea behind polyphase multipath circuits is to split the nonlinear circuits into two or more paths and exploit phase differences between these paths to

  8. COFFEE - Coherent Optical System Field Trial for Spectral Efficiency Enhancement

    DEFF Research Database (Denmark)

    Imran, Muhammad; Fresi, Francesco; Rommel, Simon

    2016-01-01

    The scope, aims, and contributions of the COFFEE project for spectral efficiency enhancement and market exposure are presented.......The scope, aims, and contributions of the COFFEE project for spectral efficiency enhancement and market exposure are presented....

  9. Spacetime Discontinuous Galerkin FEM: Spectral Response

    International Nuclear Information System (INIS)

    Abedi, R; Omidi, O; Clarke, P L

    2014-01-01

    Materials in nature demonstrate certain spectral shapes in terms of their material properties. Since successful experimental demonstrations in 2000, metamaterials have provided a means to engineer materials with desired spectral shapes for their material properties. Computational tools are employed in two different aspects for metamaterial modeling: 1. Mircoscale unit cell analysis to derive and possibly optimize material's spectral response; 2. macroscale to analyze their interaction with conventional material. We compare two different approaches of Time-Domain (TD) and Frequency Domain (FD) methods for metamaterial applications. Finally, we discuss advantages of the TD method of Spacetime Discontinuous Galerkin finite element method (FEM) for spectral analysis of metamaterials

  10. Spectral entropy and haemodynamic response to surgery during ...

    African Journals Online (AJOL)

    Adele

    Spectral entropy and haemodynamic response to surgery during sevoflurane anaesthesia. Introduction. Apart from somatic responses, surgery also evokes autonomic responses, including haemodynamic responses. Spectral entropy has been validated as a means to monitor the hypnotic state during sevoflurane ...

  11. Contrast-enhanced Spectral Mammography: Technique, Indications, and Clinical Applications.

    Science.gov (United States)

    Bhimani, Chandni; Matta, Danielle; Roth, Robyn G; Liao, Lydia; Tinney, Elizabeth; Brill, Kristin; Germaine, Pauline

    2017-01-01

    Contrast-enhanced spectral mammography (CESM) combines the benefits of full field digital mammography with the concept of tumor angiogenesis. Technique and practical applications of CESM are discussed. An overview of the technique is followed by a demonstration of practical applications of CESM in our practice. We have successfully implemented CESM into our practice as a screening, diagnostic, staging, and treatment response tool. It is important to understand the technique of CESM and how to incorporate it into practice. Copyright © 2017 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved.

  12. Spectral response analysis of PVDF capacitive sensors

    Science.gov (United States)

    Reyes-Ramírez, B.; García-Segundo, C.; García-Valenzuela, A.

    2013-06-01

    We investigate the spectral response to ultrasound waves in water of low-noise capacitive sensors based on PVDF polymer piezoelectric films. First, we analyze theoretically the mechanical-to-electrical transduction as a function of the frequency of ultrasonic signals and derive an analytic expression of the sensor's transfer function. Then we present experimental results of the frequency response of a home-made PDVF in water to test signals from 1 to 20 MHz induced by a commercial hydrophone powered by a signal generator and compare with our theoretical model.

  13. Digital staining for histopathology multispectral images by the combined application of spectral enhancement and spectral transformation.

    Science.gov (United States)

    Bautista, Pinky A; Yagi, Yukako

    2011-01-01

    In this paper we introduced a digital staining method for histopathology images captured with an n-band multispectral camera. The method consisted of two major processes: enhancement of the original spectral transmittance and the transformation of the enhanced transmittance to its target spectral configuration. Enhancement is accomplished by shifting the original transmittance with the scaled difference between the original transmittance and the transmittance estimated with m dominant principal component (PC) vectors;the m-PC vectors were determined from the transmittance samples of the background image. Transformation of the enhanced transmittance to the target spectral configuration was done using an nxn transformation matrix, which was derived by applying a least square method to the enhanced and target spectral training data samples of the different tissue components. Experimental results on the digital conversion of a hematoxylin and eosin (H&E) stained multispectral image to its Masson's trichrome stained (MT) equivalent shows the viability of the method.

  14. Planck 2013 results. IX. HFI spectral response

    DEFF Research Database (Denmark)

    Planck Collaboration,; Ade, P. A. R.; Aghanim, N.

    2013-01-01

    -of-band signal rejection) of all HFI detectors to a known source of electromagnetic radiation individually. This was determined by measuring the output of all detection channels for radiation propagated through a continuously scanned polarizing Fourier transform spectrometer. As there is no on-board spectrometer......, dust emission, Sunyaev Zeldovich sources, and intensity to polarization leakage. The HFI spectral response data have also been used to provide unit conversion and colour correction analysis tools. While previous papers have already described the pre-flight experiments conducted on the Planck HFI...

  15. Slow-Light-Enhanced Spectral Interferometers, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — We proposoe a research program aimed at developing spectral interferometers with dramatically enhanced performance. A key aspect of our approach is to place a highly...

  16. CONTRAST ENHANCED SPECTRAL MAMMOGRAPHY (CESM (REVIEW

    Directory of Open Access Journals (Sweden)

    N. I. Rozhkova

    2015-01-01

    Full Text Available The problem of early diagnosis of a breast cancer is extremely actual. Growth of incidence at women from 19 to 39 years increased for 34% over the last 10 years. It defines need of acceleration of development and deployment of the latest technologies of identification of the earliest symptoms of diseases. The x-ray mammography is the conducting method among of all radiological methods of diagnostics. Nevertheless a number of restrictions of method reduces its efficiency. The technologies increasing informational content of x-ray mammography – the leading method of screening – due to use of artificial contrasting and advantages of digital technologies are constantly developed. In this review it is described works, in which the authors having clinical experience of application of CESM – contrastenhanced spectral mammography on representative group of women. Positive sides and restrictions of new technology in comparison with mammography, ultrasonography and MRT are shown in this article.

  17. Effect of Surface Plasmon Coupling to Optical Cavity Modes on the Field Enhancement and Spectral Response of Dimer-Based sensors

    KAUST Repository

    Alrasheed, Salma

    2017-09-05

    We present a theoretical approach to narrow the plasmon linewidth and enhance the near-field intensity at a plasmonic dimer gap (hot spot) through coupling the electric localized surface plasmon (LSP) resonance of a silver hemispherical dimer with the resonant modes of a Fabry-Perot (FP) cavity. The strong coupling is demonstrated by the large anticrossing in the reflection spectra and a Rabi splitting of 76 meV. Up to 2-fold enhancement increase can be achieved compared to that without using the cavity. Such high field enhancement has potential applications in optics, including sensors and high resolution imaging devices. In addition, the resonance splitting allows for greater flexibility in using the same array at different wavelengths. We then further propose a practical design to realize such a device and include dimers of different shapes and materials.

  18. Effect of Surface Plasmon Coupling to Optical Cavity Modes on the Field Enhancement and Spectral Response of Dimer-Based sensors

    KAUST Repository

    Alrasheed, Salma; Di Fabrizio, Enzo M.

    2017-01-01

    with the resonant modes of a Fabry-Perot (FP) cavity. The strong coupling is demonstrated by the large anticrossing in the reflection spectra and a Rabi splitting of 76 meV. Up to 2-fold enhancement increase can be achieved compared to that without using the cavity

  19. Relative spectral response calibration using Ti plasma lines

    Science.gov (United States)

    Teng, FEI; Congyuan, PAN; Qiang, ZENG; Qiuping, WANG; Xuewei, DU

    2018-04-01

    This work introduces the branching ratio (BR) method for determining relative spectral responses, which are needed routinely in laser induced breakdown spectroscopy (LIBS). Neutral and singly ionized Ti lines in the 250–498 nm spectral range are investigated by measuring laser-induced micro plasma near a Ti plate and used to calculate the relative spectral response of an entire LIBS detection system. The results are compared with those of the conventional relative spectral response calibration method using a tungsten halogen lamp, and certain lines available for the BR method are selected. The study supports the common manner of using BRs to calibrate the detection system in LIBS setups.

  20. Spectral efficiency enhancement with interference cancellation for wireless relay network

    DEFF Research Database (Denmark)

    Yomo, Hiroyuki; De Carvalho, Elisabeth

    The introduction of relaying into wireless communication system for coverage enhancement can cause severe decrease of spectral efficiency due to the requirement on extra radio resource. In this paper, we propose a method to increase spectral efficiency in such a wireless relay network by employing...... an interference cancellation technique. We focus on a typical scenario of relaying in a cellular system, where a mobile station (MS) requires the help of a relay station (RS) to communicate with the base station (BS). In such a case, interference cancellation can be used to achieve a small reuse distance...... of identical radio resource. We analyze a simple scenario with BS, single RS, and 2 MSs, and show that the proposed method has significant potential to enhance spectral efficiency in wireless relay networks....

  1. Dual-energy contrast-enhanced spectral mammography (CESM).

    Science.gov (United States)

    Daniaux, Martin; De Zordo, Tobias; Santner, Wolfram; Amort, Birgit; Koppelstätter, Florian; Jaschke, Werner; Dromain, Clarisse; Oberaigner, Willi; Hubalek, Michael; Marth, Christian

    2015-10-01

    Dual-energy contrast-enhanced mammography is one of the latest developments in breast care. Imaging with contrast agents in breast cancer was already known from previous magnetic resonance imaging and computed tomography studies. However, high costs, limited availability-or high radiation dose-led to the development of contrast-enhanced spectral mammography (CESM). We reviewed the current literature, present our experience, discuss the advantages and drawbacks of CESM and look at the future of this innovative technique.

  2. Contrast-enhanced spectral mammography in patients with MRI contraindications.

    Science.gov (United States)

    Richter, Vivien; Hatterman, Valerie; Preibsch, Heike; Bahrs, Sonja D; Hahn, Markus; Nikolaou, Konstantin; Wiesinger, Benjamin

    2017-01-01

    Background Contrast-enhanced spectral mammography (CESM) is a novel breast imaging technique providing comparable diagnostic accuracy to breast magnetic resonance imaging (MRI). Purpose To show that CESM in patients with MRI contraindications is feasible, accurate, and useful as a problem-solving tool, and to highlight its limitations. Material and Methods A total of 118 patients with MRI contraindications were examined by CESM. Histology was obtained in 94 lesions and used as gold standard for diagnostic accuracy calculations. Imaging data were reviewed retrospectively for feasibility, accuracy, and technical problems. The diagnostic yield of CESM as a problem-solving tool and for therapy response evaluation was reviewed separately. Results CESM was more accurate than mammography (MG) for lesion categorization (r = 0.731, P < 0.0001 vs. r = 0.279, P = 0.006) and for lesion size estimation (r = 0.738 vs. r = 0.689, P < 0.0001). Negative predictive value of CESM was significantly higher than of MG (85.71% vs. 30.77%, P < 0.0001). When used for problem-solving, CESM changed patient management in 2/8 (25%) cases. Superposition artifacts and timing problems affected diagnostic utility in 3/118 (2.5%) patients. Conclusion CESM is a feasible and accurate alternative for patients with MRI contraindications, but it is necessary to be aware of the method's technical limitations.

  3. Comparison of Background Parenchymal Enhancement at Contrast-enhanced Spectral Mammography and Breast MR Imaging.

    Science.gov (United States)

    Sogani, Julie; Morris, Elizabeth A; Kaplan, Jennifer B; D'Alessio, Donna; Goldman, Debra; Moskowitz, Chaya S; Jochelson, Maxine S

    2017-01-01

    Purpose To assess the extent of background parenchymal enhancement (BPE) at contrast material-enhanced (CE) spectral mammography and breast magnetic resonance (MR) imaging, to evaluate interreader agreement in BPE assessment, and to examine the relationships between clinical factors and BPE. Materials and Methods This was a retrospective, institutional review board-approved, HIPAA-compliant study. Two hundred seventy-eight women from 25 to 76 years of age with increased breast cancer risk who underwent CE spectral mammography and MR imaging for screening or staging from 2010 through 2014 were included. Three readers independently rated BPE on CE spectral mammographic and MR images with the ordinal scale: minimal, mild, moderate, or marked. To assess pairwise agreement between BPE levels on CE spectral mammographic and MR images and among readers, weighted κ coefficients with quadratic weights were calculated. For overall agreement, mean κ values and bootstrapped 95% confidence intervals were calculated. The univariate and multivariate associations between BPE and clinical factors were examined by using generalized estimating equations separately for CE spectral mammography and MR imaging. Results Most women had minimal or mild BPE at both CE spectral mammography (68%-76%) and MR imaging (69%-76%). Between CE spectral mammography and MR imaging, the intrareader agreement ranged from moderate to substantial (κ = 0.55-0.67). Overall agreement on BPE levels between CE spectral mammography and MR imaging and among readers was substantial (κ = 0.66; 95% confidence interval: 0.61, 0.70). With both modalities, BPE demonstrated significant association with menopausal status, prior breast radiation therapy, hormonal treatment, breast density on CE spectral mammographic images, and amount of fibroglandular tissue on MR images (P spectral mammographic and MR images. © RSNA, 2016.

  4. Detector response artefacts in spectral reconstruction

    DEFF Research Database (Denmark)

    Olsen, Ulrik Lund; Christensen, Erik D.; Khalil, Mohamad

    2017-01-01

    Energy resolved detectors are gaining traction as a tool to achieve better material contrast. K-edge imaging and tomography is an example of a method with high potential that has evolved on the capabilities of photon counting energy dispersive detectors. Border security is also beginning to see...... instruments taking advantage of energy resolved detectors. The progress of the field is halted by the limitations of the detectors. The limitations include nonlinear response for both x-ray intensity and x-ray spectrum. In this work we investigate how the physical interactions in the energy dispersive...

  5. Spectral response of a polycrystalline silicon solar cell

    International Nuclear Information System (INIS)

    Ba, B.; Kane, M.

    1994-10-01

    A theoretical study of the spectral response of a polycrystalline silicon n-p junction solar cell is presented. The case of a fibrously oriented grain structure, involving grain boundary recombination velocity and grain size effects is discussed. The contribution of the base region on the internal quantum efficiency Q int is computed for different grain sizes and grain boundary recombination velocities in order to examine their influence. Suggestions are also made for the determination of base diffusion length in polycrystalline silicon solar cells using the spectral response method. (author). 15 refs, 4 figs

  6. Challenges in contrast-enhanced spectral mammography interpretation: artefacts lexicon.

    Science.gov (United States)

    Yagil, Y; Shalmon, A; Rundstein, A; Servadio, Y; Halshtok, O; Gotlieb, M; Sklair-Levy, M

    2016-05-01

    To review and describe commonly encountered artefacts in contrast-enhanced spectral mammography (CESM). This retrospective study included 200 women who underwent CESM examinations for screening and diagnostic purposes. Analysis was performed on the image data sets of these women, comprising of a total of 774 subtracted images. Images were reviewed with focus on the presence of four artefacts: rim ("breast within breast"), ripple (black and white lines), axillary line, and skin-line enhancement (skin-line highlighting). Statistical cross-correlation and association with acquisition parameters (tube current, tube voltage, compression force, breast thickness, paddle size) was compared using Fisher's exact test and t-test. The rim artefact was highly common (97-99%) in every projection. The ripple artefact was increasingly more common on the oblique projections (80-82%) and found to be associated with higher breast thickness values. The axillary line artefact was detected only on oblique projections (63%) and associated with the use of a small compression paddle. The skin-line enhancement artefact was seen in 19-46% of projections. None of the artefacts interfered with image interpretation. Two main artefacts commonly seen on CESM are rim and ripple artefacts. They do not hamper with image interpretation. It is important to be aware of them and prevent misinterpretation of these artefacts as real breast pathology. Copyright © 2016 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

  7. SPECTRAL AMPLITUDE CODING OCDMA SYSTEMS USING ENHANCED DOUBLE WEIGHT CODE

    Directory of Open Access Journals (Sweden)

    F.N. HASOON

    2006-12-01

    Full Text Available A new code structure for spectral amplitude coding optical code division multiple access systems based on double weight (DW code families is proposed. The DW has a fixed weight of two. Enhanced double-weight (EDW code is another variation of a DW code family that can has a variable weight greater than one. The EDW code possesses ideal cross-correlation properties and exists for every natural number n. A much better performance can be provided by using the EDW code compared to the existing code such as Hadamard and Modified Frequency-Hopping (MFH codes. It has been observed that theoretical analysis and simulation for EDW is much better performance compared to Hadamard and Modified Frequency-Hopping (MFH codes.

  8. Accurate and independent spectral response scale based on silicon trap detectors and spectrally invariant detectors

    International Nuclear Information System (INIS)

    Gran, Jarle

    2005-01-01

    The study aims to establish an independent high accuracy spectral response scale over a broad spectral range based on standard laboratory equipment at a moderate cost. This had to be done by a primary method, where the responsivity of the detector is linked to fundamental constants. Summary, conclusion and future directions: In this thesis it has been demonstrated that an independent spectral response scale from the visual to the IR based on simple relative measurements can be established. The accuracy obtained by the hybrid self-calibration method demonstrates that state of the art accuracy is obtained with self-calibration principles. A calculable silicon trap detector with low internal losses over a wide spectral range is needed to establish the scale, in addition to a linear, spectrally independent detector with a good signal to noise ratio. By fitting the parameters in the responsivity model to a purely relative measurement we express the spectral response in terms of fundamental constants with a known uncertainty This is therefore a primary method. By applying a digital filter on the relative measurements of the InGaAs detectors in the infrared reduces the standard deviation by 30 %. In addition, by optimising the necessary scaling constant converting the relative calibration to absolute values, we have managed to establish an accurate and cost efficient spectral response scale in the IR. The full covariance analysis, which takes into account the correlation in the absolute values of the silicon detector, the correlation caused by the filter and the scaling constant, shows that the spectral response scale established in the infrared with InGaAs detectors is done with high accuracy. A similar procedure can be used in the UV, though it has not been demonstrated here. In fig. 10 the responsitivities of the detectors (a) and their associated uncertainties (b) at the 1 sigma level of confidence is compared for the three publications. We see that the responsivity

  9. Measured Polarized Spectral Responsivity of JPSS J1 VIIRS Using the NIST T-SIRCUS

    Science.gov (United States)

    McIntire, Jeff; Young, James B.; Moyer, David; Waluschka, Eugene; Xiong, Xiaoxiong

    2015-01-01

    Recent pre-launch measurements performed on the Joint Polar Satellite System (JPSS) J1 Visible Infrared Imaging Radiometer Suite (VIIRS) using the National Institute of Standards and Technology (NIST) Traveling Spectral Irradiance and Radiance Responsivity Calibrations Using Uniform Sources (T-SIRCUS) monochromatic source have provided wavelength dependent polarization sensitivity for select spectral bands and viewing conditions. Measurements were made at a number of input linear polarization states (twelve in total) and initially at thirteen wavelengths across the bandpass (later expanded to seventeen for some cases). Using the source radiance information collected by an external monitor, a spectral responsivity function was constructed for each input linear polarization state. Additionally, an unpolarized spectral responsivity function was derived from these polarized measurements. An investigation of how the centroid, bandwidth, and detector responsivity vary with polarization state was weighted by two model input spectra to simulate both ground measurements as well as expected on-orbit conditions. These measurements will enhance our understanding of VIIRS polarization sensitivity, improve the design for future flight models, and provide valuable data to enhance product quality in the post-launch phase.

  10. Investigation of JI and DI CMOS FXR response at different spectral energies

    International Nuclear Information System (INIS)

    Honnold, V.R.; Goldberg, M.; Schreiner, W.A.; Witteles, A.A.

    1975-01-01

    The transient response of both junction isolated (JI) and dielectrically isolated (DI) CMOS circuits has been investigated in three FXR environments of differing energy spectrums. The offset recovery times have been measured and analyzed for both structures. It is shown that while the DI circuit (HD4007) did not exhibit a four layer type latchup action, its transient response persisted for a time longer than is expected for this type of device. A possible mechanism for this observed response is developed and discussed. JI circuits (CD4007) exposed under the same conditions exhibited four layer device action and one sample at low spectral energies latched-up. The conditions for the latchup to occur including the four layer device paths are discussed. Finally, the dependence of the x-ray transient response on the spectral energy is considered. For the lower energy FXR source, latchup was observed in a CD4007 sample. This latchup was not observed at more than double the dose rate when a high energy FXR was used. This result is attributed to dose enhancement, and a device enhancement factor may also be involved. The dose enhancement factor is estimated from the work of Long, and points up the importance of accounting for the spectral energy content in simulating a given nuclear threat spectrum

  11. Comparison between breast MRI and contrast-enhanced spectral mammography.

    Science.gov (United States)

    Łuczyńska, Elżbieta; Heinze-Paluchowska, Sylwia; Hendrick, Edward; Dyczek, Sonia; Ryś, Janusz; Herman, Krzysztof; Blecharz, Paweł; Jakubowicz, Jerzy

    2015-05-12

    The main goal of this study was to compare contrast-enhanced spectral mammography (CESM) and breast magnetic resonance imaging (MRI) with histopathological results and to compare the sensitivity, accuracy, and positive and negative predictive values for both imaging modalities. After ethics approval, CESM and MRI examinations were performed in 102 patients who had suspicious lesions described in conventional mammography. All visible lesions were evaluated independently by 2 experienced radiologists using BI-RADS classifications (scale 1-5). Dimensions of lesions measured with each modality were compared to postoperative histopathology results. There were 102 patients entered into CESM/MRI studies and 118 lesions were identified by the combination of CESM and breast MRI. Histopathology confirmed that 81 of 118 lesions were malignant and 37 were benign. Of the 81 malignant lesions, 72 were invasive cancers and 9 were in situ cancers. Sensitivity was 100% with CESM and 93% with breast MRI. Accuracy was 79% with CESM and 73% with breast MRI. ROC curve areas based on BI-RADS were 0.83 for CESM and 0.84 for breast MRI. Lesion size estimates on CESM and breast MRI were similar, both slightly larger than those from histopathology. Our results indicate that CESM has the potential to be a valuable diagnostic method that enables accurate detection of malignant breast lesions, has high negative predictive value, and a false-positive rate similar to that of breast MRI.

  12. Spectral response of THM grown CdZnTe crystals

    DEFF Research Database (Denmark)

    Chen, H.; Awadalla, S.A.; Harris, F.

    2008-01-01

    The spectral response of several crystals grown by the Traveling Heater Method (THM) were investigated. An energy resolution of 0.98% for a Pseudo Frisch-Grid of 4 × 4 × 9 mm3 and 2.1% FWHM for a coplanar-grid of size 11 × 11 × 5 mm3 were measured using 137Cs-662 keV. In addition a 4% FWHM at 122...

  13. Quantitative analysis of enhanced malignant and benign lesions on contrast-enhanced spectral mammography.

    Science.gov (United States)

    Deng, Chih-Ying; Juan, Yu-Hsiang; Cheung, Yun-Chung; Lin, Yu-Ching; Lo, Yung-Feng; Lin, GiGin; Chen, Shin-Cheh; Ng, Shu-Hang

    2018-02-27

    To retrospectively analyze the quantitative measurement and kinetic enhancement among pathologically proven benign and malignant lesions using contrast-enhanced spectral mammography (CESM). We investigated the differences in enhancement between 44 benign and 108 malignant breast lesions in CESM, quantifying the extent of enhancements and the relative enhancements between early (between 2-3 min after contrast medium injection) and late (3-6 min) phases. The enhancement was statistically stronger in malignancies compared to benign lesions, with good performance by the receiver operating characteristic curve [0.877, 95% confidence interval (0.813-0.941)]. Using optimal cut-off value at 220.94 according to Youden index, the sensitivity was 75.9%, specificity 88.6%, positive likelihood ratio 6.681, negative likelihood ratio 0.272 and accuracy 82.3%. The relative enhancement patterns of benign and malignant lesions, showing 29.92 vs 73.08% in the elevated pattern, 7.14 vs 92.86% in the steady pattern, 5.71 vs 94.29% in the depressed pattern, and 80.00 vs 20.00% in non-enhanced lesions (p < 0.0001), respectively. Despite variations in the degree of tumour angiogenesis, quantitative analysis of the breast lesions on CESM documented the malignancies had distinctive stronger enhancement and depressed relative enhancement patterns than benign lesions. Advances in knowledge: To our knowledge, this is the first study evaluating the feasibility of quantifying lesion enhancement on CESM. The quantities of enhancement were informative for assessing breast lesions in which the malignancies had stronger enhancement and more relative depressed enhancement than the benign lesions.

  14. Methods for Enhancing Geological Structures in Spectral Spatial Difference-Based on Remote-Sensing Image

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    @@In this paper, some image processing methods such as directional template (mask) matching enhancement, pseudocolor or false color enhancement, K-L transform enhancement are used to enhance a geological structure, one of important ore-controlling factors, shown in the remote-sensing images.This geological structure is regarded as image anomaly in the remote-sensing image, since considerable differences, based on the spatial spectral distribution pattern, in gray values (spectral), color tones and texture, are always present between the geological structure and background. Therefore,the enhancement of the geological structure in the remotesensing image is that of the spectral spatial difference.

  15. Prediction of spectral acceleration response ordinates based on PGA attenuation

    Science.gov (United States)

    Graizer, V.; Kalkan, E.

    2009-01-01

    Developed herein is a new peak ground acceleration (PGA)-based predictive model for 5% damped pseudospectral acceleration (SA) ordinates of free-field horizontal component of ground motion from shallow-crustal earthquakes. The predictive model of ground motion spectral shape (i.e., normalized spectrum) is generated as a continuous function of few parameters. The proposed model eliminates the classical exhausted matrix of estimator coefficients, and provides significant ease in its implementation. It is structured on the Next Generation Attenuation (NGA) database with a number of additions from recent Californian events including 2003 San Simeon and 2004 Parkfield earthquakes. A unique feature of the model is its new functional form explicitly integrating PGA as a scaling factor. The spectral shape model is parameterized within an approximation function using moment magnitude, closest distance to the fault (fault distance) and VS30 (average shear-wave velocity in the upper 30 m) as independent variables. Mean values of its estimator coefficients were computed by fitting an approximation function to spectral shape of each record using robust nonlinear optimization. Proposed spectral shape model is independent of the PGA attenuation, allowing utilization of various PGA attenuation relations to estimate the response spectrum of earthquake recordings.

  16. Spectral responsivity-based calibration of photometer and colorimeter standards

    Science.gov (United States)

    Eppeldauer, George P.

    2013-08-01

    Several new generation transfer- and working-standard illuminance meters and tristimulus colorimeters have been developed at the National Institute of Standards and Technology (NIST) [1] to measure all kinds of light sources with low uncertainty. The spectral and broad-band (illuminance) responsivities of the photometer (Y) channels of two tristimulus meters were determined at both the Spectral Irradiance and Radiance Responsivity Calibrations using Uniform Sources (SIRCUS) facility and the Spectral Comparator Facility (SCF) [2]. The two illuminance responsivities agreed within 0.1% with an overall uncertainty of 0.2% (k = 2), which is a factor of two improvement over the present NIST photometric scale. The first detector-based tristimulus color scale [3] was realized. All channels of the reference tristimulus colorimeter were calibrated at the SIRCUS. The other tristimulus meters were calibrated at the SCF and also against the reference meter on the photometry bench in broad-band measurement mode. The agreement between detector- and source-based calibrations was within 3 K when a tungsten lamp-standard was measured at 2856 K and 3100 K [4]. The color-temperature uncertainty of tungsten lamp measurements was 4 K (k = 2) between 2300 K and 3200 K, which is a factor of two improvement over the presently used NIST source-based color temperature scale. One colorimeter was extended with an additional (fifth) channel to apply software implemented matrix corrections. With this correction, the spectral mismatch caused color difference errors were decreased by a factor of 20 for single-color LEDs.

  17. Assessing Cd-induced stress from plant spectral response

    Science.gov (United States)

    Kancheva, Rumiana; Georgiev, Georgi

    2014-10-01

    Remote sensing plays a significant role in local, regional and global monitoring of land covers. Ecological concerns worldwide determine the importance of remote sensing applications for the assessment of soil conditions, vegetation health and identification of stress-induced changes. The extensive industrial growth and intensive agricultural land-use arise the serious ecological problem of environmental pollution associated with the increasing anthropogenic pressure on the environment. Soil contamination is a reason for degradation processes and temporary or permanent decrease of the productive capacity of land. Heavy metals are among the most dangerous pollutants because of their toxicity, persistent nature, easy up-take by plants and long biological half-life. This paper takes as its focus the study of crop species spectral response to Cd pollution. Ground-based experiments were performed, using alfalfa, spring barley and pea grown in Cd contaminated soils and in different hydroponic systems under varying concentrations of the heavy metal. Cd toxicity manifested itself by inhibition of plant growth and synthesis of photosynthetic pigments. Multispectral reflectance, absorbance and transmittance, as well as red and far red fluorescence were measured and examined for their suitability to detect differences in plant condition. Statistical analysis was performed and empirical relationships were established between Cd concentration, plant growth variables and spectral response Various spectral properties proved to be indicators of plant performance and quantitative estimators of the degree of the Cd-induced stress.

  18. Spectral responses of gravel beaches to tidal signals

    Science.gov (United States)

    Geng, Xiaolong; Boufadel, Michel C.

    2017-01-01

    Tides have been recognized as a major driving forcing affecting coastal aquifer system, and deterministic modeling has been very effective in elucidating mechanisms caused by tides. However, such modeling does not lend itself to capture embedded information in the signal, and rather focuses on the primary processes. Here, using yearlong data sets measured at beaches in Alaska Prince William Sound, we performed spectral and correlation analyses to identify temporal behavior of pore-water pressure, temperature and salinity. We found that the response of the beach system was characterized by fluctuations of embedded diurnal, semidiurnal, terdiurnal and quarterdiurnal tidal components. Hydrodynamic dispersion of salinity and temperature, and the thermal conductivity greatly affected pore water signals. Spectral analyses revealed a faster dissipation of the semi-diurnal component with respect to the diurnal components. Correlation functions showed that salinity had a relatively short memory of the tidal signal when inland freshwater recharge was large. In contrast, the signature of the tidal signal on pore-water temperature persisted for longer times, up to a week. We also found that heterogeneity greatly affected beach response. The response varied from a simple linear mapping in the frequency domain to complete modulation and masking of the input frequencies.

  19. Spectral response data for development of cool coloured tile coverings

    Science.gov (United States)

    Libbra, Antonio; Tarozzi, Luca; Muscio, Alberto; Corticelli, Mauro A.

    2011-03-01

    Most ancient or traditional buildings in Italy show steep-slope roofs covered by red clay tiles. As the rooms immediately below the roof are often inhabited in historical or densely urbanized centres, the combination of low solar reflectance of tile coverings and low thermal inertia of either wooden roof structures or sub-tile insulation panels makes summer overheating a major problem. The problem can be mitigated by using tiles coated with cool colours, that is colours with the same spectral response of clay tiles in the visible, but highly reflecting in the near infrared range, which includes more than half of solar radiation. Cool colours can yield the same visible aspect of common building surfaces, but higher solar reflectance. Studies aimed at developing cool colour tile coverings for traditional Italian buildings have been started. A few coating solutions with the typical red terracotta colour have been produced and tested in the laboratory, using easily available materials. The spectral response and the solar reflectance have been measured and compared with that of standard tiles.

  20. Impact of spectral nudging and domain size in studies of RCM response to parameter modification

    Energy Technology Data Exchange (ETDEWEB)

    Separovic, Leo; Laprise, Rene [Universite du Quebec a Montreal, Centre pour l' Etude et la Simulation du Climat a l' Echelle Regionale (ESCER), Montreal, QC (Canada); Universite du Quebec a Montreal (UQAM), Montreal, QC (Canada); Elia, Ramon de [Universite du Quebec a Montreal, Centre pour l' Etude et la Simulation du Climat a l' Echelle Regionale (ESCER), Montreal, QC (Canada); Consortium Ouranos, Montreal, QC (Canada)

    2012-04-15

    The paper aims at finding an RCM configuration that facilitates studies devoted to quantifying RCM response to parameter modification. When using short integration times, the response of the time-averaged variables to RCM modification tend to be blurred by the noise originating in the lack of predictability of the instantaneous atmospheric states. Two ways of enhancing the signal-to-noise ratio are studied in this work: spectral nudging and reduction of the computational domain size. The approach followed consists in the analysis of the sensitivity of RCM-simulated seasonal averages to perturbations of two parameters controlling deep convection and stratiform condensation, perturbed one at a time. Sensitivity is analyzed within different simulation configurations obtained by varying domain size and using the spectral nudging option. For each combination of these factors multiple members of identical simulations that differ exclusively in initial conditions are also generated to provide robust estimates of the sensitivities (the signal) and sample the noise. Results show that the noise magnitude is decreased both by reduction of domain size and the spectral nudging. However, the reduction of domain size alters some sensitivity signals. When spectral nudging is used significant alterations of the signal are not found. (orig.)

  1. Scaling plant ultraviolet spectral responses from laboratory action spectra to field spectral weighting factors

    International Nuclear Information System (INIS)

    Flint, S.D.; Caldwell, M.M.

    1996-01-01

    Biological spectral weighting functions (BSWF) play a key role in calculating the increase of biologically effective solar ultraviolet-B radiation (UV-BBE) due to ozone reduction, assessing current latitudinal gradients of UV-B BE . and comparing solar UV-B BE with that from lamps and filters in plant experiments. Plant UV action spectra (usually determined with monochromatic radiation in the laboratory with exposure periods on the order of hours) are often used as BSWF. The realism of such spectra for plants growing day after day in polychromatic solar radiation in the field is questionable. We tested the widely used generalized plant action spectrum since preliminary data from an action spectrum being developed with monochromatic radiation for a cultivated oat variety indicate reasonable agreement with the generalized spectrum. These tests involved exposing plants to polychromatic radiation either from a high-pressure xenon arc lamp in growth chambers or in the field under solar radiation with supplemental UV-B lamps. Different broad-spectrum combinations were achieved by truncating the spectrum at successively longer UV wavelengths with various filters. In the growth chamber experiments, the generalized plant spectrum appeared to predict plant growth responses at short (<310nm) wavelengths but not at longer wavelengths. The field experiment reinforced these conclusions, showing (in addition to the expected direct UV-B effects) both direct UV-A effects and UV-A mitigation of UV-B effects. (author)

  2. Fermentation process tracking through enhanced spectral calibration modeling.

    Science.gov (United States)

    Triadaphillou, Sophia; Martin, Elaine; Montague, Gary; Norden, Alison; Jeffkins, Paul; Stimpson, Sarah

    2007-06-15

    The FDA process analytical technology (PAT) initiative will materialize in a significant increase in the number of installations of spectroscopic instrumentation. However, to attain the greatest benefit from the data generated, there is a need for calibration procedures that extract the maximum information content. For example, in fermentation processes, the interpretation of the resulting spectra is challenging as a consequence of the large number of wavelengths recorded, the underlying correlation structure that is evident between the wavelengths and the impact of the measurement environment. Approaches to the development of calibration models have been based on the application of partial least squares (PLS) either to the full spectral signature or to a subset of wavelengths. This paper presents a new approach to calibration modeling that combines a wavelength selection procedure, spectral window selection (SWS), where windows of wavelengths are automatically selected which are subsequently used as the basis of the calibration model. However, due to the non-uniqueness of the windows selected when the algorithm is executed repeatedly, multiple models are constructed and these are then combined using stacking thereby increasing the robustness of the final calibration model. The methodology is applied to data generated during the monitoring of broth concentrations in an industrial fermentation process from on-line near-infrared (NIR) and mid-infrared (MIR) spectrometers. It is shown that the proposed calibration modeling procedure outperforms traditional calibration procedures, as well as enabling the identification of the critical regions of the spectra with regard to the fermentation process.

  3. Image enhancement by spectral-error correction for dual-energy computed tomography.

    Science.gov (United States)

    Park, Kyung-Kook; Oh, Chang-Hyun; Akay, Metin

    2011-01-01

    Dual-energy CT (DECT) was reintroduced recently to use the additional spectral information of X-ray attenuation and aims for accurate density measurement and material differentiation. However, the spectral information lies in the difference between low and high energy images or measurements, so that it is difficult to acquire accurate spectral information due to amplification of high pixel noise in the resulting difference image. In this work, an image enhancement technique for DECT is proposed, based on the fact that the attenuation of a higher density material decreases more rapidly as X-ray energy increases. We define as spectral error the case when a pixel pair of low and high energy images deviates far from the expected attenuation trend. After analyzing the spectral-error sources of DECT images, we propose a DECT image enhancement method, which consists of three steps: water-reference offset correction, spectral-error correction, and anti-correlated noise reduction. It is the main idea of this work that makes spectral errors distributed like random noise over the true attenuation and suppressed by the well-known anti-correlated noise reduction. The proposed method suppressed noise of liver lesions and improved contrast between liver lesions and liver parenchyma in DECT contrast-enhanced abdominal images and their two-material decomposition.

  4. Radiochemical methods to enhance efficiency of α-spectral measurements

    International Nuclear Information System (INIS)

    Silkina, G.P.; Artem'ev, O.I.

    2001-01-01

    The paper describes possible ways to improve a plutonium radiochemical separation technique developed in the Khlopin Radium Institute and modify it to account for the site-specific features of samples from the former Semipalatinsk test site (STS) and enhance the alpha spectrometry efficiency.The paper describes possible ways to improve a plutonium radiochemical separation technique developed in the Khlopin Radium Institute and modify it to account for the site-specific features of samples from the former Semipalatinsk test site (STS) and enhance the alpha spectrometry efficiency. (author)

  5. Enhancement of diffusers BSDF accuracy: spectral features effect

    NARCIS (Netherlands)

    Brug, H. van; Courrèges-Lacoste, G.B.; Otter, G.C.J.; Schaarsberg, J.G.; Delwart, S.; Del Bello, U.

    2006-01-01

    This paper reports the activities performed in the framework of the ESA contract 18432/04/NL/AR: Enhancement of diffusers BSDF Accuracy. This study was conducted to investigate properties of various diffusers. Diffusers are widely used in space instruments as part of the on-board absolute

  6. Concentric circular ring and nanodisk optical antenna enhanced multispectral quantum dot infrared photodetector with spectral localization

    International Nuclear Information System (INIS)

    Zhang, Yingjie; Kemsri, Thitikorn; Li, Lin; Lu, Xuejun; Gu, Guiru

    2017-01-01

    In this paper, we report a concentric circular ring and nanodisk plasmonic optical antenna (POA) enhanced multispectral quantum dot infrared photodetector (QDIP). The circular ring and the nanodisk POA structures are designed to have plasmonic resonant wavelengths in the longwave infrared (LWIR) and the midwave infrared (MWIR) spectral regimes, respectively. The electric field ( E -field) distributions are simulated and show spectral localization due to the distinct plasmonic resonant wavelengths of the POA structures. The circular ring is found to enhance the E -fields in the nanodisk regions due to the mutual coupling. A concentric circular ring and nanodisk POA enhanced multispectral QDIP was fabricated and tested. Multispectral enhancement was observed. The enhancement is compared to that of a QDIP with only the circular ring POA structure. The experiment data agree with the simulation. The concentric circular ring and nanodisk POA provides a compact planar structure for multispectral QDIP enhancement. (paper)

  7. Spectral response of multi-element silicon detectors

    Energy Technology Data Exchange (ETDEWEB)

    Ludewigt, B.A.; Rossington, C.S.; Chapman, K. [Univ. of California, Berkeley, CA (United States)

    1997-04-01

    Multi-element silicon strip detectors, in conjunction with integrated circuit pulse-processing electronics, offer an attractive alternative to conventional lithium-drifted silicon Si(Li) and high purity germanium detectors (HPGe) for high count rate, low noise synchrotron x-ray fluorescence applications. One of the major differences between the segmented Si detectors and the commercially available single-element Si(Li) or HPGe detectors is that hundreds of elements can be fabricated on a single Si substrate using standard silicon processing technologies. The segmentation of the detector substrate into many small elements results in very low noise performance at or near, room temperature, and the count rate of the detector is increased many-fold due to the multiplication in the total number of detectors. Traditionally, a single channel of detector with electronics can handle {approximately}100 kHz count rates while maintaining good energy resolution; the segmented detectors can operate at greater than MHz count rates merely due to the multiplication in the number of channels. One of the most critical aspects in the development of the segmented detectors is characterizing the charge sharing and charge loss that occur between the individual detector strips, and determining how these affect the spectral response of the detectors.

  8. Correlation of contrast agent kinetics between iodinated contrast-enhanced spectral tomosynthesis and gadolinium-enhanced MRI of breast lesions

    International Nuclear Information System (INIS)

    Froeling, Vera; Diekmann, Felix; Renz, Diane M.; Fallenberg, Eva M.; Steffen, Ingo G.; Diekmann, Susanne; Schmitzberger, Florian F.; Lawaczeck, Ruediger

    2013-01-01

    Assessment of contrast agent kinetics in contrast-enhanced MRI (CE-MRI) with gadolinium-containing contrast agents offers the opportunity to predict breast lesion malignancy. The goal of our study was to determine if similar patterns exist for spectral contrast-enhanced digital breast tomosynthesis (CE-DBT) using an iodinated contrast agent. The protocol of our prospective study was approved by the relevant institutional review board and the German Federal Office for Radiation Protection. All patients provided written informed consent. We included 21 women with a mean age of 62.4 years. All underwent ultrasound-guided biopsy of a suspect breast lesion, spectral CE-DBT and CE-MRI. For every breast lesion, contrast agent kinetics was assessed by signal intensity-time curves for spectral CE-DBT and CE-MRI. Statistical comparison used Cohen's kappa and Spearman's rho test. Spearman's rho of 0.49 showed significant (P = 0.036) correlation regarding the contrast agent kinetics in signal intensity-time curves for spectral CE-DBT and CE-MRI. Cohen's kappa indicated moderate agreement (kappa = 0.438). There is a statistically significant correlation between contrast agent kinetics in the signal intensity-time curves for spectral CE-DBT and CE-MRI. Observing intralesional contrast agent kinetics in spectral CE-DBT may aid evaluation of malignant breast lesions. (orig.)

  9. Contrast-enhanced spectral mammography (CESM) and contrast enhanced MRI (CEMRI): Patient preferences and tolerance.

    Science.gov (United States)

    Hobbs, Max M; Taylor, Donna B; Buzynski, Sebastian; Peake, Rachel E

    2015-06-01

    Contrast-enhanced spectral mammography (CESM) may have similar diagnostic performance to Contrast-enhanced MRI (CEMRI) in the diagnosis and staging of breast cancer. To date, research has focused exclusively on diagnostic performance when comparing these two techniques. Patient experience is also an important factor when comparing and deciding on which of these modalities is preferable. The aim of this study is to compare patient experience of CESM against CEMRI during preoperative breast cancer staging. Forty-nine participants who underwent both CESM and CEMRI, as part of a larger trial, completed a Likert questionnaire about their preference for each modality according to the following criteria: comfort of breast compression, comfort of intravenous (IV) contrast injection, anxiety and overall preference. Participants also reported reasons for preferring one modality to the other. Quantitative data were analysed using a Wilcoxon sign-rank test and chi-squared test. Qualitative data are reported descriptively. A significantly higher overall preference towards CESM was demonstrated (n = 49, P < 0.001), with faster procedure time, greater comfort and lower noise level cited as the commonest reasons. Participants also reported significantly lower rates of anxiety during CESM compared with CEMRI (n = 36, P = 0.009). A significantly higher rate of comfort was reported during CEMRI for measures of breast compression (n = 49, P = 0.001) and the sensation of IV contrast injection (n = 49, P = 0.003). Our data suggest that overall, patients prefer the experience of CESM to CEMRI, adding support for the role of CESM as a possible alternative to CEMRI for breast cancer staging. © 2015 The Royal Australian and New Zealand College of Radiologists.

  10. Contrast-enhanced spectral mammography (CESM) and contrast enhanced MRI (CEMRI): Patient preferences and tolerance

    International Nuclear Information System (INIS)

    Hobbs, Max; Buzynski, Sebastian; Taylor, Donna B.; Peake, Rachel E.

    2015-01-01

    Contrast-enhanced spectral mammography (CESM) may have similar diagnostic performance to Contrast-enhanced MRI (CEMRI) in the diagnosis and staging of breast cancer. To date, research has focused exclusively on diagnostic performance when comparing these two techniques. Patient experience is also an important factor when comparing and deciding on which of these modalities is preferable. The aim of this study is to compare patient experience of CESM against CEMRI during preoperative breast cancer staging. Forty-nine participants who underwent both CESM and CEMRI, as part of a larger trial, completed a Likert questionnaire about their preference for each modality according to the following criteria: comfort of breast compression, comfort of intravenous (IV) contrast injection, anxiety and overall preference. Participants also reported reasons for preferring one modality to the other. Quantitative data were analysed using a Wilcoxon sign-rank test and chi-squared test. Qualitative data are reported descriptively. A significantly higher overall preference towards CESM was demonstrated (n = 49, P < 0.001), with faster procedure time, greater comfort and lower noise level cited as the commonest reasons. Participants also reported significantly lower rates of anxiety during CESM compared with CEMRI (n = 36, P = 0.009). A significantly higher rate of comfort was reported during CEMRI for measures of breast compression (n = 49, P = 0.001) and the sensation of IV contrast injection (n = 49, P = 0.003). Our data suggest that overall, patients prefer the experience of CESM to CEMRI, adding support for the role of CESM as a possible alternative to CEMRI for breast cancer staging.

  11. Signal enhancement by spectral equalization of high frequency broadband signals transmitted through optical fibers

    International Nuclear Information System (INIS)

    Lyons, P.B.; Ogle, J.W.; Holzman, M.A.

    1980-01-01

    A new technique is discussed for enhancing the bandwidth and intensity of high frequency (> 1 GHz) analog, spectrally broad (40 nm) signals transmitted through one kilometer of optical fiber. The existing method for bandwidth enhancement of such a signal uses a very narrow (approx. 1 nm) filter between the fiber and detector to limit bandwidth degradation due to material dispersion. Using this method, most of the available optical intensity is rejected and lost. This new technique replaces the narrow-band filter with a spectral equalizer device which uses a reflection grating to disperse the input signal spectrum and direct it onto a linear array of fibers

  12. Spectral induced polarization (SIP) response of mine tailings.

    Science.gov (United States)

    Placencia-Gómez, Edmundo; Parviainen, Annika; Slater, Lee; Leveinen, Jussi

    2015-02-01

    Mine tailings impoundments are a source of leachates known as acid mine drainage (AMD) which can pose a contamination risk for surrounding surface and groundwater. Methodologies which can help management of this environmental issue are needed. We carried out a laboratory study of the spectral induced polarization (SIP) response of tailings from the Haveri Au-Cu mine, SW Finland. The primary objectives were, (1) to determine possible correlations between SIP parameters and textural properties associated with oxidative-weathering mechanisms, mineralogical composition and metallic content, and (2) to evaluate the effects of the pore water chemistry on SIP parameters associated with redox-inactive and redox-active electrolytes varying in molar concentration, conductivity and pH. The Haveri tailings exhibit well defined relaxation spectra between 100 and 10,000Hz. The relaxation magnitudes are governed by the in-situ oxidative-weathering conditions on sulphide mineral surfaces contained in the tailings, and decrease with the oxidation degree. The oxidation-driven textural variation in the tailings results in changes to the frequency peak of the phase angle, the imaginary conductivity and chargeability, when plotted versus the pore water conductivity. In contrast, the real and the formation electrical conductivity components show a single linear dependence on the pore water conductivity. The increase of the pore water conductivity (dominated by the increase of ions concentration in solution) along with a transition to acidic conditions shifts the polarization peak towards higher frequencies. These findings show the unique sensitivity of the SIP method to potentially discriminate AMD discharges from reactive oxidation zones in tailings, suggesting a significant advantage for monitoring threatened aquifers. Copyright © 2014 Elsevier B.V. All rights reserved.

  13. Digital simulation of staining in histopathology multispectral images: enhancement and linear transformation of spectral transmittance.

    Science.gov (United States)

    Bautista, Pinky A; Yagi, Yukako

    2012-05-01

    Hematoxylin and eosin (H&E) stain is currently the most popular for routine histopathology staining. Special and/or immuno-histochemical (IHC) staining is often requested to further corroborate the initial diagnosis on H&E stained tissue sections. Digital simulation of staining (or digital staining) can be a very valuable tool to produce the desired stained images from the H&E stained tissue sections instantaneously. We present an approach to digital staining of histopathology multispectral images by combining the effects of spectral enhancement and spectral transformation. Spectral enhancement is accomplished by shifting the N-band original spectrum of the multispectral pixel with the weighted difference between the pixel's original and estimated spectrum; the spectrum is estimated using M transformed to the spectral configuration associated to its reaction to a specific stain by utilizing an N × N transformation matrix, which is derived through application of least mean squares method to the enhanced and target spectral transmittance samples of the different tissue components found in the image. Results of our experiments on the digital conversion of an H&E stained multispectral image to its Masson's trichrome stained equivalent show the viability of the method.

  14. Spectrally enhanced image resolution of tooth enamel surfaces

    Science.gov (United States)

    Zhang, Liang; Nelson, Leonard Y.; Berg, Joel H.; Seibel, Eric J.

    2012-01-01

    Short-wavelength 405 nm laser illumination of surface dental enamel using an ultrathin scanning fiber endoscope (SFE) produced enhanced detail of dental topography. The surfaces of human extracted teeth and artificial erosions were imaged with 405 nm, 444 nm, 532 nm, or 635 nm illumination lasers. The obtained images were then processed offline to compensate for any differences in the illumination beam diameters between the different lasers. Scattering and absorption coefficients for a Monte Carlo model of light propagation in dental enamel for 405 nm were scaled from published data at 532 nm and 633 nm. The value of the scattering coefficient used in the model was scaled from the coefficients at 532 nm and 633 nm by the inverse third power of wavelength. Simulations showed that the penetration depth of short-wavelength illumination is localized close to the enamel surface, while long-wavelength illumination travels much further and is backscattered from greater depths. Therefore, images obtained using short wavelength laser are not contaminated by the superposition of light reflected from enamel tissue at greater depths. Hence, the SFE with short-wavelength illumination may make it possible to visualize surface manifestations of phenomena such as demineralization, thus better aiding the clinician in the detection of early caries.

  15. Spectral response variation of a negative-electron-affinity photocathode in the preparation process

    International Nuclear Information System (INIS)

    Liu Lei; Du Yujie; Chang Benkang; Yunsheng Qian

    2006-01-01

    In order to research the spectral response variation of a negative electron affinity (NEA) photocathode in the preparation process, we have done two experiments on a transmission-type GaAs photocathode.First, an automatic spectral response recording system is described, which is used to take spectral response curves during the activation procedure of the photocathode. By this system, the spectral response curves of a GaAs:Cs-Ophotocathode measured in situ are presented. Then, after the cathode is sealed with a microchannel plate and a fluorescence screen into the image tube, we measure the spectral response of the tube by another measurement instrument. By way of comparing and analyzing these curves, we can find the typical variation in spectral-responses.The reasons for the variation are discussed. Based on these curves, spectral matching factors of a GaAs cathode for green vegetation and rough concrete are calculated. The visual ranges of night-vision goggles under specific circumstances are estimated. The results show that the spectral response of the NEA photocathode degraded in the sealing process, especially at long wavelengths. The variation has also influenced the whole performance of the intensifier tube

  16. Effect of gold photocathode contamination on a flat spectral response X-ray diode

    Science.gov (United States)

    Wang, Kun-lun; Zhang, Si-qun; Zhou, Shao-tong; Huang, Xian-bin; Ren, Xiao-dong; Dan, Jia-kun; Xu, Qiang

    2018-03-01

    A detector with an approximately flat spectral response is important for diagnosing intense thermal X-ray flux. A flat-spectral-response X-ray diode (FSR-XRD) utilizes a gold photocathode X-ray diode and a specially configured gold filter to give rise to a nearly flat spectral response in the photon energy range of 100-4000 eV. It has been observed that the spectral responses of several FSR-XRDs changed after a few shots of z-pinch experiments on the Primary Test Stand facility. This paper presents an analysis of the changes by fitting the spectral responses of the gold photocathodes using a model with a free parameter which characterizes the thickness of the contamination. The spectral responses of FSR-XRDs were calibrated with synchrotron radiation, and several cleaning methods were tested with the calibration. Considering the results of model and cleaning, it may be anticipated that contamination was the major reason of the response changing. Contamination worsened the flatness of the spectral response of the FSR-XRD and decreased the averaged response, hence it is important to avoid contamination. Current results indicate a requirement of further study of the contamination.

  17. Contrast-enhanced spectral mammography in neoadjuvant chemotherapy monitoring: a comparison with breast magnetic resonance imaging.

    Science.gov (United States)

    Iotti, Valentina; Ravaioli, Sara; Vacondio, Rita; Coriani, Chiara; Caffarri, Sabrina; Sghedoni, Roberto; Nitrosi, Andrea; Ragazzi, Moira; Gasparini, Elisa; Masini, Cristina; Bisagni, Giancarlo; Falco, Giuseppe; Ferrari, Guglielmo; Braglia, Luca; Del Prato, Alberto; Malavolti, Ivana; Ginocchi, Vladimiro; Pattacini, Pierpaolo

    2017-09-11

    Neoadjuvant-chemotherapy (NAC) is considered the standard treatment for locally advanced breast carcinomas. Accurate assessment of disease response is fundamental to increase the chances of successful breast-conserving surgery and to avoid local recurrence. The purpose of this study was to compare contrast-enhanced spectral mammography (CESM) and contrast-enhanced-MRI (MRI) in the evaluation of tumor response to NAC. This prospective study was approved by the institutional review board and written informed consent was obtained. Fifty-four consenting women with breast cancer and indication of NAC were consecutively enrolled between October 2012 and December 2014. Patients underwent both CESM and MRI before, during and after NAC. MRI was performed first, followed by CESM within 3 days. Response to therapy was evaluated for each patient, comparing the size of the residual lesion measured on CESM and MRI performed after NAC to the pathological response on surgical specimens (gold standard), independently of and blinded to the results of the other test. The agreement between measurements was evaluated using Lin's coefficient. The agreement between measurements using CESM and MRI was tested at each step of the study, before, during and after NAC. And last of all, the variation in the largest dimension of the tumor on CESM and MRI was assessed according to the parameters set in RECIST 1.1 criteria, focusing on pathological complete response (pCR). A total of 46 patients (85%) completed the study. CESM predicted pCR better than MRI (Lin's coefficient 0.81 and 0.59, respectively). Both methods tend to underestimate the real extent of residual tumor (mean 4.1mm in CESM, 7.5mm in MRI). The agreement between measurements using CESM and MRI was 0.96, 0.94 and 0.76 before, during and after NAC respectively. The distinction between responders and non-responders with CESM and MRI was identical for 45/46 patients. In the assessment of CR, sensitivity and specificity were 100% and

  18. Stability of the spectral responsivity of cryogenically cooled InSb infrared detectors

    International Nuclear Information System (INIS)

    Theocharous, Evangelos

    2005-01-01

    The spectral responsivity of two cryogenically cooled InSb detectors was observed to drift slowly with time. The origin of these drifts was investigated and was shown to occur due to a water-ice thin film that was deposited onto the active areas of the cold detectors. The presence of the ice film (which is itself a dielectric film) modifies the transmission characteristics of the antireflection coatings deposited on the active areas of the detectors, thus giving rise to the observed drifts. The magnitude of the drifts was drastically reduced by evacuating the detector dewars while baking them at 50 deg. C for approximately 48 h. All InSb detectors have antireflection coatings to reduce the Fresnel reflections and therefore enhance their spectral responsivity. This work demonstrates that InSb infrared detectors should be evacuated and baked at least annually and in some cases (depending on the quality of the dewar and the measurement uncertainty required) more frequently. These observations are particularly relevant to InSb detectors mounted in dewars that use rubber O rings since the ingress of moisture was found to be particularly serious in this type of dewar

  19. Comparisons of spectrally-enhanced asymmetrically-clipped optical OFDM systems.

    Science.gov (United States)

    Lowery, Arthur James

    2016-02-22

    Asymmetrically clipped optical orthogonal frequency-division multiplexing (ACO-OFDM) is a technique that sacrifices spectral efficiency in order to transmit an orthogonally frequency-division multiplexed signal over a unipolar channel, such as a directly modulated direct-detection fiber or free-space channel. Several methods have been proposed to regain this spectral efficiency, including: asymmetrically clipped DC-biased optical OFDM (ADO-OFDM), enhanced U-OFDM (EU-OFDM), spectral and energy efficient OFDM (SEE-OFDM), Hybrid-ACO-OFDM and Layered-ACO-OFDM. This paper presents simulations up to high-order constellation sizes to show that Layered-ACO-OFDM offers the highest receiver sensitivity for a given optical power at spectral efficiencies above 3 bit/s/Hz. For comparison purposes, white Gaussian noise is added at the receiver, component nonlinearities are not considered, and the fiber is considered to be linear and dispersion-less. The simulations show that LACO-OFDM has a 7-dB sensitivity advantage over DC-biased OFDM (DCO-OFDM) for 1024-QAM at 87.5% of DCO-OFDM's spectral efficiency, at the same bit rate and optical power. This is approximately equivalent to a 4.4-dB advantage at the same spectral efficiency of 87.7% if 896-QAM were to be used for DCO-OFDM.

  20. Simulating charge transport to understand the spectral response of Swept Charge Devices

    Science.gov (United States)

    Athiray, P. S.; Sreekumar, P.; Narendranath, S.; Gow, J. P. D.

    2015-11-01

    Context. Swept Charge Devices (SCD) are novel X-ray detectors optimized for improved spectral performance without any demand for active cooling. The Chandrayaan-1 X-ray Spectrometer (C1XS) experiment onboard the Chandrayaan-1 spacecraft used an array of SCDs to map the global surface elemental abundances on the Moon using the X-ray fluorescence (XRF) technique. The successful demonstration of SCDs in C1XS spurred an enhanced version of the spectrometer on Chandrayaan-2 using the next-generation SCD sensors. Aims: The objective of this paper is to demonstrate validation of a physical model developed to simulate X-ray photon interaction and charge transportation in a SCD. The model helps to understand and identify the origin of individual components that collectively contribute to the energy-dependent spectral response of the SCD. Furthermore, the model provides completeness to various calibration tasks, such as generating spectral matrices (RMFs - redistribution matrix files), estimating efficiency, optimizing event selection logic, and maximizing event recovery to improve photon-collection efficiency in SCDs. Methods: Charge generation and transportation in the SCD at different layers related to channel stops, field zones, and field-free zones due to photon interaction were computed using standard drift and diffusion equations. Charge collected in the buried channel due to photon interaction in different volumes of the detector was computed by assuming a Gaussian radial profile of the charge cloud. The collected charge was processed further to simulate both diagonal clocking read-out, which is a novel design exclusive for SCDs, and event selection logic to construct the energy spectrum. Results: We compare simulation results of the SCD CCD54 with measurements obtained during the ground calibration of C1XS and clearly demonstrate that our model reproduces all the major spectral features seen in calibration data. We also describe our understanding of interactions at

  1. Spectrally adjustable quasi-monochromatic radiance source based on LEDs and its application for measuring spectral responsivity of a luminance meter

    International Nuclear Information System (INIS)

    Hirvonen, Juha-Matti; Poikonen, Tuomas; Vaskuri, Anna; Kärhä, Petri; Ikonen, Erkki

    2013-01-01

    A spectrally adjustable radiance source based on light-emitting diodes (LEDs) has been constructed for spectral responsivity measurements of radiance and luminance meters. A 300 mm integrating sphere source with adjustable output port is illuminated using 30 thermally stabilized narrow-band LEDs covering the visible wavelength range of 380–780 nm. The functionality of the measurement setup is demonstrated by measuring the relative spectral responsivities of a luminance meter and a photometer head with cosine-corrected input optics. (paper)

  2. Contrast-enhanced spectral mammography with a photon-counting detector.

    Science.gov (United States)

    Fredenberg, Erik; Hemmendorff, Magnus; Cederström, Björn; Aslund, Magnus; Danielsson, Mats

    2010-05-01

    Spectral imaging is a method in medical x-ray imaging to extract information about the object constituents by the material-specific energy dependence of x-ray attenuation. The authors have investigated a photon-counting spectral imaging system with two energy bins for contrast-enhanced mammography. System optimization and the potential benefit compared to conventional non-energy-resolved absorption imaging was studied. A framework for system characterization was set up that included quantum and anatomical noise and a theoretical model of the system was benchmarked to phantom measurements. Optimal combination of the energy-resolved images corresponded approximately to minimization of the anatomical noise, which is commonly referred to as energy subtraction. In that case, an ideal-observer detectability index could be improved close to 50% compared to absorption imaging in the phantom study. Optimization with respect to the signal-to-quantum-noise ratio, commonly referred to as energy weighting, yielded only a minute improvement. In a simulation of a clinically more realistic case, spectral imaging was predicted to perform approximately 30% better than absorption imaging for an average glandularity breast with an average level of anatomical noise. For dense breast tissue and a high level of anatomical noise, however, a rise in detectability by a factor of 6 was predicted. Another approximately 70%-90% improvement was found to be within reach for an optimized system. Contrast-enhanced spectral mammography is feasible and beneficial with the current system, and there is room for additional improvements. Inclusion of anatomical noise is essential for optimizing spectral imaging systems.

  3. Contrast-enhanced spectral mammography with a photon-counting detector

    Energy Technology Data Exchange (ETDEWEB)

    Fredenberg, Erik; Hemmendorff, Magnus; Cederstroem, Bjoern; Aaslund, Magnus; Danielsson, Mats [Department of Physics, Royal Institute of Technology, AlbaNova, SE-106 91 Stockholm (Sweden); Sectra Mamea AB, Smidesvaegen 5, SE-171 41 Solna (Sweden); Department of Physics, Royal Institute of Technology, AlbaNova, SE-106 91 Stockholm (Sweden); Sectra Mamea AB, Smidesvaegen 5, SE-171 41 Solna (Sweden); Department of Physics, Royal Institute of Technology, AlbaNova, SE-106 91 Stockholm (Sweden)

    2010-05-15

    Purpose: Spectral imaging is a method in medical x-ray imaging to extract information about the object constituents by the material-specific energy dependence of x-ray attenuation. The authors have investigated a photon-counting spectral imaging system with two energy bins for contrast-enhanced mammography. System optimization and the potential benefit compared to conventional non-energy-resolved absorption imaging was studied. Methods: A framework for system characterization was set up that included quantum and anatomical noise and a theoretical model of the system was benchmarked to phantom measurements. Results: Optimal combination of the energy-resolved images corresponded approximately to minimization of the anatomical noise, which is commonly referred to as energy subtraction. In that case, an ideal-observer detectability index could be improved close to 50% compared to absorption imaging in the phantom study. Optimization with respect to the signal-to-quantum-noise ratio, commonly referred to as energy weighting, yielded only a minute improvement. In a simulation of a clinically more realistic case, spectral imaging was predicted to perform approximately 30% better than absorption imaging for an average glandularity breast with an average level of anatomical noise. For dense breast tissue and a high level of anatomical noise, however, a rise in detectability by a factor of 6 was predicted. Another {approx}70%-90% improvement was found to be within reach for an optimized system. Conclusions: Contrast-enhanced spectral mammography is feasible and beneficial with the current system, and there is room for additional improvements. Inclusion of anatomical noise is essential for optimizing spectral imaging systems.

  4. Correlation between blood and lymphatic vessel density and results of contrast-enhanced spectral mammography.

    Science.gov (United States)

    Luczynska, Elzbieta; Niemiec, Joanna; Ambicka, Aleksandra; Adamczyk, Agnieszka; Walasek, Tomasz; Ryś, Janusz; Sas-Korczyńska, Beata

    2015-09-01

    Contrast-enhanced spectral mammography (CESM) is a novel technique used for detection of tumour vascularity by imaging the moment in which contrast, delivered to the lesion by blood vessels, leaks out of them, and flows out through lymphatic vessels. In our study, we included 174 women for whom spectral mammography was performed for diagnostic purposes. The relationship between enhancement in CESM and blood vessel density (BVD), lymphatic vessel density (LVD) or the percentage of fields with at least one lymphatic vessel (distribution of podoplanin-positive vessels - DPV) and other related parameters was assessed in 55 cases. BVD, LVD and DPV were assessed immunohistochemically, applying podoplanin and CD31/CD34 as markers of lymphatic and blood vessels, respectively. The sensitivity (in detection of malignant lesions) of CESM was 100%, while its specificity - 39%. We found a significant positive correlation between the intensity of enhancement in CESM and BVD (p = 0.007, r = 0.357) and a negative correlation between the intensity of enhancement in CESM and DPV (p = 0.003, r = -0.390). Lesions with the highest enhancement in CESM showed a high number of blood vessels and a low number of lymphatics. 1) CESM is a method characterized by high sensitivity and acceptable specificity; 2) the correlation between CESM results and blood/lymphatic vessel density confirms its utility in detection of tissue angiogenesis and/or lymphangiogenesis.

  5. Multisensory integration produces an initial response enhancement

    Directory of Open Access Journals (Sweden)

    Benjamin A Rowland

    2007-11-01

    Full Text Available The brain has evolved the ability to integrate information across the senses in order to improve the detection and disambiguation of biologically significant events. This multisensory synthesis of information leads to faster (and more accurate behavioral responses, yet the underlying neural mechanisms by which these responses are speeded are as yet unclear. The aim of these experiments was to evaluate the temporal properties of multisensory enhancement in the physiological responses of neuron in the superior colliculus (SC. Of specific interest was the temporal evolution of their responses to individual modality-specific stimuli as well as to cross-modal combinations of these stimuli. The results demonstrate that cross-modal stimuli typically elicit faster, more robust, and more reliable physiological responses than do their modality-specific component stimuli. Response measures sensitive to the time domain showed that these multisensory responses were enhanced from their very onset, and that the acceleration of the enhancement was greatest within the first 40 ms (or 50% of the response. The latter half of the multisensory response was typically only as robust and informative as predicted by a linear combination of the unisensory component responses. These results may reveal some of the key physiological changes underlying many of the SC-mediated behavioral benefits of multisensory integration.

  6. Enhancement of absorption of lower hybrid wave by filling the spectral gap

    International Nuclear Information System (INIS)

    Ide, S.; Naito, O.; Kondoh, T.; Ikeda, Y.; Ushigusa, K.

    1994-01-01

    The interaction between a lower hybrid wave (LHW) and electrons in a plasma has been investigated. An LHW of low phase velocity was injected into a plasma in addition to a high phase velocity LHW so as to fill the spectral gap which lies between the phase velocity of the faster wave and the thermal velocity of the electrons. It was found that the absorption of the faster wave was enhanced at the plasma outer region by injecting these waves simultaneously. As a result LH-driven current in the inner region of the plasma was reduced by the power absorbed in the outer region. The increase of the power absorption is attributed to the filling of the spectral gap by the slower wave

  7. Hybrid Image Fusion for Sharpness Enhancement of Multi-Spectral Lunar Images

    Science.gov (United States)

    Awumah, Anna; Mahanti, Prasun; Robinson, Mark

    2016-10-01

    Image fusion enhances the sharpness of a multi-spectral (MS) image by incorporating spatial details from a higher-resolution panchromatic (Pan) image [1,2]. Known applications of image fusion for planetary images are rare, although image fusion is well-known for its applications to Earth-based remote sensing. In a recent work [3], six different image fusion algorithms were implemented and their performances were verified with images from the Lunar Reconnaissance Orbiter (LRO) Camera. The image fusion procedure obtained a high-resolution multi-spectral (HRMS) product from the LRO Narrow Angle Camera (used as Pan) and LRO Wide Angle Camera (used as MS) images. The results showed that the Intensity-Hue-Saturation (IHS) algorithm results in a high-spatial quality product while the Wavelet-based image fusion algorithm best preserves spectral quality among all the algorithms. In this work we show the results of a hybrid IHS-Wavelet image fusion algorithm when applied to LROC MS images. The hybrid method provides the best HRMS product - both in terms of spatial resolution and preservation of spectral details. Results from hybrid image fusion can enable new science and increase the science return from existing LROC images.[1] Pohl, Cle, and John L. Van Genderen. "Review article multisensor image fusion in remote sensing: concepts, methods and applications." International journal of remote sensing 19.5 (1998): 823-854.[2] Zhang, Yun. "Understanding image fusion." Photogramm. Eng. Remote Sens 70.6 (2004): 657-661.[3] Mahanti, Prasun et al. "Enhancement of spatial resolution of the LROC Wide Angle Camera images." Archives, XXIII ISPRS Congress Archives (2016).

  8. Spectral response, dark current, and noise analyses in resonant tunneling quantum dot infrared photodetectors.

    Science.gov (United States)

    Jahromi, Hamed Dehdashti; Mahmoodi, Ali; Sheikhi, Mohammad Hossein; Zarifkar, Abbas

    2016-10-20

    Reduction of dark current at high-temperature operation is a great challenge in conventional quantum dot infrared photodetectors, as the rate of thermal excitations resulting in the dark current increases exponentially with temperature. A resonant tunneling barrier is the best candidate for suppression of dark current, enhancement in signal-to-noise ratio, and selective extraction of different wavelength response. In this paper, we use a physical model developed by the authors recently to design a proper resonant tunneling barrier for quantum infrared photodetectors and to study and analyze the spectral response of these devices. The calculated transmission coefficient of electrons by this model and its dependency on bias voltage are in agreement with experimental results. Furthermore, based on the calculated transmission coefficient, the dark current of a quantum dot infrared photodetector with a resonant tunneling barrier is calculated and compared with the experimental data. The validity of our model is proven through this comparison. Theoretical dark current by our model shows better agreement with the experimental data and is more accurate than the previously developed model. Moreover, noise in the device is calculated. Finally, the effect of different parameters, such as temperature, size of quantum dots, and bias voltage, on the performance of the device is simulated and studied.

  9. The added value of contrast enhanced spectral mammography in identification of multiplicity of suspicious lesions in dense breast

    Directory of Open Access Journals (Sweden)

    Amr Farouk Ibrahim Moustafa

    2018-03-01

    Full Text Available Objective: To evaluate the additive value of Contrast Enhanced Spectral Mammography (CESM in the preoperative assessment of malignant lesions in dense breast parenchyma regarding multiplicity. Material and methods: The study included 160 women having heterogeneous dense breast parenchyma (ACR c and d with suspicious lesions identified on sono mammography examination. All patients performed contrast enhanced spectral mammography to confirm or exclude lesion multiplicity. The number of lesions was calculated in the contrast high energy subtraction images with the reference standard being histopathological analysis. Results: Adding CESM to sono-mammography the accuracy in identifying multiple malignant lesion increased from 81.8% accuracy of sono-mammography up to 100% accuracy after adding CESM. Conclusion: Contrast enhanced spectral mammogram showed an added value in the preoperative assessment of breast masses increasing the accuracy of detection of lesions and multiplicity (multifocality and multi-centricity. Keywords: Breast cancer, Contrast enhanced spectral mammogram

  10. Contrast-Enhanced Spectral Mammography: Comparison with Conventional Mammography and Histopathology in 152 Women

    OpenAIRE

    Luczyńska, Elzbieta; Heinze-Paluchowska, Sylwia; Dyczek, Sonia; Blecharz, Pawel; Rys, Janusz; Reinfuss, Marian

    2014-01-01

    Objective The goal of the study was to compare conventional mammography (MG) and contrast-enhanced spectral mammography (CESM) in preoperative women. Materials and Methods The study was approved by the local Ethics Committee and all participants provided informed consent. The study included 152 consecutive patients with 173 breast lesions diagnosed on MG or CESM. All MG examinations and consults were conducted in one oncology centre. Non-ionic contrast agent, at a total dose of 1.5 mL/kg body...

  11. Visual perception enhancement for detection of cancerous oral tissue by multi-spectral imaging

    International Nuclear Information System (INIS)

    Wang, Hsiang-Chen; Tsai, Meng-Tsan; Chiang, Chun-Ping

    2013-01-01

    Color reproduction systems based on the multi-spectral imaging technique (MSI) for both directly estimating reflection spectra and direct visualization of oral tissues using various light sources are proposed. Images from three oral cancer patients were taken as the experimental samples, and spectral differences between pre-cancerous and normal oral mucosal tissues were calculated at three time points during 5-aminolevulinic acid photodynamic therapy (ALA-PDT) to analyze whether they were consistent with disease processes. To check the successful treatment of oral cancer with ALA-PDT, oral cavity images by swept source optical coherence tomography (SS-OCT) are demonstrated. This system can also reproduce images under different light sources. For pre-cancerous detection, the oral images after the second ALA-PDT are assigned as the target samples. By using RGB LEDs with various correlated color temperatures (CCTs) for color difference comparison, the light source with a CCT of about 4500 K was found to have the best ability to enhance the color difference between pre-cancerous and normal oral mucosal tissues in the oral cavity. Compared with the fluorescent lighting commonly used today, the color difference can be improved by 39.2% from 16.5270 to 23.0023. Hence, this light source and spectral analysis increase the efficiency of the medical diagnosis of oral cancer and aid patients in receiving early treatment. (paper)

  12. Visual perception enhancement for detection of cancerous oral tissue by multi-spectral imaging

    Science.gov (United States)

    Wang, Hsiang-Chen; Tsai, Meng-Tsan; Chiang, Chun-Ping

    2013-05-01

    Color reproduction systems based on the multi-spectral imaging technique (MSI) for both directly estimating reflection spectra and direct visualization of oral tissues using various light sources are proposed. Images from three oral cancer patients were taken as the experimental samples, and spectral differences between pre-cancerous and normal oral mucosal tissues were calculated at three time points during 5-aminolevulinic acid photodynamic therapy (ALA-PDT) to analyze whether they were consistent with disease processes. To check the successful treatment of oral cancer with ALA-PDT, oral cavity images by swept source optical coherence tomography (SS-OCT) are demonstrated. This system can also reproduce images under different light sources. For pre-cancerous detection, the oral images after the second ALA-PDT are assigned as the target samples. By using RGB LEDs with various correlated color temperatures (CCTs) for color difference comparison, the light source with a CCT of about 4500 K was found to have the best ability to enhance the color difference between pre-cancerous and normal oral mucosal tissues in the oral cavity. Compared with the fluorescent lighting commonly used today, the color difference can be improved by 39.2% from 16.5270 to 23.0023. Hence, this light source and spectral analysis increase the efficiency of the medical diagnosis of oral cancer and aid patients in receiving early treatment.

  13. Biocrust spectral response as affected by changing climatic conditions

    Science.gov (United States)

    Rodriguez-Caballero, Emilio; Guirado, Emilio; Escribano, Paula; Reyes, Andres; Weber, Bettina

    2017-04-01

    Drylands are characterized by scarce vegetation coverage and low rates of biological activity, both constrained by water scarcity. Under these conditions, biocrusts form key players of ecosystem functioning. They comprise complex poikilohydric communities of cyanobacteria, algae, lichens and bryophytes together with heterotrophic bacteria, archaea and fungi, which cover the uppermost soil layer. Biocrusts can cope with prolonged phases of drought, being rapidly re-activated when water becomes available again. Upon reactivation, biocrusts almost immediately turn green, fixing atmospheric carbon and nitrogen and increasing ecosystem productivity. However, due to their inconspicuous growth they have only rarely been analysed and spatially and temporally continuous information on their response to water pulses is missing. These data are particularly important under changing climatic conditions predicting an increase in aridity and variations in precipitation patterns within most of the dryland regions. In the present study, we used multi-temporal series of NDVI obtained from LANDSAT images to analyze biocrust and vegetation response to water pulses within the South African Succulent Karoo and we predicted their future response under different climate change scenarios. The results showed that biocrust and vegetation greenness are controlled by aridity, solar radiation and soil water content, showing similar annual patterns, with minimum values during dry periods that increased within the rainy season and decreased again after the onset of drought. However, biocrusts responded faster to water availability and turned green almost immediately after small rains, producing a small NDVI peak only few days after rainfall, whereas more time was needed for vegetation to grow new green tissue. However, once the photosynthetic tissue of vegetation was restored, it caused the highest increase of NDVI values after the rain. Predicted changes in precipitation patterns and aridity

  14. Spectral resolution enhancement of Fourier-transform spectrometer based on orthogonal shear interference using Wollaston prism

    Science.gov (United States)

    Cong, Lin-xiao; Huang, Min; Cai, Qi-sheng

    2017-10-01

    In this paper, a multi-line interferogram stitching method based on orthogonal shear using the Wollaston prism(WP) was proposed with a 2D projection interferogram recorded through the rotation of CCD, making the spectral resolution of Fourier-Transform spectrometer(FTS) of a limited spatial size increase by at least three times. The fringes on multi-lines were linked with the pixels of equal optical path difference (OPD). Ideally, the error of sampled phase within one pixel was less than half the wavelength, ensuring consecutive values in the over-sampled dimension while aliasing in another. In the simulation, with the calibration of 1.064μm, spectral lines at 1.31μm and 1.56μm of equal intensity were tested and observed. The result showed a bias of 0.13% at 1.31μm and 1.15% at 1.56μm in amplitude, and the FWHM at 1.31μm reduced from 25nm to 8nm after the sample points increased from 320 to 960. In the comparison of reflectance spectrum of carnauba wax within near infrared(NIR) band, the absorption peak at 1.2μm was more obvious and zoom of the band 1.38 1.43μm closer to the reference, although some fluctuation was in the short-wavelength region arousing the spectral crosstalk. In conclusion, with orthogonal shear based on the rotation of the CCD relative to the axis of WP, the spectral resolution of static FTS was enhanced by the projection of fringes to the grid coordinates and stitching the interferograms into a larger OPD, which showed the advantages of cost and miniaturization in the space-constrained NIR applications.

  15. Quantitative contrast-enhanced spectral mammography based on photon-counting detectors: A feasibility study.

    Science.gov (United States)

    Ding, Huanjun; Molloi, Sabee

    2017-08-01

    To investigate the feasibility of accurate quantification of iodine mass thickness in contrast-enhanced spectral mammography. A computer simulation model was developed to evaluate the performance of a photon-counting spectral mammography system in the application of contrast-enhanced spectral mammography. A figure-of-merit (FOM), which was defined as the decomposed iodine signal-to-noise ratio (SNR) with respect to the square root of the mean glandular dose (MGD), was chosen to optimize the imaging parameters, in terms of beam energy, splitting energy, and prefiltrations for breasts of various thicknesses and densities. Experimental phantom studies were also performed using a beam energy of 40 kVp and a splitting energy of 34 keV with 3 mm Al prefiltration. A two-step calibration method was investigated to quantify the iodine mass thickness, and was validated using phantoms composed of a mixture of glandular and adipose materials, for various breast thicknesses and densities. Finally, the traditional dual-energy log-weighted subtraction method was also studied as a comparison. The measured iodine signal from both methods was compared to the known value to characterize the quantification accuracy and precision. The optimal imaging parameters, which lead to the highest FOM, were found at a beam energy between 42 and 46 kVp with a splitting energy at 34 keV. The optimal tube voltage decreased as the breast thickness or the Al prefiltration increased. The proposed quantification method was able to measure iodine mass thickness on phantoms of various thicknesses and densities with high accuracy. The root-mean-square (RMS) error for cm-scale lesion phantoms was estimated to be 0.20 mg/cm 2 . The precision of the technique, characterized by the standard deviation of the measurements, was estimated to be 0.18 mg/cm 2 . The traditional weighted subtraction method also predicted a linear correlation between the measured signal and the known iodine mass thickness. However

  16. On the causes of spectral enhancements in solar wind power spectra

    Science.gov (United States)

    Unti, T.; Russell, C. T.

    1976-01-01

    Enhancements in power spectra of the solar-wind ion flux in the frequency neighborhood of 0.5 Hz had been noted by Unti et al. (1973). It was speculated that these were due to convected small-scale density irregularities. In this paper, 54 flux spectra calculated from OGO 5 data are examined. It is seen that the few prominent spectral peaks which occur were not generated by density irregularities, but were due to several different causes, including convected discontinuities and propagating transverse waves. A superposition of many spectra, however, reveals a moderate enhancement at a frequency corresponding to convected features with a correlation length of a proton gyroradius, consistent with the results of Neugebauer (1975).

  17. LSD enhances the emotional response to music.

    Science.gov (United States)

    Kaelen, M; Barrett, F S; Roseman, L; Lorenz, R; Family, N; Bolstridge, M; Curran, H V; Feilding, A; Nutt, D J; Carhart-Harris, R L

    2015-10-01

    There is renewed interest in the therapeutic potential of psychedelic drugs such as lysergic acid diethylamide (LSD). LSD was used extensively in the 1950s and 1960s as an adjunct in psychotherapy, reportedly enhancing emotionality. Music is an effective tool to evoke and study emotion and is considered an important element in psychedelic-assisted psychotherapy; however, the hypothesis that psychedelics enhance the emotional response to music has yet to be investigated in a modern placebo-controlled study. The present study sought to test the hypothesis that music-evoked emotions are enhanced under LSD. Ten healthy volunteers listened to five different tracks of instrumental music during each of two study days, a placebo day followed by an LSD day, separated by 5-7 days. Subjective ratings were completed after each music track and included a visual analogue scale (VAS) and the nine-item Geneva Emotional Music Scale (GEMS-9). Results demonstrated that the emotional response to music is enhanced by LSD, especially the emotions "wonder", "transcendence", "power" and "tenderness". These findings reinforce the long-held assumption that psychedelics enhance music-evoked emotion, and provide tentative and indirect support for the notion that this effect can be harnessed in the context of psychedelic-assisted psychotherapy. Further research is required to test this link directly.

  18. Development of low-dose photon-counting contrast-enhanced tomosynthesis with spectral imaging.

    Science.gov (United States)

    Schmitzberger, Florian F; Fallenberg, Eva Maria; Lawaczeck, Rüdiger; Hemmendorff, Magnus; Moa, Elin; Danielsson, Mats; Bick, Ulrich; Diekmann, Susanne; Pöllinger, Alexander; Engelken, Florian J; Diekmann, Felix

    2011-05-01

    To demonstrate the feasibility of low-dose photon-counting tomosynthesis in combination with a contrast agent (contrast material-enhanced tomographic mammography) for the differentiation of breast cancer. All studies were approved by the institutional review board, and all patients provided written informed consent. A phantom model with wells of iodinated contrast material (3 mg of iodine per milliliter) 1, 2, 5, 10, and 15 mm in diameter was assessed. Nine patients with malignant lesions and one with a high-risk lesion (atypical papilloma) were included (all women; mean age, 60.7 years). A multislit photon-counting tomosynthesis system was utilized (spectral imaging) to produce both low- and high-energy tomographic data (below and above the k edge of iodine, respectively) in a single scan, which allowed for dual-energy visualization of iodine. Images were obtained prior to contrast material administration and 120 and 480 seconds after contrast material administration. Four readers independently assessed the images along with conventional mammograms, ultrasonographic images, and magnetic resonance images. Glandular dose was estimated. Contrast agent was visible in the phantom model with simulated spherical tumor diameters as small as 5 mm. The average glandular dose was measured as 0.42 mGy per complete spectral imaging tomosynthesis scan of one breast. Because there were three time points (prior to contrast medium administration and 120 and 480 seconds after contrast medium administration), this resulted in a total dose of 1.26 mGy for the whole procedure in the breast with the abnormality. Seven of 10 cases were categorized as Breast Imaging Reporting and Data System score of 4 or higher by all four readers when reviewing spectral images in combination with mammograms. One lesion near the chest wall was not captured on the spectral image because of a positioning problem. The use of contrast-enhanced tomographic mammography has been demonstrated successfully in

  19. Artifact Interpretation of Spectral Response Measurements on Two-Terminal Multijunction Solar Cells

    NARCIS (Netherlands)

    Si, F.T.; Isabella, O.; Zeman, M.

    2016-01-01

    Multijunction solar cells promise higher power-conversion efficiency than the single-junction. With respect to two-terminal devices, an accurate measurement of the spectral response requires a delicate adjustment of the light- and voltage-biasing; otherwise it can result in artifacts in the data and

  20. Enhanced spectral domain optical coherence tomography for pathological and functional studies

    Science.gov (United States)

    Yuan, Zhijia

    Optical coherence tomography (OCT) is a novel technique that enables noninvasive or minimally invasive, cross-sectional imaging of biological tissue at sub-10mum spatial resolution and up to 2-3mm imaging depth. Numerous technological advances have emerged in recent years that have shown great potential to develop OCT into a powerful imaging and diagnostic tools. In particular, the implementation of Fourier-domain OCT (FDOCT) is a major step forward that leads to greatly improved imaging rate and image fidelity of OCT. This dissertation summarizes the work that focuses on enhancing the performances and functionalities of spectral radar based FDOCT (SDOCT) for pathological and functional applications. More specifically, chapters 1-4 emphasize on the development of SDOCT and its utility in pathological studies, including cancer diagnosis. The principle of SDOCT is first briefly outlined, followed by the design of our bench-top SDOCT systems with emphasis on spectral linear interpolation, calibration and system dispersion compensation. For ultrahigh-resolution SDOCT, time-lapse image registration and frame averaging is introduced to effectively reduce speckle noise and uncover subcellular details, showing great promise for enhancing the diagnosis of carcinoma in situ. To overcome the image depth limitation of OCT, a dual-modal imaging method combing SDOCT with high-frequency ultrasound is proposed and examined in animal cancer models to enhance the sensitivity and staging capabilities for bladder cancer diagnosis. Chapters 5-7 summarize the work on developing Doppler SDOCT for functional studies. Digital-frequency-ramping OCT (DFR-OCT) is developed in the study, which has demonstrated the ability to significantly improve the signal-to-noise ratio and thus sensitivity for retrieving subsurface blood flow imaging. New DFR algorithms and imaging processing methods are discussed to further enhance cortical CBF imaging. Applications of DFR-OCT for brain functional studies

  1. Low-Dose Contrast-Enhanced Breast CT Using Spectral Shaping Filters: An Experimental Study.

    Science.gov (United States)

    Makeev, Andrey; Glick, Stephen J

    2017-12-01

    Iodinated contrast-enhanced X-ray imaging of the breast has been studied with various modalities, including full-field digital mammography (FFDM), digital breast tomosynthesis (DBT), and dedicated breast CT. Contrast imaging with breast CT has a number of advantages over FFDM and DBT, including the lack of breast compression, and generation of fully isotropic 3-D reconstructions. Nonetheless, for breast CT to be considered as a viable tool for routine clinical use, it would be desirable to reduce radiation dose. One approach for dose reduction in breast CT is spectral shaping using X-ray filters. In this paper, two high atomic number filter materials are studied, namely, gadolinium (Gd) and erbium (Er), and compared with Al and Cu filters currently used in breast CT systems. Task-based performance is assessed by imaging a cylindrical poly(methyl methacrylate) phantom with iodine inserts on a benchtop breast CT system that emulates clinical breast CT. To evaluate detectability, a channelized hoteling observer (CHO) is used with sums of Laguerre-Gauss channels. It was observed that spectral shaping using Er and Gd filters substantially increased the dose efficiency (defined as signal-to-noise ratio of the CHO divided by mean glandular dose) as compared with kilovolt peak and filter settings used in commercial and prototype breast CT systems. These experimental phantom study results are encouraging for reducing dose of breast CT, however, further evaluation involving patients is needed.

  2. Augmenting the spectral efficiency of enhanced PAM-DMT-based optical wireless communications.

    Science.gov (United States)

    Islim, Mohamed Sufyan; Haas, Harald

    2016-05-30

    The energy efficiency of pulse-amplitude-modulated discrete multitone modulation (PAM-DMT) decreases as the modulation order of M-PAM modulation increases. Enhanced PAM-DMT (ePAM-DMT) was proposed as a solution to the reduced energy efficiency of PAM-DMT. This was achieved by allowing multiple streams of PAM-DMT to be superimposed and successively demodulated at the receiver side. In order to maintain a distortion-free unipolar ePAM-DMT system, the multiple time-domain PAM-DMT streams are required to be aligned. However, aligning the antisymmetry in ePAM-DMT is complex and results in efficiency losses. In this paper, a novel simplified method to apply the superposition modulation on M-PAM modulated discrete multitone (DMT) is introduced. Contrary to ePAM-DMT, the signal generation of the proposed system, termed augmented spectral efficiency discrete multitone (ASE-DMT), occurs in the frequency domain. This results in an improved spectral and energy efficiency. The analytical bit error rate (BER) performance bound of the proposed system is derived and compared with Monte-Carlo simulations. The system performance is shown to offer significant electrical and optical energy savings compared with ePAM-DMT and DC-biased optical orthogonal frequency division multiplexing (DCO-OFDM).

  3. Enhanced spectral emissivity of CeO{sub 2} coating with cauliflower-like microstructure

    Energy Technology Data Exchange (ETDEWEB)

    Huang Jianping [Center for Composite Materials and Structures, Harbin Institute of Technology, 150080 Harbin (China); Li Yibin, E-mail: liyibin@hit.edu.cn [Center for Composite Materials and Structures, Harbin Institute of Technology, 150080 Harbin (China); He Xiaodong; Song Guangping [Center for Composite Materials and Structures, Harbin Institute of Technology, 150080 Harbin (China); Fan Chenglei [Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, 150001 Harbin (China); Sun Yue [Center for Composite Materials and Structures, Harbin Institute of Technology, 150080 Harbin (China); Fei Weidong [School of Materials Science and Engineering, Harbin Institute of Technology, 150001 Harbin (China); Du Shanyi [Center for Composite Materials and Structures, Harbin Institute of Technology, 150080 Harbin (China)

    2012-10-15

    Highlights: Black-Right-Pointing-Pointer Cauliflower-like microstructured CeO{sub 2} coating is prepared on Ni based substrate. Black-Right-Pointing-Pointer The infrared emissive property at high temperature is investigated. Black-Right-Pointing-Pointer Rough CeO{sub 2} coating shows high emissivity, that is, 0.9 at 873 K and 0.87 at 1073 K. Black-Right-Pointing-Pointer The emissivity enhancement mechanisms for the rough CeO{sub 2} coating are discussed. - Abstract: Cerium dioxide is a transparent oxide with high refractive index (from 1.6 to 2.5 at 633 nm) in the visible and near-IR spectral regions. However, little attention has been paid to its optical property in mid-IR (2.5-25 {mu}m). Here we report that the cauliflower-like microstructured CeO{sub 2} coating deposited by electron beam physical vapor deposition technique shows high emissivity up to 0.9 at 873 K in the mid-IR spectral region. The high emissivity is attributed to the coupling between free propagating waves and space-variant polarizations caused by the cauliflower-like microstructure. This high emissivity coating shows a potential application in high temperature components.

  4. Enhanced spectral emissivity of CeO2 coating with cauliflower-like microstructure

    International Nuclear Information System (INIS)

    Huang Jianping; Li Yibin; He Xiaodong; Song Guangping; Fan Chenglei; Sun Yue; Fei Weidong; Du Shanyi

    2012-01-01

    Highlights: ► Cauliflower-like microstructured CeO 2 coating is prepared on Ni based substrate. ► The infrared emissive property at high temperature is investigated. ► Rough CeO 2 coating shows high emissivity, that is, 0.9 at 873 K and 0.87 at 1073 K. ► The emissivity enhancement mechanisms for the rough CeO 2 coating are discussed. - Abstract: Cerium dioxide is a transparent oxide with high refractive index (from 1.6 to 2.5 at 633 nm) in the visible and near-IR spectral regions. However, little attention has been paid to its optical property in mid-IR (2.5–25 μm). Here we report that the cauliflower-like microstructured CeO 2 coating deposited by electron beam physical vapor deposition technique shows high emissivity up to 0.9 at 873 K in the mid-IR spectral region. The high emissivity is attributed to the coupling between free propagating waves and space-variant polarizations caused by the cauliflower-like microstructure. This high emissivity coating shows a potential application in high temperature components.

  5. Spectral enhancement of leucocrystal violet treated footwear impression evidence in blood.

    Science.gov (United States)

    Spence, Lindsay; Asmussen, Gary

    2003-03-27

    The results presented demonstrate the capacity for spectral enhancement to substantially improve the forensic examination of footwear impressions in blood treated with leucocrystal violet (LCV). The UV-Vis absorption spectra were generated of (i) an aqueous solution of leucocrystal violet, (ii) leucocrystal violet in 3% H(2)O(2), (iii) LCV working solution and (iv) whole blood added to LCV working solution. The resultant fluorescence emission spectra were subsequently generated (lambda(ex)=630nm, lambda(em)=661-900nm). The results indicate that the UV-Vis absorption spectra of an unbuffered solution of whole blood with LCV working solution produces a strong absorbance curve with a maxima at 630nm. Subsequent excitation at this wavelength and generation of the emission spectrum in the fluorescence mode indicates that a solution of whole blood added to LCV working solution is an extremely weak fluorophore. Therefore, to enable an adequate and timely enhancement of blood impression evidence treated with LCV utilising either visible fluorescence or infrared luminescence requires (i) selection of the most appropriate excitation wavelength (lambda(ex)) and emission wavelength (lambda(em)) with extremely narrow band pass filters, which in the absence of substrate matrix interference is excitation at 630nm producing the emission maxima at 665nm and (ii) a visual enhancement system such as a CCD colour IR video camera with image integration.

  6. Spectrally resolved, broadband frequency response characterization of photodetectors using continuous-wave supercontinuum sources

    Science.gov (United States)

    Choudhury, Vishal; Prakash, Roopa; Nagarjun, K. P.; Supradeepa, V. R.

    2018-02-01

    A simple and powerful method using continuous wave supercontinuum lasers is demonstrated to perform spectrally resolved, broadband frequency response characterization of photodetectors in the NIR Band. In contrast to existing techniques, this method allows for a simple system to achieve the goal, requiring just a standard continuous wave(CW) high-power fiber laser source and an RF spectrum analyzer. From our recent work, we summarize methods to easily convert any high-power fiber laser into a CW supercontinuum. These sources in the time domain exhibit interesting properties all the way down to the femtosecond time scale. This enables measurement of broadband frequency response of photodetectors while the wide optical spectrum of the supercontinuum can be spectrally filtered to obtain this information in a spectrally resolved fashion. The method involves looking at the RF spectrum of the output of a photodetector under test when incident with the supercontinuum. By using prior knowledge of the RF spectrum of the source, the frequency response can be calculated. We utilize two techniques for calibration of the source spectrum, one using a prior measurement and the other relying on a fitted model. Here, we characterize multiple photodetectors from 150MHz bandwidth to >20GHz bandwidth at multiple bands in the NIR region. We utilize a supercontinuum source spanning over 700nm bandwidth from 1300nm to 2000nm. For spectrally resolved measurement, we utilize multiple wavelength bands such as around 1400nm and 1600nm. Interesting behavior was observed in the frequency response of the photodetectors when comparing broadband spectral excitation versus narrower band excitation.

  7. A differential spectral responsivity measurement system constructed for determining of the spectral responsivity of a single- and triple-junction photovoltaic cells

    Science.gov (United States)

    Sametoglu, Ferhat; Celikel, Oguz; Witt, Florian

    2017-10-01

    A differential spectral responsivity (DSR) measurement system has been designed and constructed at National Metrology Institute of Turkey (TUBITAK UME) to determine the spectral responsivity (SR) of a single- or a multi-junction photovoltaic device (solar cell). The DSR setup contains a broad band light bias source composed of a constructed Solar Simulator based on a 1000 W Xe-arc lamp owning a AM-1.5 filter and 250 W quartz-tungsten-halogen lamp, a designed and constructed LED-based Bias Light Sources, a DC voltage bias circuit, and a probe beam optical power tracking and correction circuit controlled with an ADuC847 microcontroller card together with an embedded C based software, designed and constructed in TUBITAK UME under this project. By using the constructed DSR measurement system, the SR calibration of solar cells, the monolitic triple-junction solar cell GaInP/GaInAs/Ge and its corresponding component cells have been performed within the EURAMET Joint Research Project SolCell.

  8. Spectral characterization of plastic scintillation detector response as a function of magnetic field strength

    Science.gov (United States)

    Simiele, E.; Kapsch, R.-P.; Ankerhold, U.; Culberson, W.; DeWerd, L.

    2018-04-01

    The purpose of this work was to characterize intensity and spectral response changes in a plastic scintillation detector (PSD) as a function of magnetic field strength. Spectra measurements as a function of magnetic field strength were performed using an optical spectrometer. The response of both a PSD and PMMA fiber were investigated to isolate the changes in response from the scintillator and the noise signal as a function of magnetic field strength. All irradiations were performed in water at a photon beam energy of 6 MV. Magnetic field strengths of (0, ±0.35, ±0.70, ±1.05, and  ±1.40) T were investigated. Four noise subtraction techniques were investigated to evaluate the impact on the resulting noise-subtracted scintillator response with magnetic field strength. The noise subtraction methods included direct spectral subtraction, the spectral method, and variants thereof. The PMMA fiber exhibited changes in response of up to 50% with magnetic field strength due to the directional light emission from \\breve{C} erenkov radiation. The PSD showed increases in response of up to 10% when not corrected for the noise signal, which agrees with previous investigations of scintillator response in magnetic fields. Decreases in the \\breve{C} erenkov light ratio with negative field strength were observed with a maximum change at  ‑1.40 T of 3.2% compared to 0 T. The change in the noise-subtracted PSD response as a function of magnetic field strength varied with the noise subtraction technique used. Even after noise subtraction, the PSD exhibited changes in response of up to 5.5% over the four noise subtraction methods investigated.

  9. Use of contrast-enhanced spectral mammography for intramammary cancer staging: preliminary results.

    Science.gov (United States)

    Blum, Katrin S; Rubbert, Christian; Mathys, Britta; Antoch, Gerald; Mohrmann, Svjetlana; Obenauer, Silvia

    2014-11-01

    To prospectively evaluate and compare the accuracy of contrast-enhanced spectral mammography (CESM) and ultrasound (US) in size measurement of breast cancer with histologic tumor sizes as gold standard. Twenty women aged between 40-73 years (mean age, 57 ± 10 years) with histologically proven invasive ductal/lobular carcinomas were included in the study. Agreement between imaging tumor size (CESM and US) and histopathologic tumor size was evaluated with Bland-Altman analysis. Stereotactically guided vacuum biopsy was performed in four patients after CESM. Two independent reviewers described artifacts of CESM. Motion artifacts did not occur in the study. CESM-specific artifacts caused by scattered radiation mostly occurred in oblique view of CESM. Background enhancement of breast tissue was seen in four patients. Mean difference of tumor sizes was 0.3 mm (6.34%) between CESM and histology and -2.2 mm (-7.59%) between US and histology. Limits of agreement ranged from -18.9 to 19.48 mm for CESM and from -17.1 to 12.7 mm with US. Especially smaller tumors with a size <23 mm were measured more precisely with CESM. Enhancement of breast tissue around microcalcifications correlated with abnormalities. CESM is accurate in size measurements of small breast tumors. On average CESM leads to a slight overestimation of tumor size, whereas US tends to underestimate tumor size. Assessment of the breast tissue can be limited by the scattered radiation artifact and background enhancement of breast tissue. CESM seems to be helpful in the characterization of breast tissue around microcalcifications. Copyright © 2014 AUR. Published by Elsevier Inc. All rights reserved.

  10. Predicting the effective response of bulk polycrystalline ferroelectric ceramics via improved spectral phase field methods

    Science.gov (United States)

    Vidyasagar, A.; Tan, W. L.; Kochmann, D. M.

    2017-09-01

    Understanding the electromechanical response of bulk polycrystalline ferroelectric ceramics requires scale-bridging approaches. Recent advances in fast numerical methods to compute the homogenized mechanical response of materials with heterogeneous microstructure have enabled the solution of hitherto intractable systems. In particular, the use of a Fourier-based spectral method as opposed to the traditional finite element method has gained significant interest in the homogenization of periodic microstructures. Here, we solve the periodic, electro-mechanically-coupled boundary value problem at the mesoscale of polycrystalline ferroelectrics in order to extract the effective response of barium titanate (BaTiO3) and lead zirconate titanate (PZT) under applied electric fields. Results include the effective electric hysteresis and the associated butterfly curve of strain vs. electric field for mean stress-free electric loading. Computational predictions of the 3D polycrystalline response show convincing agreement with our experimental electric cycling and strain hysteresis data for PZT-5A. In addition to microstructure-dependent effective physics, we also show how finite-difference-based approximations in the spectral solution scheme significantly reduce instability and ringing phenomena associated with spectral techniques and lead to spatial convergence with h-refinement, which have been major challenges when modeling high-contrast systems such as polycrystals.

  11. Enhanced embodied response following ambiguous emotional processing.

    Science.gov (United States)

    Beffara, Brice; Ouellet, Marc; Vermeulen, Nicolas; Basu, Anamitra; Morisseau, Tiffany; Mermillod, Martial

    2012-08-01

    It has generally been assumed that high-level cognitive and emotional processes are based on amodal conceptual information. In contrast, however, "embodied simulation" theory states that the perception of an emotional signal can trigger a simulation of the related state in the motor, somatosensory, and affective systems. To study the effect of social context on the mimicry effect predicted by the "embodied simulation" theory, we recorded the electromyographic (EMG) activity of participants when looking at emotional facial expressions. We observed an increase in embodied responses when the participants were exposed to a context involving social valence before seeing the emotional facial expressions. An examination of the dynamic EMG activity induced by two socially relevant emotional expressions (namely joy and anger) revealed enhanced EMG responses of the facial muscles associated with the related social prime (either positive or negative). These results are discussed within the general framework of embodiment theory.

  12. On the photosynthetic and devlopmental responses of leaves to the spectral composition of light

    OpenAIRE

    Hogewoning, S.W.

    2010-01-01

    Key words: action spectrum, artificial solar spectrum, blue light, Cucumis sativus, gas-exchange, light-emitting diodes (LEDs), light interception, light quality, non-photosynthetic pigments, photo-synthetic capacity, photomorphogenesis, photosystem excitation balance, quantum yield, red light. A wide range of plant properties respond to the spectral composition of irradiance, such as photosynthesis, photomorphogenesis, phototropism and photonastic movements. These responses affect plant pr...

  13. Contrast-enhanced spectral mammography based on a photon-counting detector: quantitative accuracy and radiation dose

    Science.gov (United States)

    Lee, Seungwan; Kang, Sooncheol; Eom, Jisoo

    2017-03-01

    Contrast-enhanced mammography has been used to demonstrate functional information about a breast tumor by injecting contrast agents. However, a conventional technique with a single exposure degrades the efficiency of tumor detection due to structure overlapping. Dual-energy techniques with energy-integrating detectors (EIDs) also cause an increase of radiation dose and an inaccuracy of material decomposition due to the limitations of EIDs. On the other hands, spectral mammography with photon-counting detectors (PCDs) is able to resolve the issues induced by the conventional technique and EIDs using their energy-discrimination capabilities. In this study, the contrast-enhanced spectral mammography based on a PCD was implemented by using a polychromatic dual-energy model, and the proposed technique was compared with the dual-energy technique with an EID in terms of quantitative accuracy and radiation dose. The results showed that the proposed technique improved the quantitative accuracy as well as reduced radiation dose comparing to the dual-energy technique with an EID. The quantitative accuracy of the contrast-enhanced spectral mammography based on a PCD was slightly improved as a function of radiation dose. Therefore, the contrast-enhanced spectral mammography based on a PCD is able to provide useful information for detecting breast tumors and improving diagnostic accuracy.

  14. Contrast-enhanced spectral mammography vs. mammography and MRI - clinical performance in a multi-reader evaluation

    NARCIS (Netherlands)

    Fallenberg, E.M.; Schmitzberger, F.F.; Amer, H.; Ingold-Heppner, B.; Balleyguier, C.; Diekmann, F.; Engelken, F.; Mann, R.M.; Renz, D.M.; Bick, U.; Hamm, B.; Dromain, C.

    2017-01-01

    OBJECTIVES: To compare the diagnostic performance of contrast-enhanced spectral mammography (CESM) to digital mammography (MG) and magnetic resonance imaging (MRI) in a prospective two-centre, multi-reader study. METHODS: One hundred seventy-eight women (mean age 53 years) with invasive breast

  15. Spectral summation and facilitation in on- and off-responses for optimized representation of communication calls in mouse inferior colliculus.

    Science.gov (United States)

    Akimov, Alexander G; Egorova, Marina A; Ehret, Günter

    2017-02-01

    Selectivity for processing of species-specific vocalizations and communication sounds has often been associated with the auditory cortex. The midbrain inferior colliculus, however, is the first center in the auditory pathways of mammals integrating acoustic information processed in separate nuclei and channels in the brainstem and, therefore, could significantly contribute to enhance the perception of species' communication sounds. Here, we used natural wriggling calls of mouse pups, which communicate need for maternal care to adult females, and further 15 synthesized sounds to test the hypothesis that neurons in the central nucleus of the inferior colliculus of adult females optimize their response rates for reproduction of the three main harmonics (formants) of wriggling calls. The results confirmed the hypothesis showing that average response rates, as recorded extracellularly from single units, were highest and spectral facilitation most effective for both onset and offset responses to the call and call models with three resolved frequencies according to critical bands in perception. In addition, the general on- and/or off-response enhancement in almost half the investigated 122 neurons favors not only perception of single calls but also of vocalization rhythm. In summary, our study provides strong evidence that critical-band resolved frequency components within a communication sound increase the probability of its perception by boosting the signal-to-noise ratio of neural response rates within the inferior colliculus for at least 20% (our criterion for facilitation). These mechanisms, including enhancement of rhythm coding, are generally favorable to processing of other animal and human vocalizations, including formants of speech sounds. © 2016 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

  16. WE-FG-207B-02: Material Reconstruction for Spectral Computed Tomography with Detector Response Function

    International Nuclear Information System (INIS)

    Liu, J; Gao, H

    2016-01-01

    Purpose: Different from the conventional computed tomography (CT), spectral CT based on energy-resolved photon-counting detectors is able to provide the unprecedented material composition. However, an important missing piece for accurate spectral CT is to incorporate the detector response function (DRF), which is distorted by factors such as pulse pileup and charge-sharing. In this work, we propose material reconstruction methods for spectral CT with DRF. Methods: The polyenergetic X-ray forward model takes the DRF into account for accurate material reconstruction. Two image reconstruction methods are proposed: a direct method based on the nonlinear data fidelity from DRF-based forward model; a linear-data-fidelity based method that relies on the spectral rebinning so that the corresponding DRF matrix is invertible. Then the image reconstruction problem is regularized with the isotropic TV term and solved by alternating direction method of multipliers. Results: The simulation results suggest that the proposed methods provided more accurate material compositions than the standard method without DRF. Moreover, the proposed method with linear data fidelity had improved reconstruction quality from the proposed method with nonlinear data fidelity. Conclusion: We have proposed material reconstruction methods for spectral CT with DRF, whichprovided more accurate material compositions than the standard methods without DRF. Moreover, the proposed method with linear data fidelity had improved reconstruction quality from the proposed method with nonlinear data fidelity. Jiulong Liu and Hao Gao were partially supported by the NSFC (#11405105), the 973 Program (#2015CB856000), and the Shanghai Pujiang Talent Program (#14PJ1404500).

  17. Simulation and Analysis of Spectral Response Function and Bandwidth of Spectrometer

    Directory of Open Access Journals (Sweden)

    Zhenyu Gao

    2016-01-01

    Full Text Available A simulation method for acquiring spectrometer’s Spectral Response Function (SRF based on Huygens Point Spread Function (PSF is suggested. Taking into account the effects of optical aberrations and diffraction, the method can obtain the fine SRF curve and corresponding spectral bandwidth at any nominal wavelength as early as in the design phase. A prism monochromator is proposed for illustrating the simulation procedure. For comparison, a geometrical ray-tracing method is also provided, with bandwidth deviations varying from 5% at 250 nm to 25% at 2400 nm. Further comparison with reported experiments shows that the areas of the SRF profiles agree to about 1%. However, the weak scattered background light on the level of 10−4 to 10−5 observed by experiment could not be covered by this simulation. This simulation method is a useful tool for forecasting the performance of an underdesigned spectrometer.

  18. Contrast-Enhanced Spectral Mammography: Comparison with Conventional Mammography and Histopathology in 152 Women

    Energy Technology Data Exchange (ETDEWEB)

    Luczyńska, Elzbieta; Heinze-Paluchowska, Sylwia; Dyczek, Sonia [Department of Radiology, Centre of Oncology, Maria Sklodowska-Curie Memorial Institute, Krakow 31-115 (Poland); Blecharz, Pawel [Department of Gynecologic Oncology, Centre of Oncology, Maria Sklodowska-Curie Memorial Institute, Krakow 31-115 (Poland); Rys, Janusz [Department of Tumour Pathology, Centre of Oncology, Maria Sklodowska-Curie Memorial Institute, Krakow 31-115 (Poland); Reinfuss, Marian [Department of Radiotherapy, Centre of Oncology, Maria Sklodowska-Curie Memorial Institute, Krakow 31-115 (Poland)

    2014-07-01

    The goal of the study was to compare conventional mammography (MG) and contrast-enhanced spectral mammography (CESM) in preoperative women. The study was approved by the local Ethics Committee and all participants provided informed consent. The study included 152 consecutive patients with 173 breast lesions diagnosed on MG or CESM. All MG examinations and consults were conducted in one oncology centre. Non-ionic contrast agent, at a total dose of 1.5 mL/kg body weight, was injected intravenous. Subsequently, CESM exams were performed with a mammography device, allowing dual-energy acquisitions. The entire procedure was done within the oncology centre. Images from low and high energy exposures were processed together and the combination provided an 'iodine' image which outlined contrast up-take in the breast. MG detected 157 lesions in 150 patients, including 92 infiltrating cancers, 12 non-infiltrating cancers, and 53 benign lesions. CESM detected 149 lesions in 128 patients, including 101 infiltrating cancers, 13 non-infiltrating cancers, and 35 benign lesions. CESM sensitivity was 100% (vs. 91% for MG), specificity was 41% (vs. 15% for MG), area under the receiver operating characteristic curve was 0.86 (vs. 0.67 for MG), and accuracy was 80% (vs. 65% for MG) for the diagnosis of breast cancer. Both MG and CESM overestimated lesion sizes compared to histopathology (p < 0.001). CESM may provide higher sensitivity for breast cancer detection and greater diagnostic accuracy than conventional mammography.

  19. Radiation exposure of contrast-enhanced spectral mammography compared with full-field digital mammography.

    Science.gov (United States)

    Jeukens, Cécile R L P N; Lalji, Ulrich C; Meijer, Eduard; Bakija, Betina; Theunissen, Robin; Wildberger, Joachim E; Lobbes, Marc B I

    2014-10-01

    Contrast-enhanced spectral mammography (CESM) shows promising initial results but comes at the cost of increased dose as compared with full-field digital mammography (FFDM). We aimed to quantitatively assess the dose increase of CESM in comparison with FFDM. Radiation exposure-related data (such as kilovoltage, compressed breast thickness, glandularity, entrance skin air kerma (ESAK), and average glandular dose (AGD) were retrieved for 47 CESM and 715 FFDM patients. All examinations were performed on 1 mammography unit. Radiation dose values reported by the unit were validated by phantom measurements. Descriptive statistics of the patient data were generated using a statistical software package. Dose values reported by the mammography unit were in good qualitative agreement with those of phantom measurements. Mean ESAK was 10.5 mGy for a CESM exposure and 7.46 mGy for an FFDM exposure. Mean AGD for a CESM exposure was 2.80 mGy and 1.55 mGy for an FFDM exposure. Compared with our institutional FFDM, the AGD of a single CESM exposure is increased by 1.25 mGy (+81%), whereas ESAK is increased by 3.07 mGy (+41%). Dose values of both techniques meet the recommendations for maximum dose in mammography.

  20. Contrast-enhanced spectral mammography: comparison with conventional mammography and histopathology in 152 women.

    Science.gov (United States)

    Luczyńska, Elzbieta; Heinze-Paluchowska, Sylwia; Dyczek, Sonia; Blecharz, Pawel; Rys, Janusz; Reinfuss, Marian

    2014-01-01

    The goal of the study was to compare conventional mammography (MG) and contrast-enhanced spectral mammography (CESM) in preoperative women. The study was approved by the local Ethics Committee and all participants provided informed consent. The study included 152 consecutive patients with 173 breast lesions diagnosed on MG or CESM. All MG examinations and consults were conducted in one oncology centre. Non-ionic contrast agent, at a total dose of 1.5 mL/kg body weight, was injected intravenous. Subsequently, CESM exams were performed with a mammography device, allowing dual-energy acquisitions. The entire procedure was done within the oncology centre. Images from low and high energy exposures were processed together and the combination provided an "iodine" image which outlined contrast up-take in the breast. MG detected 157 lesions in 150 patients, including 92 infiltrating cancers, 12 non-infiltrating cancers, and 53 benign lesions. CESM detected 149 lesions in 128 patients, including 101 infiltrating cancers, 13 non-infiltrating cancers, and 35 benign lesions. CESM sensitivity was 100% (vs. 91% for MG), specificity was 41% (vs. 15% for MG), area under the receiver operating characteristic curve was 0.86 (vs. 0.67 for MG), and accuracy was 80% (vs. 65% for MG) for the diagnosis of breast cancer. Both MG and CESM overestimated lesion sizes compared to histopathology (p mammography.

  1. Contrast-enhanced spectral mammography in patients referred from the breast cancer screening programme

    Energy Technology Data Exchange (ETDEWEB)

    Lobbes, Marc B.I.; Wildberger, Joachim E. [Maastricht University Medical Center, Department of Radiology, Maastricht (Netherlands); GROW School for Oncology and Developmental Biology, Maastricht (Netherlands); Lalji, Ulrich; Houwers, Janneke; Nijssen, Estelle C. [Maastricht University Medical Center, Department of Radiology, Maastricht (Netherlands); Nelemans, Patty J. [Maastricht University, Department of Epidemiology, Maastricht (Netherlands); Roozendaal, Lori van; Heuts, Esther [Maastricht University Medical Center, Department of Surgical Oncology, Maastricht (Netherlands); Smidt, Marjolein L. [Maastricht University Medical Center, Department of Surgical Oncology, Maastricht (Netherlands); GROW School for Oncology and Developmental Biology, Maastricht (Netherlands)

    2014-07-15

    Feasibility studies have shown that contrast-enhanced spectral mammography (CESM) increases diagnostic accuracy of mammography. We studied diagnostic accuracy of CESM in patients referred from the breast cancer screening programme, who have a lower disease prevalence than previously published papers on CESM. During 6 months, all women referred to our hospital were eligible for CESM. Two radiologists blinded to the final diagnosis provided BI-RADS classifications for conventional mammography and CESM. Statistical significance of differences between mammography and CESM was calculated using McNemar's test. Receiver operating characteristic (ROC) curves were constructed for both imaging modalities. Of the 116 eligible women, 113 underwent CESM. CESM increased sensitivity to 100.0 % (+3.1 %), specificity to 87.7 % (+45.7 %), PPV to 76.2 % (+36.5 %) and NPV to 100.0 % (+2.9 %) as compared to mammography. Differences between conventional mammography and CESM were statistically significant (p < 0.0001). A similar trend was observed in the ROC curve. For conventional mammography, AUC was 0.779. With CESM, AUC increased to 0.976 (p < 0.0001). In addition, good agreement between tumour diameters measured using CESM, breast MRI and histopathology was observed. CESM increases diagnostic performance of conventional mammography, even in lower prevalence patient populations such as referrals from breast cancer screening. (orig.)

  2. Si-strip photon counting detectors for contrast-enhanced spectral mammography

    Science.gov (United States)

    Chen, Buxin; Reiser, Ingrid; Wessel, Jan C.; Malakhov, Nail; Wawrzyniak, Gregor; Hartsough, Neal E.; Gandhi, Thulasi; Chen, Chin-Tu; Iwanczyk, Jan S.; Barber, William C.

    2015-08-01

    We report on the development of silicon strip detectors for energy-resolved clinical mammography. Typically, X-ray integrating detectors based on scintillating cesium iodide CsI(Tl) or amorphous selenium (a-Se) are used in most commercial systems. Recently, mammography instrumentation has been introduced based on photon counting Si strip detectors. The required performance for mammography in terms of the output count rate, spatial resolution, and dynamic range must be obtained with sufficient field of view for the application, thus requiring the tiling of pixel arrays and particular scanning techniques. Room temperature Si strip detector, operating as direct conversion x-ray sensors, can provide the required speed when connected to application specific integrated circuits (ASICs) operating at fast peaking times with multiple fixed thresholds per pixel, provided that the sensors are designed for rapid signal formation across the X-ray energy ranges of the application. We present our methods and results from the optimization of Si-strip detectors for contrast enhanced spectral mammography. We describe the method being developed for quantifying iodine contrast using the energy-resolved detector with fixed thresholds. We demonstrate the feasibility of the method by scanning an iodine phantom with clinically relevant contrast levels.

  3. Factors affecting the precision of lesion sizing with contrast-enhanced spectral mammography.

    Science.gov (United States)

    Travieso-Aja, M Del Mar; Naranjo-Santana, P; Fernández-Ruiz, C; Severino-Rondón, W; Maldonado-Saluzzi, D; Rodríguez Rodríguez, M; Vega-Benítez, V; Luzardo, O P

    2018-03-01

    To evaluate the precision of the pre-surgical measurement of the size of breast cancer by contrast-enhanced spectral mammography (CESM). This was a retrospective study of 204 breast cancers. Variables related to tumour biology and anthropometric variables were recorded and considered when evaluating the efficacy of CESM in predicting tumour size. Microscopic measurement of the largest diameter of the tumour at pathology was chosen as the reference standard. The mean size of tumours at pathology was 20.7±15.8 mm, while at CESM it was 23.6±16.7 mm (Bland-Altman 2.9 mm overestimation, 2.9 mm; 95% confidence interval [CI]: -10.3-16.2 mm). Spearman's correlation coefficient was 0.83 (p<0.0001). The concordance analysis indicated that 37.8% of the measurements were concordant, 47% were overestimated, and 15.2% were underestimated. Tumour size, nodal involvement, breast density, and breast size significantly modified the sizing accuracy. Quality of tumour size prediction with CESM is good, and this appears to be a promising imaging technique in the surgical planning of breast cancer. Biological tumour features, and anthropological characteristics of the patients do, however, affect the diagnostic precision and should be taken into account. Copyright © 2017 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

  4. Contrast-enhanced spectral mammography improves diagnostic accuracy in the symptomatic setting.

    Science.gov (United States)

    Tennant, S L; James, J J; Cornford, E J; Chen, Y; Burrell, H C; Hamilton, L J; Girio-Fragkoulakis, C

    2016-11-01

    To assess the diagnostic accuracy of contrast-enhanced spectral mammography (CESM), and gauge its "added value" in the symptomatic setting. A retrospective multi-reader review of 100 consecutive CESM examinations was performed. Anonymised low-energy (LE) images were reviewed and given a score for malignancy. At least 3 weeks later, the entire examination (LE and recombined images) was reviewed. Histopathology data were obtained for all cases. Differences in performance were assessed using receiver operator characteristic (ROC) analysis. Sensitivity, specificity, and lesion size (versus MRI or histopathology) differences were calculated. Seventy-three percent of cases were malignant at final histology, 27% were benign following standard triple assessment. ROC analysis showed improved overall performance of CESM over LE alone, with area under the curve of 0.93 versus 0.83 (p<0.025). CESM showed increased sensitivity (95% versus 84%, p<0.025) and specificity (81% versus 63%, p<0.025) compared to LE alone, with all five readers showing improved accuracy. Tumour size estimation at CESM was significantly more accurate than LE alone, the latter tending to undersize lesions. In 75% of cases, CESM was deemed a useful or significant aid to diagnosis. CESM provides immediately available, clinically useful information in the symptomatic clinic in patients with suspicious palpable abnormalities. Radiologist sensitivity, specificity, and size accuracy for breast cancer detection and staging are all improved using CESM as the primary mammographic investigation. Copyright © 2016 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

  5. Contrast-enhanced spectral mammography in patients referred from the breast cancer screening programme.

    Science.gov (United States)

    Lobbes, Marc B I; Lalji, Ulrich; Houwers, Janneke; Nijssen, Estelle C; Nelemans, Patty J; van Roozendaal, Lori; Smidt, Marjolein L; Heuts, Esther; Wildberger, Joachim E

    2014-07-01

    Feasibility studies have shown that contrast-enhanced spectral mammography (CESM) increases diagnostic accuracy of mammography. We studied diagnostic accuracy of CESM in patients referred from the breast cancer screening programme, who have a lower disease prevalence than previously published papers on CESM. During 6 months, all women referred to our hospital were eligible for CESM. Two radiologists blinded to the final diagnosis provided BI-RADS classifications for conventional mammography and CESM. Statistical significance of differences between mammography and CESM was calculated using McNemar's test. Receiver operating characteristic (ROC) curves were constructed for both imaging modalities. Of the 116 eligible women, 113 underwent CESM. CESM increased sensitivity to 100.0% (+3.1%), specificity to 87.7% (+45.7%), PPV to 76.2% (+36.5%) and NPV to 100.0% (+2.9%) as compared to mammography. Differences between conventional mammography and CESM were statistically significant (p mammography, AUC was 0.779. With CESM, AUC increased to 0.976 (p mammography, even in lower prevalence patient populations such as referrals from breast cancer screening. • CESM is feasible in the workflow of referrals from routine breast screening. • CESM is superior to mammography, even in low disease prevalence populations. • CESM has an extremely high negative predictive value for breast cancer. • CESM is comparable to MRI in assessment of breast cancer extent. • CESM is comparable to histopathology in assessment of breast cancer extent.

  6. Optimization of contrast-enhanced spectral mammography depending on clinical indication.

    Science.gov (United States)

    Dromain, Clarisse; Canale, Sandra; Saab-Puong, Sylvie; Carton, Ann-Katherine; Muller, Serge; Fallenberg, Eva Maria

    2014-10-01

    The objective is to optimize low-energy (LE) and high-energy (HE) exposure parameters of contrast-enhanced spectral mammography (CESM) examinations in four different clinical applications for which different levels of average glandular dose (AGD) and ratios between LE and total doses are required. The optimization was performed on a Senographe DS with a SenoBright® upgrade. Simulations were performed to find the optima by maximizing the contrast-to-noise ratio (CNR) on the recombined CESM image using different targeted doses and LE image quality. The linearity between iodine concentration and CNR as well as the minimal detectable iodine concentration was assessed. The image quality of the LE image was assessed on the CDMAM contrast-detail phantom. Experiments confirmed the optima found on simulation. The CNR was higher for each clinical indication than for SenoBright®, including the screening indication for which the total AGD was 22% lower. Minimal iodine concentrations detectable in the case of a 3-mm-diameter round tumor were 12.5% lower than those obtained for the same dose in the clinical routine. LE image quality satisfied EUREF acceptable limits for threshold contrast. This newly optimized set of acquisition parameters allows increased contrast detectability compared to parameters currently used without a significant loss in LE image quality.

  7. Added Value of Contrast-Enhanced Spectral Mammography in Postscreening Assessment.

    Science.gov (United States)

    Tardivel, Anne-Marie; Balleyguier, Corinne; Dunant, Ariane; Delaloge, Suzette; Mazouni, Chafika; Mathieu, Marie-Christine; Dromain, Clarisse

    2016-09-01

    To assess the value on diagnostic and treatment management of contrast-enhanced spectral mammography (CESM), as adjunct to mammography (MG) and ultrasound (US) in postscreening in a breast cancer unit for patients with newly diagnosed breast cancer or with suspicious findings on conventional imaging. Retrospective review of routine use of bilateral CESM performed between September 2012 and September 2013 in 195 women with suspicious or undetermined findings on MG and/or US. CESM images were blindly reviewed by two radiologists for BI-RADS(®) assessment and probability of malignancy. Each lesion was definitely confirmed either with histopathology or follow-up. Two hundred and ninety-nine lesions were detected (221 malignant). CESM sensitivity, specificity, positive-predictive value and negative-predictive value were 94% (CI: 89-96%), 74% (CI: 63-83%), 91% (CI: 86-94%) and 81% (CI: 70-89%), respectively, with 18 false positive and 14 false negative. CESM changed diagnostic and treatment strategy in 41 (21%) patients either after detection of additional malignant lesions in 38 patients (19%)-with a more extensive surgery (n = 21) or neo-adjuvant chemotherapy (n = 1)-or avoiding further biopsy for 20 patients with negative CESM. CESM can be performed easily in a clinical assessment after positive breast cancer screening and may change significantly the diagnostic and treatment strategy through breast cancer staging. © 2016 Wiley Periodicals, Inc.

  8. Performance optimization of spectral amplitude coding OCDMA system using new enhanced multi diagonal code

    Science.gov (United States)

    Imtiaz, Waqas A.; Ilyas, M.; Khan, Yousaf

    2016-11-01

    This paper propose a new code to optimize the performance of spectral amplitude coding-optical code division multiple access (SAC-OCDMA) system. The unique two-matrix structure of the proposed enhanced multi diagonal (EMD) code and effective correlation properties, between intended and interfering subscribers, significantly elevates the performance of SAC-OCDMA system by negating multiple access interference (MAI) and associated phase induce intensity noise (PIIN). Performance of SAC-OCDMA system based on the proposed code is thoroughly analyzed for two detection techniques through analytic and simulation analysis by referring to bit error rate (BER), signal to noise ratio (SNR) and eye patterns at the receiving end. It is shown that EMD code while using SDD technique provides high transmission capacity, reduces the receiver complexity, and provides better performance as compared to complementary subtraction detection (CSD) technique. Furthermore, analysis shows that, for a minimum acceptable BER of 10-9 , the proposed system supports 64 subscribers at data rates of up to 2 Gbps for both up-down link transmission.

  9. Contrast-enhanced spectral mammography in patients referred from the breast cancer screening programme

    International Nuclear Information System (INIS)

    Lobbes, Marc B.I.; Wildberger, Joachim E.; Lalji, Ulrich; Houwers, Janneke; Nijssen, Estelle C.; Nelemans, Patty J.; Roozendaal, Lori van; Heuts, Esther; Smidt, Marjolein L.

    2014-01-01

    Feasibility studies have shown that contrast-enhanced spectral mammography (CESM) increases diagnostic accuracy of mammography. We studied diagnostic accuracy of CESM in patients referred from the breast cancer screening programme, who have a lower disease prevalence than previously published papers on CESM. During 6 months, all women referred to our hospital were eligible for CESM. Two radiologists blinded to the final diagnosis provided BI-RADS classifications for conventional mammography and CESM. Statistical significance of differences between mammography and CESM was calculated using McNemar's test. Receiver operating characteristic (ROC) curves were constructed for both imaging modalities. Of the 116 eligible women, 113 underwent CESM. CESM increased sensitivity to 100.0 % (+3.1 %), specificity to 87.7 % (+45.7 %), PPV to 76.2 % (+36.5 %) and NPV to 100.0 % (+2.9 %) as compared to mammography. Differences between conventional mammography and CESM were statistically significant (p < 0.0001). A similar trend was observed in the ROC curve. For conventional mammography, AUC was 0.779. With CESM, AUC increased to 0.976 (p < 0.0001). In addition, good agreement between tumour diameters measured using CESM, breast MRI and histopathology was observed. CESM increases diagnostic performance of conventional mammography, even in lower prevalence patient populations such as referrals from breast cancer screening. (orig.)

  10. Contrast-Enhanced Spectral Mammography: Comparison with Conventional Mammography and Histopathology in 152 Women

    International Nuclear Information System (INIS)

    Luczyńska, Elzbieta; Heinze-Paluchowska, Sylwia; Dyczek, Sonia; Blecharz, Pawel; Rys, Janusz; Reinfuss, Marian

    2014-01-01

    The goal of the study was to compare conventional mammography (MG) and contrast-enhanced spectral mammography (CESM) in preoperative women. The study was approved by the local Ethics Committee and all participants provided informed consent. The study included 152 consecutive patients with 173 breast lesions diagnosed on MG or CESM. All MG examinations and consults were conducted in one oncology centre. Non-ionic contrast agent, at a total dose of 1.5 mL/kg body weight, was injected intravenous. Subsequently, CESM exams were performed with a mammography device, allowing dual-energy acquisitions. The entire procedure was done within the oncology centre. Images from low and high energy exposures were processed together and the combination provided an 'iodine' image which outlined contrast up-take in the breast. MG detected 157 lesions in 150 patients, including 92 infiltrating cancers, 12 non-infiltrating cancers, and 53 benign lesions. CESM detected 149 lesions in 128 patients, including 101 infiltrating cancers, 13 non-infiltrating cancers, and 35 benign lesions. CESM sensitivity was 100% (vs. 91% for MG), specificity was 41% (vs. 15% for MG), area under the receiver operating characteristic curve was 0.86 (vs. 0.67 for MG), and accuracy was 80% (vs. 65% for MG) for the diagnosis of breast cancer. Both MG and CESM overestimated lesion sizes compared to histopathology (p < 0.001). CESM may provide higher sensitivity for breast cancer detection and greater diagnostic accuracy than conventional mammography

  11. Experimental and theoretical studies of spectral alteration in ultrasonic waves resulting from nonlinear elastic response in rock

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, P.A.; McCall, K.R.; Meegan, G.D. Jr. [Los Alamos National Lab., NM (United States)

    1993-11-01

    Experiments in rock show a large nonlinear elastic wave response, far greater than that of gases, liquids and most other solids. The large response is attributed to structural defects in rock including microcracks and grain boundaries. In the earth, a large nonlinear response may be responsible for significant spectral alteration at amplitudes and distances currently considered to be well within the linear elastic regime.

  12. Experimental and theoretical studies of spectral alteration in ultrasonic waves resulting from nonlinear elastic response in rock

    International Nuclear Information System (INIS)

    Johnson, P.A.; McCall, K.R.; Meegan, G.D. Jr.

    1993-01-01

    Experiments in rock show a large nonlinear elastic wave response, far greater than that of gases, liquids and most other solids. The large response is attributed to structural defects in rock including microcracks and grain boundaries. In the earth, a large nonlinear response may be responsible for significant spectral alteration at amplitudes and distances currently considered to be well within the linear elastic regime

  13. Broad spectral response photodetector based on individual tin-doped CdS nanowire

    Directory of Open Access Journals (Sweden)

    Weichang Zhou

    2014-12-01

    Full Text Available High purity and tin-doped 1D CdS micro/nano-structures were synthesized by a convenient thermal evaporation method. SEM, EDS, XRD and TEM were used to examine the morphology, composition, phase structure and crystallinity of as-prepared samples. Raman spectrum was used to confirm tin doped into CdS effectively. The effect of impurity on the photoresponse properties of photodetectors made from these as-prepared pure and tin-doped CdS micro/nano-structures under excitation of light with different wavelength was investigated. Various photoconductive parameters such as responsivity, external quantum efficiency, response time and stability were analyzed to evaluate the advantage of doped nanowires and the feasibility for photodetector application. Comparison with pure CdS nanobelt, the tin-doped CdS nanowires response to broader spectral range while keep the excellect photoconductive parameters. Both trapped state induced by tin impurity and optical whispering gallery mode microcavity effect in the doped CdS nanowires contribute to the broader spectral response. The micro-photoluminescence was used to confirm the whispering gallery mode effect and deep trapped state in the doped CdS nanowires.

  14. Modeling Climate Responses to Spectral Solar Forcing on Centennial and Decadal Time Scales

    Science.gov (United States)

    Wen, G.; Cahalan, R.; Rind, D.; Jonas, J.; Pilewskie, P.; Harder, J.

    2012-01-01

    We report a series of experiments to explore clima responses to two types of solar spectral forcing on decadal and centennial time scales - one based on prior reconstructions, and another implied by recent observations from the SORCE (Solar Radiation and Climate Experiment) SIM (Spectral 1rradiance Monitor). We apply these forcings to the Goddard Institute for Space Studies (GISS) Global/Middle Atmosphere Model (GCMAM). that couples atmosphere with ocean, and has a model top near the mesopause, allowing us to examine the full response to the two solar forcing scenarios. We show different climate responses to the two solar forCing scenarios on decadal time scales and also trends on centennial time scales. Differences between solar maximum and solar minimum conditions are highlighted, including impacts of the time lagged reSponse of the lower atmosphere and ocean. This contrasts with studies that assume separate equilibrium conditions at solar maximum and minimum. We discuss model feedback mechanisms involved in the solar forced climate variations.

  15. The effect of spectral filters on VEP and alpha-wave responses.

    Science.gov (United States)

    Willeford, Kevin T; Fimreite, Vanessa; Ciuffreda, Kenneth J

    2016-01-01

    Spectral filters are used to treat light sensitivity in individuals with traumatic brain injury (TBI); however, the effect of these filters on normal visual function has not been elucidated. Thus, the current study aimed to determine the effect of spectral filters on objectively-measured visual-evoked potential (VEP) and alpha-wave responses in the visually-normal population. The full-field (15°H×17°V), pattern-reversal VEP (20' check size, mean luminance 52cd/m(2)) was administered to 20 visually-normal individuals. They were tested with four Intuitive-Colorimeter-derived, broad-band, spectral filters (i.e., gray/neutral density, blue, yellow, and red), which produced similar luminance values for the test stimulus. The VEP N75 and P100 latencies, and VEP amplitude, were recorded. Power spectrum analysis was used to derive the respective powers at each frequency, and peak frequency, for the selected 9-11Hz components of the alpha band. Both N75 and P100 latencies increased with the addition of each filter when compared to baseline. Additionally, each filter numerically reduced intra-session amplitude variability relative to baseline. There were no significant effects on either the mean VEP amplitude or alpha wave parameters. The Intuitive Colorimeter filters significantly increased both N75 and P100 latencies, an effect which is primarily attributable (∼75%) to luminance, and in some cases, specific spectral effects (e.g., blue and red). VEP amplitude and alpha power were not significantly affected. These findings provide an important reference to which either amplitude or power changes in light-sensitive, younger clinical groups can be compared. Copyright © 2015 Spanish General Council of Optometry. Published by Elsevier Espana. All rights reserved.

  16. The Covalent Binding of Photosensitive Dyes to Monocrystalline Silicon Surface and Their Spectral Response

    Institute of Scientific and Technical Information of China (English)

    郭志新; 郝纪祥; 张祖训; 曹子祥

    1993-01-01

    A chemical method is proposed to bond photo-sensitive dyes directly to the surface of polished monocrystalline silicon. A methincyanine dye and a trimethincyanine dye have been bonded covalently onto silicon surface through Si—N bond, which are characterized by XPS technique and laser Raman spectra. Photovoltaic effect has been observed with the In/dye/n-Si sandwich devices composed of the dye-bonded n-Si wafers. Significant spectral response shows the characteristic absorptance maxima of the bonded dyes.

  17. Spectral-Amplitude-Coded OCDMA Optimized for a Realistic FBG Frequency Response

    Science.gov (United States)

    Penon, Julien; El-Sahn, Ziad A.; Rusch, Leslie A.; Larochelle, Sophie

    2007-05-01

    We develop a methodology for numerical optimization of fiber Bragg grating frequency response to maximize the achievable capacity of a spectral-amplitude-coded optical code-division multiple-access (SAC-OCDMA) system. The optimal encoders are realized, and we experimentally demonstrate an incoherent SAC-OCDMA system with seven simultaneous users. We report a bit error rate (BER) of 2.7 x 10-8 at 622 Mb/s for a fully loaded network (seven users) using a 9.6-nm optical band. We achieve error-free transmission (BER < 1 x 10-9) for up to five simultaneous users.

  18. Enhancement of Immune Memory Responses to Respiratory Infection

    Science.gov (United States)

    2017-08-01

    AWARD NUMBER: W81XWH-16-1-0360 TITLE: Enhancement of Immune Memory Responses to Respiratory Infection PRINCIPAL INVESTIGATORs: Dr Min Chen PhD...5a. CONTRACT NUMBER Enhancement of Immune Memory Responses to Respiratory Infection 5b. GRANT NUMBER W81XWH-16-1-0360 5c. PROGRAM ELEMENT NUMBER...entitled “ENHANCEMENT OF IMMUNE MEMORY RESPONSES TO RESPIRATORY INFECTION: AUTOPHAGY IN MEMORY B-CELLS RESPONSE TO INFLUENZA VACCINE (AMBRIV

  19. Computer-aided diagnosis of contrast-enhanced spectral mammography: A feasibility study.

    Science.gov (United States)

    Patel, Bhavika K; Ranjbar, Sara; Wu, Teresa; Pockaj, Barbara A; Li, Jing; Zhang, Nan; Lobbes, Mark; Zhang, Bin; Mitchell, J Ross

    2018-01-01

    To evaluate whether the use of a computer-aided diagnosis-contrast-enhanced spectral mammography (CAD-CESM) tool can further increase the diagnostic performance of CESM compared with that of experienced radiologists. This IRB-approved retrospective study analyzed 50 lesions described on CESM from August 2014 to December 2015. Histopathologic analyses, used as the criterion standard, revealed 24 benign and 26 malignant lesions. An expert breast radiologist manually outlined lesion boundaries on the different views. A set of morphologic and textural features were then extracted from the low-energy and recombined images. Machine-learning algorithms with feature selection were used along with statistical analysis to reduce, select, and combine features. Selected features were then used to construct a predictive model using a support vector machine (SVM) classification method in a leave-one-out-cross-validation approach. The classification performance was compared against the diagnostic predictions of 2 breast radiologists with access to the same CESM cases. Based on the SVM classification, CAD-CESM correctly identified 45 of 50 lesions in the cohort, resulting in an overall accuracy of 90%. The detection rate for the malignant group was 88% (3 false-negative cases) and 92% for the benign group (2 false-positive cases). Compared with the model, radiologist 1 had an overall accuracy of 78% and a detection rate of 92% (2 false-negative cases) for the malignant group and 62% (10 false-positive cases) for the benign group. Radiologist 2 had an overall accuracy of 86% and a detection rate of 100% for the malignant group and 71% (8 false-positive cases) for the benign group. The results of our feasibility study suggest that a CAD-CESM tool can provide complementary information to radiologists, mainly by reducing the number of false-positive findings. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Present and future status of flexible spectral imaging color enhancement and blue laser imaging technology.

    Science.gov (United States)

    Osawa, Hiroyuki; Yamamoto, Hironori

    2014-01-01

    The usefulness of flexible spectral imaging color enhancement (FICE) has been reported for evaluating the esophagus, stomach, and small and large intestine. Higher contrast is shown between cancer and the surrounding mucosa in the esophagus and stomach and may facilitate the detection of gastric cancers missed by white light imaging alone. The surface patterns of gastric mucosa are clearly visualized in non-malignant areas but are irregular and blurred in malignant areas, leading to clear demarcation. Capsule endoscopy with FICE detects angiodysplasia and erosions of the small intestine. The surface and vascular pattern with FICE is useful for the differential diagnosis of colorectal polyps. However, FICE remains somewhat poor at visualizing mucosal microvasculature on a tumor surface. Narrow-band imaging (NBI) is dark in observing whole gastric mucosa and poor at visualizing mucosal microstructure. Blue laser imaging (BLI) has the potential to resolve these limitations. Narrow-band laser light combined with white light shows irregular microvessels on both differentiated and undifferentiated gastric cancer similar to those using NBI. In addition, irregular surface patterns including minute white zones are clearly seen on the uneven surface of differentiated lesions, resulting in exclusion of undifferentiated lesions. Using both distant and close-up views, a high contrast between green intestinal metaplasia and brown gastric cancer may lead to early detection of gastric cancers and determination of a demarcation line. BLI produces high-contrast images in esophageal cancer with clear vision of intrapapillary capillary loops and also predicts the histopathological diagnosis and depth of invasion in colorectal neoplasms. © 2013 The Authors. Digestive Endoscopy © 2013 Japan Gastroenterological Endoscopy Society.

  1. Spectral Induced Polarization (SIP) monitoring during Microbial Enhanced Oil Recovery (MEOR)

    Science.gov (United States)

    Heenan, J. W.; Ntarlagiannis, D.; Slater, L. D.

    2010-12-01

    Jeffrey Heenan, Dimitrios Ntarlagiannis, Lee Slater Department of Earth and Environmental Sciences, Rutgers University, Newark NJ Microbial Enhanced Oil Recovery (MEOR) is an established, cost effective, method for enhancing tertiary oil recovery. Although not commonly used for shallow heavy oils, it could be a viable alternative since it can offer sustainable economic recovery and minimal environmental impact. A critical component of successful MEOR treatments is accurate, real time monitoring of the biodegradation processes resulting from the injection of microbial communities into the formation; results of recent biogeophysical research suggest that minimally-invasive geophysical methods could significantly contribute to such monitoring efforts. Here we present results of laboratory experiments, to assess the sensitivity of the spectral induced polarization method (SIP) to MEOR treatments. We used heavy oil, obtained from a shallow oilfield in SW Missouri, to saturate three sand columns. We then followed common industry procedures,and used a commercially available microbial consortia, to treat the oil columns. The active MEOR experiments were performed in duplicate while a control column maintained similar conditions, without promoting microbial activity and oil degradation. We monitored the SIP signatures, between 0.001 Hz and 1000 Hz, for a period of six months. To support the geophysical measurements we also monitored common geochemical parameters, including pH, Eh and fluid conductivity, and collected weekly fluid samples from the outflow and inflow for further analysis; fluid samples were analyzed to confirm that microbes actively degraded the heavy oils in the column while destructive analysis of the solid materials was performed upon termination of the experiment. Preliminary analysis of the results suggests that SIP is sensitive to MEOR processes. In both inoculated columns we recorded an increase in the low frequency polarization with time; measureable

  2. Contrast-Enhanced Spectral Mammography is Comparable to MRI in the Assessment of Residual Breast Cancer Following Neoadjuvant Systemic Therapy.

    Science.gov (United States)

    Patel, Bhavika K; Hilal, Talal; Covington, Matthew; Zhang, Nan; Kosiorek, Heidi E; Lobbes, Marc; Northfelt, Donald W; Pockaj, Barbara A

    2018-05-01

    To evaluate the performance of contrast-enhanced spectral mammography (CESM) compared to MRI in the assessment of tumor response in breast cancer patients undergoing neoadjuvant systemic therapy (NST). The institutional review board approved this study. From September 2014 to June 2017, we identified patients with pathologically confirmed invasive breast cancer who underwent NST. All patients had both CESM and MRI performed pre- and post-NST with pathological assessment after surgical management. Size of residual malignancy on post-NST CESM and MRI was compared with surgical pathology. Lin concordance and Pearson correlation coefficient were used to assess agreement. Bland-Altman plots were used to visualize the differences between tumor size on imaging and pathology. Sixty-five patients were identified. Mean age was 52.7 (range 30-76) years. Type of NST included chemotherapy in 53 (82%) and endocrine therapy in 12 (18%). Mean tumor size after NST was 14.6 (range 0-105) mm for CESM and 14.2 mm (range 0-75 mm) for MRI compared with 19.6 (range 0-100) mm on final surgical pathology. Equivalence tests demonstrated that mean tumor size measured by CESM (p = 0.009) or by MRI (p = 0.01) was equivalent to the mean tumor size measured by pathology within - 1 and 1-cm range. Comparing CESM versus MRI for assessment of complete response, the sensitivity was 95% versus 95%, specificity 66.7% versus 68.9%, positive predictive value 55.9% versus 57.6%, and negative predictive value 96.7% versus 96.9% respectively. CESM was comparable to MRI in assessing residual malignancy after completion of NST.

  3. The spectral response of Buxus sempervirens to different types of environmental stress - A laboratory experiment

    Science.gov (United States)

    de Jong, Steven M.; Addink, Elisabeth A.; Hoogenboom, Priscilla; Nijland, Wiebe

    2012-11-01

    The European Mediterranean regions are expected to encounter drier summer conditions and warmer temperatures for the winter of +2 °C and of +5 °C for the summer in the next six decennia. As a result the natural vegetation will face harsher conditions due to lower water availability, longer summer droughts and higher temperatures resulting in plant stress conditions. To monitor vegetation conditions like stress and leaf area index dynamics in our study area in Mediterranean France we use earth observation techniques like imaging spectroscopy. To assist image analysis interpretation we carried out a laboratory experiment to investigate the spectral and visible response of Buxus sempervirens, a common Mediterranean species, to five different types of stress: drought, drought-and-heat, light deprivation, total saturation and chlorine poisoning. For 52 days plants were subjected to stress. We collected data on the visible and spectral signs, and calculated thirteen vegetation indices. The plant's response time to different stress types varied from 10 to 32 days. Spectroscopic techniques revealed plant stress up to 15 days earlier than visual inspection. Visible signs of stress of the plants included curling and shrinking of the leaves, de-colouring of the leaves, leaves becoming breakable, opening up of the plant's canopy and sagging of the branches. Spectral signs of stress occurred first in the water absorption bands at 1450 and 1940 nm, followed by reduced absorption in the visible wavelengths, and next by reduced reflectance in near infrared. Light deprivation did not result in any stress signs, while drought, drought and heat and chlorine poisoning resulted in significant stress. The spectral response did not show differences for different stress types. Analysis of the vegetation indices identified the Carter-2 (R695/R760), the Red-Green Index (R690/R550) and the Vogelman-2 (R734 - R747)/(R715 + R726) as the best performing ones to identify stress. The lab

  4. PILOT STUDY: Report on the CCPR Pilot Comparison: Spectral Responsivity 10 nm to 20 nm

    Science.gov (United States)

    Scholze, Frank; Vest, Robert; Saito, Terubumi

    2010-01-01

    The CCPR Pilot Comparison on spectral responsivity in the 10 nm to 20 nm spectral range was carried out within the framework of the CIPM Mutual Recognition Arrangement by three laboratories: PTB (Germany), NIST (USA), and NMIJ/AIST (Japan) with PTB acting as the central and reporting laboratory. All participating laboratories used monochromatized synchrotron radiation. PTB and NIST used a cryogenic radiometer as the primary standard detector and NMIJ, an ionization chamber with extrapolation by a wavelength-independent detector. The aim of the pilot comparison was to check the accuracy of the radiometric scale of spectral responsivity in the short wavelength EUV spectral range which has recently gained in technological importance. The wavelengths of measurement were from 11.5 nm to 20 nm in 0.5 nm steps and additionally 12.2 nm. The comparison was carried out through the calibration of a group of transfer standard detectors. Two sets of three diodes of types AXUV and SXUV from International Radiation Detectors, Inc. were used for the comparison. The comparison had the form of a star comparison: Pilot-lab A-pilot-lab B-pilot, PTB acting as the pilot laboratory. All results were communicated directly to the pilot laboratory. The report describes in detail the measurements made at PTB and summarizes the reports submitted by the participants. Measurements carried out by the pilot laboratory before and after the circulation of the detectors proved that the stability of the detectors was sufficient for the comparison. For the type AXUV detectors, however, changes in their responsivity contributed to the uncertainty of the comparison. Measurement results from participants and their associated uncertainties were analyzed in this report according to the Guidelines for CCPR Comparison Report Preparation. The uncertainty contributions were separated, as to whether they are wavelength dependent or not. All bilateral DoE are well within the respective k = 2 expanded uncertainty

  5. Interactions among spectral components of radiation in the growth responses of rice, tomato and strawberry

    International Nuclear Information System (INIS)

    Inada, K.; Matsuno, A.

    1985-01-01

    Effects of spectral components and their ratios of radiation on simultaneous growth responses were investigated with rice, tomato and strawberry plants exposed to lights with a high fluence rate (350 or 408 μmol m -2 s -1 , 400-700 nm) during every daytime. Both elongation growth and Ieaf area development in rice and strawberry were promoted by red (R) but inhibited by blue (B) component depending on the each fluence rate. However, leaf area in tomato responded in opposite direction to these. The elongation growth was remarkably increased with the fluence rate of far-red (FR) in tomato and strawberry, but not in rice. These responses were lineary increased, except FR and UV effects, with logarithmic R/B ratio in rice and strawberry but not in tomato. A very low R/FR ratio caused a strong promotion of both elongation and leaf area in tomato, while it promoted petiole elengation but inhibited leaf area development in strawberry. The elongation and leaf area development responded to R/FR in reverse way between rice and strawberry. Chlorophyll content of leaves was generally decreased with the increase of logarithmic R/B ratio in all the species. Areal weight of leaf and dry weight increment/leaf area were more or less increased with R/B and R/ FR ratios, Dry weight increment varied with the spectral ratios in almost the same way as leaf area, suggesting that spectral dependence of photosynthetic production was not much different between the species. Some discussions were made on the photoreceptor pigments involved in the elongation growth and leaf area development, and on the selection of light quantity to ensure a normal growth of each plant species

  6. Rayleigh radiance computations for satellite remote sensing: accounting for the effect of sensor spectral response function.

    Science.gov (United States)

    Wang, Menghua

    2016-05-30

    To understand and assess the effect of the sensor spectral response function (SRF) on the accuracy of the top of the atmosphere (TOA) Rayleigh-scattering radiance computation, new TOA Rayleigh radiance lookup tables (LUTs) over global oceans and inland waters have been generated. The new Rayleigh LUTs include spectral coverage of 335-2555 nm, all possible solar-sensor geometries, and surface wind speeds of 0-30 m/s. Using the new Rayleigh LUTs, the sensor SRF effect on the accuracy of the TOA Rayleigh radiance computation has been evaluated for spectral bands of the Visible Infrared Imaging Radiometer Suite (VIIRS) on the Suomi National Polar-orbiting Partnership (SNPP) satellite and the Joint Polar Satellite System (JPSS)-1, showing some important uncertainties for VIIRS-SNPP particularly for large solar- and/or sensor-zenith angles as well as for large Rayleigh optical thicknesses (i.e., short wavelengths) and bands with broad spectral bandwidths. To accurately account for the sensor SRF effect, a new correction algorithm has been developed for VIIRS spectral bands, which improves the TOA Rayleigh radiance accuracy to ~0.01% even for the large solar-zenith angles of 70°-80°, compared with the error of ~0.7% without applying the correction for the VIIRS-SNPP 410 nm band. The same methodology that accounts for the sensor SRF effect on the Rayleigh radiance computation can be used for other satellite sensors. In addition, with the new Rayleigh LUTs, the effect of surface atmospheric pressure variation on the TOA Rayleigh radiance computation can be calculated precisely, and no specific atmospheric pressure correction algorithm is needed. There are some other important applications and advantages to using the new Rayleigh LUTs for satellite remote sensing, including an efficient and accurate TOA Rayleigh radiance computation for hyperspectral satellite remote sensing, detector-based TOA Rayleigh radiance computation, Rayleigh radiance calculations for high altitude

  7. Spectral response characterization of CdTe sensors of different pixel size with the IBEX ASIC

    Science.gov (United States)

    Zambon, P.; Radicci, V.; Trueb, P.; Disch, C.; Rissi, M.; Sakhelashvili, T.; Schneebeli, M.; Broennimann, C.

    2018-06-01

    We characterized the spectral response of CdTe sensors with different pixel sizes - namely 75, 150 and 300 μm - bonded to the latest generation IBEX single photon counting ASIC developed at DECTRIS, to detect monochromatic X-ray energy in the range 10-60 keV. We present a comparison of pulse height spectra recorded for several energies, showing the dependence on the pixel size of the non-trivial atomic fluorescence and charge sharing effects that affect the detector response. The extracted energy resolution, in terms of full width at half maximum or FWHM, ranges from 1.5 to 4 keV according to the pixel size and chip configuration. We devoted a careful analysis to the Quantum Efficiency and to the Spectral Efficiency - a newly-introduced measure that quantifies the impact of fluorescence and escape phenomena on the spectrum integrity in high- Z material based detectors. We then investigated the influence of the photon flux on the aforementioned quantities up to 180 ṡ 106 cts/s/mm2 and 50 ṡ 106 cts/s/mm2 for the 150 μm and 300 μm pixel case, respectively. Finally, we complemented the experimental data with analytical and with Monte Carlo simulations - taking into account the stochastic nature of atomic fluorescence - with an excellent agreement.

  8. Processing Pipeline of Sugarcane Spectral Response to Characterize the Fallen Plants Phenomenon

    International Nuclear Information System (INIS)

    Solano, Agustín; Hadad, Alejandro; Kemerer, Alejandra

    2016-01-01

    Nowadays, in agronomic systems it is possible to make a variable management of inputs to improve the efficiency of agronomic industry and optimize the logistics of the harvesting process. In this way, it was proposed for sugarcane culture the use of remote sensing tools and computational methods to identify useful areas in the cultivated lands. The objective was to use these areas to make variable management of the crop. When at the moment of harvesting the sugarcane there are fallen stalks, together with them some strange material (vegetal or mineral) is collected. This strange material is not millable and when it enters onto the sugar mill it causes important looses of efficiency in the sugar extraction processes and affects its quality. Considering this issue, the spectral response of sugarcane plants in aerial multispectral images was studied. The spectral response was analyzed in different bands of the electromagnetic spectrum. Then, the aerial images were segmented to obtain homogeneous regions useful for producers to make decisions related to the use of inputs and resources according to the variability of the system (existence of fallen cane and standing cane). The obtained segmentation results were satisfactory. It was possible to identify regions with fallen cane and regions with standing cane with high precision rates. (paper)

  9. Comparison of calculated and measured spectral response and intrinsic efficiency for a boron-loaded plastic neutron detector

    Energy Technology Data Exchange (ETDEWEB)

    Kamykowski, E.A. (Grumman Corporate Research Center, Bethpage, NY (United States))

    1992-07-15

    Boron-loaded scintillators offer the potential for neutron spectrometers with a simplified, peak-shaped response. The Monte Carlo code, MCNP, has been used to calculate the detector characteristics of a scintillator made of a boron-loaded plastic, BC454, for neutrons between 1 and 7 MeV. Comparisons with measurements are made of spectral response for neutron energies between 4 and 6 MeV and of intrinsic efficiencies for neutrons up to 7 MeV. In order to compare the calculated spectra with measured data, enhancements to MCNP were introduced to generate tallies of light output spectra for recoil events terminating in a final capture by {sup 10}B. The comparison of measured and calculated spectra shows agreement in response shape, full width at half maximum, and recoil energy deposition. Intrinsic efficiencies measured to 7 MeV are also in agreement with the MCNP calculations. These results validate the code predictions and affirm the value of MCNP as a useful tool for development of sensor concepts based on boron-loaded plastics. (orig.).

  10. Efficient 3D frequency response modeling with spectral accuracy by the rapid expansion method

    KAUST Repository

    Chu, Chunlei

    2012-07-01

    Frequency responses of seismic wave propagation can be obtained either by directly solving the frequency domain wave equations or by transforming the time domain wavefields using the Fourier transform. The former approach requires solving systems of linear equations, which becomes progressively difficult to tackle for larger scale models and for higher frequency components. On the contrary, the latter approach can be efficiently implemented using explicit time integration methods in conjunction with running summations as the computation progresses. Commonly used explicit time integration methods correspond to the truncated Taylor series approximations that can cause significant errors for large time steps. The rapid expansion method (REM) uses the Chebyshev expansion and offers an optimal solution to the second-order-in-time wave equations. When applying the Fourier transform to the time domain wavefield solution computed by the REM, we can derive a frequency response modeling formula that has the same form as the original time domain REM equation but with different summation coefficients. In particular, the summation coefficients for the frequency response modeling formula corresponds to the Fourier transform of those for the time domain modeling equation. As a result, we can directly compute frequency responses from the Chebyshev expansion polynomials rather than the time domain wavefield snapshots as do other time domain frequency response modeling methods. When combined with the pseudospectral method in space, this new frequency response modeling method can produce spectrally accurate results with high efficiency. © 2012 Society of Exploration Geophysicists.

  11. Newly Diagnosed Breast Cancer: Comparison of Contrast-enhanced Spectral Mammography and Breast MR Imaging in the Evaluation of Extent of Disease.

    Science.gov (United States)

    Lee-Felker, Stephanie A; Tekchandani, Leena; Thomas, Mariam; Gupta, Esha; Andrews-Tang, Denise; Roth, Antoinette; Sayre, James; Rahbar, Guita

    2017-11-01

    Purpose To compare the diagnostic performances of contrast material-enhanced spectral mammography and breast magnetic resonance (MR) imaging in the detection of index and secondary cancers in women with newly diagnosed breast cancer by using histologic or imaging follow-up as the standard of reference. Materials and Methods This institutional review board-approved, HIPAA-compliant, retrospective study included 52 women who underwent breast MR imaging and contrast-enhanced spectral mammography for newly diagnosed unilateral breast cancer between March 2014 and October 2015. Of those 52 patients, 46 were referred for contrast-enhanced spectral mammography and targeted ultrasonography because they had additional suspicious lesions at MR imaging. In six of the 52 patients, breast cancer had been diagnosed at an outside institution. These patients were referred for contrast-enhanced spectral mammography and targeted US as part of diagnostic imaging. Images from contrast-enhanced spectral mammography were analyzed by two fellowship-trained breast imagers with 2.5 years of experience with contrast-enhanced spectral mammography. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value were calculated for both imaging modalities and compared by using the Bennett statistic. Results Fifty-two women with 120 breast lesions were included for analysis (mean age, 50 years; range, 29-73 years). Contrast-enhanced spectral mammography had similar sensitivity to MR imaging (94% [66 of 70 lesions] vs 99% [69 of 70 lesions]), a significantly higher PPV than MR imaging (93% [66 of 71 lesions] vs 60% [69 of 115 lesions]), and fewer false-positive findings than MR imaging (five vs 45) (P contrast-enhanced spectral mammography depicted 11 of the 11 secondary cancers (100%) and MR imaging depicted 10 (91%). Conclusion Contrast-enhanced spectral mammography is potentially as sensitive as MR imaging in the evaluation of extent of disease in newly diagnosed

  12. Contrast-enhanced spectral mammography: Impact of the qualitative morphology descriptors on the diagnosis of breast lesions

    International Nuclear Information System (INIS)

    Mohamed Kamal, Rasha; Hussien Helal, Maha; Wessam, Rasha; Mahmoud Mansour, Sahar; Godda, Iman; Alieldin, Nelly

    2015-01-01

    Highlights: • We studied interpretation criteria for enhancing lesions on CESM. • We evaluated the enhancement patterns of 211 breast lesions. • Our results proved that CESM minimized positive and negative falsies in DM. • The proposed CESM lexicon helped in characterization and categorization. - Abstract: Objective: To analyze the morphology and enhancement characteristics of breast lesions on contrast-enhanced spectral mammography (CESM) and to assess their impact on the differentiation between benign and malignant lesions. Materials and method: This ethics committee approved study included 168 consecutive patients with 211 breast lesions over 18 months. Lesions classified as non-enhancing and enhancing and then the latter group was subdivided into mass and non-mass. Mass lesions descriptors included: shape, margins, pattern and degree of internal enhancement. Non-mass lesions descriptors included: distribution, pattern and degree of internal enhancement. The impact of each descriptor on diagnosis individually assessed using Chi test and the validity compared in both benign and malignant lesions. The overall performance of CESM were also calculated. Results: The study included 102 benign (48.3%) and 109 malignant (51.7%) lesions. Enhancement was encountered in 145/211 (68.7%) lesions. They further classified into enhancing mass (99/145, 68.3%) and non-mass lesions (46/145, 31.7%). Contrast uptake was significantly more frequent in malignant breast lesions (p value ≤0.001). Irregular mass lesions with intense and heterogeneous enhancement patterns correlated with a malignant pathology (p value ≤0.001). CESM showed an overall sensitivity of 88.99% and specificity of 83.33%. The positive and negative likelihood ratios were 5.34 and 0.13 respectively. Conclusion: The assessment of the morphology and enhancement characteristics of breast lesions on CESM enhances the performance of digital mammography in the differentiation between benign and malignant

  13. Contrast-enhanced spectral mammography: Impact of the qualitative morphology descriptors on the diagnosis of breast lesions

    Energy Technology Data Exchange (ETDEWEB)

    Mohamed Kamal, Rasha [Radiology Department (Women' s Imaging unit), Kasr ElAiny Hospital, Cairo University (Egypt); Hussien Helal, Maha [Radiology Department (Breast Imaging unit), National Cancer Institute, Cairo University (Egypt); Wessam, Rasha [Radiology Department (Women' s Imaging unit), Kasr ElAiny Hospital, Cairo University (Egypt); Mahmoud Mansour, Sahar, E-mail: sahar_mnsr@yahoo.com [Radiology Department (Breast Imaging unit), National Cancer Institute, Cairo University (Egypt); Godda, Iman [Pathology Department, National Cancer Institute, Cairo University (Egypt); Alieldin, Nelly [Statistics Department, National Cancer Institute, Cairo University (Egypt)

    2015-06-15

    Highlights: • We studied interpretation criteria for enhancing lesions on CESM. • We evaluated the enhancement patterns of 211 breast lesions. • Our results proved that CESM minimized positive and negative falsies in DM. • The proposed CESM lexicon helped in characterization and categorization. - Abstract: Objective: To analyze the morphology and enhancement characteristics of breast lesions on contrast-enhanced spectral mammography (CESM) and to assess their impact on the differentiation between benign and malignant lesions. Materials and method: This ethics committee approved study included 168 consecutive patients with 211 breast lesions over 18 months. Lesions classified as non-enhancing and enhancing and then the latter group was subdivided into mass and non-mass. Mass lesions descriptors included: shape, margins, pattern and degree of internal enhancement. Non-mass lesions descriptors included: distribution, pattern and degree of internal enhancement. The impact of each descriptor on diagnosis individually assessed using Chi test and the validity compared in both benign and malignant lesions. The overall performance of CESM were also calculated. Results: The study included 102 benign (48.3%) and 109 malignant (51.7%) lesions. Enhancement was encountered in 145/211 (68.7%) lesions. They further classified into enhancing mass (99/145, 68.3%) and non-mass lesions (46/145, 31.7%). Contrast uptake was significantly more frequent in malignant breast lesions (p value ≤0.001). Irregular mass lesions with intense and heterogeneous enhancement patterns correlated with a malignant pathology (p value ≤0.001). CESM showed an overall sensitivity of 88.99% and specificity of 83.33%. The positive and negative likelihood ratios were 5.34 and 0.13 respectively. Conclusion: The assessment of the morphology and enhancement characteristics of breast lesions on CESM enhances the performance of digital mammography in the differentiation between benign and malignant

  14. Speech Enhancement by MAP Spectral Amplitude Estimation Using a Super-Gaussian Speech Model

    Directory of Open Access Journals (Sweden)

    Lotter Thomas

    2005-01-01

    Full Text Available This contribution presents two spectral amplitude estimators for acoustical background noise suppression based on maximum a posteriori estimation and super-Gaussian statistical modelling of the speech DFT amplitudes. The probability density function of the speech spectral amplitude is modelled with a simple parametric function, which allows a high approximation accuracy for Laplace- or Gamma-distributed real and imaginary parts of the speech DFT coefficients. Also, the statistical model can be adapted to optimally fit the distribution of the speech spectral amplitudes for a specific noise reduction system. Based on the super-Gaussian statistical model, computationally efficient maximum a posteriori speech estimators are derived, which outperform the commonly applied Ephraim-Malah algorithm.

  15. Objective assessment of spectral ripple discrimination in cochlear implant listeners using cortical evoked responses to an oddball paradigm.

    Science.gov (United States)

    Lopez Valdes, Alejandro; Mc Laughlin, Myles; Viani, Laura; Walshe, Peter; Smith, Jaclyn; Zeng, Fan-Gang; Reilly, Richard B

    2014-01-01

    Cochlear implants (CIs) can partially restore functional hearing in deaf individuals. However, multiple factors affect CI listener's speech perception, resulting in large performance differences. Non-speech based tests, such as spectral ripple discrimination, measure acoustic processing capabilities that are highly correlated with speech perception. Currently spectral ripple discrimination is measured using standard psychoacoustic methods, which require attentive listening and active response that can be difficult or even impossible in special patient populations. Here, a completely objective cortical evoked potential based method is developed and validated to assess spectral ripple discrimination in CI listeners. In 19 CI listeners, using an oddball paradigm, cortical evoked potential responses to standard and inverted spectrally rippled stimuli were measured. In the same subjects, psychoacoustic spectral ripple discrimination thresholds were also measured. A neural discrimination threshold was determined by systematically increasing the number of ripples per octave and determining the point at which there was no longer a significant difference between the evoked potential response to the standard and inverted stimuli. A correlation was found between the neural and the psychoacoustic discrimination thresholds (R2=0.60, p<0.01). This method can objectively assess CI spectral resolution performance, providing a potential tool for the evaluation and follow-up of CI listeners who have difficulty performing psychoacoustic tests, such as pediatric or new users.

  16. Monte Carlo simulation of the spectral response of beta-particle emitters in LSC systems

    International Nuclear Information System (INIS)

    Ortiz, F.; Los Arcos, J.M.; Grau, A.; Rodriguez, L.

    1992-01-01

    This paper presents a new method to evaluate the counting efficiency and the effective spectra at the output of any dynodic stage, for any pure beta-particle emitter, measured in a liquid scintillation counting system with two photomultipliers working in sum-coincidence mode. The process is carried out by a Monte Carlo simulation procedure that gives the electron distribution, and consequently the counting efficiency, at any dynode, in response to the beta particles emitted, as a function of the figure of merit of the system and the dynodic gains. The spectral outputs for 3 H and 14 C have been computed and compared with experimental data obtained with two sets of quenched radioactive standards of these nuclides. (orig.)

  17. Analytic models of spectral responses of fiber-grating-based interferometers on FMC theory.

    Science.gov (United States)

    Zeng, Xiangkai; Wei, Lai; Pan, Yingjun; Liu, Shengping; Shi, Xiaohui

    2012-02-13

    In this paper the analytic models (AMs) of the spectral responses of fiber-grating-based interferometers are derived from the Fourier mode coupling (FMC) theory proposed recently. The interferometers include Fabry-Perot cavity, Mach-Zehnder and Michelson interferometers, which are constructed by uniform fiber Bragg gratings and long-period fiber gratings, and also by Gaussian-apodized ones. The calculated spectra based on the analytic models are achieved, and compared with the measured cases and those on the transfer matrix (TM) method. The calculations and comparisons have confirmed that the AM-based spectrum is in excellent agreement with the TM-based one and the measured case, of which the efficiency is improved up to ~2990 times that of the TM method for non-uniform-grating-based in-fiber interferometers.

  18. WE-DE-207B-01: Optimization for Contrast-Enhanced Spectral Mammography Based On Photon-Counting Detectors

    Energy Technology Data Exchange (ETDEWEB)

    Ding, H; Molloi, S [University of California, Irvine, CA (United States)

    2016-06-15

    Purpose: To investigate the feasibility of optimizing the imaging parameters for contrast-enhanced spectral mammography based on Si strip photon-counting detectors. Methods: A computer simulation model using polyenergetic spectra from a tungsten anode x-ray tube and a Si-based photon-counting detector was evaluated for contrast-enhanced spectral mammography. The simulation traces the emission of photons from the x-ray source, attenuation through the breast and subsequent absorption in the detector. The breast was modeled as a mixture of adipose and mammary gland tissues with a breast density of 30%. A 4 mm iodine signal with a concentration of 4 mg/ml was used to simulate the enhancement of a lesion. Quantum efficiency of the detector was calculated based on the effective attenuation length in the Si strips. The figure-of-merit (FOM), which was defined as the decomposed iodine signal-to-noise ratio (SNR) with respect to the square root of the mean glandular dose (MGD), was chosen to optimize the imaging parameters, in terms of beam energy, splitting energy, and pre-filtrations for breast of various thicknesses and densities. Results: The optimal imaging parameters, which lead to the highest FOM, were found at a beam energy of 45 kVp with a splitting energy at 34 keV for an averaged breast thickness of 4 cm with a standard 0.75 mm Al pre-filtration. The optimal tube voltage varied slightly from 46 to 44 kVp as the breast thickness increases from 2 to 8 cm. The optimal tube voltage decreased to 42 kVp when the Al pre-filtration was increased to 3 mm. Conclusion: This simulation study predicted the optimal imaging parameters for application of photon-counting spectral mammography to contrast-enhanced imaging. The simulation results laid the ground work for future phantom and clinical studies. Grant funding from Philips Medical Systems.

  19. Temporal and spectral profiles of stimulus-stimulus and stimulus-response conflict processing.

    Science.gov (United States)

    Wang, Kai; Li, Qi; Zheng, Ya; Wang, Hongbin; Liu, Xun

    2014-04-01

    The ability to detect and resolve conflict is an essential function of cognitive control. Laboratory studies often use stimulus-response-compatibility (SRC) tasks to examine conflict processing in order to elucidate the mechanism and modular organization of cognitive control. Inspired by two influential theories regarding cognitive control, the conflict monitoring theory (Botvinick, Braver, Barch, Carter, & Cohen, 2001) and dimensional overlap taxonomy (Kornblum, Hasbroucq, & Osman, 1990), we explored the temporal and spectral similarities and differences between processing of stimulus-stimulus (S-S) and stimulus-response (S-R) conflicts with event related potential (ERP) and time-frequency measures. We predicted that processing of S-S conflict starts earlier than that of S-R conflict and that the two types of conflict may involve different frequency bands. Participants were asked to perform two parallel SRC tasks, both combining the Stroop task (involving S-S conflict) and Simon task (involving S-R conflict). ERP results showed pronounced SRC effects (incongruent vs. congruent) on N2 and P3 components for both S-S and S-R conflicts. In both tasks, SRC effects of S-S conflict took place earlier than those of S-R conflict. Time-frequency analysis revealed that both types of SRC effects modulated theta and alpha bands, while S-R conflict effects additionally modulated power in the beta band. These results indicated that although S-S and S-R conflict processing shared considerable ERP and time-frequency properties, they differed in temporal and spectral dynamics. We suggest that the modular organization of cognitive control should take both commonality and distinction of S-S and S-R conflict processing into consideration. Copyright © 2013 Elsevier Inc. All rights reserved.

  20. Development of Response Spectral Ground Motion Prediction Equations from Empirical Models for Fourier Spectra and Duration of Ground Motion

    Science.gov (United States)

    Bora, S. S.; Scherbaum, F.; Kuehn, N. M.; Stafford, P.; Edwards, B.

    2014-12-01

    In a probabilistic seismic hazard assessment (PSHA) framework, it still remains a challenge to adjust ground motion prediction equations (GMPEs) for application in different seismological environments. In this context, this study presents a complete framework for the development of a response spectral GMPE easily adjustable to different seismological conditions; and which does not suffer from the technical problems associated with the adjustment in response spectral domain. Essentially, the approach consists of an empirical FAS (Fourier Amplitude Spectrum) model and a duration model for ground motion which are combined within the random vibration theory (RVT) framework to obtain the full response spectral ordinates. Additionally, FAS corresponding to individual acceleration records are extrapolated beyond the frequency range defined by the data using the stochastic FAS model, obtained by inversion as described in Edwards & Faeh, (2013). To that end, an empirical model for a duration, which is tuned to optimize the fit between RVT based and observed response spectral ordinate, at each oscillator frequency is derived. Although, the main motive of the presented approach was to address the adjustability issues of response spectral GMPEs; comparison, of median predicted response spectra with the other regional models indicate that presented approach can also be used as a stand-alone model. Besides that, a significantly lower aleatory variability (σbrands it to a potentially viable alternative to the classical regression (on response spectral ordinates) based GMPEs for seismic hazard studies in the near future. The dataset used for the presented analysis is a subset of the recently compiled database RESORCE-2012 across Europe, Middle East and the Mediterranean region.

  1. Contrast-enhanced spectral mammography: Impact of the qualitative morphology descriptors on the diagnosis of breast lesions.

    Science.gov (United States)

    Mohamed Kamal, Rasha; Hussien Helal, Maha; Wessam, Rasha; Mahmoud Mansour, Sahar; Godda, Iman; Alieldin, Nelly

    2015-06-01

    To analyze the morphology and enhancement characteristics of breast lesions on contrast-enhanced spectral mammography (CESM) and to assess their impact on the differentiation between benign and malignant lesions. This ethics committee approved study included 168 consecutive patients with 211 breast lesions over 18 months. Lesions classified as non-enhancing and enhancing and then the latter group was subdivided into mass and non-mass. Mass lesions descriptors included: shape, margins, pattern and degree of internal enhancement. Non-mass lesions descriptors included: distribution, pattern and degree of internal enhancement. The impact of each descriptor on diagnosis individually assessed using Chi test and the validity compared in both benign and malignant lesions. The overall performance of CESM were also calculated. The study included 102 benign (48.3%) and 109 malignant (51.7%) lesions. Enhancement was encountered in 145/211 (68.7%) lesions. They further classified into enhancing mass (99/145, 68.3%) and non-mass lesions (46/145, 31.7%). Contrast uptake was significantly more frequent in malignant breast lesions (p value ≤ 0.001). Irregular mass lesions with intense and heterogeneous enhancement patterns correlated with a malignant pathology (p value ≤ 0.001). CESM showed an overall sensitivity of 88.99% and specificity of 83.33%. The positive and negative likelihood ratios were 5.34 and 0.13 respectively. The assessment of the morphology and enhancement characteristics of breast lesions on CESM enhances the performance of digital mammography in the differentiation between benign and malignant breast lesions. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  2. Enhancing inhibition-induced plasticity in tinnitus--spectral energy contrasts in tailor-made notched music matter.

    Directory of Open Access Journals (Sweden)

    Alwina Stein

    Full Text Available Chronic tinnitus seems to be caused by reduced inhibition among frequency selective neurons in the auditory cortex. One possibility to reduce tinnitus perception is to induce inhibition onto over-activated neurons representing the tinnitus frequency via tailor-made notched music (TMNM. Since lateral inhibition is modifiable by spectral energy contrasts, the question arises if the effects of inhibition-induced plasticity can be enhanced by introducing increased spectral energy contrasts (ISEC in TMNM. Eighteen participants suffering from chronic tonal tinnitus, pseudo randomly assigned to either a classical TMNM or an ISEC-TMNM group, listened to notched music for three hours on three consecutive days. The music was filtered for both groups by introducing a notch filter centered at the individual tinnitus frequency. For the ISEC-TMNM group a frequency bandwidth of 3/8 octaves on each side of the notch was amplified, additionally, by about 20 dB. Before and after each music exposure, participants rated their subjectively perceived tinnitus loudness on a visual analog scale. During the magnetoencephalographic recordings, participants were stimulated with either a reference tone of 500 Hz or a test tone with a carrier frequency representing the individual tinnitus pitch. Perceived tinnitus loudness was significantly reduced after TMNM exposure, though TMNM type did not influence the loudness ratings. Tinnitus related neural activity in the N1m time window and in the so called tinnitus network comprising temporal, parietal and frontal regions was reduced after TMNM exposure. The ISEC-TMNM group revealed even enhanced inhibition-induced plasticity in a temporal and a frontal cortical area. Overall, inhibition of tinnitus related neural activity could be strengthened in people affected with tinnitus by increasing spectral energy contrast in TMNM, confirming the concepts of inhibition-induced plasticity via TMNM and spectral energy contrasts.

  3. Evans blue dye-enhanced imaging of the brain microvessels using spectral focusing coherent anti-Stokes Raman scattering microscopy.

    Directory of Open Access Journals (Sweden)

    Bo-Ram Lee

    Full Text Available We performed dye-enhanced imaging of mouse brain microvessels using spectral focusing coherent anti-Stokes Raman scattering (SF-CARS microscopy. The resonant signals from C-H stretching in forward CARS usually show high background intensity in tissues, which makes CARS imaging of microvessels difficult. In this study, epi-detection of back-scattered SF-CARS signals showed a negligible background, but the overall intensity of resonant CARS signals was too low to observe the network of brain microvessels. Therefore, Evans blue (EB dye was used as contrasting agent to enhance the back-scattered SF-CARS signals. Breakdown of brain microvessels by inducing hemorrhage in a mouse was clearly visualized using backward SF-CARS signals, following intravenous injection of EB. The improved visualization of brain microvessels with EB enhanced the sensitivity of SF-CARS, detecting not only the blood vessels themselves but their integrity as well in the brain vasculature.

  4. MODIS Aqua Optical Throughput Degradation Impact on Relative Spectral Response and Calibration on Ocean Color Products

    Science.gov (United States)

    Lee, Shihyan; Meister, Gerhard

    2017-01-01

    Since Moderate Resolution Imaging Spectroradiometer Aqua's launch in 2002, the radiometric system gains of the reflective solar bands have been degrading, indicating changes in the systems optical throughput. To estimate the optical throughput degradation, the electronic gain changes were estimated and removed from the measured system gain. The derived optical throughput degradation shows a rate that is much faster in the shorter wavelengths than the longer wavelengths. The wavelength-dependent optical throughput degradation modulated the relative spectral response (RSR) of the bands. In addition, the optical degradation is also scan angle-dependent due to large changes in response versus the scan angle over time. We estimated the modulated RSR as a function of time and scan angles and its impacts on sensor radiometric calibration for the ocean science. Our results show that the calibration bias could be up to 1.8 % for band 8 (412 nm) due to its larger out-of-band response. For the other ocean bands, the calibration biases are much smaller with magnitudes at least one order smaller.

  5. Assessing signal-driven mechanism in neonates: brain responses to temporally and spectrally different sounds

    Directory of Open Access Journals (Sweden)

    Yasuyo eMinagawa-Kawai

    2011-06-01

    Full Text Available Past studies have found that in adults that acoustic properties of sound signals (such as fast vs. slow temporal features differentially activate the left and right hemispheres, and some have hypothesized that left-lateralization for speech processing may follow from left-lateralization to rapidly changing signals. Here, we tested whether newborns’ brains show some evidence of signal-specific lateralization responses using near-infrared spectroscopy (NIRS and auditory stimuli that elicits lateralized responses in adults, composed of segments that vary in duration and spectral diversity. We found significantly greater bilateral responses of oxygenated hemoglobin (oxy-Hb in the temporal areas for stimuli with a minimum segment duration of 21 ms, than stimuli with a minimum segment duration of 667 ms. However, we found no evidence for hemispheric asymmetries dependent on the stimulus characteristics. We hypothesize that acoustic-based functional brain asymmetries may develop throughout early infancy, and discuss their possible relationship with brain asymmetries for language.

  6. Geoscience Diversity Enhancement Project: Student Responses.

    Science.gov (United States)

    Rodrigue, Christine M.; Wechsler, Suzanne P.; Whitney, David J.; Ambos, Elizabeth L.; Ramirez-Herrera, Maria Teresa; Behl, Richard; Francis, Robert D.; Larson, Daniel O.; Hazen, Crisanne

    This paper describes an interdisciplinary project at California State University (Long Beach) designed to increase the attractiveness of the geosciences to underrepresented groups. The project is called the Geoscience Diversity Enhancement Project (GDEP). It is a 3-year program which began in the fall of 2001 with funding from the National Science…

  7. Contrast-enhanced spectral mammography versus MRI: Initial results in the detection of breast cancer and assessment of tumour size.

    Science.gov (United States)

    Fallenberg, E M; Dromain, C; Diekmann, F; Engelken, F; Krohn, M; Singh, J M; Ingold-Heppner, B; Winzer, K J; Bick, U; Renz, D M

    2014-01-01

    To compare mammography (MG), contrast-enhanced spectral mammography (CESM), and magnetic resonance imaging (MRI) in the detection and size estimation of histologically proven breast cancers using postoperative histology as the gold standard. After ethical approval, 80 women with newly diagnosed breast cancer underwent MG, CESM, and MRI examinations. CESM was reviewed by an independent experienced radiologist, and the maximum dimension of suspicious lesions was measured. For MG and MRI, routine clinical reports of breast specialists, with judgment based on the BI-RADS lexicon, were used. Results of each imaging technique were correlated to define the index cancer. Fifty-nine cases could be compared to postoperative histology for size estimation. Breast cancer was visible in 66/80 MG, 80/80 CESM, and 77/79 MRI examinations. Average lesion largest dimension was 27.31 mm (SD 22.18) in MG, 31.62 mm (SD 24.41) in CESM, and 27.72 mm (SD 21.51) in MRI versus 32.51 mm (SD 29.03) in postoperative histology. No significant difference was found between lesion size measurement on MRI and CESM compared with histopathology. Our initial results show a better sensitivity of CESM and MRI in breast cancer detection than MG and a good correlation with postoperative histology in size assessment. • Contrast-enhanced spectral mammography (CESM) is slowly being introduced into clinical practice. • Access to breast MRI is limited by availability and lack of reimbursement. • Initial results show a better sensitivity of CESM and MRI than conventional mammography. • CESM showed a good correlation with postoperative histology in size assessment. • Contrast-enhanced spectral mammography offers promise, seemingly providing information comparable to MRI.

  8. Radiative heat transfer enhancement using geometric and spectral control for achieving high-efficiency solar-thermophotovoltaic systems

    Science.gov (United States)

    Kohiyama, Asaka; Shimizu, Makoto; Yugami, Hiroo

    2018-04-01

    We numerically investigate radiative heat transfer enhancement using spectral and geometric control of the absorber/emitter. A high extraction of the radiative heat transfer from the emitter as well as minimization of the optical losses from the absorber leads to high extraction and solar thermophotovoltaic (STPV) system efficiency. The important points for high-efficiency STPV design are discussed for the low and high area ratio of the absorber/emitter. The obtained general guideline will support the design of various types of STPV systems.

  9. Can we apply the MRI BI-RADS lexicon morphology descriptors on contrast-enhanced spectral mammography?

    Science.gov (United States)

    Kamal, Rasha M; Helal, Maha H; Mansour, Sahar M; Haggag, Marwa A; Nada, Omniya M; Farahat, Iman G; Alieldin, Nelly H

    2016-07-12

    To assess the feasibility of using the MRI breast imaging reporting and data system (BI-RADS) lexicon morphology descriptors to characterize enhancing breast lesions identified on contrast-enhanced spectral mammography (CESM). The study is a retrospective analysis of the morphology descriptors of 261 enhancing breast lesions identified on CESM in 239 patients. We presented the morphological categorization of the included lesions into focus, mass and non-mass. Further classifications included (1) the multiplicity for "focus" category, (2) the shape, margin and internal enhancement for "mass" category and (3) the distribution and internal enhancement for "non-mass" category. Each morphology descriptor was evaluated individually (irrespective of all other descriptors) by calculating its sensitivity, specificity, positive-predictive value (PPV) and negative-predictive value (NPV) and likelihood ratios (LRs). The study included 68/261 (26.1%) benign lesions and 193/261 (73.9%) malignant lesions. Intensely enhancing foci, whether single (7/12, 58.3%) or multiple (2/12, 16.7%), were malignant. Descriptors of "irregular"-shape (PPV: 92.4%) and "non-circumscribed" margin (odds ratio: 55.2, LR positive: 4.77; p-value: <0.001) were more compatible with malignancy. Internal mass enhancement patterns showed a very low specificity (58.0%) and NPV (40.0%). Non-mass enhancement (NME) was detected in 81/261 lesions. Asymmetrical NME in 81% (n = 52/81) lesions was malignant lesions and internal enhancement patterns indicative of malignancy were the heterogeneous and clumped ones. We can apply the MRI morphology descriptors to characterize lesions on CESM, but with few expectations. In many situations, irregular-shaped, non-circumscribed masses and NME with focal, ductal or segmental distribution and heterogeneous or clumped enhancement are the most suggestive descriptors of malignant pathologies. (1) The MRI BI-RADS lexicon morphology descriptors can be applied in the

  10. Responsive Copolymers for Enhanced Petroleum Recovery

    Energy Technology Data Exchange (ETDEWEB)

    McCormick, C.; Hester, R.

    2001-02-27

    The objectives of this work was to: synthesize responsive copolymer systems; characterize molecular structure and solution behavior; measure rheological properties of aqueous fluids in fixed geometry flow profiles; and to tailor final polymer compositions for in situ rheology control under simulated conditions. This report focuses on the synthesis and characterization of novel stimuli responsive copolymers, the investigation of dilute polymer solutions in extensional flow and the design of a rheometer capable of measuring very dilute aqueous polymer solutions at low torque.

  11. Using corporate social responsibility to enhance value.

    OpenAIRE

    Taiwo, Waheed

    2012-01-01

    Corporate social responsibility (CSR) has become an important focus in today’s society due to reasons ranging from the new consciousness of people’s impact on the planet to how companies’ excessive pursuit of profit has led to the increased negative impact on people and the environment. As a result of this awareness, companies’ actions are being scrutinised like never before. Even though corporate social responsibility is not a new concept, it has evolved and is known under many different ...

  12. Red-Shift Effects in Surface Enhanced Raman Spectroscopy: Spectral or Intensity Dependence of the Near-Field?

    KAUST Repository

    Colas, Florent; Cottat, Maximilien; Gillibert, Raymond; Guillot, Nicolas; Djaker, Nadia; Lidgi-Guigui, Nathalie; Toury, Timothé e; Barchiesi, Dominique; Toma, Andrea; Di Fabrizio, Enzo M.; Gucciardi, Pietro Giuseppe; de la Chapelle, Marc Lamy

    2016-01-01

    Optimum amplification in Surface Enhanced Raman Scattering (SERS) from individual nanoantennas is expected when the excitation is slightly blue-shifted with respect to the Localized Surface Plasmon Resonance (LSPR), so that the LSPR peak falls in the middle between the laser and the Stokes Raman emission. Recent experiments have shown when moving the excitation from the visible to the near-infrared that this rule of thumb is no more valid. The excitation has to be red-shifted with respect to the LSPR peak, up to 80nm, to obtain highest SERS. Such discrepancy is usually attributed to a Near-Field (NF) to Far-Field (FF) spectral shift. Here we critically discuss this hypothesis for the case of gold nanocylinders. By combining multi-wavelength excitation SERS experiments with numerical calculations, we show that the red-shift of the excitation energy does not originate from a spectral shift between the extinction (FF) and the near-field distribution (NF), which is found to be not larger than 10nm. Rather, it can be accounted for by looking at the peculiar spectral dependence of the near-field intensity on the cylinders diameter, characterized by an initial increase, up to 180nm diameter, followed by a decrease and a pronounced skewness.

  13. Red-Shift Effects in Surface Enhanced Raman Spectroscopy: Spectral or Intensity Dependence of the Near-Field?

    KAUST Repository

    Colas, Florent

    2016-06-06

    Optimum amplification in Surface Enhanced Raman Scattering (SERS) from individual nanoantennas is expected when the excitation is slightly blue-shifted with respect to the Localized Surface Plasmon Resonance (LSPR), so that the LSPR peak falls in the middle between the laser and the Stokes Raman emission. Recent experiments have shown when moving the excitation from the visible to the near-infrared that this rule of thumb is no more valid. The excitation has to be red-shifted with respect to the LSPR peak, up to 80nm, to obtain highest SERS. Such discrepancy is usually attributed to a Near-Field (NF) to Far-Field (FF) spectral shift. Here we critically discuss this hypothesis for the case of gold nanocylinders. By combining multi-wavelength excitation SERS experiments with numerical calculations, we show that the red-shift of the excitation energy does not originate from a spectral shift between the extinction (FF) and the near-field distribution (NF), which is found to be not larger than 10nm. Rather, it can be accounted for by looking at the peculiar spectral dependence of the near-field intensity on the cylinders diameter, characterized by an initial increase, up to 180nm diameter, followed by a decrease and a pronounced skewness.

  14. Auditory enhancement of increments in spectral amplitude stems from more than one source.

    Science.gov (United States)

    Carcagno, Samuele; Semal, Catherine; Demany, Laurent

    2012-10-01

    A component of a test sound consisting of simultaneous pure tones perceptually "pops out" if the test sound is preceded by a copy of itself with that component attenuated. Although this "enhancement" effect was initially thought to be purely monaural, it is also observable when the test sound and the precursor sound are presented contralaterally (i.e., to opposite ears). In experiment 1, we assessed the magnitude of ipsilateral and contralateral enhancement as a function of the time interval between the precursor and test sounds (10, 100, or 600 ms). The test sound, randomly transposed in frequency from trial to trial, was followed by a probe tone, either matched or mismatched in frequency to the test sound component which was the target of enhancement. Listeners' ability to discriminate matched probes from mismatched probes was taken as an index of enhancement magnitude. The results showed that enhancement decays more rapidly for ipsilateral than for contralateral precursors, suggesting that ipsilateral enhancement and contralateral enhancement stem from at least partly different sources. It could be hypothesized that, in experiment 1, contralateral precursors were effective only because they provided attentional cues about the target tone frequency. In experiment 2, this hypothesis was tested by presenting the probe tone before the precursor sound rather than after the test sound. Although the probe tone was then serving as a frequency cue, contralateral precursors were again found to produce enhancement. This indicates that contralateral enhancement cannot be explained by cuing alone and is a genuine sensory phenomenon.

  15. Novel Base Station MIMO Antennas with Enhanced Spectral Efficiencies Using Angular Reuse

    Directory of Open Access Journals (Sweden)

    Miguel Mora-Andreu

    2015-01-01

    Full Text Available The true polarization diversity (TPD technique is combined with the spatial diversity technique in novel MIMO antenna array geometries with a large number of elements. The use of a large number of elements requires some angular reuse within the array for polarization diversity. With designs compatible with existing base station antenna array configurations, the novel geometries with combining diversity schemes are shown to be able to achieve near the maximum spectral efficiencies. True polarization diversity (TPD schemes are found to be an excellent complement to more conventional spatial diversity schemes for obtaining optimum MIMO array performance in base station antennas.

  16. Broadband cavity-enhanced absorption spectroscopy in the ultraviolet spectral region for measurements of nitrogen dioxide and formaldehyde

    Science.gov (United States)

    Washenfelder, R. A.; Attwood, A. R.; Flores, J. M.; Zarzana, K. J.; Rudich, Y.; Brown, S. S.

    2016-01-01

    Formaldehyde (CH2O) is the most abundant aldehyde in the atmosphere, and it strongly affects photochemistry through its photolysis. We describe simultaneous measurements of CH2O and nitrogen dioxide (NO2) using broadband cavity-enhanced absorption spectroscopy in the ultraviolet spectral region. The light source consists of a continuous-wave diode laser focused into a Xenon bulb to produce a plasma that emits high-intensity, broadband light. The plasma discharge is optically filtered and coupled into a 1 m optical cavity. The reflectivity of the cavity mirrors is 0.99930 ± 0.00003 (1- reflectivity = 700 ppm loss) at 338 nm, as determined from the known Rayleigh scattering of He and zero air. This mirror reflectivity corresponds to an effective path length of 1.43 km within the 1 m cell. We measure the cavity output over the 315-350 nm spectral region using a grating monochromator and charge-coupled device array detector. We use published reference spectra with spectral fitting software to simultaneously retrieve CH2O and NO2 concentrations. Independent measurements of NO2 standard additions by broadband cavity-enhanced absorption spectroscopy and cavity ring-down spectroscopy agree within 2 % (slope for linear fit = 1.02 ± 0.03 with r2 = 0.998). Standard additions of CH2O measured by broadband cavity-enhanced absorption spectroscopy and calculated based on flow dilution are also well correlated, with r2 = 0.9998. During constant mixed additions of NO2 and CH2O, the 30 s measurement precisions (1σ) of the current configuration were 140 and 210 pptv, respectively. The current 1 min detection limit for extinction measurements at 315-350 nm provides sufficient sensitivity for measurement of trace gases in laboratory experiments and ground-based field experiments. Additionally, the instrument provides highly accurate, spectroscopically based trace gas detection that may complement higher precision techniques based on non-absolute detection methods. In addition to

  17. Discovery of stimulation-responsive immune enhancers with CRISPR activation

    Science.gov (United States)

    Simeonov, Dimitre R.; Gowen, Benjamin G.; Boontanrart, Mandy; Roth, Theodore L.; Gagnon, John D.; Mumbach, Maxwell R.; Satpathy, Ansuman T.; Lee, Youjin; Bray, Nicolas L.; Chan, Alice Y.; Lituiev, Dmytro S.; Nguyen, Michelle L.; Gate, Rachel E.; Subramaniam, Meena; Li, Zhongmei; Woo, Jonathan M.; Mitros, Therese; Ray, Graham J.; Curie, Gemma L.; Naddaf, Nicki; Chu, Julia S.; Ma, Hong; Boyer, Eric; van Gool, Frederic; Huang, Hailiang; Liu, Ruize; Tobin, Victoria R.; Schumann, Kathrin; Daly, Mark J.; Farh, Kyle K.; Ansel, K. Mark; Ye, Chun J.; Greenleaf, William J.; Anderson, Mark S.; Bluestone, Jeffrey A.; Chang, Howard Y.; Corn, Jacob E.; Marson, Alexander

    2017-09-01

    The majority of genetic variants associated with common human diseases map to enhancers, non-coding elements that shape cell-type-specific transcriptional programs and responses to extracellular cues. Systematic mapping of functional enhancers and their biological contexts is required to understand the mechanisms by which variation in non-coding genetic sequences contributes to disease. Functional enhancers can be mapped by genomic sequence disruption, but this approach is limited to the subset of enhancers that are necessary in the particular cellular context being studied. We hypothesized that recruitment of a strong transcriptional activator to an enhancer would be sufficient to drive target gene expression, even if that enhancer was not currently active in the assayed cells. Here we describe a discovery platform that can identify stimulus-responsive enhancers for a target gene independent of stimulus exposure. We used tiled CRISPR activation (CRISPRa) to synthetically recruit a transcriptional activator to sites across large genomic regions (more than 100 kilobases) surrounding two key autoimmunity risk loci, CD69 and IL2RA. We identified several CRISPRa-responsive elements with chromatin features of stimulus-responsive enhancers, including an IL2RA enhancer that harbours an autoimmunity risk variant. Using engineered mouse models, we found that sequence perturbation of the disease-associated Il2ra enhancer did not entirely block Il2ra expression, but rather delayed the timing of gene activation in response to specific extracellular signals. Enhancer deletion skewed polarization of naive T cells towards a pro-inflammatory T helper (TH17) cell state and away from a regulatory T cell state. This integrated approach identifies functional enhancers and reveals how non-coding variation associated with human immune dysfunction alters context-specific gene programs.

  18. Discovery of stimulation-responsive immune enhancers with CRISPR activation

    Science.gov (United States)

    Simeonov, Dimitre R.; Gowen, Benjamin G.; Boontanrart, Mandy; Roth, Theodore L.; Gagnon, John D.; Mumbach, Maxwell R.; Satpathy, Ansuman T.; Lee, Youjin; Bray, Nicolas L.; Chan, Alice Y.; Lituiev, Dmytro S.; Nguyen, Michelle L.; Gate, Rachel E.; Subramaniam, Meena; Li, Zhongmei; Woo, Jonathan M.; Mitros, Therese; Ray, Graham J.; Curie, Gemma L.; Naddaf, Nicki; Chu, Julia S.; Ma, Hong; Boyer, Eric; Van Gool, Frederic; Huang, Hailiang; Liu, Ruize; Tobin, Victoria R.; Schumann, Kathrin; Daly, Mark J.; Farh, Kyle K; Ansel, K. Mark; Ye, Chun J.; Greenleaf, William J.; Anderson, Mark S.; Bluestone, Jeffrey A.; Chang, Howard Y.; Corn, Jacob E.; Marson, Alexander

    2017-01-01

    The majority of genetic variants associated with common human diseases map to enhancers, non-coding elements that shape cell-type-specific transcriptional programs and responses to extracellular cues1–3. Systematic mapping of functional enhancers and their biological contexts is required to understand the mechanisms by which variation in non-coding genetic sequences contributes to disease. Functional enhancers can be mapped by genomic sequence disruption4–6, but this approach is limited to the subset of enhancers that are necessary in the particular cellular context being studied. We hypothesized that recruitment of a strong transcriptional activator to an enhancer would be sufficient to drive target gene expression, even if that enhancer was not currently active in the assayed cells. Here we describe a discovery platform that can identify stimulus-responsive enhancers for a target gene independent of stimulus exposure. We used tiled CRISPR activation (CRISPRa)7 to synthetically recruit a transcriptional activator to sites across large genomic regions (more than 100 kilobases) surrounding two key autoimmunity risk loci, CD69 and IL2RA. We identified several CRISPRa-responsive elements with chromatin features of stimulus-responsive enhancers, including an IL2RA enhancer that harbours an autoimmunity risk variant. Using engineered mouse models, we found that sequence perturbation of the disease-associated Il2ra enhancer did not entirely block Il2ra expression, but rather delayed the timing of gene activation in response to specific extracellular signals. Enhancer deletion skewed polarization of naive T cells towards a pro-inflammatory T helper (TH17) cell state and away from a regulatory T cell state. This integrated approach identifies functional enhancers and reveals how non-coding variation associated with human immune dysfunction alters context-specific gene programs. PMID:28854172

  19. Aversive Life Events Enhance Human Freezing Responses

    NARCIS (Netherlands)

    Hagenaars, M.A.; Stins, J.F.; Roelofs, K.

    2012-01-01

    In the present study, we investigated the effect of prior aversive life events on freezing-like responses. Fifty healthy females were presented neutral, pleasant, and unpleasant images from the International Affective Picture System while standing on a stabilometric platform and wearing a polar band

  20. Aversive life events enhance human freezing responses

    NARCIS (Netherlands)

    Hagenaars, M.A.; Stins, J.F.; Roelofs, K.

    2012-01-01

    In the present study, we investigated the effect of prior aversive life events on freezing-like responses. Fifty healthy females were presented neutral, pleasant, and unpleasant images from the International Affective Picture System while standing on a stabilometric platform and wearing a polar band

  1. Enhancing co-responsibility for patient engagement

    NARCIS (Netherlands)

    Neutelings, I.M.P.; Levy, P.D.; Djajadiningrat, J.P.; Hummels, C.C.M.

    2017-01-01

    ABSTRACT:In this paper we share a theoretical perspective of co-responsibility, developed by a consortium of a university, a private company and a hospital. On this perspective we will base design interventions towards improving the experience and specifically the engagement of cardiovascular

  2. Responsive Copolymers for Enhanced Petroleum Recovery

    Energy Technology Data Exchange (ETDEWEB)

    McCormick, Charles; Hester, Roger

    2002-02-27

    The objectives of this work was to: (1) synthesize responsive, amphiphilic systems; (2) characterize molecular structure and solution behavior; (3) measure rheological properties of the aqueous fluids including behavior in fixed geometry flow profiles and beds; and (4) to tailor polymer compositions for in situ rheology control under simulated reservoir conditions.

  3. Determination of the electron-hole pair creation energy for semiconductors from the spectral responsivity of photodiodes

    CERN Document Server

    Scholze, F; Kuschnerus, P; Rabus, H; Richter, M; Ulm, G

    2000-01-01

    Ionizing radiation can be detected by the measurement of the charge carriers produced in a detector. The improved semiconductor technology now allows detectors operating near the physical limits of the detector materials to be designed. The mean energy required for producing an electron-hole pair, W, is a material property of the semiconductor. Here, the determination of W from the spectral responsivity of photodiodes is demonstrated. Using spectrally dispersed synchrotron radiation, different types of semiconductor photodiodes have been examined in the UV-, VUV-, and soft X-ray spectral range. Their spectral responsivity was determined with relative uncertainties between 0.4% and 1% using a cryogenic electrical-substitution radiometer as primary detector standard. Results are presented for silicon n-on-p junction photodiodes and for GaAsP/Au Schottky diodes at room temperature. The investigations for silicon covered the complete spectral range from 3 to 1500 eV, yielding a constant value W=(3.66+-0.03) eV fo...

  4. Eddy covariance measurements with a new fast-response, enclosed-path analyzer: Spectral characteristics and cross-system comparisons

    Science.gov (United States)

    K. Novick; J. Walker; W.S. Chan; A. Schmidt; C. Sobek; J.M. Vose

    2013-01-01

    A new class of enclosed path gas analyzers suitable for eddy covariance applications combines the advantages of traditional closed-path systems (small density corrections, good performance in poor weather) and open-path systems (good spectral response, low power requirements), and permits estimates of instantaneous gas mixing ratio. Here, the extent to which these...

  5. On the detection and monitoring of reduced water content in plants using spectral responses in the visible domain

    Science.gov (United States)

    Baranoski, Gladimir V. G.; Van Leeuwen, Spencer; Chen, Tenn F.

    2016-05-01

    The water status of cultivated plants can have a significant impact not only on food production, but also on the appropriate usage of increasingly scarce freshwater supplies. Accordingly, the cost-effective detection and monitoring of changes in their water content are longstanding remote sensing goals. Existing procedures employed to achieve these goals are largely based on the spectral responses of plant leaves in the infrared domain where the light absorption within the foliar tissues is dominated by water. Recently, it has been suggested that such procedures could be implemented using spectral responses, more specifically spectral subsurface reflectance to transmittance ratios, obtained in the visible domain. The basis for this proposition resides on the premise that a reduced water content (RWC) can result in histological changes whose effects on the foliar optical properties may not be limited to the infrared domain. However, the experiments leading to this proposition were performed on detached leaves, which were not influenced by the whole plant's adaptation mechanisms to water stress. In this work, we investigate whether the spectral responses of living plant leaves in the visible domain can lead to reliable RWC estimations. We employ measured biophysical data and predictive light transport simulations in order to extend qualitatively and quantitatively the scope of previous studies in this area. Our findings indicate that the living specimens' physiological responses to water stress should be taken into account in the design of new procedures for the cost-effective RWC estimation using visible subsurface reflectance to transmittance ratios.

  6. Nanoparticle-enhanced spectral photoacoustic tomography: effect of oxygen saturation and tissue heterogeneity

    Science.gov (United States)

    Vogt, William C.; Jia, Congxian; Wear, Keith A.; Garra, Brian S.; Pfefer, T. Joshua

    2016-03-01

    Molecular imaging for breast cancer detection, infectious disease diagnostics and preclinical animal research may be achievable through combined use of targeted exogenous agents - such as nanoparticles - and spectral Photoacoustic Tomography (PAT). However, tissue heterogeneity can alter fluence distributions and acoustic propagation, corrupting measured PAT absorption spectra and complicating in vivo nanoparticle detection and quantitation. Highly absorptive vascular structures represent a common confounding factor, and variations in vessel hemoglobin saturation (SO2) may alter spectral content of signals from adjacent/deeper regions. To evaluate the impact of this effect on PAT nanoparticle detectability, we constructed heterogeneous phantoms with well-characterized channel-inclusion geometries and biologically relevant optical and acoustic properties. Phantoms contained an array of tubes at several depths filled with hemoglobin solutions doped with varying concentrations of gold nanorods with an absorption peak at 780 nm. Both overlying and target network SO2 was tuned using sodium dithionite. Phantoms were imaged from 700 to 900 nm using a custom PAT system comprised of a tunable pulsed laser and a research-grade ultrasound system. Recovered nanoparticle spectra were analyzed and compared with results from both spectrophotometry and PAT data from waterimmersed tubes containing blood and nanoparticle solutions. Results suggested that nanoparticle selection for a given PAT application should take into account expected oxygenation states of both target blood vessel and background tissue oxygenation to achieve optimal performance.

  7. Enhancing solar cell efficiency: the search for luminescent materials as spectral converters.

    Science.gov (United States)

    Huang, Xiaoyong; Han, Sanyang; Huang, Wei; Liu, Xiaogang

    2013-01-07

    Photovoltaic (PV) technologies for solar energy conversion represent promising routes to green and renewable energy generation. Despite relevant PV technologies being available for more than half a century, the production of solar energy remains costly, largely owing to low power conversion efficiencies of solar cells. The main difficulty in improving the efficiency of PV energy conversion lies in the spectral mismatch between the energy distribution of photons in the incident solar spectrum and the bandgap of a semiconductor material. In recent years, luminescent materials, which are capable of converting a broad spectrum of light into photons of a particular wavelength, have been synthesized and used to minimize the losses in the solar-cell-based energy conversion process. In this review, we will survey recent progress in the development of spectral converters, with a particular emphasis on lanthanide-based upconversion, quantum-cutting and down-shifting materials, for PV applications. In addition, we will also present technical challenges that arise in developing cost-effective high-performance solar cells based on these luminescent materials.

  8. Responsive copolymers for enhanced petroleum recovery

    Energy Technology Data Exchange (ETDEWEB)

    McCormick, Charles; Hester, Roger

    2000-06-13

    The objectives of this work were to: synthesize responsive, amphiphilic systems; characterize molecular structure and solution behavior; measure rheological properties of the aqueous fluids including behavior in fixed geometry flow profiles and beds; and to tailor final polymer compositions for in situ rheology control under simulated reservoir conditions. This report focuses on the first phase of the research emphasizing synthesis and the development of photophysical techniques and rheological means of following segmental organization at the structural level.

  9. Biological Response to the Dynamic Spectral-Polarized Underwater Light Field

    Science.gov (United States)

    2010-01-01

    Texas coastal fish skin preparations with the HyperSpectral Imager mounted on a stereomicroscope in Norway in April (Dierssen). g) Camouflage...on fish skin preparations. B) Matlab image of skin preparation showing the boxed area used in the spectral analysis. C) Median reflectance

  10. Dependence of surface-enhanced infrared absorption (SEIRA) enhancement and spectral quality on the choice of underlying substrate: a closer look at silver (Ag) films prepared by physical vapor deposition (PVD).

    Science.gov (United States)

    Killian, Michelle M; Villa-Aleman, Eliel; Sun, Zhelin; Crittenden, Scott; Leverette, Chad L

    2011-03-01

    Silver (Ag) films of varying thickness were simultaneously deposited using physical vapor deposition (PVD) onto six infrared (IR) substrates (BaF(2), CaF(2), Ge, AMTIR, KRS-5, and ZnSe) in order to correlate the morphology of the deposited film with optimal SEIRA response and spectral band symmetry and quality. Significant differences were observed in the surface morphology of the deposited silver films, the degree of enhancement provided, and the spectral appearance of para-nitrobenzoic acid (PNBA) cast films for each silver-coated substrate. These differences were attributed to each substrate's chemical properties, which dictate the morphology of the Ag film and ultimately determine the spectral appearance of the adsorbed analyte and the magnitude of SEIRA enhancement. Routine SEIRA enhancement factors (EFs) for all substrates were between 5 and 150. For single-step Ag depositions, the following ranking identifies the greatest SEIRA enhancement factor and the maximum absorption of the 1345 cm(-1) spectral marker of PNBA at the optimal silver thickness for each substrate: BaF(2) (EF = 85 ± 19, 0.059 A, 10 nm Ag) > CaF(2) (EF = 75 ± 30, 0.052 A, 10 nm Ag) > Ge (EF = 45 ± 8, 0.019 A, 5 nm Ag) > AMTIR (EF = 38 ± 8, 0.024 A, 15 nm Ag) > KRS-5 (EF = 24 ± 1, 0.015 A, 12 nm Ag) > ZnSe (EF = 9 ± 5, 0.008 A, 8 nm Ag). A two-step deposition provides 59% larger EFs than single-step depositions of Ag on CaF(2). A maximum EF of 147 was calculated for a cast film of PNBA (surface coverage = 341 ng/cm(2)) on a 10 nm two-step Ag film on CaF(2) (0.102 A, 1345 cm(-1) symmetric NO(2) stretching band). The morphology of the two-step Ag film has smaller particles and greater particle density than the single-step Ag film.

  11. MoS2-InGaZnO Heterojunction Phototransistors with Broad Spectral Responsivity.

    Science.gov (United States)

    Yang, Jaehyun; Kwak, Hyena; Lee, Youngbin; Kang, Yu-Seon; Cho, Mann-Ho; Cho, Jeong Ho; Kim, Yong-Hoon; Jeong, Seong-Jun; Park, Seongjun; Lee, Hoo-Jeong; Kim, Hyoungsub

    2016-04-06

    We introduce an amorphous indium-gallium-zinc-oxide (a-IGZO) heterostructure phototransistor consisting of solution-based synthetic molybdenum disulfide (few-layered MoS2, with a band gap of ∼1.7 eV) and sputter-deposited a-IGZO (with a band gap of ∼3.0 eV) films as a novel sensing element with a broad spectral responsivity. The MoS2 and a-IGZO films serve as a visible light-absorbing layer and a high mobility channel layer, respectively. Spectroscopic measurements reveal that appropriate band alignment at the heterojunction provides effective transfer of the visible light-induced electrons generated in the few-layered MoS2 film to the underlying a-IGZO channel layer with a high carrier mobility. The photoresponse characteristics of the a-IGZO transistor are extended to cover most of the visible range by forming a heterojunction phototransistor that harnesses a visible light responding MoS2 film with a small band gap prepared through a large-area synthetic route. The MoS2-IGZO heterojunction phototransistors exhibit a photoresponsivity of approximately 1.7 A/W at a wavelength of 520 nm (an optical power of 1 μW) with excellent time-dependent photoresponse dynamics.

  12. A comparison of electrophysiologically determined spectral responses in six subspecies of Lymantria.

    Science.gov (United States)

    Crook, Damon J; Hull-Sanders, Helen M; Hibbard, Emily L; Mastro, Victor C

    2014-04-01

    The spectral sensitivity of the compound eye in three gypsy moth species from six different geographical regions (Lymantria dispar asiatica Vnukovskij [Asian gypsy moth], Lymantria dispar japonica Motschulsky [Japanese gypsy moth], and Lymantria dispar dispar L. [North American gypsy moth]) was tested electrophysiologically in the wavelength region 300-700 nm. For all moths examined, a maximum response occurred in the 480-520-nm range (blue-green region) with a shoulder peak occurring at 460 nm. A smaller, secondary peak was observed for both sexes at the 340-380-nm range, which is in the region considered behaviorally maximal in night-flying insects. No peaks in sensitivity were observed between 520 and 700 nm (red region) for any of the moths tested. Based on our retinal recording data, a short wavelength blocking filter with a transition wavelength near 500 nm should reduce gypsy moth attraction to artificial lighting sources. This would help reduce the number of Lymantria-infested ships traveling to and from foreign ports.

  13. Clinical utility of dual-energy contrast-enhanced spectral mammography for breast microcalcifications without associated mass: a preliminary analysis.

    Science.gov (United States)

    Cheung, Yun-Chung; Tsai, Hsiu-Pei; Lo, Yung-Feng; Ueng, Shir-Hwa; Huang, Pei-Chin; Chen, Shin-Chih

    2016-04-01

    To assess the utility of dual-energy contrast-enhanced spectral mammography (DE-CESM) for evaluation of suspicious malignant microcalcifications. Two hundred and fifty-six DE-CESMs were reviewed from 2012-2013, 59 cases fulfilled the following criteria and were enrolled for analysis: (1) suspicious malignant microcalcifications (BI-RADS 4) on mammogram, (2) no related mass, (3) with pathological diagnoses. The microcalcification morphology and associated enhancement were reviewed to analyse the accuracy of the diagnosis and cancer size measurements versus the results of pathology. Of the 59 microcalcifications, 22 were diagnosed as cancers, 19 were atypical lesions and 18 were benign lesions. Twenty (76.9 %) cancers, three (11.55 %) atypia and three (11.55 %) benign lesions revealed enhancement. The true-positive rate of intermediate- and high-concern microcalcifications was significantly higher than that of low-concern lesions (93.75 % vs. 50 %). Overall, the diagnostic sensitivity of enhancement was 90.9 %, with 83.78 % specificity, 76.92 % positive predictive value, 93.94 % negative predictive value and 86.4 % accuracy. Performance was good (AUC = 0.87) according to a ROC curve and cancer size correlation with a mean difference of 0.05 cm on a Bland-Altman plot. DE-CESM provides additional enhancement information for diagnosing breast microcalcifications and measuring cancer sizes with high correlation to surgicohistology. • DE-CESM provides additional enhancement information for diagnosing suspicious breast microcalcifications. • The enhanced cancer size closely correlates to microscopy by Bland-Altman plot. • DE-CESM could be considered for evaluation of suspicious malignant microcalcifications.

  14. Spectral Imaging by Upconversion

    DEFF Research Database (Denmark)

    Dam, Jeppe Seidelin; Pedersen, Christian; Tidemand-Lichtenberg, Peter

    2011-01-01

    We present a method to obtain spectrally resolved images using upconversion. By this method an image is spectrally shifted from one spectral region to another wavelength. Since the process is spectrally sensitive it allows for a tailored spectral response. We believe this will allow standard...... silicon based cameras designed for visible/near infrared radiation to be used for spectral images in the mid infrared. This can lead to much lower costs for such imaging devices, and a better performance....

  15. A Novel Technique to Enhance Demand Responsiveness

    DEFF Research Database (Denmark)

    Farashbashi-Astaneh, Seyed-Mostafa; Bhattarai, Bishnu Prasad; Bak-Jensen, Birgitte

    2015-01-01

    In this study, a new pricing approach is proposed to increase demand responsiveness. The proposed approach considers two well-known demand side management techniques, namely peak shaving and valley filling. This is done by incentivising consumers by magnifying price difference between peak and off......-peak hours. The usefulness of the suggested method is then investigated by its combination with an electric vehicle optimal scheduling methodology which captures both economic valuation and grid technical constraints. This case is chosen in this study to address network congestion issues, namely under...

  16. Enhancement of increments in spectral amplitude: further evidence for a mechanism based on central adaptation.

    Science.gov (United States)

    Carcagno, Samuele; Semal, Catherine; Demany, Laurent

    2013-01-01

    The threshold for detecting a tone in a multitone masker is lower when the masker-plus-signal stimulus is preceded by a copy of the masker. One potential explanation of this "enhancement" phenomenon is that the -precursor stimulus acts as a "template" of the subsequent masker, thus helping listeners to segregate the signal from the masker. To assess this idea, we measured enhancement for precursors that were perceptually similar to the masker and for precursors that were made dissimilar to the masker by gating their components asynchronously. We found that the two types of precursor produced similar amounts of enhancement. This was true not only when the precursor and the subsequent test stimulus were presented to the same ear but also when they were presented to opposite ears. In a second experiment, we checked that the precursors with asynchronously gated components were perceptually poor templates of the subsequent maskers. Listeners now had to discriminate between test stimuli -containing the same components as the precursor and test stimuli containing all but one of the precursor components. We found that in this experimental situation, where enhancement could play no role, gating the precursor components asynchronously disrupted performance. Overall, our results are inconsistent with the hypothesis that precursors producing enhancement are beneficial because they are used as perceptual templates of the masker. Our results are instead consistent with an -explanation of enhancement based on selective neural adaptation taking place at a central locus of the auditory system.

  17. A standard comparison of spectral properties and energy response for a number of ultraviolet dosimeters

    International Nuclear Information System (INIS)

    Abu Kassem, I.; Bero, M.

    2013-09-01

    The radio-chromic chemical radiation dosimeters are materials that change their optical properties (Spectrique optical absorbance and optical density) due to radiation absorption. These detectors are used for dose measurements of ionizing radiation (γ and X-rays). It was established that these detectors could be used for ultraviolet radiation dose measurements. So, the aim of this work is to study and compare the metrological properties of two radiation chemical detectors, FXG gel and EBT2 Gafchromic film. The FXG gel is prepared directly at laboratory but EBT2 gafchromic film is a self developed radiation sensible film which is available as commercial product. This work focuses on realizing a comparison study between FXG and EBT2 detector metrological properties. It consists of studying optical and spectral properties of the detectors responsivity, radiation and temporal stability, linearity and total detected dose level. The results showed that the studied detectors present a very good responsivity to UVA radiation, high stability in optical absorbance under UVA radiation and good linearity over wide radiation level which contains the solar UVA radiation level reaching the earth surface. But, the EBT2 film presents two time higher total detection dose level than FXG gel, moreover, due to the simplicity of use, it was possible to test the use of EBT2 film for direct solar UVA radiation measurement. The two studied chemical detector (FXG gel and EBT2 film) provide a direct second order mathematical relation between the applied radiation dose and the optical absorbance changes with a very good approximation and suitable uncertainty (Measurement results relative dispersion is about 5%). It is possible to study the EBT2 film optical density variation as a function of UVA dose using directly a portable densitometer (author).

  18. Early developmental responses to seedling environment modulate later plasticity to light spectral quality.

    Directory of Open Access Journals (Sweden)

    Eric J B von Wettberg

    Full Text Available Correlations between developmentally plastic traits may constrain the joint evolution of traits. In plants, both seedling de-etiolation and shade avoidance elongation responses to crowding and foliage shade are mediated by partially overlapping developmental pathways, suggesting the possibility of pleiotropic constraints. To test for such constraints, we exposed inbred lines of Impatiens capensis to factorial combinations of leaf litter (which affects de-etiolation and simulated foliage shade (which affects phytochrome-mediated shade avoidance. Increased elongation of hypocotyls caused by leaf litter phenotypically enhanced subsequent elongation of the first internode in response to low red:far red (R:FR. Trait expression was correlated across litter and shade conditions, suggesting that phenotypic effects of early plasticity on later plasticity may affect variation in elongation traits available to selection in different light environments.

  19. Simulation for spectral response of solar-blind AlGaN based p-i-n photodiodes

    Science.gov (United States)

    Xue, Shiwei; Xu, Jintong; Li, Xiangyang

    2015-04-01

    In this article, we introduced how to build a physical model of refer to the device structure and parameters. Simulations for solar-blind AlGaN based p-i-n photodiodes spectral characteristics were conducted in use of Silvaco TCAD, where device structure and parameters are comprehensively considered. In simulation, the effects of polarization, Urbach tail, mobility, saturated velocities and lifetime in AlGaN device was considered. Especially, we focused on how the concentration-dependent Shockley-Read-Hall (SRH) recombination model affects simulation results. By simulating, we analyzed the effects in spectral response caused by TAUN0 and TAUP0, and got the values of TAUN0 and TAUP0 which can bring a result coincides with test results. After that, we changed their values and made the simulation results especially the part under 255 nm performed better. In conclusion, the spectral response between 200 nm and 320 nm of solar-blind AlGaN based p-i-n photodiodes were simulated and compared with test results. We also found that TAUN0 and TAUP0 have a large impact on spectral response of AlGaN material.

  20. Broad spectral photocurrent enhancement in Au-decorated CdSe nanowires

    KAUST Repository

    Chakraborty, Ritun; Greullet, Fanny; George, Chandramohan; Baranov, Dmitry; Di Fabrizio, Enzo M.; Krahne, Roman

    2013-01-01

    Metal-semiconductor hybrid nanostructures promise improved photoconductive performance due to plasmonic properties of the metal portions and intrinsic electric fields at the metal-semiconductor interface that possibly enhance charge separation. Here we report gold decorated CdSe nanowires as a novel functional material and investigate the influence of gold decoration on the lateral facets on the photoconductive properties. Gold decorated nanowires show typically an at least ten-fold higher photocurrent as compared to their bare counterparts. Interestingly, the photocurrent enhancement is wavelength independent, although the plasmon resonance related to the gold particles appears in the absorption spectra. Our experiments show that light scattering and Schottky fields associated with the metal-semiconductor interface are at the origin of the photocurrent enhancement. © 2013 The Royal Society of Chemistry.

  1. Contrast-enhanced spectral mammography (CESM) versus breast magnetic resonance imaging (MRI): A retrospective comparison in 66 breast lesions.

    Science.gov (United States)

    Li, L; Roth, R; Germaine, P; Ren, S; Lee, M; Hunter, K; Tinney, E; Liao, L

    2017-02-01

    The purpose of this study was to retrospectively compare the diagnostic performance of contrast-enhanced spectral mammography (CESM) with that of breast magnetic resonance imaging (BMRI) in breast cancer detection using parameters, including sensitivity, positive predictive value (PPV), lesion size, morphology, lesion and background enhancement, and examination time. A total of 48 women (mean age, 56years±10.6 [SD]) with breast lesions detected between October 2012 and March 2014 were included. Both CESM and BMRI were performed for each patient within 30 days. The enhancement intensity of lesions and breast background parenchyma was subjectively assessed for both modalities and was quantified for comparison. Statistical significance was analyzed using paired t-test for mean size of index lesions in all malignant breasts (an index lesion defined as the largest lesion in each breast), and a mean score of enhancement intensity for index lesions and breast background. PPV, sensitivity, and accuracy were calculated for both CESM and BMRI. The average duration time of CESM and MRI examinations was also compared. A total of 66 lesions were identified, including 62 malignant and 4 benign lesions. Both CESM and BMRI demonstrated a sensitivity of 100% for detection of breast cancer. There was no statistically significant difference between the mean size of index lesions (P=0.108). The enhancement intensity of breast background was significantly lower for CESM than for BMRI (P0.05). The average examination time for CESM was significantly shorter than that of BMRI (P<0.01). CESM has similar sensitivity than BMRI in breast cancer detection, with higher PPV and less background enhancement. CESM is associate with significantly shorter exam time thus a more accessible alternative to BMRI, and has the potential to play an important tool in breast cancer detection and staging. Copyright © 2016 Éditions françaises de radiologie. Published by Elsevier Masson SAS. All rights

  2. ACR-1000: Enhanced response to severe accidents

    International Nuclear Information System (INIS)

    Popov, N.K.; Santamaura, P.; Shapiro, H.; Snell, V.G.

    2006-01-01

    Full text: Atomic Energy of Canada Limited (AECL) developed the Advanced CANDU Reactor-TM700 (ACR-700TM) as an evolutionary advancement of the current CANDU 6R reactor. As further advancement of the ACR design, AECL is currently developing the ACR-1000TM for the Canadian and international market. The ACR-1000 is aimed at producing electrical power for a capital cost and a unit-energy cost significantly less than that of the current generation of operating nuclear plants, while achieving shorter construction schedule, high plant capacity factor, improved operations and maintenance, increased operating life. and enhanced safety features. The reference ACR-1000 plant design is based on an integrated two-unit plant, using enriched fuel and light-water coolant, with each unit having a nominal gross output of about 1200 MWe. This paper presents the ACR-1000 features that are designed to mitigate limited core damage and severe core damage states, including core retention within vessel, core damage termination, and containment integrity maintenance. Core retention within vessel in CANDU-type reactors includes both retention within fuel channels, and retention within the calandria vessel. The moderator heavy water in the ACR-1000 calandria vessel, as in any other CANDU-type reactor, provides ample heat removal capacity in severe accidents. The ACR-1000 calandria vessel design permits for passive rejection of decay heat from the moderator to the shield water. Also, the calandria vessel will be designed for debris retention. Core damage termination is achieved by flooding of the core components with water and keeping them flooded thereafter. Successful termination can be achieved in the fuel channels, calandria vessel or calandria vault by water supply by the Long Term Cooling (LTC) pumps and by gravity feed from the Reserve Water System. The ACR-1000 containment is required to withstand external events such as earthquakes, tornados, floods and aircraft crashes. Containment

  3. Statistically Optimized Inversion Algorithm for Enhanced Retrieval of Aerosol Properties from Spectral Multi-Angle Polarimetric Satellite Observations

    Science.gov (United States)

    Dubovik, O; Herman, M.; Holdak, A.; Lapyonok, T.; Taure, D.; Deuze, J. L.; Ducos, F.; Sinyuk, A.

    2011-01-01

    The proposed development is an attempt to enhance aerosol retrieval by emphasizing statistical optimization in inversion of advanced satellite observations. This optimization concept improves retrieval accuracy relying on the knowledge of measurement error distribution. Efficient application of such optimization requires pronounced data redundancy (excess of the measurements number over number of unknowns) that is not common in satellite observations. The POLDER imager on board the PARASOL microsatellite registers spectral polarimetric characteristics of the reflected atmospheric radiation at up to 16 viewing directions over each observed pixel. The completeness of such observations is notably higher than for most currently operating passive satellite aerosol sensors. This provides an opportunity for profound utilization of statistical optimization principles in satellite data inversion. The proposed retrieval scheme is designed as statistically optimized multi-variable fitting of all available angular observations obtained by the POLDER sensor in the window spectral channels where absorption by gas is minimal. The total number of such observations by PARASOL always exceeds a hundred over each pixel and the statistical optimization concept promises to be efficient even if the algorithm retrieves several tens of aerosol parameters. Based on this idea, the proposed algorithm uses a large number of unknowns and is aimed at retrieval of extended set of parameters affecting measured radiation.

  4. Cultures differ in the ability to enhance affective neural responses.

    Science.gov (United States)

    Varnum, Michael E W; Hampton, Ryan S

    2017-10-01

    The present study (N = 55) used an event-related potential paradigm to investigate whether cultures differ in the ability to upregulate affective responses. Using stimuli selected from the International Affective Picture System, we found that European-Americans (N = 29) enhanced central-parietal late positive potential (LPP) (400-800 ms post-stimulus) responses to affective stimuli when instructed to do so, whereas East Asians (N = 26) did not. We observed cultural differences in the ability to enhance central-parietal LPP responses for both positively and negativelyvalenced stimuli, and the ability to enhance these two types of responses was positively correlated for Americans but negatively for East Asians. These results are consistent with the notion that cultural variations in norms and values regarding affective expression and experiences shape how the brain regulates emotions.

  5. Enhancing the Benefits of Written Emotional Disclosure through Response Training

    OpenAIRE

    Konig, Andrea; Eonta, Alison; Dyal, Stephanie R.; Vrana, Scott R.

    2013-01-01

    Writing about a personal stressful event has been found to have psychological and physical health benefits, especially when physiological response increases during writing. Response training was developed to amplify appropriate physiological reactivity in imagery exposure. The present study examined whether response training enhances the benefits of written emotional disclosure. Participants were assigned to either a written emotional disclosure condition (n = 113) or a neutral writing condit...

  6. Contrast-enhanced Spectral Mammography: Modality-Specific Artifacts and Other Factors Which May Interfere with Image Quality.

    Science.gov (United States)

    Bhimani, Chandni; Li, Luna; Liao, Lydia; Roth, Robyn G; Tinney, Elizabeth; Germaine, Pauline

    2017-01-01

    Contrast-enhanced spectral mammography (CESM) uses full field digital mammography with the added benefit of intravenous contrast administration to significantly reduce false-positive and false-negative results and improve specificity while maintaining high sensitivity. For CESM to fulfill its purpose, one should be aware of possible artifacts and other factors which may interfere with image quality, and attention should be taken to minimize these factors. This pictorial demonstration will depict types of artifacts detected and other factors that interfere with image acquisition in our practice since CESM implementation. Many of the artifacts and other factors we have encountered while using CESM have simple solutions to resolve them. The illustrated artifacts and other factors interfering with image quality will serve as a useful reference to anyone using CESM. Copyright © 2017 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved.

  7. Spectral Kernel Approach to Study Radiative Response of Climate Variables and Interannual Variability of Reflected Solar Spectrum

    Science.gov (United States)

    Jin, Zhonghai; Wielicki, Bruce A.; Loukachine, Constantin; Charlock, Thomas P.; Young, David; Noeel, Stefan

    2011-01-01

    The radiative kernel approach provides a simple way to separate the radiative response to different climate parameters and to decompose the feedback into radiative and climate response components. Using CERES/MODIS/Geostationary data, we calculated and analyzed the solar spectral reflectance kernels for various climate parameters on zonal, regional, and global spatial scales. The kernel linearity is tested. Errors in the kernel due to nonlinearity can vary strongly depending on climate parameter, wavelength, surface, and solar elevation; they are large in some absorption bands for some parameters but are negligible in most conditions. The spectral kernels are used to calculate the radiative responses to different climate parameter changes in different latitudes. The results show that the radiative response in high latitudes is sensitive to the coverage of snow and sea ice. The radiative response in low latitudes is contributed mainly by cloud property changes, especially cloud fraction and optical depth. The large cloud height effect is confined to absorption bands, while the cloud particle size effect is found mainly in the near infrared. The kernel approach, which is based on calculations using CERES retrievals, is then tested by direct comparison with spectral measurements from Scanning Imaging Absorption Spectrometer for Atmospheric Cartography (SCIAMACHY) (a different instrument on a different spacecraft). The monthly mean interannual variability of spectral reflectance based on the kernel technique is consistent with satellite observations over the ocean, but not over land, where both model and data have large uncertainty. RMS errors in kernel ]derived monthly global mean reflectance over the ocean compared to observations are about 0.001, and the sampling error is likely a major component.

  8. The Fly Sensitizing Pigment Enhances UV Spectral Sensitivity While Preventing Polarization-Induced Artifacts

    Directory of Open Access Journals (Sweden)

    Marko Ilić

    2018-02-01

    Full Text Available Microvillar photoreceptors are intrinsically capable of detecting the orientation of e-vector of linearly polarized light. They provide most invertebrates with an additional sensory channel to detect important features of their visual environment. However, polarization sensitivity (PS of photoreceptors may lead to the detection of polarization-induced false colors and intensity contrasts. Most insect photoreceptors are thus adapted to have minimal PS. Flies have twisted rhabdomeres with microvilli rotated along the length of the ommatidia to reduce PS. The additional UV-absorbing sensitizing pigment on their opsin minimizes PS in the ultraviolet. We recorded voltage from Drosophila photoreceptors R1–6 to measure the spectral dependence of PS and found that PS in the UV is invariably negligible but can be substantial above 400 nm. Using modeling, we demonstrate that in R1–6 without the sensitizing pigment, PS in the UV (PSUV would exceed PS in the visible part of the spectrum (PSVIS by a factor PSUV/PSVIS = 1.2–1.8, as lower absorption of Rh1 rhodopsin reduces self-screening. We use polarimetric imaging of objects relevant to fly polarization vision to show that their degree of polarization outdoors is highest in the short-wavelength part of the spectrum. Thus, under natural illumination, the sensitizing pigment in R1–6 renders even those cells with high PS in the visible part unsuitable for proper polarization vision. We assume that fly ventral polarization vision can be mediated by R7 alone, with R1–6 serving as an unpolarized reference channel.

  9. The tumour border on contrast-enhanced spectral mammography and its relation to histological characteristics of invasive breast cancer.

    Science.gov (United States)

    Ambicka, Aleksandra; Luczynska, Elzbieta; Adamczyk, Agnieszka; Harazin-Lechowska, Agnieszka; Sas-Korczynska, Beata; Niemiec, Joanna

    Contrast-enhanced spectral mammography (CESM) is one of the new diagnostic modalities implemented in clinical practice. In the case of these techniques, there are two major issues to be addressed: (1) their diagnostic usefulness, and (2) the relation between parameters assessed using these techniques and well-known diagnostic/prognostic/predictive markers (histological, clinical, and molecular). Therefore, we studied the relationship between the tumour margin assessed on CESM and (1) tumour borders defined on the basis of macroscopic and microscopic examination, (2) pT, (3) pN, and (4) tumour grade in a group of 82 breast cancer patients. Based on CESM, the tumour border was defined as sharp, indistinct or spiculated, whereas in the case of lesions showing weak or medium enhancement on CESM the borders were classified as unspecified. We found a statistically significant relationship between tumour margin on CESM and (1) macroscopic border (a spiculated margin on CESM was found only in carcinomas with an invasive border on histological examination; p = 0.004), (2) pT (p = 0.016), and (3) pN (nodal involvement was observed most frequently in carcinomas with a spiculated or indistinct margin on CESM; p = 0.045). Moreover, in cases with an undefined margin on CESM (cases showing weak or medium enhancement on CESM), both invasive and pushing borders were found on histological examination. The results of our preliminary study suggest that it is possible to assess macroscopic borders of examined lesions on the basis of CESM imaging. This might be useful in planning the extent of surgical excision. On the other hand, the assessment of the tumour margin on CESM might not be precise in cases showing weak enhancement.

  10. The tumour border on contrast-enhanced spectral mammography and its relation to histological characteristics of invasive breast cancer

    Directory of Open Access Journals (Sweden)

    Aleksandra Ambicka

    2016-11-01

    Full Text Available Contrast-enhanced spectral mammography (CESM is one of the new diagnostic modalities implemented in clinical practice. In the case of these techniques, there are two major issues to be addressed: (1 their diagnostic usefulness, and (2 the relation between parameters assessed using these techniques and well-known diagnostic/prognostic/predictive markers (histological, clinical, and molecular. Therefore, we studied the relationship between the tumour margin assessed on CESM and (1 tumour borders defined on the basis of macroscopic and microscopic examination, (2 pT, (3 pN, and (4 tumour grade in a group of 82 breast cancer patients. Based on CESM, the tumour border was defined as sharp, indistinct or spiculated, whereas in the case of lesions showing weak or medium enhancement on CESM the borders were classified as unspecified. We found a statistically significant relationship between tumour margin on CESM and (1 macroscopic border (a spiculated margin on CESM was found only in carcinomas with an invasive border on histological examination; p = 0.004, (2 pT (p = 0.016, and (3 pN (nodal involvement was observed most frequently in carcinomas with a spiculated or indistinct margin on CESM; p = 0.045. Moreover, in cases with an undefined margin on CESM (cases showing weak or medium enhancement on CESM, both invasive and pushing borders were found on histological examination. The results of our preliminary study suggest that it is possible to assess macroscopic borders of examined lesions on the basis of CESM imaging. This might be useful in planning the extent of surgical excision. On the other hand, the assessment of the tumour margin on CESM might not be precise in cases showing weak enhancement.

  11. Enhanced terahertz magnetic dipole response by subwavelength fiber

    DEFF Research Database (Denmark)

    Atakaramians, Shaghik; Shadrivov, Ilya V.; Miroshnichenko, Andrey E.

    2018-01-01

    Dielectric sub-wavelength particles have opened up a new platform for realization of magnetic light. Recently, we have demonstrated that a dipole emitter by a sub-wavelength fiber leads to an enhanced magnetic response. Here, we experimentally demonstrate an enhanced magnetic dipole source......-fiber system excited by a magnetic source. This coupled magnetic dipole and optical fiber system can be considered a unit cell of metasurfaces for manipulation of terahertz radiation and is a proof-of-concept of a possibility to achieve enhanced radiation of a dipole source in proximity of a sub...

  12. Development of spectral history methods for pin-by-pin core analysis method using three-dimensional direct response matrix

    International Nuclear Information System (INIS)

    Mitsuyasu, T.; Ishii, K.; Hino, T.; Aoyama, M.

    2009-01-01

    Spectral history methods for pin-by-pin core analysis method using the three-dimensional direct response matrix have been developed. The direct response matrix is formalized by four sub-response matrices in order to respond to a core eigenvalue k and thus can be recomposed at each outer iteration in the core analysis. For core analysis, it is necessary to take into account the burn-up effect related to spectral history. One of the methods is to evaluate the nodal burn-up spectrum obtained using the out-going neutron current. The other is to correct the fuel rod neutron production rates obtained the pin-by-pin correction. These spectral history methods were tested in a heterogeneous system. The test results show that the neutron multiplication factor error can be reduced by half during burn-up, the nodal neutron production rates errors can be reduced by 30% or more. The root-mean-square differences between the relative fuel rod neutron production rate distributions can be reduced within 1.1% error. This means that these methods can accurately reflect the effects of intra- and inter-assembly heterogeneities during burn-up and can be used for core analysis. Core analysis with the DRM method was carried out for an ABWR quarter core and it was found that both thermal power and coolant-flow distributions were smoothly converged. (authors)

  13. Development of a very fast spectral response measurement system for analysis of hydrogenated amorphous silicon solar cells and modules

    International Nuclear Information System (INIS)

    Rodríguez, J.A.; Fortes, M.; Alberte, C.; Vetter, M.; Andreu, J.

    2013-01-01

    Highlights: ► Spectral response equipment for measuring a-Si:H solar cells in a few seconds. ► Equipment based on 16 LEDs with simultaneous illumination of the solar cell. ► The current generated by each LED is analyzed by a Fast Fourier Transform. ► Cheap equipment without lock-in technology for the current measurement. ► Measurement error vs. conventional measurement less than 1% in J sc . - Abstract: An important requirement for a very fast spectral response measurement system is the simultaneous illumination of the solar cell at multiple well defined wavelengths. Nowadays this can be done by means of light emitting diodes (LEDs) available for a multitude of wavelengths. For the purpose to measure the spectral response (SR) of amorphous silicon solar cells a detailed characterization of LEDs emitting in the wavelength range from 300 nm to 800 nm was performed. In the here developed equipment the LED illumination is modulated in the frequency range from 100 Hz to 200 Hz and the current generated by each LED is analyzed by a Fast Fourier Transform (FFT) to determine the current component corresponding to each wavelength. The equipment provides a signal to noise ratio of 2–4 orders of magnitude for individual wavelengths resulting in a precise measurement of the SR over the whole wavelength range. The difference of the short circuit current determined from the SR is less than 1% in comparison to a conventional system with monochromator.

  14. Enhanced Responsivity of Photodetectors Realized via Impact Ionization

    Directory of Open Access Journals (Sweden)

    De-Zhen Shen

    2012-01-01

    Full Text Available To increase the responsivity is one of the vital issues for a photodetector. By employing ZnO as a representative material of ultraviolet photodetectors and Si as a representative material of visible photodetectors, an impact ionization process, in which additional carriers can be generated in an insulating layer at a relatively large electric field, has been employed to increase the responsivity of a semiconductor photodetector. It is found that the responsivity of the photodetectors can be enhanced by tens of times via this impact ionization process. The results reported in this paper provide a general route to enhance the responsivity of a photodetector, thus may represent a step towards high-performance photodetectors.

  15. Monte Carlo modelling of a-Si EPID response: The effect of spectral variations with field size and position

    International Nuclear Information System (INIS)

    Parent, Laure; Seco, Joao; Evans, Phil M.; Fielding, Andrew; Dance, David R.

    2006-01-01

    This study focused on predicting the electronic portal imaging device (EPID) image of intensity modulated radiation treatment (IMRT) fields in the absence of attenuation material in the beam with Monte Carlo methods. As IMRT treatments consist of a series of segments of various sizes that are not always delivered on the central axis, large spectral variations may be observed between the segments. The effect of these spectral variations on the EPID response was studied with fields of various sizes and off-axis positions. A detailed description of the EPID was implemented in a Monte Carlo model. The EPID model was validated by comparing the EPID output factors for field sizes between 1x1 and 26x26 cm 2 at the isocenter. The Monte Carlo simulations agreed with the measurements to within 1.5%. The Monte Carlo model succeeded in predicting the EPID response at the center of the fields of various sizes and offsets to within 1% of the measurements. Large variations (up to 29%) of the EPID response were observed between the various offsets. The EPID response increased with field size and with field offset for most cases. The Monte Carlo model was then used to predict the image of a simple test IMRT field delivered on the beam axis and with an offset. A variation of EPID response up to 28% was found between the on- and off-axis delivery. Finally, two clinical IMRT fields were simulated and compared to the measurements. For all IMRT fields, simulations and measurements agreed within 3%--0.2 cm for 98% of the pixels. The spectral variations were quantified by extracting from the spectra at the center of the fields the total photon yield (Y total ), the photon yield below 1 MeV (Y low ), and the percentage of photons below 1 MeV (P low ). For the studied cases, a correlation was shown between the EPID response variation and Y total , Y low , and P low

  16. Extracting the noise spectral densities parameters of JFET transistor by modeling a nuclear electronics channel response

    International Nuclear Information System (INIS)

    Assaf, J.

    2009-07-01

    Mathematical model for the RMS noise of JFET transistor has been realized. Fitting the model according to the experimental results gives the noise spectral densities values. Best fitting was for the model of three noise sources and real preamplifier transfer function. After gamma irradiation, an additional and important noise sources appeared and two point defects are estimated through the fitting process. (author)

  17. Dual-Energy Contrast-Enhanced Spectral Mammography: Enhancement Analysis on BI-RADS 4 Non-Mass Microcalcifications in Screened Women.

    Directory of Open Access Journals (Sweden)

    Yun-Chung Cheung

    Full Text Available Mammography screening is a cost-efficient modality with high sensitivity for detecting impalpable cancer with microcalcifications, and results in reduced mortality rates. However, the probability of finding microcalcifications without associated cancerous masses varies. We retrospectively evaluated the diagnosis and cancer probability of the non-mass screened microcalcifications by dual-energy contrast-enhanced spectral mammography (DE-CESM.With ethical approval from our hospital, we enrolled the cases of DE-CESM for analysis under the following inclusion criteria: (1 referrals due to screened BI-RADS 4 microcalcifications; (2 having DE-CESM prior to stereotactic biopsy; (3 no associated mass found by sonography and physical examination; and (4 pathology-based diagnosis using stereotactic vacuum-assisted breast biopsy. We analyzed the added value of post-contrast enhancement on DE-CESM.A total of 94 biopsed lesions were available for analysis in our 87 women, yielding 27 cancers [19 ductal carcinoma in situ (DCIS, and 8 invasive ductal carcinoma (IDC], 32 pre-malignant and 35 benign lesions. Of these 94 lesions, 33 showed associated enhancement in DE-CESM while the other 61 did not. All 8 IDC (100% and 16 of 19 DCIS (84.21% showed enhancement, but the other 3 DCIS (15.79% did not. Overall sensitivity, specificity, positive predictive value, negative predictive value and accuracy were 88.89%, 86.56%, 72.72%, 95.08% and 87.24%, respectively. The performances of DE-CESM on both amorphous and pleomorphic microcalcifications were satisfactory (AUC 0.8 and 0.92, respectively. The pleomorphous microcalcifications with enhancement showed higher positive predictive value (90.00% vs 46.15%, p = 0.013 and higher cancer probability than the amorphous microcalcifications (46.3% VS 15.1%. The Odds Ratio was 4.85 (95% CI: 1.84-12.82.DE-CESM might provide added value in assessing the non-mass screened breast microcalcification, with enhancement favorable to the

  18. Dual-Energy Contrast-Enhanced Spectral Mammography: Enhancement Analysis on BI-RADS 4 Non-Mass Microcalcifications in Screened Women.

    Science.gov (United States)

    Cheung, Yun-Chung; Juan, Yu-Hsiang; Lin, Yu-Ching; Lo, Yung-Feng; Tsai, Hsiu-Pei; Ueng, Shir-Hwa; Chen, Shin-Cheh

    2016-01-01

    Mammography screening is a cost-efficient modality with high sensitivity for detecting impalpable cancer with microcalcifications, and results in reduced mortality rates. However, the probability of finding microcalcifications without associated cancerous masses varies. We retrospectively evaluated the diagnosis and cancer probability of the non-mass screened microcalcifications by dual-energy contrast-enhanced spectral mammography (DE-CESM). With ethical approval from our hospital, we enrolled the cases of DE-CESM for analysis under the following inclusion criteria: (1) referrals due to screened BI-RADS 4 microcalcifications; (2) having DE-CESM prior to stereotactic biopsy; (3) no associated mass found by sonography and physical examination; and (4) pathology-based diagnosis using stereotactic vacuum-assisted breast biopsy. We analyzed the added value of post-contrast enhancement on DE-CESM. A total of 94 biopsed lesions were available for analysis in our 87 women, yielding 27 cancers [19 ductal carcinoma in situ (DCIS), and 8 invasive ductal carcinoma (IDC)], 32 pre-malignant and 35 benign lesions. Of these 94 lesions, 33 showed associated enhancement in DE-CESM while the other 61 did not. All 8 IDC (100%) and 16 of 19 DCIS (84.21%) showed enhancement, but the other 3 DCIS (15.79%) did not. Overall sensitivity, specificity, positive predictive value, negative predictive value and accuracy were 88.89%, 86.56%, 72.72%, 95.08% and 87.24%, respectively. The performances of DE-CESM on both amorphous and pleomorphic microcalcifications were satisfactory (AUC 0.8 and 0.92, respectively). The pleomorphous microcalcifications with enhancement showed higher positive predictive value (90.00% vs 46.15%, p = 0.013) and higher cancer probability than the amorphous microcalcifications (46.3% VS 15.1%). The Odds Ratio was 4.85 (95% CI: 1.84-12.82). DE-CESM might provide added value in assessing the non-mass screened breast microcalcification, with enhancement favorable to the

  19. MO-E-217A-01: Contrast-Enhanced Spectral Mammography - Physical Aspects and QA.

    Science.gov (United States)

    Yaffe, M; Hill, M

    2012-06-01

    To describe the current state of dual energy contrast-enhanced digital mammography, to discuss those aspects of its operation that require evaluation or monitoring and to propose elements of a program for quality assurance of such systems. The principles of dual-energy contrast imaging will be discussed and tools and techniques for assessment of performance will be described. Many of the elements affecting image quality and dose performance in digital mammography (eg noise, system linearity, consistency of x-ray output and detector performance, artifacts) remain important. In addition, the ability to register images can influence the resultant image quality. The maintenance of breast compression thickness during the imaging procedure and calibration of the system to allow quantification of iodine in the breast represent new challenges to quality assurance. CESM provides a means of acquiring new information regarding tumor angiogenesis and may reveal some cancers that will not be detectable on digital mammography. It may also better demonstrate the extent of disease. The medical physicist must understand the dependence of image quality on physical factors. Implementation of a relevant QA program will be required if the promise of this new modality is to be delivered. © 2012 American Association of Physicists in Medicine.

  20. Enhanced spectral resolution by high-dimensional NMR using the filter diagonalization method and "hidden" dimensions.

    Science.gov (United States)

    Meng, Xi; Nguyen, Bao D; Ridge, Clark; Shaka, A J

    2009-01-01

    High-dimensional (HD) NMR spectra have poorer digital resolution than low-dimensional (LD) spectra, for a fixed amount of experiment time. This has led to "reduced-dimensionality" strategies, in which several LD projections of the HD NMR spectrum are acquired, each with higher digital resolution; an approximate HD spectrum is then inferred by some means. We propose a strategy that moves in the opposite direction, by adding more time dimensions to increase the information content of the data set, even if only a very sparse time grid is used in each dimension. The full HD time-domain data can be analyzed by the filter diagonalization method (FDM), yielding very narrow resonances along all of the frequency axes, even those with sparse sampling. Integrating over the added dimensions of HD FDM NMR spectra reconstitutes LD spectra with enhanced resolution, often more quickly than direct acquisition of the LD spectrum with a larger number of grid points in each of the fewer dimensions. If the extra-dimensions do not appear in the final spectrum, and are used solely to boost information content, we propose the moniker hidden-dimension NMR. This work shows that HD peaks have unmistakable frequency signatures that can be detected as single HD objects by an appropriate algorithm, even though their patterns would be tricky for a human operator to visualize or recognize, and even if digital resolution in an HD FT spectrum is very coarse compared with natural line widths.

  1. Spectrally enhanced imaging of occlusal surfaces and artificial shallow enamel erosions with a scanning fiber endoscope

    Science.gov (United States)

    Zhang, Liang; Nelson, Leonard Y.; Seibel, Eric J.

    2012-07-01

    An ultrathin scanning fiber endoscope, originally developed for cancer diagnosis, was used to image dental occlusal surfaces as well as shallow artificially induced enamel erosions from human extracted teeth (n=40). Enhanced image resolution of occlusal surfaces was obtained using a short-wavelength 405-nm illumination laser. In addition, artificial erosions of varying depths were also imaged with 405-, 404-, 532-, and 635-nm illumination lasers. Laser-induced autofluorescence images of the teeth using 405-nm illumination were also obtained. Contrast between sound and eroded enamel was quantitatively computed for each imaging modality. For shallow erosions, the image contrast with respect to sound enamel was greatest for the 405-nm reflected image. It was also determined that the increased contrast was in large part due to volume scattering with a smaller component from surface scattering. Furthermore, images obtained with a shallow penetration depth illumination laser (405 nm) provided the greatest detail of surface enamel topography since the reflected light does not contain contributions from light reflected from greater depths within the enamel tissue. Multilayered Monte Carlo simulations were also performed to confirm the experimental results.

  2. Dual-energy approach to contrast-enhanced mammography using the balanced filter method: spectral optimization and preliminary phantom measurement.

    Science.gov (United States)

    Saito, Masatoshi

    2007-11-01

    Dual-energy contrast agent-enhanced mammography is a technique of demonstrating breast cancers obscured by a cluttered background resulting from the contrast between soft tissues in the breast. The technique has usually been implemented by exploiting two exposures to different x-ray tube voltages. In this article, another dual-energy approach using the balanced filter method without switching the tube voltages is described. For the spectral optimization of dual-energy mammography using the balanced filters, we applied a theoretical framework reported by Lemacks et al. [Med. Phys. 29, 1739-1751 (2002)] to calculate the signal-to-noise ratio (SNR) in an iodinated contrast agent subtraction image. This permits the selection of beam parameters such as tube voltage and balanced filter material, and the optimization of the latter's thickness with respect to some critical quantity-in this case, mean glandular dose. For an imaging system with a 0.1 mm thick CsI:T1 scintillator, we predict that the optimal tube voltage would be 45 kVp for a tungsten anode using zirconium, iodine, and neodymium balanced filters. A mean glandular dose of 1.0 mGy is required to obtain an SNR of 5 in order to detect 1.0 mg/cm2 iodine in the resulting clutter-free image of a 5 cm thick breast composed of 50% adipose and 50% glandular tissue. In addition to spectral optimization, we carried out phantom measurements to demonstrate the present dual-energy approach for obtaining a clutter-free image, which preferentially shows iodine, of a breast phantom comprising three major components-acrylic spheres, olive oil, and an iodinated contrast agent. The detection of iodine details on the cluttered background originating from the contrast between acrylic spheres and olive oil is analogous to the task of distinguishing contrast agents in a mixture of glandular and adipose tissues.

  3. Dual-energy approach to contrast-enhanced mammography using the balanced filter method: Spectral optimization and preliminary phantom measurement

    International Nuclear Information System (INIS)

    Saito, Masatoshi

    2007-01-01

    Dual-energy contrast agent-enhanced mammography is a technique of demonstrating breast cancers obscured by a cluttered background resulting from the contrast between soft tissues in the breast. The technique has usually been implemented by exploiting two exposures to different x-ray tube voltages. In this article, another dual-energy approach using the balanced filter method without switching the tube voltages is described. For the spectral optimization of dual-energy mammography using the balanced filters, we applied a theoretical framework reported by Lemacks et al. [Med. Phys. 29, 1739-1751 (2002)] to calculate the signal-to-noise ratio (SNR) in an iodinated contrast agent subtraction image. This permits the selection of beam parameters such as tube voltage and balanced filter material, and the optimization of the latter's thickness with respect to some critical quantity--in this case, mean glandular dose. For an imaging system with a 0.1 mm thick CsI:Tl scintillator, we predict that the optimal tube voltage would be 45 kVp for a tungsten anode using zirconium, iodine, and neodymium balanced filters. A mean glandular dose of 1.0 mGy is required to obtain an SNR of 5 in order to detect 1.0 mg/cm 2 iodine in the resulting clutter-free image of a 5 cm thick breast composed of 50% adipose and 50% glandular tissue. In addition to spectral optimization, we carried out phantom measurements to demonstrate the present dual-energy approach for obtaining a clutter-free image, which preferentially shows iodine, of a breast phantom comprising three major components - acrylic spheres, olive oil, and an iodinated contrast agent. The detection of iodine details on the cluttered background originating from the contrast between acrylic spheres and olive oil is analogous to the task of distinguishing contrast agents in a mixture of glandular and adipose tissues

  4. Enhancement by platelets of oxygen radical responses of human neutrophils

    Energy Technology Data Exchange (ETDEWEB)

    McCulloch, K.K.; Powell, J.; Johnson, K.J.; Ward, P.A.

    1986-03-01

    When human blood neutrophils were incubated with immune complexes (consisting of IgG antibody) in the presence of platelets, there was a 2 to 10 fold enhancement in the generation of O-/sub 2/ and H/sub 2/O/sub 2/. This enhancement phenomenon was proportional to the dose of immune complex added and the number of platelets present. The response was not agonist specific since similar enhancement also occurred with the following agonists: phorbol myristate acetate, opsonized zymosan particles and the chemotactic peptide N-formyl-met-leu-phe. The platelet related phenomenon of enhanced O-/sub 2/ generation could not be reproduced by the addition of serotonin, histamine or platelet-derived growth factor and was not affected by prior treatment of platelets with cyclooxygenase inhibitors (indomethacin, piroxicam) or lipoxygenase inhibitors (nafazatrom, BW755C or nordihydroguaiaretic acid). However, activation of platelets by thrombin caused release into the platelet supernatant fluid of a factor that, only in the presence of immune complexes, caused enhanced O-/sub 2/ responses to neutrophils. These data indicate that platelets potentiate oxygen radical responses of human neutrophils and suggest a mechanisms by which platelets may participate in tissue injury which is mediated by oxygen radical products from activated neutrophils.

  5. Enhancement by platelets of oxygen radical responses of human neutrophils

    International Nuclear Information System (INIS)

    McCulloch, K.K.; Powell, J.; Johnson, K.J.; Ward, P.A.

    1986-01-01

    When human blood neutrophils were incubated with immune complexes (consisting of IgG antibody) in the presence of platelets, there was a 2 to 10 fold enhancement in the generation of O- 2 and H 2 O 2 . This enhancement phenomenon was proportional to the dose of immune complex added and the number of platelets present. The response was not agonist specific since similar enhancement also occurred with the following agonists: phorbol myristate acetate, opsonized zymosan particles and the chemotactic peptide N-formyl-met-leu-phe. The platelet related phenomenon of enhanced O- 2 generation could not be reproduced by the addition of serotonin, histamine or platelet-derived growth factor and was not affected by prior treatment of platelets with cyclooxygenase inhibitors (indomethacin, piroxicam) or lipoxygenase inhibitors (nafazatrom, BW755C or nordihydroguaiaretic acid). However, activation of platelets by thrombin caused release into the platelet supernatant fluid of a factor that, only in the presence of immune complexes, caused enhanced O- 2 responses to neutrophils. These data indicate that platelets potentiate oxygen radical responses of human neutrophils and suggest a mechanisms by which platelets may participate in tissue injury which is mediated by oxygen radical products from activated neutrophils

  6. Will Biomedical Enhancements Undermine Solidarity, Responsibility, Equality and Autonomy?

    Science.gov (United States)

    Lev, Ori

    2009-01-01

    Prominent thinkers such as Jurgen Habermas and Michael Sandel are warning that biomedical enhancements will undermine fundamental political values. Yet, whether biomedical enhancements will undermine such values depends on how biomedical enhancements will function, how they will be administered and to whom. Since only few enhancements are obtainable, it is difficult to tell whether their predictions are sound. Nevertheless, such warnings are extremely valuable. As a society we must, at the very least, be aware of developments that could have harmful consequences. Indeed, if important values would be jeopardized, we should take appropriate measures to protect them. This paper focuses on four central values: solidarity, personal responsibility, equality and autonomy. It delineates the conditions under which biomedical enhancements would undermine these values. It also details the circumstances under which these values would be unaffected by enhancements as well as those under which they would be promoted. Specifying these conditions is valuable; it would enable society to prepare appropriate ethical guidelines and policy responses in advance. PMID:20002073

  7. Enhanced antioxidative responses of a salt-resistant wheat cultivar ...

    African Journals Online (AJOL)

    Enhanced antioxidative responses of a salt-resistant wheat cultivar facilitate its adaptation to salt stress. L Chen, H Yin, J Xu, X Liu. Abstract. Wheat cultivars capable of accumulating minerals under salt stress are of considerable interest for their potential to improve crop productivity and crop quality. This study addressed the ...

  8. Effect of Soil Use and Coverage on the Spectral Response of an Oxisol in the VIS-NIR-MIR Region

    Directory of Open Access Journals (Sweden)

    Javier M. Martín-López

    2017-02-01

    Full Text Available In this study, the spectral responses obtained from a Typic Red Hapludox (oxisol were analyzed under different uses and occupations: Ficus elastica cultivation, Citrus + Arachis association cultivation, transitional crops, forest, Mangifera indica, Anacardium occidentale, Elaeis guineensis (18 years, Brachiaria decumbens, Brachiaria brizantha, and Musa × paradisiaca + Zea mays at the La Libertad Research Center in the department of Meta in Colombia (4°04′ North latitude, 73°30′ West longitude, 330 MAMSL. Sampling was performed with four random replicates of the horizon A and B to determine the contents of organic carbon (CO, pH, exchangeable acidity (Ac. I, cation exchange capacity (Cc, P, Ca, Mg, K, Na, sand, lime, and clay and spectral responses were obtained in the visible band (VIS, near infrared (NIR, and infrared (MIR for each sample under laboratory conditions. A comparison was made between the obtained spectra, determining the main changes in soil properties due to their use and coverage. Variation of soil characteristics such as color, organic carbon content, presence of ferrous compounds, sand, silt, and clay content and mineralogy allow the identification of the main spectral changes of soils, demonstrating the importance of the use of reflectance spectroscopy as a tool of comparison and estimation between physical-chemical properties of the soils.

  9. Agricultural Soil Spectral Response and Properties Assessment: Effects of Measurement Protocol and Data Mining Technique

    Directory of Open Access Journals (Sweden)

    Asa Gholizadeh

    2017-10-01

    Full Text Available Soil spectroscopy has shown to be a fast, cost-effective, environmentally friendly, non-destructive, reproducible and repeatable analytical technique. Soil components, as well as types of instruments, protocols, sampling methods, sample preparation, spectral acquisition techniques and analytical algorithms have a combined influence on the final performance. Therefore, it is important to characterize these differences and to introduce an effective approach in order to minimize the technical factors that alter reflectance spectra and consequent prediction. To quantify this alteration, a joint project between Czech University of Life Sciences Prague (CULS and Tel-Aviv University (TAU was conducted to estimate Cox, pH-H2O, pH-KCl and selected forms of Fe and Mn. Two different soil spectral measurement protocols and two data mining techniques were used to examine seventy-eight soil samples from five agricultural areas in different parts of the Czech Republic. Spectral measurements at both laboratories were made using different ASD spectroradiometers. The CULS protocol was based on employing a contact probe (CP spectral measurement scheme, while the TAU protocol was carried out using a CP measurement method, accompanied with the internal soil standard (ISS procedure. Two spectral datasets, acquired from different protocols, were both analyzed using partial least square regression (PLSR technique as well as the PARACUDA II®, a new data mining engine for optimizing PLSR models. The results showed that spectra based on the CULS setup (non-ISS demonstrated significantly higher albedo intensity and reflectance values relative to the TAU setup with ISS. However, the majority of statistics using the TAU protocol was not noticeably better than the CULS spectra. The paper also highlighted that under both measurement protocols, the PARACUDA II® engine proved to be a powerful tool for providing better results than PLSR. Such initiative is not only a way to

  10. Evaluation of low-energy contrast-enhanced spectral mammography images by comparing them to full-field digital mammography using EUREF image quality criteria

    OpenAIRE

    Lalji, U. C.; Jeukens, C. R. L. P. N.; Houben, I.; Nelemans, P. J.; van Engen, R. E.; van Wylick, E.; Beets-Tan, R. G. H.; Wildberger, J. E.; Paulis, L. E.; Lobbes, M. B. I.

    2015-01-01

    Objective Contrast-enhanced spectral mammography (CESM) examination results in a low-energy (LE) and contrast-enhanced image. The LE appears similar to a full-field digital mammogram (FFDM). Our aim was to evaluate LE CESM image quality by comparing it to FFDM using criteria defined by the European Reference Organization for Quality Assured Breast Screening and Diagnostic Services (EUREF). Methods A total of 147 cases with both FFDM and LE images were independently scored by two experienced r...

  11. Vascular response to ischemia in the feet of falanga torture victims and normal controls--color and spectral Doppler findings

    DEFF Research Database (Denmark)

    Torp-Pedersen, Søren; Amris, Kirstine; Holm, Christian Cato

    2009-01-01

    to controls. On color Doppler this would be seen as less color after ischemia and on spectral Doppler as elevated resistive index (RI). METHODS: Ten male torture victims from the Middle East and nine age, sex and ethnically matched controls underwent Doppler examination of the abductor hallucis and flexor...... digitorum brevis muscles before and after two minutes ischemia induced with a pressure cuff over the malleoli. The color Doppler findings were quantified with the color fraction (CF) before and after ischemia. On spectral Doppler the resistive index was measured once before and three consecutive times after....... However, the trend in RI still supports the hypothesis. The negative findings may be due to inadequate design where the CF and RI were measured in one setting, perhaps resulting in both methods being applied imperfectly. The response to ischemia seems short-lived and we suggest that the Doppler methods...

  12. Contrast-enhanced spectral mammography in recalls from the Dutch breast cancer screening program : validation of results in a large multireader, multicase study

    NARCIS (Netherlands)

    Lalji, U C; Houben, I P L; Prevos, R; Gommers, S; van Goethem, M; Vanwetswinkel, S; Pijnappel, R; Steeman, R; Frotscher, C; Mok, W; Nelemans, P; Smidt, M L; Beets-Tan, R G; Wildberger, J E; Lobbes, M B I

    2016-01-01

    OBJECTIVES: Contrast-enhanced spectral mammography (CESM) is a promising problem-solving tool in women referred from a breast cancer screening program. We aimed to study the validity of preliminary results of CESM using a larger panel of radiologists with different levels of CESM experience.

  13. Immunomodulator-based enhancement of anti smallpox immune responses.

    Science.gov (United States)

    Martínez, Osmarie; Miranda, Eric; Ramírez, Maite; Santos, Saritza; Rivera, Carlos; Vázquez, Luis; Sánchez, Tomás; Tremblay, Raymond L; Ríos-Olivares, Eddy; Otero, Miguel

    2015-01-01

    The current live vaccinia virus vaccine used in the prevention of smallpox is contraindicated for millions of immune-compromised individuals. Although vaccination with the current smallpox vaccine produces protective immunity, it might result in mild to serious health complications for some vaccinees. Thus, there is a critical need for the production of a safe virus-free vaccine against smallpox that is available to everyone. For that reason, we investigated the impact of imiquimod and resiquimod (Toll-like receptors agonists), and the codon-usage optimization of the vaccinia virus A27L gene in the enhancement of the immune response, with intent of producing a safe, virus-free DNA vaccine coding for the A27 vaccinia virus protein. We analyzed the cellular-immune response by measuring the IFN-γ production of splenocytes by ELISPOT, the humoral-immune responses measuring total IgG and IgG2a/IgG1 ratios by ELISA, and the TH1 and TH2 cytokine profiles by ELISA, in mice immunized with our vaccine formulation. The proposed vaccine formulation enhanced the A27L vaccine-mediated production of IFN-γ on mouse spleens, and increased the humoral immunity with a TH1-biased response. Also, our vaccine induced a TH1 cytokine milieu, which is important against viral infections. These results support the efforts to find a new mechanism to enhance an immune response against smallpox, through the implementation of a safe, virus-free DNA vaccination platform.

  14. The effect of spectral filters on VEP and alpha-wave responses

    Directory of Open Access Journals (Sweden)

    Kevin T. Willeford

    2016-04-01

    Conclusions: The Intuitive Colorimeter filters significantly increased both N75 and P100 latencies, an effect which is primarily attributable (∼75% to luminance, and in some cases, specific spectral effects (e.g., blue and red. VEP amplitude and alpha power were not significantly affected. These findings provide an important reference to which either amplitude or power changes in light-sensitive, younger clinical groups can be compared.

  15. The effect of organic contaminants on the spectral induced polarization response of porous media - mechanistic approach

    Science.gov (United States)

    Schwartz, N.; Huisman, J. A.; Furman, A.

    2012-12-01

    In recent years, there is a growing interest in using geophysical methods in general and spectral induced polarization (SIP) in particular as a tool to detect and monitor organic contaminants within the subsurface. The general idea of the SIP method is to inject alternating current through a soil volume and to measure the resultant potential in order to obtain the relevant soil electrical properties (e.g. complex impedance, complex conductivity/resistivity). Currently, a complete mechanistic understanding of the effect of organic contaminants on the SIP response of soil is still absent. In this work, we combine laboratory experiments with modeling to reveal the main processes affecting the SIP signature of soil contaminated with organic pollutant. In a first set of experiments, we investigate the effect of non-aqueous phase liquids (NAPL) on the complex conductivity of unsaturated porous media. Our results show that addition of NAPL to the porous media increases the real component of the soil electrical conductivity and decreases the polarization of the soil (imaginary component of the complex conductivity). Furthermore, addition of NAPL to the soil resulted in an increase of the electrical conductivity of the soil solution. Based on these results, we suggest that adsorption of NAPL to the soil surface, and exchange process between polar organic compounds in the NAPL and inorganic ions in the soil are the main processes affecting the SIP signature of the contaminated soil. To further support our hypothesis, the temporal change of the SIP signature of a soil as function of a single organic cation concentration was measured. In addition to the measurements of the soil electrical properties, we also measured the effect of the organic cation on the chemical composition of both the bulk and the surface of the soil. The results of those experiments again showed that the electrical conductivity of the soil increased with increasing contaminant concentration. In addition

  16. Silicon spectral response extension through single wall carbon nanotubes in hybrid solar cells

    KAUST Repository

    Del Gobbo, Silvano; Castrucci, P.; Fedele, S.; Riele, L.; Convertino, A.; Morbidoni, M.; De Nicola, F.; Scarselli, M.; Camilli, L.; De Crescenzi, M.

    2013-01-01

    Photovoltaic devices based on single wall carbon nanotubes (SWCNTs) and n-silicon multiple heterojunctions have been fabricated by a SWCNT film transferring process. We report on the ability of the carbon nanotubes to extend the Si spectral range towards the near ultraviolet (UV) and the near infrared regions. Semiconducting and about metallic SWCNT networks have been studied as a function of the film sheet resistance, Rsh. Optical absorbance and Raman spectroscopy have been used to assign nanotube chirality and electronic character. This gave us hints of evidence of the participation of the metal nanotubes in the photocurrent generation. Moreover, we provide evidence that the external quantum efficiency spectral range can be modulated as a function of the SWCNT network sheet resistance in a hybrid SWCNT/Si solar cell. This result will be very useful to further design/optimize devices with improved performance in spectral regions generally not covered by conventional Si p-n devices. © 2013 The Royal Society of Chemistry.

  17. Assessment of arterially hyper-enhancing liver lesions using virtual monoenergetic images from spectral detector CT: phantom and patient experience.

    Science.gov (United States)

    Große Hokamp, N; Höink, A J; Doerner, J; Jordan, D W; Pahn, G; Persigehl, T; Maintz, D; Haneder, S

    2017-11-28

    To investigate a benefit from virtual monoenergetic reconstructions (VMIs) for assessment of arterially hyper-enhancing liver lesions in phantom and patients and to compare hybrid-iterative and spectral image reconstructions of conventional images (CI-IR and CI-SR). All imaging was performed on a SDCT (Philips Healthcare, Best, The Netherlands). Images of a non-anthropomorphic phantom with a lesion-mimicking insert (containing iodine in water solution) and arterial-phase images from contrast-enhanced patient examinations were evaluated. VMIs (40-200 keV, 10 keV increment), CI-IR, and CI-SR were reconstructed using different strengths of image denoising. ROIs were placed in lesions, liver/matrix, muscle; signal-to-noise, contrast-to-noise, and lesion-to-liver ratios (SNR, CNR, and LLR) were calculated. Qualitatively, 40, 70, and 110 keV and CI images were assessed by two radiologists on five-point Likert scales regarding overall image quality, lesion assessment, and noise. In phantoms, SNR was increased threefold by VMI 40keV compared with CI-IR/SR (5.8 ± 1.1 vs. 18.8 ± 2.2, p ≤ 0.001), while no difference was found between CI-IR and CI-SR (p = 1). Denoising was capable of noise reduction by 40%. In total, 20 patients exhibiting 51 liver lesions were assessed. Attenuation was the highest in VMI 40keV , while image noise was comparable to CI-IR resulting in a threefold increase of CNR/LLR (CI-IR 1.3 ± 0.8/4.4 ± 2.0, VMI 40keV : 3.8 ± 2.7/14.2 ± 7.5, p ≤ 0.001). Subjective lesion delineation was the best in VMI 40keV image (p ≤ 0.01), which also provided the lowest perceptible noise and the best overall image quality. VMIs improve assessment of arterially hyper-enhancing liver lesions since they increase lesion contrast while maintaining low image noise throughout the entire keV spectrum. These data suggest that to consider VMI screening after arterially hyper-enhancing liver lesions.

  18. Comparison of the Mammography, Contrast-Enhanced Spectral Mammography and Ultrasonography in a Group of 116 patients.

    Science.gov (United States)

    Luczyńska, Elzbieta; Heinze, Sylwia; Adamczyk, Agnieszka; Rys, Janusz; Mitus, Jerzy W; Hendrick, Edward

    2016-08-01

    Mammography (MG) is the gold-standard in breast cancer detection - the only method documented to reduce breast cancer mortality. Breast ultrasound (US) has been shown to increase sensitivity to breast cancers in screening women with dense breasts. Contrast-enhanced spectral mammography (CESM) is a novel technique intensively developed in the last few years. The goal of this study was to compare the sensitivity, specificity and accuracy of MG, US and CESM in detecting malignant breast lesions. The study included 116 patients. All patients were symptomatic and underwent MG, US and CESM. A radiologist with 20 years of experience in US and MG breast imaging and 1 year of experience in CESM reviewed images acquired in each of the three modalities separately, within an interval of 14-30 days. All identified lesions were confirmed at core biopsy. BI-RADS classifications on US, MG and CESM were compared to histopathology. MG, CESM and US were compared among 116 patients with 137 lesions encountered. Sensitivity of CESM was 100%, significantly higher than that of MG (90%, p<0.004) or US (92%, p<0.01). CESM accuracy was 78%, also higher than MG (69%, p<0.004) and US (70%, p=0.03). There was no statistically significant difference between AUCs for CESM and US (both 0.83). The AUCs of both US and CESM, however, were significantly larger than that of MG (p<0.0004 for each). CESM permitted better detection of malignant lesions than both MG and US, read individually. CESM found lesion enhancement in some benign lesions, as well, yielding a rate of false-positive diagnoses similar to that of MG and US. Copyright© 2016 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

  19. Flexible Spectral Imaging Color Enhancement and Probe-based Confocal Laser Endomicroscopy in Minimal Change Esophageal Reflux Disease.

    Science.gov (United States)

    Pittayanon, Rapat; Aumkaew, Surasak; Rerknimitr, Rungsun; Wisedopas, Naruemon; Kullavanijaya, Pinit

    2016-07-25

    Although flexible spectral imaging color enhancement (FICE) can facilitate the diagnosis of minimal change esophageal reflux disease (MERD), the complicated diagnostic criteria cause suboptimal inter-observer agreement. Confocal laser endomicroscopy (CLE) yields good diagnostic results but its inter-observer agreement has never been explored. This study compares the diagnostic value of magnifying FICE and probe-based CLE (pCLE) for MERD and evaluates the inter-observer agreement of both techniques. Thirty-six patients with suspected MERD and 18 asymptomatic controls were recruited. Magnifying FICE was used for evaluation of distal esophagus. pCLE counted the number of intrapapillary capillary loops (IPCLs) using more than five IPCLs in 500×500 micron area as a criterion for MERD diagnosis. The validity scores and interobserever agreement of both FICE and pCLE were assessed. For FICE vs. pCLE, the accuracy was 79% vs. 87%, sensitivity 94% vs. 97%, specificity 50% vs. 66%, positive predictive value 79% vs. 85%, and negative predictive value 82% vs. 92%. Interobserver agreement of FICE was fair to substantial, whereas pCLE had substantial to almost perfect agreement. Both FICE and pCLE have good operating characteristics and can facilitate the MERD diagnosis. However, among different observers, pCLE is more consistent on MERD diagnosis.

  20. Contrast-enhanced spectral mammography versus MRI: Initial results in the detection of breast cancer and assessment of tumour size

    Energy Technology Data Exchange (ETDEWEB)

    Fallenberg, E.M.; Renz, D.M. [Charite - Universitaetsmedizin Berlin, Clinic of Radiology, Berlin (Germany); Dromain, C. [Institut Gustave Roussy, Department of Radiology, Villejuif cedex (France); Diekmann, F. [St. Joseph-Stift Bremen, Department of Medical Imaging, Bremen (Germany); Engelken, F.; Krohn, M.; Singh, J.M.; Bick, U. [Charite - Universitaetsmedizin Berlin, Department of Radiology, Berlin (Germany); Ingold-Heppner, B. [Charite - Universitaetsmedizin Berlin, Institute of Pathology, Berlin (Germany); Winzer, K.J. [Charite - Universitaetsmedizin Berlin, Breast Center, Department of Gynecology, Berlin (Germany)

    2014-01-15

    To compare mammography (MG), contrast-enhanced spectral mammography (CESM), and magnetic resonance imaging (MRI) in the detection and size estimation of histologically proven breast cancers using postoperative histology as the gold standard. After ethical approval, 80 women with newly diagnosed breast cancer underwent MG, CESM, and MRI examinations. CESM was reviewed by an independent experienced radiologist, and the maximum dimension of suspicious lesions was measured. For MG and MRI, routine clinical reports of breast specialists, with judgment based on the BI-RADS lexicon, were used. Results of each imaging technique were correlated to define the index cancer. Fifty-nine cases could be compared to postoperative histology for size estimation. Breast cancer was visible in 66/80 MG, 80/80 CESM, and 77/79 MRI examinations. Average lesion largest dimension was 27.31 mm (SD 22.18) in MG, 31.62 mm (SD 24.41) in CESM, and 27.72 mm (SD 21.51) in MRI versus 32.51 mm (SD 29.03) in postoperative histology. No significant difference was found between lesion size measurement on MRI and CESM compared with histopathology. Our initial results show a better sensitivity of CESM and MRI in breast cancer detection than MG and a good correlation with postoperative histology in size assessment. (orig.)

  1. The quality of tumor size assessment by contrast-enhanced spectral mammography and the benefit of additional breast MRI.

    Science.gov (United States)

    Lobbes, Marc B I; Lalji, Ulrich C; Nelemans, Patty J; Houben, Ivo; Smidt, Marjolein L; Heuts, Esther; de Vries, Bart; Wildberger, Joachim E; Beets-Tan, Regina G

    2015-01-01

    Background - Contrast-enhanced spectral mammography (CESM) is a promising new breast imaging modality that is superior to conventional mammography for breast cancer detection. We aimed to evaluate correlation and agreement of tumor size measurements using CESM. As additional analysis, we evaluated whether measurements using an additional breast MRI exam would yield more accurate results. Methods - Between January 1(st) 2013 and April 1(st) 2014, 87 consecutive breast cancer cases that underwent CESM were collected and data on maximum tumor size measurements were gathered. In 57 cases, tumor size measurements were also available for breast MRI. Histopathological results of the surgical specimen served as gold standard in all cases. Results - The Pearson's correlation coefficients (PCC) of CESM versus histopathology and breast MRI versus histopathology were all >0.9, p1 cm between the two imaging modalities and histopathological results, we did not observe any advantage of performing an additional breast MRI after CESM in any of the cases. Conclusion - Quality of tumor size measurement using CESM is good and matches the quality of these measurement assessed by breast MRI. Additional measurements using breast MRI did not improve the quality of tumor size measurements.

  2. Contrast-enhanced spectral mammography vs. mammography and MRI - clinical performance in a multi-reader evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Fallenberg, Eva M.; Schmitzberger, Florian F.; Amer, Heba; Engelken, Florian; Bick, Ulrich; Hamm, Bernd [Charite Universitaetsmedizin Berlin, Clinic of Radiology, Campus Virchow-Klinikum, Berlin (Germany); Ingold-Heppner, Barbara [Charite - Universitaetsmedizin Berlin, Institut of Pathology, Berlin (Germany); Balleyguier, Corinne; Dromain, Clarisse [Gustave Roussy Cancer Campus, Department of Radiology, Villejuif (France); Diekmann, Felix [St. Joseph-Stift Bremen, Department of Medical Imaging, Bremen (Germany); Mann, Ritse M. [Radboud University Nijmegen Medical Centre, Department of Radiology, Nijmegen (Netherlands); Renz, Diane M. [Universitaetsklinikum Jena, Department of Radiology, Jena (Germany)

    2017-07-15

    To compare the diagnostic performance of contrast-enhanced spectral mammography (CESM) to digital mammography (MG) and magnetic resonance imaging (MRI) in a prospective two-centre, multi-reader study. One hundred seventy-eight women (mean age 53 years) with invasive breast cancer and/or DCIS were included after ethics board approval. MG, CESM and CESM + MG were evaluated by three blinded radiologists based on amended ACR BI-RADS criteria. MRI was assessed by another group of three readers. Receiver-operating characteristic (ROC) curves were compared. Size measurements for the 70 lesions detected by all readers in each modality were correlated with pathology. Reading results for 604 lesions were available (273 malignant, 4 high-risk, 327 benign). The area under the ROC curve was significantly larger for CESM alone (0.84) and CESM + MG (0.83) compared to MG (0.76) (largest advantage in dense breasts) while it was not significantly different from MRI (0.85). Pearson correlation coefficients for size comparison were 0.61 for MG, 0.69 for CESM, 0.70 for CESM + MG and 0.79 for MRI. This study showed that CESM, alone and in combination with MG, is as accurate as MRI but is superior to MG for lesion detection. Patients with dense breasts benefitted most from CESM with the smallest additional dose compared to MG. (orig.)

  3. Comparison of peripapillary choroidal thickness measurements via spectral domain optical coherence tomography with and without enhanced depth imaging.

    Science.gov (United States)

    Ayyildiz, Onder; Kucukevcilioglu, Murat; Ozge, Gokhan; Koylu, Mehmet Talay; Ozgonul, Cem; Gokce, Gokcen; Mumcuoglu, Tarkan; Durukan, Ali Hakan; Mutlu, Fatih Mehmet

    2016-05-01

    To compare peripapillary choroidal thickness (PP-CT) measurements using a spectral domain optical coherence tomography (SD-OCT) device with and without enhanced depth imaging (EDI). Sixty healthy subjects aged from 18 to 40 years were included in this study. PP-CTs were measured in the right eyes by manual segmentation via SD-OCT both with and without EDI. The intraclass correlation coefficient (ICC) for each technique and comparison of PP-CT measurements between two techniques were evaluated. The correlation between retinal nerve fiber layer (RNFL) thickness and PP-CT was also explored on images of SD-OCT without EDI. The PP-CT measurements of 55 subjects were evaluated. The ICC was 0.999 (95% CI: 0.998-1.0, p  0.05). Additionally, there was no correlation between RNFL thickness and PP-CT (r = -0.109; p = 0.335). The PP-CT measurements via SD-OCT without EDI were consistent with the measurements via SD-OCT with EDI. Ophthalmologists who do not have access to EDI technology can use images of SD-OCT without EDI to measure the peripapillary choroid for research purposes. However, thicker peripapillary choroids cannot be measured using this technique and require further modifications or newer technologies, such as SD-OCT with EDI.

  4. Contrast-enhanced spectral mammography versus MRI: Initial results in the detection of breast cancer and assessment of tumour size

    International Nuclear Information System (INIS)

    Fallenberg, E.M.; Renz, D.M.; Dromain, C.; Diekmann, F.; Engelken, F.; Krohn, M.; Singh, J.M.; Bick, U.; Ingold-Heppner, B.; Winzer, K.J.

    2014-01-01

    To compare mammography (MG), contrast-enhanced spectral mammography (CESM), and magnetic resonance imaging (MRI) in the detection and size estimation of histologically proven breast cancers using postoperative histology as the gold standard. After ethical approval, 80 women with newly diagnosed breast cancer underwent MG, CESM, and MRI examinations. CESM was reviewed by an independent experienced radiologist, and the maximum dimension of suspicious lesions was measured. For MG and MRI, routine clinical reports of breast specialists, with judgment based on the BI-RADS lexicon, were used. Results of each imaging technique were correlated to define the index cancer. Fifty-nine cases could be compared to postoperative histology for size estimation. Breast cancer was visible in 66/80 MG, 80/80 CESM, and 77/79 MRI examinations. Average lesion largest dimension was 27.31 mm (SD 22.18) in MG, 31.62 mm (SD 24.41) in CESM, and 27.72 mm (SD 21.51) in MRI versus 32.51 mm (SD 29.03) in postoperative histology. No significant difference was found between lesion size measurement on MRI and CESM compared with histopathology. Our initial results show a better sensitivity of CESM and MRI in breast cancer detection than MG and a good correlation with postoperative histology in size assessment. (orig.)

  5. Climate responses to SATIRE and SIM-based spectral solar forcing in a 3D atmosphere-ocean coupled GCM

    Directory of Open Access Journals (Sweden)

    Wen Guoyong

    2017-01-01

    Full Text Available We apply two reconstructed spectral solar forcing scenarios, one SIM (Spectral Irradiance Monitor based, the other the SATIRE (Spectral And Total Irradiance REconstruction modeled, as inputs to the GISS (Goddard Institute for Space Studies GCMAM (Global Climate Middle Atmosphere Model to examine climate responses on decadal to centennial time scales, focusing on quantifying the difference of climate response between the two solar forcing scenarios. We run the GCMAM for about 400 years with present day trace gas and aerosol for the two solar forcing inputs. We find that the SIM-based solar forcing induces much larger long-term response and 11-year variation in global averaged stratospheric temperature and column ozone. We find significant decreasing trends of planetary albedo for both forcing scenarios in the 400-year model runs. However the mechanisms for the decrease are very different. For SATIRE solar forcing, the decreasing trend of planetary albedo is associated with changes in cloud cover. For SIM-based solar forcing, without significant change in cloud cover on centennial and longer time scales, the apparent decreasing trend of planetary albedo is mainly due to out-of-phase variation in shortwave radiative forcing proxy (downwelling flux for wavelength >330 nm and total solar irradiance (TSI. From the Maunder Minimum to present, global averaged annual mean surface air temperature has a response of ~0.1 °C to SATIRE solar forcing compared to ~0.04 °C to SIM-based solar forcing. For 11-year solar cycle, the global surface air temperature response has 3-year lagged response to either forcing scenario. The global surface air 11-year temperature response to SATIRE forcing is about 0.12 °C, similar to recent multi-model estimates, and comparable to the observational-based evidence. However, the global surface air temperature response to 11-year SIM-based solar forcing is insignificant and inconsistent with observation-based evidence.

  6. Spectral response of the coral rubble, living corals, and dead corals: study case on the Spermonde Archipelago, Indonesia

    Science.gov (United States)

    Nurdin, Nurjannah; Komatsu, Teruhisa; Yamano, Hiroya; Arafat, Gulam; Rani, Chair; Akbar AS, M.

    2012-10-01

    Coral reefs play important ecological services such as providing foods, biodiversity, nutrient recycling etc. for human society. On the other hand, they are threatened by human impacts such as illegal fishing and environmental changes such as rises of sea water temperature and sea level due to global warming. Thus, it is very important to monitor dynamic spatial distributions of coral reefs and related habitats such as coral rubble, dead coral, bleached corals, seagrass, etc. Hyperspectral data, in particular, offer high potential for characterizing and mapping coral reefs because of their capability to identify individual reef components based on their detailed spectral response. We studied the optical properties by measuring in situ spectra of living corals, dead coral and coral rubble covered with algae. Study site was selected in Spermonde archipelago, South Sulawesi, Indonesia because this area is included in the highest diversity of corals in the world named as Coral Triangle, which is recognized as the global centre of marine biodiversity and a global priority for conservation. Correlation analysis and cluster analysis support that there are distinct differences in reflectance spectra among categories. Common spectral characteristic of living corals, dead corals and coral rubble covered with algae was a reflectance minimum at 674 nm. Healthy corals, dead coral covered with algae and coral rubble covered with algae showed high similarity of spectral reflectance. It is estimated that this is due to photsynthetic pigments.

  7. Development of a very fast spectral response measurement system for analysis of hydrogenated amorphous silicon solar cells and modules

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez, J.A., E-mail: jose.rodriguez@tsolar.eu [Dept. Technology, Development and Innovation, T-Solar Global S.A., Parque Tecnologico de Galicia, Avda. de Vigo 5, E-32900 San Cibrao das Vinas (Ourense) (Spain); Fortes, M. [Departamento de Electronica e Computacion, Universidade de Santiago de Compostela, 15782 Santiago de Compostela (Spain); Alberte, C.; Vetter, M.; Andreu, J. [Dept. Technology, Development and Innovation, T-Solar Global S.A., Parque Tecnologico de Galicia, Avda. de Vigo 5, E-32900 San Cibrao das Vinas (Ourense) (Spain)

    2013-01-01

    Highlights: Black-Right-Pointing-Pointer Spectral response equipment for measuring a-Si:H solar cells in a few seconds. Black-Right-Pointing-Pointer Equipment based on 16 LEDs with simultaneous illumination of the solar cell. Black-Right-Pointing-Pointer The current generated by each LED is analyzed by a Fast Fourier Transform. Black-Right-Pointing-Pointer Cheap equipment without lock-in technology for the current measurement. Black-Right-Pointing-Pointer Measurement error vs. conventional measurement less than 1% in J{sub sc}. - Abstract: An important requirement for a very fast spectral response measurement system is the simultaneous illumination of the solar cell at multiple well defined wavelengths. Nowadays this can be done by means of light emitting diodes (LEDs) available for a multitude of wavelengths. For the purpose to measure the spectral response (SR) of amorphous silicon solar cells a detailed characterization of LEDs emitting in the wavelength range from 300 nm to 800 nm was performed. In the here developed equipment the LED illumination is modulated in the frequency range from 100 Hz to 200 Hz and the current generated by each LED is analyzed by a Fast Fourier Transform (FFT) to determine the current component corresponding to each wavelength. The equipment provides a signal to noise ratio of 2-4 orders of magnitude for individual wavelengths resulting in a precise measurement of the SR over the whole wavelength range. The difference of the short circuit current determined from the SR is less than 1% in comparison to a conventional system with monochromator.

  8. Response of Spectral Reflectances and Vegetation Indices on Varying Juniper Cone Densities

    Directory of Open Access Journals (Sweden)

    Guillermo E. Ponce-Campos

    2013-10-01

    Full Text Available Juniper trees are widely distributed throughout the world and are common sources of allergies when microscopic pollen grains are transported by wind and inhaled. In this study, we investigated the spectral influences of pollen-discharging male juniper cones within a juniper canopy. This was done through a controlled outdoor experiment involving ASD FieldSpec Pro Spectroradiometer measurements over juniper canopies of varying cone densities. Broadband and narrowband spectral reflectance and vegetation index (VI patterns were evaluated as to their sensitivity and their ability to discriminate the presence of cones. The overall aim of this research was to assess remotely sensed phenological capabilities to detect pollen-bearing juniper trees for public health applications. A general decrease in reflectance values with increasing juniper cone density was found, particularly in the Green (545–565 nm and NIR (750–1,350 nm regions. In contrast, reflectances in the shortwave-infrared (SWIR, 2,000 nm to 2,350 nm region decreased from no cone presence to intermediate amounts (90 g/m2 and then increased from intermediate levels to the highest cone densities (200 g/m2. Reflectance patterns in the Red (620–700 nm were more complex due to shifting contrast patterns in absorptance between cones and juniper foliage, where juniper foliage is more absorbing than cones only within the intense narrowband region of maximum chlorophyll absorption near 680 nm. Overall, narrowband reflectances were more sensitive to cone density changes than the equivalent MODIS broadbands. In all VIs analyzed, there were significant relationships with cone density levels, particularly with the narrowband versions and the two-band vegetation index (TBVI based on Green and Red bands, a promising outcome for the use of phenocams in juniper phenology trait studies. These results indicate that spectral indices are sensitive to certain juniper phenologic traits that can potentially be

  9. Standard Test Methods for Measurement of Electrical Performance and Spectral Response of Nonconcentrator Multijunction Photovoltaic Cells and Modules

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2010-01-01

    1.1 These test methods provide special techniques needed to determine the electrical performance and spectral response of two-terminal, multijunction photovoltaic (PV) devices, both cell and modules. 1.2 These test methods are modifications and extensions of the procedures for single-junction devices defined by Test Methods E948, E1021, and E1036. 1.3 These test methods do not include temperature and irradiance corrections for spectral response and current-voltage (I-V) measurements. Procedures for such corrections are available in Test Methods E948, E1021, and E1036. 1.4 These test methods may be applied to cells and modules intended for concentrator applications. 1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and ...

  10. Immunoadjuvants enhance the febrile responses of rats to endogenous pyrogen.

    Science.gov (United States)

    Stitt, J T; Shimada, S G

    1989-11-01

    The febrile responses of male Sprague-Dawley rats to a semipurified endogenous pyrogen produced from human monocytes were characterized by establishing fever dose-response curves. The animals were then injected intravenously with a number of substances that possessed the common properties of stimulating the phagocytic activity of the cells of the reticuloendothelial system and of acting as immunoadjuvants. The substances used were zymosan, lipopolysaccharide endotoxin, and muramyl dipeptide. Three days after any of these immunoadjuvants were injected, the fever sensitivity of the rats was remeasured. In each case, the slope of the fever dose-response curve tripled, and in some instances the response threshold for fever response was reduced by factors of three to eight. Furthermore, the maximum increase in body temperature produced by the endogenous pyrogen was more than doubled after immunoadjuvant treatment. By contrast latex beads, which are also phagocytized by the cells of the reticuloendothelial system but do not subsequently increase their phagocytic index nor do they enhance immune responses, had no effect on the fever sensitivity of rats in response to endogenous pyrogen. In the light of these findings, it is suggested that the febrile responses of rats to endogenous pyrogen are mediated in some manner by cells that possess some of the properties of reticuloendothelial cells. The location of these putative cells must be close to the circulation, because the immunoadjuvants used in this study were, for the most part, large molecular weight molecules that could not cross the blood-brain barrier easily.

  11. Enhancement of Immune Memory Responses to Respiratory Infection

    Science.gov (United States)

    2017-08-01

    Unlimited Distribution 13. SUPPLEMENTARY NOTES 14. ABSTRACT Maintenance of long - term immunological memory against pathogens is crucial for the rapid...highly expressed in memory B cells in mice, and Atg7 is required for maintenance of long - term memory B cells needed to protect against influenza...AWARD NUMBER: W81XWH-16-1-0361 TITLE: Enhancement of Immune Memory Responses to Respiratory Infection PRINCIPAL INVESTIGATORs: Dr Farrah

  12. Spectral Induced Polarization Response of Biofilm Formation in Hanford Vadose Zone Sediment

    Science.gov (United States)

    Garcia, A.; Katsenovich, Y.; Lee, B.; Whitman, D.

    2017-12-01

    As a result of the U.S. Nuclear weapons program during the second world war and the cold war, there now exists a significant amount of uranium contamination at the U.S. Department of Energy Hanford site located in Washington state. In-situ immobilization of mobile uranium via injections of a soluble sodium tripolyphosphate amendment may prove effective in the formation of insoluble uranyl phosphate mineral, autunite. However, the injected polyphosphate undergoes hydrolysis in aqueous solutions to form orthophosphate, which serves as a readily available nutrient for the various microorganisms in the sediment. Sediment-filled column experiments conducted under saturated oxygen restricted conditions using geophysical Spectral Induced Polarization technique have shown the impact of microbes on the dissolution of autunite, a calcium uranyl phosphate mineral. Spectral Induced Polarization may be an effective way to track changes indicative of bacterial activities on the surrounding environment. This method can be a cost-effective alternative to the drilling of boreholes at a field scale.

  13. Intraspecific responses of 188 rice cultivars to enhanced UVB radiation

    International Nuclear Information System (INIS)

    Dai, Q.; Peng, A.; Chavez, A.Q.; Vergara, B.S.

    1994-01-01

    Phytotron studies were conducted to determine the intraspecific variation in sensitivity of rice (Oryza sativa L.) to enhanced UVB and to test the hypothesis that rice cultivars originating from regions with higher ambient UVB radiation are more tolerant to enhanced UVB. Out of the 188 rice cultivars (from various rice growing regions and ecosystems) tested, 143 had significantly reduced plant height, 52 had smaller leaf area, 61 had lower plant dry weight and 41 had less tiller number under elevated UVB radiation (13.0 kJ m −2 day −1 ) for 3 weeks. Six cultivars showed significant positive growth response to enhanced UVB radiation, although the mechanism is not clear at present. These six cultivars were from the summer rice crop of Bangladesh and from high elevation rice areas where prevailing UVB radiation is most likely to be greater. However, there was no correlation between the dry matter changes under enhanced UVB and the ambient UVB level at the origin of the cultivar across the 188 cultivars tested. Therefore, cultivars originating from regions with higher ambient UVB are not necessarily more tolerant to enhanced UVB radiation. (author)

  14. Enhanced terahertz magnetic dipole response by subwavelength fiber

    Directory of Open Access Journals (Sweden)

    Shaghik Atakaramians

    2018-05-01

    Full Text Available Dielectric sub-wavelength particles have opened up a new platform for realization of magnetic light. Recently, we have demonstrated that a dipole emitter by a sub-wavelength fiber leads to an enhanced magnetic response. Here, we experimentally demonstrate an enhanced magnetic dipole source in the terahertz frequency range. By placing the fiber next to the hole in a metal screen, we find that the radiation power can be enhanced more than one order of magnitude. The enhancement is due to the excitation of the Mie-type resonances in the fiber. We demonstrate that such a system is equivalent to a double-fiber system excited by a magnetic source. This coupled magnetic dipole and optical fiber system can be considered a unit cell of metasurfaces for manipulation of terahertz radiation and is a proof-of-concept of a possibility to achieve enhanced radiation of a dipole source in proximity of a sub-wavelength fiber. It can also be scaled down to optical frequencies opening up promising avenues for developing integrated nanophotonic devices such as nanoantennas or lasers on fibers.

  15. Immunomodulator-based enhancement of anti smallpox immune responses.

    Directory of Open Access Journals (Sweden)

    Osmarie Martínez

    Full Text Available The current live vaccinia virus vaccine used in the prevention of smallpox is contraindicated for millions of immune-compromised individuals. Although vaccination with the current smallpox vaccine produces protective immunity, it might result in mild to serious health complications for some vaccinees. Thus, there is a critical need for the production of a safe virus-free vaccine against smallpox that is available to everyone. For that reason, we investigated the impact of imiquimod and resiquimod (Toll-like receptors agonists, and the codon-usage optimization of the vaccinia virus A27L gene in the enhancement of the immune response, with intent of producing a safe, virus-free DNA vaccine coding for the A27 vaccinia virus protein.We analyzed the cellular-immune response by measuring the IFN-γ production of splenocytes by ELISPOT, the humoral-immune responses measuring total IgG and IgG2a/IgG1 ratios by ELISA, and the TH1 and TH2 cytokine profiles by ELISA, in mice immunized with our vaccine formulation.The proposed vaccine formulation enhanced the A27L vaccine-mediated production of IFN-γ on mouse spleens, and increased the humoral immunity with a TH1-biased response. Also, our vaccine induced a TH1 cytokine milieu, which is important against viral infections.These results support the efforts to find a new mechanism to enhance an immune response against smallpox, through the implementation of a safe, virus-free DNA vaccination platform.

  16. Immunomodulator-Based Enhancement of Anti Smallpox Immune Responses

    Science.gov (United States)

    Martínez, Osmarie; Miranda, Eric; Ramírez, Maite; Santos, Saritza; Rivera, Carlos; Vázquez, Luis; Sánchez, Tomás; Tremblay, Raymond L.; Ríos-Olivares, Eddy; Otero, Miguel

    2015-01-01

    Background The current live vaccinia virus vaccine used in the prevention of smallpox is contraindicated for millions of immune-compromised individuals. Although vaccination with the current smallpox vaccine produces protective immunity, it might result in mild to serious health complications for some vaccinees. Thus, there is a critical need for the production of a safe virus-free vaccine against smallpox that is available to everyone. For that reason, we investigated the impact of imiquimod and resiquimod (Toll-like receptors agonists), and the codon-usage optimization of the vaccinia virus A27L gene in the enhancement of the immune response, with intent of producing a safe, virus-free DNA vaccine coding for the A27 vaccinia virus protein. Methods We analyzed the cellular-immune response by measuring the IFN-γ production of splenocytes by ELISPOT, the humoral-immune responses measuring total IgG and IgG2a/IgG1 ratios by ELISA, and the TH1 and TH2 cytokine profiles by ELISA, in mice immunized with our vaccine formulation. Results The proposed vaccine formulation enhanced the A27L vaccine-mediated production of IFN-γ on mouse spleens, and increased the humoral immunity with a TH1-biased response. Also, our vaccine induced a TH1 cytokine milieu, which is important against viral infections. Conclusion These results support the efforts to find a new mechanism to enhance an immune response against smallpox, through the implementation of a safe, virus-free DNA vaccination platform. PMID:25875833

  17. Enhancing the benefits of written emotional disclosure through response training.

    Science.gov (United States)

    Konig, Andrea; Eonta, Alison; Dyal, Stephanie R; Vrana, Scott R

    2014-05-01

    Writing about a personal stressful event has been found to have psychological and physical health benefits, especially when physiological response increases during writing. Response training was developed to amplify appropriate physiological reactivity in imagery exposure. The present study examined whether response training enhances the benefits of written emotional disclosure. Participants were assigned to either a written emotional disclosure condition (n=113) or a neutral writing condition (n=133). Participants in each condition wrote for 20 minutes on 3 occasions and received response training (n=79), stimulus training (n=84) or no training (n=83). Heart rate and skin conductance were recorded throughout a 10-minute baseline, 20-minute writing, and a 10-minute recovery period. Self-reported emotion was assessed in each session. One month after completing the sessions, participants completed follow-up assessments of psychological and physical health outcomes. Emotional disclosure elicited greater physiological reactivity and self-reported emotion than neutral writing. Response training amplified physiological reactivity to emotional disclosure. Greater heart rate during emotional disclosure was associated with the greatest reductions in event-related distress, depression, and physical illness symptoms at follow-up, especially among response trained participants. Results support an exposure explanation of emotional disclosure effects and are the first to demonstrate that response training facilitates emotional processing and may be a beneficial adjunct to written emotional disclosure. Copyright © 2014. Published by Elsevier Ltd.

  18. Enhancing the Benefits of Written Emotional Disclosure through Response Training

    Science.gov (United States)

    Konig, Andrea; Eonta, Alison; Dyal, Stephanie R.; Vrana, Scott R.

    2014-01-01

    Writing about a personal stressful event has been found to have psychological and physical health benefits, especially when physiological response increases during writing. Response training was developed to amplify appropriate physiological reactivity in imagery exposure. The present study examined whether response training enhances the benefits of written emotional disclosure. Participants were assigned to either a written emotional disclosure condition (n = 113) or a neutral writing condition (n = 133). Participants in each condition wrote for 20 minutes on three occasions and received response training (n = 79), stimulus training (n = 84) or no training (n = 83). Heart rate and skin conductance were recorded throughout a 10-minute baseline, 20-minute writing, and a 10-minute recovery period. Self-reported emotion was assessed in each session. One month after completing the sessions, participants completed follow-up assessments of psychological and physical health outcomes. Emotional disclosure elicited greater physiological reactivity and self-reported emotion than neutral writing. Response training amplified physiological reactivity to emotional disclosure. Greater heart rate during emotional disclosure was associated with the greatest reductions in event-related distress, depression, and physical illness symptoms at follow-up, especially among response trained participants. Results support an exposure explanation of emotional disclosure effects and are the first to demonstrate that response training facilitates emotional processing and may be a beneficial adjunct to written emotional disclosure. PMID:24680230

  19. Assessing tumor extent on contrast-enhanced spectral mammography versus full-field digital mammography and ultrasound.

    Science.gov (United States)

    Patel, Bhavika K; Garza, Sandra Alheli; Eversman, Sarah; Lopez-Alvarez, Yania; Kosiorek, Heidi; Pockaj, Barbara A

    To compare breast cancer size measurements on full-field digital mammography (FFDM), contrast-enhanced spectral mammography (CEDM), and ultrasound (US), with histologic tumor size used as the reference standard. Material and methods The HIPAA complaint, IRB approved study comprised 88 women with newly diagnosed breast cancer who underwent FFDM and CEDM;74 also had US. Breast density, histologic subtype, and maximum tumor measurements were recorded. Pearson correlation coefficients for FFDM, US, and CEDM vs histopathology were 0.598, 0.639, and 0.859, respectively (P<0.001). The following correlation coefficients were calculated for dense breasts (n=48): histopathology vs FFDM (0.555), US (0.633), and CEDM (0.843) (P<0.001); for nondense breasts (n=40), they were FFDM (0.618), US (0.512), and CEDM (0.885) (P<0.001). For size difference, the mean (SD) for histopathology vs FFDM, US, and CEDM was -1.3 (11.9) mm, -2.8 (11.1) mm, and 2.9 (9.5) mm, respectively. Limits of agreement were -24.8 to 22.0mm, -24.5 to 18.8mm, and -15.6 to 21.4mm, respectively. In patients with biopsy-proven malignancy, size measurements correlated well with histopathologic size, and were higher on CEDM than those for FFDM and US in patients with dense or nondense breasts. The added value of CEDM as a supplement to FFDM in determining tumor size, however, was greater in patients with dense breasts. CEDM may be a promising alternative preoperative measurement tool for breast cancer patients with dense breasts and/or limited access or contraindications to MRI. Copyright © 2017 Elsevier Inc. All rights reserved.

  20. Contrast-enhanced spectral mammography: Does mammography provide additional clinical benefits or can some radiation exposure be avoided?

    Science.gov (United States)

    Fallenberg, Eva Maria; Dromain, Clarisse; Diekmann, Felix; Renz, Diane M; Amer, Heba; Ingold-Heppner, Barbara; Neumann, Avidan U; Winzer, Klaus J; Bick, Ulrich; Hamm, Bernd; Engelken, Florian

    2014-07-01

    The purpose of this study was to compare contrast-enhanced spectral mammography (CESM) with mammography (MG) and combined CESM + MG in terms of detection and size estimation of histologically proven breast cancers in order to assess the potential to reduce radiation exposure. A total of 118 patients underwent MG and CESM and had final histological results. CESM was performed as a bilateral examination starting 2 min after injection of iodinated contrast medium. Three independent blinded radiologists read the CESM, MG, and CESM + MG images with an interval of at least 4 weeks to avoid case memorization. Sensitivity and size measurement correlation and differences were calculated, average glandular dose (AGD) levels were compared, and breast densities were reported. Fisher's exact and Wilcoxon tests were performed. A total of 107 imaging pairs were available for analysis. Densities were ACR1: 2, ACR2: 45, ACR3: 42, and ACR4: 18. Mean AGD was 1.89 mGy for CESM alone, 1.78 mGy for MG, and 3.67 mGy for the combination. In very dense breasts, AGD of CESM was significantly lower than MG. Sensitivity across readers was 77.9 % for MG alone, 94.7 % for CESM, and 95 % for CESM + MG. Average tumor size measurement error compared to postsurgical pathology was -0.6 mm for MG, +0.6 mm for CESM, and +4.5 mm for CESM + MG (p < 0.001 for CESM + MG vs. both modalities). CESM alone has the same sensitivity and better size assessment as CESM + MG and was significantly better than MG with only 6.2 % increase in AGD. The combination of CESM + MG led to systematic size overestimation. When a CESM examination is planned, additional MG can be avoided, with the possibility of saving up to 61 % of radiation dose, especially in patients with dense breasts.

  1. Contrast-enhanced spectral mammography vs. mammography and MRI - clinical performance in a multi-reader evaluation.

    Science.gov (United States)

    Fallenberg, Eva M; Schmitzberger, Florian F; Amer, Heba; Ingold-Heppner, Barbara; Balleyguier, Corinne; Diekmann, Felix; Engelken, Florian; Mann, Ritse M; Renz, Diane M; Bick, Ulrich; Hamm, Bernd; Dromain, Clarisse

    2017-07-01

    To compare the diagnostic performance of contrast-enhanced spectral mammography (CESM) to digital mammography (MG) and magnetic resonance imaging (MRI) in a prospective two-centre, multi-reader study. One hundred seventy-eight women (mean age 53 years) with invasive breast cancer and/or DCIS were included after ethics board approval. MG, CESM and CESM + MG were evaluated by three blinded radiologists based on amended ACR BI-RADS criteria. MRI was assessed by another group of three readers. Receiver-operating characteristic (ROC) curves were compared. Size measurements for the 70 lesions detected by all readers in each modality were correlated with pathology. Reading results for 604 lesions were available (273 malignant, 4 high-risk, 327 benign). The area under the ROC curve was significantly larger for CESM alone (0.84) and CESM + MG (0.83) compared to MG (0.76) (largest advantage in dense breasts) while it was not significantly different from MRI (0.85). Pearson correlation coefficients for size comparison were 0.61 for MG, 0.69 for CESM, 0.70 for CESM + MG and 0.79 for MRI. This study showed that CESM, alone and in combination with MG, is as accurate as MRI but is superior to MG for lesion detection. Patients with dense breasts benefitted most from CESM with the smallest additional dose compared to MG. • CESM has comparable diagnostic performance (ROC-AUC) to MRI for breast cancer diagnostics. • CESM in combination with MG does not improve diagnostic performance. • CESM has lower sensitivity but higher specificity than MRI. • Sensitivity differences are more pronounced in dense and not significant in non-dense breasts. • CESM and MRI are significantly superior to MG, particularly in dense breasts.

  2. Spectrally-resolved response properties of the three most advanced FRET based fluorescent protein voltage probes.

    Directory of Open Access Journals (Sweden)

    Hiroki Mutoh

    Full Text Available Genetically-encoded optical probes for membrane potential hold the promise of monitoring electrical signaling of electrically active cells such as specific neuronal populations in intact brain tissue. The most advanced class of these probes was generated by molecular fusion of the voltage sensing domain (VSD of Ci-VSP with a fluorescent protein (FP pair. We quantitatively compared the three most advanced versions of these probes (two previously reported and one new variant, each involving a spectrally distinct tandem of FPs. Despite these different FP tandems and dissimilarities within the amino acid sequence linking the VSD to the FPs, the amplitude and kinetics of voltage dependent fluorescence changes were surprisingly similar. However, each of these fluorescent probes has specific merits when considering different potential applications.

  3. Responsivity Enhanced NMOSFET Photodetector Fabricated by Standard CMOS Technology

    Directory of Open Access Journals (Sweden)

    Fuwei Wu

    2015-01-01

    Full Text Available Increasing the responsivity is one of the important issues for a photodetector. In this paper, we demonstrate an improved NMOSFET photodetector by using deep-n-well (DNW structure which can improve the responsivity of the photodetector significantly. The experimental results show that the responsivity can be enhanced greatly by the DNW structure and is much larger than the previous work when DNW is biased with 0.5 V, while the dark current exhibits almost no increase. Further characterization indicates that the diode formed by the bulk and DNW can efficiently absorb photons and has a large gain factor of the photocurrent especially under low light condition, which gives a more promising application for the detector to detect the weak light.

  4. Enhancing the electrochemical response of myoglobin with carbon nanotube electrodes.

    Science.gov (United States)

    Esplandiu, M J; Pacios, M; Cyganek, L; Bartroli, J; del Valle, M

    2009-09-02

    In this paper, the electrochemical behavior of different myoglobin-modified carbon electrodes is evaluated. In particular, the performance of voltammetric biosensors made of forest-like carbon nanotubes, carbon nanotube composites and graphite composites is compared by monitoring mainly the electrocatalytic reduction of H(2)O(2) by myoglobin and their corresponding electroanalytical characteristics. Graphite composites showed the worst electroanalytical performance, exhibiting a small linear range, a limit of detection (LOD) of 9 x 10(-5) M and low sensitivity. However, it was found that the electrochemical response was enhanced with the use of carbon nanotube-based electrodes with LOD up to 5 x 10(-8) M, higher sensitivities and wider linear range response. On the one hand, in the case of the CNT epoxy composite, the improvement in the response can be mainly attributed to its more porous surface which allows the immobilization of higher amounts of the electroactive protein. On the other hand, in the case of the forest-like CNT electrodes, the enhancement is due to an increase in the electron transfer kinetics. These findings encourage the use of myoglobin-modified carbon nanotube electrodes as potential (bio)sensors of H(2)O(2) or O(2) in biology, microbiology and environmental fields.

  5. HDR Image Quality Enhancement Based on Spatially Variant Retinal Response

    Directory of Open Access Journals (Sweden)

    Horiuchi Takahiko

    2010-01-01

    Full Text Available There is a growing demand for being able to display high dynamic range (HDR images on low dynamic range (LDR devices. Tone mapping is a process for enhancing HDR image quality on an LDR device by converting the tonal values of the original image from HDR to LDR. This paper proposes a new tone mapping algorithm for enhancing image quality by deriving a spatially-variant operator for imitating S-potential response in human retina, which efficiently improves local contrasts while conserving good global appearance. The proposed tone mapping operator is studied from a system construction point of view. It is found that the operator is regarded as a natural extension of the Retinex algorithm by adding a global adaptation process to the local adaptation. The feasibility of the proposed algorithm is examined in detail on experiments using standard HDR images and real HDR scene images, comparing with conventional tone mapping algorithms.

  6. Contrast-enhanced spectral mammography in recalls from the Dutch breast cancer screening program : validation of results in a large multireader, multicase study

    OpenAIRE

    Lalji, U C; Houben, I P L; Prevos, R; Gommers, S; van Goethem, M; Vanwetswinkel, S; Pijnappel, R; Steeman, R; Frotscher, C; Mok, W; Nelemans, P; Smidt, M L; Beets-Tan, R G; Wildberger, J E; Lobbes, M B I

    2016-01-01

    OBJECTIVES: Contrast-enhanced spectral mammography (CESM) is a promising problem-solving tool in women referred from a breast cancer screening program. We aimed to study the validity of preliminary results of CESM using a larger panel of radiologists with different levels of CESM experience. METHODS: All women referred from the Dutch breast cancer screening program were eligible for CESM. 199 consecutive cases were viewed by ten radiologists. Four had extensive CESM experience, three had no C...

  7. Could parenchymal enhancement on contrast-enhanced spectral mammography (CESM) represent a new breast cancer risk factor? Correlation with known radiology risk factors.

    Science.gov (United States)

    Savaridas, S L; Taylor, D B; Gunawardana, D; Phillips, M

    2017-12-01

    To compare background parenchymal enhancement (BPE) on contrast-enhanced (CE) spectral mammography (CESM) with CE magnetic resonance imaging (MRI), and evaluate how these relate to hormonal status, mammographic breast density (MBD) and MRI fibroglandular tissue volume (FGTV). Between June 2012 to October 2015, participants in a cancer staging study underwent full-field digital mammography (FFDM), CEMRI, and CESM. Two readers independently rated FGTV, MBD, and BPE using the Breast Imaging-Reporting and Data System (BI-RADS) criteria. Inter-reader reliability was estimated using weighted kappa (k) and correlations between BPE, MBD, and FGTV calculated using Spearman's correlation coefficient. Associations with hormonal status were evaluated using multilevel ordinal regression analysis. Of the 96 eligible participants, 66 women (35-77 years) underwent CESM and CEMRI. Reasons for exclusion were declined or withdrawn consent (n=18), inadequate renal function (n=2), claustrophobia (n=2), previous reaction to contrast medium (n=2), mild reaction to contrast medium following CESM (n=2), lack of vascular access (n=1), neoadjuvant chemotherapy (n=1), CESM equipment failure (n=1), and unclear in one case. Inter-reader agreement was substantial (k=0.67) for CESM BPE, slight (k=0.19) for CEMRI BPE, moderate (k=0.57) for MRI FGTV and fair (k=0.35) for MBD. CESM BPE showed significant correlation with MBD (rho=0.36, p<0.0001), FGTV (rho=0.52, p<0.0001), and MRI BPE (rho=0.49, p<0.0001). BPE was significantly reduced in the post-menopausal group for CEMRI and CESM (p<0.05). CESM BPE did not significantly fluctuate during the menstrual cycle. CESM BPE is correlated with MBD, FGTV, and CEMRI BPE, has better inter-reader reliability than CEMRI, and is not influenced by the menstrual cycle. Grading the degree of BPE on CESM could be a useful addition to breast cancer risk assessment tools. Copyright © 2017 The Royal College of Radiologists. Published by Elsevier Ltd. All rights

  8. Biotin deficiency enhances the inflammatory response of human dendritic cells.

    Science.gov (United States)

    Agrawal, Sudhanshu; Agrawal, Anshu; Said, Hamid M

    2016-09-01

    The water-soluble biotin (vitamin B7) is indispensable for normal human health. The vitamin acts as a cofactor for five carboxylases that are critical for fatty acid, glucose, and amino acid metabolism. Biotin deficiency is associated with various diseases, and mice deficient in this vitamin display enhanced inflammation. Previous studies have shown that biotin affects the functions of adaptive immune T and NK cells, but its effect(s) on innate immune cells is not known. Because of that and because vitamins such as vitamins A and D have a profound effect on dendritic cell (DC) function, we investigated the effect of biotin levels on the functions of human monocyte-derived DCs. Culture of DCs in a biotin-deficient medium (BDM) and subsequent activation with LPS resulted in enhanced secretion of the proinflammatory cytokines TNF-α, IL-12p40, IL-23, and IL-1β compared with LPS-activated DCs cultured in biotin-sufficient (control) and biotin-oversupplemented media. Furthermore, LPS-activated DCs cultured in BDM displayed a significantly higher induction of IFN-γ and IL-17 indicating Th1/Th17 bias in T cells compared with cells maintained in biotin control or biotin-oversupplemented media. Investigations into the mechanisms suggested that impaired activation of AMP kinase in DCs cultured in BDM may be responsible for the observed increase in inflammatory responses. In summary, these results demonstrate for the first time that biotin deficiency enhances the inflammatory responses of DCs. This may therefore be one of the mechanism(s) that mediates the observed inflammation that occurs in biotin deficiency.

  9. Measurements of spectral responses for developing fiber-optic pH sensor

    Science.gov (United States)

    Yoo, Wook Jae; Heo, Ji Yeon; Jang, Kyoung Won; Seo, Jeong Ki; Moon, Jin Soo; Park, Jang-Yeon; Park, Byung Gi; Cho, Seunghyun; Lee, Bongsoo

    2011-01-01

    In this study, we have fabricated a fiber-optic pH sensor, which is composed of a light source, a pH-sensing probe, plastic optical fibers and a spectrometer, for determining the degree of infection by Helicobacter pylori in the stomach. As pH indicators, phenol red and m-cresol purple are used, and pH liquid solutions are prepared by mixing phenol red or m-cresol purple solutions and various kinds of pH buffer solutions. The light emitted by a light source is guided by plastic optical fibers to the pH liquid solution, and the optical characteristic of a reflected light is changed according to the color variations of the pH indicator in the pH-sensing probe. Therefore, we have measured the intensities and wavelength shifts of the reflected lights, which change according to the color variations of indicators at different pH values, by using a spectrometer for spectral analysis. Also, the relationships between the pH values of liquid solutions and the optical properties of the modulated lights are obtained on the basis of the changes of the colors of indicators.

  10. Spectral analysis of white ash response to emerald ash borer infestations

    Science.gov (United States)

    Calandra, Laura

    The emerald ash borer (EAB) (Agrilus planipennis Fairmaire) is an invasive insect that has killed over 50 million ash trees in the US. The goal of this research was to establish a method to identify ash trees infested with EAB using remote sensing techniques at the leaf-level and tree crown level. First, a field-based study at the leaf-level used the range of spectral bands from the WorldView-2 sensor to determine if there was a significant difference between EAB-infested white ash (Fraxinus americana) and healthy leaves. Binary logistic regression models were developed using individual and combinations of wavelengths; the most successful model included 545 and 950 nm bands. The second half of this research employed imagery to identify healthy and EAB-infested trees, comparing pixel- and object-based methods by applying an unsupervised classification approach and a tree crown delineation algorithm, respectively. The pixel-based models attained the highest overall accuracies.

  11. UTILIZATION OF FUNDUS AUTOFLUORESCENCE, SPECTRAL DOMAIN OPTICAL COHERENCE TOMOGRAPHY, AND ENHANCED DEPTH IMAGING IN THE CHARACTERIZATION OF BIETTI CRYSTALLINE DYSTROPHY IN DIFFERENT STAGES.

    Science.gov (United States)

    Li, Qian; Li, Yang; Zhang, Xiaohui; Xu, Zhangxing; Zhu, Xiaoqing; Ma, Kai; She, Haicheng; Peng, Xiaoyan

    2015-10-01

    To characterize Bietti crystalline dystrophy (BCD) in different stages using multiple imaging modalities. Sixteen participants clinically diagnosed as BCD were included in the retrospective study and were categorized into 3 stages according to fundus photography. Eleven patients were genetically confirmed. Fundus autofluorescence, spectral domain optical coherence tomography, and enhanced depth imaging features of BCD were analyzed. On fundus autofluorescence, the abnormal autofluorescence was shown to enlarge in area and decrease in intensity with stages. Using spectral domain optical coherence tomography, the abnormalities in Stage 1 were observed to localize in outer retinal layers, whereas in Stage 2 and Stage 3, more extensive retinal atrophy was seen. In enhanced depth imaging, the subfoveal choroidal layers were delineated clearly in Stage 1; in Stage 2, destructions were primarily found in the choriocapillaris with associated alterations in the outer vessels; Stage 3 BCD displayed severe choroidal thinning. Choroidal neovascularization and macular edema were exhibited with high incidence. IVS6-8del17bp/inGC of the CYP4V2 gene was the most common mutant allele. Noninvasive fundus autofluorescence, spectral domain optical coherence tomography, and enhanced depth imaging may help to characterize the chorioretinal pathology of BCD at different degrees, and therefore, we propose staging of BCD depending on those methods. Physicians should be cautious of the vision-threatening complications of the disease.

  12. Efficient 3D frequency response modeling with spectral accuracy by the rapid expansion method

    KAUST Repository

    Chu, Chunlei; Stoffa, Paul L.

    2012-01-01

    Frequency responses of seismic wave propagation can be obtained either by directly solving the frequency domain wave equations or by transforming the time domain wavefields using the Fourier transform. The former approach requires solving systems

  13. Spectral response of crystalline acetanilide and N -methylacetamide: Vibrational self-trapping in hydrogen-bonded crystals

    Science.gov (United States)

    Edler, Julian; Hamm, Peter

    2004-06-01

    Femtosecond pump-probe and Fourier transform infrared spectroscopy is applied to compare the spectral response of the amide I band and the NH-stretching band of acetanilide (ACN) and N -methylacetamide (NMA), as well as their deuterated derivatives. Both molecules form hydrogen-bonded molecular crystals that are regarded to be model systems for polypeptides and proteins. The amide I bands of both ACN and NMA show a temperature-dependent sideband, while the NH bands are accompanied by a sequence of equidistantly spaced satellite peaks. These spectral anomalies are interpreted as a signature of vibrational self-trapping. Two different types of states can be identified in both crystals in the pump-probe signal: a delocalized free-exciton state and a set of localized self-trapped states. The phonons that mediate self-trapping in ACN and deuterated ACN are identified by their temperature dependence, confirming our previous results. The study shows that the substructure of the NH band in NMA (amide A and amide B bands) originates, at least partly, from vibrational self-trapping and not, as often assumed, from a Fermi resonance.

  14. Vigabatrin can enhance electroretinographic responses in pigmented and albino rats.

    Science.gov (United States)

    Akula, James D; Noonan, Emily R; Di Nardo, Alessia; Favazza, Tara L; Zhang, Nan; Sahin, Mustafa; Hansen, Ronald M; Fulton, Anne B

    2015-08-01

    To evaluate the effects of the antiepileptic medication vigabatrin (VGB) on the retina of pigmented rats. Scotopic and photopic electroretinograms were recorded from dark- and light-adapted Long-Evans (pigmented) and Sprague Dawley (albino) rats administered, daily, 52-55 injections of 250 mg·kg(-1)·day(-1) VGB or 25-26 injections of 500 mg·kg(-1)·day(-1) VGB, or a corresponding number of sham injections. Sensitivity and saturated amplitude of the rod photoresponse (S, Rm(P3)) and postreceptor response (1/σ, Vm) were derived, as were sensitivity and amplitude of the cone-mediated postreceptor response (1/σ(cone), Vm(cone)). The oscillatory potentials and responses to a series of flickering lights (6.25, 12.5, 25 and 50 Hz) were studied in the time and frequency domains. A subset of rats' eyes was harvested for Western blotting or histology. Of the parameters derived from dark-adapted ERG responses, in both pigmented and albino rats, VGB repeatedly and reliably enhanced electroretinographic parameters; no significant ERG deficits were noted. No significant alterations were observed in ER/oxidative stress or in the Akt cell death/survival pathway. There were migrations of photoreceptor nuclei toward the RPE and outgrowths of bipolar cell dendrites into the outer nuclear layer in VGB-treated rats; these were never observed in sham-treated animals. Although VGB is associated with retinal dysfunction in patients and VGB toxicity has been demonstrated by other laboratories in the albino rat, in our pigmented and albino rats, VGB did not induce deficits in, but rather enhanced, retinal function. Nonetheless, retinal neuronal dysplasia was observed.

  15. Transgenerational effects enhance specific immune response in a wild passerine

    Directory of Open Access Journals (Sweden)

    Juli Broggi

    2016-03-01

    Full Text Available Vertebrate mothers transfer diverse compounds to developing embryos that can affect their development and final phenotype (i.e., maternal effects. However, the way such effects modulate offspring phenotype, in particular their immunity, remains unclear. To test the impact of maternal effects on offspring development, we treated wild breeding house sparrows (Passer domesticus in Sevilla, SE Spain with Newcastle disease virus (NDV vaccine. Female parents were vaccinated when caring for first broods, eliciting a specific immune response to NDV. The immune response to the same vaccine, and to the PHA inflammatory test were measured in 11-day-old chicks from their following brood. Vaccinated chicks from vaccinated mothers developed a stronger specific response that was related to maternal NDV antibody concentration while rearing their chicks. The chicks’ carotenoid concentration and total antioxidant capacity in blood were negatively related to NDV antibody concentration, whereas no relation with PHA response was found. Specific NDV antibodies could not be detected in 11-day-old control chicks from vaccinated mothers, implying that maternally transmitted antibodies are not directly involved but may promote offspring specific immunity through a priming effect, while other immunity components remain unaffected. Maternally transmitted antibodies in the house sparrow are short-lived, depend on maternal circulation levels and enhance pre-fledging chick specific immunity when exposed to the same pathogens as the mothers.

  16. Response variability to glucose facilitation of cognitive enhancement.

    Science.gov (United States)

    Owen, Lauren; Scholey, Andrew; Finnegan, Yvonne; Sünram-Lea, Sandra I

    2013-11-01

    Glucose facilitation of cognitive function has been widely reported in previous studies (including our own). However, several studies have also failed to detect glucose facilitation. There is sparsity of research examining the factors that modify the effect of glucose on cognition. The aims of the present study were to (1) demonstrate the previously observed enhancement of cognition through glucose administration and (2) investigate some of the factors that may exert moderating roles on the behavioural response to glucose, including glucose regulation, body composition (BC) and hypothalamic–pituitary–adrenal axis response. A total of twenty-four participants took part in a double-blind, placebo-controlled, randomised, repeated-measures study, which examined the effect of 25 and 60 g glucose compared with placebo on cognitive function. At 1 week before the study commencement, all participants underwent an oral glucose tolerance test. Glucose facilitated performance on tasks of numeric and spatial working memory, verbal declarative memory and speed of recognition. Moderating variables were examined using several indices of glucoregulation and BC. Poorer glucoregulation predicted improved immediate word recall accuracy following the administration of 25 g glucose compared with placebo. Those with better glucoregulation showed performance decrements on word recall accuracy following the administration of 25 g glucose compared with placebo. These findings are in line with accumulating evidence that glucose load may preferentially enhance cognition in those with poorer glucoregulation. Furthermore, the finding that individuals with better glucoregulation may suffer impaired performance following a glucose load is novel and requires further substantiation.

  17. Eliminating the non-Gaussian spectral response of X-ray absorbers for transition-edge sensors

    Science.gov (United States)

    Yan, Daikang; Divan, Ralu; Gades, Lisa M.; Kenesei, Peter; Madden, Timothy J.; Miceli, Antonino; Park, Jun-Sang; Patel, Umeshkumar M.; Quaranta, Orlando; Sharma, Hemant; Bennett, Douglas A.; Doriese, William B.; Fowler, Joseph W.; Gard, Johnathon D.; Hays-Wehle, James P.; Morgan, Kelsey M.; Schmidt, Daniel R.; Swetz, Daniel S.; Ullom, Joel N.

    2017-11-01

    Transition-edge sensors (TESs) as microcalorimeters for high-energy-resolution X-ray spectroscopy are often fabricated with an absorber made of materials with high Z (for X-ray stopping power) and low heat capacity (for high resolving power). Bismuth represents one of the most compelling options. TESs with evaporated bismuth absorbers have shown spectra with undesirable and unexplained low-energy tails. We have developed TESs with electroplated bismuth absorbers over a gold layer that are not afflicted by this problem and that retain the other positive aspects of this material. To better understand these phenomena, we have studied a series of TESs with gold, gold/evaporated bismuth, and gold/electroplated bismuth absorbers, fabricated on the same die with identical thermal coupling. We show that the bismuth morphology is linked to the spectral response of X-ray TES microcalorimeters.

  18. Enhancing optical response of graphene through stochastic resonance

    Science.gov (United States)

    Ying, Lei; Huang, Liang; Lai, Ying-Cheng

    2018-04-01

    Enhancing the optical response of graphene is a topic of interest with applications in optoelectronics. Subject to light irradiation, graphene can exhibit nontrivial topologically insulating states, effectively turning itself into a Floquet topological insulator due to the time periodicity of the external driving. We find that, when random disorder is present, its interplay with the topologically insulating states can have a dramatic effect on electronic transport through graphene. In particular, we consider the prototypical setting where a graphene nanoribbon is irradiated by circularly polarized light, where the length of the nanoribbon is sufficiently long so that evanescent states have little effect on transport. We uncover a resonance phenomenon in which the conductance is enhanced as the disorder strength is increased from zero, reaches a maximum value for an optimal level of disorder, and decreases as the disorder is strengthened further. With respect to its value at the zero-disorder strength, the maximum conductance value can be as much as 50 % higher. Qualitatively, this can be understood as a result of the dynamical interplay between disorder and Floquet states (channels) generated by light irradiation. Quantitatively, the resonance phenomenon can be explained in the framework of Born theory, where the disorder reorganizes the Floquet Hamiltonian and enhances the effective coupling between the adjacent Floquet conducting channels. That is, disorder is capable of promoting both photon absorption and emission, leading to significant enhancement of nonequilibrium electronic transport. We demonstrate the robustness of the resonance phenomenon by investigating the effects of spatial symmetry breaking on transport and provide an understanding based on analyzing the behavior of the density of states of the Floquet channels.

  19. Enhancement of Otolith Specific Ocular Responses Using Vestibular Stochastic Resonance

    Science.gov (United States)

    Fiedler, Matthew; De Dios, Yiri E.; Esteves, Julie; Galvan, Raquel; Wood, Scott; Bloomberg, Jacob; Mulavara, Ajitkumar

    2011-01-01

    Introduction: Astronauts experience disturbances in sensorimotor function after spaceflight during the initial introduction to a gravitational environment, especially after long-duration missions. Our goal is to develop a countermeasure based on vestibular stochastic resonance (SR) that could improve central interpretation of vestibular input and mitigate these risks. SR is a mechanism by which noise can assist and enhance the response of neural systems to relevant, imperceptible sensory signals. We have previously shown that imperceptible electrical stimulation of the vestibular system enhances balance performance while standing on an unstable surface. Methods: Eye movement data were collected from 10 subjects during variable radius centrifugation (VRC). Subjects performed 11 trials of VRC that provided equivalent tilt stimuli from otolith and other graviceptor input without the normal concordant canal cues. Bipolar stochastic electrical stimulation, in the range of 0-1500 microamperes, was applied to the vestibular system using a constant current stimulator through electrodes placed over the mastoid process behind the ears. In the VRC paradigm, subjects were accelerated to 216 deg./s. After the subjects no longer sensed rotation, the chair oscillated along a track at 0.1 Hz to provide tilt stimuli of 10 deg. Eye movements were recorded for 6 cycles while subjects fixated on a target in darkness. Ocular counter roll (OCR) movement was calculated from the eye movement data during periods of chair oscillations. Results: Preliminary analysis of the data revealed that 9 of 10 subjects showed an average increase of 28% in the magnitude of OCR responses to the equivalent tilt stimuli while experiencing vestibular SR. The signal amplitude at which performance was maximized was in the range of 100-900 microamperes. Discussion: These results indicate that stochastic electrical stimulation of the vestibular system can improve otolith specific responses. This will have a

  20. A non-invasive, quantitative study of broadband spectral responses in human visual cortex.

    Directory of Open Access Journals (Sweden)

    Eline R Kupers

    Full Text Available Currently, non-invasive methods for studying the human brain do not routinely and reliably measure spike-rate-dependent signals, independent of responses such as hemodynamic coupling (fMRI and subthreshold neuronal synchrony (oscillations and event-related potentials. In contrast, invasive methods-microelectrode recordings and electrocorticography (ECoG-have recently measured broadband power elevation in field potentials (~50-200 Hz as a proxy for locally averaged spike rates. Here, we sought to detect and quantify stimulus-related broadband responses using magnetoencephalography (MEG. Extracranial measurements like MEG and EEG have multiple global noise sources and relatively low signal-to-noise ratios; moreover high frequency artifacts from eye movements can be confounded with stimulus design and mistaken for signals originating from brain activity. For these reasons, we developed an automated denoising technique that helps reveal the broadband signal of interest. Subjects viewed 12-Hz contrast-reversing patterns in the left, right, or bilateral visual field. Sensor time series were separated into evoked (12-Hz amplitude and broadband components (60-150 Hz. In all subjects, denoised broadband responses were reliably measured in sensors over occipital cortex, even in trials without microsaccades. The broadband pattern was stimulus-dependent, with greater power contralateral to the stimulus. Because we obtain reliable broadband estimates with short experiments (~20 minutes, and with sufficient signal-to-noise to distinguish responses to different stimuli, we conclude that MEG broadband signals, denoised with our method, offer a practical, non-invasive means for characterizing spike-rate-dependent neural activity for addressing scientific questions about human brain function.

  1. Enhancing spill prevention and response preparedness through quality control techniques

    International Nuclear Information System (INIS)

    Jones, M.A.; Butts, R.L.; Pickering, T.H.; Lindsay, J.R.; McCully, B.S.

    1993-01-01

    The year 1990 saw passage of federal and state oil spill legislation directing the US Environmental Protection Agency and the Florida Department of Environmental Regulation to require on shore bulk petroleum storage facilities to improve their oil spill response and prevention capabilities. The Florida Power ampersand Light Company (FPL), to address concerns arising out of several recent significant spills which had occurred worldwide, and to examine its current situation with regard compliance with the new laws, formed a quality improvement interdepartmental task team in July 1989. Its mission was to reduce the potential for oil spills during waterborne transportation between FPL's fuel oil terminals and its power plants and during transfer and storage of oil at these facilities. Another objective of the team was to enhance the company's spill response preparedness. Using quality control tools and reliability techniques, the team conducted a detailed analysis of seven coastal power plants and five fuel oil terminal facilities. This analysis began with the development of cause-and-effect diagrams designed to identify the root causes of spills so that corrective and preventive actions could be taken. These diagram are constructed by listing possible causes of oil spills under various major categories of possible system breakdown, such as man, method, equipment, and materials. Next, potential root causes are identified and then verified. The team identified the occurrence of surface water oil spill and reduced spill response capability as primary concerns and accordingly constructed cause-and-effect diagrams for both components. Lack of proper procedures, failure of control equipment, and inadequate facility design were identified as potential root causes leading to surface water oil spills. Lack of proper procedures, an inconsistent training program, and response equipment limitations were identified as potential root causes affecting oil spill response capabilities

  2. Which way is up? Asymmetric spectral input along the dorsal-ventral axis influences postural responses in an amphibious annelid.

    Science.gov (United States)

    Jellies, John

    2014-11-01

    Medicinal leeches are predatory annelids that exhibit countershading and reside in aquatic environments where light levels might be variable. They also leave the water and must contend with terrestrial environments. Yet, leeches generally maintain a dorsal upward position despite lacking statocysts. Leeches respond visually to both green and near-ultraviolet (UV) light. I used LEDs to test the hypothesis that ventral, but not dorsal UV would evoke compensatory movements to orient the body. Untethered leeches were tested using LEDs emitting at red (632 nm), green (513 nm), blue (455 nm) and UV (372 nm). UV light evoked responses in 100 % of trials and the leeches often rotated the ventral surface away from it. Visible light evoked no or modest responses (12-15 % of trials) and no body rotation. Electrophysiological recordings showed that ventral sensilla responded best to UV, dorsal sensilla to green. Additionally, a higher order interneuron that is engaged in a variety of parallel networks responded vigorously to UV presented ventrally, and both the visible and UV responses exhibited pronounced light adaptation. These results strongly support the suggestion that a dorsal light reflex in the leech uses spectral comparisons across the dorsal-ventral axis rather than, or in addition to, luminance.

  3. Chronic intrathecal cannulation enhances nociceptive responses in rats

    Directory of Open Access Journals (Sweden)

    Almeida F.R.C.

    2000-01-01

    Full Text Available The influence of a chronically implanted spinal cannula on the nociceptive response induced by mechanical, chemical or thermal stimuli was evaluated. The hyperalgesia in response to mechanical stimulation induced by carrageenin or prostaglandin E2 (PGE2 was significantly increased in cannulated (Cn rats, compared with naive (Nv or sham-operated (Sh rats. Only Cn animals presented an enhanced nociceptive response in the first phase of the formalin test when low doses were used (0.3 and 1%. The withdrawal latency to thermal stimulation of a paw inflamed by carrageenin was significantly reduced in Cn rats but not in Nv or Sh rats. In contrast to Nv and Sh rats, injection in Cn animals of a standard non-steroid anti-inflammatory drug, indomethacin, either intraperitoneally or into the spinal cord via an implanted cannula or by direct puncture of the intrathecal space significantly blocked the intensity of the hyperalgesia induced by PGE2. Cannulated animals treated with indomethacin also showed a significant inhibition of second phase formalin-induced paw flinches. Histopathological analysis of the spinal cord showed an increased frequency of mononuclear inflammatory cells in the Cn groups. Thus, the presence of a chronically implanted cannula seems to cause nociceptive spinal sensitization to mechanical, chemical and thermal stimulation, which can be blocked by indomethacin, thus suggesting that it may result from the spinal release of prostaglandins due to an ongoing mild inflammation.

  4. Response of air stagnation frequency to anthropogenically enhanced radiative forcing

    International Nuclear Information System (INIS)

    Horton, Daniel E; Diffenbaugh, Noah S; Harshvardhan

    2012-01-01

    Stagnant atmospheric conditions can lead to hazardous air quality by allowing ozone and particulate matter to accumulate and persist in the near-surface environment. By changing atmospheric circulation and precipitation patterns, global warming could alter the meteorological factors that regulate air stagnation frequency. We analyze the response of the National Climatic Data Center (NCDC) air stagnation index (ASI) to anthropogenically enhanced radiative forcing using global climate model projections of late-21st century climate change (SRESA1B scenario). Our results indicate that the atmospheric conditions over the highly populated, highly industrialized regions of the eastern United States, Mediterranean Europe, and eastern China are particularly sensitive to global warming, with the occurrence of stagnant conditions projected to increase by 12–25% relative to late-20th century stagnation frequencies (3–18 + days yr −1 ). Changes in the position/strength of the polar jet, in the occurrence of light surface winds, and in the number of precipitation-free days all contribute to more frequent late-21st century air mass stagnation over these high-population regions. In addition, we find substantial inter-model spread in the simulated response of stagnation conditions over some regions using either native or bias corrected global climate model simulations, suggesting that changes in the atmospheric circulation and/or the distribution of precipitation represent important sources of uncertainty in the response of air quality to global warming. (letter)

  5. Responsive copolymers for enhanced petroleum recovery. Annual report

    Energy Technology Data Exchange (ETDEWEB)

    McCormick, C.; Hester, R.

    1994-08-01

    A coordinated research program involving synthesis, characterization, and rheology has been undertaken to develop advanced polymer system which should be significantly more efficient than polymers presently used for mobility control and conformance. Unlike the relatively inefficient, traditional EOR polymers, these advanced polymer systems possess microstructural features responsive to temperature, electrolyte concentration, and shear conditions. Contents of this report include the following chapters. (1) First annual report responsive copolymers for enhanced oil recovery. (2) Copolymers of acrylamide and sodium 3-acrylamido-3-methylbutanoate. (3) Terpolymers of NaAMB, Am, and n-decylacrylamide. (4) Synthesis and characterization of electrolyte responsive terpolymers of acrylamide, N-(4-butyl)phenylacrylamide, and sodium acrylate, sodium-2-acrylamido-2-methylpropanesulphonate or sodium-3-acrylamido-3-methylbutanoate. (5) Synthesis and solution properties of associative acrylamido copolymers with pyrensulfonamide fluorescence labels. (6) Photophysical studies of the solution behavior of associative pyrenesulfonamide-labeled polyacrylamides. (7) Ampholytic copolymers of sodium 2-(acrylamido)-2-methylpropanesulfonate with [2-(acrylamido)-2-methypropyl]trimethylammonium chloride. (8) Ampholytic terpolymers of acrylamide with sodium 2-acrylamido-2-methylpropanesulphoante and 2-acrylamido-2-methylpropanetrimethyl-ammonium chloride and (9) Polymer solution extensional behavior in porous media.

  6. A unified approach for suppressing sidelobes arising in the spectral response of rugate filters

    International Nuclear Information System (INIS)

    Abo-Zahhad, M.; Bataineh, M.

    2000-01-01

    This paper suggests a universal approach to reduce the side lobes which usually appear at both sides of a stop band of a ru gate filter. Both quin tic matching layers and anodization functions are to used to improve the filter's response. The proposed technique could be used to control the ripples level by properly choosing the refractive index profile after amending it to include mat aching layers and/or modulating its profile with a slowly varying anodization (or ta perine) function. Two illustrative examples are given to demonstrate the robustness of the proposed technique. The given examples suggest that combining both effects on the index of refraction profile lead to the lowest possible ripple level. A multichannel filter response is obtained by wavelet cons traction of the refractive index profile with potential applications in multimode lasers and wavelength division multiple xin networks. The obtained results demonstrate the applicability of the adopted approach to design ripple free ru gate filters. The extension to stack filters and other wave guiding structures are also visible. (authors). 14 refs., 8 figs

  7. Enhanced Wireless Power Transmission Using Strong Paramagnetic Response.

    Science.gov (United States)

    Ahn, Dukju; Kiani, Mehdi; Ghovanloo, Maysam

    2014-03-01

    A method of quasi-static magnetic resonant coupling has been presented for improving the power transmission efficiency (PTE) in near-field wireless power transmission, which improves upon the state of the art. The traditional source resonator on the transmitter side is equipped with an additional resonator with a resonance frequency that is tuned substantially higher than the magnetic field excitation frequency. This additional resonator enhances the magnetic dipole moment and the effective permeability of the power transmitter, owing to a phenomenon known as the strong paramagnetic response. Both theoretical calculations and experimental results show increased PTE due to amplification of the effective permeability. In measurements, the PTE was improved from 57.8% to 64.2% at the nominal distance of 15 cm when the effective permeability was 2.6. The power delivered to load was also improved significantly, with the same 10 V excitation voltage, from 0.38 to 5.26 W.

  8. Enhanced Photoelectrochemical Response of Zn-Dotted Hematite

    Directory of Open Access Journals (Sweden)

    Saroj Kumari

    2007-01-01

    Full Text Available Photoelectrochemical response of thin films of α-Fe2O3, Zn doped α-Fe2O3, and Zn dots deposited on doped α-Fe2O3 prepared by spray pyrolysis has been studied. Samples of Zn dots were prepared using thermal evaporation method by evaporating Zn through a mesh having pore diameter of 0.7 mm. The presence of Zn-dotted islands on doped α-Fe2O3 surface exhibited significantly large photocurrent density as compared to other samples. An optimum thickness of Zn dots ∼230 Å is found to give enhanced photoresponse. The observed results are analyzed with the help of estimated values of resistivity, band gap, flatband potential, and donor density.

  9. False-negative contrast-enhanced spectral mammography: use of more than one imaging modality and application of the triple test avoids misdiagnosis.

    Science.gov (United States)

    Taylor, Donna; O'Hanlon, Susan; Latham, Bruce

    2017-03-31

    A 50-year-old woman presented with chest tenderness. On examination, both breasts were lumpy. Bilateral mammography showed heterogeneously dense parenchyma, with possible stromal distortion laterally on the right at the 0900 position. On ultrasound (US), a corresponding 13×9×10 mm irregular hypoechoic mass with internal vascularity was noted and both breasts had a complex heterogeneous fibroglandular background pattern. US-guided core biopsy with marker clip insertion was performed with the diagnosis of a grade 2 invasive ductal carcinoma (IDC). In view of the parenchymal pattern on mammography and US, contrast-enhanced spectral mammography (CESM) was performed for local staging. Mild background enhancement was noted, but there was no enhancement at the lesion site. The patient elected to have bilateral mastectomies and sentinel node biopsies. Final histopathology showed a node negative 11 mm grade 2 oestrogen and progesterone receptor positive, IDC. 2017 BMJ Publishing Group Ltd.

  10. Spectral embedding based active contour (SEAC) for lesion segmentation on breast dynamic contrast enhanced magnetic resonance imaging.

    Science.gov (United States)

    Agner, Shannon C; Xu, Jun; Madabhushi, Anant

    2013-03-01

    Segmentation of breast lesions on dynamic contrast enhanced (DCE) magnetic resonance imaging (MRI) is the first step in lesion diagnosis in a computer-aided diagnosis framework. Because manual segmentation of such lesions is both time consuming and highly susceptible to human error and issues of reproducibility, an automated lesion segmentation method is highly desirable. Traditional automated image segmentation methods such as boundary-based active contour (AC) models require a strong gradient at the lesion boundary. Even when region-based terms are introduced to an AC model, grayscale image intensities often do not allow for clear definition of foreground and background region statistics. Thus, there is a need to find alternative image representations that might provide (1) strong gradients at the margin of the object of interest (OOI); and (2) larger separation between intensity distributions and region statistics for the foreground and background, which are necessary to halt evolution of the AC model upon reaching the border of the OOI. In this paper, the authors introduce a spectral embedding (SE) based AC (SEAC) for lesion segmentation on breast DCE-MRI. SE, a nonlinear dimensionality reduction scheme, is applied to the DCE time series in a voxelwise fashion to reduce several time point images to a single parametric image where every voxel is characterized by the three dominant eigenvectors. This parametric eigenvector image (PrEIm) representation allows for better capture of image region statistics and stronger gradients for use with a hybrid AC model, which is driven by both boundary and region information. They compare SEAC to ACs that employ fuzzy c-means (FCM) and principal component analysis (PCA) as alternative image representations. Segmentation performance was evaluated by boundary and region metrics as well as comparing lesion classification using morphological features from SEAC, PCA+AC, and FCM+AC. On a cohort of 50 breast DCE-MRI studies, Pr

  11. Characterization of Articular Cartilage Recovery and Its Correlation with Optical Response in the Near-Infrared Spectral Range.

    Science.gov (United States)

    Afara, Isaac Oluwaseun; Singh, Sanjleena; Moody, Hayley; Zhang, Lihai; Oloyede, Adekunle

    2017-07-01

    In this study, we examine the capacity of a new parameter, based on the recovery response of articular cartilage, to distinguish between healthy and damaged tissues. We also investigate whether or not this new parameter correlates with the near-infrared (NIR) optical response of articular cartilage. Normal and artificially degenerated (proteoglycan-depleted) bovine cartilage samples were nondestructively probed using NIR spectroscopy. Subsequently they were subjected to a load and unloading protocol, and the recovery response was logged during unloading. The recovery parameter, elastic rebound ( E R ), is based on the strain energy released as the samples underwent instantaneous elastic recovery. Our results reveal positive relationship between the rebound parameter and cartilage proteoglycan content (normal samples: 2.20 ± 0.10 N mm; proteoglycan-depleted samples: 0.50 ± 0.04 N mm for 1 hour of enzymatic treatment and 0.13 ± 0.02 N mm for 4 hours of enzymatic treatment). In addition, multivariate analysis using partial least squares regression was employed to investigate the relationship between E R and NIR spectral data. The results reveal significantly high correlation ( R 2 cal = 98.35% and R 2 val = 79.87%; P cartilage in the combined NIR regions 5,450 to 6,100 cm -1 and 7,500 to 12,500 cm -1 . We conclude that E R can indicate the mechanical condition and state of health of articular cartilage. The correlation of E R with cartilage optical response in the NIR range could facilitate real-time evaluation of the tissue's integrity during arthroscopic surgery and could also provide an important tool for cartilage assessment in tissue engineering and regeneration research.

  12. Study of spectral response of a neutron filter. Design of a method to adjust spectra

    International Nuclear Information System (INIS)

    Colomb-Dolci, F.

    1999-02-01

    The first part of this thesis describes an experimental method which intends to determine a neutron spectrum in the epithermal range [1 eV -10 keV]. Based on measurements of reaction rates provided by activation foils, it gives flux level in each energy range corresponding to each probe. This method can be used in any reactor location or in a neutron beam. It can determine scepter on eight energy groups, five groups in the epithermal range. The second part of this thesis presents a study of an epithermal neutron beam design, in the frame of Neutron Capture Therapy. A beam tube was specially built to test filters made up of different materials. Its geometry was designed to favour epithermal neutron crossing and to cut thermal and fast neutrons. A code scheme was validated to simulate the device response with a Monte Carlo code. Measurements were made at ISIS reactor and experimental spectra were compared to calculated ones. This validated code scheme was used to simulate different materials usable as shields in the tube. A study of these shields is presented at the end of this thesis. (author)

  13. Elastic Properties and Enhanced Piezoelectric Response at Morphotropic Phase Boundaries

    Directory of Open Access Journals (Sweden)

    Francesco Cordero

    2015-12-01

    Full Text Available The search for improved piezoelectric materials is based on the morphotropic phase boundaries (MPB between ferroelectric phases with different crystal symmetry and available directions for the spontaneous polarization. Such regions of the composition x − T phase diagrams provide the conditions for minimal anisotropy with respect to the direction of the polarization, so that the polarization can easily rotate maintaining a substantial magnitude, while the near verticality of the TMPB(x boundary extends the temperature range of the resulting enhanced piezoelectricity. Another consequence of the quasi-isotropy of the free energy is a reduction of the domain walls energies, with consequent formation of domain structures down to nanoscale. Disentangling the extrinsic and intrinsic contributions to the piezoelectricity in such conditions requires a high level of sophistication from the techniques and analyses for studying the structural, ferroelectric and dielectric properties. The elastic characterization is extremely useful in clarifying the phenomenology and mechanisms related to ferroelectric MPBs. The relationship between dielectric, elastic and piezoelectric responses is introduced in terms of relaxation of defects with electric dipole and elastic quadrupole, and extended to the response near phase transitions in the framework of the Landau theory. An account is provided of the anelastic experiments, from torsional pendulum to Brillouin scattering, that provided new important information on ferroelectric MPBs, including PZT, PMN-PT, NBT-BT, BCTZ, and KNN-based systems.

  14. Elastic Properties and Enhanced Piezoelectric Response at Morphotropic Phase Boundaries

    Science.gov (United States)

    Cordero, Francesco

    2015-01-01

    The search for improved piezoelectric materials is based on the morphotropic phase boundaries (MPB) between ferroelectric phases with different crystal symmetry and available directions for the spontaneous polarization. Such regions of the composition x−T phase diagrams provide the conditions for minimal anisotropy with respect to the direction of the polarization, so that the polarization can easily rotate maintaining a substantial magnitude, while the near verticality of the TMPBx boundary extends the temperature range of the resulting enhanced piezoelectricity. Another consequence of the quasi-isotropy of the free energy is a reduction of the domain walls energies, with consequent formation of domain structures down to nanoscale. Disentangling the extrinsic and intrinsic contributions to the piezoelectricity in such conditions requires a high level of sophistication from the techniques and analyses for studying the structural, ferroelectric and dielectric properties. The elastic characterization is extremely useful in clarifying the phenomenology and mechanisms related to ferroelectric MPBs. The relationship between dielectric, elastic and piezoelectric responses is introduced in terms of relaxation of defects with electric dipole and elastic quadrupole, and extended to the response near phase transitions in the framework of the Landau theory. An account is provided of the anelastic experiments, from torsional pendulum to Brillouin scattering, that provided new important information on ferroelectric MPBs, including PZT, PMN-PT, NBT-BT, BCTZ, and KNN-based systems. PMID:28793707

  15. Plasma-Sprayed Titanium Patterns for Enhancing Early Cell Responses

    Science.gov (United States)

    Shi, Yunqi; Xie, Youtao; Pan, Houhua; Zheng, Xuebin; Huang, Liping; Ji, Fang; Li, Kai

    2016-06-01

    Titanium coating has been widely used as a biocompatible metal in biomedical applications. However, the early cell responses and long-term fixation of titanium implants are not satisfied. To obviate these defects, in this paper, micro-post arrays with various widths (150-1000 μm) and intervals (100-300 μm) were fabricated on the titanium substrate by template-assisted plasma spraying technology. In vitro cell culture experiments showed that MC3T3-E1 cells exhibited significantly higher osteogenic differentiation as well as slightly improved adhesion and proliferation on the micro-patterned coatings compared with the traditional one. The cell number on the pattern with 1000 µm width reached 130% after 6 days of incubation, and the expressions of osteopontin (OPN) as well as osteocalcin (OC) were doubled. No obvious difference was found in cell adhesion on various size patterns. The present micro-patterned coatings proposed a new modification method for the traditional plasma spraying technology to enhance the early cell responses and convenience for the bone in-growth.

  16. Contrast Dose and Radiation Dose Reduction in Abdominal Enhanced Computerized Tomography Scans with Single-phase Dual-energy Spectral Computerized Tomography Mode for Children with Solid Tumors.

    Science.gov (United States)

    Yu, Tong; Gao, Jun; Liu, Zhi-Min; Zhang, Qi-Feng; Liu, Yong; Jiang, Ling; Peng, Yun

    2017-04-05

    Contrast dose and radiation dose reduction in computerized tomography (CT) scan for adult has been explored successfully, but there have been few studies on the application of low-concentration contrast in pediatric abdominal CT examinations. This was a feasibility study on the use of dual-energy spectral imaging and adaptive statistical iterative reconstruction (ASiR) for the reduction of radiation dose and iodine contrast dose in pediatric abdominal CT patients with solid tumors. Forty-five patients with solid tumors who had initial CT (Group B) and follow-up CT (Group A) after chemotherapy were enrolled. The initial diagnostic CT scan (Group B) was performed using the standard two-phase enhanced CT with 320 mgI/ml concentration contrast, and the follow-up scan (Group A) was performed using a single-phase enhanced CT at 45 s after the beginning of the 270 mgI/ml contrast injection using spectral mode. Forty percent ASiR was used for the images in Group B and monochromatic images with energy levels ≥60 keV in Group A. In addition, filtered back-projection (FBP) reconstruction was used for monochromatic images hounsfield unit (HU). The abdominal organs of Groups A and B had similar degrees of absolute and relative enhancement (t = 0.36 and -1.716 for liver, -0.153 and -1.546 for pancreas, and 2.427 and 0.866 for renal cortex, all P> 0.05). Signal-to-noise ratio of the abdominal organs was significantly lower in Group A than in Group B (t = -8.11 for liver, -7.83 for pancreas, and -5.38 for renal cortex, all P 3, indicating clinically acceptable image quality. Single-phase, dual-energy spectral CT used for children with solid abdominal tumors can reduce contrast dose and radiation dose and can also maintain clinically acceptable image quality.

  17. Spectral gamuts and spectral gamut mapping

    Science.gov (United States)

    Rosen, Mitchell R.; Derhak, Maxim W.

    2006-01-01

    All imaging devices have two gamuts: the stimulus gamut and the response gamut. The response gamut of a print engine is typically described in CIE colorimetry units, a system derived to quantify human color response. More fundamental than colorimetric gamuts are spectral gamuts, based on radiance, reflectance or transmittance units. Spectral gamuts depend on the physics of light or on how materials interact with light and do not involve the human's photoreceptor integration or brain processing. Methods for visualizing a spectral gamut raise challenges as do considerations of how to utilize such a data-set for producing superior color reproductions. Recent work has described a transformation of spectra reduced to 6-dimensions called LabPQR. LabPQR was designed as a hybrid space with three explicit colorimetric axes and three additional spectral reconstruction axes. In this paper spectral gamuts are discussed making use of LabPQR. Also, spectral gamut mapping is considered in light of the colorimetric-spectral duality of the LabPQR space.

  18. Functional imaging of hemodynamic stimulus response in the rat retina with ultrahigh-speed spectral / Fourier domain OCT

    Science.gov (United States)

    Choi, WooJhon; Baumann, Bernhard; Clermont, Allen C.; Feener, Edward P.; Boas, David A.; Fujimoto, James G.

    2013-03-01

    Measuring retinal hemodynamics in response to flicker stimulus is important for investigating pathophysiology in small animal models of diabetic retinopathy, because a reduction in the hyperemic response is thought to be one of the earliest changes in diabetic retinopathy. In this study, we investigated functional imaging of retinal hemodynamics in response to flicker stimulus in the rat retina using an ultrahigh speed spectral / Fourier domain OCT system at 840nm with an axial scan rate of 244kHz. At 244kHz the nominal axial velocity range that could be measured without phase wrapping was +/-37.7mm/s. Pulsatile total retinal arterial blood flow as a function of time was measured using an en face Doppler approach where a 200μm × 200μm area centered at the central retinal artery was repeatedly raster scanned at a volume acquisition rate of 55Hz. Three-dimensional capillary imaging was performed using speckle decorrelation which has minimal angle dependency compared to other angiography techniques based on OCT phase information. During OCT imaging, a flicker stimulus could be applied to the retina synchronously by inserting a dichroic mirror in the imaging interface. An acute transient increase in total retinal blood flow could be detected. At the capillary level, an increase in the degree of speckle decorrelation in capillary OCT angiography images could also be observed, which indicates an increase in the velocity of blood at the capillary level. This method promises to be useful for the investigation of small animal models of ocular diseases.

  19. Enhancing response coordination through the assessment of response network structural dynamics.

    Directory of Open Access Journals (Sweden)

    Alireza Abbasi

    Full Text Available Preparing for intensifying threats of emergencies in unexpected, dangerous, and serious natural or man-made events, and consequent management of the situation, is highly demanding in terms of coordinating the personnel and resources to support human lives and the environment. This necessitates prompt action to manage the uncertainties and risks imposed by such extreme events, which requires collaborative operation among different stakeholders (i.e., the personnel from both the state and local communities. This research aims to find a way to enhance the coordination of multi-organizational response operations. To do so, this manuscript investigates the role of participants in the formed coordination response network and also the emergence and temporal dynamics of the network. By analyzing an inter-personal response coordination operation to an extreme bushfire event, the networks' and participants' structural change is evaluated during the evolution of the operation network over four time durations. The results reveal that the coordination response network becomes more decentralized over time due to the high volume of communication required to exchange information. New emerging communication structures often do not fit the developed plans, which stress the need for coordination by feedback in addition to by plan. In addition, we find that the participant's brokering role in the response operation network identifies a formal and informal coordination role. This is useful for comparison of network structures to examine whether what really happens during response operations complies with the initial policy.

  20. Characteristics of Spectral Responses for a Ground Motion from Mediterranean Earthquake – ZEGHANGHANE Station (6.3Mw in Morocco, and its Influence on the Structures

    Directory of Open Access Journals (Sweden)

    Ahatri Mohamed

    2018-01-01

    In this case, we determine the spectral response of the ground motion for ZGH station, and study his influence on the structures as well as make a comparison with the requirements of the Moroccan seismic construction regulations (RPS 2000 revised in 2011.

  1. Spectral response modeling and analysis of p–n–p In0.53Ga0.47As/InP HPTs

    International Nuclear Information System (INIS)

    Chen Jun; Lv Jiabing

    2016-01-01

    We report our results on the modeling of the spectral response of the near-infrared (NIR) lattice-matched p–n–p In 0.53 Ga 0.47 As/InP heterojunction phototransistors (HPTs). The spectral response model is developed from the solution of the steady state continuity equations that dominate the excess optically generated minority-carriers in the active regions of the HPTs with accurate boundary conditions. In addition, a detailed optical-power absorption profile is constructed for the device modeling. The calculated responsivity is in good agreement with the measured one for the incident radiation at 980 nm, 1310 nm, and 1550 nm. Furthermore, the variation in the responsivity of the device with the base region width is analyzed. (paper)

  2. Determination of spectral markers of cytotoxicity and genotoxicity using in vitro Raman microspectroscopy: cellular responses to polyamidoamine dendrimer exposure.

    Science.gov (United States)

    Efeoglu, Esen; Casey, Alan; Byrne, Hugh J

    2017-10-09

    Although consumer exposure to nanomaterials is ever increasing, with potential increased applications in areas such as drug and/or gene delivery, contrast agents and diagnosis, the determination of the cyto- and geno-toxic effects of nanomaterials on human health and the environment still remains challenging. Although many techniques have been established and adapted to determine the cytotoxicity and genotoxicity of nano-sized materials, these techniques remain limited by the number of assays required, total cost, and use of labels and they struggle to explain the underlying interaction mechanisms. In this study, Raman microspectroscopy is employed as an in vitro label-free, high content screening technique to observe toxicological changes within the cell in a multi-parametric fashion. The evolution of spectral markers as a function of time and applied dose has been used to elucidate the mechanism of action of polyamidoamine (PAMAM) dendrimers associated with cytotoxicity and their impact on nuclear biochemistry. PAMAM dendrimers are chosen as a model nanomaterial due to their widely studied cytotoxic and genotoxic properties and commercial availability. Point spectra were acquired from the cytoplasm to monitor the cascade of toxic events occurring in the cytoplasm upon nanoparticle exposure, whereas the spectra acquired from the nucleus and the nucleolus were used to explore PAMAM-nuclear material interaction as well as genotoxic responses.

  3. Enhanced tumor responses through therapies combining CCNU, MISO and radiation

    International Nuclear Information System (INIS)

    Siemann, D.W.; Hill, S.A.

    1984-01-01

    Studies were performed to determine whether the radiation sensitizer misonidazole (MISO) could enhance the tumor control probability in a treatment strategy combining radiation and the nitrosourea 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea (CCNU). In initial experiments KHT sarcoma-bearing mice were injected with 1.0 mg/g of MISO simultaneously with a 20 mg/kg dose of CCNU 30-40 min prior to irradiation (1500 rad). With this treatment protocol approximately 60% of the mice were found to be tumor-free 100 days post treatment. By comparison all 2 agent combinations led to 0% cures. To evaluate the relative importance of chemopotentiation versus radiosensitization in the 3 agent protocol, tumors were treated with MISO plus one anti-tumor agent (either radiation of CCNU) and then at times ranging from 0 to 24 hr later exposed to the other agent. When the time between treatments was 0 to 6 hr, a 60 to 80% tumor control rate was achieved for both MISO plus radiation followed by CCNU and MISO plus CCNU followed by radiation. However if the time interval was increased to 18 or 24 hr, the cure rate in the former treatment regimen dropped to 10% while that of the latter remained high at 40%. The data therefore indicate that (1) improved tumor responses may be achieved when MISO is added to a radiation-chemotherapy combination and (2) MISO may be more effective in such a protocol when utilized as a chemopotentiator

  4. WE-DE-207B-04: Quantitative Contrast-Enhanced Spectral Mammography Based On Photon-Counting Detectors: A Feasibility Study

    Energy Technology Data Exchange (ETDEWEB)

    Ding, H; Zhou, B; Beidokhti, D; Molloi, S [University of California, Irvine, CA (United States)

    2016-06-15

    Purpose: To investigate the feasibility of accurate quantification of iodine mass thickness in contrast-enhanced spectral mammography. Methods: Experimental phantom studies were performed on a spectral mammography system based on Si strip photon-counting detectors. Dual-energy images were acquired using 40 kVp and a splitting energy of 34 keV with 3 mm Al pre-filtration. The initial calibration was done with glandular and adipose tissue equivalent phantoms of uniform thicknesses and iodine disk phantoms of various concentrations. A secondary calibration was carried out using the iodine signal obtained from the dual-energy decomposed images and the known background phantom thicknesses and densities. The iodine signal quantification method was validated using phantoms composed of a mixture of glandular and adipose materials, for various breast thicknesses and densities. Finally, the traditional dual-energy weighted subtraction method was also studied as a comparison. The measured iodine signal from both methods was compared to the known iodine concentrations of the disk phantoms to characterize the quantification accuracy. Results: There was good agreement between the iodine mass thicknesses measured using the proposed method and the known values. The root-mean-square (RMS) error was estimated to be 0.2 mg/cm2. The traditional weighted subtraction method also predicted a linear correlation between the measured signal and the known iodine mass thickness. However, the correlation slope and offset values were strongly dependent on the total breast thickness and density. Conclusion: The results of the current study suggest that iodine mass thickness can be accurately quantified with contrast-enhanced spectral mammography. The quantitative information can potentially improve the differentiation between benign and malignant legions. Grant funding from Philips Medical Systems.

  5. WE-DE-207B-04: Quantitative Contrast-Enhanced Spectral Mammography Based On Photon-Counting Detectors: A Feasibility Study

    International Nuclear Information System (INIS)

    Ding, H; Zhou, B; Beidokhti, D; Molloi, S

    2016-01-01

    Purpose: To investigate the feasibility of accurate quantification of iodine mass thickness in contrast-enhanced spectral mammography. Methods: Experimental phantom studies were performed on a spectral mammography system based on Si strip photon-counting detectors. Dual-energy images were acquired using 40 kVp and a splitting energy of 34 keV with 3 mm Al pre-filtration. The initial calibration was done with glandular and adipose tissue equivalent phantoms of uniform thicknesses and iodine disk phantoms of various concentrations. A secondary calibration was carried out using the iodine signal obtained from the dual-energy decomposed images and the known background phantom thicknesses and densities. The iodine signal quantification method was validated using phantoms composed of a mixture of glandular and adipose materials, for various breast thicknesses and densities. Finally, the traditional dual-energy weighted subtraction method was also studied as a comparison. The measured iodine signal from both methods was compared to the known iodine concentrations of the disk phantoms to characterize the quantification accuracy. Results: There was good agreement between the iodine mass thicknesses measured using the proposed method and the known values. The root-mean-square (RMS) error was estimated to be 0.2 mg/cm2. The traditional weighted subtraction method also predicted a linear correlation between the measured signal and the known iodine mass thickness. However, the correlation slope and offset values were strongly dependent on the total breast thickness and density. Conclusion: The results of the current study suggest that iodine mass thickness can be accurately quantified with contrast-enhanced spectral mammography. The quantitative information can potentially improve the differentiation between benign and malignant legions. Grant funding from Philips Medical Systems.

  6. Diagnostic accuracy of contrast-enhanced spectral mammography in comparison to conventional full-field digital mammography in a population of women with dense breasts.

    Science.gov (United States)

    Mori, Miki; Akashi-Tanaka, Sadako; Suzuki, Satoko; Daniels, Murasaki Ikeda; Watanabe, Chie; Hirose, Masanori; Nakamura, Seigo

    2017-01-01

    Contrast-enhanced spectral mammography to compare clinical efficacy of contrast-enhanced spectral mammography (CESM) and conventional digital mammography (MMG) with histopathology as gold standard in dense breasts. A total of 143 breasts of 72 women who underwent CESM and MMG between 2011 and 2014 at Showa University Hospital were analyzed. 129 (90.2 %) of 143 breasts revealed dense breasts on MMG. 58 (40.6 %) of 143 breasts were diagnosed with breast cancer at histopathology. The remaining 85 breasts were diagnosed with benign findings after image assessments and/or core needle biopsy. CESM revealed 8 false-negative cases among 58 breast cancer cases (sensitivity 86.2 %) and 5 false-positive cases (specificity 94.1 %). Accuracy was 90.9 %. Conventional MMG was assessed true positive in 31 of 58 breast cancer cases (sensitivity 53.4 %) and false positive in 12 cases (specificity 85.9 %). Accuracy was 72.7 %. Sensitivity (p < 0.001), specificity (p = 0.016) and accuracy (p < 0.001) were significantly higher on CESM compared to MMG. MMG missed malignancy in 27 breasts. Of these, 25 were dense breasts. Of these 25, 20 (80.0 %) breasts were positive on CESM. These findings suggest that CESM offers superior clinical performance compared to MMG. Use of CESM may decrease false negatives especially for women with dense breasts.

  7. A calibration method for the measurement of IR detector spectral responses using a FTIR spectrometer equipped with a DTGS reference cell

    Science.gov (United States)

    Gravrand, Olivier; Wlassow, J.; Bonnefond, L.

    2014-07-01

    Various high performance IR detectors are today available on the market from QWIPs to narrow gap semiconductor photodiodes, which exhibit various spectral features. In the astrophysics community, the knowledge of the detector spectral shape is of first importance. This quantity (spectral QE or response) is usually measured by means of a monochromator followed by an integrating sphere and compared to a calibrated reference detector. This approach is usually very efficient in the visible range, where all optical elements are very well known, particularly the reference detector. This setup is also widely used in the near IR (up to 3μm) but as the wavelength increases, it becomes less efficient. For instance, the internal emittance of integrating spheres in the IR, and the bad knowledge of reference detectors for longer wavelengths tend to degrade the measurement reliability. Another approach may therefore be considered, using a Fourier transform IR spectrometer (FTIR). In this case, as opposed to the monochromator, the tested detector is not in low flux condition, the incident light containing a mix of different wavelengths. Therefore, the reference detector has to be to be sensitive (and known) in the whole spectral band of interest, because it will sense all those wavelengths at the same time. A popular detector used in this case is a Deuterated Triglycine Sulfate thermal detector (DTGS). Being a pyro detetector, the spectral response of such a detector is very flat, mainly limited by its window. However, the response of such a detector is very slow, highly depending on the temporal frequency of the input signal. Moreover, being a differential detector, it doesn't work in DC. In commercial FTIR spectrometers, the source luminance is usually continuously modulated by the moving interferometer, and the result is that the interferogram mixes optical spectral information (optical path difference) and temporal variations (temporal frequency) so that the temporal

  8. Characterization of Lactococcus lactis response to ampicillin and ciprofloxacin using surface-enhanced Raman spectroscopy.

    Science.gov (United States)

    Wang, Panxue; Pang, Shintaro; Zhang, Hua; Fan, Mingtao; He, Lili

    2016-01-01

    Decades of antibiotic use or misuse has resulted in antibiotic resistance in lactic acid bacteria, a group of common culture starters and probiotic microorganisms. This has urged researchers to study how lactic acid bacteria respond to antibiotics, so as to have a better strategy to identify and predict the antibiotic-resistant bacteria. This study aimed to characterize the biochemical profiles of Lactococcus lactis responding to antibiotics using surface-enhanced Raman spectroscopy (SERS). Lactococcus lactis exposed to antibiotics was mixed with 50-nm gold nanoparticles for subsequent SERS measurements. The SERS spectra analyzed by principal component analysis showed no significant change after 30 min of antibiotic treatment, whereas distinct changes were clearly observed after 60 and 90 min of antibiotic treatment. Different antibiotics induced different spectral changes, and these changes revealed the detailed biochemical information of cellular responses. This study demonstrates that the SERS method developed not only senses the changes in the bacterial cell wall, but also reveals details of the biochemical profiles, which help us to understand how lactic acid bacteria respond to antibiotics, as well as to set a base for the detection of antibiotic susceptibility of bacteria by SERS.

  9. MO-FG-CAMPUS-IeP1-01: Alternative K-Edge Filters for Low-Energy Image Acquisition in Contrast Enhanced Spectral Mammography

    Energy Technology Data Exchange (ETDEWEB)

    Shrestha, S; Vedantham, S; Karellas, A [University of Massachusetts Medical School, Worcester, MA (United States)

    2016-06-15

    Purpose: In Contrast Enhanced Spectral Mammography (CESM), Rh filter is often used during low-energy image acquisition. The potential for using Ag, In and Sn filters, which exhibit K-edge closer to, and just below that of Iodine, instead of the Rh filter, was investigated for the low-energy image acquisition. Methods: Analytical computations of the half-value thickness (HVT) and the photon fluence per mAs (photons/mm2/mAs) for 50µm Rh were compared with other potential K-edge filters (Ag, In and Sn), all with K-absorption edge below that of Iodine. Two strategies were investigated: fixed kVp and filter thickness (50µm for all filters) resulting in HVT variation, and fixed kVp and HVT resulting in variation in Ag, In and Sn thickness. Monte Carlo simulations (GEANT4) were conducted to determine if the scatter-to-primary ratio (SPR) and the point spread function of scatter (scatter PSF) differed between Rh and other K-edge filters. Results: Ag, In and Sn filters (50µm thick) increased photon fluence/mAs by 1.3–1.4, 1.8–2, and 1.7–2 at 28-32 kVp compared to 50µm Rh, which could decrease exposure time. Additionally, the fraction of spectra closer to and just below Iodine’s K-edge increased with these filters, which could improve post-subtraction image contrast. For HVT matched to 50µm Rh filtered spectra, the thickness range for Ag, In, and Sn were (41,44)µm, (49,55)µm and (45,53)µm, and increased photon fluence/mAs by 1.5–1.7, 1.6–2, and 1.6–2.2, respectively. Monte Carlo simulations showed that neither the SPR nor the scatter PSF of Ag, In and Sn differed from Rh, indicating no additional detriment due to x-ray scatter. Conclusion: The use of Ag, In and Sn filters for low-energy image acquisition in CESM is potentially feasible and could decrease exposure time and may improve post-subtraction image contrast. Effect of these filters on radiation dose, contrast, noise and associated metrics are being investigated. Funding Support: Supported in

  10. Combined FVTD/PSTD Schemes with Enhanced Spectral Accuracy for the Design of Large-Scale EMC Applications

    Directory of Open Access Journals (Sweden)

    N. V. Kantartzis

    2012-10-01

    Full Text Available A generalized conformal time-domain method with adjustable spectral accuracy is introduced in this paper for the consistent analysis of large-scale electromagnetic compatibility problems. The novel 3-D hybrid schemes blend a stencil-optimized finite-volume time-domain and a multimodal Fourier-Chebyshev pseudo-spectral time-domain algorithm that split the overall space into smaller and flexible areas. A key asset is that both techniques are updated independently and interconnected by robust boundary conditions. Also, combining a family of spatial derivative approximators with controllable precision in general curvilinear coordinates, the proposed method launches a conformal field flux formulation to derive electromagnetic quantities in regions with fine details. For advanced grid reliability at dissimilar media interfaces, dispersion-reduced adaptive operators, which assign the proper weights to each spatial increment, are developed. So, the resulting discretization yields highly rigorous and computationally affordable simulations, devoid of lattice errors. Numerical results, addressing detailed comparisons of various realistic applications with reference or measurement data verify our methodology and reveal its significant applicability.

  11. From ultraviolet to Prussian blue: a spectral response for the cyanotype process and a safe educational activity to explain UV exposure for all ages.

    Science.gov (United States)

    Turner, J; Parisi, A V; Downs, N; Lynch, M

    2014-12-01

    Engaging students and the public in understanding UV radiation and its effects is achievable using the real time experiment that incorporates blueprint paper, an "educational toy" that is a safe and easy demonstration of the cyanotype chemical process. The cyanotype process works through the presence of UV radiation. The blueprint paper was investigated to be used as not only engagement in discussion for public outreach about UV radiation, but also as a practical way to introduce the exploration of measurement of UV radiation exposure and as a consequence, digital image analysis. Tests of print methods and experiments, dose response, spectral response and dark response were investigated. Two methods of image analysis for dose response calculation are provided using easy to access software and two methods of pixel count analysis were used to determine spectral response characteristics. Variation in manufacture of the blueprint paper product indicates some variance between measurements. Most importantly, as a result of this investigation, a preliminary spectral response range for the radiation required to produce the cyanotype reaction is presented here, which has until now been unknown.

  12. Is contrast-enhanced spectral mammography (CESM) helpful in differentiating diabetic mastopathy from breast carcinoma?

    Science.gov (United States)

    Travieso Aja, María Del Mar; Santana López, Gloria; Rodríguez Rodríguez, Mario; Luzardo, Octavio P

    2016-10-01

    Diabetic mastopathy (DM) is a rare benign inflammatory disease of the breast, which nevertheless gives suspicious image of malignancy by breast ultrasound and mammography. MRI studies of this disease have indicated both nonspecific enhancement and non-enhancement of the lesion, depending on its degree of lymphocytic infiltration. This is the first case report discussing the appearances of DM on CESM, a novel mammographic technique. © 2016 The Royal Australian and New Zealand College of Radiologists.

  13. Dynamic Response and Simulations of Nanoparticle-Enhanced Composites

    National Research Council Canada - National Science Library

    Mantena, P. R; Al-Ostaz, Ahmed; Cheng, Alexander H

    2007-01-01

    ...) molecular dynamics simulations of nanoparticle-enhanced composites and fly- ash based foams that are being considered for the future generation naval structures or retrofitting of existing ones...

  14. Structural Changes of Desertified and Managed Shrubland Landscapes in Response to Drought: Spectral, Spatial and Temporal Analyses

    Directory of Open Access Journals (Sweden)

    Tarin Paz-Kagan

    2014-08-01

    Full Text Available Drought events cause changes in ecosystem function and structure by reducing the shrub abundance and expanding the biological soil crusts (biocrusts. This change increases the leakage of nutrient resources and water into the river streams in semi-arid areas. A common management solution for decreasing this loss of resources is to create a runoff-harvesting system (RHS. The objective of the current research is to apply geo-information techniques, including remote sensing and geographic information systems (GIS, on the watershed scale, to monitor and analyze the spatial and temporal changes in response to drought of two source-sink systems, the natural shrubland and the human-made RHSs in the semi-arid area of the northern Negev Desert, Israel. This was done by evaluating the changes in soil, vegetation and landscape cover. The spatial changes were evaluated by three spectral indices: Normalized Difference Vegetation Index (NDVI, Crust Index (CI and landscape classification change between 2003 and 2010. In addition, we examined the effects of environmental factors on NDVI, CI and their clustering after successive drought years. The results show that vegetation cover indicates a negative ∆NDVI change due to a reduction in the abundance of woody vegetation. On the other hand, the soil cover change data indicate a positive ∆CI change due to the expansion of the biocrusts. These two trends are evidence for degradation processes in terms of resource conservation and bio-production. A considerable part of the changed area (39% represents transitions between redistribution processes of resources, such as water, sediments, nutrients and seeds, on the watershed scale. In the pre-drought period, resource redistribution mainly occurred on the slope scale, while in the post-drought period, resource redistribution occurred on the whole watershed scale. However, the RHS management is effective in reducing leakage, since these systems are located on the

  15. Biomechanics of the cornea evaluated by spectral analysis of waveforms from ocular response analyzer and Corvis-ST.

    Directory of Open Access Journals (Sweden)

    Sushma Tejwani

    Full Text Available In this study, spectral analysis of the deformation signal from Corvis-ST (CoST and reflected light intensity from ocular response analyzer (ORA was performed to evaluate biomechanical concordance with each other.The study was non-interventional, observational, cross-sectional and involved 188 eyes from 94 normal subjects. Three measurements were made on each eye with ORA and CoST each and then averaged for each device. The deformation signal from CoST and reflected light intensity (applanation signal from ORA was compiled for all the eyes. The ORA signal was inverted about a line joining the two applanation peaks. All the signals were analyzed with Fourier series. The area under the signal curves (AUC, root mean square (RMS of all the harmonics, lower order (LO included 1st and 2nd order harmonic, higher order (HO up to 6th harmonic, CoST deformation amplitude (DA, corneal hysteresis (CH and corneal resistance factor (CRF were analyzed.The device variables and those calculated by Fourier transform were statistically significantly different between CoST and ORA. These variables also differed between the eyes of the same subject. There was also statistically significant influence of eyes (left vs. right on the differences in a sub-set of RMS variables only. CH and CRF differed statistically significantly between the eyes of subject (p<0.001 but not DA (p = 0.65.CoST was statistically significantly different from ORA. CoST may be useful in delineating true biomechanical differences between the eyes of a subject as it reports deformation.

  16. The use of wavelength-selective plastic cladding materials in horticulture: understanding of crop and fungal responses through the assessment of biological spectral weighting functions.

    Science.gov (United States)

    Paul, Nigel D; Jacobson, Rob J; Taylor, Anna; Wargent, Jason J; Moore, Jason P

    2005-01-01

    Plant responses to light spectral quality can be exploited to deliver a range of agronomically desirable end points in protected crops. This can be achieved using plastics with specific spectral properties as crop covers. We have studied the responses of a range of crops to plastics that have either (a) increased transmission of UV compared with standard horticultural covers, (b) decreased transmission of UV or (c) increased the ratio of red (R) : far-red (FR) radiation. Both the UV-transparent and R : FR increasing films reduced leaf area and biomass, offering potential alternatives to chemical growth regulators. The UV-opaque film increased growth, but while this may be useful in some crops, there were trade-offs with elements of quality, such as pigmentation and taste. UV manipulation may also influence disease control. Increasing UV inhibited not only the pathogenic fungus Botrytis cinerea but also the disease biocontrol agent Trichoderma harzianum. Unlike B. cinerea, T. harzianum was highly sensitive to UV-A radiation. These fungal responses and those for plant growth in the growth room and the field under different plastics are analyzed in terms of alternative biological spectral weighting functions (BSWF). The role of BSWF in assessing general patterns of response to UV modification in horticulture is also discussed.

  17. Enhanced optical transmission through a star-shaped bull's eye at dual resonant-bands in UV and the visible spectral range.

    Science.gov (United States)

    Nazari, Tavakol; Khazaeinezhad, Reza; Jung, Woohyun; Joo, Boram; Kong, Byung-Joo; Oh, Kyunghwan

    2015-07-13

    Dual resonant bands in UV and the visible range were simultaneously observed in the enhanced optical transmission (EOT) through star-shaped plasmonic structures. EOTs through four types of polygonal bull's eyes with a star aperture surrounded by the concentric star grooves were analyzed and compared for 3, 4, 5, and 6 corners, using finite difference time domain (FDTD) method. In contrast to plasmonic resonances in the visible range, the UV-band resonance intensity was found to scale with the number of corners, which is related with higher order multipole interactions. Spectral positions and relative intensities of the dual resonances were analyzed parametrically to find optimal conditions to maximize EOT in UV-visible dual bands.

  18. Performance enhancement of successive interference cancellation scheme based on spectral amplitude coding for optical code-division multiple-access systems using Hadamard codes

    Science.gov (United States)

    Eltaif, Tawfig; Shalaby, Hossam M. H.; Shaari, Sahbudin; Hamarsheh, Mohammad M. N.

    2009-04-01

    A successive interference cancellation scheme is applied to optical code-division multiple-access (OCDMA) systems with spectral amplitude coding (SAC). A detailed analysis of this system, with Hadamard codes used as signature sequences, is presented. The system can easily remove the effect of the strongest signal at each stage of the cancellation process. In addition, simulation of the prose system is performed in order to validate the theoretical results. The system shows a small bit error rate at a large number of active users compared to the SAC OCDMA system. Our results reveal that the proposed system is efficient in eliminating the effect of the multiple-user interference and in the enhancement of the overall performance.

  19. Plant growth enhancement and associated physiological responses are coregulated by ethylene and gibberellin in response to harpin protein Hpa1

    OpenAIRE

    Li, Xiaojie; Han, Bing; Xu, Manyu; Han, Liping; Zhao, Yanying; Liu, Zhilan; Dong, Hansong; Zhang, Chunling

    2014-01-01

    The harpin protein Hpa1 produced by the bacterial blight pathogen of rice induces several growth-promoting responses in plants, activating the ethylene signaling pathway, increasing photosynthesis rates and EXPANSIN (EXP) gene expression levels, and thereby enhancing the vegetative growth. This study was attempted to analyze any mechanistic connections among the above and the role of gibberellin in these responses. Hpa1-induced growth enhancement was evaluated in Arabidopsis, tomato, and rice...

  20. Excitation mechanisms in 1 mJ picosecond laser induced low pressure He plasma and the resulting spectral quality enhancement

    Energy Technology Data Exchange (ETDEWEB)

    Idris, Nasrullah; Lahna, Kurnia; Abdulmadjid, Syahrun Nur [Department of Physics, Faculty of Mathematics and Natural Sciences, Syiah Kuala University, Darussalam, Banda Aceh 23111, NAD (Indonesia); Ramli, Muliadi [Department of Chemistry, Faculty of Mathematics and Natural Sciences, Syiah Kuala University, Darussalam, Banda Aceh 23111, NAD (Indonesia); Suyanto, Hery [Department of Physics, Faculty of Mathematics and Natural Sciences, Udayana University, Kampus Bukit Jimbaran, Denpasar 80361, Bali (Indonesia); Marpaung, Alion Mangasi [Department of Physics, Faculty of Mathematics and Natural Sciences, Jakarta State University, 10 Rawamangun, Jakarta (Indonesia); Pardede, Marincan [Department of Electrical Engineering, University of Pelita Harapan, 1100 M.H. Thamrin Boulevard, Lippo Village, Tangerang 15811 (Indonesia); Jobiliong, Eric [Department of Industrial Engineering, University of Pelita Harapan, 1100 M.H. Thamrin Boulevard, Lippo Village, Tangerang 15811 (Indonesia); Hedwig, Rinda; Lie, Zener Sukra [Department of Computer Engineering, Bina Nusantara University, 9 K.H. Syahdan, Jakarta 14810 (Indonesia); Research Center of Maju Makmur Mandiri Foundation, 40/80 Srengseng Raya, Jakarta 11630 (Indonesia); Suliyanti, Maria Margaretha [Research Center for Physics, Indonesia Institute of Sciences, Kawasan PUSPIPTEK, Serpong, Tangerang Selatan 15314, Banten (Indonesia); Lie, Tjung Jie; Kurniawan, Koo Hendrik, E-mail: kurnia18@cbn.net.id [Research Center of Maju Makmur Mandiri Foundation, 40/80 Srengseng Raya, Jakarta 11630 (Indonesia); Kagawa, Kiichiro [Fukui Science Education Academy, Takagi Chuou 2 choume, Fukui 910-0804 (Japan); Tjia, May On [Research Center of Maju Makmur Mandiri Foundation, 40/80 Srengseng Raya, Jakarta 11630 (Indonesia); Physics of Magnetism and Photonics Group, Faculty of Mathematics and Natural Sciences, Bandung Institute of Technology, 10 Ganesha, Bandung 40132 (Indonesia)

    2015-06-14

    We report in this paper the results of an experimental study on the spectral and dynamical characteristics of plasma emission induced by 1 mJ picoseconds (ps) Nd-YAG laser using spatially resolved imaging and time resolved measurement of the emission intensities of copper sample. This study has provided the experimental evidence concerning the dynamical characteristics of the excitation mechanisms in various stages of the plasma formation, which largely consolidate the basic scenarios of excitation processes commonly accepted so far. However, it is also clearly shown that the duration of the shock wave excitation process induced by ps laser pulses is much shorter than those observed in laser induced breakdown spectroscopy employing nanosecond laser at higher output energy. This allows the detection of atomic emission due exclusively to He assisted excitation in low pressure He plasma by proper gating of the detection time. Furthermore, the triplet excited state associated with He I 587.6 nm is shown to be the one most likely involved in the process responsible for the excellent spectral quality as evidenced by its application to spectrochemical analysis of a number of samples. The use of very low energy laser pulses also leads to minimal destructive effect marked by the resulted craters of merely about 10 μm diameter and only 10 nm deep. It is especially noteworthy that the excellent emission spectrum of deuterium detected from D-doped titanium sample is free of spectral interference from the undesirable ubiquitous water molecules without a precleaning procedure as applied previously and yielding an impressive detection limit of less than 10 μg/g. Finally, the result of this study also shows a promising application to depth profiling of impurity distribution in the sample investigated.

  1. The auditory enhancement effect is not reflected in the 80-Hz auditory steady-state response.

    Science.gov (United States)

    Carcagno, Samuele; Plack, Christopher J; Portron, Arthur; Semal, Catherine; Demany, Laurent

    2014-08-01

    The perceptual salience of a target tone presented in a multitone background is increased by the presentation of a precursor sound consisting of the multitone background alone. It has been proposed that this "enhancement" phenomenon results from an effective amplification of the neural response to the target tone. In this study, we tested this hypothesis in humans, by comparing the auditory steady-state response (ASSR) to a target tone that was enhanced by a precursor sound with the ASSR to a target tone that was not enhanced. In order to record neural responses originating in the brainstem, the ASSR was elicited by amplitude modulating the target tone at a frequency close to 80 Hz. The results did not show evidence of an amplified neural response to enhanced tones. In a control condition, we measured the ASSR to a target tone that, instead of being perceptually enhanced by a precursor sound, was acoustically increased in level. This level increase matched the magnitude of enhancement estimated psychophysically with a forward masking paradigm in a previous experimental phase. We found that the ASSR to the tone acoustically increased in level was significantly greater than the ASSR to the tone enhanced by the precursor sound. Overall, our results suggest that the enhancement effect cannot be explained by an amplified neural response at the level of the brainstem. However, an alternative possibility is that brainstem neurons with enhanced responses do not contribute to the scalp-recorded ASSR.

  2. Body enhancement : body images, vulnerability and moral responsibility

    NARCIS (Netherlands)

    den Dikken, A.

    2011-01-01

    The objective of this explorative study is to show that it is highly relevant to integrate cultural and personal body images into the ethical debate on human enhancement. The current debate has little attention for the motivations to make use of technology to alter the human body, such as cultural

  3. Clinical utility of contrast-enhanced spectral mammography as an adjunct for tomosynthesis-detected architectural distortion.

    Science.gov (United States)

    Patel, Bhavika K; Naylor, Michelle E; Kosiorek, Heidi E; Lopez-Alvarez, Yania M; Miller, Adrian M; Pizzitola, Victor J; Pockaj, Barbara A

    Supplement tomosynthesis-detected architectural distortions (AD) with CESM to better characterize malignant vs benign lesions. Retrospective review CESM prior to biopsied AD. Pathology: benign, radial scar, or malignant. 49 lesions (45 patients). 29 invasive cancers, 1 DCIS (range, 0.4-4.7cm); 9 radial scars; 10 benign. 37 (75.5%) ADs had associated enhancement. PPV 78.4% (29/37), sensitivity 96.7% (29/30); specificity, 57.9% (11/19); NPV, 91.7% (11/12). False-positive rate 21.6% (8/37); false-negative rate, 8.3% (1/12). Accuracy 81.6% (40/49). High sensitivity and NPV of CESM in patients with AD is promising as an adjunct tool in diagnosing malignancy and avoiding unnecessary biopsy, respectively. Copyright © 2017 Elsevier Inc. All rights reserved.

  4. Considering Affective Responses towards Environments for Enhancing Location Based Services

    Science.gov (United States)

    Huang, H.; Gartner, G.; Klettner, S.; Schmidt, M.

    2014-04-01

    A number of studies in the field of environmental psychology show that humans perceive and evaluate their surroundings affectively. Some places are experienced as unsafe, while some others as attractive and interesting. Experiences from daily life show that many of our daily behaviours and decision-making are often influenced by this kind of affective responses towards environments. Location based services (LBS) are often designed to assist and support people's behaviours and decision-making in space. In order to provide services with high usefulness (usability and utility), LBS should consider these kinds of affective responses towards environments. This paper reports on the results of a research project, which studies how people's affective responses towards environments can be modelled and acquired, as well as how LBS can benefit by considering these affective responses. As one of the most popular LBS applications, mobile pedestrian navigation systems are used as an example for illustration.

  5. Defining response capacity to enhance climate change policy

    International Nuclear Information System (INIS)

    Tompkins, Emma L.; Neil Adger, W.

    2005-01-01

    Climate change adaptation and mitigation decisions made by governments are usually taken in different policy domains. At the individual level however, adaptation and mitigation activities are undertaken together as part of the management of risk and resources. We propose that a useful starting point to develop a national climate policy is to understand what societal response might mean in practice. First we frame the set of responses at the national policy level as a trade off between investment in the development and diffusion of new technology, and investment in encouraging and enabling society to change its behaviour and or adopt the new technology. We argue that these are the pertinent trade-offs, rather than those usually posited between climate change mitigation and adaptation. The preference for a policy response that focuses more on technological innovation rather than one that focuses on changing social behaviour will be influenced by the capacity of different societies to change their greenhouse gas emissions; by perceived vulnerability to climate impacts; and by capacity to modify social behaviour and physical environment. Starting with this complete vision of response options should enable policy makers to re-evaluate the risk environment and the set of response options available to them. From here, policy makers should consider who is responsible for making climate response decisions and when actions should be taken. Institutional arrangements dictate social and political acceptability of different policies, they structure worldviews, and they determine the provision of resources for investment in technological innovation and social change. The importance of focussing on the timing of the response is emphasised to maximise the potential for adjustments through social learning and institutional change at different policy scales. We argue that the ability to respond to climate change is both enabled and constrained by social and technological conditions

  6. Numerical analysis of the harmonic components of the Bragg wavelength content in spectral responses of apodized fiber Bragg gratings written by means of a phase mask with a variable phase step height.

    Science.gov (United States)

    Osuch, Tomasz

    2016-02-01

    The influence of the complex interference patterns created by a phase mask with variable diffraction efficiency in apodized fiber Bragg grating (FBGs) formation on their reflectance spectra is studied. The effect of the significant contributions of the zeroth and higher (m>±1) diffraction orders on the Bragg wavelength peak and its harmonic components is analyzed numerically. The results obtained for Gaussian and tanh apodization profiles are compared with similar data calculated for a uniform grating. It is demonstrated that when an apodized FBG is written using a phase mask with variable diffraction efficiency, significant enhancement of the harmonic components and a reduction of the Bragg wavelength peak in the grating spectral response are observed. This is particularly noticeable for the Gaussian apodization profile due to the substantial contributions of phase mask sections with relatively small phase steps in the FBG formation.

  7. Enhanced spectral resolution by high-dimensional NMR using the filter diagonalization method and “hidden” dimensions

    Science.gov (United States)

    Meng, Xi; Nguyen, Bao D.; Ridge, Clark; Shaka, A. J.

    2009-01-01

    High-dimensional (HD) NMR spectra have poorer digital resolution than low-dimensional (LD) spectra, for a fixed amount of experiment time. This has led to “reduced-dimensionality” strategies, in which several LD projections of the HD NMR spectrum are acquired, each with higher digital resolution; an approximate HD spectrum is then inferred by some means. We propose a strategy that moves in the opposite direction, by adding more time dimensions to increase the information content of the data set, even if only a very sparse time grid is used in each dimension. The full HD time-domain data can be analyzed by the Filter Diagonalization Method (FDM), yielding very narrow resonances along all of the frequency axes, even those with sparse sampling. Integrating over the added dimensions of HD FDM NMR spectra reconstitutes LD spectra with enhanced resolution, often more quickly than direct acquisition of the LD spectrum with a larger number of grid points in each of the fewer dimensions. If the extra dimensions do not appear in the final spectrum, and are used solely to boost information content, we propose the moniker hidden-dimension NMR. This work shows that HD peaks have unmistakable frequency signatures that can be detected as single HD objects by an appropriate algorithm, even though their patterns would be tricky for a human operator to visualize or recognize, and even if digital resolution in an HD FT spectrum is very coarse compared with natural line widths. PMID:18926747

  8. Analysis of Cross-Seasonal Spectral Response from Kettle Holes: Application of Remote Sensing Techniques for Chlorophyll Estimation

    Directory of Open Access Journals (Sweden)

    Bernd Lennartz

    2012-11-01

    Full Text Available Kettle holes, small inland water bodies usually less than 1 ha in size, are subjected to pollution, drainage, and structural alteration by intensive land use practices. This study presents the analysis of spectral signatures from kettle holes based on in situ water sampling and reflectance measurements in application for chlorophyll estimation. Water samples and surface reflectance from kettle holes were collected from 6 ponds in 15 field campaigns (5 in 2007 and 10 in 2008, resulting in a total of 80 spectral datasets. We assessed the existing semi-empirical algorithms to determine chlorophyll content for different types of kettle holes using seasonal and cross-seasonal volume reflectance and derivative spectra. Based on this analysis and optical properties of water leaving reflectance from kettle holes, the following typology of the remote signal interpretation was proposed: Submerged vegetation, Phytoplankton dominated and Mixed type.

  9. Plant growth enhancement and associated physiological responses are coregulated by ethylene and gibberellin in response to harpin protein Hpa1.

    Science.gov (United States)

    Li, Xiaojie; Han, Bing; Xu, Manyu; Han, Liping; Zhao, Yanying; Liu, Zhilan; Dong, Hansong; Zhang, Chunling

    2014-04-01

    The harpin protein Hpa1 produced by the bacterial blight pathogen of rice induces several growth-promoting responses in plants, activating the ethylene signaling pathway, increasing photosynthesis rates and EXPANSIN (EXP) gene expression levels, and thereby enhancing the vegetative growth. This study was attempted to analyze any mechanistic connections among the above and the role of gibberellin in these responses. Hpa1-induced growth enhancement was evaluated in Arabidopsis, tomato, and rice. And growth-promoting responses were determined mainly as an increase of chlorophyll a/b ratio, which indicates a potential elevation of photosynthesis rates, and enhancements of photosynthesis and EXP expression in the three plant species. In Arabidopsis, Hpa1-induced growth-promoting responses were partially compromised by a defect in ethylene perception or gibberellin biosynthesis. In tomato and rice, compromises of Hpa1-induced growth-promoting responses were caused by a pharmacological treatment with an ethylene perception inhibitor or a gibberellin biosynthesis inhibitor. In the three plant species, moreover, Hpa1-induced growth-promoting responses were significantly impaired, but not totally eliminated, by abolishing ethylene perception or gibberellin synthesis. However, simultaneous nullifications in both ethylene perception and gibberellin biosynthesis almost canceled the full effects of Hpa1 on plant growth, photosynthesis, and EXP2 expression. Theses results suggest that ethylene and gibberellin coregulate Hpa1-induced plant growth enhancement and associated physiological and molecular responses.

  10. Analysis of petroleum contaminated soils by spectral modeling and pure response profile recovery of n-hexane

    International Nuclear Information System (INIS)

    Chakraborty, Somsubhra; Weindorf, David C.; Li, Bin; Ali, Md. Nasim; Majumdar, K.; Ray, D.P.

    2014-01-01

    This pilot study compared penalized spline regression (PSR) and random forest (RF) regression using visible and near-infrared diffuse reflectance spectroscopy (VisNIR DRS) derived spectra of 164 petroleum contaminated soils after two different spectral pretreatments [first derivative (FD) and standard normal variate (SNV) followed by detrending] for rapid quantification of soil petroleum contamination. Additionally, a new analytical approach was proposed for the recovery of the pure spectral and concentration profiles of n-hexane present in the unresolved mixture of petroleum contaminated soils using multivariate curve resolution alternating least squares (MCR-ALS). The PSR model using FD spectra (r 2  = 0.87, RMSE = 0.580 log 10  mg kg −1 , and residual prediction deviation = 2.78) outperformed all other models tested. Quantitative results obtained by MCR-ALS for n-hexane in presence of interferences (r 2  = 0.65 and RMSE 0.261 log 10  mg kg −1 ) were comparable to those obtained using FD (PSR) model. Furthermore, MCR ALS was able to recover pure spectra of n-hexane. - Highlights: • We predicted soil petroleum contamination with VisNIR DRS spectra. • We examined 2 spectral pretreatments and 2 multivariate models. • MCR-ALS was used for compositional and spectral resolution of n-hexane. • Penalized spline regression performed best for quantifying soil TPH. • MCR-ALS was promising for resolution of complex soil–petroleum mixture. - Use of VisNIR DRS for rapid quantification of soil TPH and resolution of complex soil petroleum mixtures

  11. Estimation of spectral kurtosis

    Science.gov (United States)

    Sutawanir

    2017-03-01

    Rolling bearings are the most important elements in rotating machinery. Bearing frequently fall out of service for various reasons: heavy loads, unsuitable lubrications, ineffective sealing. Bearing faults may cause a decrease in performance. Analysis of bearing vibration signals has attracted attention in the field of monitoring and fault diagnosis. Bearing vibration signals give rich information for early detection of bearing failures. Spectral kurtosis, SK, is a parameter in frequency domain indicating how the impulsiveness of a signal varies with frequency. Faults in rolling bearings give rise to a series of short impulse responses as the rolling elements strike faults, SK potentially useful for determining frequency bands dominated by bearing fault signals. SK can provide a measure of the distance of the analyzed bearings from a healthy one. SK provides additional information given by the power spectral density (psd). This paper aims to explore the estimation of spectral kurtosis using short time Fourier transform known as spectrogram. The estimation of SK is similar to the estimation of psd. The estimation falls in model-free estimation and plug-in estimator. Some numerical studies using simulations are discussed to support the methodology. Spectral kurtosis of some stationary signals are analytically obtained and used in simulation study. Kurtosis of time domain has been a popular tool for detecting non-normality. Spectral kurtosis is an extension of kurtosis in frequency domain. The relationship between time domain and frequency domain analysis is establish through power spectrum-autocovariance Fourier transform. Fourier transform is the main tool for estimation in frequency domain. The power spectral density is estimated through periodogram. In this paper, the short time Fourier transform of the spectral kurtosis is reviewed, a bearing fault (inner ring and outer ring) is simulated. The bearing response, power spectrum, and spectral kurtosis are plotted to

  12. Vs30 and spectral response from collocated shallow, active- and passive-source Vs data at 27 sites in Puerto Rico

    Science.gov (United States)

    Odum, Jack K.; Stephenson, William J.; Williams, Robert A.; von Hillebrandt-Andrade, Christa

    2013-01-01

    Shear‐wave velocity (VS) and time‐averaged shear‐wave velocity to 30 m depth (VS30) are the key parameters used in seismic site response modeling and earthquake engineering design. Where VS data are limited, available data are often used to develop and refine map‐based proxy models of VS30 for predicting ground‐motion intensities. In this paper, we present shallow VS data from 27 sites in Puerto Rico. These data were acquired using a multimethod acquisition approach consisting of noninvasive, collocated, active‐source body‐wave (refraction/reflection), active‐source surface wave at nine sites, and passive‐source surface‐wave refraction microtremor (ReMi) techniques. VS‐versus‐depth models are constructed and used to calculate spectral response plots for each site. Factors affecting method reliability are analyzed with respect to site‐specific differences in bedrock VS and spectral response. At many but not all sites, body‐ and surface‐wave methods generally determine similar depths to bedrock, and it is the difference in bedrock VS that influences site amplification. The predicted resonant frequencies for the majority of the sites are observed to be within a relatively narrow bandwidth of 1–3.5 Hz. For a first‐order comparison of peak frequency position, predictive spectral response plots from eight sites are plotted along with seismograph instrument spectra derived from the time series of the 16 May 2010 Puerto Rico earthquake. We show how a multimethod acquisition approach using collocated arrays compliments and corroborates VS results, thus adding confidence that reliable site characterization information has been obtained.

  13. Local field enhanced second-harmonic response of organic nanofibers

    DEFF Research Database (Denmark)

    Leißner, Till; Kostiučenko, Oksana; Fiutowski, Jacek

    Organic CNHP4 nanofibers showing a strong second-harmonic (SH) response have been successfully implemented as active components in a metal-organic hybrid system. Using nondestructive roll-on transfer technique nanofibers were transferred from the growing mica substrates onto electron...

  14. Do Fraternities and Sororities Enhance Socially Responsible Leadership?

    Science.gov (United States)

    Martin, Georgianna L.; Hevel, Michael S.; Pascarella, Ernest T.

    2012-01-01

    This study explored the effects of fraternity and sorority membership on first-year college students' development of socially responsible leadership at 24 colleges and universities. The institutions varied in terms of public versus private, size, region, and student residential patterns. Results showed that fraternity members demonstrated…

  15. Power transformation for enhancing responsiveness of quality of life questionnaire.

    Science.gov (United States)

    Zhou, YanYan Ange

    2015-01-01

    We investigate the effect of power transformation of raw scores on the responsiveness of quality of life survey. The procedure maximizes the paired t-test value on the power transformed data to obtain an optimal power range. The parallel between the Box-Cox transformation is also investigated for the quality of life data.

  16. Enhancement of defense responses by oligandrin against Botrytis ...

    African Journals Online (AJOL)

    Oligandrin is an elicitin-like protein with a molecular mass of ∼10 kDa secreted by Pythium oligandrum. Here, the effect of oligandrin on defense response against Botrytis cinerea in tomato leaves is reported. Tomato seedlings were pretreated with 5 ml oligandrin (10 g/ml) by root submerging and then inoculated with B.

  17. Carica Papaya Seed Extract Enhances Cellular Response to Stress ...

    African Journals Online (AJOL)

    Therefore, the present study was carried out to investigate the role of Carica papaya seed (CPS) extract that contains, Benzyl Isothiocyanates, one of the inducers of phase II enzymes in the regulation of cellular stress. The cellular responses were observed in U937 cells (human monocyte/macrophage cell line) at the ...

  18. Enhancement of broiler performance and immune response by ...

    African Journals Online (AJOL)

    Administrator

    2011-09-19

    Sep 19, 2011 ... response by Echinacea purpurea supplemented in diet. Saied Habibian ... E. purpurea, animal and human studies have shown that. E. purpurea had .... claimed that E. purpurea extract as a feed additive for broilers and layers is .... Echinacea: biological effects and active principles, In: Phytomedicines of ...

  19. Oral antibiotics enhance antibody responses to keyhole limpet hemocyanin in orally but not muscularly immunized chickens.

    Science.gov (United States)

    Murai, Atsushi; Kitahara, Kazuki; Okumura, Shouta; Kobayashi, Misato; Horio, Fumihiko

    2016-02-01

    Recent studies have emphasized the crucial role of gut microbiota in triggering and modulating immune response. We aimed to determine whether the modification of gut microbiota by oral co-administration of two antibiotics, ampicillin and neomycin, would lead to changes in the antibody response to antigens in chickens. Neonatal chickens were given or not given ampicillin and neomycin (0.25 and 0.5 g/L, respectively) in drinking water. At 2 weeks of age, the chicks were muscularly or orally immunized with antigenic keyhole limpet hemocyanin (KLH), and then serum anti-KLH antibody levels were examined by ELISA. In orally immunized chicks, oral antibiotics treatment enhanced antibody responses (IgM, IgA, IgY) by 2-3-fold compared with the antibiotics-free control, while the antibiotics did not enhance antibody responses in the muscularly immunized chicks. Concomitant with their enhancement of antibody responses, the oral antibiotics also lowered the Lactobacillus species in feces. Low doses of antibiotics (10-fold and 100-fold lower than the initial trial), which failed to change the fecal Lactobacillus population, did not modify any antibody responses when chicks were orally immunized with KLH. In conclusion, oral antibiotics treatment enhanced the antibody response to orally exposed antigens in chickens. This enhancement of antibody response was associated with a modification of the fecal Lactobacillus content, suggesting a possible link between gut microbiota and antibody response in chickens. © 2015 Japanese Society of Animal Science.

  20. Enhancing load-following and/or spectral shift capability in single-sparger natural circulation boiling water reactors

    International Nuclear Information System (INIS)

    Oosterkamp, W.J.

    1992-01-01

    This patent describes a method for obtaining load-following capability in a coiling water reactor (BWR) wherein housed within a reactor pressure vessel (RPV) is a nuclear core disposed within a shroud having a shroud head and which with the RPV defines an annulus region disposed beneath the nuclear core, an upper steam dome connected to a steam outlet in the RPV, a core upper plenum formed within the shroud head and disposed atop the nuclear core, a chimney mounted atop the shroud head and in fluid communication with the core upper plenum and with a steam separator having a skirt which is in fluid communication with the steam dome, the region outside of the chimney defining a downcomer region, there being a water level established therein under normal operation of the BWR, and the RPV containing a feedwater inlet. It comprises: disposing a single sparger connected to the feedwater inlet above the steam separator skirt bottom about the interior circumference of the RPV at an elevation at approximately the water level established during normal operation of the BWR; and adjusting the feedwater flow through the inlet and into the sparger to vary the water level to be above, at or below the elevational location of the sparger in response to load-following need

  1. Middle atmosphere response to different descriptions of the 11-yr solar cycle in spectral irradiance in a chemistry-climate model

    Directory of Open Access Journals (Sweden)

    W. H. Swartz

    2012-07-01

    Full Text Available The 11-yr solar cycle in solar spectral irradiance (SSI inferred from measurements by the SOlar Radiation & Climate Experiment (SORCE suggests a much larger variation in the ultraviolet than previously accepted. We present middle atmosphere ozone and temperature responses to the solar cycles in SORCE SSI and the ubiquitous Naval Research Laboratory (NRL SSI reconstruction using the Goddard Earth Observing System chemistry-climate model (GEOSCCM. The results are largely consistent with other recent modeling studies. The modeled ozone response is positive throughout the stratosphere and lower mesosphere using the NRL SSI, while the SORCE SSI produces a response that is larger in the lower stratosphere but out of phase with respect to total solar irradiance above 45 km. The modeled responses in total ozone are similar to those derived from satellite and ground-based measurements, 3–6 Dobson Units per 100 units of 10.7-cm radio flux (F10.7 in the tropics. The peak zonal mean tropical temperature response using the SORCE SSI is nearly 2 K per 100 units F10.7 – 3 times larger than the simulation using the NRL SSI. The GEOSCCM and the Goddard Space Flight Center (GSFC 2-D coupled model are used to examine how the SSI solar cycle affects the atmosphere through direct solar heating and photolysis processes individually. Middle atmosphere ozone is affected almost entirely through photolysis, whereas the solar cycle in temperature is caused both through direct heating and photolysis feedbacks, processes that are mostly linearly separable. This is important in that it means that chemistry-transport models should simulate the solar cycle in ozone well, while general circulation models without coupled chemistry will underestimate the temperature response to the solar cycle significantly in the middle atmosphere. Further, the net ozone response results from the balance of ozone production at wavelengths less than 242 nm

  2. Enhancing nuclear emergency response through international co-operation

    International Nuclear Information System (INIS)

    Ugletveit, F.; Aaltonen, H.

    2003-01-01

    Full text: A large number of different national plans and procedures have been established and substantial resources allocated world wide with varying comprehensiveness and quality depending an the national requirements and the possible threat scenarios considered. These national plans are only to a small degree harmonized. It is clear that it is the responsibility of the authorities in the respective countries or utilities under their jurisdiction, to decide upon and implement appropriate response actions to a nuclear emergency. The basic needs for responding properly are: infrastructure in terms of plans, procedures etc.; information regarding the accident, its development and consequences; resources in terms of expertise, man power and tools for acquiring and processing information, making assessments and decisions and carry out the actions. When a large number of countries are making assessments and decisions for their own country and providing the public with information, it is important that assessments, decisions and public information become correct, complete and consistent across boarders. In order to achieve this, they should all have access to the same information as basis for their actions. Lack of information or wrong information could easily lead to wrong assessments, wrong decisions and misleading information to the public. If there is a serious nuclear emergency somewhere that could potentially affect several or many States in one way or another, 'everyone' would like to know 'everything' that happens 'everywhere'. In this case, all States should have the obligation to share with the international community the relevant information they have available themselves and that could be of interest for other States responding to the situation. During a serious nuclear or radiological emergency, the demand for different kinds of resources is huge and could, in many countries, probably exceed national capabilities. Looking at the situation in a global

  3. Enhancing wellbeing of employees through corporate social responsibility context

    Directory of Open Access Journals (Sweden)

    Dežmar-Krainz Karmen

    2015-01-01

    Full Text Available During last 25 years technological development has accelerated the globalization process which has caused dramatic changes within and across organization. Business performance is varying, complex, global and is changing faster than ever before. over the time, society expectations have changed, changes have affected customers, partners and employees as well. In order to retain on the global market, organizations integrate corporate social responsibility into their business performance with the objective to reinforce their competitiveness. In the knowledge economy, where knowledge is a significant resource and the demand for more highly skilled workers has increased, employees became the most important and in fact the only remaining realistic challenge of competitive ability. Workplace wellbeing refers to mental, psychological or emotional aspect of employee's life. The awareness of management on the employees' wellbeing which takes into consideration the employees satisfaction, health and professional development is an effective approach in strengthening of an organizational performance. The aim of this paper is to analyze and assess how socially responsible orientation also incorporated in strategic human resource management can contribute to the achievement of wellbeing of employees. Strategic management of human resources includes the necessary coordination between various employees' health and performance aspects. This contributes to the balance between private and working life. Social responsible activities coordinated through strategic human resource management significantly influence the employees' wellbeing as well as competitiveness of the organization. .

  4. Spectral stratigraphy

    Science.gov (United States)

    Lang, Harold R.

    1991-01-01

    A new approach to stratigraphic analysis is described which uses photogeologic and spectral interpretation of multispectral remote sensing data combined with topographic information to determine the attitude, thickness, and lithology of strata exposed at the surface. The new stratigraphic procedure is illustrated by examples in the literature. The published results demonstrate the potential of spectral stratigraphy for mapping strata, determining dip and strike, measuring and correlating stratigraphic sequences, defining lithofacies, mapping biofacies, and interpreting geological structures.

  5. Enhanced subliminal emotional responses to dynamic facial expressions

    Directory of Open Access Journals (Sweden)

    Wataru eSato

    2014-09-01

    Full Text Available Emotional processing without conscious awareness plays an important role in human social interaction. Several behavioral studies reported that subliminal presentation of photographs of emotional facial expressions induces unconscious emotional processing. However, it was difficult to elicit strong and robust effects using this method. We hypothesized that dynamic presentations of facial expressions would enhance subliminal emotional effects and tested this hypothesis with two experiments. Fearful or happy facial expressions were presented dynamically or statically in either the left or the right visual field for 20 (Experiment 1 and 30 (Experiment 2 ms. Nonsense target ideographs were then presented, and participants reported their preference for them. The results consistently showed that dynamic presentations of emotional facial expressions induced more evident emotional biases toward subsequent targets than did static ones. These results indicate that dynamic presentations of emotional facial expressions induce more evident unconscious emotional processing.

  6. Attention enhances contrast appearance via increased input baseline of neural responses.

    Science.gov (United States)

    Cutrone, Elizabeth K; Heeger, David J; Carrasco, Marisa

    2014-12-30

    Covert spatial attention increases the perceived contrast of stimuli at attended locations, presumably via enhancement of visual neural responses. However, the relation between perceived contrast and the underlying neural responses has not been characterized. In this study, we systematically varied stimulus contrast, using a two-alternative, forced-choice comparison task to probe the effect of attention on appearance across the contrast range. We modeled performance in the task as a function of underlying neural contrast-response functions. Fitting this model to the observed data revealed that an increased input baseline in the neural responses accounted for the enhancement of apparent contrast with spatial attention. © 2014 ARVO.

  7. Enhancing Natural Killer Cell Mediated Targeting and Responses to Myeloid Leukemias

    Science.gov (United States)

    2017-10-01

    AWARD NUMBER: W81XWH-16-1-0380 TITLE: Enhancing Natural Killer Cell Mediated Targeting and Responses to Myeloid Leukemias PRINCIPAL...2017 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER Enhancing Natural Killer Cell Mediated Targeting and Responses to Myeloid Leukemias 5b. GRANT NUMBER...leukemias still have poor prognosis, particularly in the elderly, and require hematopoietic cell transplants to fully kill the tumor, which is both

  8. Activity enhances dopaminergic long-duration response in Parkinson disease

    Science.gov (United States)

    Auinger, Peggy; Fahn, Stanley; Oakes, David; Shoulson, Ira; Kieburtz, Karl; Rudolph, Alice; Marek, Kenneth; Seibyl, John; Lang, Anthony; Olanow, C. Warren; Tanner, Caroline; Schifitto, Giovanni; Zhao, Hongwei; Reyes, Lydia; Shinaman, Aileen; Comella, Cynthia L.; Goetz, Christopher; Blasucci, Lucia M.; Samanta, Johan; Stacy, Mark; Williamson, Kelli; Harrigan, Mary; Greene, Paul; Ford, Blair; Moskowitz, Carol; Truong, Daniel D.; Pathak, Mayank; Jankovic, Joseph; Ondo, William; Atassi, Farah; Hunter, Christine; Jacques, Carol; Friedman, Joseph H.; Lannon, Margaret; Russell, David S.; Jennings, Danna; Fussell, Barbara; Standaert, David; Schwarzschild, Michael A.; Growdon, John H.; Tennis, Marsha; Gauthier, Serge; Panisset, Michel; Hall, Jean; Gancher, Stephen; Hammerstad, John P.; Stone, Claudia; Alexander-Brown, Barbara; Factor, Stewart A.; Molho, Eric; Brown, Diane; Evans, Sharon; Clark, Jeffrey; Manyam, Bala; Simpson, Patricia; Wulbrecht, Brian; Whetteckey, Jacqueline; Martin, Wayne; Roberts, Ted; King, Pamela; Hauser, Robert; Zesiewicz, Theresa; Gauger, Lisa; Trugman, Joel; Wooten, G. Frederick; Rost-Ruffner, Elke; Perlmutter, Joel; Racette, Brad A.; Suchowersky, Oksana; Ranawaya, Ranjit; Wood, Susan; Pantella, Carol; Kurlan, Roger; Richard, Irene; Pearson, Nancy; Caviness, John N.; Adler, Charles; Lind, Marlene; Simuni, Tanya; Siderowf, Andrew; Colcher, Amy; Lloyd, Mary; Weiner, William; Shulman, Lisa; Koller, William; Lyons, Kelly; Feldman, Robert G.; Saint-Hilaire, Marie H.; Ellias, Samuel; Thomas, Cathi-Ann; Juncos, Jorge; Watts, Ray; Partlow, Anna; Tetrud, James; Togasaki, Daniel M.; Stewart, Tracy; Mark, Margery H.; Sage, Jacob I.; Caputo, Debbie; Gould, Harry; Rao, Jayaraman; McKendrick, Ann; Brin, Mitchell; Danisi, Fabio; Benabou, Reina; Hubble, Jean; Paulson, George W.; Reider, Carson; Birnbaum, Alex; Miyasaki, Janis; Johnston, Lisa; So, Julie; Pahwa, Rajesh; Dubinsky, Richard M.; Wszolek, Zbigniew; Uitti, Ryan; Turk, Margaret; Tuite, Paul; Rottenberg, David; Hansen, Joy; Ramos, Serrano; Waters, Cheryl; Lew, Mark; Welsh, Mickie; Kawai, Connie; O'Brien, Christopher; Kumar, Rajeev; Seeberger, Lauren; Judd, Deborah; Barclay, C. Lynn; Grimes, David A.; Sutherland, Laura; Dawson, Ted; Reich, Stephen; Dunlop, Rebecca; Albin, Roger; Frey, Kirk; Wernette, Kristine; Fahn, Stanley; Oakes, David; Shoulson, Ira; Kieburtz, Karl; Rudolph, Alice; Marek, Kenneth; Seibyl, John; Lang, Anthony; Olanow, C. Warren; Tanner, Caroline; Schifitto, Giovanni; Zhao, Hongwei; Reyes, Lydia; Shinaman, Aileen; Comella, Cynthia L.; Goetz, Christopher; Blasucci, Lucia M.; Samanta, Johan; Stacy, Mark; Williamson, Kelli; Harrigan, Mary; Greene, Paul; Ford, Blair; Moskowitz, Carol; Truong, Daniel D.; Pathak, Mayank; Jankovic, Joseph; Ondo, William; Atassi, Farah; Hunter, Christine; Jacques, Carol; Friedman, Joseph H.; Lannon, Margaret; Russell, David S.; Jennings, Danna; Fussell, Barbara; Standaert, David; Schwarzschild, Michael A.; Growdon, John H.; Tennis, Marsha; Gauthier, Serge; Panisset, Michel; Hall, Jean; Gancher, Stephen; Hammerstad, John P.; Stone, Claudia; Alexander-Brown, Barbara; Factor, Stewart A.; Molho, Eric; Brown, Diane; Evans, Sharon; Clark, Jeffrey; Manyam, Bala; Simpson, Patricia; Wulbrecht, Brian; Whetteckey, Jacqueline; Martin, Wayne; Roberts, Ted; King, Pamela; Hauser, Robert; Zesiewicz, Theresa; Gauger, Lisa; Trugman, Joel; Wooten, G. Frederick; Rost-Ruffner, Elke; Perlmutter, Joel; Racette, Brad A.; Suchowersky, Oksana; Ranawaya, Ranjit; Wood, Susan; Pantella, Carol; Kurlan, Roger; Richard, Irene; Pearson, Nancy; Caviness, John N.; Adler, Charles; Lind, Marlene; Simuni, Tanya; Siderowf, Andrew; Colcher, Amy; Lloyd, Mary; Weiner, William; Shulman, Lisa; Koller, William; Lyons, Kelly; Feldman, Robert G.; Saint-Hilaire, Marie H.; Ellias, Samuel; Thomas, Cathi-Ann; Juncos, Jorge; Watts, Ray; Partlow, Anna; Tetrud, James; Togasaki, Daniel M.; Stewart, Tracy; Mark, Margery H.; Sage, Jacob I.; Caputo, Debbie; Gould, Harry; Rao, Jayaraman; McKendrick, Ann; Brin, Mitchell; Danisi, Fabio; Benabou, Reina; Hubble, Jean; Paulson, George W.; Reider, Carson; Birnbaum, Alex; Miyasaki, Janis; Johnston, Lisa; So, Julie; Pahwa, Rajesh; Dubinsky, Richard M.; Wszolek, Zbigniew; Uitti, Ryan; Turk, Margaret; Tuite, Paul; Rottenberg, David; Hansen, Joy; Ramos, Serrano; Waters, Cheryl; Lew, Mark; Welsh, Mickie; Kawai, Connie; O'Brien, Christopher; Kumar, Rajeev; Seeberger, Lauren; Judd, Deborah; Barclay, C. Lynn; Grimes, David A.; Sutherland, Laura; Dawson, Ted; Reich, Stephen; Dunlop, Rebecca; Albin, Roger; Frey, Kirk; Wernette, Kristine; Mendis, Tilak

    2012-01-01

    Objective: We tested the hypothesis that dopamine-dependent motor learning mechanism underlies the long-duration response to levodopa in Parkinson disease (PD) based on our studies in a mouse model. By data-mining the motor task performance in dominant and nondominant hands of the subjects in a double-blind randomized trial of levodopa therapy, the effects of activity and dopamine therapy were examined. Methods: We data-mined the Earlier versus Later Levodopa Therapy in Parkinson's Disease (ELLDOPA) study published in 2005 and performed statistical analysis comparing the effects of levodopa and dominance of handedness over 42 weeks. Results: The mean change in finger-tapping counts from baseline before the initiation of therapy to predose at 9 weeks and 40 weeks increased more in the dominant compared to nondominant hand in levodopa-treated subjects in a dose-dependent fashion. There was no significant difference in dominant vs nondominant hands in the placebo group. The short-duration response assessed by the difference of postdose performance compared to predose performance at the same visit did not show any significant difference between dominant vs nondominant hands. Conclusions: Active use of the dominant hand and dopamine replacement therapy produces synergistic effect on long-lasting motor task performance during “off” medication state. Such effect was confined to dopamine-responsive symptoms and not seen in dopamine-resistant symptoms such as gait and balance. We propose that long-lasting motor learning facilitated by activity and dopamine is a form of disease modification that is often seen in trials of medications that have symptomatic effects. PMID:22459675

  9. Enhancement of the spectral selectivity of complex samples by measuring them in a frozen state at low temperatures in order to improve accuracy for quantitative analysis. Part II. Determination of viscosity for lube base oils using Raman spectroscopy.

    Science.gov (United States)

    Kim, Mooeung; Chung, Hoeil

    2013-03-07

    The use of selectivity-enhanced Raman spectra of lube base oil (LBO) samples achieved by the spectral collection under frozen conditions at low temperatures was effective for improving accuracy for the determination of the kinematic viscosity at 40 °C (KV@40). A collection of Raman spectra from samples cooled around -160 °C provided the most accurate measurement of KV@40. Components of the LBO samples were mainly long-chain hydrocarbons with molecular structures that were deformable when these were frozen, and the different structural deformabilities of the components enhanced spectral selectivity among the samples. To study the structural variation of components according to the change of sample temperature from cryogenic to ambient condition, n-heptadecane and pristane (2,6,10,14-tetramethylpentadecane) were selected as representative components of LBO samples, and their temperature-induced spectral features as well as the corresponding spectral loadings were investigated. A two-dimensional (2D) correlation analysis was also employed to explain the origin for the improved accuracy. The asynchronous 2D correlation pattern was simplest at the optimal temperature, indicating the occurrence of distinct and selective spectral variations, which enabled the variation of KV@40 of LBO samples to be more accurately assessed.

  10. Analysis of multi-layered films. [determining dye densities by applying a regression analysis to the spectral response of the composite transparency

    Science.gov (United States)

    Scarpace, F. L.; Voss, A. W.

    1973-01-01

    Dye densities of multi-layered films are determined by applying a regression analysis to the spectral response of the composite transparency. The amount of dye in each layer is determined by fitting the sum of the individual dye layer densities to the measured dye densities. From this, dye content constants are calculated. Methods of calculating equivalent exposures are discussed. Equivalent exposures are a constant amount of energy over a limited band-width that will give the same dye content constants as the real incident energy. Methods of using these equivalent exposures for analysis of photographic data are presented.

  11. Assessing and Enhancing Health Care Providers’ Response to Domestic Violence

    Directory of Open Access Journals (Sweden)

    Tuija Leppäkoski

    2014-01-01

    Full Text Available This study aimed to examine possible changes from 2008 to 2012 in the skills of health care staff in identifying and intervening in domestic violence (DV. A longitudinal descriptive study design with volunteer samples (baseline; n=68, follow-up; n=100 was used to acquire information regarding the present state and needs of the staff in practices related to DV. The results of the baseline survey were used as a basis for planning two interventions: staff training and drafting practical guidelines. Information was collected by questionnaires from nurses, physicians, and social workers and supplemented by responses from the interviews. The data were analysed using both quantitative and qualitative methods. A chi-square test was used to test the statistical significance of the data sets. In addition, participants’ quotes are used to describe specific phenomena or issues. The comparison showed that overall a small positive change had taken place between the study periods. However, the participants were aware of their own shortcomings in identifying and intervening in DV. Changes happen slowly, and administrative support is needed to sustain such changes. Therefore, this paper offers recommendations to improve health care providers’ response to DV. Moreover, there is a great need for evaluating the training programme used.

  12. Evaluation of low-energy contrast-enhanced spectral mammography images by comparing them to full-field digital mammography using EUREF image quality criteria.

    Science.gov (United States)

    Lalji, U C; Jeukens, C R L P N; Houben, I; Nelemans, P J; van Engen, R E; van Wylick, E; Beets-Tan, R G H; Wildberger, J E; Paulis, L E; Lobbes, M B I

    2015-10-01

    Contrast-enhanced spectral mammography (CESM) examination results in a low-energy (LE) and contrast-enhanced image. The LE appears similar to a full-field digital mammogram (FFDM). Our aim was to evaluate LE CESM image quality by comparing it to FFDM using criteria defined by the European Reference Organization for Quality Assured Breast Screening and Diagnostic Services (EUREF). A total of 147 cases with both FFDM and LE images were independently scored by two experienced radiologists using these (20) EUREF criteria. Contrast detail measurements were performed using a dedicated phantom. Differences in image quality scores, average glandular dose, and contrast detail measurements between LE and FFDM were tested for statistical significance. No significant differences in image quality scores were observed between LE and FFDM images for 17 out of 20 criteria. LE scored significantly lower on one criterion regarding the sharpness of the pectoral muscle (p < 0.001), and significantly better on two criteria on the visualization of micro-calcifications (p = 0.02 and p = 0.034). Dose and contrast detail measurements did not reveal any physical explanation for these observed differences. Low-energy CESM images are non-inferior to FFDM images. From this perspective FFDM can be omitted in patients with an indication for CESM. • Low-energy CESM images are non-inferior to FFDM images. • Micro-calcifications are significantly more visible on LE CESM than on FFDM. • There is no physical explanation for this improved visibility of micro-calcifications. • There is no need for an extra FFDM when CESM is indicated.

  13. Study on spectral parameters and the support vector machine in surface enhanced Raman spectroscopy of serum for the detection of colon cancer

    International Nuclear Information System (INIS)

    Li, Xiaozhou; Yang, Tianyue; Yao, Jun; Wang, Deli; Li, Siqi; Song, Youtao; Ding, Jianhua

    2015-01-01

    Surface enhanced Raman spectroscopy (SERS) has been recognized as an effective tool for the analysis of tissue samples and biofluids. In this work, a total of 27 spectral parameters were chosen and compared using SERS. Four parameters with the highest prediction ability were selected for further support vector machine (SVM) analysis. As a comparison, principal component analysis (PCA) was used on the same dataset for feature extraction. SVM was used with the above two data reduction methods separately to differentiate colon cancer and the control groups. Serum taken from 52 colon cancer patients and 60 healthy volunteers were collected and tested by SERS. The accuracy for Parameter-SVM was 95.0%, the sensitivity was 96.2%, and the specificity was 95.5%, which was much higher than the results using only one parameter, while for PCA-SVM, the results are 93.3%, 92.3%, and 92.9%, respectively. These results demonstrate that the SERS analysis method can be used to identify serum differences between colon cancer patients and normal people. (letter)

  14. Accuracy of contrast-enhanced spectral mammography for estimating residual tumor size after neoadjuvant chemotherapy in patients with breast cancer: a feasibility study.

    Science.gov (United States)

    Barra, Filipe Ramos; de Souza, Fernanda Freire; Camelo, Rosimara Eva Ferreira Almeida; Ribeiro, Andrea Campos de Oliveira; Farage, Luciano

    2017-01-01

    To assess the feasibility of contrast-enhanced spectral mammography (CESM) of the breast for assessing the size of residual tumors after neoadjuvant chemotherapy (NAC). In breast cancer patients who underwent NAC between 2011 and 2013, we evaluated residual tumor measurements obtained with CESM and full-field digital mammography (FFDM). We determined the concordance between the methods, as well as their level of agreement with the pathology. Three radiologists analyzed eight CESM and FFDM measurements separately, considering the size of the residual tumor at its largest diameter and correlating it with that determined in the pathological analysis. Interobserver agreement was also evaluated. The sensitivity, specificity, positive predictive value, and negative predictive value were higher for CESM than for FFDM (83.33%, 100%, 100%, and 66% vs. 50%, 50%, 50%, and 25%, respectively). The CESM measurements showed a strong, consistent correlation with the pathological findings (correlation coefficient = 0.76-0.92; intraclass correlation coefficient = 0.692-0.886). The correlation between the FFDM measurements and the pathological findings was not statistically significant, with questionable consistency (intraclass correlation coefficient = 0.488-0.598). Agreement with the pathological findings was narrower for CESM measurements than for FFDM measurements. Interobserver agreement was higher for CESM than for FFDM (0.94 vs. 0.88). CESM is a feasible means of evaluating residual tumor size after NAC, showing a good correlation and good agreement with pathological findings. For CESM measurements, the interobserver agreement was excellent.

  15. Accuracy of contrast-enhanced spectral mammography for estimating residual tumor size after neoadjuvant chemotherapy in patients with breast cancer: a feasibility study

    Directory of Open Access Journals (Sweden)

    Filipe Ramos Barra

    Full Text Available Abstract Objective: To assess the feasibility of contrast-enhanced spectral mammography (CESM of the breast for assessing the size of residual tumors after neoadjuvant chemotherapy (NAC. Materials and methods: In breast cancer patients who underwent NAC between 2011 and 2013, we evaluated residual tumor measurements obtained with CESM and full-field digital mammography (FFDM. We determined the concordance between the methods, as well as their level of agreement with the pathology. Three radiologists analyzed eight CESM and FFDM measurements separately, considering the size of the residual tumor at its largest diameter and correlating it with that determined in the pathological analysis. Interobserver agreement was also evaluated. Results: The sensitivity, specificity, positive predictive value, and negative predictive value were higher for CESM than for FFDM (83.33%, 100%, 100%, and 66% vs. 50%, 50%, 50%, and 25%, respectively. The CESM measurements showed a strong, consistent correlation with the pathological findings (correlation coefficient = 0.76-0.92; intraclass correlation coefficient = 0.692-0.886. The correlation between the FFDM measurements and the pathological findings was not statistically significant, with questionable consistency (intraclass correlation coefficient = 0.488-0.598. Agreement with the pathological findings was narrower for CESM measurements than for FFDM measurements. Interobserver agreement was higher for CESM than for FFDM (0.94 vs. 0.88. Conclusion: CESM is a feasible means of evaluating residual tumor size after NAC, showing a good correlation and good agreement with pathological findings. For CESM measurements, the interobserver agreement was excellent.

  16. Enhanced photoanisotropic response in azopolymer doped with elongated goethite nanoparticles

    International Nuclear Information System (INIS)

    Nedelchev, L; Nazarova, D; Berberova, N; Mateev, G; Kostadinova, D; Mariño-Fernández, R; Salgueiriño, V; Schmool, D

    2016-01-01

    We present a study of the photoinduced birefringence in nanocomposite films of an azopolymer (PAZO) doped with goethite (a-FeOOH, a characteristic antiferromagnetic material) nanoparticles (NPs). The NPs had an elongated shape with a size 15×150 nm, i.e., a ratio of 1:10. Samples were prepared with different concentrations of the NPs in the azopolymer varying from 0% (undoped azopolymer film) to 15 wt %. An unusual dependence of the birefringence on the concentration was observed - two peaks of enhancement at 1 % and at 10 % concentration. Our previous studies on ZnO and SiO 2 NP have indicated only one peak of increase at low concentrations - 0.5 wt % and 2 wt %, respectively. This effect could be related to the elongated shape of the nanoparticles and the presence of two characteristic NPs sizes - 15 and 150 nm. Moreover, the birefringence increase for the samples with 10 wt % NPs concentration (compared with the non-doped samples) was rather significant - nearly 70%. (paper)

  17. Simulations of a spectral gamma-ray logging tool response to a surface source distribution on the borehole wall

    International Nuclear Information System (INIS)

    Wilson, R.D.; Conaway, J.G.

    1991-01-01

    We have developed Monte Carlo and discrete ordinates simulation models for the large-detector spectral gamma-ray (SGR) logging tool in use at the Nevada Test Site. Application of the simulation models produced spectra for source layers on the borehole wall, either from potassium-bearing mudcakes or from plate-out of radon daughter products. Simulations show that the shape and magnitude of gamma-ray spectra from sources distributed on the borehole wall depend on radial position with in the air-filled borehole as well as on hole diameter. No such dependence is observed for sources uniformly distributed in the formation. In addition, sources on the borehole wall produce anisotropic angular fluxes at the higher scattered energies and at the source energy. These differences in borehole effects and in angular flux are important to the process of correcting SGR logs for the presence of potassium mudcakes; they also suggest a technique for distinguishing between spectral contributions from formation sources and sources on the borehole wall. These results imply the existence of a standoff effect not present for spectra measured in air-filled boreholes from formation sources. 5 refs., 11 figs

  18. Enhancing forest tenure reforms through more responsive regulations

    Directory of Open Access Journals (Sweden)

    Anne M Larson

    2012-01-01

    Full Text Available Forest tenure reforms have offered new opportunities for communities to obtain formal rights to forests and forest benefits, but at the same time a variety of limitations are placed on livelihood options. This article draws on several case studies of reforms in Africa, Asia and Latin America to analyse the regulations accompanying reforms. It identifies three types of regulations, namely rules that limit areas available to local communities; rules that delineate conservation areas and impose related limits on use; and bureaucratic requirements for permits and management plans, which restrict the commercial use and marketing of valuable forest products. It discusses problems with these regulations, and proposes a simple framework for identifying ways to promote regulations that work for forest conservation but are more responsive to the needs of communities and forests.

  19. Stimulation of dendritic cells enhances immune response after photodynamic therapy

    Science.gov (United States)

    Mroz, Pawel; Castano, Ana P.; Hamblin, Michael R.

    2009-02-01

    Photodynamic therapy (PDT) involves the administration of photosensitizers followed by illumination of the primary tumor with red light producing reactive oxygen species that cause vascular shutdown and tumor cell necrosis and apoptosis. Anti-tumor immunity is stimulated after PDT due to the acute inflammatory response, priming of the immune system to recognize tumor-associated antigens (TAA). The induction of specific CD8+ Tlymphocyte cells that recognize major histocompatibility complex class I (MHC-I) restricted epitopes of TAAs is a highly desirable goal in cancer therapy. The PDT killed tumor cells may be phagocytosed by dendritic cells (DC) that then migrate to draining lymph nodes and prime naÃve T-cells that recognize TAA epitopes. This process is however, often sub-optimal, in part due to tumor-induced DC dysfunction. Instead of DC that can become mature and activated and have a potent antigen-presenting and immune stimulating phenotype, immature dendritic cells (iDC) are often found in tumors and are part of an immunosuppressive milieu including regulatory T-cells and immunosuppressive cytokines such as TGF-beta and IL10. We here report on the use of a potent DC activating agent, an oligonucleotide (ODN) that contains a non-methylated CpG motif and acts as an agonist of toll like receptor (TLR) 9. TLR activation is a danger signal to notify the immune system of the presence of invading pathogens. CpG-ODN (but not scrambled non-CpG ODN) increased bone-marrow DC activation after exposure to PDT-killed tumor cells, and significantly increased tumor response to PDT and mouse survival after peri-tumoral administration. CpG may be a valuable immunoadjuvant to PDT especially for tumors that produce DC dysfunction.

  20. Weight cycling enhances adipose tissue inflammatory responses in male mice.

    Directory of Open Access Journals (Sweden)

    Sandra Barbosa-da-Silva

    Full Text Available BACKGROUND: Obesity is associated with low-grade chronic inflammation attributed to dysregulated production, release of cytokines and adipokines and to dysregulated glucose-insulin homeostasis and dyslipidemia. Nutritional interventions such as dieting are often accompanied by repeated bouts of weight loss and regain, a phenomenon known as weight cycling (WC. METHODS: In this work we studied the effects of WC on the feed efficiency, blood lipids, carbohydrate metabolism, adiposity and inflammatory markers in C57BL/6 male mice that WC two or three consecutive times by alternation of a high-fat (HF diet with standard chow (SC. RESULTS: The body mass (BM grew up in each cycle of HF feeding, and decreased after each cycle of SC feeding. The alterations observed in the animals feeding HF diet in the oral glucose tolerance test, in blood lipids, and in serum and adipose tissue expression of adipokines were not recuperated after WC. Moreover, the longer the HF feeding was (two, four and six months, more severe the adiposity was. After three consecutive WC, less marked was the BM reduction during SC feeding, while more severe was the BM increase during HF feeding. CONCLUSION: In conclusion, the results of the present study showed that both the HF diet and WC are relevant to BM evolution and fat pad remodeling in mice, with repercussion in blood lipids, homeostasis of glucose-insulin and adipokine levels. The simple reduction of the BM during a WC is not able to recover the high levels of adipokines in the serum and adipose tissue as well as the pro-inflammatory cytokines enhanced during a cycle of HF diet. These findings are significant because a milieu with altered adipokines in association with WC potentially aggravates the chronic inflammation attributed to dysregulated production and release of adipokines in mice.

  1. In situ spectral response of the Arabian Gulf and Sea of Oman coastal waters to bio-optical properties.

    Science.gov (United States)

    Al Shehhi, Maryam R; Gherboudj, Imen; Ghedira, Hosni

    2017-10-01

    Mapping of Chlorophyll-a (Chl-a) over the coastal waters of the Arabian Gulf and the Sea of Oman using the satellite-based observations, such as MODIS (Moderate Resolution Imaging Spectro-radiometer), has shown inferior performance (Chl-a overestimation) than that of deep waters. Studies in the region have shown that this poor performance is due to three reasons: (i) water turbidity (sediments re-suspension), and the presence of colored dissolved organic matter (CDOM), (ii) bottom reflectance and (iii) incapability of the existing atmospheric correction models to reduce the effect of the aerosols from the water leaving radiance. Therefore, this work focuses on investigating the sensitivity of the in situ spectral signatures of these coastal waters to the algal (chlorophyll: Chl-a), non-algal (sediments and CDOM) and the bottom reflectance properties, in absence of contributions from the atmosphere. Consequently, the collected in situ spectral signatures will improve our understanding of Arabian Gulf and Sea of Oman water properties. For this purpose, comprehensive field measurements were carried out between 2013 and 2016, over Abu-Dhabi (Arabian Gulf) and Fujairah (Sea of Oman) where unique water quality data were collected. Based on the in situ water spectral analysis, the bottom reflectance (water depth<20m) are found to degrade the performance of the conventional ocean color algorithms more than the sediment-laden waters where these waters increase the R rs at the blue and red ranges. The increasing presence of CDOM markedly decreases the R rs in the blue range, which is conflicting with the effect of Chl-a. Given the inadequate performance of the widely used ocean-color algorithms (OC3: ocean color 3, OC2: ocean color 2) in retrieving Chl-a in these very shallow coastal waters, therefore, a new algorithm is proposed here based on a 3-bands ratio approach using [R rs (656) -1 -R rs (506) -1 ]×R rs (661). The selected optimum bands (656nm, 506nm, and 661nm) from

  2. Language experience enhances early cortical pitch-dependent responses

    Science.gov (United States)

    Krishnan, Ananthanarayan; Gandour, Jackson T.; Ananthakrishnan, Saradha; Vijayaraghavan, Venkatakrishnan

    2014-01-01

    Pitch processing at cortical and subcortical stages of processing is shaped by language experience. We recently demonstrated that specific components of the cortical pitch response (CPR) index the more rapidly-changing portions of the high rising Tone 2 of Mandarin Chinese, in addition to marking pitch onset and sound offset. In this study, we examine how language experience (Mandarin vs. English) shapes the processing of different temporal attributes of pitch reflected in the CPR components using stimuli representative of within-category variants of Tone 2. Results showed that the magnitude of CPR components (Na-Pb and Pb-Nb) and the correlation between these two components and pitch acceleration were stronger for the Chinese listeners compared to English listeners for stimuli that fell within the range of Tone 2 citation forms. Discriminant function analysis revealed that the Na-Pb component was more than twice as important as Pb-Nb in grouping listeners by language affiliation. In addition, a stronger stimulus-dependent, rightward asymmetry was observed for the Chinese group at the temporal, but not frontal, electrode sites. This finding may reflect selective recruitment of experience-dependent, pitch-specific mechanisms in right auditory cortex to extract more complex, time-varying pitch patterns. Taken together, these findings suggest that long-term language experience shapes early sensory level processing of pitch in the auditory cortex, and that the sensitivity of the CPR may vary depending on the relative linguistic importance of specific temporal attributes of dynamic pitch. PMID:25506127

  3. Enhanced gamma interferon responses of mouse spleen cells following immunotherapy for tuberculosis relapse.

    Science.gov (United States)

    Gil, Olga; Vilaplana, Cristina; Guirado, Evelyn; Díaz, Jorge; Cáceres, Neus; Singh, Mahavir; Cardona, Pere-Joan

    2008-11-01

    Gamma interferon responses of spleen cells in mice were examined during postchemotherapy relapse of intraperitoneally induced latent tuberculous infection. The mycobacterial extract RUTI, which prevented the relapse, significantly enhanced the immune responses to secreted and structural recombinant mycobacterial antigens, suggesting that RUTI-mediated protection was mediated by activated T cells.

  4. Enhancement of radiation response in human hepatocarcinoma cells by Metformin

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Eun Ho; Kim, Won Woo; Kim, Joon; Jung, Won Gyun [Division of heavy ion clinical research, Korea University, Seoul (Korea, Republic of); Jeong, Jae Hoon; Jeong, Youn Kyoung; Kim, Mi Sook [Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of)

    2012-11-15

    Metformin (1, 1-dimethylbiguanide hydrochloride), the most widely used drug to treat type 2 diabetic patients under benefit good tolerability profile and low cost, has sparked keen interest as potential anticancer agent. Preclinical studies showed that the primary mechanism of action of metformin is through its ability to activate AMP-activated protein kinase (AMPK). Metformin inhibits complex 1 in the mitochondrial electron transport chain, leading to an increase in the AMP-to-ATP ratio, then, phospholylated AMPK increase energy generation or suppress energy consumption and then, inhibits cell growth. However, important caveat in direct action theory of metformin is that millimorlar range, effective dose for inhibition tumor cell growth in vitro, cannot be achieved in patients. This is probably because metformin enter cells through the organic cation transporters OCT1 and OCT2, which is lowly expressed in human cells except liver and adipose cells. dependent pathway rather than through direct effects of the tumor cells. We analyzed combination effect of metformin and radiation focusing to HCC cell lines, which theoretically express high organic cation transporters, producing high centration of metformin in tumor cells. The purpose of this study is to investigate whether metformin had anti-tumor effects when combined with radiation as radiosensitizer in HCC. The results showed that metformin increased radiosensitizing efficacy in HCC cells , as well as in Huh7 xenograft mouse models. Interestingly, metformin effectively sensitizes IR-induced apoptosis in HCC through upregulation of cleaved PARP and caspase3 and increase synergically on DNA damage response with combined treatment.HCC, suggesting potential usefulness of combined therapy of metformin together with radiation for HCC cancer therapy.

  5. Enhancement of radiation response in human hepatocarcinoma cells by Metformin

    International Nuclear Information System (INIS)

    Kim, Eun Ho; Kim, Won Woo; Kim, Joon; Jung, Won Gyun; Jeong, Jae Hoon; Jeong, Youn Kyoung; Kim, Mi Sook

    2012-01-01

    Metformin (1, 1-dimethylbiguanide hydrochloride), the most widely used drug to treat type 2 diabetic patients under benefit good tolerability profile and low cost, has sparked keen interest as potential anticancer agent. Preclinical studies showed that the primary mechanism of action of metformin is through its ability to activate AMP-activated protein kinase (AMPK). Metformin inhibits complex 1 in the mitochondrial electron transport chain, leading to an increase in the AMP-to-ATP ratio, then, phospholylated AMPK increase energy generation or suppress energy consumption and then, inhibits cell growth. However, important caveat in direct action theory of metformin is that millimorlar range, effective dose for inhibition tumor cell growth in vitro, cannot be achieved in patients. This is probably because metformin enter cells through the organic cation transporters OCT1 and OCT2, which is lowly expressed in human cells except liver and adipose cells. dependent pathway rather than through direct effects of the tumor cells. We analyzed combination effect of metformin and radiation focusing to HCC cell lines, which theoretically express high organic cation transporters, producing high centration of metformin in tumor cells. The purpose of this study is to investigate whether metformin had anti-tumor effects when combined with radiation as radiosensitizer in HCC. The results showed that metformin increased radiosensitizing efficacy in HCC cells , as well as in Huh7 xenograft mouse models. Interestingly, metformin effectively sensitizes IR-induced apoptosis in HCC through upregulation of cleaved PARP and caspase3 and increase synergically on DNA damage response with combined treatment.HCC, suggesting potential usefulness of combined therapy of metformin together with radiation for HCC cancer therapy

  6. Diagnosing x-ray power and energy of tungsten wire array z-pinch with a flat spectral response x-ray diode

    International Nuclear Information System (INIS)

    Wang, Kun-lun; Ren, Xiao-dong; Huang, Xian-bin; Zhang, Si-qun; Zhou, Shao-tong; Dan, Jia-kun; Li, Jing; Xu, Qiang; Ouyang, Kai; Cai, Hong-chun; Wei, Bing; Ji, Ce; Feng, Shu-ping; Wang, Meng; Xie, Wei-ping; Deng, Jian-jun

    2015-01-01

    Fast z-pinch is a very efficient way of converting electromagnetic energy to radiation. With an 8-10 MA current on primary test stand facility, about 1 MJ electromagnetic energy is delivered to vacuum chamber, which heats z-pinch plasma to radiate soft x-ray. To develop a pulsed high power x-ray source, we studied the applicability of diagnosing x-ray power from tungsten wire array z-pinch with a flat spectral response x-ray diode (FSR-XRD). The detector was originally developed to diagnose radiation of a hohlraum in SG-III prototype laser facility. It utilized a gold cathode XRD and a specially configured compound gold filter to yield a nearly flat spectral response in photon energy range of 0.1-4 keV. In practice, it was critical to avoid surface contamination of gold cathode. It is illustrated that an exposure of an XRD to multiple shots caused a significant change of response. Thus, in diagnosing x-ray power and energy, we used each XRD in only one shot after calibration. In a shot serial, output of FSR-XRD was compared with output of a nickel bolometer. In these shots, the outputs agreed with each other within their uncertainties which were about 12% for FSR-XRD and about 15% for bolometer. Moreover, the ratios between the FSR-XRD and the bolometer among different shots were explored. In 8 shots, the standard deviation of the ratio was 6%. It is comparable to XRD response change of 7%

  7. Discriminative identification of transcriptional responses of promoters and enhancers after stimulus

    KAUST Repository

    Kleftogiannis, Dimitrios A.

    2016-10-17

    Promoters and enhancers regulate the initiation of gene expression and maintenance of expression levels in spatial and temporal manner. Recent findings stemming from the Cap Analysis of Gene Expression (CAGE) demonstrate that promoters and enhancers, based on their expression profiles after stimulus, belong to different transcription response subclasses. One of the most promising biological features that might explain the difference in transcriptional response between subclasses is the local chromatin environment. We introduce a novel computational framework, PEDAL, for distinguishing effectively transcriptional profiles of promoters and enhancers using solely histone modification marks, chromatin accessibility and binding sites of transcription factors and co-activators. A case study on data from MCF-7 cell-line reveals that PEDAL can identify successfully the transcription response subclasses of promoters and enhancers from two different stimulations. Moreover, we report subsets of input markers that discriminate with minimized classification error MCF-7 promoter and enhancer transcription response subclasses. Our work provides a general computational approach for identifying effectively cell-specific and stimulation-specific promoter and enhancer transcriptional profiles, and thus, contributes to improve our understanding of transcriptional activation in human.

  8. Contrast-enhanced spectral mammography as work-up tool in patients recalled from breast cancer screening has low risks and might hold clinical benefits.

    Science.gov (United States)

    Houben, I P L; Van de Voorde, P; Jeukens, C R L P N; Wildberger, J E; Kooreman, L F; Smidt, M L; Lobbes, M B I

    2017-09-01

    Contrast-enhanced spectral mammography (CESM) is a reliable problem solving tool in the work-up of women recalled from breast cancer screening. We evaluated additional findings caused by CESM alone and outweighed them against the disadvantages of this technique. From December 2012 to December 2015, all women recalled from screening who underwent CESM were considered for this study. Radiation exposure and number of adverse contrast reactions were analysed. An experienced breast radiologist reviewed all exams and identified cases with lesions detected by CESM alone and scored their conspicuity. From these cases, data on breast density and final diagnosis were collected. For malignant cases, tumour grade and receptor characteristics were also collected. During this study, 839 women underwent CESM after a screening recall, in which five minor adverse contrast reactions were observed. Median radiation dose per exam was 6.0mGy (0.9-23.4mGy). Seventy CESM-only lesions were detected in 65 patients. Of these 70 lesions, 54.3% proved to be malignant, most commonly invasive ductal carcinomas. The remaining CESM-only lesions were benign, predominantly fibroadenomas. No complications were observed during biopsy of these lesions. Retrospectively, the majority of the lesions were either occult or a 'minimal sign' on low-energy CESM images or the screening mammogram. Using CESM as a work-up tool for women recalled from screening carries low risk for the patient, while additionally detected tumour foci might hold important clinical implications which need to be further studied in large, randomized controlled trials. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Contrast-enhanced spectral mammography in recalls from the Dutch breast cancer screening program: validation of results in a large multireader, multicase study.

    Science.gov (United States)

    Lalji, U C; Houben, I P L; Prevos, R; Gommers, S; van Goethem, M; Vanwetswinkel, S; Pijnappel, R; Steeman, R; Frotscher, C; Mok, W; Nelemans, P; Smidt, M L; Beets-Tan, R G; Wildberger, J E; Lobbes, M B I

    2016-12-01

    Contrast-enhanced spectral mammography (CESM) is a promising problem-solving tool in women referred from a breast cancer screening program. We aimed to study the validity of preliminary results of CESM using a larger panel of radiologists with different levels of CESM experience. All women referred from the Dutch breast cancer screening program were eligible for CESM. 199 consecutive cases were viewed by ten radiologists. Four had extensive CESM experience, three had no CESM experience but were experienced breast radiologists, and three were residents. All readers provided a BI-RADS score for the low-energy CESM images first, after which the score could be adjusted when viewing the entire CESM exam. BI-RADS 1-3 were considered benign and BI-RADS 4-5 malignant. With this cutoff, we calculated sensitivity, specificity and area under the ROC curve. CESM increased diagnostic accuracy in all readers. The performance for all readers using CESM was: sensitivity 96.9 % (+3.9 %), specificity 69.7 % (+33.8 %) and area under the ROC curve 0.833 (+0.188). CESM is superior to conventional mammography, with excellent problem-solving capabilities in women referred from the breast cancer screening program. Previous results were confirmed even in a larger panel of readers with varying CESM experience. • CESM is consistently superior to conventional mammography • CESM increases diagnostic accuracy regardless of a reader's experience • CESM is an excellent problem-solving tool in recalls from screening programs.

  10. Single-session tDCS over the dominant hemisphere affects contralateral spectral EEG power, but does not enhance neurofeedback-guided event-related desynchronization of the non-dominant hemisphere's sensorimotor rhythm.

    Science.gov (United States)

    Mondini, Valeria; Mangia, Anna Lisa; Cappello, Angelo

    2018-01-01

    Transcranial direct current stimulation (tDCS) and neurofeedback-guided motor imagery (MI) have attracted considerable interest in neurorehabilitation, given their ability to influence neuroplasticity. As tDCS has been shown to modulate event-related desynchronization (ERD), the neural signature of motor imagery detected for neurofeedback, a combination of the techniques was recently proposed. One limitation of this approach is that the area targeted for stimulation is the same from which the signal for neurofeedback is acquired. As tDCS may interfere with proximal electroencephalographic (EEG) electrodes, in this study our aim was to test whether contralateral tDCS could have interhemispheric effects on the spectral power of the unstimulated hemisphere, possibly mediated by transcallosal connection, and whether such effects could be used to enhance ERD magnitudes. A contralateral stimulation approach would indeed facilitate co-registration, as the stimulation electrode would be far from the recording sites. Twenty right-handed healthy volunteers (aged 21 to 32) participated in the study: ten assigned to cathodal, ten to anodal versus sham stimulation. We applied stimulation over the dominant (left) hemisphere, and assessed ERD and spectral power over the non-dominant (right) hemisphere. The effect of tDCS was evaluated over time. Spectral power was assessed in theta, alpha and beta bands, under both rest and MI conditions, while ERD was evaluated in alpha and beta bands. Two main findings emerged: (1) contralateral alpha-ERD was reduced after anodal (p = 0.0147), but not enhanced after cathodal tDCS; (2) both stimulations had remote effects on the spectral power of the contralateral hemisphere, particularly in theta and alpha (significant differences in the topographical t-value maps). The absence of contralateral cathodal ERD enhancement suggests that the protocol is not applicable in the context of MI training. Nevertheless, ERD results of anodal and spectral

  11. Spectral imaging based in vivo model system for characterization of tumor microvessel response to vascular targeting agents

    Science.gov (United States)

    Wankhede, Mamta

    Functional vasculature is vital for tumor growth, proliferation, and metastasis. Many tumor-specific vascular targeting agents (VTAs) aim to destroy this essential tumor vasculature to induce indirect tumor cell death via oxygen and nutrition deprivation. The tumor angiogenesis-inhibiting anti-angiogenics (AIs) and the established tumor vessel targeting vascular disrupting agents (VDAs) are the two major players in the vascular targeting field. Combination of VTAs with conventional therapies or with each other, have been shown to have additive or supra-additive effects on tumor control and treatment. Pathophysiological changes post-VTA treatment in terms of structural and vessel function changes are important parameters to characterize the treatment efficacy. Despite the abundance of information regarding these parameters acquired using various techniques, there remains a need for a quantitative, real-time, and direct observation of these phenomenon in live animals. Through this research we aspired to develop a spectral imaging based mouse tumor system for real-time in vivo microvessel structure and functional measurements for VTA characterization. A model tumor system for window chamber studies was identified, and then combinatorial effects of VDA and AI were characterized in model tumor system. (Full text of this dissertation may be available via the University of Florida Libraries web site. Please check http://www.uflib.ufl.edu/etd.html)

  12. 4T1 Murine Mammary Carcinoma Cells Enhance Macrophage-Mediated Innate Inflammatory Responses.

    Directory of Open Access Journals (Sweden)

    Laurence Madera

    Full Text Available Tumor progression and the immune response are intricately linked. While it is known that cancers alter macrophage inflammatory responses to promote tumor progression, little is known regarding how cancers affect macrophage-dependent innate host defense. In this study, murine bone-marrow-derived macrophages (BMDM were exposed to murine carcinoma-conditioned media prior to assessment of the macrophage inflammatory response. BMDMs exposed to 4T1 mammary carcinoma-conditioned medium demonstrated enhanced production of pro-inflammatory cytokines tumor necrosis factor α, interleukin-6, and CCL2 in response to lipopolysaccharide (LPS while production of interleukin-10 remained unchanged. The increased LPS-induced production of pro-inflammatory cytokines was transient and correlated with enhanced cytokine production in response to other Toll-like receptor agonists, including peptidoglycan and flagellin. In addition, 4T1-conditioned BMDMs exhibited strengthened LPS-induced nitric oxide production and enhanced phagocytosis of Escherichia coli. 4T1-mediated augmentation of macrophage responses to LPS was partially dependent on the NFκB pathway, macrophage-colony stimulating factor, and actin polymerization, as well as the presence of 4T1-secreted extracellular vesicles. Furthermore, peritoneal macrophages obtained from 4T1 tumor-bearing mice displayed enhanced pro-inflammatory cytokine production in response to LPS. These results suggest that uptake of 4T1-secreted factors and actin-mediated ingestion of 4T1-secreted exosomes by macrophages cause a transient enhancement of innate inflammatory responses. Mammary carcinoma-mediated regulation of innate immunity may have significant implications for our understanding of host defense and cancer progression.

  13. Geosynchronous magnetic field responses to fast solar wind dynamic pressure enhancements: MHD field model

    Directory of Open Access Journals (Sweden)

    T. R. Sun

    2012-08-01

    Full Text Available We performed global MHD simulations of the geosynchronous magnetic field in response to fast solar wind dynamic pressure (Pd enhancements. Taking three Pd enhancement events in 2000 as examples, we found that the main features of the total field B and the dominant component Bz can be efficiently predicted by the MHD model. The predicted B and Bz varies with local time, with the highest level near noon and a slightly lower level around mid-night. However, it is more challenging to accurately predict the responses of the smaller component at the geosynchronous orbit (i.e., Bx and By. In contrast, the limitations of T01 model in predicting responses to fast Pd enhancements are presented.

  14. Reliability and responsiveness of dynamic contrast-enhanced magnetic resonance imaging in rheumatoid arthritis

    DEFF Research Database (Denmark)

    Axelsen, M.B.; Poggenborg, R.P.; Stoltenberg, M.

    2013-01-01

    intraarticular injection with 80 mg methylprednisolone. Using semi-automated image processing software, DCE-MRI parameters, including the initial rate of enhancement (IRE) and maximal enhancement (ME), were generated for three regions of interest (ROIs): ‘Whole slice’, ‘Quick ROI’, and ‘Precise ROI......Objectives: To investigate the responsiveness to treatment and the reliability of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) in rheumatoid arthritis (RA) knee joints. Methods: DCE-MRI was performed in 12 clinically active RA knee joints before and 1, 7, 30, and 180 days after......’. The smallest detectable difference (SDD), the smallest detectable change (SDC), and intra- and inter-reader intraclass correlation coefficients (ICCs) were used to assess the reliability of DCE-MRI. Responsiveness to treatment was assessed by the standardized response mean (SRM). Results: In all patients...

  15. Transcription factor assisted loading and enhancer dynamics dictate the hepatic fasting response

    Science.gov (United States)

    Goldstein, Ido; Baek, Songjoon; Presman, Diego M.; Paakinaho, Ville; Swinstead, Erin E.; Hager, Gordon L.

    2017-01-01

    Fasting elicits transcriptional programs in hepatocytes leading to glucose and ketone production. This transcriptional program is regulated by many transcription factors (TFs). To understand how this complex network regulates the metabolic response to fasting, we aimed at isolating the enhancers and TFs dictating it. Measuring chromatin accessibility revealed that fasting massively reorganizes liver chromatin, exposing numerous fasting-induced enhancers. By utilizing computational methods in combination with dissecting enhancer features and TF cistromes, we implicated four key TFs regulating the fasting response: glucocorticoid receptor (GR), cAMP responsive element binding protein 1 (CREB1), peroxisome proliferator activated receptor alpha (PPARA), and CCAAT/enhancer binding protein beta (CEBPB). These TFs regulate fuel production by two distinctly operating modules, each controlling a separate metabolic pathway. The gluconeogenic module operates through assisted loading, whereby GR doubles the number of sites occupied by CREB1 as well as enhances CREB1 binding intensity and increases accessibility of CREB1 binding sites. Importantly, this GR-assisted CREB1 binding was enhancer-selective and did not affect all CREB1-bound enhancers. Single-molecule tracking revealed that GR increases the number and DNA residence time of a portion of chromatin-bound CREB1 molecules. These events collectively result in rapid synergistic gene expression and higher hepatic glucose production. Conversely, the ketogenic module operates via a GR-induced TF cascade, whereby PPARA levels are increased following GR activation, facilitating gradual enhancer maturation next to PPARA target genes and delayed ketogenic gene expression. Our findings reveal a complex network of enhancers and TFs that dynamically cooperate to restore homeostasis upon fasting. PMID:28031249

  16. Contrast-enhanced MR imaging monitoring of acute tumor response to chemotherapy

    International Nuclear Information System (INIS)

    Ranney, D.F.; Cohen, J.M.; Antich, P.P.; Endman, W.A.; Kulkarni, P.; Weinreb, J.C.; Giovanella, B.

    1987-01-01

    Treatment responses of human malignant melanomas were monitored at millimeter resolution in athymic mice by injecting a new polymeric contrast agent, Gd-DTPA-dextran (0.1 mmol Gd/kg, intravenously). Proton MR imaging (0.35 T, spin-echo, repetition time = 0.5 second, echo time = 50 msec) was performed 30 hours after administering diphtheria toxin. Pre-contrast medium images revealed only homogeneous intermediate-intensity tumor masses. Post-contrast medium images of untreated (viable) tumors demonstrated 32% enhancement throughout the entire mass. Post-contrast medium images of toxin-treated tumors revealed marked enhancement (65%) of the histologically viable outer rims, lesser enhancement (38%) of heavily damaged subregions, and no enhancement of dead tumor. These acute, contrast medium-enhanced MR images accurately identified tumor subregions that survived for longer than one week

  17. Radiofrequency ablation of liver cancer: early evaluation of therapeutic response with contrast-enhanced ultrasonography

    International Nuclear Information System (INIS)

    Choi, Dong Gil; Lim, Hyo K.; Lee, Won Jae; Kim, Seung Hoon; Kim, Min Ju; Kim, Seung Kwon; Jang, Kyung Mi; Lee, Ji Yeon; Lim, Jae Hoon

    2004-01-01

    The early assessment of the therapeutic response after percutaneous radiofrequency (RF) ablation is important, in order to correctly decide whether further treatment is necessary. The residual unablated tumor is usually depicted on contrast-enhanced multiphase helical computed tomography (CT) as a focal enhancing structure during the arterial and portal venous phases. Contrast-enhanced color Doppler and power Doppler ultrasonography (US) have also been used to detect residual tumors. Contrast-enhanced gray-scale US, using a harmonic technology which has recently been introduced, allows for the detection of residual tumors after ablation, without any of the blooming or motion artifacts usually seen on contrast-enhanced color or power Doppler US. Based on our experience and reports in the literature, we consider that contrast-enhanced gray-scale harmonic US constitutes a reliable alternative to contrast-enhanced multiphase CT for the early evaluation of the therapeutic response to RF ablation for liver cancer. This technique was also useful in targeting any residual unablated tumors encountered during additional ablation

  18. Ratioing methods for in-flight response calibration of space-based spectro-radiometers, operating in the solar spectral region

    Science.gov (United States)

    Lobb, Dan

    2017-11-01

    One of the most significant problems for space-based spectro-radiometer systems, observing Earth from space in the solar spectral band (UV through short-wave IR), is in achievement of the required absolute radiometric accuracy. Classical methods, for example using one or more sun-illuminated diffusers as reflectance standards, do not generally provide methods for monitoring degradation of the in-flight reference after pre-flight characterisation. Ratioing methods have been proposed that provide monitoring of degradation of solar attenuators in flight, thus in principle allowing much higher confidence in absolute response calibration. Two example methods are described. It is shown that systems can be designed for relatively low size and without significant additions to the complexity of flight hardware.

  19. Enhancing Customer Loyalty towards Corporate Social Responsibility of Thai Mobile Service Providers

    OpenAIRE

    Wichai Onlaor; Siriluck Rotchanakitumnuai

    2010-01-01

    The aim of this research is to develop the understanding of corporate social responsibility (CSR) from consumers- perspective toward Thai mobile service providers. Based on the survey from 400 mobile customers, the result shows that four dimensions of CSR of Thai mobile service providers consist of economic, legal, ethical and philanthropic responsibility. These four CSR factors have positive impacts on enhancing customer satisfaction except one item of economic respon...

  20. Comparability of red/near-infrared reflectance and NDVI based on the spectral response function between MODIS and 30 other satellite sensors using rice canopy spectra.

    Science.gov (United States)

    Huang, Weijiao; Huang, Jingfeng; Wang, Xiuzhen; Wang, Fumin; Shi, Jingjing

    2013-11-26

    Long-term monitoring of regional and global environment changes often depends on the combined use of multi-source sensor data. The most widely used vegetation index is the normalized difference vegetation index (NDVI), which is a function of the red and near-infrared (NIR) spectral bands. The reflectance and NDVI data sets derived from different satellite sensor systems will not be directly comparable due to different spectral response functions (SRF), which has been recognized as one of the most important sources of uncertainty in the multi-sensor data analysis. This study quantified the influence of SRFs on the red and NIR reflectances and NDVI derived from 31 Earth observation satellite sensors. For this purpose, spectroradiometric measurements were performed for paddy rice grown under varied nitrogen levels and at different growth stages. The rice canopy reflectances were convoluted with the spectral response functions of various satellite instruments to simulate sensor-specific reflectances in the red and NIR channels. NDVI values were then calculated using the simulated red and NIR reflectances. The results showed that as compared to the Terra MODIS, the mean relative percentage difference (RPD) ranged from -12.67% to 36.30% for the red reflectance, -8.52% to -0.23% for the NIR reflectance, and -9.32% to 3.10% for the NDVI. The mean absolute percentage difference (APD) compared to the Terra MODIS ranged from 1.28% to 36.30% for the red reflectance, 0.84% to 8.71% for the NIR reflectance, and 0.59% to 9.32% for the NDVI. The lowest APD between MODIS and the other 30 satellite sensors was observed for Landsat5 TM for the red reflectance, CBERS02B CCD for the NIR reflectance and Landsat4 TM for the NDVI. In addition, the largest APD between MODIS and the other 30 satellite sensors was observed for IKONOS for the red reflectance, AVHRR1 onboard NOAA8 for the NIR reflectance and IKONOS for the NDVI. The results also indicated that AVHRRs onboard NOAA7-17 showed

  1. After oxidation, zinc nanoparticles lose their ability to enhance responses to odorants.

    Science.gov (United States)

    Hagerty, Samantha; Daniels, Yasmine; Singletary, Melissa; Pustovyy, Oleg; Globa, Ludmila; MacCrehan, William A; Muramoto, Shin; Stan, Gheorghe; Lau, June W; Morrison, Edward E; Sorokulova, Iryna; Vodyanoy, Vitaly

    2016-12-01

    Electrical responses of olfactory sensory neurons to odorants were examined in the presence of zinc nanoparticles of various sizes and degrees of oxidation. The zinc nanoparticles were prepared by the underwater electrical discharge method and analyzed by atomic force microscopy and X-ray photoelectron spectroscopy. Small (1.2 ± 0.3 nm) zinc nanoparticles significantly enhanced electrical responses of olfactory neurons to odorants. After oxidation, however, these small zinc nanoparticles were no longer capable of enhancing olfactory responses. Larger zinc oxide nanoparticles (15 nm and 70 nm) also did not modulate responses to odorants. Neither zinc nor zinc oxide nanoparticles produced olfactory responses when added without odorants. The enhancement of odorant responses by small zinc nanoparticles was explained by the creation of olfactory receptor dimers initiated by small zinc nanoparticles. The results of this work will clarify the mechanisms for the initial events in olfaction, as well as to provide new ways to alleviate anosmia related to the loss of olfactory receptors.

  2. GOES-R Advanced Baseline Imager: spectral response functions and radiometric biases with the NPP Visible Infrared Imaging Radiometer Suite evaluated for desert calibration sites.

    Science.gov (United States)

    Pearlman, Aaron; Pogorzala, David; Cao, Changyong

    2013-11-01

    The Advanced Baseline Imager (ABI), which will be launched in late 2015 on the National Oceanic and Atmospheric Administration's Geostationary Operational Environmental Satellite R-series satellite, will be evaluated in terms of its data quality postlaunch through comparisons with other satellite sensors such as the recently launched Visible Infrared Imaging Radiometer Suite (VIIRS) aboard the Suomi National Polar-orbiting Partnership satellite. The ABI has completed much of its prelaunch characterization and its developers have generated and released its channel spectral response functions (response versus wavelength). Using these responses and constraining a radiative transfer model with ground reflectance, aerosol, and water vapor measurements, we simulate observed top of atmosphere (TOA) reflectances for analogous visible and near infrared channels of the VIIRS and ABI sensors at the Sonoran Desert and White Sands National Monument sites and calculate the radiometric biases and their uncertainties. We also calculate sensor TOA reflectances using aircraft hyperspectral data from the Airborne Visible/Infrared Imaging Spectrometer to validate the uncertainties in several of the ABI and VIIRS channels and discuss the potential for validating the others. Once on-orbit, calibration scientists can use these biases to ensure ABI data quality and consistency to support the numerical weather prediction community and other data users. They can also use the results for ABI or VIIRS anomaly detection and resolution.

  3. Spectral calibration of EBT3 and HD-V2 radiochromic film response at high dose using 20 MeV proton beams

    Science.gov (United States)

    Feng, Yiwei; Tiedje, Henry F.; Gagnon, Katherine; Fedosejevs, Robert

    2018-04-01

    Radiochromic film is used extensively in many medical, industrial, and scientific applications. In particular, the film is used in analysis of proton generation and in high intensity laser-plasma experiments where very high dose levels can be obtained. The present study reports calibration of the dose response of Gafchromic EBT3 and HD-V2 radiochromic films up to high exposure densities. A 2D scanning confocal densitometer system is employed to carry out accurate optical density measurements up to optical density 5 on the exposed films at the peak spectral absorption wavelengths. Various wavelengths from 400 to 740 nm are also scanned to extend the practical dose range of such films by measuring the response at wavelengths removed from the peak response wavelengths. Calibration curves for the optical density versus exposure dose are determined and can be used for quantitative evaluation of measured doses based on the measured optical densities. It was found that blue and UV wavelengths allowed the largest dynamic range though at some trade-off with overall accuracy.

  4. Discriminative identification of transcriptional responses of promoters and enhancers after stimulus

    KAUST Repository

    Kleftogiannis, Dimitrios A.; Kalnis, Panos; Arner, Erik; Bajic, Vladimir B.

    2016-01-01

    factors and co-activators. A case study on data from MCF-7 cell-line reveals that PEDAL can identify successfully the transcription response subclasses of promoters and enhancers from two different stimulations. Moreover, we report subsets of input markers

  5. Responsive copolymers for enhanced petroleum recovery. Quarterly technical progress report, December 21, 1994--March 22, 1995

    Energy Technology Data Exchange (ETDEWEB)

    McCormick, C.; Hester, R.

    1995-05-01

    The purpose of this study is to extend the concept of micellar polymerization to more complex systems, and to explore the responsive nature of hydrophobically modified polyelectrolytes by tailoring the microstructure. The synthesis of hydrophobically modified acrylamide/acrylic acid copolymer is described. These types of polymers are of interest as thickening agents utilized in enhanced oil recovery.

  6. Stakeholder Attitudes Toward and Values Embedded in a Sensor-Enhanced Personal Emergency Response System

    DEFF Research Database (Denmark)

    Dahl, Yngve; Farshchian, Babak; Vilarinho, Thomas

    2016-01-01

    This paper provides an empirical understanding of concerns that the application of a sensor-enhanced medical alert system, or personal emergency response (PER) system, raises from the perspective of care receivers (users) and care providers. Data were gathered in the context of a field trial...

  7. Ad Hoc Transient Communities to Enhance Social Interaction and Spread Tutor Responsibilities

    OpenAIRE

    Sloep, Peter; Kester, Liesbeth; Brouns, Francis; Van Rosmalen, Peter; De Vries, Fred; De Croock, Marcel; Koper, Rob

    2007-01-01

    Sloep, P.B., Kester, L. Brouns, F., Van Rosmalen, P., De Vries, F., De Croock, M., Koper, R. (2007) Ad Hoc Transient Communities to Enhance Social Interaction and Spread Tutor Responsibilities. In V. Uskov (Ed.) The Sixth IASTED International Conference on Web-based Education WBE 2007, March 14-16, Chamonix, France (pp. 549-554). Calgary, Canada: Acta Press.

  8. Ad Hoc Transient Communities to Enhance Social Interaction and Spread Tutor Responsibilities

    NARCIS (Netherlands)

    Sloep, Peter; Kester, Liesbeth; Brouns, Francis; Van Rosmalen, Peter; De Vries, Fred; De Croock, Marcel; Koper, Rob

    2007-01-01

    Sloep, P.B., Kester, L. Brouns, F., Van Rosmalen, P., De Vries, F., De Croock, M., Koper, R. (2007) Ad Hoc Transient Communities to Enhance Social Interaction and Spread Tutor Responsibilities. In V. Uskov (Ed.) The Sixth IASTED International Conference on Web-based Education WBE 2007, March 14-16,

  9. Ad Hoc Transient Communities to Enhance Social Interaction and Spread Tutor Responsibilities

    NARCIS (Netherlands)

    Sloep, Peter; Kester, Liesbeth; Brouns, Francis; Van Rosmalen, Peter; De Vries, Fred; De Croock, Marcel; Koper, Rob

    2007-01-01

    Sloep, P.B., Kester, L., Brouns, F., Van Rosmalen, P., De Vries, F., De Croock, M., Koper, R. (2007). Ad Hoc Transient Communities to Enhance Social Interaction and Spread Tutor Responsibilities. Presentation given at the Sixth IASTED International Conference on Web-based Education, 14-16 March,

  10. Enhancing 'Whole-of-Government' Response to Biological Events in Korea: Able Response 2014.

    Science.gov (United States)

    Tak, Sangwoo; Jareb, Anton; Choi, Suon; Sikes, Marvin; Choi, Yeon Hwa; Boo, Hyeong-Wook

    2018-01-01

    Since 2011, the Republic of Korea (ROK) and United States (U.S.) have been collaborating to conduct inter- and intra-governmental exercises to jointly respond to biological events in Korea. These exercises highlight U.S. interest in increasing its global biosurveillance capability and the ROK's interest in improving cooperation among ministries to respond to crises. With Able Response (AR) exercises, the ROK and U.S. have improved coordination among US and ROK government and defense agencies responding to potential bio-threats and identified additional areas on which to apply refinements in policies and practices. In 2014, the AR exercise employed a Biosurveillance Portal (BSP) to facilitate more effective communication among participating agencies and countries including Australia. In the present paper, we seek to provide a comprehensive assessment of the AR 2014 (AR14) exercise and make recommendations for future improvements. Incorporating a more realistic response in future scenarios by integrating a tactical response episode in the exercise is recommended.

  11. Enhanced visual memory during hypnosis as mediated by hypnotic responsiveness and cognitive strategies.

    Science.gov (United States)

    Crawford, H J; Allen, S N

    1983-12-01

    To investigate the hypothesis that hypnosis has an enhancing effect on imagery processing, as mediated by hypnotic responsiveness and cognitive strategies, four experiments compared performance of low and high, or low, medium, and high, hypnotically responsive subjects in waking and hypnosis conditions on a successive visual memory discrimination task that required detecting differences between successively presented picture pairs in which one member of the pair was slightly altered. Consistently, hypnotically responsive individuals showed enhanced performance during hypnosis, whereas nonresponsive ones did not. Hypnotic responsiveness correlated .52 (p less than .001) with enhanced performance during hypnosis, but it was uncorrelated with waking performance (Experiment 3). Reaction time was not affected by hypnosis, although high hypnotizables were faster than lows in their responses (Experiments 1 and 2). Subjects reported enhanced imagery vividness on the self-report Vividness of Visual Imagery Questionnaire during hypnosis. The differential effect between lows and highs was in the anticipated direction but not significant (Experiments 1 and 2). As anticipated, hypnosis had no significant effect on a discrimination task that required determining whether there were differences between pairs of simultaneously presented pictures. Two cognitive strategies that appeared to mediate visual memory performance were reported: (a) detail strategy, which involved the memorization and rehearsal of individual details for memory, and (b) holistic strategy, which involved looking at and remembering the whole picture with accompanying imagery. Both lows and highs reported similar predominantly detail-oriented strategies during waking; only highs shifted to a significantly more holistic strategy during hypnosis. These findings suggest that high hypnotizables have a greater capacity for cognitive flexibility (Batting, 1979) than do lows. Results are discussed in terms of several

  12. A study on the multi-dimensional spectral analysis for response of a piping model with two-seismic inputs

    International Nuclear Information System (INIS)

    Suzuki, K.; Sato, H.

    1975-01-01

    The power and the cross power spectrum analysis by which the vibration characteristic of structures, such as natural frequency, mode of vibration and damping ratio, can be identified would be effective for the confirmation of the characteristics after the construction is completed by using the response for small earthquakes or the micro-tremor under the operating condition. This method of analysis previously utilized only from the view point of systems with single input so far, is extensively applied for the analysis of a medium scale model of a piping system subjected to two seismic inputs. The piping system attached to a three storied concrete structure model which is constructed on a shaking table was excited due to earthquake motions. The inputs to the piping system were recorded at the second floor and the ceiling of the third floor where the system was attached to. The output, the response of the piping system, was instrumented at a middle point on the system. As a result, the multi-dimensional power spectrum analysis is effective for a more reliable identification of the vibration characteristics of the multi-input structure system

  13. Resisting distraction and response inhibition trigger similar enhancements of future performance.

    Science.gov (United States)

    Bissett, Patrick G; Grant, Lauren D; Weissman, Daniel H

    2017-10-01

    Resisting distraction and response inhibition are crucial aspects of cognitive control. Interestingly, each of these abilities transiently improves just after it is utilized. Competing views differ, however, as to whether utilizing either of these abilities (e.g., resisting distraction) enhances future performance involving the other ability (e.g., response inhibition). To distinguish between these views, we combined a Stroop-like task that requires resisting distraction with a restraint variant of the stop-signal task that requires response inhibition. We observed similar sequential-trial effects (i.e., performance enhancements) following trials in which participants (a) resisted distraction (i.e., incongruent go trials) and (b) inhibited a response (i.e., congruent stop trials). First, the congruency effect in go trials, which indexes overall distractibility, was smaller after both incongruent go trials and congruent stop trials than it was after congruent go trials. Second, stop failures were less frequent after both incongruent go trials and congruent stop trials than after congruent go trials. A control experiment ruled out the possibility that perceptual conflict or surprise engendered by occasional stop signals triggers sequential-trial effects independent of stopping. Thus, our findings support a novel, integrated view in which resisting distraction and response inhibition trigger similar sequential enhancements of future performance. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Efficiency enhancement calculations of state-of-the-art solar cells by luminescent layers with spectral shifting, quantum cutting, and quantum tripling function

    NARCIS (Netherlands)

    Ten Kate, O.M.; De Jong, M.; Hintzen, H.T.; Van der Kolk, E.

    2013-01-01

    Solar cells of which the efficiency is not limited by the Shockley-Queisser limit can be obtained by integrating a luminescent spectral conversion layer into the cell structure. We have calculated the maximum efficiency of state-of-the-art c-Si, pc-Si, a-Si, CdTe, GaAs, CIS, CIGS, CGS, GaSb, and Ge

  15. Photoreceptor spectral sensitivity of the compound eyes of black soldier fly (Hermetia illucens) informing the design of LED-based illumination to enhance indoor reproduction

    NARCIS (Netherlands)

    Oonincx, D.G.A.B.; Volk, N.; Diehl, J.J.E.; Loon, van J.J.A.; Belušič, G.

    2016-01-01

    Mating in the black soldier fly (BSF) is a visually mediated behaviour that under natural conditions occurs in full sunlight. Artificial light conditions promoting mating by BSF were designed based on the spectral characteristics of the compound eye retina. Electrophysiological measurements

  16. Recent Visual Experience Shapes Visual Processing in Rats through Stimulus-Specific Adaptation and Response Enhancement.

    Science.gov (United States)

    Vinken, Kasper; Vogels, Rufin; Op de Beeck, Hans

    2017-03-20

    From an ecological point of view, it is generally suggested that the main goal of vision in rats and mice is navigation and (aerial) predator evasion [1-3]. The latter requires fast and accurate detection of a change in the visual environment. An outstanding question is whether there are mechanisms in the rodent visual system that would support and facilitate visual change detection. An experimental protocol frequently used to investigate change detection in humans is the oddball paradigm, in which a rare, unexpected stimulus is presented in a train of stimulus repetitions [4]. A popular "predictive coding" theory of cortical responses states that neural responses should decrease for expected sensory input and increase for unexpected input [5, 6]. Despite evidence for response suppression and enhancement in noninvasive scalp recordings in humans with this paradigm [7, 8], it has proven challenging to observe both phenomena in invasive action potential recordings in other animals [9-11]. During a visual oddball experiment, we recorded multi-unit spiking activity in rat primary visual cortex (V1) and latero-intermediate area (LI), which is a higher area of the rodent ventral visual stream. In rat V1, there was only evidence for response suppression related to stimulus-specific adaptation, and not for response enhancement. However, higher up in area LI, spiking activity showed clear surprise-based response enhancement in addition to stimulus-specific adaptation. These results show that neural responses along the rat ventral visual stream become increasingly sensitive to changes in the visual environment, suggesting a system specialized in the detection of unexpected events. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Temperature sensitivity of soil respiration rates enhanced by microbial community response.

    Science.gov (United States)

    Karhu, Kristiina; Auffret, Marc D; Dungait, Jennifer A J; Hopkins, David W; Prosser, James I; Singh, Brajesh K; Subke, Jens-Arne; Wookey, Philip A; Agren, Göran I; Sebastià, Maria-Teresa; Gouriveau, Fabrice; Bergkvist, Göran; Meir, Patrick; Nottingham, Andrew T; Salinas, Norma; Hartley, Iain P

    2014-09-04

    Soils store about four times as much carbon as plant biomass, and soil microbial respiration releases about 60 petagrams of carbon per year to the atmosphere as carbon dioxide. Short-term experiments have shown that soil microbial respiration increases exponentially with temperature. This information has been incorporated into soil carbon and Earth-system models, which suggest that warming-induced increases in carbon dioxide release from soils represent an important positive feedback loop that could influence twenty-first-century climate change. The magnitude of this feedback remains uncertain, however, not least because the response of soil microbial communities to changing temperatures has the potential to either decrease or increase warming-induced carbon losses substantially. Here we collect soils from different ecosystems along a climate gradient from the Arctic to the Amazon and investigate how microbial community-level responses control the temperature sensitivity of soil respiration. We find that the microbial community-level response more often enhances than reduces the mid- to long-term (90 days) temperature sensitivity of respiration. Furthermore, the strongest enhancing responses were observed in soils with high carbon-to-nitrogen ratios and in soils from cold climatic regions. After 90 days, microbial community responses increased the temperature sensitivity of respiration in high-latitude soils by a factor of 1.4 compared to the instantaneous temperature response. This suggests that the substantial carbon stores in Arctic and boreal soils could be more vulnerable to climate warming than currently predicted.

  18. Enhanced brainstem and cortical evoked response amplitudes: single-trial covariance analysis.

    Science.gov (United States)

    Galbraith, G C

    2001-06-01

    The purpose of the present study was to develop analytic procedures that improve the definition of sensory evoked response components. Such procedures could benefit all recordings but would especially benefit difficult recordings where many trials are contaminated by muscle and movement artifacts. First, cross-correlation and latency adjustment analyses were applied to the human brainstem frequency-following response and cortical auditory evoked response recorded on the same trials. Lagged cross-correlation functions were computed, for each of 17 subjects, between single-trial data and templates consisting of the sinusoid stimulus waveform for the brainstem response and the subject's own smoothed averaged evoked response P2 component for the cortical response. Trials were considered in the analysis only if the maximum correlation-squared (r2) exceeded .5 (negatively correlated trials were thus included). Identical correlation coefficients may be based on signals with quite different amplitudes, but it is possible to assess amplitude by the nonnormalized covariance function. Next, an algorithm is applied in which each trial with negative covariance is matched to a trial with similar, but positive, covariance and these matched-trial pairs are deleted. When an evoked response signal is present in the data, the majority of trials positively correlate with the template. Thus, a residual of positively correlated trials remains after matched covariance trials are deleted. When these residual trials are averaged, the resulting brainstem and cortical responses show greatly enhanced amplitudes. This result supports the utility of this analysis technique in clarifying and assessing evoked response signals.

  19. Análise discriminante dos solos por meio da resposta espectral no nível terrestre Soil discrimination analysis by spectral response in the ground level

    Directory of Open Access Journals (Sweden)

    Marcos Rafael Nanni

    2004-10-01

    Full Text Available O objetivo deste trabalho foi desenvolver e avaliar um método para discriminação das classes de solos a partir de suas respostas espectrais, utilizando-se um sensor em laboratório. Os dados espectrais foram utilizados no desenvolvimento de modelos estatísticos para discriminar as classes de solos de uma área no sudoeste do Estado de São Paulo. Equações discriminantes foram desenvolvidas para as 18 classes. A resposta espectral foi obtida em amostras da porção superficial e da porção subsuperficial dos solos da área de estudo, num total de 370 amostras. As amostras foram coletadas em 185 ha, com uma tradagem por ha. Os resultados demonstraram que as classes de solos podem ser individualizadas e distinguidas pela análise discriminante. A análise registrou índices de acerto acima de 80% de determinação da classe de solo avaliada. O acerto global foi de 90,71% quando se utilizaram todas as classes para a geração dos modelos, e 93,44% quando se utilizaram as dez classes com maior número de indivíduos. O teste estatístico simulado mostrou-se eficiente na análise discriminante, com taxa média de acerto acima de 91%, com erro global de 8,8%. A análise demonstrou redução na qualidade do modelo quando aplicado para um subconjunto de 20% das amostras, com erro global de 33,9%. O método auxilia na discriminação de classes de solos pela sua reflectância, devido às interações físicas com a energia eletromagnética.The objective of this study was to develop and test a discrimination method for soil classes by their spectral response (SR, using a laboratory sensor. Spectral data were used to develop statistical model for discriminating soil classes in an area at the southwest of São Paulo State, Brazil. Discriminant equations were developed for 18 soil classes. The spectral data were obtained in superficial and subsuperficial soil samples in the study area, with a total of 370 samples. The samples were collected in 185 ha

  20. Enhancing the Responsivity of Uncooled Infrared Detectors Using Plasmonics for High-Performance Infrared Spectroscopy

    Directory of Open Access Journals (Sweden)

    Amr Shebl Ahmed

    2017-04-01

    Full Text Available A lead zirconate titanate (PZT;Pb(Zr0.52Ti0.48O3 layer embedded infrared (IR detector decorated with wavelength-selective plasmonic crystals has been investigated for high-performance non-dispersive infrared (NDIR spectroscopy. A plasmonic IR detector with an enhanced IR absorption band has been designed based on numerical simulations, fabricated by conventional microfabrication techniques, and characterized with a broadly tunable quantum cascade laser. The enhanced responsivity of the plasmonic IR detector at specific wavelength band has improved the performance of NDIR spectroscopy and pushed the limit of detection (LOD by an order of magnitude. In this paper, a 13-fold enhancement in the LOD of a methane gas sensing using NDIR spectroscopy is demonstrated with the plasmonic IR detector.

  1. Spectral methods. Fundamentals in single domains

    International Nuclear Information System (INIS)

    Canuto, C.

    2006-01-01

    Since the publication of ''Spectral Methods in Fluid Dynamics'' 1988, spectral methods have become firmly established as a mainstream tool for scientific and engineering computation. The authors of that book have incorporated into this new edition the many improvements in the algorithms and the theory of spectral methods that have been made since then. This latest book retains the tight integration between the theoretical and practical aspects of spectral methods, and the chapters are enhanced with material on the Galerkin with numerical integration version of spectral methods. The discussion of direct and iterative solution methods is also greatly expanded. (orig.)

  2. γ-Oryzanol-Rich Black Rice Bran Extract Enhances the Innate Immune Response.

    Science.gov (United States)

    Shin, Soon Young; Kim, Heon-Woong; Jang, Hwan-Hee; Hwang, Yu-Jin; Choe, Jeong-Sook; Lim, Yoongho; Kim, Jung-Bong; Lee, Young Han

    2017-09-01

    The innate immune response is an important host primary defense system against pathogens. γ-Oryzanol is one of the nutritionally important phytoceutical components in rice bran oil. The goal of this study was to investigate the effect of γ-oryzanol-rich extract from black rice bran (γORE) on the activation of the innate immune system. In this study, we show that γORE increased the expression of CD14 and Toll-like receptor 4 and enhanced the phagocytic activity of RAW264.7 macrophages. Furthermore, γORE and its active ingredient γ-oryzanol promoted the secretion of innate cytokines, interleukin-8, and CCL2, which facilitate phagocytosis by RAW264.7 cells. These findings suggest that γ-oryzanol in the γORE enhances innate immune responses.

  3. Nanostructure induced changes in lifetime and enhanced second-harmonic response of organic-plasmonic hybrids

    Energy Technology Data Exchange (ETDEWEB)

    Leißner, Till [NanoSYD, Mads Clausen Institute, University of Southern Denmark, Alsion 2, 6400 Sønderborg (Denmark); Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, 5230 Odense (Denmark); Kostiučenko, Oksana; Rubahn, Horst-Günter; Fiutowski, Jacek, E-mail: fiutowski@mci.sdu.dk [NanoSYD, Mads Clausen Institute, University of Southern Denmark, Alsion 2, 6400 Sønderborg (Denmark); Brewer, Jonathan R. [Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, 5230 Odense (Denmark)

    2015-12-21

    In this letter we show that the optical response of organic nanofibers, grown from functionalized para-quaterphenylene molecules, can be controlled by forming organic-plasmonic hybrid systems. The interaction between nanofibers and supporting regular arrays of nanostructures leads to a strongly enhanced second harmonic response. At the same time, the fluorescence lifetime of the nanofibers is reduced from 0.32 ns for unstructured gold films to 0.22 ns for gold nanosquare arrays, demonstrating efficient organic–plasmonic interaction. To study the origin of these effects, we applied two-photon laser scanning microscopy and fluorescence lifetime imaging microscopy. These findings provide an effective approach for plasmon-enhanced second-harmonic generation at the nanoscale, which is attractive for nanophotonic circuitry.

  4. The Auditory Enhancement Effect is Not Reflected in the 80-Hz Auditory Steady-State Response

    OpenAIRE

    Carcagno, Samuele; Plack, Christopher J.; Portron, Arthur; Semal, Catherine; Demany, Laurent

    2014-01-01

    The perceptual salience of a target tone presented in a multitone background is increased by the presentation of a precursor sound consisting of the multitone background alone. It has been proposed that this “enhancement” phenomenon results from an effective amplification of the neural response to the target tone. In this study, we tested this hypothesis in humans, by comparing the auditory steady-state response (ASSR) to a target tone that was enhanced by a precursor sound with the ASSR to a...

  5. Dietary exposure to benzoxazinoids enhances bacteria-induced monokine responses by peripheral blood mononuclear cells

    DEFF Research Database (Denmark)

    Damgaard, Dres; Jensen, Bettina Margrethe; Palarasah, Yaseelan

    2015-01-01

    -out, the groups switched diets. Peripheral blood mononuclear cells (PBMCs) were stimulated with Porphyromonas gingivalis, Escherichia coli lipopolysaccharide (LPS), or tetanus toxoid (TT). PBMCs from a healthy donor received the same stimuli in presence of serum from each participant receiving BXs. The production...... of monokines, T-cell cytokines and T-helper cell proliferation were assessed. A 3-wk diet with high BX content enhanced IL-1β responses against LPS and P. gingivalis, as well as TNF-α response against P. gingivalis, after 24 h of stimulation. Moreover, IL-6 was found to be increased after 7 days of stimulation...

  6. Development of visible-light responsive and mechanically enhanced "smart" UCST interpenetrating network hydrogels.

    Science.gov (United States)

    Xu, Yifei; Ghag, Onkar; Reimann, Morgan; Sitterle, Philip; Chatterjee, Prithwish; Nofen, Elizabeth; Yu, Hongyu; Jiang, Hanqing; Dai, Lenore L

    2017-12-20

    An interpenetrating polymer network (IPN), chlorophyllin-incorporated environmentally responsive hydrogel was synthesized and exhibited the following features: enhanced mechanical properties, upper critical solution temperature (UCST) swelling behavior, and promising visible-light responsiveness. Poor mechanical properties are known challenges for hydrogel-based materials. By forming an interpenetrating network between polyacrylamide (PAAm) and poly(acrylic acid) (PAAc) polymer networks, the mechanical properties of the synthesized IPN hydrogels were significantly improved compared to hydrogels made of a single network of each polymer. The formation of the interpenetrating network was confirmed by Fourier Transform Infrared Spectroscopy (FTIR), the analysis of glass transition temperature, and a unique UCST responsive swelling behavior, which is in contrast to the more prevalent lower critical solution temperature (LCST) behaviour of environmentally responsive hydrogels. The visible-light responsiveness of the synthesized hydrogel also demonstrated a positive swelling behavior, and the effect of incorporating chlorophyllin as the chromophore unit was observed to reduce the average pore size and further enhance the mechanical properties of the hydrogel. This interpenetrating network system shows potential to serve as a new route in developing "smart" hydrogels using visible-light as a simple, inexpensive, and remotely controllable stimulus.

  7. Sensory input from the osphradium modulates the response to memory-enhancing stressors in Lymnaea stagnalis.

    Science.gov (United States)

    Karnik, Vikram; Braun, Marvin; Dalesman, Sarah; Lukowiak, Ken

    2012-02-01

    In the freshwater environment species often rely on chemosensory information to modulate behavior. The pond snail, Lymnaea stagnalis, is a model species used to characterize the causal mechanisms of long-term memory (LTM) formation. Chemical stressors including crayfish kairomones and KCl enhance LTM formation (≥24 h) in Lymnaea; however, how these stressors are sensed and the mechanism by which they affect the electrophysiological properties of neurons necessary for memory formation are poorly understood. Here, we assessed whether the osphradium, a primary chemosensory organ in Lymnaea, modulates LTM enhancement. To test this we severed the osphradial nerve proximal to the osphradium, using sham-operated animals as controls, and assessed the behavioral and electrophysiological response to crayfish kairomones and KCl. We operantly conditioned aerial respiratory behavior in intact, sham and osphradially cut animals, and tested for enhanced memory formation after exposure to the chemical stressors. Sham-operated animals displayed the same memory enhancement as intact animals but snails with a severed osphradial nerve did not show LTM enhancement. Extracellular recordings made from the osphradial nerve demonstrate that these stressors evoked afferent sensory activity. Intracellular recordings from right pedal dorsal 1 (RPeD1), a neuron necessary for LTM formation, demonstrate that its electrophysiological activity is altered by input from the osphradium following exposure to crayfish kairomones or KCl in sham and intact animals but no response is seen in RPeD1 in osphradially cut animals. Therefore, sensory input from the osphradium is necessary for LTM enhancement following exposure to these chemical stressors.

  8. Evaluation of the Physiological Challenges in Extreme Environments: Implications for Enhanced Training, Operational Performance and Sex-Specific Responses

    Science.gov (United States)

    2017-10-01

    Operational Performance and Sex -Specific Responses PRINCIPAL INVESTIGATOR: Brent C. Ruby CONTRACTING ORGANIZATION: The University of Montana Missoula...Implications for Enhanced Training, Operational Performance and Sex -Specific Responses 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT...Evaluation of the physiological challenges in extreme environments: Implications for enhanced training, operational performance and sex -specific

  9. Subconscious detection of threat as reflected by an enhanced response bias.

    Science.gov (United States)

    Windmann, S; Krüger, T

    1998-12-01

    Neurobiological and cognitive models of unconscious information processing suggest that subconscious threat detection can lead to cognitive misinterpretations and false alarms, while conscious processing is assumed to be perceptually and conceptually accurate and unambiguous. Furthermore, clinical theories suggest that pathological anxiety results from a crude preattentive warning system predominating over more sophisticated and controlled modes of processing. We investigated the hypothesis that subconscious detection of threat in a cognitive task is reflected by enhanced "false signal" detection rather than by selectively enhanced discrimination of threat items in 30 patients with panic disorder and 30 healthy controls. We presented a tachistoscopic word-nonword discrimination task and a subsequent recognition task and analyzed the data by means of process-dissociation procedures. In line with our expectations, subjects of both groups showed more false signal detection to threat than to neutral stimuli as indicated by an enhanced response bias, whereas indices of discriminative sensitivity did not show this effect. In addition, patients with panic disorder showed a generally enhanced response bias in comparison to healthy controls. They also seemed to have processed the stimuli less elaborately and less differentially. Results are consistent with the assumption that subconscious threat detection can lead to misrepresentations of stimulus significance and that pathological anxiety is characterized by a hyperactive preattentive alarm system that is insufficiently controlled by higher cognitive processes. Copyright 1998 Academic Press.

  10. Antigen delivery by α2-macroglobulin enhances the cytotoxic T lymphocyte response

    Science.gov (United States)

    Bowers, Edith V.; Horvath, Jeffrey J.; Bond, Jennifer E.; Cianciolo, George J.; Pizzo, Salvatore V.

    2009-01-01

    α2M* targets antigens to APCs for rapid internalization, processing, and presentation. When used as an antigen-delivery vehicle, α2M* amplifies MHC class II presentation, as demonstrated by increased antibody titers. Recent evidence, however, suggests that α2M* encapsulation may also enhance antigen-specific CTL immunity. In this study, we demonstrate that α2M*-delivered antigen (OVA) enhances the production of specific in vitro and in vivo CTL responses. Murine splenocytes expressing a transgenic TCR specific for CTL peptide OVA257–264 (SIINFEKL) demonstrated up to 25-fold greater IFN-γ and IL-2 secretion when treated in vitro with α2M*-OVA compared with soluble OVA. The frequency of IFN-γ-producing cells was increased ∼15-fold, as measured by ELISPOT. Expansion of the OVA-specific CD8+ T cell population, as assayed by tetramer binding and [3H]thymidine incorporation, and OVA-specific cell-mediated cytotoxicity, as determined by a flow cytometric assay, were also enhanced significantly by α2M*-OVA. Furthermore, significant CTL responses were observed at antigen doses tenfold lower than those required with OVA alone. Finally, we also observed enhanced humoral and CTL responses by naïve mice following intradermal immunization with α2M*-OVA. These α2M*-OVA-immunized mice demonstrated increased protection against a s.c.-implanted, OVA-expressing tumor, as demonstrated by delayed tumor growth and prolonged animal survival. The observation that α2M*-mediated antigen delivery elicits specific CTL responses suggests the cross-presentation of antigen onto MHC class I. These results support α2M* as an effective antigen-delivery system that may be particularly useful for vaccines based on weakly immunogenic subunits or requiring dose sparing. PMID:19652028

  11. Analysis of bias voltage dependent spectral response in Ga0.51In0.49P/Ga0.99In0.01As/Ge triple junction solar cell

    International Nuclear Information System (INIS)

    Sogabe, Tomah; Ogura, Akio; Okada, Yoshitaka

    2014-01-01

    Spectral response measurement plays great role in characterizing solar cell device because it directly reflects the efficiency by which the device converts the sunlight into an electrical current. Based on the spectral response results, the short circuit current of each subcell can be quantitatively determined. Although spectral response dependence on wavelength, i.e., the well-known external quantum efficiency (EQE), has been widely used in characterizing multijunction solar cell and has been well interpreted, detailed analysis of spectral response dependence on bias voltage (SR −V bias ) has not been reported so far. In this work, we have performed experimental and numerical studies on the SR −V bias for Ga 0.51 In 0.49 P/Ga 0.99 In 0.01 As/Ge triple junction solar cell. Phenomenological description was given to clarify the mechanism of operation matching point variation in SR −V bias measurements. The profile of SR−V bias curve was explained in detail by solving the coupled two-diode current-voltage characteristic transcend formula for each subcell

  12. Analysis of bias voltage dependent spectral response in Ga{sub 0.51}In{sub 0.49}P/Ga{sub 0.99}In{sub 0.01}As/Ge triple junction solar cell

    Energy Technology Data Exchange (ETDEWEB)

    Sogabe, Tomah, E-mail: Sogabe@mbe.rcast.u-tokyo.ac.jp; Ogura, Akio; Okada, Yoshitaka [Research Center for Advanced Science and Technology (RCAST), The University of Tokyo 4-6-1 Komaba, Meguro-ku, Tokyo 153-8504 (Japan)

    2014-02-21

    Spectral response measurement plays great role in characterizing solar cell device because it directly reflects the efficiency by which the device converts the sunlight into an electrical current. Based on the spectral response results, the short circuit current of each subcell can be quantitatively determined. Although spectral response dependence on wavelength, i.e., the well-known external quantum efficiency (EQE), has been widely used in characterizing multijunction solar cell and has been well interpreted, detailed analysis of spectral response dependence on bias voltage (SR −V{sub bias}) has not been reported so far. In this work, we have performed experimental and numerical studies on the SR −V{sub bias} for Ga{sub 0.51}In{sub 0.49}P/Ga{sub 0.99}In{sub 0.01}As/Ge triple junction solar cell. Phenomenological description was given to clarify the mechanism of operation matching point variation in SR −V{sub bias} measurements. The profile of SR−V{sub bias} curve was explained in detail by solving the coupled two-diode current-voltage characteristic transcend formula for each subcell.

  13. Contrast Dose and Radiation Dose Reduction in Abdominal Enhanced Computerized Tomography Scans with Single-phase Dual-energy Spectral Computerized Tomography Mode for Children with Solid Tumors

    OpenAIRE

    Tong Yu; Jun Gao; Zhi-Min Liu; Qi-Feng Zhang; Yong Liu; Ling Jiang; Yun Peng

    2017-01-01

    Background: Contrast dose and radiation dose reduction in computerized tomography (CT) scan for adult has been explored successfully, but there have been few studies on the application of low-concentration contrast in pediatric abdominal CT examinations. This was a feasibility study on the use of dual-energy spectral imaging and adaptive statistical iterative reconstruction (ASiR) for the reduction of radiation dose and iodine contrast dose in pediatric abdominal CT patients with solid tumors...

  14. Visible light communications using predistortion signal to enhance the response of passive optical receiver

    Science.gov (United States)

    Liu, Yang; Chen, Hung-Yu; Liang, Kevin; Wei, Liang-Yu; Chow, Chi-Wai; Yeh, Chien-Hung

    2016-01-01

    Traditional visible light communication (VLC) uses positive-intrinsic-negative photodiode (PD) or avalanche PD as the optical receivers (Rx). We demonstrate using a solar cell as the VLC Rx. The solar cell is flexible and low cost and converts the optical signal into an electrical signal directly without the need of external power supply. In addition to acting as the VLC passive Rx, the converted electrical signal from the solar cell can charge up the battery of the Rx nodes. Hence, the proposed scheme can be a promising candidate for the future Internet of Things network. However, a solar cell acting as a VLC Rx is very challenging, since the response of the solar cell is limited. Here, we propose and demonstrate using predistortion to significantly enhance the solar cell Rx response for the first time up to the authors' knowledge. Experimental results show that the response of the solar cell Rx is significantly enhanced; and the original 2-kHz detection bandwidth of the solar cell can be enhanced by 250 times for receiving 500-kbit/s VLC signal at a transmission distance of 1 m. The operation principle, the generated voltage by the solar cell, and the maximum data rates achieved at different transmission distances are also studied.

  15. Efficiency enhancement of ZnO nanostructure assisted Si solar cell based on fill factor enlargement and UV-blue spectral down-shifting

    International Nuclear Information System (INIS)

    Gholizadeh, A; Reyhani, A; Mortazavi, S Z; Parvin, P

    2017-01-01

    ZnO nanostructures (including nano-plates and nano-rods (NRs)) are grown in various temperatures and Ar/O 2 flow rates using thermal chemical vapor deposition, which affect the structure, nano-plate/NR population, and the quality of ZnO nanostructures. X-ray diffraction (XRD) attests that the peak intensity of the crystallographic plane (1 0 0) is correlated to nano-plate abundance. Moreover, optical properties elucidate that the population of nano-plates in samples strongly affect the band gap, binding energy of the exciton, and UV–visible (UV–vis) absorption and spectral luminescence emissions. In fact, the exciton binding energy reduces from ∼100 to 80 meV when the population of nano-plates increases in samples. Photovoltaic characteristics based on the drop-casting on Si solar cells reveals three dominant factors, namely, the equivalent series resistance, decreasing reflectance, and down-shifting, in order to scale up the absolute efficiency by 3%. As a consequence, the oxygen vacancies in ZnO nanostructures give rise to the down-shifting and increase of free-carriers, leading to a reduction in the equivalent series resistance and an enlargement of fill factor. To obtain a larger I sc , reduction of spectral reflectance is essential; however, the down-shifting process is shown to be dominant by lessening the surface electron-hole recombination rate over the UV–blue spectral range. (paper)

  16. Efficiency enhancement of ZnO nanostructure assisted Si solar cell based on fill factor enlargement and UV-blue spectral down-shifting

    Science.gov (United States)

    Gholizadeh, A.; Reyhani, A.; Parvin, P.; Mortazavi, S. Z.

    2017-05-01

    ZnO nanostructures (including nano-plates and nano-rods (NRs)) are grown in various temperatures and Ar/O2 flow rates using thermal chemical vapor deposition, which affect the structure, nano-plate/NR population, and the quality of ZnO nanostructures. X-ray diffraction (XRD) attests that the peak intensity of the crystallographic plane (1 0 0) is correlated to nano-plate abundance. Moreover, optical properties elucidate that the population of nano-plates in samples strongly affect the band gap, binding energy of the exciton, and UV-visible (UV-vis) absorption and spectral luminescence emissions. In fact, the exciton binding energy reduces from ~100 to 80 meV when the population of nano-plates increases in samples. Photovoltaic characteristics based on the drop-casting on Si solar cells reveals three dominant factors, namely, the equivalent series resistance, decreasing reflectance, and down-shifting, in order to scale up the absolute efficiency by 3%. As a consequence, the oxygen vacancies in ZnO nanostructures give rise to the down-shifting and increase of free-carriers, leading to a reduction in the equivalent series resistance and an enlargement of fill factor. To obtain a larger I sc, reduction of spectral reflectance is essential; however, the down-shifting process is shown to be dominant by lessening the surface electron-hole recombination rate over the UV-blue spectral range.

  17. The effect of irradiation by 173Cs and 60Co on the optical and spectral response properties of lead iodide thin films

    International Nuclear Information System (INIS)

    Jamil, S. S. B.; Ltaif, A. K.; Fadhel, H. M.

    2012-12-01

    This films of solution grown PbI 2 and of pure material of PbI 2 have been deposited onto glass substrate at 100o C by vacuum thermal evaporation technique. Some physical properties of samples without and with gamma radiation are studied. The irradiation process to the samples were made by applied sample to 1 73 'Cs source with activity 0.635 μci and 6 0C o source with activity 0.62 μci without and with different times of irradiation (3,4,5,6, weeks) to obtain the suitable dose. The x-ray diffraction analysis confirmed that PbI 2 films are polycrystalline, having bollixing structure. Transmission spectra, absorption coefficient and band gap energy are studies were also carried out in the wavelength region of 420-900 nm. The band gap of Pb1 2 at room temperature was found to be 2.37-2.78 eV with direct transition nature using the plots were calculated which were machinating with earlier reported value. The spectral photocurrent of PbI 2 layers deposited in different time were also studied, it is found the maximum photocurrent response always is between the wavelength 490-500 nm. (Author)

  18. Assessing the Effects of Suomi NPP VIIRS M15/M16 Detector Radiometric Stability and Relative Spectral Response Variation on Striping

    Directory of Open Access Journals (Sweden)

    Zhuo Wang

    2016-02-01

    Full Text Available Modern satellite radiometers have many detectors with different relative spectral response (RSR. Effect of RSR differences on striping and the root cause of striping in sensor data record (SDR radiance and brightness temperature products have not been well studied. A previous study used MODTRAN radiative transfer model (RTM to analyze striping. In this study, we make efforts to find the possible root causes of striping. Line-by-Line RTM (LBLRTM is used to evaluate the effect of RSR difference on striping and the atmospheric dependency for VIIRS bands M15 and M16. The results show that previous study using MODTRAN is repeatable: the striping is related to the difference between band-averaged and detector-level RSR, and the BT difference has some atmospheric dependency. We also analyzed VIIRS earth view (EV data with several striping index methods. Since the EV data is complex, we further analyze the onboard calibration data. Analysis of Variance (ANOVA test shows that the noise along track direction is the major reason for striping. We also found evidence of correlation between solar diffuser (SD and blackbody (BB for detector 1 in M15. Digital Count Restoration (DCR and detector instability are possibly related to the striping in SD and EV data, but further analysis is needed. These findings can potentially lead to further SDR processing improvements.

  19. UV-vis spectral property of a multi-hydroxyl Schiff-base derivative and its colorimetric response to some special metal ions.

    Science.gov (United States)

    Xing, Lin; Zheng, Xiaoyu; Sun, Wenyu; Yuan, Hua; Hu, Lei; Yan, Zhengquan

    2018-06-05

    A multi-hydroxyl Schiff-base derivative, N-2'-hydroxyl-1'-naphthyl methylene-2-amino phenol (HNMAP), was synthesized and characterized by FTIR, 1 H NMR and UV-vis spectroscopy. It was noted to find there was great effect for solvent and pH on the UV-vis spectroscopy of HNMAP. Especially, some metal ions could make its UV-vis spectra changed regularly with different time-resolved effects. For example, a real-time and multi-wavelength response to Fe 2+ at 520 nm, 466 nm and 447 nm and a quite slow one about 26 min to Fe 3+ at 447 nm and 466 nm, respectively. Under the optimized conditions, the changes in the corresponding absorption intensities at above wavelengths were in proportion to c Fe 2+ or c Fe 3+ during respectively partitioned linear ranges, which realized to quantitatively detect Fe 2+ or Fe 3+ with a large linear range more than two orders of magnitude. A 1:1 complex mode for HNMAP-Fe 2+ and 1:2 for HNMAP-Fe 3+ were proposed from UV-vis spectral titration and Job's plot. HNMAP would be a potential sensor for colorimetric detection of Fe 2+ and Fe 3+ in practice. Copyright © 2018 Elsevier B.V. All rights reserved.

  20. Enhanced electric and magnetic response of a THz sub-wavelength fiber excited by a localized source

    DEFF Research Database (Denmark)

    Atakaramians, Shaghik; Stefani, Alessio; Shardivov, Ilya V.

    2017-01-01

    the magnetic response of the coupled system when excited with an electric dipole oriented along the circumference of the fiber. This result introduces a new platform for achieving enhanced magnetic response, which is the fundamental building block for metamaterial devices. Here we investigate experimentally......Recently we have shown that a nanofiber excited by a localized electric source can have enhanced electric and magnetic response depending of the relative orientation of the source and the fiber [1]. We have demonstrated that the dielectric nanofiber can suppress the electric response and enhance...

  1. The response of macroinvertebrates to artificially enhanced detritus levels in plantation streams

    Science.gov (United States)

    Pretty, J. L.; Dobson, M.

    The leaves and wood from vegetation surrounding headwater streams constitute a major food source for aquatic invertebrates, providing they are retained upon the streambed and not transported downstream. This study investigated the response of aquatic invertebrates to artificially increased detritus retention, in an effort to reproduce the naturally occurring build up of dead organic matter associated with streams in old-growth forest. The background detrital standing stock in streams in Kielder Forest (Northumberland, UK) was low, approximately 32 gm-2. Two streams flowing through dense conifer plantation and one in open broadleaved woodland were manipulated by the addition of logs over a 10 m stream reach. After several months, log addition significantly enhanced detrital standing stocks in both conifer and broadleaved streams. Total invertebrate abundance, taxon richness and the numbers of certain numerically dominant families were significantly higher in experimental than reference reaches in both conifer and broadleaved streams. This response was most marked for detritivores, whilst non-detritivore groups often showed no response to the manipulation. Whilst in the short term the responses to enhanced retention may reflect a redistribution of the local fauna, it is argued that over a longer time-scale, a genuine increase in invertebrate density and diversity could occur. Allowing old-growth forest to develop in planted valley bottoms may be a viable management option for conservation. If established alongside streams, it would ensure continuous input of woody material and the fauna may benefit from the resulting increase in detritus retention.

  2. Application of spectral decomposition of 222Rn activity concentration signal series measured in Niedźwiedzia Cave to identification of mechanisms responsible for different time-period variations

    International Nuclear Information System (INIS)

    Przylibski, Tadeusz Andrzej; Wyłomańska, Agnieszka; Zimroz, Radosław; Fijałkowska-Lichwa, Lidia

    2015-01-01

    phenomena in the lithosphere. - Highlights: • 222 Rn activity concentration monitoring in cave air; • characterisation of signal series decomposition method; • application of spectral decomposition of 222 Rn activity concentration signal series; • identification and characterisation of processes responsible for temporal changes in 222 Rn activity concentration; • application of methods appropriate to time series analysis

  3. Spectral responses in near-infrared of the mixed compounds III-V ternary and quaternary, based on GaSb

    Science.gov (United States)

    Mbow, B.; Rezzoug, N.; Peremarti, C.; Mezerreg, A.; Llinares, C.

    1993-09-01

    From the simulation of the spectral response of the different photodetector devices elaborated in our laboratory (C.E.M.), we determine the influence of geometrical and physical parameters in order to achieve the best photodetector operating at the wavelength 2.55 μm. In this paper we present: Gao{0.6}In{0.4}Sbn/Ga{0.6}In{0.4}Sbp homojunctions matched on GaSbp substrate, Ga{0.75}In{0.25}As{0.23}Sbp/GaSbn ternary heterojunction and GaSbp/Ga{0.74}In{0.26}As{0.23}Sb0.77p/GaSbn quaternary heterojunction. The GaSbp layer with an energy band gap greater than Ga{0.74}In{0.26}As{0.23}Sb0.77p optical gap will act as a window, reducing the effect of surface recombinaison. Results of the simulation are compared to experimental curves to determine the values of photoelectrical parameters (diffusion length, recombination velocity at the surface ...). Les mesures de réponse spectrale dans la gamme [0,4 eV à 2 eV] ont été effectuées sur des homojonctions, Ga{0,6}In{0,4}Sbn/Ga{0,6}In{0,4}Sbp déposées sur un substrat de GaSb et des hétérostructures ternaires Ga{0,75}In{0,25}Sbp/GaSbn et quaternaires GaSbp/Ga{0,74}In{0,26}As{0,23}Sb0,77p/GaSbn. La couche de GaSbp avec un gap plus grand que celui de Ga{0,74}In{0,26}As{0,23}Sb0,77p joue le rôle d'effet fenêtre. En s'appuyant sur les résultats de la simulation et en accordant les spectres expérimentaux aux spectres théoriques, on détermine les valeurs des paramètres photoélectriques (longueurs de diffusion, les vitesses de recombinaison en surface ... ) intervenant dans le rendement quantique.

  4. Hybrid spectral CT reconstruction.

    Directory of Open Access Journals (Sweden)

    Darin P Clark

    Full Text Available Current photon counting x-ray detector (PCD technology faces limitations associated with spectral fidelity and photon starvation. One strategy for addressing these limitations is to supplement PCD data with high-resolution, low-noise data acquired with an energy-integrating detector (EID. In this work, we propose an iterative, hybrid reconstruction technique which combines the spectral properties of PCD data with the resolution and signal-to-noise characteristics of EID data. Our hybrid reconstruction technique is based on an algebraic model of data fidelity which substitutes the EID data into the data fidelity term associated with the PCD reconstruction, resulting in a joint reconstruction problem. Within the split Bregman framework, these data fidelity constraints are minimized subject to additional constraints on spectral rank and on joint intensity-gradient sparsity measured between the reconstructions of the EID and PCD data. Following a derivation of the proposed technique, we apply it to the reconstruction of a digital phantom which contains realistic concentrations of iodine, barium, and calcium encountered in small-animal micro-CT. The results of this experiment suggest reliable separation and detection of iodine at concentrations ≥ 5 mg/ml and barium at concentrations ≥ 10 mg/ml in 2-mm features for EID and PCD data reconstructed with inherent spatial resolutions of 176 μm and 254 μm, respectively (point spread function, FWHM. Furthermore, hybrid reconstruction is demonstrated to enhance spatial resolution within material decomposition results and to improve low-contrast detectability by as much as 2.6 times relative to reconstruction with PCD data only. The parameters of the simulation experiment are based on an in vivo micro-CT experiment conducted in a mouse model of soft-tissue sarcoma. Material decomposition results produced from this in vivo data demonstrate the feasibility of distinguishing two K-edge contrast agents with

  5. Hybrid spectral CT reconstruction

    Science.gov (United States)

    Clark, Darin P.

    2017-01-01

    Current photon counting x-ray detector (PCD) technology faces limitations associated with spectral fidelity and photon starvation. One strategy for addressing these limitations is to supplement PCD data with high-resolution, low-noise data acquired with an energy-integrating detector (EID). In this work, we propose an iterative, hybrid reconstruction technique which combines the spectral properties of PCD data with the resolution and signal-to-noise characteristics of EID data. Our hybrid reconstruction technique is based on an algebraic model of data fidelity which substitutes the EID data into the data fidelity term associated with the PCD reconstruction, resulting in a joint reconstruction problem. Within the split Bregman framework, these data fidelity constraints are minimized subject to additional constraints on spectral rank and on joint intensity-gradient sparsity measured between the reconstructions of the EID and PCD data. Following a derivation of the proposed technique, we apply it to the reconstruction of a digital phantom which contains realistic concentrations of iodine, barium, and calcium encountered in small-animal micro-CT. The results of this experiment suggest reliable separation and detection of iodine at concentrations ≥ 5 mg/ml and barium at concentrations ≥ 10 mg/ml in 2-mm features for EID and PCD data reconstructed with inherent spatial resolutions of 176 μm and 254 μm, respectively (point spread function, FWHM). Furthermore, hybrid reconstruction is demonstrated to enhance spatial resolution within material decomposition results and to improve low-contrast detectability by as much as 2.6 times relative to reconstruction with PCD data only. The parameters of the simulation experiment are based on an in vivo micro-CT experiment conducted in a mouse model of soft-tissue sarcoma. Material decomposition results produced from this in vivo data demonstrate the feasibility of distinguishing two K-edge contrast agents with a spectral

  6. Can quantitative contrast-enhanced ultrasonography predict cervical tumor response to neoadjuvant chemotherapy?

    Energy Technology Data Exchange (ETDEWEB)

    Peng, Chuan; Liu, Long-Zhong; Zheng, Wei [Department of Ultrasound, State Key Laboratory of Oncology in South China, Collaborative Innovation Center of Cancer Medicine, Sun Yat-sen University Cancer Center, 651 Dongfeng Road East, Guangzhou, 510060 (China); Xie, Yan-Jun [Department of Gynecology and Obstetrics, Zhongcun Town hospital, 140 Renmin Road, Zhongcun Town, Panyu District, Guangzhou, 511400 (China); Xiong, Yong-Hong; Li, An-Hua [Department of Ultrasound, State Key Laboratory of Oncology in South China, Collaborative Innovation Center of Cancer Medicine, Sun Yat-sen University Cancer Center, 651 Dongfeng Road East, Guangzhou, 510060 (China); Pei, Xiao-Qing, E-mail: peixq@sysucc.org.cn [Department of Ultrasound, State Key Laboratory of Oncology in South China, Collaborative Innovation Center of Cancer Medicine, Sun Yat-sen University Cancer Center, 651 Dongfeng Road East, Guangzhou, 510060 (China)

    2016-11-15

    Highlights: • We assessed the clinical value of quantitative CEUS for prediction of cervical tumor perfusion response to NACT. • IMAX, RT, and TTP changed significantly after one NACT cycle. • Pre-treatment IMAX positively correlated with the absolute and percentage changes in all cervical tumor IMAX after NACT. • Pre-treatment IMAX may be predictive of NACT perfusion response in cervical tumor. - Abstract: Objective: To evaluate the feasibility of quantitative contrast-enhanced ultrasonography (CEUS) for predicting and assessing cervical tumor response to neoadjuvant chemotherapy (NACT). Methods: Thirty-eight cases with stage IB2 or IIA cervical cancer were studied using CEUS before and after one cycle of NACT. The quantitative CEUS parameters maximum intensity (IMAX), rise time (RT), time to peak (TTP), and mean transit time (MTT) were compared between cervical tumors and myometrium (reference zone) using Sonoliver software. Absolute and relative changes in quantitative CEUS parameters were also compared among complete response, partial response, and non-responsive groups. Correlations between pre-treatment IMAX and changes in quantitative parameters were assessed after one cycle of NACT. Results: There were significant changes in cervical tumor IMAX (P < 0.001), RT (P < 0.05), and TTP (P < 0.05) after one cycle of NACT. According to the Response Evaluation Criteria In Solid Tumors guidelines, the enrollments were divided into complete response, partial response, stable disease and progressive disease groups. There were no significant differences in quantitative CEUS parameters among complete response, partial response, and non-responsive groups (P > 0.05). In the stable disease group (n = 17), cervical tumor IMAX, RT, and TTP decreased significantly after NACT (P < 0.001). The absolute and percentage changes in IMAX were positively correlated with pre-treatment IMAX in all 38 patients (r = 0.576, P < 0.001 and r = 0.429, P < 0.001). Conclusion

  7. The naked truth: the face and body sensitive N170 response is enhanced for nude bodies.

    Directory of Open Access Journals (Sweden)

    Jari K Hietanen

    Full Text Available Recent event-related potential studies have shown that the occipitotemporal N170 component--best known for its sensitivity to faces--is also sensitive to perception of human bodies. Considering that in the timescale of evolution clothing is a relatively new invention that hides the bodily features relevant for sexual selection and arousal, we investigated whether the early N170 brain response would be enhanced to nude over clothed bodies. In two experiments, we measured N170 responses to nude bodies, bodies wearing swimsuits, clothed bodies, faces, and control stimuli (cars. We found that the N170 amplitude was larger to opposite and same-sex nude vs. clothed bodies. Moreover, the N170 amplitude increased linearly as the amount of clothing decreased from full clothing via swimsuits to nude bodies. Strikingly, the N170 response to nude bodies was even greater than that to faces, and the N170 amplitude to bodies was independent of whether the face of the bodies was visible or not. All human stimuli evoked greater N170 responses than did the control stimulus. Autonomic measurements and self-evaluations showed that nude bodies were affectively more arousing compared to the other stimulus categories. We conclude that the early visual processing of human bodies is sensitive to the visibility of the sex-related features of human bodies and that the visual processing of other people's nude bodies is enhanced in the brain. This enhancement is likely to reflect affective arousal elicited by nude bodies. Such facilitated visual processing of other people's nude bodies is possibly beneficial in identifying potential mating partners and competitors, and for triggering sexual behavior.

  8. Background parenchymal enhancement in breast MRI before and after neoadjuvant chemotherapy: correlation with tumour response

    Energy Technology Data Exchange (ETDEWEB)

    Preibsch, H.; Wanner, L.; Bahrs, S.D.; Wietek, B.M.; Nikolaou, K.; Wiesinger, B. [University Hospital Tuebingen, Diagnostic and Interventional Radiology, Tuebingen (Germany); Siegmann-Luz, K.C. [Diagnostic Center for Breast Cancer and Screening Mammography Brandenburg Ost, Koenigs Wusterhausen (Germany); Oberlecher, E.; Hahn, M. [University Hospital Tuebingen, Department of Gynecology and Obstetrics, Tuebingen (Germany); Staebler, A. [University Hospital Tuebingen, Institute of Pathology and Neuropathology, Tuebingen (Germany)

    2016-06-15

    To correlate the decrease in background parenchymal enhancement (BPE) and tumour response measured with MRI in breast cancer patients treated with neoadjuvant chemotherapy (NAC). One hundred and forty-six MRI examinations of 73 patients with 80 biopsy-proven breast cancers who underwent breast MRI before and after NAC were retrospectively analysed. All images were reviewed by two blinded readers, who classified BPE into categories (BEC; 1 = minimal, 2 = mild, 3 = moderate, 4 = marked) before and after NAC. Histopathological and morphological tumour responses were analysed and compared. The distribution of BEC 1/2/3/4 was 25/46/18/11 % before and 78/20/2/0 % after NAC. On average, BPE decreased by 0.87 BEC. Cohen's kappa showed substantial agreement (k = 0.73-0.77) before and moderate agreement (k = 0.43-0.60) after NAC and moderate agreement (k = 0.62-0.60) concerning the change in BEC. Correlating the change in BPE with tumour response, the average decrease in BEC was 1.3 in cases of complete remission, 0.83 in cases with partial response, 0.85 in cases with stable disease and 0.40 in cases with progressive disease. Correlation analysis showed a significant correlation between the decrease in BEC and tumour response (r = -0.24, p = 0.03). BPE decreased by, on average, 0.87 BEC following NAC for breast cancer. The degree of BPE reduction seemed to correlate with tumour response. (orig.)

  9. Withdrawal of repeated morphine enhances histamine-induced scratching responses in mice.

    Science.gov (United States)

    Abe, Kenji; Kobayashi, Kanayo; Yoshino, Saori; Taguchi, Kyoji; Nojima, Hiroshi

    2015-04-01

    An itch is experientially well known that the scratching response of conditions such as atopic dermatitis is enhanced under psychological stress. Morphine is typical narcotic drug that induces a scratching response upon local application as an adverse drug reaction. Although long-term treatment with morphine will cause tolerance and dependence, morphine withdrawal can cause psychologically and physiologically stressful changes in humans. In this study, we evaluated the effects of morphine withdrawal on histamine-induced scratching behavior in mice. Administration of morphine with progressively increasing doses (10-50 mg/kg, i.p.) was performed for 5 consecutive days. At 3, 24, 48, and 72 hr after spontaneous withdrawal from the final morphine dose, histamine was intradermally injected into the rostral part of the back and then the number of bouts of scratching in 60 min was recorded and summed. We found that at 24 hr after morphine withdrawal there was a significant increase in histamine-induced scratching behavior. The spinal c-Fos positive cells were also significantly increased. The relative adrenal weight increased and the relative thymus weight decreased, both significantly. Moreover, the plasma corticosterone levels changed in parallel with the number of scratching bouts. These results suggest that morphine withdrawal induces a stressed state and enhances in histamine-induced scratching behavior. Increased reaction against histamine in the cervical vertebrae will participate in this stress-induced itch enhancement.

  10. C3d enhanced DNA vaccination induced humoral immune response to glycoprotein C of pseudorabies virus

    International Nuclear Information System (INIS)

    Tong Tiezhu; Fan Huiying; Tan Yadi; Xiao Shaobo; Ling Jieyu; Chen Huanchun; Guo Aizhen

    2006-01-01

    Murine C3d were utilized to enhance immunogenicity of pseudorabies virus (PrV) gC DNA vaccination. Three copies of C3d and four copies of CR2-binding domain M28 4 were fused, respectively, to truncated gC gene encoding soluble glycoprotein C (sgC) in pcDNA3.1. BALB/c mice were, respectively, immunized with recombinant plasmids, blank vector, and inactivated vaccine. The antibody ELISA titer for sgC-C3d 3 DNA was 49-fold more than that for sgC DNA, and the neutralizing antibody obtained 8-fold rise. Protection of mice from death after lethal PrV (316 LD 5 ) challenge was augmented from 25% to 100%. Furthermore, C3d fusion increased Th2-biased immune response by inducing IL-4 production. The IL-4 level for sgC-C3d 3 DNA immunization approached that for the inactivated vaccine. Compared to C3d, M28 enhanced sgC DNA immunogenicity to a lesser extent. In conclusion, we demonstrated that murine C3d fusion significantly enhanced gC DNA immunity by directing Th1-biased to a balanced and more effective Th1/Th2 response

  11. Visual Working Memory Enhances the Neural Response to Matching Visual Input.

    Science.gov (United States)

    Gayet, Surya; Guggenmos, Matthias; Christophel, Thomas B; Haynes, John-Dylan; Paffen, Chris L E; Van der Stigchel, Stefan; Sterzer, Philipp

    2017-07-12

    Visual working memory (VWM) is used to maintain visual information available for subsequent goal-directed behavior. The content of VWM has been shown to affect the behavioral response to concurrent visual input, suggesting that visual representations originating from VWM and from sensory input draw upon a shared neural substrate (i.e., a sensory recruitment stance on VWM storage). Here, we hypothesized that visual information maintained in VWM would enhance the neural response to concurrent visual input that matches the content of VWM. To test this hypothesis, we measured fMRI BOLD responses to task-irrelevant stimuli acquired from 15 human participants (three males) performing a concurrent delayed match-to-sample task. In this task, observers were sequentially presented with two shape stimuli and a retro-cue indicating which of the two shapes should be memorized for subsequent recognition. During the retention interval, a task-irrelevant shape (the probe) was briefly presented in the peripheral visual field, which could either match or mismatch the shape category of the memorized stimulus. We show that this probe stimulus elicited a stronger BOLD response, and allowed for increased shape-classification performance, when it matched rather than mismatched the concurrently memorized content, despite identical visual stimulation. Our results demonstrate that VWM enhances the neural response to concurrent visual input in a content-specific way. This finding is consistent with the view that neural populations involved in sensory processing are recruited for VWM storage, and it provides a common explanation for a plethora of behavioral studies in which VWM-matching visual input elicits a stronger behavioral and perceptual response. SIGNIFICANCE STATEMENT Humans heavily rely on visual information to interact with their environment and frequently must memorize such information for later use. Visual working memory allows for maintaining such visual information in the mind

  12. Maternal immunity enhances systemic recall immune responses upon oral immunization of piglets with F4 fimbriae.

    Science.gov (United States)

    Nguyen, Ut V; Melkebeek, Vesna; Devriendt, Bert; Goetstouwers, Tiphanie; Van Poucke, Mario; Peelman, Luc; Goddeeris, Bruno M; Cox, Eric

    2015-06-23

    F4 enterotoxigenic Escherichia coli (ETEC) cause diarrhoea and mortality in piglets leading to severe economic losses. Oral immunization of piglets with F4 fimbriae induces a protective intestinal immune response evidenced by an F4-specific serum and intestinal IgA response. However, successful oral immunization of pigs with F4 fimbriae in the presence of maternal immunity has not been demonstrated yet. In the present study we aimed to evaluate the effect of maternal immunity on the induction of a systemic immune response upon oral immunization of piglets. Whereas F4-specific IgG and IgA could be induced by oral immunization of pigs without maternal antibodies and by intramuscular immunization of pigs with maternal antibodies, no such response was seen in the orally immunized animals with maternal antibodies. Since maternal antibodies can mask an antibody response, we also looked by ELIspot assays for circulating F4-specific antibody secreting cells (ASCs). Enumerating the F4-specific ASCs within the circulating peripheral blood mononuclear cells, and the number of F4-specific IgA ASCs within the circulating IgA(+) B-cells revealed an F4-specific immune response in the orally immunized animals with maternal antibodies. Interestingly, results suggest a more robust IgA booster response by oral immunization of pigs with than without maternal antibodies. These results demonstrate that oral immunization of piglets with F4-specific maternal antibodies is feasible and that these maternal antibodies seem to enhance the secondary systemic immune response. Furthermore, our ELIspot assay on enriched IgA(+) B-cells could be used as a screening procedure to optimize mucosal immunization protocols in pigs with maternal immunity.

  13. Synergy between root hydrotropic response and root biomass in maize (Zea mays L.) enhances drought avoidance.

    Science.gov (United States)

    Eapen, Delfeena; Martínez-Guadarrama, Jesús; Hernández-Bruno, Oralia; Flores, Leonardo; Nieto-Sotelo, Jorge; Cassab, Gladys I

    2017-12-01

    Roots of higher plants change their growth direction in response to moisture, avoiding drought and gaining maximum advantage for development. This response is termed hydrotropism. There have been few studies of root hydrotropism in grasses, particularly in maize. Our goal was to test whether an enhanced hydrotropic response of maize roots correlates with a better adaptation to drought and partial/lateral irrigation in field studies. We developed a laboratory bioassay for testing hydrotropic response in primary roots of 47 maize elite DTMA (Drought Tolerant Maize for Africa) hybrids. After phenotyping these hybrids in the laboratory, selected lines were tested in the field. Three robust and three weak hybrids were evaluated employing three irrigation procedures: normal irrigation, partial lateral irrigation and drought. Hybrids with a robust hydrotropic response showed growth and developmental patterns, under drought and partial lateral irrigation, that differed from weak hydrotropic responders. A correlation between root crown biomass and grain yield in hybrids with robust hydrotropic response was detected. Hybrids with robust hydrotropic response showed earlier female flowering whereas several root system traits, such as projected root area, median width, maximum width, skeleton width, skeleton nodes, average tip diameter, rooting depth skeleton, thinner aboveground crown roots, as well as stem diameter, were considerably higher than in weak hydrotropic responders in the three irrigation procedures utilized. These results demonstrate the benefit of intensive phenotyping of hydrotropism in primary roots since maize plants that display a robust hydrotropic response grew better under drought and partial lateral irrigation, indicating that a selection for robust hydrotropism might be a promising breeding strategy to improve drought avoidance in maize. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Major depression is not associated with blunting of aversive responses; evidence for enhanced anxious anticipation.

    Directory of Open Access Journals (Sweden)

    Christian Grillon

    Full Text Available According to the emotion-context insensitivity (ECI hypothesis, major depressive disorder (MDD is associated with a diminished ability to react emotionally to positive stimuli and with blunting of defensive responses to threat. That defensive responses are blunted in MDD seems inconsistent with the conceptualization and diagnostic nosology of MDD. The present study tested the ECI hypothesis in MDD using a threat of shock paradigm. Twenty-eight patients with MDD (35.5±10.4 years were compared with 28 controls (35.1±7.4 years. Participants were exposed to three conditions: no shock, predictable shock, and unpredictable shock. Startle magnitude was used to assess defensive responses. Inconsistent with the ECI hypothesis, startle potentiation to predictable and unpredictable shock was not reduced in the MDD group. Rather, MDD patients showed elevated startle throughout testing as well as increased contextual anxiety during the placement of the shock electrodes and in the predictable condition. A regression analysis indicated that illness duration and Beck depression inventory scores explained 37% (p<.005 of the variance in patients' startle reactivity. MDD is not associated with emotional blunting but rather enhanced defensive reactivity during anticipation of harm. These results do not support a strong version of the ECI hypothesis. Understanding the nature of stimuli or situations that lead to blunted or enhanced defensive reactivity will provide better insight into dysfunctional emotional experience in MDD.

  15. Major Depression Is Not Associated with Blunting of Aversive Responses; Evidence for Enhanced Anxious Anticipation

    Science.gov (United States)

    Grillon, Christian; Franco-Chaves, Jose A.; Mateus, Camilo F.; Ionescu, Dawn F.; Zarate, Carlos A.

    2013-01-01

    According to the emotion-context insensitivity (ECI) hypothesis, major depressive disorder (MDD) is associated with a diminished ability to react emotionally to positive stimuli and with blunting of defensive responses to threat. That defensive responses are blunted in MDD seems inconsistent with the conceptualization and diagnostic nosology of MDD. The present study tested the ECI hypothesis in MDD using a threat of shock paradigm. Twenty-eight patients with MDD (35.5±10.4 years) were compared with 28 controls (35.1±7.4 years). Participants were exposed to three conditions: no shock, predictable shock, and unpredictable shock. Startle magnitude was used to assess defensive responses. Inconsistent with the ECI hypothesis, startle potentiation to predictable and unpredictable shock was not reduced in the MDD group. Rather, MDD patients showed elevated startle throughout testing as well as increased contextual anxiety during the placement of the shock electrodes and in the predictable condition. A regression analysis indicated that illness duration and Beck depression inventory scores explained 37% (p<.005) of the variance in patients’ startle reactivity. MDD is not associated with emotional blunting but rather enhanced defensive reactivity during anticipation of harm. These results do not support a strong version of the ECI hypothesis. Understanding the nature of stimuli or situations that lead to blunted or enhanced defensive reactivity will provide better insight into dysfunctional emotional experience in MDD. PMID:23951057

  16. Enhancing Organizational Survivability in a Crisis: Perceived Organizational Crisis Responsibility, Stance, and Strategy

    Directory of Open Access Journals (Sweden)

    JiYeon Jeong

    2015-08-01

    Full Text Available For the purpose of enhancing organizational sustainability during a crisis, an organization takes a position in decision-making, how to respond toward its public, and that is supposed to determine which stance or tactic to employ. This study aims to examine whether publics’ perceptions of organizational crisis responsibility affect their expectations that an organization should choose certain stances and strategies toward the public in a crisis. To address these concerns, an experiment was conducted. As the specific public of this research, health journalists were selected, since they affect public perceptions significantly and public opinion can ultimately put pressure on an organization. Results from an analysis of the experimental data with health journalists confirm that they expect a more accommodative stance/strategy when they perceive that the organization is highly responsible for a health-related crisis. Conversely, when the journalists perceive that an organization has a low level of responsibility for a crisis, they expect a more advocative stance/strategy. By taking into account the health journalists’ expectations along with the needs of the organization, public relations practitioners are better able to make optimal decisions regarding their client organizations’ adopted stance and strategy, and finally, enhance organizational sustainability in a crisis.

  17. Cognitive emotion regulation enhances aversive prediction error activity while reducing emotional responses.

    Science.gov (United States)

    Mulej Bratec, Satja; Xie, Xiyao; Schmid, Gabriele; Doll, Anselm; Schilbach, Leonhard; Zimmer, Claus; Wohlschläger, Afra; Riedl, Valentin; Sorg, Christian

    2015-12-01

    Cognitive emotion regulation is a powerful way of modulating emotional responses. However, despite the vital role of emotions in learning, it is unknown whether the effect of cognitive emotion regulation also extends to the modulation of learning. Computational models indicate prediction error activity, typically observed in the striatum and ventral tegmental area, as a critical neural mechanism involved in associative learning. We used model-based fMRI during aversive conditioning with and without cognitive emotion regulation to test the hypothesis that emotion regulation would affect prediction error-related neural activity in the striatum and ventral tegmental area, reflecting an emotion regulation-related modulation of learning. Our results show that cognitive emotion regulation reduced emotion-related brain activity, but increased prediction error-related activity in a network involving ventral tegmental area, hippocampus, insula and ventral striatum. While the reduction of response activity was related to behavioral measures of emotion regulation success, the enhancement of prediction error-related neural activity was related to learning performance. Furthermore, functional connectivity between the ventral tegmental area and ventrolateral prefrontal cortex, an area involved in regulation, was specifically increased during emotion regulation and likewise related to learning performance. Our data, therefore, provide first-time evidence that beyond reducing emotional responses, cognitive emotion regulation affects learning by enhancing prediction error-related activity, potentially via tegmental dopaminergic pathways. Copyright © 2015 Elsevier Inc. All rights reserved.

  18. Ginsenoside Rh2 enhances the antitumor immunological response of a melanoma mice model.

    Science.gov (United States)

    Wang, Meng; Yan, Shi-Ju; Zhang, Hong-Tao; Li, Nan; Liu, Tao; Zhang, Ying-Long; Li, Xiao-Xiang; Ma, Qiong; Qiu, Xiu-Chun; Fan, Qing-Yu; Ma, Bao-An

    2017-02-01

    The treatment of malignant tumors following surgery is important in preventing relapse. Among all the post-surgery treatments, immunomodulators have demonstrated satisfactory effects on preventing recurrence according to recent studies. Ginsenoside is a compound isolated from panax ginseng, which is a famous traditional Chinese medicine. Ginsenoside aids in killing tumor cells through numerous processes, including the antitumor processes of ginsenoside Rh2 and Rg1, and also affects the inflammatory processes of the immune system. However, the role that ginsenoside serves in antitumor immunological activity remains to be elucidated. Therefore, the present study aimed to analyze the effect of ginsenoside Rh2 on the antitumor immunological response. With a melanoma mice model, ginsenoside Rh2 was demonstrated to inhibit tumor growth and improved the survival time of the mice. Ginsenoside Rh2 enhanced T-lymphocyte infiltration in the tumor and triggered cytotoxicity in spleen lymphocytes. In addition, the immunological response triggered by ginsenoside Rh2 could be transferred to other mice. In conclusion, the present study provides evidence that ginsenoside Rh2 treatment enhanced the antitumor immunological response, which may be a potential therapy for melanoma.

  19. Stimuli-Responsive Nanodiamond-Based Biosensor for Enhanced Metastatic Tumor Site Detection.

    Science.gov (United States)

    Wang, Xin; Gu, Mengjie; Toh, Tan Boon; Abdullah, Nurrul Lissa Binti; Chow, Edward Kai-Hua

    2018-02-01

    Metastasis is often critical to cancer progression and linked to poor survival and drug resistance. Early detection of metastasis, as well as identification of metastatic tumor sites, can improve cancer patient survival. Thus, developing technology to improve the detection of cancer metastasis biomarkers can improve both diagnosis and treatment. In this study, we investigated the use of nanodiamonds to develop a stimuli-responsive metastasis detection complex that utilizes matrix metalloproteinase 9 (MMP9) as a metastasis biomarker, as MMP9 increased expression has been shown to be indicative of metastasis. The nanodiamond-MMP9 biosensor complex consists of nanodiamonds functionalized with MMP9-specific fluorescent-labeled substrate peptides. Using this design, protease activity of MMP9 can be accurately measured and correlated to MMP9 expression. The nanodiamond-MMP9 biosensor also demonstrated an enhanced ability to protect the base sensor peptide from nonspecific serum protease cleavage. This enhanced peptide stability, combined with a quantitative stimuli-responsive output function, provides strong evidence for the further development of a nanodiamond-MMP9 biosensor for metastasis site detection. More importantly, this work provides the foundation for use of nanodiamonds as a platform for stimuli-responsive biosensors and theranostic complexes that can be implemented across a wide range of biomedical applications.

  20. Enhanced Response Speed of ZnO Nanowire Photodetector by Coating with Photoresist

    Directory of Open Access Journals (Sweden)

    Xing Yang

    2016-01-01

    Full Text Available Spin-coating photoresist film on ZnO nanowire (NW was introduced into the fabrication procedure to improve photoresponse and recovery speed of a ZnO NW ultraviolet photoelectric detector. A ZnO NW was first assembled on prefabricated electrodes by dielectrophoresis. Then, photoresist was spin-coated on the nanowire. Finally, a metal layer was electrodeposited on the nanowire-electrode contacts. The response properties and I-V characteristics of ZnO NW photodetector were investigated by measuring the electrical current under different conditions. Measurement results demonstrated that the detector has an enhanced photoresponse and recovery speed after coating the nanowire with photoresist. The photoresponse and recovery characteristics of detectors with and without spin-coating were compared to demonstrate the effects of photoresist and the enhancement of response and recovery speed of the photodetector is ascribed to the reduced surface absorbed oxygen molecules and binding effect on the residual oxygen molecules after photoresist spin-coating. The results demonstrated that surface coating may be an effective and simple way to improve the response speed of the photoelectric device.

  1. Enhancement of mucosal immune responses by chimeric influenza HA/SHIV virus-like particles

    International Nuclear Information System (INIS)

    Guo Lizheng; Lu Xiaoyan; Kang, S.-M.; Chen Changyi; Compans, Richard W.; Yao Qizhi

    2003-01-01

    To enhance mucosal immune responses using simian/human immunodeficiency virus-like particles (SHIV VLPs), we have produced novel phenotypically mixed chimeric influenza HA/SHIV VLPs and used them to immunize C57BL/6J mice intranasally. Antibody and cytotoxic T-cell (CTL) responses as well as cytokine production in both systemic and mucosal sites were compared after immunization with SHIV VLPs or chimeric HA/SHIV VLPs. By using enzyme-linked immunosorbent assay (ELISA), the levels of serum IgG and mucosal IgA to the HIV envelope protein (Env) were found to be highest in the group immunized with chimeric HA/SHIV VLPs. Furthermore, the highest titer of serum neutralizing antibody against HIV Env was found with the group immunized with chimeric HA/SHIV VLPs. Analysis of the IgG1/IgG2a ratio indicated that a T H 1-oriented immune response resulted from these VLP immunizations. HA/SHIV VLP-immunized mice also showed significantly higher CTL responses than those observed in SHIV VLP-immunized mice. Moreover, a MHC class I restricted T-cell activation ELISPOT assay showed a mixed type of T H 1/T H 2 cytokines in the HA/SHIV VLP-immunized mice, indicating that the chimeric VLPs can enhance both humoral and cellular immune responses to the HIV Env protein at multiple mucosal and systemic sites. The results indicate that incorporation of influenza HA into heterotypic VLPs may be highly effective for targeting vaccines to mucosal surfaces

  2. Equal pain – Unequal fear response: Enhanced susceptibility of tooth pain to fear conditioning

    Directory of Open Access Journals (Sweden)

    Michael Lukas Meier

    2014-07-01

    Full Text Available Experimental fear conditioning in humans is widely used as a model to investigate the neural basis of fear learning and to unravel the pathogenesis of anxiety disorders. It has been observed that fear conditioning depends on stimulus salience and subject vulnerability to fear. It is further known that the prevalence of dental-related fear and phobia is exceedingly high in the population. Dental phobia is unique as no other body part is associated with a specific phobia. Therefore, we hypothesized that painful dental stimuli exhibit an enhanced susceptibility to fear conditioning when comparing to equal perceived stimuli applied to other body sites. Differential susceptibility to pain-related fear was investigated by analyzing responses to an unconditioned stimulus (UCS applied to the right maxillary canine (UCS-c versus the right tibia (UCS-t. For fear conditioning, UCS-c and USC-t consisted of painful electric stimuli, carefully matched at both application sites for equal intensity and quality perception. UCSs were paired to simple geometrical forms which served as conditioned stimuli (CS+. Unpaired CS+ were presented for eliciting and analyzing conditioned fear responses. Outcome parameter were 1 skin conductance changes and 2 time-dependent brain activity (BOLD responses in fear-related brain regions such as the amygdala, anterior cingulate cortex, insula, thalamus, orbitofrontal cortex and medial prefrontal cortex.A preferential susceptibility of dental pain to fear conditioning was observed, reflected by heightened skin conductance responses and enhanced time-dependent brain activity (BOLD responses in the fear network. For the first time, this study demonstrates fear-related neurobiological mechanisms that point towards a superior conditionability of tooth pain. Beside traumatic dental experiences our results offer novel evidence that might explain the high prevalence of dental-related fears in the population.

  3. Features of energetic particle radial profiles inferred from geosynchronous responses to solar wind dynamic pressure enhancements

    Directory of Open Access Journals (Sweden)

    Y. Shi

    2009-02-01

    Full Text Available Determination of the radial profile of phase space density of relativistic electrons at constant adiabatic invariants is crucial for identifying the source for them within the outer radiation belt. The commonly used method is to convert flux observed at fixed energy to phase space density at constant first, second and third adiabatic invariants, which requires an empirical global magnetic field model and thus might produce some uncertainties in the final results. From a different perspective, in this paper we indirectly infer the shape of the radial profile of phase space density of relativistic electrons near the geosynchronous region by statistically examining the geosynchronous energetic flux response to 128 solar wind dynamic pressure enhancements during the years 2000 to 2003. We thus avoid the disadvantage of using empirical magnetic field models. Our results show that the flux response is species and energy dependent. For protons and low-energy electrons, the primary response to magnetospheric compression is an increase in flux at geosynchronous orbit. For relativistic electrons, the dominant response is a decrease in flux, which implies that the phase space density decreases toward increasing radial distance at geosynchronous orbit and leads to a local peak inside of geosynchronous orbit. The flux response of protons and non-relativistic electrons could result from a phase density that increases toward increasing radial distance, but this cannot be determined for sure due to the particle energization associated with pressure enhancements. Our results for relativistic electrons are consistent with previous results obtained using magnetic field models, thus providing additional confirmation that these results are correct and indicating that they are not the result of errors in their selected magnetic field model.

  4. Driving p53 Response to Bax Activation Greatly Enhances Sensitivity to Taxol by Inducing Massive Apoptosis

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    Paola De Feudis

    2000-05-01

    Full Text Available The proapoptotic gene bax is one of the downstream effectors of p53. The p53 binding site in the bax promoter is less responsive to p53 than the one in the growth arrest mediating gene p21. We introduced the bax gene under the control of 13 copies of a strong p53 responsive element into two ovarian cancer cell lines. The clones expressing bax under the control of p53 obtained from the wild-type (wt p53-expressing cell line A2780 were much more sensitive (500- to 1000-fold to the anticancer agent taxol than the parent cell line, with a higher percentage of cells undergoing apoptosis after drug treatment that was clearly p53-dependent and bax-mediated. Xenografts established in nude mice from one selected clone (A2780/C3 were more responsive to taxol than the parental line and the apoptotic response of A2780/C3 tumors was also increased after treatment. Introduction of the same plasmid into the p53 null SKOV3 cell line did not alter the sensitivity to taxol or the induction of apoptosis. In conclusion, driving the p53 response (after taxol treatment by activating the bax gene rather than the p21 gene results in induction of massive apoptosis, in vitro and in vivo, and greatly enhances sensitivity to the drug.

  5. Astaxanthin decreased oxidative stress and inflammation and enhanced immune response in humans

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    Line Larry L

    2010-03-01

    Full Text Available Abstract Background Astaxanthin modulates immune response, inhibits cancer cell growth, reduces bacterial load and gastric inflammation, and protects against UVA-induced oxidative stress in in vitro and rodent models. Similar clinical studies in humans are unavailable. Our objective is to study the action of dietary astaxanthin in modulating immune response, oxidative status and inflammation in young healthy adult female human subjects. Methods Participants (averaged 21.5 yr received 0, 2, or 8 mg astaxanthin (n = 14/diet daily for 8 wk in a randomized double-blind, placebo-controlled study. Immune response was assessed on wk 0, 4 and 8, and tuberculin test performed on wk 8. Results Plasma astaxanthin increased (P helper, Tcytotoxic or natural killer cells. A higher percentage of leukocytes expressed the LFA-1 marker in subjects given 2 mg astaxanthin on wk 8. Subjects fed 2 mg astaxanthin had a higher tuberculin response than unsupplemented subjects. There was no difference in TNF and IL-2 concentrations, but plasma IFN-γ and IL-6 increased on wk 8 in subjects given 8 mg astaxanthin. Conclusion Therefore, dietary astaxanthin decreases a DNA damage biomarker and acute phase protein, and enhances immune response in young healthy females.

  6. Adjuvant-enhanced CD4 T Cell Responses are Critical to Durable Vaccine Immunity

    Directory of Open Access Journals (Sweden)

    Karen A.O. Martins

    2016-01-01

    Full Text Available Protein-based vaccines offer a safer alternative to live-attenuated or inactivated vaccines but have limited immunogenicity. The identification of adjuvants that augment immunogenicity, specifically in a manner that is durable and antigen-specific, is therefore critical for advanced development. In this study, we use the filovirus virus-like particle (VLP as a model protein-based vaccine in order to evaluate the impact of four candidate vaccine adjuvants on enhancing long term protection from Ebola virus challenge. Adjuvants tested include poly-ICLC (Hiltonol, MPLA, CpG 2395, and alhydrogel. We compared and contrasted antibody responses, neutralizing antibody responses, effector T cell responses, and T follicular helper (Tfh cell frequencies with each adjuvant's impact on durable protection. We demonstrate that in this system, the most effective adjuvant elicits a Th1-skewed antibody response and strong CD4 T cell responses, including an increase in Tfh frequency. Using immune-deficient animals and adoptive transfer of serum and cells from vaccinated animals into naïve animals, we further demonstrate that serum and CD4 T cells play a critical role in conferring protection within effective vaccination regimens. These studies inform on the requirements of long term immune protection, which can potentially be used to guide screening of clinical-grade adjuvants for vaccine clinical development.

  7. Adjuvant-enhanced CD4 T Cell Responses are Critical to Durable Vaccine Immunity.

    Science.gov (United States)

    Martins, Karen A O; Cooper, Christopher L; Stronsky, Sabrina M; Norris, Sarah L W; Kwilas, Steven A; Steffens, Jesse T; Benko, Jacqueline G; van Tongeren, Sean A; Bavari, Sina

    2016-01-01

    Protein-based vaccines offer a safer alternative to live-attenuated or inactivated vaccines but have limited immunogenicity. The identification of adjuvants that augment immunogenicity, specifically in a manner that is durable and antigen-specific, is therefore critical for advanced development. In this study, we use the filovirus virus-like particle (VLP) as a model protein-based vaccine in order to evaluate the impact of four candidate vaccine adjuvants on enhancing long term protection from Ebola virus challenge. Adjuvants tested include poly-ICLC (Hiltonol), MPLA, CpG 2395, and alhydrogel. We compared and contrasted antibody responses, neutralizing antibody responses, effector T cell responses, and T follicular helper (Tfh) cell frequencies with each adjuvant's impact on durable protection. We demonstrate that in this system, the most effective adjuvant elicits a Th1-skewed antibody response and strong CD4 T cell responses, including an increase in Tfh frequency. Using immune-deficient animals and adoptive transfer of serum and cells from vaccinated animals into naïve animals, we further demonstrate that serum and CD4 T cells play a critical role in conferring protection within effective vaccination regimens. These studies inform on the requirements of long term immune protection, which can potentially be used to guide screening of clinical-grade adjuvants for vaccine clinical development.

  8. Spectral Decomposition Algorithm (SDA)

    Data.gov (United States)

    National Aeronautics and Space Administration — Spectral Decomposition Algorithm (SDA) is an unsupervised feature extraction technique similar to PCA that was developed to better distinguish spectral features in...

  9. Diagnostic criteria for chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids (CLIPPERS).

    Science.gov (United States)

    Tobin, W Oliver; Guo, Yong; Krecke, Karl N; Parisi, Joseph E; Lucchinetti, Claudia F; Pittock, Sean J; Mandrekar, Jay; Dubey, Divyanshu; Debruyne, Jan; Keegan, B Mark

    2017-09-01

    Chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids (CLIPPERS) is a central nervous system inflammatory syndrome predominantly affecting the brainstem, cerebellum, and spinal cord. Following its initial description, the salient features of CLIPPERS have been confirmed and expanded upon, but the lack of formalized diagnostic criteria has led to reports of patients with dissimilar features purported to have CLIPPERS. We evaluated clinical, radiological and pathological features of patients referred for suspected CLIPPERS and propose diagnostic criteria to discriminate CLIPPERS from non-CLIPPERS aetiologies. Thirty-five patients were evaluated for suspected CLIPPERS. Clinical and neuroimaging data were reviewed by three neurologists to confirm CLIPPERS by consensus agreement. Neuroimaging and neuropathology were reviewed by experienced neuroradiologists and neuropathologists, respectively, both of whom were blinded to the clinical data. CLIPPERS was diagnosed in 23 patients (18 male and five female) and 12 patients had a non-CLIPPERS diagnosis. CLIPPERS patients' median age of onset was 58 years (interquartile range, 24-72) and were followed a median of 44 months (interquartile range 38-63). Non-CLIPPERS patients' median age of onset was 52 years (interquartile range, 39-59) and were followed a median of 27 months (interquartile range, 14-47). Clinical symptoms of gait ataxia, diplopia, cognitive impairment, and facial paraesthesia did not discriminate CLIPPERS from non-CLIPPERS. Marked clinical and radiological corticosteroid responsiveness was observed in CLIPPERS (23/23), and clinical worsening occurred in all 12 CLIPPERS cases when corticosteroids were discontinued. Corticosteroid responsiveness was common but not universal in non-CLIPPERS [clinical improvement (8/12); radiological improvement (2/12); clinical worsening on discontinuation (3/8)]. CLIPPERS patients had brainstem predominant perivascular gadolinium enhancing

  10. Molecular mechanism of radioadaptive response: A cross-adaptive response for enhanced repair of DNA damage in adapted cells

    International Nuclear Information System (INIS)

    Takaji Ikushima

    1997-01-01

    The radioadaptive response (RAR) has been attributed to the induction of a repair mechanism by low doses of ionizing radiation, but the molecular nature of the mechanism is not yet elucidated. We have characterized RAR in a series of experiments in cultured Chinese hamster V79 cells. A 4-h interval is required for the full expression of RAR, which decays with the progression of cell proliferation. Treatments with inhibitors of poly(ADP-ribose) polymerase, protein- or RNA synthesis, and protein kinase C suppress the RAR expression. The RAR cross-reacts on clastogenic lesions induced by other physical and chemical DNA-damaging agents. The presence of newly synthesised proteins has been detected during the expression period. Experiments performed using single-cell gel electrophoresis provided more direct evidence for a faster and enhaced DNA repair rate in adapted cells. Here, using single-cell gel electrophoresis, a cross-adaptive response has been demonstrated for enhanced repair of DNA damage induced by neocarzinostatin in radio-adapted cells. (author)

  11. RAD9 deficiency enhances radiation induced bystander DNA damage and transcriptomal response

    International Nuclear Information System (INIS)

    Ghandhi, Shanaz A; Ponnaiya, Brian; Panigrahi, Sunil K; Hopkins, Kevin M; Cui, Qingping; Hei, Tom K; Amundson, Sally A; Lieberman, Howard B

    2014-01-01

    Radiation induced bystander effects are an important component of the overall response of cells to irradiation and are associated with human health risks. The mechanism responsible includes intra-cellular and inter-cellular signaling by which the bystander response is propagated. However, details of the signaling mechanism are not well defined. We measured the bystander response of Mrad9 +/+ and Mrad9 −/− mouse embryonic stem cells, as well as human H1299 cells with inherent or RNA interference-mediated reduced RAD9 levels after exposure to 1 Gy α particles, by scoring chromosomal aberrations and micronuclei formation, respectively. In addition, we used microarray gene expression analyses to profile the transcriptome of directly irradiated and bystander H1299 cells. We demonstrated that Mrad9 null enhances chromatid aberration frequency induced by radiation in bystander mouse embryonic stem cells. In addition, we found that H1299 cells with reduced RAD9 protein levels showed a higher frequency of radiation induced bystander micronuclei formation, compared with parental cells containing inherent levels of RAD9. The enhanced bystander response in human cells was associated with a unique transcriptomic profile. In unirradiated cells, RAD9 reduction broadly affected stress response pathways at the mRNA level; there was reduction in transcript levels corresponding to genes encoding multiple members of the UVA-MAPK and p38MAPK families, such as STAT1 and PARP1, suggesting that these signaling mechanisms may not function optimally when RAD9 is reduced. Using network analysis, we found that differential activation of the SP1 and NUPR1 transcriptional regulators was predicted in directly irradiated and bystander H1299 cells. Transcription factor prediction analysis also implied that HIF1α (Hypoxia induced factor 1 alpha) activation by protein stabilization in irradiated cells could be a negative predictor of the bystander response, suggesting that local hypoxic stress

  12. Enhanced subgenual cingulate response to altruistic decisions in remitted major depressive disorder

    Directory of Open Access Journals (Sweden)

    Erdem Pulcu

    2014-01-01

    Conclusions: We showed that altruistic decisions probe residual sgACC hypersensitivity in MDD even after symptoms are fully remitted. The sgACC has previously been shown to be associated with guilt which promotes altruistic decisions. In contrast, the striatum showed common activation to both simple and altruistic rewards and could be involved in the so-called “warm glow” of donation. Enhanced neural response in the depression group, in areas previously linked to altruistic decisions, supports the hypothesis of a possible association between hyper-altruism and depression vulnerability, as shown by recent epidemiological studies.

  13. Metal nanostructures for the enhancement of the Raman response of molecular adsorbates

    Science.gov (United States)

    Giorgetti, Emilia; Giammanco, Francesco; Margheri, Giancarlo; Trigari, Silvana; Muniz-Miranda, Maurizio

    2011-08-01

    Spectroscopic investigation of metallic nanostructures of different size and morphology is presented, with particular focus on the capability of enhancing the Raman response of molecular adsorbates, namely on their SERS properties. In this framework, we describe recent results obtained with Au/Ag nanocages and Au nanostars, which can be used conveniently to shift the extinction spectra and the SERS activity up to the near infrared. In the case of nanostars, we present a synthesis procedure which permits fine tuning of their morphology and extinction, thus allowing preparation of structures with controlled SERS activity from 500 up to 1500 nm.

  14. Modified field enhancement and extinction by plasmonic nanowire dimers due to nonlocal response

    DEFF Research Database (Denmark)

    Toscano, Giuseppe; Raza, Søren; Jauho, Antti-Pekka

    2012-01-01

    We study the effect of nonlocal optical response on the optical properties of metallic nanowires, by numerically implementing the hydrodynamical Drude model for arbitrary nanowire geometries. We first demonstrate the accuracy of our frequency-domain finite-element implementation by benchmarking...... it in a wide frequency range against analytical results for the extinction cross section of a cylindrical plasmonic nanowire. Our main results concern more complex geometries, namely cylindrical and bow-tie nanowire dimers that can strongly enhance optical fields. For both types of dimers we find that nonlocal...

  15. Responses of evergreen and deciduous Quercus species to enhanced ozone levels

    International Nuclear Information System (INIS)

    Calatayud, Vicent; Cervero, Julia; Calvo, Esperanza; Garcia-Breijo, Francisco-Jose; Reig-Arminana, Jose; Sanz, Maria Jose

    2011-01-01

    Plants of one evergreen oak (Quercus ilex) and three deciduous oaks (Q. faginea, with small leaves; Q. pyrenaica and Q. robur, with large leaves) were exposed both to filtered air and to enhanced ozone levels in Open-Top Chambers. Q. faginea and Q. pyrenaica were studied for the first time. Based on visible injury, gas exchange, chlorophyll content and biomass responses, Q. pyrenaica was the most sensitive species, and Q. ilex was the most tolerant, followed by Q. faginea. Functional leaf traits of the species were related to differences in sensitivity, while accumulated ozone flux via stomata (POD 1.6 ) partly contributed to the observed differences. For risk assessment of Mediterranean vegetation, the diversity of responses detected in this study should be taken into account, applying appropriate critical levels. - Ozone tolerance overlapped with leaf traits in four Quercus species.

  16. Responses of evergreen and deciduous Quercus species to enhanced ozone levels

    Energy Technology Data Exchange (ETDEWEB)

    Calatayud, Vicent, E-mail: calatayud_viclor@gva.e [Instituto Universitario CEAM-UMH, Charles R. Darwin 14, Parc Tecnologic, 46980 Paterna, Valencia (Spain); Cervero, Julia; Calvo, Esperanza [Instituto Universitario CEAM-UMH, Charles R. Darwin 14, Parc Tecnologic, 46980 Paterna, Valencia (Spain); Garcia-Breijo, Francisco-Jose [Laboratorio de Anatomia e Histologia Vegetal ' Julio Iranzo' , Jardin Botanico, Universitat de Valencia, c/Quart 80, 46008 Valencia (Spain); Departamento de Ecosistemas Agroforestales, Escuela Tecnica Superior del Medio Rural y Enologia, Universidad Politecnica de Valencia, Avda. Blasco Ibanez 21, 46010 Valencia (Spain); Reig-Arminana, Jose [Departamento de Ecosistemas Agroforestales, Escuela Tecnica Superior del Medio Rural y Enologia, Universidad Politecnica de Valencia, Avda. Blasco Ibanez 21, 46010 Valencia (Spain); Sanz, Maria Jose [Instituto Universitario CEAM-UMH, Charles R. Darwin 14, Parc Tecnologic, 46980 Paterna, Valencia (Spain)

    2011-01-15

    Plants of one evergreen oak (Quercus ilex) and three deciduous oaks (Q. faginea, with small leaves; Q. pyrenaica and Q. robur, with large leaves) were exposed both to filtered air and to enhanced ozone levels in Open-Top Chambers. Q. faginea and Q. pyrenaica were studied for the first time. Based on visible injury, gas exchange, chlorophyll content and biomass responses, Q. pyrenaica was the most sensitive species, and Q. ilex was the most tolerant, followed by Q. faginea. Functional leaf traits of the species were related to differences in sensitivity, while accumulated ozone flux via stomata (POD{sub 1.6}) partly contributed to the observed differences. For risk assessment of Mediterranean vegetation, the diversity of responses detected in this study should be taken into account, applying appropriate critical levels. - Ozone tolerance overlapped with leaf traits in four Quercus species.

  17. Enhanced bake-hardening response of an Al–Mg–Si–Cu alloy with Zn addition

    Energy Technology Data Exchange (ETDEWEB)

    Guo, M.X., E-mail: mingxingguo@skl.ustb.edu.cn [State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083 (China); Sha, G., E-mail: gang.sha@njust.edu.cn [School of Materials Science and Engineering, Nanjing University of Science and Technology, Jiangsu 210094 (China); Cao, L.Y. [State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083 (China); Liu, W.Q. [Key Laboratory for Microstructures, Shanghai University, Shanghai 200444 (China); Zhang, J.S.; Zhuang, L.Z. [State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083 (China)

    2015-07-15

    This study reports that Zn addition greatly enhances the bake-hardening response of an Al–Mg–Si–Cu alloy. The pre-aged alloy exhibits a high strength increment of 135 MPa after paint baking. Differential scanning calorimetry, atom probe tomography and high-resolution transmission electron microscopy reveal that Zn addition and pre-aging have significant effects on the solute nanostructure formation. Zn atoms partition into solute clusters/GP zones, and reduce the activation energy of β” precipitation in the alloy. - Highlights: • Zn addition can improve the bake-hardening response of an Al–Mg–Si–Cu alloy. • Zn addition can stabilize the solute clusters/GP zones from dissolution. • Zn addition can reduce the size of clusters formed in the pre-aging treatment. • Zn partitioned into solute clusters/GP zones and β” in the Zn-containing Al alloy.

  18. Conformable amplified lead zirconate titanate sensors with enhanced piezoelectric response for cutaneous pressure monitoring.

    Science.gov (United States)

    Dagdeviren, Canan; Su, Yewang; Joe, Pauline; Yona, Raissa; Liu, Yuhao; Kim, Yun-Soung; Huang, YongAn; Damadoran, Anoop R; Xia, Jing; Martin, Lane W; Huang, Yonggang; Rogers, John A

    2014-08-05

    The ability to measure subtle changes in arterial pressure using devices mounted on the skin can be valuable for monitoring vital signs in emergency care, detecting the early onset of cardiovascular disease and continuously assessing health status. Conventional technologies are well suited for use in traditional clinical settings, but cannot be easily adapted for sustained use during daily activities. Here we introduce a conformal device that avoids these limitations. Ultrathin inorganic piezoelectric and semiconductor materials on elastomer substrates enable amplified, low hysteresis measurements of pressure on the skin, with high levels of sensitivity (~0.005 Pa) and fast response times (~0.1 ms). Experimental and theoretical studies reveal enhanced piezoelectric responses in lead zirconate titanate that follow from integration on soft supports as well as engineering behaviours of the associated devices. Calibrated measurements of pressure variations of blood flow in near-surface arteries demonstrate capabilities for measuring radial artery augmentation index and pulse pressure velocity.

  19. Assessing Tumor Response to Treatment in Patients with Lung Cancer Using Dynamic Contrast-Enhanced CT

    DEFF Research Database (Denmark)

    Strauch, Louise S; Eriksen, Rie Ø; Sandgaard, Michael

    2016-01-01

    Reviews and Meta-Analyses (PRISMA) guidelines. Only original research articles concerning treatment response in patients with lung cancer assessed with DCE-CT were included. To assess the validity of each study we implemented Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2). The initial search......The aim of this study was to provide an overview of the literature available on dynamic contrast-enhanced computed tomography (DCE-CT) as a tool to evaluate treatment response in patients with lung cancer. This systematic review was compiled according to Preferred Reporting Items for Systematic...... yielded 651 publications, and 16 articles were included in this study. The articles were divided into groups of treatment. In studies where patients were treated with systemic chemotherapy with or without anti-angiogenic drugs, four out of the seven studies found a significant decrease in permeability...

  20. Negotiation of gender responsibilities in resettled refugee populations through Relationship Enhancement training.

    Science.gov (United States)

    Bellinger, Goli Amin

    2013-06-01

    Being uprooted, displaced, and resettled can produce great tension in refugee marriages. This paper details a technique to help refugees recognize and manage changes and threats to traditional gender roles after resettlement to western countries. A case study from a multisite psycho-educational marriage project illustrates the application of the Relationship Enhancement model with a Bhutanese couple. Through empathy and structured dialogue, the couple is coached to identify their core concerns about the changes in their lives and come up with mutually beneficial solutions. Focusing on the redistribution of each gender's prescribed responsibilities allows the clinician to respond to the cultural structuring of equitable division of labor while helping families to address new responsibilities in managing household duties, parenting, employment, and finances.

  1. Evaluation of Macular Ganglion Cell-inner Plexiform Layer and Choroid in Psoriasis Patients Using Enhanced Depth Imaging Spectral Domain Optical Coherence Tomography.

    Science.gov (United States)

    Ersan, Ismail; Kilic, Sevilay; Arikan, Sedat; Kara, Selcuk; Işik, Selda; Gencer, Baran; Ogretmen, Zerrin

    2017-08-01

    To evaluate changes in the thickness of the central macula, macular ganglion cell-inner plexiform layer (mGCIPL), and subfoveal choroid in patients with psoriasis using spectral domain optical coherence tomography (SD-OCT). The measurements of macular, mGCIPL thicknesses and subfoveal choroidal thickness (SFCT) obtained by SD-OCT of psoriasis patients (n = 46). These measurements were compared with those of 50 healthy controls. The macular, mGCIPL, and choroidal thicknesses did not differ between the controls and psoriatic subjects (p>0.05). When the patients were divided into two distinct groups, only the SFCT was significantly thicker in the severe psoriasis group compared with the mild psoriasis group (p = 0.003). These findings suggest that choroidal alterations are seen without macular changes in patients with psoriasis. Severe psoriasis appears to be related to increases in SFCT as a consequence of possible inflammatory cascades that are part of the disease's pathogenesis.

  2. Photoreceptor spectral sensitivity of the compound eyes of black soldier fly (Hermetia illucens) informing the design of LED-based illumination to enhance indoor reproduction.

    Science.gov (United States)

    Oonincx, D G A B; Volk, N; Diehl, J J E; van Loon, J J A; Belušič, G

    2016-12-01

    Mating in the black soldier fly (BSF) is a visually mediated behaviour that under natural conditions occurs in full sunlight. Artificial light conditions promoting mating by BSF were designed based on the spectral characteristics of the compound eye retina. Electrophysiological measurements revealed that BSF ommatidia contained UV-, blue- and green-sensitive photoreceptor cells, allowing trichromatic vision. An illumination system for indoor breeding based on UV, blue and green LEDs was designed and its efficiency was compared with illumination by fluorescent tubes which have been successfully used to sustain a BSF colony for five years. Illumination by LEDs and the fluorescent tubes yielded equal numbers of egg clutches, however, the LED illumination resulted in significantly more larvae. The possibilities to optimize the current LED illumination system to better approximate the skylight illuminant and potentially optimize the larval yield are discussed. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. The response of macroinvertebrates to artificially enhanced detritus levels in plantation streams

    Directory of Open Access Journals (Sweden)

    J. L. Pretty

    2004-01-01

    Full Text Available The leaves and wood from vegetation surrounding headwater streams constitute a major food source for aquatic invertebrates, providing they are retained upon the streambed and not transported downstream. This study investigated the response of aquatic invertebrates to artificially increased detritus retention, in an effort to reproduce the naturally occurring build up of dead organic matter associated with streams in old-growth forest. The background detrital standing stock in streams in Kielder Forest (Northumberland, UK was low, approximately 32 gm-2. Two streams flowing through dense conifer plantation and one in open broadleaved woodland were manipulated by the addition of logs over a 10 m stream reach. After several months, log addition significantly enhanced detrital standing stocks in both conifer and broadleaved streams. Total invertebrate abundance, taxon richness and the numbers of certain numerically dominant families were significantly higher in experimental than reference reaches in both conifer and broadleaved streams. This response was most marked for detritivores, whilst non-detritivore groups often showed no response to the manipulation. Whilst in the short term the responses to enhanced retention may reflect a redistribution of the local fauna, it is argued that over a longer time-scale, a genuine increase in invertebrate density and diversity could occur. Allowing old-growth forest to develop in planted valley bottoms may be a viable management option for conservation. If established alongside streams, it would ensure continuous input of woody material and the fauna may benefit from the resulting increase in detritus retention. Keywords: forestry, detritivores, old-growth conifers, river management, woody debris

  4. Extrinsic response enhancement at the polymorphic phase boundary in piezoelectric materials

    Energy Technology Data Exchange (ETDEWEB)

    Ochoa, Diego A.; García, José E., E-mail: jose.eduardo.garcia@upc.edu [Department of Physics, Universitat Politècnica de Catalunya - BarcelonaTech, Barcelona 08034 (Spain); Esteves, Giovanni; Jones, Jacob L. [Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27696 (United States); Rubio-Marcos, Fernando; Fernández, José F. [Department of Electroceramics, Instituto de Cerámica y Vidrio - CSIC, Madrid 28049 (Spain)

    2016-04-04

    Polymorphic phase boundaries (PPBs) in piezoelectric materials have attracted significant interest in recent years, in particular, because of the unique properties that can be found in their vicinity. However, to fully harness their potential as micro-nanoscale functional entities, it is essential to achieve reliable and precise control of their piezoelectric response, which is due to two contributions known as intrinsic and extrinsic. In this work, we have used a (K,Na)NbO{sub 3}-based lead-free piezoceramic as a model system to investigate the evolution of the extrinsic contribution around a PPB. X-ray diffraction measurements are performed over a wide range of temperatures in order to determine the structures and transitions. The relevance of the extrinsic contribution at the PPB region is evaluated by means of nonlinear dielectric response measurements. Though it is widely appreciated that certain intrinsic properties of ferroelectric materials increase as PPBs are approached, our results demonstrate that the extrinsic contribution also maximizes. An enhancement of the extrinsic contribution is therefore also responsible for improving the functional properties at the PPB region. Rayleigh's law is used to quantitatively analyze the nonlinear response. As a result, an evolution of the domain wall motion dynamics through the PPB region is detected. This work demonstrates that the extrinsic contribution at a PPB may have a dynamic role in lead-free piezoelectric materials, thereby exerting a far greater influence on their functional properties than that considered to date.

  5. Enhanced prefrontal function with pharmacotherapy on a response inhibition task in adolescent bipolar disorder.

    Science.gov (United States)

    Pavuluri, Mani N; Passarotti, Alessandra M; Harral, Erin M; Sweeney, John A

    2010-11-01

    The aim of the current study is to determine whether pharmacotherapy normalizes cognitive circuitry function supporting voluntary behavioral inhibition in adolescent bipolar disorder. Healthy controls and unmedicated patients with DSM-IV adolescent bipolar disorder in manic, mixed, or hypomanic episodes were matched on demographics and IQ (n = 13 per group; mean age = 14.4 ± 2.4 years). Functional magnetic resonance imaging studies were performed at baseline and after 14 weeks, during which time patients with adolescent bipolar disorder were treated initially with second-generation antipsychotics (SGAs) followed by lamotrigine monotherapy. The primary outcome measure was a Response Inhibition Task, which involved a planned motor response, already "on the way" to execution, that had to be voluntarily inhibited by the subjects in the trials in which a stop signal was presented. There were 6 blocks, each with a predominant rate of either "go" or "stop" trials. The study was conducted from June 2006 through July 2009. All patients showed significant improvement (P adolescent bipolar disorder group than in healthy controls. Increased ventrolateral prefrontal cortex function was related to clinical treatment response. Treatment with SGAs followed by lamotrigine monotherapy enhanced prefrontal and temporal lobe activity during a Response Inhibition Task demonstrating the reversal of disorder-relevant neural circuitry dysfunction in patients with adolescent bipolar disorder. Patient performance was not slowed down with this treatment regimen. clinicaltrials.gov Identifier: NCT00176228. © Copyright 2010 Physicians Postgraduate Press, Inc.

  6. Thermal-Responsive Polymers for Enhancing Safety of Electrochemical Storage Devices.

    Science.gov (United States)

    Yang, Hui; Leow, Wan Ru; Chen, Xiaodong

    2018-03-01

    Thermal runway constitutes the most pressing safety issue in lithium-ion batteries and supercapacitors of large-scale and high-power density due to risks of fire or explosion. However, traditional strategies for averting thermal runaway do not enable the charging-discharging rate to change according to temperature or the original performance to resume when the device is cooled to room temperature. To efficiently control thermal runaway, thermal-responsive polymers provide a feasible and reversible strategy due to their ability to sense and subsequently act according to a predetermined sequence when triggered by heat. Herein, recent research progress on the use of thermal-responsive polymers to enhance the thermal safety of electrochemical storage devices is reviewed. First, a brief discussion is provided on the methods of preventing thermal runaway in electrochemical storage devices. Subsequently, a short review is provided on the different types of thermal-responsive polymers that can efficiently avoid thermal runaway, such as phase change polymers, polymers with sol-gel transitions, and polymers with positive temperature coefficients. The results represent the important development of thermal-responsive polymers toward the prevention of thermal runaway in next-generation smart electrochemical storage devices. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Further neuroendocrine evidence of enhanced vasopressin V3 receptor responses in melancholic depression.

    LENUS (Irish Health Repository)

    Dinan, T G

    2012-02-03

    BACKGROUND: In situations of chronic stress vasopressin plays an important role in regulating the hypothalamic-pituitary adrenal axis. The aim of the current study was to investigate the role of anterior pituitary vasopressin V3 receptors in maintaining the hypercortisolism seen in melancholic depression. METHOD: Fourteen patients with major depression and 14 age- and sex-matched healthy comparison subjects were recruited. Desmopressin (ddAVP) 10 microg was given intravenously and ACTH and cortisol release was monitored for 120 min. RESULTS: The mean +\\/- S.E.M. ACTH response in the depressives was 28.4 +\\/- 4.3 ng\\/l and in the healthy subjects was 18.8 +\\/- 4.9 ng\\/l (P = 0.04). The mean +\\/- S.E.M. cortisol response in the depressives was 261.8 +\\/- 46.5 nmol\\/l and in the healthy subjects was 107.3 +\\/- 26.1 nmol\\/l (P < 0.01). CONCLUSIONS: Patients with major depression have augmented ACTH and cortisol responses to desmopressin indicating enhanced V3 responsivity.

  8. Titania-polymeric powder coatings with nano-topography support enhanced human mesenchymal cell responses.

    Science.gov (United States)

    Mozumder, Mohammad Sayem; Zhu, Jesse; Perinpanayagam, Hiran

    2012-10-01

    Titanium implant osseointegration is dependent on the cellular response to surface modifications and coatings. Titania-enriched nanocomposite polymeric resin coatings were prepared through the application of advanced ultrafine powder coating technology. Their surfaces were readily modified to create nano-rough (topographies that supported human embryonic palatal mesenchymal cell responses. Energy dispersive x-ray spectroscopy confirmed continuous and homogenous coatings with a similar composition and even distribution of titanium. Scanning electron microscopy (SEM) showed complex micro-topographies, and atomic force microscopy revealed intricate nanofeatures and surface roughness. Cell counts, mitochondrial enzyme activity reduction of yellow 3-(4,5-dimethythiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) to dark purple, SEM, and inverted fluorescence microscopy showed a marked increase in cell attachment, spreading, proliferation, and metabolic activity on the nanostructured surfaces. Reverse Transcription- Polymerase Chain Reaction (RT-PCR) analysis showed that type I collagen and Runx2 expression were induced, and Alizarin red staining showed that mineral deposits were abundant in the cell cultures grown on nanosurfaces. This enhancement in human mesenchymal cell attachment, growth, and osteogenesis were attributed to the nanosized surface topographies, roughness, and moderate wetting characteristics of the coatings. Their dimensional similarity to naturally occurring matrix proteins and crystals, coupled with their increased surface area for protein adsorption, may have facilitated the response. Therefore, this application of ultrafine powder coating technology affords highly biocompatible surfaces that can be readily modified to accentuate the cellular response. Copyright © 2012 Wiley Periodicals, Inc.

  9. Evaluation of Radiation Response and Gold Nanoparticle Enhancement in Drug-Resistant Pancreatic Cancer Cells

    Science.gov (United States)

    Abourabia, Assya

    Pancreatic cancer is a major cause of cancer-related death worldwide after lung cancer and colorectal cancer Pancreatic treatment modalities consist of surgery, chemotherapy, and radiation therapy or combination of these therapies. These modalities are good to some extents but they do have some limitations. For example, during the chemotherapy, tumor cells can develop some escape mechanisms and become chemoresistant to protect themselves against the chemo drugs and pass on theses escape mechanisms to their offspring, despite the treatment given. Cancer Cells can become chemoresistant by many mechanisms, for example, decreased drug influx mechanisms, decreased of drug transport molecules, decreased drug activation, altered drug metabolism that diminishes the capacity of cytotoxic drugs, and enhanced repair of DNA damage. Given that some of these chemoresistance mechanisms may impact sensitivity to radiation. Therefore, there is a strong need for a new alternative treatment option to amplify the therapeutic efficacy of radiotherapy and eventually increase the overall efficacy of cancer treatment. Nano-radiation therapy is an emerging and promising modality aims to enhance the therapeutic efficacy of radiotherapy through the use of radiosensitizing nanoparticles. The primary goal of using GNP-enhanced radiation is that GNPs are potent radiosensitizer agents that sensitize the tumor cells to radiation, and these agents promote generation of the free radicals produced by Photo- and Auger- electrons emission at the molecular level which can enhance the effectiveness of radiation-induced cancer cell death. The main aim of this research is to analyze and compare the response to radiation of pancreatic cancer cells, PANC-1, and PANC-1 cells that are resistant to oxaliplatin, PANC-1/OR, and investigate the radiation dose enhancement effect attributable to GNP when irradiating the cells with low-energy (220 kVp) beam at various doses. Based on evidence from the existing

  10. Enhanced ultraviolet photo-response in Dy doped ZnO thin film

    Science.gov (United States)

    Kumar, Pawan; Singh, Ranveer; Pandey, Praveen C.

    2018-02-01

    In the present work, a Dy doped ZnO thin film deposited by the spin coating method has been studied for its potential application in a ZnO based UV detector. The investigations on the structural property and surface morphology of the thin film ensure that the prepared samples are crystalline and exhibit a hexagonal crystal structure of ZnO. A small change in crystallite size has been observed due to Dy doping in ZnO. AFM analysis ascertains the grain growth and smooth surface of the thin films. The Dy doped ZnO thin film exhibits a significant enhancement in UV region absorption as compared to the pure ZnO thin film, which suggests that Dy doped ZnO can be used as a UV detector. Under UV irradiation of wavelength 325 nm, the photocurrent value of Dy doped ZnO is 105.54 μA at 4.5 V, which is 31 times greater than that of the un-doped ZnO thin film (3.39 μA). The calculated value of responsivity is found to increase significantly due to the incorporation of Dy in the ZnO lattice. The observed higher value of photocurrent and responsivity could be attributed to the substitution of Dy in the ZnO lattice, which enhances the conductivity, electron mobility, and defects in ZnO and benefits the UV sensing property.

  11. Phospholipase Dε enhances Braasca napus growth and seed production in response to nitrogen availability.

    Science.gov (United States)

    Lu, Shaoping; Yao, Shuaibing; Wang, Geliang; Guo, Liang; Zhou, Yongming; Hong, Yueyun; Wang, Xuemin

    2016-03-01

    Phospholipase D (PLD), which hydrolyses phospholipids to produce phosphatidic acid, has been implicated in plant response to macronutrient availability in Arabidopsis. This study investigated the effect of increased PLDε expression on nitrogen utilization in Brassica napus to explore the application of PLDε manipulation to crop improvement. In addition, changes in membrane lipid species in response to nitrogen availability were determined in the oil seed crop. Multiple PLDε over expression (PLDε-OE) lines displayed enhanced biomass accumulation under nitrogen-deficient and nitrogen-replete conditions. PLDε-OE plants in the field produced more seeds than wild-type plants but have no impact on seed oil content. Compared with wild-type plants, PLDε-OE plants were enhanced in nitrate transporter expression, uptake and reduction, whereas the activity of nitrite reductase was higher under nitrogen-depleted, but not at nitrogen-replete conditions. The level of nitrogen altered membrane glycerolipid metabolism, with greater impacts on young than mature leaves. The data indicate increased expression of PLDε has the potential to improve crop plant growth and production under nitrogen-depleted and nitrogen-replete conditions. © 2015 Society for Experimental Biology, Association of Applied Biologists and John Wiley & Sons Ltd.

  12. Giant Enhancement of Magnetostrictive Response in Directionally-Solidified Fe83Ga17Erx Compounds

    Directory of Open Access Journals (Sweden)

    Radhika Barua

    2018-06-01

    Full Text Available We report, for the first time, correlations between crystal structure, microstructure and magnetofunctional response in directionally solidified [110]-textured Fe83Ga17Erx (0 < x < 1.2 alloys. The morphology of the doped samples consists of columnar grains, mainly composed of a matrix phase and precipitates of a secondary phase deposited along the grain boundary region. An enhancement of more than ~275% from ~45 to 170 ppm is observed in the saturation magnetostriction value (λs of Fe83Ga17Erx alloys with the introduction of small amounts of Er. Moreover, it was noted that the low field derivative of magnetostriction with respect to an applied magnetic field (i.e., dλs/dHapp for Happ up to 1000 Oe increases by ~230% with Er doping (dλs/dHapp,FeGa= 0.045 ppm/Oe; dλs/dHapp,FeGaEr= 0.15 ppm/Oe. The enhanced magnetostrictive response of the Fe83Ga17Erx alloys is ascribed to an amalgamation of microstructural and electronic factors, namely: (i improved grain orientation and local strain effects due to deposition of Er in the intergranular region; and (ii strong local magnetocrystalline anisotropy, due to the highly anisotropic localized nature of the 4f electronic charge distribution of the Er atom. Overall, this work provides guidelines for further improving galfenol-based materials systems for diverse applications in the power and energy sector.

  13. Emergent Behavior of Arctic Precipitation in Response to Enhanced Arctic Warming

    Science.gov (United States)

    Anderson, Bruce T.; Feldl, Nicole; Lintner, Benjamin R.

    2018-03-01

    Amplified warming of the high latitudes in response to human-induced emissions of greenhouse gases has already been observed in the historical record and is a robust feature evident across a hierarchy of model systems, including the models of the Coupled Model Intercomparison Project Phase 5 (CMIP5). The main aims of this analysis are to quantify intermodel differences in the Arctic amplification (AA) of the global warming signal in CMIP5 RCP8.5 (Representative Concentration Pathway 8.5) simulations and to diagnose these differences in the context of the energy and water cycles of the region. This diagnosis reveals an emergent behavior between the energetic and hydrometeorological responses of the Arctic to warming: in particular, enhanced AA and its associated reduction in dry static energy convergence is balanced to first order by latent heating via enhanced precipitation. This balance necessitates increasing Arctic precipitation with increasing AA while at the same time constraining the magnitude of that precipitation increase. The sensitivity of the increase, 1.25 (W/m2)/K ( 240 (km3/yr)/K), is evident across a broad range of historical and projected AA values. Accounting for the energetic constraint on Arctic precipitation, as a function of AA, in turn informs understanding of both the sign and magnitude of hydrologic cycle changes that the Arctic may experience.

  14. STIMULI-RESPONSIVE POLYMERS WITH ENHANCED EFFICIENCY IN RESERVOIR RECOVERY PROCESSES

    Energy Technology Data Exchange (ETDEWEB)

    Charles McCormick; Roger Hester

    2004-09-30

    This sixth and final progress report for DOE Award Number DE-FC26-01BC15317 describes research during the period March 01, 2004 through August 31, 2004 performed at the University of Southern Mississippi on ''Stimuli Responsive Polymers with Enhanced Efficiency in Reservoir Recovery'' processes. Significantly, terpolymers that are responsive to changes in pH and ionic strength have been synthesized, characterized, and their solution properties have been extensively examined. Terpolymers composed of acrylamide, a carboxylated acrylamido monomer (AMBA), and a quaternary ammonium monomer (AMBATAC) with balanced compositions of the latter two, exhibit increases in aqueous solution viscosity as NaCl concentration is increased. This increase in polymer coil size can be expected upon injection of this type of polymer into oil reservoirs of moderate-to-high salinity, leading to better mobility control. The opposite effect (loss of viscosity) is observed for conventional polymer systems. Additionally polymer mobility characteristics have been conducted for a number of hydrophilic copolymers utilizing an extensional flow apparatus and size exclusion chromatography. This study reveled that oil recovery enhancement through use of polymers in a water flood is due to the polymer's resistance to deformation as it flows through the reservoir. Individual polymers when in aqueous solution form coils. The larger the polymer's coil size, the greater the polymer's resistance to extensional flow and the more effective the polymer is in enhancing oil recovery. Large coil sizes are obtained by increasing the polymer molecular weight and having macromolecular structures that favor greater swelling of the coil by the aqueous solvent conditions (temperature, pH and electrolyte concentration) existing in the reservoir.

  15. Exposure to Experimental Preeclampsia in Mice Enhances the Vascular Response to Future Injury

    Science.gov (United States)

    Pruthi, Dafina; Khankin, Eliyahu V.; Blanton, Robert M.; Aronovitz, Mark; Burke, Suzanne D.; McCurley, Amy; Karumanchi, S. Ananth; Jaffe, Iris Z.

    2015-01-01

    Cardiovascular disease (CVD) remains the leading killer of women in developed nations. One gender-specific risk factor is preeclampsia (PE), a syndrome of hypertension and proteinuria that complicates 5% of pregnancies. Although PE resolves after delivery, exposed women are at increased long term risk of premature CVD and mortality. Preexisting CVD risk factors are associated with increased risk of developing PE but whether PE merely uncovers risk or contributes directly to future CVD remains a critical unanswered question. A mouse PE model was used to test the hypothesis that PE causes an enhanced vascular response to future vessel injury. A PE-like state was induced in pregnant CD1 mice by overexpressing soluble fms-like tyrosine kinase-1 (sFlt-1), a circulating anti-angiogenic protein that induces hypertension and glomerular disease resembling human PE. Two months post-partum, sFlt-1 levels and blood pressure normalized and cardiac size and function by echocardiography and renal histology were indistinguishable in PE-exposed compared to control mice. Mice were then challenged with unilateral carotid injury. PE-exposed mice had significantly enhanced vascular remodeling with increased vascular smooth muscle cell proliferation (180% increase, P<0.01) and vessel fibrosis (216% increase, P<0.001) compared to control pregnancy. In the contralateral uninjured vessel, there was no difference in remodeling after exposure to PE. These data support a new model in which vessels exposed to PE retain a persistently enhanced vascular response to injury despite resolution of PE after delivery. This new paradigm may contribute to the substantially increased risk of CVD in woman exposed to PE. PMID:25712723

  16. Enhanced photoresponsivity in organic field effect transistors by silver nanoparticles

    DEFF Research Database (Denmark)

    Linnet, Jes; Runge Walther, Anders; Albrektsen, Ole

    2017-01-01

    Organic semiconductors (OSC) such as thiophene-based oligomers exhibit useful electronic and optical properties making them applicable in photo-sensing devices. Generally, thiophene-based photodetectors exhibit a decent responsivity with a spectral sensitivity determined by the OSC's absorption...... and shape of the fabricated silver NPs, a spectrally broad enhancement is predicted, which is in agreement with the experimental results. The results show that the photoresponsivity is dominantly enhanced in a spectral region of low OSC absorption coinciding with the localized surface plasmon resonances...

  17. Thermo-responsive polymeric nanoparticles for enhancing neuronal differentiation of human induced pluripotent stem cells.

    Science.gov (United States)

    Seo, Hye In; Cho, Ann-Na; Jang, Jiho; Kim, Dong-Wook; Cho, Seung-Woo; Chung, Bong Geun

    2015-10-01

    We report thermo-responsive retinoic acid (RA)-loaded poly(N-isopropylacrylamide)-co-acrylamide (PNIPAM-co-Am) nanoparticles for directing human induced pluripotent stem cell (hiPSC) fate. Fourier transform infrared spectroscopy and (1)H nuclear magnetic resonance analysis confirmed that RA was efficiently incorporated into PNIAPM-co-Am nanoparticles (PCANs). The size of PCANs dropped with increasing temperatures (300-400 nm at room temperature, 80-90 nm at 37°C) due to its phase transition from hydrophilic to hydrophobic. Due to particle shrinkage caused by this thermo-responsive property of PCANs, RA could be released from nanoparticles in the cells upon cellular uptake. Immunocytochemistry and quantitative real-time polymerase chain reaction analysis demonstrated that neuronal differentiation of hiPSC-derived neuronal precursors was enhanced after treatment with 1-2 μg/ml RA-loaded PCANs. Therefore, we propose that this PCAN could be a potentially powerful carrier for effective RA delivery to direct hiPSC fate to neuronal lineage. The use of induced pluripotent stem cells (iPSCs) has been at the forefront of research in the field of regenerative medicine, as these cells have the potential to differentiate into various terminal cell types. In this article, the authors utilized a thermo-responsive polymer, Poly(N-isopropylacrylamide) (PNIPAM), as a delivery platform for retinoic acid. It was shown that neuronal differentiation could be enhanced in hiPSC-derived neuronal precursor cells. This method may pave a way for future treatment of neuronal diseases. Copyright © 2015 Elsevier Inc. All rights reserved.

  18. Enhanced blue responses in nanostructured Si solar cells by shallow doping

    Science.gov (United States)

    Cheon, Sieun; Jeong, Doo Seok; Park, Jong-Keuk; Kim, Won Mok; Lee, Taek Sung; Lee, Heon; Kim, Inho

    2018-03-01

    Optimally designed Si nanostructures are very effective for light trapping in crystalline silicon (c-Si) solar cells. However, when the lateral feature size of Si nanostructures is comparable to the junction depth of the emitter, dopant diffusion in the lateral direction leads to excessive doping in the nanostructured emitter whereby poor blue responses arise in the external quantum efficiency (EQE). The primary goal of this study is to find the correlation of emitter junction depth and carrier collection efficiency in nanostructured c-Si solar cells in order to enhance the blue responses. We prepared Si nanostructures of nanocone shape by colloidal lithography, with silica beads of 520 nm in diameter, followed by a reactive ion etching process. c-Si solar cells with a standard cell architecture of an Al back surface field were fabricated varying the emitter junction depth. We varied the emitter junction depth by adjusting the doping level from heavy doping to moderate doping to light doping and achieved greatly enhanced blue responses in EQE from 47%-92% at a wavelength of 400 nm. The junction depth analysis by secondary ion mass-spectroscopy profiling and the scanning electron microscopy measurements provided us with the design guide of the doping level depending on the nanostructure feature size for high efficiency nanostructured c-Si solar cells. Optical simulations showed us that Si nanostructures can serve as an optical resonator to amplify the incident light field, which needs to be considered in the design of nanostructured c-Si solar cells.

  19. Enhanced noise tolerance for 10 Gb/s Bi-directional cross-wavelength reuse colorless WDM-PON by using spectrally shaped OFDM signals

    Science.gov (United States)

    Choudhury, Pallab K.

    2018-05-01

    Spectrally shaped orthogonal frequency division multiplexing (OFDM) signal for symmetric 10 Gb/s cross-wavelength reuse reflective semiconductor optical amplifier (RSOA) based colorless wavelength division multiplexed passive optical network (WDM-PON) is proposed and further analyzed to support broadband services of next generation high speed optical access networks. The generated OFDM signal has subcarriers in separate frequency ranges for downstream and upstream, such that the re-modulation noise can be effectively minimized in upstream data receiver. Moreover, the cross wavelength reuse approach improves the tolerance against Rayleigh backscattering noise due to the propagation of different wavelengths in the same feeder fiber. The proposed WDM-PON is successfully demonstrated for 25 km fiber with 16-QAM (quadrature amplitude modulation) OFDM signal having bandwidth of 2.5 GHz for 10 Gb/s operation and subcarrier frequencies in 3-5.5 GHz and DC-2.5 GHz for downstream (DS) and upstream (US) transmission respectively. The result shows that the proposed scheme maintains a good bit error rate (BER) performance below the forward error correction (FEC) limit of 3.8 × 10-3 at acceptable receiver sensitivity and provides a high resilience against re-modulation and Rayleigh backscattering noises as well as chromatic dispersion.

  20. Diminished neural responses predict enhanced intrinsic motivation and sensitivity to external incentive.

    Science.gov (United States)

    Marsden, Karen E; Ma, Wei Ji; Deci, Edward L; Ryan, Richard M; Chiu, Pearl H

    2015-06-01

    The duration and quality of human performance depend on both intrinsic motivation and external incentives. However, little is known about the neuroscientific basis of this interplay between internal and external motivators. Here, we used functional magnetic resonance imaging to examine the neural substrates of intrinsic motivation, operationalized as the free-choice time spent on a task when this was not required, and tested the neural and behavioral effects of external reward on intrinsic motivation. We found that increased duration of free-choice time was predicted by generally diminished neural responses in regions associated with cognitive and affective regulation. By comparison, the possibility of additional reward improved task accuracy, and specifically increased neural and behavioral responses following errors. Those individuals with the smallest neural responses associated with intrinsic motivation exhibited the greatest error-related neural enhancement under the external contingency of possible reward. Together, these data suggest that human performance is guided by a "tonic" and "phasic" relationship between the neural substrates of intrinsic motivation (tonic) and the impact of external incentives (phasic).

  1. Enhancing the stress responses of probiotics for a lifestyle from gut to product and back again

    LENUS (Irish Health Repository)

    2011-08-30

    Abstract Before a probiotic bacterium can even begin to fulfill its biological role, it must survive a battery of environmental stresses imposed during food processing and passage through the gastrointestinal tract (GIT). Food processing stresses include extremes in temperature, as well as osmotic, oxidative and food matrix stresses. Passage through the GIT is a hazardous journey for any bacteria with deleterious lows in pH encountered in the stomach to the detergent-like properties of bile in the duodenum. However, bacteria are equipped with an array of defense mechanisms to counteract intracellular damage or to enhance the robustness of the cell to withstand lethal external environments. Understanding these mechanisms in probiotic bacteria and indeed other bacterial groups has resulted in the development of a molecular toolbox to augment the technological and gastrointestinal performance of probiotics. This has been greatly aided by studies which examine the global cellular responses to stress highlighting distinct regulatory networks and which also identify novel mechanisms used by cells to cope with hazardous environments. This review highlights the latest studies which have exploited the bacterial stress response with a view to producing next-generation probiotic cultures and highlights the significance of studies which view the global bacterial stress response from an integrative systems biology perspective.

  2. Environmentally responsive surface-modified silica nanoparticles for enhanced oil recovery

    International Nuclear Information System (INIS)

    Behzadi, Abed; Mohammadi, Aliasghar

    2016-01-01

    Environmentally responsive surface-modified nanoparticles are colloidal nanoparticles coated with, at least, two physicochemically distinct surface groups. Recent advances in the synthesis and production of nanoparticles have enabled the production of environmentally responsive surface-modified nanoparticles with both hydrophilic and hydrophobic surface groups. These nanoparticles act like colloidal surfactants. In this paper, environmentally responsive surface-modified silica nanoparticles are synthesized and used for enhancement of oil recovery. For this purpose, silica nanoparticles are coated with polyethylene glycol chains as hydrophilic agent and propyl chains as hydrophobic agent at various quantities, and their ability to modulate oil–water interface properties and oil recovery is examined. Oil–water interfacial tension and water surface tension are decreased by 50 % in the presence of silica nanoparticles coated with both agents. Measuring oil-drop contact angle on oil-wetted glass slides and carbonate rock sections, after aging in various surface-modified silica nanofluids, indicates that the wettability of various oil-wetted surfaces is modified from strongly oil-wet to water-wet. Flooding nanofluids to glass micro-models and pore-level investigations demonstrate that surface modification of silica nanoparticles, specially, with both hydrophilic and hydrophobic agents improves considerably their performance in increasing oil recovery and wettability alteration.

  3. Environmentally responsive surface-modified silica nanoparticles for enhanced oil recovery

    Energy Technology Data Exchange (ETDEWEB)

    Behzadi, Abed; Mohammadi, Aliasghar, E-mail: amohammadi@sharif.edu [Sharif University of Technology, Department of Chemical and Petroleum Engineering (Iran, Islamic Republic of)

    2016-09-15

    Environmentally responsive surface-modified nanoparticles are colloidal nanoparticles coated with, at least, two physicochemically distinct surface groups. Recent advances in the synthesis and production of nanoparticles have enabled the production of environmentally responsive surface-modified nanoparticles with both hydrophilic and hydrophobic surface groups. These nanoparticles act like colloidal surfactants. In this paper, environmentally responsive surface-modified silica nanoparticles are synthesized and used for enhancement of oil recovery. For this purpose, silica nanoparticles are coated with polyethylene glycol chains as hydrophilic agent and propyl chains as hydrophobic agent at various quantities, and their ability to modulate oil–water interface properties and oil recovery is examined. Oil–water interfacial tension and water surface tension are decreased by 50 % in the presence of silica nanoparticles coated with both agents. Measuring oil-drop contact angle on oil-wetted glass slides and carbonate rock sections, after aging in various surface-modified silica nanofluids, indicates that the wettability of various oil-wetted surfaces is modified from strongly oil-wet to water-wet. Flooding nanofluids to glass micro-models and pore-level investigations demonstrate that surface modification of silica nanoparticles, specially, with both hydrophilic and hydrophobic agents improves considerably their performance in increasing oil recovery and wettability alteration.

  4. Intermittent hypercapnia induces long-lasting ventilatory plasticity to enhance CO2 responsiveness to overcome dysfunction

    Science.gov (United States)

    Mosher, Bryan Patrick

    The ability of the brain to detect (central CO2 chemosensitivity) and respond to (central CO2 chemoresponsiveness) changes in tissue CO2/pH, is a homeostatic process essential for mammalian life. Dysfunction of the serotonin (5-HT) mechanisms compromises ventilatory CO 2 chemosensitivity/responsiveness and may enhance vulnerability to pathologies such as the Sudden Infant Death Syndrome (SIDS). The laboratory of Dr. Michael Harris has shown medullary raphe contributions to central chemosensitivity involving both 5-HT- and gamma-aminobutyric acid (GABA)-mediated mechanisms. I tested the hypothesis that postnatal exposure to mild intermittent hypercapnia (IHc) induces respiratory plasticity, due in part to strengthening of bicuculline- and saclofen-sensitive mechanisms (GABAA and GABAB receptor antagonists respectively). Rats were exposed to IHc-pretreatment (8 cycles of 5 % CO2) for 5 days beginning at postnatal day 12 (P12). I subsequently assessed CO2 responsiveness using an in situ perfused brainstem preparation. Hypercapnic responses were determined with and without pharmacological manipulation. In addition, IHc-pretreatment effectiveness was tested for its ability to overcome dysfunction in the CO2 responsiveness induced by a dietary tryptophan restriction. This dysfunctional CO2 responsiveness has been suggested to arise from a chronic, partial 5-HT reduction imparted by the dietary restriction. Results show IHc-pretreatment induced plasticity sufficient for CO2 responsiveness despite removal of otherwise critical ketanserin-sensitive mechanisms. CO2 responsiveness following IHc-pretreatment was absent if ketanserin was combined with bicuculline and saclofen, indicating that the plasticity was dependent upon bicuculline- and saclofen-sensitive mechanisms. IHc--induced plasticity was also capable of overcoming the ventilatory defects associated with maternal dietary restriction. Duration of IHc-induced plasticity was also investigated and found to last far into

  5. Enhanced Spectral Analysis of SEP Reservoir Events by OMNIWeb Multi-Source Browse Services of the Space Physics Data Facility and the Virtual Energetic Particle Observatory

    Science.gov (United States)

    Cooper, John F.; Papitashvili, Natalia E.; Johnson, Rita C.; McGuire, Robert

    2015-04-01

    The NASA Space Physics Data Facility and Virtual Energetic Particle Observatory (VEPO) have jointly upgraded the highly used OMNIWeb services for heliospheric solar wind data to also include energetic electron, proton, and heavier ion data in a variety of graphical browse formats. The underlying OMNI and VEPO data now span just over a half century from 1963 to the present. The new services include overlay of differential flux spectra from multiple instruments and spacecraft, scatter plots of fluxes from two user-selected energy channels, distribution function histograms of selected parameters, and spectrograms of flux vs. energy and time. Users can also overlay directional flux spectra from different angular channels. Data from most current and some past (Helios 1&2, Pioneer 10&11) heliospheric spacecraft and instruments are wholly or partially covered by these evolving new services. The traditional OMNI service of correlating magnetic field and plasma data from L1 to 1 AU solar wind sources is also being extended for other spacecraft, e.g. Voyager 1 and 2, to correlations with energetic particle channels. The user capability is, for example, demonstrated to rapidly scan through particle flux spectra from consecutive time periods for so-called “reservoir” events, in which solar energetic particle flux spectra converge in shape and amplitude from multiple spacecraft sources within the inner heliosphere. Such events are important for understanding spectral evolution of global heliospheric events and for intercalibration of flux data from multiple instruments of the same and different spacecraft. These services are accessible at http://omniweb.gsfc.nasa.gov/. SPDF and VEPO are separately accessible at http://spdf.gsfc.nasa.gov/ and http://vepo.gsfc.nasa.gov/.In the future we will propose to extend OMNIWeb particle flux data coverage to the plasma and suprathermal energy range.

  6. Redox-responsive manganese dioxide nanoparticles for enhanced MR imaging and radiotherapy of lung cancer

    Science.gov (United States)

    Cho, Mi Hyeon; Choi, Eun-Seok; Kim, Sehee; Goh, Sung-Ho; Choi, Yongdoo

    2017-12-01

    In this study, we synthesized manganese dioxide nanoparticles (MnO2 NPs) stabilized with biocompatible polymers (polyvinylpyrrolidone and polyacrylic acid) and analyzed their effect on non-small cell lung cancer (NSCLC) cells with or without gefitinib resistance in vitro. MnO2 NPs showed glutathione (GSH)-responsive dissolution and subsequent enhancement in magnetic resonance (MR) imaging. Of note, treatment with MnO2 NPs induced significant cytotoxic effects on NSCLC cells, and additional dose-dependent therapeutic effects were obtained upon X-ray irradiation. Normal cells treated with MnO2 NPs were viable at the tested concentrations. In addition, increased therapeutic efficacy could be achieved when the cells were treated with MnO2 NPs in hypoxic conditions. Therefore, we conclude that the use of MnO2 NPs in MR imaging and combination radiotherapy may be an efficient strategy for the imaging and therapy of NSCLC.

  7. Physiological and behavioral response of stonefly nymphs to enhanced limestone treatment of acid mine drainage

    Energy Technology Data Exchange (ETDEWEB)

    Cole, M.B.; Arnold, D.E.; Watten, B.J. [ABR Inc., PO Box 249, OR (USA). Environmental Research and Services

    2001-07-01

    A new acid mine drainage (AMD) treatment system uses pulsed, fluidized beds of limestone, and carbon dioxide pretreatment of influent AMD to enhance limestone neutralization of AMD. Laboratory studies were carried out to evaluate the behavior and physiology of larval stoneflies (Pteronarcys proteus, Plecoptera) exposed to effluents produced by the treatment system. Survival, sodium balance, drift, and feeding responses by P. proteus to treated and untreated AMD were examined. P. proteus nymphs exhibited significant losses of whole body sodium in exposures to untreated AMD. Nymphs exposed to treated effluents experienced no loss of whole-body sodium. No significant differences in feeding or drift behavior occurred between nymphs exposed to treated effluents and those exposed to AMD-free controls. The treatment system, with and without CO{sub 2} pretreatment, provided water that was not toxic to the test animals, and that allowed normal behavioral and physiological function.