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Sample records for dual-isotope subtraction technique

  1. Vitamin A equivalency and apparent absorption of ß-carotene in ileostomy subjects using a dual-isotope dilution technique

    NARCIS (Netherlands)

    Bouwman, C.A.; Naber, T.H.J.; Breemen, van R.B.; Zhu, D.; Dicke, H.; Siebelink, E.; Hulshof, P.J.M.; Russel, F.G.M.; Schaafsma, G.; West, C.E.

    2010-01-01

    The objective was to quantify the vitamin A equivalency of ß-carotene in two diets using a dual-isotope dilution technique and the apparent ß-carotene absorption as measured by the oral–faecal balance technique. Seventeen healthy adults with an ileostomy completed the 4-week diet-controlled, cross-o

  2. Vitamin A equivalency and apparent absorption of beta-carotene in ileostomy subjects using a dual-isotope dilution technique.

    NARCIS (Netherlands)

    Loo-Bouwman, C.A. Van; Naber, T.H.; Breemen, R.B. van; Zhu, D.; Dicke, H.; Siebelink, E.; Hulshof, P.J.; Russel, F.G.M.; Schaafsma, G.; West, C.E.

    2010-01-01

    The objective was to quantify the vitamin A equivalency of beta-carotene in two diets using a dual-isotope dilution technique and the apparent beta-carotene absorption as measured by the oral-faecal balance technique. Seventeen healthy adults with an ileostomy completed the 4-week diet-controlled, c

  3. Vitamin A equivalency of beta-carotene in healthy adults: limitation of the extrinsic dual-isotope dilution technique to measure matrix effect.

    NARCIS (Netherlands)

    Loo-Bouwman, C.A. Van; West, C.E.; Breemen, R.B. van; Zhu, D.; Siebelink, E.; Versloot, P.; Hulshof, P.J.; Lieshout, Machteld van; Russel, F.G.M.; Schaafsma, G.; Naber, T.H.

    2009-01-01

    Data on the vitamin A equivalency of beta-carotene in food are inconsistent. We quantified the vitamin A equivalency (microg) of beta-carotene in two diets using the dual-isotope dilution technique and the oral-faecal balance technique. A diet-controlled, cross-over intervention study was conducted

  4. Vitamin A equivalency of ß-carotene in healthy adults: limitation of the extrinsic dual-isotope dilution technique to measure matrix effect

    NARCIS (Netherlands)

    Bouwman, C.A.; West, C.E.; Breemen, van R.B.; Zhu, D.; Siebelink, E.; Versloot, P.; Hulshof, P.J.M.; Lieshout, van M.; Russel, F.G.M.; Schaafsma, G.; Naber, T.H.J.

    2009-01-01

    Data on the vitamin A equivalency of ß-carotene in food are inconsistent. We quantified the vitamin A equivalency (¿g) of ß-carotene in two diets using the dual-isotope dilution technique and the oral¿faecal balance technique. A diet-controlled, cross-over intervention study was conducted in twenty-

  5. Vitamin A equivalency and apparent absorption of beta-carotene in ileostomy subjects using a dual-isotope dilution technique.

    Science.gov (United States)

    Van Loo-Bouwman, Carolien A; Naber, Ton H J; van Breemen, Richard B; Zhu, Dongwei; Dicke, Heleen; Siebelink, Els; Hulshof, Paul J M; Russel, Frans G M; Schaafsma, Gertjan; West, Clive E

    2010-06-01

    The objective was to quantify the vitamin A equivalency of beta-carotene in two diets using a dual-isotope dilution technique and the apparent beta-carotene absorption as measured by the oral-faecal balance technique. Seventeen healthy adults with an ileostomy completed the 4-week diet-controlled, cross-over intervention study. Each subject followed both diets for 2 weeks: a diet containing vegetables low in beta-carotene content with supplemental beta-carotene in salad dressing oil ('oil diet'; mean beta-carotene intake 3.1 mg/d) and a diet containing vegetables and fruits high in beta-carotene content ('mixed diet'; mean beta-carotene intake 7.6 mg/d). Daily each subject consumed a mean of 190 microg [13C10]beta-carotene and 195 microg [13C10]retinyl palmitate in oil capsules. The vitamin A equivalency of beta-carotene was calculated as the dose-corrected ratio of [13C5]retinol to [13C10]retinol in serum. Apparent absorption of beta-carotene was determined with oral-faecal balance. Isotopic data quantified a vitamin A equivalency of [13C10]beta-carotene in oil of 3.6:1 (95 % CI 2.8, 4.6) regardless of dietary matrices differences. The apparent absorption of (labelled and dietary) beta-carotene from the 'oil diet' (30 %) was 1.9-fold higher than from the 'mixed diet' (16 %). This extrinsic labelling technique can measure precisely the vitamin A equivalency of beta-carotene in oil capsules, but it does not represent the effect of different dietary matrices.

  6. A Prospective Comparative Study of Parathyroid Dual-Phase Scintigraphy, Dual-Isotope Subtraction Scintigraphy, 4D-CT, and Ultrasonography in Primary Hyperparathyroidism

    DEFF Research Database (Denmark)

    Krakauer, Martin; Wieslander, Bente; Myschetzky, Peter Sand

    2016-01-01

    PURPOSE: Preoperative localization of the diseased parathyroid gland(s) in primary hyperparathyroidism allows for minimally invasive surgery. This study was designed to establish the optimal first-line preoperative imaging modality. PATIENTS AND METHODS: Ninety-one patients were studied...... standard. RESULTS: Ninety-seven hyperfunctioning parathyroid glands (HPGs) were identified by the reference standard. Sensitivity and specificity for subtraction PS, dual-phase PS, 4D-CT, and US were 93%, 65%, 58%, and 57% as well as 99%, 99.6%, 86%, and 95%, respectively. Interrater agreement...

  7. Vitamin A equivalency of beta-carotene in healthy adults: limitation of the extrinsic dual-isotope dilution technique to measure matrix effect.

    Science.gov (United States)

    Van Loo-Bouwman, Carolien A; West, Clive E; van Breemen, Richard B; Zhu, Dongwei; Siebelink, Els; Versloot, Pieter; Hulshof, Paul J M; van Lieshout, Machteld; Russel, Frans G M; Schaafsma, Gertjan; Naber, Ton H J

    2009-06-01

    Data on the vitamin A equivalency of beta-carotene in food are inconsistent. We quantified the vitamin A equivalency (microg) of beta-carotene in two diets using the dual-isotope dilution technique and the oral-faecal balance technique. A diet-controlled, cross-over intervention study was conducted in twenty-four healthy adults. Each subject followed two diets for 3 weeks each: a diet containing vegetables low in beta-carotene with supplemental beta-carotene in salad dressing oil ('oil diet') and a diet containing vegetables and fruits high in beta-carotene ('mixed diet'). During all 6 weeks, each subject daily consumed a mean of 55 (sd 0.5) microg [13C10]beta-carotene and 55 (sd 0.5) microg [13C10]retinyl palmitate in oil capsules. The vitamin A equivalency of beta-carotene was calculated as the dose-corrected ratio of [13C5]retinol to [13C10]retinol in serum and from apparent absorption by oral-faecal balance. Isotopic data quantified a vitamin A equivalency of [13C10]beta-carotene in oil of 3.4 microg (95 % CI 2.8, 3.9), thus the bio-efficacy of the beta-carotene in oil was 28 % in the presence of both diets. However, data from oral-faecal balance estimated vitamin A equivalency as 6:1 microg (95 % CI 4, 7) for beta-carotene in the 'oil diet'. beta-Carotene in the 'oil diet' had 2.9-fold higher vitamin A equivalency than beta-carotene in the 'mixed diet'. In conclusion, this extrinsic labelling technique cannot measure effects of mixed vegetables and fruits matrices, but can measure precisely the vitamin A equivalency of the beta-carotene in oil capsules.

  8. Bi-Event Subtraction Technique at Hadron Colliders

    CERN Document Server

    Dutta, Bhaskar; Kolev, Nikolay; Krislock, Abram

    2011-01-01

    We propose the Bi-Event Subtraction Technique (BEST) as a method of modeling and subtracting large portions of the combinatoric background which arises during reconstruction of particle decay chains at particle colliders. The combinatoric background arises because it is impossible to know experimentally which observed particles come from the decay chain of interest. BEST models this combinatoric background by combining observable particles from different collision events. The combinatoric background modeled by BEST can then be subtracted away, greatly reducing the overall background. This technique can be applied towards two goals of hadron colliders: To improve our understanding of the Standard Model and to search for new physics beyond the Standard Model.

  9. Statistically tuned Gaussian background subtraction technique for UAV videos

    Indian Academy of Sciences (India)

    R Athi Lingam; K Senthil Kumar

    2014-08-01

    Background subtraction is one of the efficient techniques to segment the targets from non-informative background of a video. The traditional background subtraction technique suits for videos with static background whereas the video obtained from unmanned aerial vehicle has dynamic background. Here, we propose an algorithm with tuning factor and Gaussian update for surveillance videos that suits effectively for aerial videos. The tuning factor is optimized by extracting the statistical features of the input frames.With the optimized tuning factor and Gaussian update an adaptive Gaussian-based background subtraction technique is proposed. The algorithm involves modelling, update and subtraction phases. This running Gaussian average based background subtraction technique uses updation at both model generation phase and subtraction phase. The resultant video extracts the moving objects from the dynamic background. Sample videos of various properties such as cluttered background, small objects, moving background and multiple objects are considered for evaluation. The technique is statistically compared with frame differencing technique, temporal median method and mixture of Gaussian model and performance evaluation is done to check the effectiveness of the proposed technique after optimization for both static and dynamic videos.

  10. Evaluation of sacroiliitis: contrast-enhanced MRI with subtraction technique

    Energy Technology Data Exchange (ETDEWEB)

    Algin, Oktay; Gokalp, Gokhan; Baran, Bulent; Ocakoglu, Gokhan; Yazici, Zeynep [Uludag University, Medical Faculty, Department of Radiology, Gorukle, Bursa (Turkey)

    2009-10-15

    The purpose of the study was to investigate the diagnostic value of contrast-enhanced MRI using the subtraction technique in the detection of active sacroiliitis. Magnetic resonance imaging was performed in 8 asymptomatic volunteers and 50 patients with clinically suspected active sacroiliitis. On precontrast MR images, T1-weighted spin-echo images with and without fat saturation (T1WFS and T1W), STIR and 3D-FLASH images with fat saturation were obtained in the semicoronal plane using a 1.5 Tesla imager. Postcontrast MRI was performed using the same T1WFS sequence as before contrast injection for all volunteers and patients. Postcontrast images were subtracted from fat-suppressed precontrast images. Enhancement within the joint space and bone marrow was considered to demonstrate active sacroiliitis. In 50 patients (100 sacroiliac joints [SIJs]), 40 (76 SIJs) were considered to have active sacroiliitis based on MR images. Bone marrow edema was present in 33 patients (62 SIJs) on STIR images. Routine MRI allowed identification of contrast enhancement in SIJs on postcontrast T1WFS images in 31 patients (49 SIJs). Contrast enhancement was observed in 40 patients (76 SIJs) who were examined by MRI using the subtraction technique. Contrast enhancement was significantly more conspicuous on subtraction images than on non-subtracted postcontrast T1WFS images (Mann-Whitney U test, p<0.001). Contrast-enhanced MRI with subtraction technique may be useful for early detection of active sacroiliitis. (orig.)

  11. Dual-isotope measurement of lung water

    Energy Technology Data Exchange (ETDEWEB)

    Chu, R.Y.L.; Carlile, P.V. Jr.; Basmadjian, G. (Oklahoma Univ., Oklahoma City, OK (USA). Health Sciences Center Oklahoma Univ., Oklahoma City, OK (USA). Veterans Administration Medical Center)

    1989-01-01

    Iodine-131-labeled iodo-antipyrine and {sup 99m}Tc-labeled erythrocytes were used to measure water content in lungs. These radioactive tracers were injected into 11 dogs with injured lungs. Blood samples were drawn and the animals sacrificed. The lungs were removed, weighed and homogenized. Samples of blood and lung homogenate were assayed for {sup 131}I and {sup 99m}Tc. Samples were also weighed before and after drying to a constant weight at 70-76{sup 0}C. Extravascular lung water was determined by the dual-isotope technique and again by gravimetric analysis. The average ratio of the results from the two different methods was 1.14{plus minus}0.20. The two methods were also compared by regression analysis and the correlation coefficient was 0.97{plus minus}0.09. (author).

  12. Cutaneous Force Feedback as a Sensory Subtraction Technique in Haptics.

    Science.gov (United States)

    Prattichizzo, D; Pacchierotti, C; Rosati, G

    2012-01-01

    A novel sensory substitution technique is presented. Kinesthetic and cutaneous force feedback are substituted by cutaneous feedback (CF) only, provided by two wearable devices able to apply forces to the index finger and the thumb, while holding a handle during a teleoperation task. The force pattern, fed back to the user while using the cutaneous devices, is similar, in terms of intensity and area of application, to the cutaneous force pattern applied to the finger pad while interacting with a haptic device providing both cutaneous and kinesthetic force feedback. The pattern generated using the cutaneous devices can be thought as a subtraction between the complete haptic feedback (HF) and the kinesthetic part of it. For this reason, we refer to this approach as sensory subtraction instead of sensory substitution. A needle insertion scenario is considered to validate the approach. The haptic device is connected to a virtual environment simulating a needle insertion task. Experiments show that the perception of inserting a needle using the cutaneous-only force feedback is nearly indistinguishable from the one felt by the user while using both cutaneous and kinesthetic feedback. As most of the sensory substitution approaches, the proposed sensory subtraction technique also has the advantage of not suffering from stability issues of teleoperation systems due, for instance, to communication delays. Moreover, experiments show that the sensory subtraction technique outperforms sensory substitution with more conventional visual feedback (VF).

  13. ROBUST TECHNIQUES FOR BACKGROUND SUBTRACTION IN URBAN TRAFFIC VIDEO

    Energy Technology Data Exchange (ETDEWEB)

    Kamath, C; Cheung, S S

    2003-10-28

    Identifying moving objects from a video sequence is a fundamental and critical task in many computer-vision applications. A common approach is to perform background subtraction, which identifies moving objects from the portion of a video frame that differs significantly from a background model. There are many challenges in developing a good background subtraction algorithm. First, it must be robust against changes in illumination. Second, it should avoid detecting non-stationary background objects such as swinging leaves, rain, snow, and shadow cast by moving objects. Finally, its internal background model should react quickly to changes in background such as starting and stopping of vehicles. In this paper, we compare various background subtraction algorithms for detecting moving vehicles and pedestrians in urban traffic video sequences. We consider approaches varying from simple techniques such as frame differencing and adaptive median filtering, to more sophisticated probabilistic modeling techniques. While complicated techniques often produce superior performance, our experiments show that simple techniques such as adaptive median filtering can produce good results with much lower computational complexity.

  14. Momentum-subtraction renormalization techniques in curved space-time

    Energy Technology Data Exchange (ETDEWEB)

    Foda, O.

    1987-10-01

    Momentum-subtraction techniques, specifically BPHZ and Zimmermann's Normal Product algorithm, are introduced as useful tools in the study of quantum field theories in the presence of background fields. In a model of a self-interacting massive scalar field, conformally coupled to a general asymptotically-flat curved space-time with a trivial topology, momentum-subtractions are shown to respect invariance under general coordinate transformations. As an illustration, general expressions for the trace anomalies are derived, and checked by explicit evaluation of the purely gravitational contributions in the free field theory limit. Furthermore, the trace of the renormalized energy-momentum tensor is shown to vanish at the Gell-Mann Low eigenvalue as it should.

  15. Subtracting Technique of Baselines for Capillary Electrophoresis Signals

    Institute of Scientific and Technical Information of China (English)

    WANG Ying; MO Jin-yuan; CHEN Zuan-guang; GAO Yan

    2004-01-01

    The drifting baselines of capillary electrophoresis affect the veracity of analysis greatly. This paper presents Threshold Fitting Technique(TFT) so as to subtract the baselines from the original signals and emendate the signals. In TFT, wav elet and curve fitting technique are applied synthetically, thresholds are decided by the computer automatically. Many experiments of signal processing indicate that TFT is simple for being used, there are few man-induced factors, and the results are satisfactory. TFT can be applied for noisy signals without any pre-processing.

  16. Clinical validation of simultaneous dual-isotope myocardial scintigraphy

    Energy Technology Data Exchange (ETDEWEB)

    Weinmann, Pierre; Moretti, Jean Luc [Department of Nuclear Medicine, Avicenne Hospital, Paris XIII University, 125, Rue de Stalingrad, 93 009 Bobigny Cedex (France); Faraggi, Marc [Department of Nuclear Medicine, Bichat Hospital, Paris VII University (France); Hannequin, Pascal [Centre d' Imagerie Nucleaire, Annecy (France)

    2003-01-01

    Simultaneous dual-isotope (rest thallium-201/stress technetium-99m sestamibi) myocardial single-photon emission tomography (SPET) would be an ideal procedure; however, {sup 99m}Tc cross-talk on the {sup 201}Tl window hampers its routine use. Photon energy recovery (PER) is a spectral deconvolution technique validated for scatter and cross-talk removal in phantom studies and a limited series of patients. In this study we aimed to validate the technique in 295 patients within a context of clinical routine practice. Conventional separate rest {sup 201}Tl myocardial SPET data sets were visually compared with simultaneous dual-isotope data sets corrected by PER. Conventional separate rest {sup 201}Tl data sets were identical to dual PER-corrected {sup 201}Tl data sets in 173 (58.6%) patients. As dual PER {sup 201}Tl data sets are corrected for {sup 99m}Tc cross-talk but also for {sup 201}Tl scatter, they were compared with separate rest {sup 201}Tl data sets corrected by PER in the 122 discordant patients. No difference was found in 77 (26.1%) patients. In 26 (8.8%) patients, the difference consisted in the presence of a defect on dual PER {sup 201}Tl data sets only, mirroring an ischaemic defect on {sup 99m}Tc-sestamibi data sets. This difference can be attributed to the influence of stress on the kinetics of {sup 201}Tl injected at rest. In the remaining 19 (6.4%) patients, the difference between separate and simultaneous PER-corrected data sets was scored as mild in 11 and moderate in eight patients and seemed to be related to multiple methodological factors. It is concluded that PER correctly removes {sup 99m}Tc cross-talk. With the addition of an appropriate attenuation correction, the PER technique may allow the routine use of simultaneous dual-isotope myocardial scintigraphy in the near future. (orig.)

  17. Development of a voxel-matching technique for substantial reduction of subtraction artifacts in temporal subtraction images obtained from thoracic MDCT.

    Science.gov (United States)

    Itai, Yoshinori; Kim, Hyoungseop; Ishikawa, Seiji; Katsuragawa, Shigehiko; Doi, Kunio

    2010-02-01

    A temporal subtraction image, which is obtained by subtraction of a previous image from a current one, can be used for enhancing interval changes (such as formation of new lesions and changes in existing abnormalities) on medical images by removing most of the normal structures. However, subtraction artifacts are commonly included in temporal subtraction images obtained from thoracic computed tomography and thus tend to reduce its effectiveness in the detection of pulmonary nodules. In this study, we developed a new method for substantially removing the artifacts on temporal subtraction images of lungs obtained from multiple-detector computed tomography (MDCT) by using a voxel-matching technique. Our new method was examined on 20 clinical cases with MDCT images. With this technique, the voxel value in a warped (or nonwarped) previous image is replaced by a voxel value within a kernel, such as a small cube centered at a given location, which would be closest (identical or nearly equal) to the voxel value in the corresponding location in the current image. With the voxel-matching technique, the correspondence not only between the structures but also between the voxel values in the current and the previous images is determined. To evaluate the usefulness of the voxel-matching technique for removal of subtraction artifacts, the magnitude of artifacts remaining in the temporal subtraction images was examined by use of the full width at half maximum and the sum of a histogram of voxel values, which may indicate the average contrast and the total amount, respectively, of subtraction artifacts. With our new method, subtraction artifacts due to normal structures such as blood vessels were substantially removed on temporal subtraction images. This computerized method can enhance lung nodules on chest MDCT images without disturbing misregistration artifacts.

  18. A new approach of binary addition and subtraction by non-linear material based switching technique

    Indian Academy of Sciences (India)

    Archan Kumar Das; Partha Partima Das; Sourangshu Mukhopadhyay

    2005-02-01

    Here, we refer a new proposal of binary addition as well as subtraction in all-optical domain by exploitation of proper non-linear material-based switching technique. In this communication, the authors extend this technique for both adder and subtractor accommodating the spatial input encoding system.

  19. Application of the subtraction technique to the radiological diagnosis of temporomandibular joint disorders. On the fundamental studies

    Energy Technology Data Exchange (ETDEWEB)

    Sakurai, Tohru; Tanaka, Toshio; Imaizumi, Satoru; Imaizumi, Eiichi; Yoshihara, Junya; Ohtani, Masatoshi

    1985-02-01

    The oblique lateral transcranial projection (OLTP) of the temporomandibular joint (TMJ) is widely used for the diagnosis of TMJ disease. The OLTP is a simple and valuable technique for the lateral projection of the TMJ, but is sometimes reveals a complex radiographic findings due to the overlapping of the pars petrosa and the mastoid process to the TMJ. We have recently applied a photographic subtraction technique to the OLTP for reduction of the complex radiographic findings in the OLTP. The purpose of this study is to know the value of the photographic subtraction technique in the OLTP fundamentally. The results obtained are as follows: 1) The shape of the condyle was clearly demonstrated by the subtraction technique. 2) Diagnostic ability on disease of the condyle was increased by applying the subtraction technique. 3) Location of the condyle in the fossa was easily detected by the subtraction technique. (author).

  20. Tactile feedback as a sensory subtraction technique in haptics for needle insertion

    CERN Document Server

    Prattichizzo, D; Rosati, G

    2011-01-01

    A sensory substitution technique is presented in which the kinesthetic and tactile feedback are substituted by tactile feedback only provided by two wearable devices able to apply forces to the index finger and thumb holding a handle during a needle insertion task. The force pattern fed back to the user while using the tactile device is similar, in terms of intensity and area of application, to that perceived while interacting with a haptic device providing both tactile and kinesthetic feedback and it can be thought as a subtraction between the complete haptic and kinesthetic feedback. For this reason we refer to this approach as sensory subtraction instead of sensory substitution. A needle insertion scenario is considered. The haptic device is connected to a virtual environment simulating a needle insertion task. Experiments show that the perception of inserting a needle using the tactile feedback only is nearly indistinguishable from the one felt by the user using both tactile and kinesthetic feedback. As m...

  1. A novel quantitative dual-isotope method for simultaneous ventilation and perfusion lung SPET

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez-Crespo, Alejandro; Larsson, Stig A. [Section of Nuclear Medicine, Department of Hospital Physics, Karolinska Hospital, Stockholm (Sweden); Medical Radiation Physics, Department of Oncology-Pathology, Stockholm University and Karolinska Institute, Stockholm (Sweden); Petersson, Johan; Mure, Margareta; Lindahl, Sten G.E. [Department of Anaesthesiology and Intensive Care, Karolinska Hospital, Stockholm (Sweden); Nyren, Sven [Department of Radiology, Karolinska Hospital, Stockholm (Sweden); Glenny, Robb W. [University of Washington School of Medicine, Seattle (United States); Thorell, Jan-Olov [Karolinska Pharmacy, Stockholm (Sweden); Jacobsson, Hans [Section of Nuclear Medicine, Department of Hospital Physics, Karolinska Hospital, Stockholm (Sweden); Department of Radiology, Karolinska Hospital, Stockholm (Sweden)

    2002-07-01

    A quantitative dual-isotope single-photon emission tomography (SPET) technique for the assessment of lung ventilation (V) and perfusion (Q) using, respectively, technetium-99m labelled Technegas (140 keV) and indium-113m labelled macro-aggregated albumin (392 keV), is presented, validated and clinically tested in a healthy volunteer. In order to assess V, Q and V/Q distributions in quantitative terms, algorithms which correct for down scattering, photon scattering and attenuation, as well as an organ outline algorithm, were implemented. Scatter and down-scatter correction were made in the spatial domain by pixel-wise image subtraction of projection-dependent global scattering factors obtained from the energy domain. The attenuation correction was based on an iterative projection/back-projection method. All studies were made on a three-headed SPET system (Trionix) with medium-energy parallel-hole collimators. The set of input data for quantification was based on SPET acquisition of emission data in four separate energy windows, the associated cumulative energy spectra and transmission data. The attenuation correction routine as well as the edge detection algorithm utilized data from {sup 99m}Tc transmission tomography. Attenuation data for {sup 113m}In were obtained by linear scaling of the {sup 99m}Tc attenuation maps. The correction algorithms were experimentally validated with a stack phantom system and applied on a healthy volunteer. The mean difference between the corrected SPET data of the dense stack lung phantom and those obtained from the corresponding scatter- and attenuation-''free'' version was only 1.9% for {sup 99m}Tc and 0.9% for {sup 113m}In. The estimated fractional V/Q distribution in the 3-D lung phantom volume had its peak at V/Q=1, with a width (FWHM) of 0.31 due to noise, particularly in the {sup 113m}In images, and to partial volume effects. For a healthy volunteer, the corresponding values were 0.9 and 0.35, respectively

  2. Multi-slice CT for visualization of acute pulmonary embolism: single breath-hold subtraction technique

    Energy Technology Data Exchange (ETDEWEB)

    Wildberger, J.E.; Mahnken, A.H.; Spuentrup, E.; Guenther, R.W. [Dept. of Diagnostic Radiology, Univ. of Technology, Aachen (Germany); Klotz, E.; Ditt, H. [Siemens Medical Solutions, Computed Tomography, Forchheim (Germany)

    2005-01-01

    Purpose: the purpose of our preliminary animal study was to evaluate the feasibility of a new subtraction technique for visualization of perfusion defects within the lung parenchyma in segmental and subsegmental pulmonary embolism (PE). Materials and methods: in three healthy pigs, PE were artificially induced by fresh human clot material. Within a single breath-hold, CT angiography (CTA) was performed on a 16-slice multi-slice CT scanner (SOMATOM Sensation 16; Siemens, Forchheim, Germany) before and after intravenous application of 80 mL of contrast-medium, followed by a saline chaser. Scan parameters were 120 kV and 100 mAs{sub eff.}, using a collimation of 16 x 1.5 mm and a table speed/rot. of 36 mm (pitch: 1.5; rotation time: 0.5 s). A new 3D subtraction technique was developed, which is based on automated segmentation, non-linear spatial filtering and non-rigid registration. Data were analysed using a color-encoded ''compound view'' of parenchymal enhancement and CTA information displayed in axial, coronal and sagittal orientation. Results: subtraction was technically feasible in all three data sets. The mean scan time for each series was 4.7 s, interscan delay was 14.7 s, respectively. Therefore, an average breath-hold of approximately 24 s was required for the overall scanning procedure. Downstream of occluded segmental and subsegmental arteries, perfusion defects were clearly assessable, showing lower or missing enhancement compared to normally perfused lung parenchyma. In all pigs, additional peripheral areas with triangular shaped perfusion defects were delineated, considered typical for PE. Conclusions: our initial results from the animal model studied slow that perfusion imaging of PE is feasible within a single breath-hold. It allows a comprehensive assessment of perfusion deficits as the direct proof of a pulmonary embolus, can be combined with an indirect visual quantification of the density changes in the adjacent lung tissue

  3. An improved dark-object subtraction technique for atmospheric scattering correction of multispectral data

    Science.gov (United States)

    Chavez, P.S.

    1988-01-01

    Digital analysis of remotely sensed data has become an important component of many earth-science studies. These data are often processed through a set of preprocessing or "clean-up" routines that includes a correction for atmospheric scattering, often called haze. Various methods to correct or remove the additive haze component have been developed, including the widely used dark-object subtraction technique. A problem with most of these methods is that the haze values for each spectral band are selected independently. This can create problems because atmospheric scattering is highly wavelength-dependent in the visible part of the electromagnetic spectrum and the scattering values are correlated with each other. Therefore, multispectral data such as from the Landsat Thematic Mapper and Multispectral Scanner must be corrected with haze values that are spectral band dependent. An improved dark-object subtraction technique is demonstrated that allows the user to select a relative atmospheric scattering model to predict the haze values for all the spectral bands from a selected starting band haze value. The improved method normalizes the predicted haze values for the different gain and offset parameters used by the imaging system. Examples of haze value differences between the old and improved methods for Thematic Mapper Bands 1, 2, 3, 4, 5, and 7 are 40.0, 13.0, 12.0, 8.0, 5.0, and 2.0 vs. 40.0, 13.2, 8.9, 4.9, 16.7, and 3.3, respectively, using a relative scattering model of a clear atmosphere. In one Landsat multispectral scanner image the haze value differences for Bands 4, 5, 6, and 7 were 30.0, 50.0, 50.0, and 40.0 for the old method vs. 30.0, 34.4, 43.6, and 6.4 for the new method using a relative scattering model of a hazy atmosphere. ?? 1988.

  4. Applying Subtractive Hybridization Technique to Enrich and Amplify Tumor-Specific Transcripts of Esophageal Squamous Cell Carcinoma.

    Science.gov (United States)

    Mahmoudian, Reihaneh Alsadat; Abbaszadegan, Mohammad Reza; Gholamin, Mehran

    2017-04-01

    Subtractive hybridization (SH) as an efficient and powerful approach can be applied to isolate differentially expressed transcripts as well as detect of involved mRNAs in various cellular processes, particularly diseases and malignancies. This procedure leads to the enrichment of specific low copy transcripts of tumor cells. Having developed a new approach for SH to isolate tumor specific transcripts, we facilitated discovery of uniquely expressed genes in esophageal squamous cell carcinoma (ESCC). Total RNA was extracted from the fresh tumoral and their adjacent normal tissues, and purified using the Switch Mechanism At the 5' end of Reverse Transcript (SMART) method. Following cDNA synthesis of normal mRNAs using magnetic beads, it was hybridized with tumor mRNAs. To enhance efficiency of subtraction, hybridization was repeated three rounds. Finally, amplification of subtracted tumor-specific transcripts was carried out using in vitro transcription. The subtracted tumoral mRNAs was analyzed quantitatively using real-time PCR for both tumor-specific and housekeeping genes. The subtracted mRNA was confirmed as tumor-specific mRNA pool using RT-PCR and quantitative real-time PCR assessment. The elevated level of tumor-specific transcripts such as MAGE-A4 and CD44 as well as declined copy number of housekeeping genes such as GAPDH, β actin and β2-microglobulin, were confirmed in subtracted tumoral mRNA. The presence of tumor genes was confirmed after the SH procedure. The designed SH method in combination with SMART technique can isolate and amplify high quality tumor-specific transcripts even from small amount of tumor tissues. Removal of common transcripts from the extracted tumoral mRNAs using SH, leads to the enrichment of tumor-specific transcripts. The isolated transcripts are of interest because of their probable roles in ESCC progression and development. In addition, these tumor-specific mRNAs can be applied for future vaccine cancer studies.

  5. Development of twin-illumination and subtraction technique for detection of concave and convex defects on steel surfaces

    Science.gov (United States)

    Ono, Hiroaki; Ogawa, Akihiro; Yamasaki, Takahiro; Koshihara, Takahiro; Kodama, Toshifumi; Iizuka, Yukinori; Oshige, Takahiko

    2016-09-01

    Optical surface inspection of steel mill products such as pipes, plates and slabs usually has the problem of overdetection, which is caused by signals from harmless parts such as scale and surface texture. The authors propose a new inspection technique based on the experience that most harmful defects on these products have a concave or convex shape, whereas most harmless parts that might be overdetected have flat shapes. The proposed technique is called the `twin-illumination and subtraction technique'. In this technique, firstly, two images of the target area on a steel surface illuminated from the two sides are captured, respectively. A subtraction image is then calculated from these images. Comparing the images illuminated from the different sides, the images from concave or convex defects look different due to their different shadows, while images from harmless flat parts look the same because illumination does not cause any shadow. As a result, two images with the same appearances from a harmless part are canceled by subtraction, and two images with different appearances from a concave or convex defect remain even after subtraction. Finally, it is possible to detect only concave or convex defects without overdetecting flat patterns. In this manuscript, first, we explain the proposed technique and confirmation experiments in the laboratory. We also explain a new optical inspection system based on the concept described above and its application to moving hot pipes in a steel manufacturing plant to prove the effectiveness of the technique. We concluded that the inspection system has sufficient performance for use as a practical system.

  6. Evaluation of the rockburst potential in longwall coal mining using passive seismic velocity tomography and image subtraction technique

    Science.gov (United States)

    Hosseini, Navid

    2017-09-01

    Rockburst is a typical dynamic disaster in underground coal mines which its occurrences relate to the mechanical quality of coal seam and surrounding rock mass and also the condition of stress distribution. The main aim of this paper is to study the potential of rockburst in a longwall coal mine by using of passive seismic velocity tomography and image subtraction technique. For this purpose, first by mounting an array of receivers on the surface above the active panel, the mining-induced seismic data as a passive source for several continuous days were recorded. Then, the three-dimensional tomograms using simultaneous iteration reconstruction technique (SIRT) for each day are created and by employing the velocity filtering, the overstressed zones are detected. In addition, the two-dimensional seismic velocity tomograms in coal seam level by slicing the three-dimensional tomograms are obtained. Then the state of stress changes in successive days by applying the image subtraction technique on these two-dimensional tomograms is considered. The results show that the compilation of filtered three-dimensional tomograms and subtracted images is an appropriate approach for detecting the overstressed zones around the panel and subsequent evaluation of rockburst potential. The research conclusion proves that the applied approach in this study in combination with field observations of rock mass status can effectively identify the rockburst-prone areas during the mining operation and help to improve the safety condition.

  7. Subtractive Leadership

    Science.gov (United States)

    Larwin, K. H.; Thomas, Eugene M.; Larwin, David A.

    2015-01-01

    This paper introduces a new term and concept to the leadership discourse: Subtractive Leadership. As an extension of the distributive leadership model, the notion of subtractive leadership refers to a leadership style that detracts from organizational culture and productivity. Subtractive leadership fails to embrace and balance the characteristics…

  8. Bio-Nanofabrication: Structuring Polymer Thin Films via Bacterial S-layer Proteins for Subsequent Use with Subtractive Nanofabrication Techniques

    Science.gov (United States)

    Esch, Mandy B.; Amponsah, Ebenezer K.; Bergkvist, Magnus

    2007-03-01

    Bio-molecule assisted lithography is a novel approach to create ordered patterns on the micro and nanometer size scale on thin films. The technique bears the potential to utilize self assembling properties of bio-molecules and to be integrated with conventional nanofabrication techniques. In the past, bacterial cell wall proteins (S-layers proteins) have been utilized to create ordered nanoparticle arrays. The work presented here employs S-layer proteins to shape UV-curable resist via an S-layer imprinted parylene template. Using this technique we can replicate S-layer patterns in resist thereby rendering the shape more resistant to subtractive nanofabrication techniques. The technique also demonstrates the adequacy of Nano Imprint Lithography to produce complex patterns not achievable with conventional lithography.

  9. Cognitive behaviour modification: a technique for teaching subtraction skills to hearing and deaf/hard-of-hearing elementary students.

    Science.gov (United States)

    Al-Hilawani, Y A

    2000-09-01

    The purpose of this study was to examine the influence of using the Cognitive Behaviour Modification (CBM) technique on the subtraction skills of third grade hearing and deaf/hard-of-hearing students. The results indicated that the CBM deaf/hard-of-hearing students and the CBM and non-CBM hearing students made more progress in solving the subtraction problems than the non-CBM deaf/hard-of-hearing students. The results also showed that there were no significant differences between the CBM deaf/hard-of-hearing and the non-CBM hearing students; and there were no significant differences between the CBM and non-CBM hearing students. The results revealed that the CBM hearing students achieved significantly higher post-test scores than the CBM deaf/hard-of-hearing students. However, the CBM deaf/hard-of-hearing students obtained a significantly higher gain score compared to the CBM and non-CBM hearing students. Implications for teachers and suggestions for future research are discussed in this paper.

  10. Subtracted geometry

    Science.gov (United States)

    Saleem, Zain Hamid

    In this thesis we study a special class of black hole geometries called subtracted geometries. Subtracted geometry black holes are obtained when one omits certain terms from the warp factor of the metric of general charged rotating black holes. The omission of these terms allows one to write the wave equation of the black hole in a completely separable way and one can explicitly see that the wave equation of a massless scalar field in this slightly altered background of a general multi-charged rotating black hole acquires an SL(2, R) x SL(2, R) x SO(3) symmetry. The "subtracted limit" is considered an appropriate limit for studying the internal structure of the non-subtracted black holes because new 'subtracted' black holes have the same horizon area and periodicity of the angular and time coordinates in the near horizon regions as the original black hole geometry it was constructed from. The new geometry is asymptotically conical and is physically similar to that of a black hole in an asymptotically confining box. We use the different nice properties of these geometries to understand various classically and quantum mechanically important features of general charged rotating black holes.

  11. Reducing magnetic zero drift by optimizing proportions of neon dual isotopes in laser gyros

    Institute of Scientific and Technical Information of China (English)

    DI Nan; ZHAO Jian-lin

    2012-01-01

    The relationships among the proportions of the neon dual isotopes ratio,scale factor corrections (SFCs),light intensities,environmental magnetic field and magnetic zero drift are discussed in detail by numerical simulations.The results show that the unification of the optimal operating point (OP) and the frequency stabilization operating point (FSP) is achievable by adjusting the proportions of neon dual isotopes accurately and tuning the cavity length with frequency stabilization system exactly.In that case,the left-rotation and right-rotation gyros can obtain the same SFC,which can decrease the magnetic sensitivity of the laser gyro efficiently.The Zeeman effect zero drift and the Faraday bias zero drift are both reduced by two orders of magnitude,while the magnetic shielding requirement of laser tube is decreased by 1-2 orders of magnitude.

  12. Behavior Subtraction

    CERN Document Server

    Jodoin, P M; Konrad, J

    2009-01-01

    Background subtraction has been a driving engine for many computer vision and video analytics tasks. Although its many variants exist, they all share the underlying assumption that photometric scene properties are either static or exhibit temporal stationarity. While this works in some applications, the model fails when one is interested in discovering {\\it changes in scene dynamics} rather than those in a static background; detection of unusual pedestrian and motor traffic patterns is but one example. We propose a new model and computational framework that address this failure by considering stationary scene dynamics as a ``background'' with which observed scene dynamics are compared. Central to our approach is the concept of an {\\it event}, that we define as short-term scene dynamics captured over a time window at a specific spatial location in the camera field of view. We compute events by time-aggregating motion labels, obtained by background subtraction, as well as object descriptors (e.g., object size)....

  13. Effect of injection technique on temporal parametric imaging derived from digital subtraction angiography in patient specific phantoms

    Science.gov (United States)

    Ionita, Ciprian N.; Garcia, Victor L.; Bednarek, Daniel R.; Snyder, Kenneth V.; Siddiqui, Adnan H.; Levy, Elad I.; Rudin, Stephen

    2014-03-01

    Parametric imaging maps (PIM's) derived from digital subtraction angiography (DSA) for the cerebral arterial flow assessment in clinical settings have been proposed, but experiments have yet to determine the reliability of such studies. For this study, we have observed the effects of different injection techniques on PIM's. A flow circuit set to physiologic conditions was created using an internal carotid artery phantom. PIM's were derived for two catheter positions, two different contrast bolus injection volumes (5ml and 10 ml), and four injection rates (5, 10, 15 and 20 ml/s). Using a gamma variate fitting approach, we derived PIM's for mean-transit-time (MTT), time-to-peak (TTP) and bolus-arrivaltime (BAT). For the same injection rates, a larger bolus resulted in an increased MTT and TTP, while a faster injection rate resulted in a shorter MTT, TTP, and BAT. In addition, the position of the catheter tip within the vasculature directly affected the PIM. The experiment showed that the PIM is strongly correlated with the injection conditions, and, therefore, they have to be interpreted with caution. PIM images must be taken from the same patient to be able to be meaningfully compared. These comparisons can include pre- and post-treatment images taken immediately before and after an interventional procedure or simultaneous arterial flow comparisons through the left and right cerebral hemispheres. Due to the strong correlation between PIM and injection conditions, this study indicates that this assessment method should be used only to compare flow changes before and after treatment within the same patient using the same injection conditions.

  14. Fabrication of Thermoelectric Devices Using Additive-Subtractive Manufacturing Techniques: Application to Waste-Heat Energy Harvesting

    Science.gov (United States)

    Tewolde, Mahder

    Thermoelectric generators (TEGs) are solid-state devices that convert heat directly into electricity. They are well suited for waste-heat energy harvesting applications as opposed to primary energy generation. Commercially available thermoelectric modules are flat, inflexible and have limited sizes available. State-of-art manufacturing of TEG devices relies on assembling prefabricated parts with soldering, epoxy bonding, and mechanical clamping. Furthermore, efforts to incorporate them onto curved surfaces such as exhaust pipes, pump housings, steam lines, mixing containers, reaction chambers, etc. require custom-built heat exchangers. This is costly and labor-intensive, in addition to presenting challenges in terms of space, thermal coupling, added weight and long-term reliability. Additive manufacturing technologies are beginning to address many of these issues by reducing part count in complex designs and the elimination of sub-assembly requirements. This work investigates the feasibility of utilizing such novel manufacturing routes for improving the manufacturing process of thermoelectric devices. Much of the research in thermoelectricity is primarily focused on improving thermoelectric material properties by developing of novel materials or finding ways to improve existing ones. Secondary to material development is improving the manufacturing process of TEGs to provide significant cost benefits. To improve the device fabrication process, this work explores additive manufacturing technologies to provide an integrated and scalable approach for TE device manufacturing directly onto engineering component surfaces. Additive manufacturing techniques like thermal spray and ink-dispenser printing are developed with the aim of improving the manufacturing process of TEGs. Subtractive manufacturing techniques like laser micromachining are also studied in detail. This includes the laser processing parameters for cutting the thermal spray materials efficiently by

  15. Behavior subtraction.

    Science.gov (United States)

    Jodoin, Pierre-Marc; Saligrama, Venkatesh; Konrad, Janusz

    2012-09-01

    Background subtraction has been a driving engine for many computer vision and video analytics tasks. Although its many variants exist, they all share the underlying assumption that photometric scene properties are either static or exhibit temporal stationarity. While this works in many applications, the model fails when one is interested in discovering changes in scene dynamics instead of changes in scene's photometric properties; the detection of unusual pedestrian or motor traffic patterns are but two examples. We propose a new model and computational framework that assume the dynamics of a scene, not its photometry, to be stationary, i.e., a dynamic background serves as the reference for the dynamics of an observed scene. Central to our approach is the concept of an event, which we define as short-term scene dynamics captured over a time window at a specific spatial location in the camera field of view. Unlike in our earlier work, we compute events by time-aggregating vector object descriptors that can combine multiple features, such as object size, direction of movement, speed, etc. We characterize events probabilistically, but use low-memory, low-complexity surrogates in a practical implementation. Using these surrogates amounts to behavior subtraction, a new algorithm for effective and efficient temporal anomaly detection and localization. Behavior subtraction is resilient to spurious background motion, such as due to camera jitter, and is content-blind, i.e., it works equally well on humans, cars, animals, and other objects in both uncluttered and highly cluttered scenes. Clearly, treating video as a collection of events rather than colored pixels opens new possibilities for video analytics.

  16. Where does streamwater come from in low relief forested watersheds? A dual isotope approach

    Directory of Open Access Journals (Sweden)

    J. Klaus

    2014-03-01

    Full Text Available The time- and geographic sources of streamwater in low relief watersheds are poorly understood. This is partly due to the difficult combination of low runoff coefficients and often damped streamwater isotopic signals precluding traditional hydrograph separation and convolution integral approaches. Here we present a dual isotope approach involving 18O and 2H of water in a low angle forested watershed to determine streamwater source components and then build a conceptual model of streamflow generation. We focus on three headwater lowland sub-catchments draining the Savannah River Site in South Carolina, USA. Our results for a 3 year sampling period show that the slopes of the meteoric water lines/evaporation water lines (MWL/EWL of the catchment water sources can be used to extract information on runoff source in ways not considered before. Our dual isotope approach was able to identify unique hillslope, riparian and deep groundwater, and streamflow compositions. The streams showed strong evaporative enrichment compared to the local meteoric water line (δ2H = 6.45 × δ18O + 6.26‰ with slopes of 2.52, 2.84, and 2.86. Based on the unique and unambiguous slopes of the EWLs of the different water cycle components and the isotopic time series of the individual components, we were able to show how the riparian zone controls baseflow in this system and how the riparian zone "resets" the stable isotope composition of the observed streams in our low angle, forested watersheds. Although this approach is limited in terms of quantifying mixing percentages between different end-members, our dual isotope approach enable extraction of hydrologically useful information in a region with little change in individual isotope time series.

  17. Dual Isotope SPECT Study With Epilepsy Patients Using Semiconductor SPECT System.

    Science.gov (United States)

    Shiga, Tohru; Suzuki, Atsuro; Sakurai, Kotarou; Kurita, Tsugiko; Takeuchi, Wataru; Toyonaga, Takuya; Hirata, Kenji; Kobashi, Keiji; Katoh, Chietsugu; Kubo, Naoki; Tamaki, Nagara

    2017-09-01

    We developed a prototype CdTe SPECT system with 4-pixel matched collimator for brain study. This system provides high-energy-resolution (6.6%), high-sensitivity (220 cps/MBq/head), and high-spatial-resolution images. The aim of this study was to evaluate dual-isotope study of CBF and central benzodiazepine receptor (BZR) images using Tc-ECD and I-IMZ with the new SPECT system in patients with epilepsy comparing with single-isotope study using the conventional scintillation gamma camera. This study included 13 patients with partial epilepsy. The BZR images were acquired at 3 hours after I-IMZ injection for 20 minutes. The images of IMZ were acquired with a conventional 3-head scintillation gamma camera. After BZR image acquisition with the conventional camera, Tc-ECD was injected, and CBF and BZR images were acquired simultaneously 5 minutes after ECD injection with the new SPECT system. The CBF images were also acquired with the conventional camera on separate days. The findings were visually analyzed, and 3D-SSP maximum Z scores of lesions were compared between the 2 studies. There were 47 abnormal lesions on BZR images and 60 abnormal lesions on CBF images in the single-isotope study with the conventional camera. Dual-isotope study with the new system showed concordant abnormal findings of 46 of 47 lesions on BZR and 54 of 60 lesions on CBF images with the single-isotope study with the conventional camera. There was high agreement between the 2 studies in both BZR and CBF findings (Cohen κ values = 0.96 for BZR and 0.78 for CBF). In semiquantitative analysis, maximum Z scores of dual-isotope study with the new system strongly correlated with those of single-isotope study with the conventional camera (BZR: r = 0.82, P < 0.05, CBF: r = 0.87, P < 0.05). Our new SPECT system permits dual-isotope study for pixel-by-pixel analysis of CBF and BZR information with the same pathophysiological condition in patients with epilepsy.

  18. Suppression subtractive hybridization.

    Science.gov (United States)

    Ghorbel, Mohamed T; Murphy, David

    2011-01-01

    Comparing two RNA populations that differ from the effects of a single independent variable, such as a drug treatment or a specific genetic defect, can establish differences in the abundance of specific transcripts that vary in a population dependent manner. There are different methods for identifying differentially expressed genes. These methods include microarray, Serial Analysis of Gene Expression (SAGE), and quantitative Reverse-Transcriptase Polymerase Chain Reaction (qRT-PCR). Herein, the protocol describes an easy and cost-effective alternative that does not require prior knowledge of the transcriptomes under examination. It is specifically relevant when low levels of RNA starting material are available. This protocol describes the use of Switching Mechanism At RNA Termini Polymerase Chain Reaction (SMART-PCR) to amplify cDNA from small amounts of RNA. The amplified cDNA populations under comparison are then subjected to Suppression Subtractive Hybridization (SSH-PCR). SSH-PCR is a technique that couples subtractive hybridization with suppression PCR to selectively amplify fragments of differentially expressed genes. The resulting products are cDNA populations enriched for significantly overrepresented transcripts in either of the two input RNAs. These cDNA populations can then be cloned to generate subtracted cDNA library. Microarrays made with clones from the subtracted forward and reverse cDNA libraries are then screened for differentially expressed genes using targets generated from tester and driver total RNAs.

  19. Image subtraction by solid state electroradiography

    Energy Technology Data Exchange (ETDEWEB)

    Fallone, B.G.; Podgorsak, E.B. (McGill Univ., Montreal, Quebec (Canada). Dept. of Radiation Oncology; McGill Univ., Montreal, Quebec (Canada). Dept. of Diagnostic Radiology)

    1984-06-01

    An analog radiographic image subtraction technique is presented. A selenium photoconductor is used as the radiation sensitive medium and image subtraction is achieved by electrostatically adding latent images of opposite polarities to get a latent image of the region of interest. In principle, the technique is simple and a comparison with commercial digital techniques shows a similar image quality, suggesting that the electrostatic subtraction technique could be developed into a clinical tool as an inexpensive alternative to digital radiography.

  20. Suppression subtraction hybridization (SSH) and macroarray techniques reveal differential gene expression profiles in brain of sea bream infected with nodavirus.

    Science.gov (United States)

    Dios, S; Poisa-Beiro, L; Figueras, A; Novoa, B

    2007-03-01

    Despite of the impact that viruses have on aquatic organisms, relatively little is known on how fish fight against these infections. In this work, the brain gene expression pattern of sea bream (Sparus aurata) in response to nodavirus infection was investigated. We used the suppression subtractive hybridization (SSH) method to generate a subtracted cDNA library enriched with gene transcripts differentially expressed after 1 day post-infection. Some of the ESTs from the infected tissues fell in gene categories related to stress and immune responses. For the reverse library (ESTs expressed in controls compared with infected tissues) the most abundant transcripts were of ribosomal and mitochondrial nature. Several ESTs potentially induced by virus exposure were selected for in vivo expression studies. We observed a clear difference in expression between infected and control samples for two candidate genes, ubiquitin conjugating enzyme 7 interacting protein, which seems to play an important role in apoptosis and the interferon induced protein with helicase C domain 1 (mda-5) that contributes to apoptosis and regulates the type I IFN production, a key molecule of the antiviral innate response in most organisms.

  1. New Noise Subtraction Methods in Lattice QCD

    CERN Document Server

    Baral, Suman; Morgan, Ronald B

    2016-01-01

    Noise subtraction techniques can help reduce the statistical uncertainty in the extraction of hard to detect signals. We describe new noise subtraction methods in Lattice QCD which apply to disconnected diagram evaluations. Some of the noise suppression techniques include polynomial quark matrix methods, eigenspectrum deflation methods, and combination methods. Our most promising technique combines polynomial and Hermitian deflation subtraction methods. The overall goal is to improve the efficiency of Lattice QCD noise method algorithms.

  2. Transactivating effect of complete S protein of hepatitis B virus and cloning of genes transactivated by complete S protein using suppression subtractive hybridization technique

    Institute of Scientific and Technical Information of China (English)

    Gui-Qin Bai; Yan Liu; Jun Cheng; Shu-Lin Zhang; Ya-Fei Yue; Yan-Ping Huang; Li-Ying Zhang

    2005-01-01

    AIM: To investigate the transactivating effect of complete S protein of hepatitis B virus (HBV) and to construct a subtractive cDNA library of genes transactivated by complete S protein of HBV by suppression subtractive hybridization (SSH) technique and to clone genes associated with its transactivation activity, and to pave the way for elucidating the pathogenesis of hepatitis B virus infection.METHODS: pcDNA3.1(-)-complete S containing full-length HBV S gene was constructed by insertion of HBV complete S gene into BarmH-I/Kpn I sites. HepG2 cells were cotransfected with pcDNA3.1(-)-complete S and pSV-lacZ.After 48 h, cells were collected and detected for the expression of β-galactosidase (β-gal). Suppression subtractive hybridization and bioinformatics techniques were used.The mRNA of HepG2 cells transfected with pcDNA3.1(-)-complete S and pcDNA3.1(-) empty vector was isolated,and detected for the expression of complete S protein by reverse transcription polymerase chain reaction (RT-PCR)method, and cDNA was synthesized. After digestion with restriction enzyme RcaI, cDNA fragments were obtained.Tester cDNA was then divided into two groups and ligated to the specific adaptors 1 and 2, respectively. After tester cDNA had been hybridized with driver cDNA twice and underwent nested PCR twice, amplified cDNA fragments were subcloned into pGEM-Teasy vectors to set up the subtractive library. Amplification of the library was carried out within E. coli strain DH5α. The cDNA was sequenced and analyzed in GenBank with BLAST search after polymerase chain reaction (PCR) amplification.RESULTS: The complete S mRNA could be detected by RT-PCR in HepG2 cells transfected with the pcDNA3.1(-)-complete S. The activity of β-gal in HepG2 cells transfected with the pcDNA3.1(-)-complete S was 6.9 times higher than that of control plasmid. The subtractive library of genes transactivated by HBV complete S protein was constructed successfully. The amplified library contains 86

  3. Renogram and deconvolution parameters in diagnosis of renal artery stenosis. Variants of background subtraction and analysis techniques

    Energy Technology Data Exchange (ETDEWEB)

    Kempi, V. [Dept. of Clinical Physiology, Sjukhuset, Oestersund (Sweden)

    2007-07-01

    Aim: Multivariate statistical methods can be used for objective analysis. The emphasis is on analysing renal function parameters together, not one at a time. The aim is to identify curve parameters useful in making predictions in kidneys with and without renal artery stenosis (RAS). Patients, methods: 68 patients with resistant hypertension were subjected to captopril renography with {sup 99m}Tc-DTPA. Variants of background areas and background subtraction methods were employed. A correction was applied for loss of renal parenchyma. Parameters from time-activity curves and retention curves from deconvolution were calculated. Renal angiography established the presence or absence of RAS. Logistic regression analysis, using age- and kidney size-adjusted models, was performed to assess the capability of renography and deconvolution to differentiate between kidneys with and without RAS. Results: Discrimination between normal kidneys and RAS was achieved by deconvolution and by renography. Deconvolution was the method of first rank with a sensitivity of 87% and a specificity of 98%. For separation of RAS and kidneys with parenchymal insufficiency deconvolution was the method of first rank with a sensitivity of 80% and specificity of 89%, whereas renography produced poor results. Conclusion: The best performance with {sup 99m}Tc-DTPA was based on normalised background subtraction using a rectangular area between the kidneys. Deconvolution produced the most favourable results in the separation of kidneys with and without RAS. For separation of RAS and kidneys with parenchymal insufficiency conventional renography produced poor results. Conceptually, the results of a logistic regression analysis of renal function parameters may raise possibilities in the field of computer-aided diagnosis. (orig.)

  4. Fate and Transport of Nitrate in an Alpine Catchment Based on Dual-Isotopic and End-Member Mixing Analysis

    Science.gov (United States)

    Williams, M. W.; Liu, F.; Kendall, C.

    2003-12-01

    Attempts to understand nitrate loss from small watersheds have been the focus of much research. In general, these results have shown that understanding how sources and flowpaths of nitrate-rich waters change with time necessitates a combination of isotopic, chemical, and hydrometric data. New and evolving tools to understand the fate and transport of nitrate include dual-isotopic analysis of both the nitrogen and oxygen atoms in the nitrate molecule, and end-member mixing analysis (EMMA). However, to-date no one has combined these two approaches. Here we present results from both dual-isotope analysis and EMMA to understand the fate and transport of nitrate in the high-elevation Green Lakes watershed of the Colorado Front Range. Thirty-five samples were collected and analyzed for the dual isotopes of nitrate, and showed that values of δ 18O in atmospheric deposition had considerable overlap with values in stream waters. There was a strong counterclockwise pattern of hysteresis when δ 18O is plotted versus stream discharge, consistent with a mixture of atmospheric and microbial nitrate sources on the rising limb of the hydrograph, then mostly a microbial source on the recession limb of the hydrograph. A chemograph of nitrate sources developed using EMMA shows atmospheric deposition the predominant source at the initiation of snowmelt runoff, with soil water and talus becoming the dominant source at peak runoff, and talus-water and baseflow both important on the recession limb of the hydrograph. We were able to qualitatively evaluate the EMMA results by developing a 2-component nitrate source model using the dual-isotope values. The dual-isotope mixing model agreed well with the atmospheric and subsurface sources of nitrate identified using EMMA.

  5. Individual-specific transgenerational marking of fish populations based on a barium dual-isotope procedure.

    Science.gov (United States)

    Huelga-Suarez, Gonzalo; Moldovan, Mariella; Garcia-Valiente, America; Garcia-Vazquez, Eva; Alonso, J Ignacio Garcia

    2012-01-01

    The present study focuses on the development and evaluation of an individual-specific transgenerational marking procedure using two enriched barium isotopes, (135)Ba and (137)Ba, mixed at a given and selectable molar ratio. The method is based on the deconvolution of the isotope patterns found in the sample into four molar contribution factors: natural xenon (Xe nat), natural barium (Ba nat), Ba135, and Ba137. The ratio of molar contributions between Ba137 and Ba135 is constant and independent of the contribution of natural barium in the sample. This procedure was tested in brown trout ( Salmo trutta ) kept in captivity. Trout were injected with three different Ba137/Ba135 isotopic signatures ca. 7 months and 7 days before spawning to compare the efficiency of the marking procedure at long and short term, respectively. The barium isotopic profiles were measured in the offspring by means of inductively coupled plasma mass spectrometry. Each of the three different isotopic signatures was unequivocally identified in the offspring in both whole eggs and larvae. For 9 month old offspring, the characteristic barium isotope signatures could also be detected in the otoliths even in the presence of a high and variable amount of barium of natural isotope abundance. In conclusion, it can be stated that the proposed dual-isotope marking is inheritable and can be detected after both long-term and short-term marking. Furthermore, the dual-isotope marking can be made individual-specific, so that it allows identification of offspring from a single individual or a group of individuals within a given fish group.

  6. Using a dual isotopic approach to trace sources and mixing of sulphate in Changjiang Estuary, China

    Energy Technology Data Exchange (ETDEWEB)

    Li Siliang, E-mail: lisiliang@vip.skleg.cn [State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002 (China); Liu Congqiang; Patra, Sivaji [State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002 (China); Wang Fushun [Institute of Applied Radiation, School of Environmental and Chemical Engineering, Shanghai University, Shanghai 201800 (China); Wang Baoli; Yue Fujun [State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002 (China)

    2011-06-15

    Highlights: > Changjiang Estuary plays an important role in transportation of the water and solute. > The dual isotopic method could be used to understand sulfate biogeochemistry in estuaries. > Mixing processes should be a major factor involved in the distribution of water and sulphate. > Sulphate in the Changjiang River mainly derived from atmospheric deposition, evaporite dissolution and sulphide oxidation. - Abstract: The dual isotopic compositions of dissolved SO{sub 4}{sup 2-} in aquatic systems are commonly used to ascertain SO{sub 4}{sup 2-} sources and possible biogeochemical processes. In this study, the physical parameters, major anions and isotopic compositions of SO{sub 4}{sup 2-} in water samples from Changjiang River (Nanjin) to the East Sea in Changjiang Estuary were determined. The salinity ranged from 0 per mille to 32.3 per mille in the estuary water samples. The Cl{sup -},SO{sub 4}{sup 2-} concentrations and {delta}{sup 18}O-H{sub 2}O values followed the salinity variations from freshwater to seawater, which indicated that mixing processes might be a major factor involved in the distribution of water and solutes. The contents and isotopic compositions of SO{sub 4}{sup 2-} suggested that atmospheric deposition, evaporite dissolution and sulphide oxidation were the major sources of dissolved SO{sub 4}{sup 2-} in the freshwater of Changjiang River. In addition, the mixing model calculated by contents and isotopic compositions of SO{sub 4}{sup 2-} indicated that the mixing of freshwater and sea water was the major factor involved in SO{sub 4}{sup 2-} distribution in Changjiang Estuary. However, slightly elevated {delta}{sup 18}O-SO{sub 4} values were observed in the turbidity maximum zone, which suggested that biological processes might affect the O isotopic compositions of SO{sub 4}{sup 2-} there.

  7. Digital subtraction laryngography

    Energy Technology Data Exchange (ETDEWEB)

    Brown, B.W.; Enzmann, D.R.; Hopp, M.L.; Castellino, R.A.

    1983-06-01

    Digital subtraction laryngography was used to evaluate laryngeal function in 8 patients: 4 with normal larynxes and 4 with laryngeal disease. Subtracted digital images provided a dynamic display of the extent and symmetry of vocal cord excursions and pyriform sinus inflation, and the vocal cord resting position was also clearly depicted. The technical details of digital subtraction laryngography and its application are described.

  8. Bone infection in patients suspected of complicating osteomyelitis: the diagnostic value of dual isotope bone-granulocyte scintigraphy

    DEFF Research Database (Denmark)

    Buhl, Thora; Stentzer, Kim; Hede, Adam;

    2005-01-01

    AIM: The purpose of this study was to evaluate the diagnostic value of dual isotope bone-granulocyte scintigraphy in patients with known bone pathology clinically suspected of osteomyelitis, i.e. complicating osteomyelitis, using per-operative bacterial culture from bone as reference. METHODS...... interpreted as positive for osteomyelitis if regions of interests of pathologic 111In granulocyte accumulation included 99mTc MDP activity on the bone images (except in the spine). RESULTS: The sensitivity, specificity, and accuracy were 84, 71 and 79%, respectively, for simultaneous, dual isotope bone......-granulocyte scintigraphy, higher than the other diagnostic parameters. CONCLUSION: Simultaneous bone-granulocyte scintigraphy is a valuable diagnostic tool in diagnosing osteomyelitis complicating other bone pathology with or without soft-tissue infection....

  9. Regularized image reconstruction algorithms for dual-isotope myocardial perfusion SPECT (MPS) imaging using a cross-tracer prior.

    Science.gov (United States)

    He, Xin; Cheng, Lishui; Fessler, Jeffrey A; Frey, Eric C

    2011-06-01

    In simultaneous dual-isotope myocardial perfusion SPECT (MPS) imaging, data are simultaneously acquired to determine the distributions of two radioactive isotopes. The goal of this work was to develop penalized maximum likelihood (PML) algorithms for a novel cross-tracer prior that exploits the fact that the two images reconstructed from simultaneous dual-isotope MPS projection data are perfectly registered in space. We first formulated the simultaneous dual-isotope MPS reconstruction problem as a joint estimation problem. A cross-tracer prior that couples voxel values on both images was then proposed. We developed an iterative algorithm to reconstruct the MPS images that converges to the maximum a posteriori solution for this prior based on separable surrogate functions. To accelerate the convergence, we developed a fast algorithm for the cross-tracer prior based on the complete data OS-EM (COSEM) framework. The proposed algorithm was compared qualitatively and quantitatively to a single-tracer version of the prior that did not include the cross-tracer term. Quantitative evaluations included comparisons of mean and standard deviation images as well as assessment of image fidelity using the mean square error. We also evaluated the cross tracer prior using a three-class observer study with respect to the three-class MPS diagnostic task, i.e., classifying patients as having either no defect, reversible defect, or fixed defects. For this study, a comparison with conventional ordered subsets-expectation maximization (OS-EM) reconstruction with postfiltering was performed. The comparisons to the single-tracer prior demonstrated similar resolution for areas of the image with large intensity changes and reduced noise in uniform regions. The cross-tracer prior was also superior to the single-tracer version in terms of restoring image fidelity. Results of the three-class observer study showed that the proposed cross-tracer prior and the convergent algorithms improved the

  10. Dual-isotope single-photon emission computed tomography for dopamine and serotonin transporters in normal and parkinsonian monkey brains

    Energy Technology Data Exchange (ETDEWEB)

    Li, I-H. [Graduate Institute of Medical Sciences, National Defense Medical Center, Taipei 114, Taiwan (China); Huang, W.-S. [Department of Nuclear Medicine, Tri-Service General Hospital, Taipei, 114, Taiwan (China); Yeh, C.-B. [Department of Psychiatry, Tri-Service General Hospital, Taipei, 114, Taiwan (China); Liao, M.-H.; Chen, C.-C.; Shen, L.-H. [Division of Isotope Application, Institute of Nuclear Energy Research, Taoyaun, 325 Taiwan (China); Liu, J.-C. [Department of Biology and Anatomy, National Defense Medical Center, Taipei 114, Taiwan (China); Ma, K.-H. [Department of Biology and Anatomy, National Defense Medical Center, Taipei 114, Taiwan (China)], E-mail: kuohsing91@yahoo.com.tw

    2009-08-15

    Introduction: Parkinson's disease (PD) affects both dopaminergic and serotonergic systems. In this study, we simultaneously evaluated dopamine and serotonin transporters in primates using dual-isotope single-photon emission computed tomography (SPECT) imaging and compared the results with traditional single-isotope imaging. Methods: Four healthy and one 6-OHDA-induced PD monkeys were used for this study. SPECT was performed over 4 h after individual or simultaneous injection of [{sup 99m}Tc]TRODAT-1 (a dopamine transporter imaging agent) and [{sup 123}I]ADAM (a serotonin transporter imaging agent). Results: The results showed that the image quality and uptake ratios in different brain regions were comparable between single- and dual-isotope studies. The striatal [{sup 99m}Tc]TRODAT-1 uptake in the PD monkey was markedly lower than that in normal monkeys. The uptake of [{sup 123}I]ADAM in the midbrain of the PD monkey was comparable to that in the normal monkeys, but there were decreased uptakes in the thalamus and striatum of the PD monkey. Conclusions: Our results suggest that dual-isotope SPECT using [{sup 99m}Tc]TRODAT-1 and [{sup 123}I]ADAM can simultaneously evaluate changes in dopaminergic and serotonergic systems in a PD model.

  11. Optimising Optimal Image Subtraction

    CERN Document Server

    Israel, H; Schuh, S; Israel, Holger; Hessman, Frederic V.; Schuh, Sonja

    2006-01-01

    Difference imaging is a technique for obtaining precise relative photometry of variable sources in crowded stellar fields and, as such, constitutes a crucial part of the data reduction pipeline in surveys for microlensing events or transiting extrasolar planets. The Optimal Image Subtraction (OIS) algorithm permits the accurate differencing of images by determining convolution kernels which, when applied to reference images of particularly good quality, provide excellent matches to the point-spread functions (PSF) in other images of the time series to be analysed. The convolution kernels are built as linear combinations of a set of basis functions, conventionally bivariate Gaussians modulated by polynomials. The kernel parameters must be supplied by the user and should ideally be matched to the PSF, pixel-sampling, and S/N of the data to be analysed. We have studied the outcome of the reduction as a function of the kernel parameters using our implementation of OIS within the TRIPP package. From the analysis o...

  12. Pulse subtraction Doppler

    Science.gov (United States)

    Mahue, Veronique; Mari, Jean Martial; Eckersley, Robert J.; Caro, Colin G.; Tang, Meng-Xing

    2010-01-01

    Recent advances have demonstrated the feasibility of molecular imaging using targeted microbubbles and ultrasound. One technical challenge is to selectively detect attached bubbles from those freely flowing bubbles and surrounding tissue. Pulse Inversion Doppler is an imaging technique enabling the selective detection of both static and moving ultrasound contrast agents: linear scatterers generate a single band Doppler spectrum, while non-linear scatterers generate a double band spectrum, one being uniquely correlated with the presence of contrast agents and non-linear tissue signals. We demonstrate that similar spectrums, and thus the same discrimination, can be obtained through a Doppler implementation of Pulse Subtraction. This is achieved by reconstructing a virtual echo using the echo generated from a short pulse transmission. Moreover by subtracting from this virtual echo the one generated from a longer pulse transmission, it is possible to fully suppress the echo from linear scatterers, while for non-linear scatterers, a signal will remain, allowing classical agent detection. Simulations of a single moving microbubble and a moving linear scatterer subject to these pulses show that when the virtual echo and the long pulse echo are used to perform pulsed Doppler, the power Doppler spectrum allows separation of linear and non-linear moving scattering. Similar results are obtained on experimental data acquired on a flow containing either microbubble contrast agents or linear blood mimicking fluid. This new Doppler method constitutes an alternative to Pulse Inversion Doppler and preliminary results suggest that similar dual band spectrums could be obtained by the combination of any non-linear detection technique with Doppler demodulation.

  13. Non-contrast-enhanced MR angiography in critical limb ischemia: performance of quiescent-interval single-shot (QISS) and TSE-based subtraction techniques

    Energy Technology Data Exchange (ETDEWEB)

    Altaha, Mustafa A. [University Health Network, Department of Medical Imaging, Peter Munk Cardiac Centre, Toronto, Ontario (Canada); Jaskolka, Jeffrey D.; Tan, Kongteng; Menezes, Ravi J. [University Health Network, Department of Medical Imaging, Peter Munk Cardiac Centre, Toronto, Ontario (Canada); University of Toronto, Department of Medical Imaging, Toronto, Ontario (Canada); Rick, Manuela; Schmitt, Peter [Siemens Healthcare, Erlangen (Germany); Wintersperger, Bernd J. [University Health Network, Department of Medical Imaging, Peter Munk Cardiac Centre, Toronto, Ontario (Canada); University of Toronto, Department of Medical Imaging, Toronto, Ontario (Canada); Toronto General Hospital, Department of Medical Imaging, Toronto, Ontario (Canada)

    2017-03-15

    The aim of this study was to evaluate diagnostic performance of non-contrast-enhanced 2D quiescent-interval single-shot (QISS) and 3D turbo spin-echo (TSE)-based subtraction magnetic resonance angiography (MRA) in the assessment of peripheral arteries in patients with critical limb ischemia (CLI). Nineteen consecutive patients (74 % male, 72.8 ± 9.9 years) with CLI underwent 2D QISS and 3D TSE-based subtraction MRA at 1.5 T. Axial-overlapping QISS MRA (3 mm/2 mm; 1 x 1 mm{sup 2}) covered from the toes to the aortic bifurcation while coronal 3D TSE-based subtraction MRA (1.3 x 1.2 x 1.3 mm{sup 3}) was restricted to the calf only. MRA data sets (two readers) were evaluated for stenosis (≥50 %) and image quality. Results were compared with digital subtraction angiography (DSA). Two hundred and sixty-seven (267) segments were available for MRA-DSA comparison, with a prevalence of stenosis ≥50 % of 41.9 %. QISS MRA was rated as good to excellent in 79.5-96.0 % of segments without any nondiagnostic segments; 89.8-96.1 % of segments in 3D TSE-based subtraction MRA were rated as nondiagnostic or poor. QISS MRA sensitivities and specificities (segmental) were 92 % and 95 %, respectively, for reader one and 81-97 % for reader two. Due to poor image quality of 3D TSE-based subtraction MRA, diagnostic performance measures were not calculated. QISS MRA demonstrates excellent diagnostic performance and higher robustness than 3D TSE-based subtraction MRA in the challenging patient population with CLI. (orig.)

  14. Nitrate dual isotopic composition in the northern South China Sea and neighboring West Philippine Sea

    Science.gov (United States)

    Yang, J.; Xu, M.; Wu, Y.; Dai, M.; Kao, S.

    2013-12-01

    Nitrate nitrogen and oxygen isotopic compositions (δ15NNO3 and δ18ONO3) were used to diagnose nitrate dynamics and the origins of water masses in the northern South China Sea (SCS) and West Philippine Sea (WPS) where water exchanges via the Luzon Strait at different depths. In the SCS, 1-3‰ greater upward increase in δ18ONO3 relative to corresponding δ15NNO3 was just observed in the lower euphotic zone (EZ), indicating a rapid internal cycle of nitrate assimilation and remineralization. Much lower nitrate concentration in the EZ of WPS does not allow us to measure its dual isotopes. From 500 m deep to the base of EZ in the WPS, non-proportional decreases in δ15NNO3 (from 6.4‰ to 2.1-2.6‰) and δ18ONO3 (from 3.0‰ to 1.1‰) accompanying with elevated N:P ratio anomalies (N* from -1.2 μM up to 2 μM), suggest the accumulation of atmospheric-derived N (e.g. N2 fixation and/or N deposition). This allochthonous N signal cumulated in the subsurface of WPS may regulate the δ15NNO3 in the SCS subsurface due to seasonal Kuroshio intrusion, which could supply isotopically light nitrate as newly fixed N source to the SCS. The higher (~0.5‰) δ15NNO3 and δ18ONO3 values, associated with lower N* were detected in the WPS intermediate water (WPS-IW, σθ = 26.5~27.1 kg m-3) around depth of 600-800 m (especially at a southern site) when compared to those of the conventional water source coming from North Pacific Intermediate Water (NPIW). By combining nitrate concentration, N* and δ15NNO3 as constraints, we propose that an additional southerly source other than NPIW may feed into the WPS-IW. On the other hand, the SCS intermediate water (SCS-IW, ~400-700 m), which supposedly sourced from WPS-IW along similar isopycnal levels, showed ~1‰ lower δ15NNO3 and δ18ONO3 values. This reduction in nitrate duel isotopes indicates intense diapycnal mixing primarily due to basin-wide upwelling in the SCS interior. This is the first hand data in the SCS for deep profiles

  15. Optimization and comparison of simultaneous and separate acquisition protocols for dual isotope myocardial perfusion SPECT

    Science.gov (United States)

    Ghaly, Michael; Links, Jonathan M.; Frey, Eric C.

    2015-07-01

    Dual-isotope simultaneous-acquisition (DISA) rest-stress myocardial perfusion SPECT (MPS) protocols offer a number of advantages over separate acquisition. However, crosstalk contamination due to scatter in the patient and interactions in the collimator degrade image quality. Compensation can reduce the effects of crosstalk, but does not entirely eliminate image degradations. Optimizing acquisition parameters could further reduce the impact of crosstalk. In this paper we investigate the optimization of the rest Tl-201 energy window width and relative injected activities using the ideal observer (IO), a realistic digital phantom population and Monte Carlo (MC) simulated Tc-99m and Tl-201 projections as a means to improve image quality. We compared performance on a perfusion defect detection task for Tl-201 acquisition energy window widths varying from 4 to 40 keV centered at 72 keV for a camera with a 9% energy resolution. We also investigated 7 different relative injected activities, defined as the ratio of Tc-99m and Tl-201 activities, while keeping the total effective dose constant at 13.5 mSv. For each energy window and relative injected activity, we computed the IO test statistics using a Markov chain Monte Carlo (MCMC) method for an ensemble of 1,620 triplets of fixed and reversible defect-present, and defect-absent noisy images modeling realistic background variations. The volume under the 3-class receiver operating characteristic (ROC) surface (VUS) was estimated and served as the figure of merit. For simultaneous acquisition, the IO suggested that relative Tc-to-Tl injected activity ratios of 2.6-5 and acquisition energy window widths of 16-22% were optimal. For separate acquisition, we observed a broad range of optimal relative injected activities from 2.6 to 12.1 and acquisition energy window of widths 16-22%. A negative correlation between Tl-201 injected activity and the width of the Tl-201 energy window was observed in these ranges. The results

  16. Sources and transformations of nitrate from streams draining varying land uses: Evidence from dual isotope analysis

    Science.gov (United States)

    Burns, Douglas A.; Boyer, E.W.; Elliott, E.M.; Kendall, C.

    2009-01-01

    Knowledge of key sources and biogeochemical processes that affect the transport of nitrate (NO3-) in streams can inform watershed management strategies for controlling downstream eutrophication. We applied dual isotope analysis of NO3- to determine the dominant sources and processes that affect NO3- concentrations in six stream/river watersheds of different land uses. Samples were collected monthly at a range of flow conditions for 15 mo during 2004-05 and analyzed for NO3- concentrations, ?? 15NNO3, and ??18ONO3. Samples from two forested watersheds indicated that NO3- derived from nitrification was dominant at baseflow. A watershed dominated by suburban land use had three ??18ONO3 values greater than +25???, indicating a large direct contribution of atmospheric NO 3- transported to the stream during some high flows. Two watersheds with large proportions of agricultural land use had many ??15NNO3 values greater than +9???, suggesting an animal waste source consistent with regional dairy farming practices. These data showed a linear seasonal pattern with a ??18O NO3:??15NNO3 of 1:2, consistent with seasonally varying denitrification that peaked in late summer to early fall with the warmest temperatures and lowest annual streamflow. The large range of ?? 15NNO3 values (10???) indicates that NO 3- supply was likely not limiting the rate of denitrification, consistent with ground water and/or in-stream denitrification. Mixing of two or more distinct sources may have affected the seasonal isotope patterns observed in these two agricultural streams. In a mixed land use watershed of large drainage area, none of the source and process patterns observed in the small streams were evident. These results emphasize that observations at watersheds of a few to a few hundred km2 may be necessary to adequately quantify the relative roles of various NO 3- transport and process patterns that contribute to streamflow in large basins. Copyright ?? 2009 by the American Society of

  17. Non-contrast-enhanced MR angiography in critical limb ischemia: performance of quiescent-interval single-shot (QISS) and TSE-based subtraction techniques.

    Science.gov (United States)

    Altaha, Mustafa A; Jaskolka, Jeffrey D; Tan, Kongteng; Rick, Manuela; Schmitt, Peter; Menezes, Ravi J; Wintersperger, Bernd J

    2017-03-01

    The aim of this study was to evaluate diagnostic performance of non-contrast-enhanced 2D quiescent-interval single-shot (QISS) and 3D turbo spin-echo (TSE)-based subtraction magnetic resonance angiography (MRA) in the assessment of peripheral arteries in patients with critical limb ischemia (CLI). Nineteen consecutive patients (74 % male, 72.8 ± 9.9 years) with CLI underwent 2D QISS and 3D TSE-based subtraction MRA at 1.5 T. Axial-overlapping QISS MRA (3 mm/2 mm; 1 × 1 mm(2)) covered from the toes to the aortic bifurcation while coronal 3D TSE-based subtraction MRA (1.3 × 1.2 × 1.3 mm(3)) was restricted to the calf only. MRA data sets (two readers) were evaluated for stenosis (≥50 %) and image quality. Results were compared with digital subtraction angiography (DSA). Two hundred and sixty-seven (267) segments were available for MRA-DSA comparison, with a prevalence of stenosis ≥50 % of 41.9 %. QISS MRA was rated as good to excellent in 79.5-96.0 % of segments without any nondiagnostic segments; 89.8-96.1 % of segments in 3D TSE-based subtraction MRA were rated as nondiagnostic or poor. QISS MRA sensitivities and specificities (segmental) were 92 % and 95 %, respectively, for reader one and 81-97 % for reader two. Due to poor image quality of 3D TSE-based subtraction MRA, diagnostic performance measures were not calculated. QISS MRA demonstrates excellent diagnostic performance and higher robustness than 3D TSE-based subtraction MRA in the challenging patient population with CLI. • QISS MRA allows reliable diagnosis of peripheral artery stenosis in critical limb ischemia. • Robustness of TSE-based subtraction MRA is limited in critical limb ischemia. • QISS MRA allows robust therapy planning in PAD patients with resting leg pain.

  18. Optimisation of Simultaneous Tl-201/Tc-99m Dual Isotope Reconstruction with Monte-Carlo-Based Scatter Correction

    Directory of Open Access Journals (Sweden)

    Tuija Kangasmaa

    2012-01-01

    Full Text Available Simultaneous Tl-201/Tc-99m dual isotope myocardial perfusion SPECT is seriously hampered by down-scatter from Tc-99m into the Tl-201 energy window. This paper presents and optimises the ordered-subsets-expectation-maximisation-(OS-EM- based reconstruction algorithm, which corrects the down-scatter using an efficient Monte Carlo (MC simulator. The algorithm starts by first reconstructing the Tc-99m image with attenuation, collimator response, and MC-based scatter correction. The reconstructed Tc-99m image is then used as an input for an efficient MC-based down-scatter simulation of Tc-99m photons into the Tl-201 window. This down-scatter estimate is finally used in the Tl-201 reconstruction to correct the crosstalk between the two isotopes. The mathematical 4D NCAT phantom and physical cardiac phantoms were used to optimise the number of OS-EM iterations where the scatter estimate is updated and the number of MC simulated photons. The results showed that two scatter update iterations and 105 simulated photons are enough for the Tc-99m and Tl-201 reconstructions, whereas 106 simulated photons are needed to generate good quality down-scatter estimates. With these parameters, the entire Tl-201/Tc-99m dual isotope reconstruction can be accomplished in less than 3 minutes.

  19. Reliability of the dual-isotope Schilling test for the diagnosis of pernicious anemia or malabsorption syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Domstad, P.A.; Choy, Y.C.; Kim, E.E.; DeLand, F.H.

    1981-05-01

    To evaluate the dual-isotope Schilling test for the diagnosis of pernicious anemia or malabsorption syndrome, 65 studies were selected for clinical correlation. Criteria for pernicious anemia included mean corpuscular volume greater than 100 cu micrometer, serum B12 greater than 100 ng/l, megaloblastic marrow, achlorhydria, reticulocytes greater than 5% on B12 therapy, atrophic gastritis, and elevated serum antibodies to parietal cells or intrinsic factor. Criteria for malabsorption syndrome included: decreased serum B12, folate, and carotene; increased fecal fat; abnormal D-xylose absorption; abnormal radiographic and biopsy findings. /sup 58/Co-cyanocobalamin and /sup 57/Co-cyanocobalamin bound to intrinsic factor were given orally to fasting patients; 1 mg of nonradioactive B12 was injected intramuscularly within two hours. Aliquots of 24-hour urine samples were counted. If the excretion of /sup 58/Co was less than 7% and the /sup 57/Co//sup 58/Co ratio was greater than 1.7, the test indicated pernicious anemia; a ratio less than 1.7 indicated malabsorption syndrome. Sensitivity, specificity, and accuracy of the dual-isotope Schilling test were 83%, 98%, and 94% for pernicious anemia, and 67%, 90%, and 86% for malabsorption syndrome, respectively.

  20. Optimisation of simultaneous tl-201/tc-99m dual isotope reconstruction with monte-carlo-based scatter correction.

    Science.gov (United States)

    Kangasmaa, Tuija; Kuikka, Jyrki; Sohlberg, Antti

    2012-01-01

    Simultaneous Tl-201/Tc-99m dual isotope myocardial perfusion SPECT is seriously hampered by down-scatter from Tc-99m into the Tl-201 energy window. This paper presents and optimises the ordered-subsets-expectation-maximisation-(OS-EM-) based reconstruction algorithm, which corrects the down-scatter using an efficient Monte Carlo (MC) simulator. The algorithm starts by first reconstructing the Tc-99m image with attenuation, collimator response, and MC-based scatter correction. The reconstructed Tc-99m image is then used as an input for an efficient MC-based down-scatter simulation of Tc-99m photons into the Tl-201 window. This down-scatter estimate is finally used in the Tl-201 reconstruction to correct the crosstalk between the two isotopes. The mathematical 4D NCAT phantom and physical cardiac phantoms were used to optimise the number of OS-EM iterations where the scatter estimate is updated and the number of MC simulated photons. The results showed that two scatter update iterations and 10(5) simulated photons are enough for the Tc-99m and Tl-201 reconstructions, whereas 10(6) simulated photons are needed to generate good quality down-scatter estimates. With these parameters, the entire Tl-201/Tc-99m dual isotope reconstruction can be accomplished in less than 3 minutes.

  1. Observer variability in the evaluation of dual-isotope Tl-201/Tc-99m sestamibi rest/stress myocardial perfusion SPECT in men and women with known or suspected stable angina pectoris

    DEFF Research Database (Denmark)

    Johansen, Allan; Høilund-Carlsen, Poul Flemming; Christensen, Henrik Wulff

    2004-01-01

    BACKGROUND: Observer variability of dual-isotope myocardial perfusion imaging (MPI) with single photon emission computed tomography has rarely been investigated. The aim of our study was to evaluate the interpretive reproducibility with this technique. METHODS AND RESULTS: We report on 507 patients...... with known or suspected stable angina who were studied before coronary angiography. A 1-day thallium 201/technetium 99m sestamibi rest/stress MPI protocol was used. MPI was interpreted by 2 independent observers without knowledge of clinical data, using a 20-segment scoring model. By consensus, the overall...... rate of abnormal MPI was 49% (59% in men and 34% in women). The interobserver agreement for the whole group (kappa = 0.85) and for men and women separately (kappa = 0.86 and 0.82, respectively) was excellent with regard to the overall diagnosis (normal, reversible, or fixed defects) as well as left...

  2. Dual isotope notch observer for isotope identification, assay and imaging with mono-energetic gamma-ray sources

    Science.gov (United States)

    Barty, Christopher P.J.

    2013-02-05

    A dual isotope notch observer for isotope identification, assay and imaging with mono-energetic gamma-ray sources includes a detector arrangement consists of three detectors downstream from the object under observation. The latter detector, which operates as a beam monitor, is an integrating detector that monitors the total beam power arriving at its surface. The first detector and the middle detector each include an integrating detector surrounding a foil. The foils of these two detectors are made of the same atomic material, but each foil is a different isotope, e.g., the first foil may comprise U235 and second foil may comprise U238. The integrating detectors surrounding these pieces of foil measure the total power scattered from the foil and can be similar in composition to the final beam monitor. Non-resonant photons will, after calibration, scatter equally from both foils.

  3. The suitability of the dual isotope approach (δ13C and δ18O) in tree ring studies

    Science.gov (United States)

    Siegwolf, Rolf; Saurer, Matthias

    2016-04-01

    The use of stable isotopes, complementary to tree ring width data in tree ring research has proven to be a powerful tool in studying the impact of environmental parameters on tree physiology and growth. These three proxies are thus instrumental for climate reconstruction and improve the understanding of underlying causes of growth changes. In various cases, however, their use suggests non-plausible interpretations. Often the use of one isotope alone does not allow the detection of such "erroneous isotope responses". A careful analysis of these deviating results shows that either the validity of the carbon isotope discrimination concept is no longer true (Farquhar et al. 1982) or the assumptions for the leaf water enrichment model (Cernusak et al., 2003) are violated and thus both fractionation models are not applicable. In this presentation we discuss such cases when the known fractionation concepts fail and do not allow a correct interpretation of the isotope data. With the help of the dual isotope approach (Scheidegger et al.; 2000) it is demonstrated, how to detect and uncover the causes for such anomalous isotope data. The fractionation concepts and their combinations before the background of CO2 and H2O gas exchange are briefly explained and the specific use of the dual isotope approach for tree ring data analyses and interpretations are demonstrated. References: Cernusak, L. A., Arthur, D. J., Pate, J. S. and Farquhar, G. D.: Water relations link carbon and oxygen isotope discrimination to phloem sap sugar concentration in Eucalyptus globules, Plant Physiol., 131, 1544-1554, 2003. Farquhar, G. D., O'Leary, M. H. and Berry, J. A.: On the relationship between carbon isotope discrimination and the intercellular carbon dioxide concentration in leaves, Aust. J. Plant Physiol., 9, 121-137, 1982. Scheidegger, Y., Saurer, M., Bahn, M. and Siegwolf, R.: Linking stable oxygen and carbon isotopes with stomatal conductance and photosynthetic capacity: A conceptual model

  4. 一种免疫荧光图像减影技术在鉴定drebrin E亚型的应用%Application of an immunofluorescence image subtraction technique in identification of drebrin isoform E

    Institute of Scientific and Technical Information of China (English)

    宋明桥; 迟晓冬; 郑文旭; 刘萍

    2011-01-01

    Objective; To identify the drebrin isoform E by a novel immunofluorescence image subtraction technique without drebrin E-specific antibody. Methods; We used drebrin-non-specific antibody M2F6 and drebrin A-specific antibody DAS2 to immunostain the frozen sections of the adult rat brain by double immunofluorescence staining. Then the two immunostaining images of the same section were processed with the image subtraction technique using a computer image processing software, and the expression of drebrin E in the adult rat brain was observed. Results; We obtained the images of drebrin isoform E by the immunofluorescence image subtraction technique. The expression of drebrin E in the rostral migratory stream, the dentate gyrus of the hippocampus and the piriform cortex of the adult rat brain was identified. Conclusion; The immunofluorescence image subtraction technique can identify the drebrin isoform E, and offer a novel approach to identify the proteins which have two isoforms similar to drebrin.%目的:在缺乏drebrin E抗体的情况下利用一种新的免疫荧光计算机图像减影技术的方法鉴定drebrin E亚型.方法:应用drebrin非特异性抗体M2F6和drebrin A特异性抗体DAS2对成年大鼠脑冰冻切片进行双重免疫荧光染色,然后用计算机图像处理软件对同一切片的两种染色照片进行图像减影技术处理,观察drebrin E在成年大鼠脑中的分布情况.结果:通过免疫荧光计算机图像减影技术得到了drebrin E亚型的图像,确认了drebrin E在成年大鼠脑中吻侧辽移流、海马齿状回、梨状皮质的分布.结论:利用免疫荧光图像减影技术可以实现对drebrin E亚型的鉴定,为类似drebrin这样存在两种亚型的蛋白质鉴定提供了一种新的方法.

  5. Quantitative image reconstruction for dual-isotope parathyroid SPECT/CT: phantom experiments and sample patient studies

    Science.gov (United States)

    Shcherbinin, S.; Chamoiseau, S.; Celler, A.

    2012-08-01

    We investigated the quantitative accuracy of the model-based dual-isotope single-photon emission computed tomography (DI-SPECT) reconstructions that use Klein-Nishina expressions to estimate the scattered photon contributions to the projection data. Our objective was to examine the ability of the method to recover the absolute activities pertaining to both radiotracers: Tc-99m and I-123. We validated our method through a series of phantom experiments performed using a clinical hybrid SPECT/CT camera (Infinia Hawkeye, GE Healthcare). Different activity ratios and different attenuating media were used in these experiments to create cross-talk effects of varying severity, which can occur in clinical studies. Accurate model-based corrections for scatter and cross-talk with CT attenuation maps allowed for the recovery of the absolute activities from DI-SPECT/CT scans with errors that ranged 0-10% for both radiotracers. The unfavorable activity ratios increased the computational burden but practically did not affect the resulting accuracy. The visual analysis of parathyroid patient data demonstrated that our model-based processing improved adenoma/background contrast and enhanced localization of small or faint adenomas.

  6. Water and light improvement after thinning at a xeric site: Which weights the most? A dual isotope approach

    Science.gov (United States)

    Giuggiola, Arnaud; Ogée, Jérôme; Gessler, Arthur; Rigling, Andreas; Bugmann, Harald; Treydte, Kerstin

    2015-04-01

    Reductions in stand density foster individual tree growth due to increases of resources such as water, light and nutrients. Detailed knowledge of the short- to long-term physiological response underlying the growth response to thinning is crucial for the management of forests already suffering from recurrent drought-induced dieback. We applied a dual isotope approach together with mechanistic isotope models such as MuSICA to study the physiological processes underlying growth enhancement in a long-term thinning experiment in a xeric Pinus sylvestris forest in Switzerland. This approach allowed for identifying and disentangling changes in stomatal conductance and assimilation rate. Our results indicate that an increase in stomatal conductance outweighs an increase in assimilation, meaning that the observed growth releases in heavy thinned trees at our xeric site are primarily driven by enhanced water availability rather than by the increase in light availability. We conclude that in areas with isohydric species (drought avoiders) that tend to grow close to their physiological limits, thinning is highly recommended to maintain a less negative water balance and thus foster tree growth, and ultimately the survival rate of individual trees and forests.

  7. Improvement of water and light availability after thinning at a xeric site: which matters more? A dual isotope approach.

    Science.gov (United States)

    Giuggiola, Arnaud; Ogée, Jérôme; Rigling, Andreas; Gessler, Arthur; Bugmann, Harald; Treydte, Kerstin

    2016-04-01

    Thinning fosters individual tree growth by increasing the availability of water, light and nutrients. At sites where water rather than light is limiting, thinning also enhances soil evaporation and might not be beneficial. Detailed knowledge of the short- to long-term physiological response underlying the growth responses to thinning is crucial for the management of forests already suffering from recurrent drought-induced dieback. We applied a dual isotope approach together with mechanistic isotope models to study the physiological processes underlying long-term growth enhancement of heavily thinned Pinus sylvestris in a xeric forest in Switzerland. This approach allowed us to identify and disentangle thinning-induced changes in stomatal conductance and assimilation rate. At our xeric study site, the increase in stomatal conductance far outweighed the increase in assimilation, implying that growth release in heavily thinned trees is primarily driven by enhanced water availability rather than increased light availability. We conclude that in forests with relatively isohydric species (drought avoiders) that are growing close to their physiological limits, thinning is recommended to maintain a less negative water balance and thus foster tree growth, and ultimately the survival of forest trees under drought. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

  8. Colourful FKS subtraction

    CERN Document Server

    Frixione, Stefano

    2011-01-01

    I formulate in a colour-friendly way the FKS method for the computation of QCD cross sections at the next-to-leading order accuracy. This is achieved through the definition of subtraction terms for squared matrix elements, constructed with single colour-dressed or pairs of colour-ordered amplitudes. The latter approach relies on the use of colour flows, is exact to all orders in $N$, and is thus particularly suited to being organized as a systematic expansion in 1/N.

  9. Nitrate source apportionment using a combined dual isotope, chemical and bacterial property, and Bayesian model approach in river systems

    Science.gov (United States)

    Xia, Yongqiu; Li, Yuefei; Zhang, Xinyu; Yan, Xiaoyuan

    2017-01-01

    Nitrate (NO3-) pollution is a serious problem worldwide, particularly in countries with intensive agricultural and population activities. Previous studies have used δ15N-NO3- and δ18O-NO3- to determine the NO3- sources in rivers. However, this approach is subject to substantial uncertainties and limitations because of the numerous NO3- sources, the wide isotopic ranges, and the existing isotopic fractionations. In this study, we outline a combined procedure for improving the determination of NO3- sources in a paddy agriculture-urban gradient watershed in eastern China. First, the main sources of NO3- in the Qinhuai River were examined by the dual-isotope biplot approach, in which we narrowed the isotope ranges using site-specific isotopic results. Next, the bacterial groups and chemical properties of the river water were analyzed to verify these sources. Finally, we introduced a Bayesian model to apportion the spatiotemporal variations of the NO3- sources. Denitrification was first incorporated into the Bayesian model because denitrification plays an important role in the nitrogen pathway. The results showed that fertilizer contributed large amounts of NO3- to the surface water in traditional agricultural regions, whereas manure effluents were the dominant NO3- source in intensified agricultural regions, especially during the wet seasons. Sewage effluents were important in all three land uses and exhibited great differences between the dry season and the wet season. This combined analysis quantitatively delineates the proportion of NO3- sources from paddy agriculture to urban river water for both dry and wet seasons and incorporates isotopic fractionation and uncertainties in the source compositions.

  10. Dual-isotope SPECT/CT impact on hospitalized patients with suspected diabetic foot infection: saving limbs, lives, and resources.

    Science.gov (United States)

    Heiba, Sherif; Kolker, Dov; Ong, Leonard; Sharma, Shalini; Travis, Arlene; Teodorescu, Victoria; Ellozy, Sharif; Kostakoglu, Lale; Savitch, Ina; Machac, Josef

    2013-09-01

    Foot ulcer with suspected infection is one of the most common reasons for hospitalization and a major factor contributing to morbidity and high healthcare-related expenses among diabetic patients. Many patients will require amputation; however, major amputation is associated with an alarmingly high 5-year mortality rate. In this study, we assess the diagnosis and management of suspected foot infection in diabetic patients using dual-isotope (DI) single-photon emission computed tomography/computed tomography (SPECT/CT) compared with conventional imaging. The diagnostic accuracy in and management of 227 patients who had undergone DI SPECT/CT was compared with that of 232 similar patients who had undergone conventional imaging including plain radiography, CT, planar bone scanning, planar indium-111 white blood cell scanning, and MRI. The duration of hospitalization was additionally compared between these two groups of patients after excluding patients with other active comorbidities. Soft-tissue infection, osteomyelitis with or without soft-tissue infection, and other bony pathologies were more accurately and confidently identified with DI SPECT/CT than with conventional imaging. DI SPECT/CT use was associated with significantly fewer major amputations and more selective bony resection as well as with shorter duration of hospitalization when compared with conventional imaging. In this large population of diabetic patients with suspected foot infection DI SPECT/CT was more accurate in diagnosing and localizing infection compared with conventional imaging. In addition, DI SPECT/CT provided clear guidance and promoted many limb salvage procedures. Of equal importance to health economics, DI SPECT/CT use was associated with considerably reduced length of hospitalization compared with conventional imaging.

  11. Investigating human geographic origins using dual-isotope (87Sr/86Sr, δ18O) assignment approaches

    Science.gov (United States)

    Sonnemann, Till F.; Shafie, Termeh; Hofman, Corinne L.; Brandes, Ulrik; Davies, Gareth R.

    2017-01-01

    Substantial progress in the application of multiple isotope analyses has greatly improved the ability to identify nonlocal individuals amongst archaeological populations over the past decades. More recently the development of large scale models of spatial isotopic variation (isoscapes) has contributed to improved geographic assignments of human and animal origins. Persistent challenges remain, however, in the accurate identification of individual geographic origins from skeletal isotope data in studies of human (and animal) migration and provenance. In an attempt to develop and test more standardized and quantitative approaches to geographic assignment of individual origins using isotopic data two methods, combining 87Sr/86Sr and δ18O isoscapes, are examined for the Circum-Caribbean region: 1) an Interval approach using a defined range of fixed isotopic variation per location; and 2) a Likelihood assignment approach using univariate and bivariate probability density functions. These two methods are tested with enamel isotope data from a modern sample of known origin from Caracas, Venezuela and further explored with two archaeological samples of unknown origin recovered from Cuba and Trinidad. The results emphasize both the potential and limitation of the different approaches. Validation tests on the known origin sample exclude most areas of the Circum-Caribbean region and correctly highlight Caracas as a possible place of origin with both approaches. The positive validation results clearly demonstrate the overall efficacy of a dual-isotope approach to geoprovenance. The accuracy and precision of geographic assignments may be further improved by better understanding of the relationships between environmental and biological isotope variation; continued development and refinement of relevant isoscapes; and the eventual incorporation of a broader array of isotope proxy data. PMID:28222163

  12. Identifying nitrate sources and transformations in surface water by combining dual isotopes of nitrate and stable isotope mixing model in a watershed with different land uses and multi-tributaries

    Science.gov (United States)

    Wang, Meng; Lu, Baohong

    2017-04-01

    Nitrate is essential for the growth and survival of plants, animals and humans. However, excess nitrate in drinking water is regarded as a health hazard as it is linked to infant methemoglobinemia and esophageal cancer. Revealing nitrate characteristics and identifying its sources are fundamental for making effective water management strategies, but nitrate sources in multi-tributaries and mixed land covered watersheds remain unclear. It is difficult to determine the predominant NO3- sources using conventional water quality monitoring techniques. In our study, based on 20 surface water sampling sites for more than two years' monitoring from April 2012 to December 2014, water chemical and dual isotopic approaches (δ15N-NO3- and δ18O-NO3-) were integrated for the first time to evaluate nitrate characteristics and sources in the Huashan watershed, Jianghuai hilly region, East China. The results demonstrated that nitrate content in surface water was relatively low in the downstream (<10 mg/L), but spatial heterogeneities were remarkable among different sub-watersheds. Extremely high nitrate was observed at the source of the river in one of the sub-watersheds, which exhibited an exponential decline along the stream due to dilution, absorption by aquatic plants, and high forest cover. Although dramatically decline of nitrate occurred along the stream, denitrification was not found in surface water by analyzing δ15N-NO3- and δ18O-NO3- relationship. Proportional contributions of five potential nitrate sources (i.e., precipitation; manure and sewage; soil nitrogen; nitrate fertilizer; nitrate derived from ammonia fertilizer and rainfall) were estimated using a Bayesian isotope mixing model. Model results indicated nitrate sources varied significantly among different rainfall conditions, land use types, as well as anthropologic activities. In summary, coupling dual isotopes of nitrate (δ15N-NO3- and δ18O-NO3-, simultaneously) with a Bayesian isotope mixing model offers

  13. [Construction of subtractive cDNA libraries of the sporogony stage of Eimeria tenella by suppression subtractive hybridization].

    Science.gov (United States)

    Han, Hong-Yu; Lin, Jiao-Jiao; Zhao, Qi-Ping; Dong, Hui; Jiang, Lian-Lian; Wang, Xin; Han, Jing-Fang; Huang, Bing

    2007-11-01

    In order to clone and identify differentially expressed genes in the sporogony stage of Eimeria tenella, the cDNAs from unsporulated oocysts and sporulated oocysts of E. tenella were used as driver, respectively, the cDNAs from sporozoites of E. tenella was used tester, Two subtractive cDNA libraries of sporozoites were constructed by using the technique of suppression subtractive hybridization (SSH). the cDNAs from unsporulated oocysts was used driver, the cDNAs from sporulated ooceysts was used tester, one subtractive cDNA library of sporulated oocysts was constructed. PCR amplification revealed that the two subtractive cDNA libraries of sporozoites and one subtractive cDNA library of sporulated oocysts contained approximated 96%, 96% and 98% recombinant clones, respectively. Fifty positive clones were sequenced and analyzed in GenBank with Blast search from three subtractive cDNA libraries, respectively, thirteen unique sequences were found from the subtractive cDNA library of sporulated oocysts, eight ESTs shared significant identity with previously described. A total of forty unique sequences were obtained from the two subtractive cDNA libraries, nine ESTs shared significant identity with previously described, the other sequences represent novel genes of E. tenella with no significant homology to the proteins in Genbank. These results have provided the foundation for cloning new genes of E. tenella and further studying new approaches to control coccidiosis.

  14. Background subtraction theory and practice

    CERN Document Server

    Elgammal, Ahmed

    2014-01-01

    Background subtraction is a widely used concept for detection of moving objects in videos. In the last two decades there has been a lot of development in designing algorithms for background subtraction, as well as wide use of these algorithms in various important applications, such as visual surveillance, sports video analysis, motion capture, etc. Various statistical approaches have been proposed to model scene backgrounds. The concept of background subtraction also has been extended to detect objects from videos captured from moving cameras. This book reviews the concept and practice of back

  15. Dual isotope plots reflect transformation pathways of pesticides: Potential to assess pesticide fate and elucidate transformation mechanisms

    Science.gov (United States)

    Meyer, Armin; Penning, Holger; Sorensen, Sebastian; Aamand, Jens; Elsner, Martin

    2010-05-01

    The degradation of pesticides in deeper soil layers and groundwater is of growing interest, because they have repeatedly been found in drinking water supply wells and may pose a risk to future water resources. Current assessment schemes face a common problem, however: natural degradation often cannot be reliably assessed by concentration measurements alone, since mass balances are difficult to establish and transformation cannot be distinguished from sorption or dilution. Even detection of metabolites may only give an incomplete picture. When several transformation pathways occur, some metabolites may be degraded or form bound residues so that the associated pathways may be missed. Our research shows that dual isotope plots derived from compound specific isotope analysis offer a novel approach to give additional, complementary insight into the natural degradation of pesticides. Detection of metabolites is not required, since the isotope fractionation can be fully observed in the pesticide itself. Specifically, different initial biotransformation reactions of the phenylurea herbicide isoproturon (3-(4-isopropylphenyl)-1,1-dimethylurea) in pure culture experiments with bacterial and fungal strains showed strongly pathway-dependent isotope fractionation. When analyzing isotopic changes in different parts of the isoproturon molecule, hydroxylation of the isopropyl group by fungi was found to be associated with C and H isotope fractionation. In contrast, hydrolysis by Arthrobacter globiformis D47 caused strong C and N isotope fractionation, albeit in a different manner than abiotic hydrolysis so that isotope measurements can distinguish between both modes of transformation. Likewise, we observed highly pathway-dependent C and N isotope fractionation of atrazine (1-chloro-3-ethylamino-5-isopropylamino-2,4,6-triazine). Desalkylation of atrazine by Rhodococcus sp. strain NI86/21 resulted in enrichment of both 13-C and 15-N in atrazine, whereas hydrolysis to hydroxyatrazine

  16. IR subtraction schemes. Integrating the counterterms at NNLO in QCD

    Energy Technology Data Exchange (ETDEWEB)

    Bolzoni, Paolo; Somogyi, Gabor

    2010-06-15

    We briefly review a subtraction scheme for computing radiative corrections to QCD jet cross sections that can be defined at any order in perturbation theory. Hereafter we discuss the computational methods used to evaluate analytically and numerically the integrated counterterms arising from such a subtraction scheme. Basically these methods the Mellin-Barnes (MB) representations technique together with the harmonic summation and the sector decomposition. (orig.)

  17. Blind foreground subtraction for intensity mapping experiments

    Science.gov (United States)

    Alonso, David; Bull, Philip; Ferreira, Pedro G.; Santos, Mário G.

    2015-02-01

    We make use of a large set of fast simulations of an intensity mapping experiment with characteristics similar to those expected of the Square Kilometre Array in order to study the viability and limits of blind foreground subtraction techniques. In particular, we consider three different approaches: polynomial fitting, principal component analysis (PCA) and independent component analysis (ICA). We review the motivations and algorithms for the three methods, and show that they can all be described, using the same mathematical framework, as different approaches to the blind source separation problem. We study the efficiency of foreground subtraction both in the angular and radial (frequency) directions, as well as the dependence of this efficiency on different instrumental and modelling parameters. For well-behaved foregrounds and instrumental effects, we find that foreground subtraction can be successful to a reasonable level on most scales of interest. We also quantify the effect that the cleaning has on the recovered signal and power spectra. Interestingly, we find that the three methods yield quantitatively similar results, with PCA and ICA being almost equivalent.

  18. Subtraction gadolinium enhanced magnetic resonance for head and neck imaging

    Energy Technology Data Exchange (ETDEWEB)

    Lloyd, G.A.S.; Barker, P.G.; Phelps, P.D. (Royal National Throat, Nose and Ear Hospital, London (United Kingdom))

    1993-01-01

    The subtraction method of Des Plantes was applied to gadolinium enhanced magnetic resonance imaging (GdMR). Using short acquisition times, T[sub 1] weighted spin echo pulse sequences are made immediately before and after intravenous administration of gadolinium DTPA. The needle is placed in the vein prior to putting the patient into the scanner and is irrigated with saline while the control series is obtained. 42 patients with naso-sinus or skull base tumours have been successfully investigated by this technique and satisfactory subtraction studies are now obtained on all patients other than the claustrophobic. Subtraction GdMR provides the best demonstration of the effects of gadolinium DTPA on the magnetic resonance signal for both normal and abnormal tissues. Tbe signal recorded on the subtraction image is dependent on tissue blood supply and provides a more accurate record of tumour extent than that shown by unsubtracted GdMR scans. (author).

  19. Advanced Background Subtraction Applied to Aeroacoustic Wind Tunnel Testing

    Science.gov (United States)

    Bahr, Christopher J.; Horne, William C.

    2015-01-01

    An advanced form of background subtraction is presented and applied to aeroacoustic wind tunnel data. A variant of this method has seen use in other fields such as climatology and medical imaging. The technique, based on an eigenvalue decomposition of the background noise cross-spectral matrix, is robust against situations where isolated background auto-spectral levels are measured to be higher than levels of combined source and background signals. It also provides an alternate estimate of the cross-spectrum, which previously might have poor definition for low signal-to-noise ratio measurements. Simulated results indicate similar performance to conventional background subtraction when the subtracted spectra are weaker than the true contaminating background levels. Superior performance is observed when the subtracted spectra are stronger than the true contaminating background levels. Experimental results show limited success in recovering signal behavior for data where conventional background subtraction fails. They also demonstrate the new subtraction technique's ability to maintain a proper coherence relationship in the modified cross-spectral matrix. Beam-forming and de-convolution results indicate the method can successfully separate sources. Results also show a reduced need for the use of diagonal removal in phased array processing, at least for the limited data sets considered.

  20. Color Addition and Subtraction Apps

    Science.gov (United States)

    Ruiz, Frances; Ruiz, Michael J.

    2015-10-01

    Color addition and subtraction apps in HTML5 have been developed for students as an online hands-on experience so that they can more easily master principles introduced through traditional classroom demonstrations. The evolution of the additive RGB color model is traced through the early IBM color adapters so that students can proceed step by step in understanding mathematical representations of RGB color. Finally, color addition and subtraction are presented for the X11 colors from web design to illustrate yet another real-life application of color mixing.

  1. Fusion and subtraction post-processing in body MRI

    Energy Technology Data Exchange (ETDEWEB)

    Watson, Tom A.; Olsen, Oeystein E. [Great Ormond Street Hospital for Children NHS Foundation Trust, Department of Radiology, London (United Kingdom)

    2014-09-02

    Interpreting complex paediatric body MRI studies requires the integration of information from multiple sequences. Image processing software, some freely available, allows the radiologist to use simple and rapid post-processing techniques that may aid diagnosis. We demonstrate the use of fusion and subtraction post-processing techniques with examples from four areas of application: enterography, oncological imaging, musculoskeletal imaging and MR fistulography. (orig.)

  2. Suppression subtractive hybridization: a method for generating differentially regulated or tissue-specific cDNA probes and libraries.

    OpenAIRE

    1996-01-01

    A new and highly effective method, termed suppression subtractive hybridization (SSH), has been developed for the generation of subtracted cDNA libraries. It is based primarily on a recently described technique called suppression PCR and combines normalization and subtraction in a single procedure. The normalization step equalizes the abundance of cDNAs within the target population and the subtraction step excludes the common sequences between the target and driver populations. In a model sys...

  3. Comparison of the imaging performances for recently developed monolithic scintillators: CRY018 and CRY019 for dual isotope gamma ray imaging applications

    Science.gov (United States)

    Polito, C.; Pani, R.; Trigila, C.; Cinti, M. N.; Fabbri, A.; Frantellizzi, V.; De Vincentis, G.; Pellegrini, R.; Pani, R.

    2017-01-01

    The growing interest for new scintillation crystals with outstanding imaging performances (i.e. resolution and efficiency) has suggested the study of recently discovered scintillators named CRY018 and CRY019. The crystals under investigation are monolithic and have shown enhanced characteristics both for gamma ray spectrometry and for Nuclear Medicine imaging applications such as the dual isotope imaging. Moreover, the non-hygroscopic nature and the absence of afterglow make these scintillators even more attractive for the potential improvement in a wide range of applications. These scintillation crystals show a high energy resolution in the energy range involved in Nuclear Medicine, allowing the discrimination between very close energy values. Moreover, in order to prove their suitability of being powerful imaging systems, the imaging performances like the position linearity and the intrinsic spatial resolution have been evaluated obtaining satisfactory results thanks to the implementation of an optimized algorithm for the images reconstruction.

  4. Single Stress Dual-Isotope Myocardial Perfusion Imaging using 99mTc SPECT and 82Rb PET: A Phantom Study

    DEFF Research Database (Denmark)

    Christensen, Nana Louise; Gormsen, Lars Christian; Tolbod, Lars Poulsen

    Aim: Technetium-99m SPECT and rubidium-82 PET are two well established MPI modalities that have been used for decades in the diagnosis of cardiovascular diseases. In previous comparison studies, the patients underwent pharmacological stress imaging in different days, thereby complicating the eval......Aim: Technetium-99m SPECT and rubidium-82 PET are two well established MPI modalities that have been used for decades in the diagnosis of cardiovascular diseases. In previous comparison studies, the patients underwent pharmacological stress imaging in different days, thereby complicating...... corrections. Furthermore, visual inspection of the images showed no influence from the 99mTc-sestamibi tracer in the PET images either. Conclusion: The 82Rb PET images are not affected by the presence of 99mTc-sestamibi, allowing for single stress sameday protocols of dual-isotope/dual-modality MPI studies...

  5. Behavior Subtraction applied to radar

    NARCIS (Netherlands)

    Rossum, W.L. van; Caro Cuenca, M.

    2014-01-01

    An algorithm developed for optical images has been applied to radar data. The algorithm, Behavior Subtraction, is based on capturing the dynamics of a scene and detecting anomalous behavior. The radar application is the detection of small surface targets at sea. The sea surface yields the expected s

  6. Color Addition and Subtraction Apps

    Science.gov (United States)

    Ruiz, Frances; Ruiz, Michael J.

    2015-01-01

    Color addition and subtraction apps in HTML5 have been developed for students as an online hands-on experience so that they can more easily master principles introduced through traditional classroom demonstrations. The evolution of the additive RGB color model is traced through the early IBM color adapters so that students can proceed step by step…

  7. Color Addition and Subtraction Apps

    Science.gov (United States)

    Ruiz, Frances; Ruiz, Michael J.

    2015-01-01

    Color addition and subtraction apps in HTML5 have been developed for students as an online hands-on experience so that they can more easily master principles introduced through traditional classroom demonstrations. The evolution of the additive RGB color model is traced through the early IBM color adapters so that students can proceed step by step…

  8. Using Dual Isotopes and a Bayesian Isotope Mixing Model to Evaluate Nitrate Sources of Surface Water in a Drinking Water Source Watershed, East China

    Directory of Open Access Journals (Sweden)

    Meng Wang

    2016-08-01

    Full Text Available A high concentration of nitrate (NO3− in surface water threatens aquatic systems and human health. Revealing nitrate characteristics and identifying its sources are fundamental to making effective water management strategies. However, nitrate sources in multi-tributaries and mix land use watersheds remain unclear. In this study, based on 20 surface water sampling sites for more than two years’ monitoring from April 2012 to December 2014, water chemical and dual isotopic approaches (δ15N-NO3− and δ18O-NO3− were integrated for the first time to evaluate nitrate characteristics and sources in the Huashan watershed, Jianghuai hilly region, China. Nitrate-nitrogen concentrations (ranging from 0.02 to 8.57 mg/L were spatially heterogeneous that were influenced by hydrogeological and land use conditions. Proportional contributions of five potential nitrate sources (i.e., precipitation; manure and sewage, M & S; soil nitrogen, NS; nitrate fertilizer; nitrate derived from ammonia fertilizer and rainfall were estimated by using a Bayesian isotope mixing model. The results showed that nitrate sources contributions varied significantly among different rainfall conditions and land use types. As for the whole watershed, M & S (manure and sewage and NS (soil nitrogen were major nitrate sources in both wet and dry seasons (from 28% to 36% for manure and sewage and from 24% to 27% for soil nitrogen, respectively. Overall, combining a dual isotopes method with a Bayesian isotope mixing model offered a useful and practical way to qualitatively analyze nitrate sources and transformations as well as quantitatively estimate the contributions of potential nitrate sources in drinking water source watersheds, Jianghuai hilly region, eastern China.

  9. Sensitivity and Specificity of Dual-Isotope 99mTc-Tetrofosmin and 123I Sodium Iodide Single Photon Emission Computed Tomography (SPECT) in Hyperparathyroidism.

    Science.gov (United States)

    Sommerauer, Michael; Graf, Carmen; Schäfer, Niklaus; Huber, Gerhard; Schneider, Paul; Wüthrich, Rudolf; Schmid, Christoph; Steinert, Hans

    2015-01-01

    Despite recommendations for 99mTc-tetrofosmin dual tracer imaging for hyperparathyroidism in current guidelines, no report was published on dual-isotope 99mTc-tetrofosmin and 123I sodium iodide single-photon-emission-computed-tomography (SPECT). We evaluated diagnostic accuracy and the impact of preoperative SPECT on the surgical procedures and disease outcomes. Analysis of 70 consecutive patients with primary hyperparathyroidism and 20 consecutive patients with tertiary hyperparathyroidism. Imaging findings were correlated with surgical results. Concomitant thyroid disease, pre- and postoperative laboratory measurements, histopathological results, type and duration of surgery were assessed. In primary hyperparathyroidism, SPECT had a sensitivity of 80% and a positive predictive value of 93% in patient-based analysis. Specificity was 99% in lesion-based analysis. Patients with positive SPECT elicit higher levels of parathyroid hormone and higher weight of resected parathyroids than SPECT-negative patients. Duration of parathyroid surgery was on average, approximately 40 minutes shorter in SPECT-positive than in SPECT-negative patients (89 ± 46 vs. 129 ± 41 minutes, p = 0.006); 86% of SPECT-positive and 50% of SPECT-negative patients had minimal invasive surgery (p = 0.021). SPECT had lower sensitivity (60%) in patients with tertiary hyperparathyroidism; however, 90% of these patients had multiple lesions and all of these patients had bilateral lesions. Dual-isotope SPECT with 99mTc-tetrofosmin and 123I sodium iodide has a high diagnostic value in patients with primary hyperparathyroidism and allows for saving of operation time. Higher levels of parathyroid hormone and higher glandular weight facilitated detection of parathyroid lesion. Diagnostic accuracy of preoperative imaging was lower in patients with tertiary hyperparathyroidism.

  10. Sci-Fri AM: Imaging - 09: Serial estimation of cross-talk for correction in dual-isotope imaging with dynamic tracers.

    Science.gov (United States)

    Wells, R G; Lockwood, J; Wei, L; Duan, D; Fernando, P; Bensimon, C; Ruddy, T D

    2012-07-01

    The recent radioisotope shortage has led to interest in non-Tc99m-based tracers. We have developed a novel I-123-labelled myocardial perfusion imaging tracer. We compare the I123-tracer to the clinical standard of Tc99m tetrofosmin in vivo in a rat model using a small-animal SPECT/CT camera. SPECT distinguishes different isotopes based on the different energies of the emitted gamma rays and thus allows simultaneous comparison of two tracer distributions in the same animal. Dual-isotope imaging is complicated by cross-talk between the energy windows of the isotopes. Standard energy-window-based correction methods are difficult to employ because of the proximity in energy of Tc99m (140keV) and I123 (159keV). Imaging the second tracer's energy window prior to its injection provides an estimate of the cross-talk. However, this estimate is only accurate if the tracer distribution is static. We use serial imaging prior to the introduction of the second tracer to estimate the dynamics of the first tracer and interpolate the cross-talk images to provide a more accurate correction. We used rat models of myocardial disease (n=3). I123 tracer was injected and imaged for one hour at 20min intervals. The Tc99m tetrofosmin was then injected and 30min later, a dual-isotope image was obtained. The impact of this approach is assessed by comparing the differences in the Tc99m-tetrofosmin image using this method with correction by simple correction for physical decay. The interpolative approach improves the accuracy of the correction by 2%-5% and thereby enhances the comparison of the two tracers. © 2012 American Association of Physicists in Medicine.

  11. Astronomical Image Subtraction by Cross-Convolution

    Science.gov (United States)

    Yuan, Fang; Akerlof, Carl W.

    2008-04-01

    In recent years, there has been a proliferation of wide-field sky surveys to search for a variety of transient objects. Using relatively short focal lengths, the optics of these systems produce undersampled stellar images often marred by a variety of aberrations. As participants in such activities, we have developed a new algorithm for image subtraction that no longer requires high-quality reference images for comparison. The computational efficiency is comparable with similar procedures currently in use. The general technique is cross-convolution: two convolution kernels are generated to make a test image and a reference image separately transform to match as closely as possible. In analogy to the optimization technique for generating smoothing splines, the inclusion of an rms width penalty term constrains the diffusion of stellar images. In addition, by evaluating the convolution kernels on uniformly spaced subimages across the total area, these routines can accommodate point-spread functions that vary considerably across the focal plane.

  12. The concept of apparent cardiac arrest as a prerequisite for coronary digital subtraction angiography

    NARCIS (Netherlands)

    Werf, T. van der; Heethaar, R.M.; Stegehuis, H.; Meijler, F.L.

    1984-01-01

    This study was undertaken to evaluate the possible use of digital subtraction applied after selective coronary arteriography. An identical position of the objects with and without contrast medium is an absolute requirement for the application of subtraction techniques. Because coronary arteries are

  13. Blind Source Separation Algorithms for PSF Subtraction from Direct Imaging

    Science.gov (United States)

    Shapiro, Jacob; Ranganathan, Nikhil; Savransky, Dmitry; Ruffio, Jean-Baptise; Macintosh, Bruce; GPIES Team

    2017-01-01

    The principal difficulty with detecting planets via direct imaging is that the target signal is similar in magnitude, or fainter, than the noise sources in the image. To compensate for this, several methods exist to subtract the PSF of the host star and other confounding noise sources. One of the most effective methods is Karhunen-Loève Image Processing (KLIP). The core algorithm within KLIP is Principal Component Analysis, which is a member of a class of algorithms called Blind Source Separation (BSS).We examine three other BSS algorithms that may potentially also be used for PSF subtraction: Independent Component Analysis, Stationary Subspace Analysis, and Common Spatial Pattern Filtering. The underlying principles of each of the algorithms is discussed, as well as the processing steps needed to achieve PSF subtraction. The algorithms are examined both as primary PSF subtraction techniques, as well as additional postprocessing steps used with KLIP.These algorithms have been used on data from the Gemini Planet Imager, analyzing images of β Pic b. To build a reference library, both Angular Differential Imaging and Spectral Differential Imaging were used. To compare to KLIP, three major metrics are examined: computation time, signal-to-noise ratio, and astrometric and photometric biases in different image regimes (e.g., speckle-dominated compared to Poisson-noise dominated). Preliminary results indicate that these BSS algorithms improve performance when used as an enhancement for KLIP, and that they can achieve similar SNR when used as the primary method of PSF subtraction.

  14. Appearance of the canine meninges in subtraction magnetic resonance images.

    Science.gov (United States)

    Lamb, Christopher R; Lam, Richard; Keenihan, Erin K; Frean, Stephen

    2014-01-01

    The canine meninges are not visible as discrete structures in noncontrast magnetic resonance (MR) images, and are incompletely visualized in T1-weighted, postgadolinium images, reportedly appearing as short, thin curvilinear segments with minimal enhancement. Subtraction imaging facilitates detection of enhancement of tissues, hence may increase the conspicuity of meninges. The aim of the present study was to describe qualitatively the appearance of canine meninges in subtraction MR images obtained using a dynamic technique. Images were reviewed of 10 consecutive dogs that had dynamic pre- and postgadolinium T1W imaging of the brain that was interpreted as normal, and had normal cerebrospinal fluid. Image-anatomic correlation was facilitated by dissection and histologic examination of two canine cadavers. Meningeal enhancement was relatively inconspicuous in postgadolinium T1-weighted images, but was clearly visible in subtraction images of all dogs. Enhancement was visible as faint, small-rounded foci compatible with vessels seen end on within the sulci, a series of larger rounded foci compatible with vessels of variable caliber on the dorsal aspect of the cerebral cortex, and a continuous thin zone of moderate enhancement around the brain. Superimposition of color-encoded subtraction images on pregadolinium T1- and T2-weighted images facilitated localization of the origin of enhancement, which appeared to be predominantly dural, with relatively few leptomeningeal structures visible. Dynamic subtraction MR imaging should be considered for inclusion in clinical brain MR protocols because of the possibility that its use may increase sensitivity for lesions affecting the meninges.

  15. Accurate Sky Continuum Subtraction with Fibre-fed Spectrographs

    CERN Document Server

    Yang, Yanbin; Puech, Mathieu; Flores, Hector; Royer, Frederic; Disseau, Karen; Gonçalves, Thiago; Hammer, François; Cirasuolo, Michele; Evans, Chris; Causi, Gianluca Li; Maiolino, Roberto; Melo, Claudio

    2013-01-01

    Fibre-fed spectrographs now have throughputs equivalent to slit spectrographs. However, the sky subtraction accuracy that can be reached has often been pinpointed as one of the major issues associated with the use of fibres. Using technical time observations with FLAMES-GIRAFFE, two observing techniques, namely dual staring and cross beam-switching, were tested and the resulting sky subtraction accuracy reached in both cases was quantified. Results indicate that an accuracy of 0.6% on sky subtraction can be reached, provided that the cross beam-switching mode is used. This is very encouraging with regard to the detection of very faint sources with future fibre-fed spectrographs, such as VLT/MOONS or E-ELT/MOSAIC.

  16. Construction of a metastasis-associated gene subtracted cDNA library of human colorectal carcinoma by suppression subtraction hybridization

    Institute of Scientific and Technical Information of China (English)

    Li Liang; Yan-Qing Ding; Xin Li; Guang-Zhi Yang; Jun Xiao; Li-Chun Lu; Jin-Hua Zhang

    2004-01-01

    AIM: To construct a differentially-expressed gene subtracted cDNA library from two colorectal carcinoma (CRC) cell lines with different metastatic phenotypes by suppression subtractive hybridization.METHODS: Two cell lines of human CRC from the same patient were used. SW620 cell line showing highly metastatic potential was regarded as tester in the forward subtractive hybridization, while SW480 cell line with lowly metastatic potential was treated as tester in the reverse hybridization. Suppression subtractive hybridization (SSH)was employed to obtain cDNA fragments of differentially expressed genes for the metastasis of CRC. These fragments were ligated with T vectors, screened through the bluewhite screening system to establish cDNA library.RESULTS: After the blue-white screening, 235 white clones were picked out from the positive-going hybridization and 232 from the reverse. PCR results showed that 200-700 bp inserts were seen in 98% and 91% clones from the forward and reverse hybridizations, respectively.CONCLUSIONS: A subtractive cDNA library of differentially expressed genes specific for metastasis of CRC can be constructed with SSH and T/A cloning techniques.

  17. Image Segmentation in Video Sequences Using Modified Background Subtraction

    Directory of Open Access Journals (Sweden)

    D. W. Chinchkhede

    2012-03-01

    Full Text Available In computer vision, "Background subtraction" is a technique for finding moving objects in a video sequences for example vehicle driving on a freeway. For to detect non stationary (dynamic objects, it is necessary to subtracting current image from a time-averaged background image. There are various background subtraction algorithms for detecting moving vehicles or any moving object(s like pedestrians in urban traffic video sequences. A crude approximation to the task of classifying each pixel on the frame of current image, locate slow-moving objects or in poor image qualities of videos and distinguish shadows from moving objects by using modified background subtraction method. While classifying each pixel on the frame of the current image, it is to be detect the moving object at foreground and background conditional environment that we can classify each pixel using a model of how that pixellooks when it is part of video frame classes. A mixture of Gaussians classification model for each pixel using an unsupervised technique is an efficient, incremental version of Expectation Maximization (EM is used for the purpose. Unlike standard image-averaging approach, this method automatically updates the mixture component for each video frame class according to likelihood of membership; hence slowmoving objects and poor image quality of videos are also being handled perfectly. Our approach identifies and eliminates shadows much more effectively than other techniques like thresholding.

  18. Assessing sources of nitrate contamination in the Shiraz urban aquifer (Iran) using the δ(15)N and δ(18)O dual-isotope approach.

    Science.gov (United States)

    Amiri, Haleh; Zare, Mohammad; Widory, David

    2015-01-01

    Nitrate ([Formula: see text]) is one of the major threats to the quality of the drinking water taken from the Shiraz aquifer. This aquifer undergoes high anthropogenic pressures from multiple local urban (including uncontrolled sewage systems), agricultural and industrial activities, resulting in [Formula: see text] concentrations as high as 149 mg L(-1), well above the 50 mg L(-1) guideline defined by the World Health Organisation. We coupled here classical chemical and dual isotope (δ(15)N and δ(18)O of [Formula: see text]) approaches trying to characterize sources and potential processes controlling the budget of this pollutant. Chemical data indicate that nitrate in this aquifer is explained by distinct end-members: while mineral fertilizers isotopically show to have no impact, our isotope approach identifies natural soil nitrification and organic [Formula: see text] (manure and/or septic waste) as the two main contributors. Isotope data suggest that natural denitrification may occur within the aquifer, but this conclusion is not supported by the study of other chemical parameters.

  19. An Ultrahigh Precision, High-Frequency Dissolved Inorganic Carbon Analyzer Based on Dual Isotope Dilution and Cavity Ring-Down Spectroscopy.

    Science.gov (United States)

    Huang, Kuan; Cassar, Nicolas; Jonsson, Bror; Cai, Wei-jun; Bender, Michael L

    2015-07-21

    We present a novel method for continuous and automated shipboard measurements of dissolved inorganic carbon concentration ([DIC]) in surface water. The method is based on dual isotope dilution and cavity ring-down spectroscopy (DID-CRDS). In this method, seawater is continuously sampled and mixed with a flow of NaH(13)CO3 solution that is also enriched in deuterated water (the spike). The isotopic composition of CO2 (δ(13)C(spiked_sample)) derived from the DIC in the mixture, and the D/H ratio of the mixed water (δD(spiked_sample)), are measured by CRDS analyzers. The D/H of the water in the mixture allows accurate estimates of the mixing ratio of the sample and the spike. [DIC] of the sample is then calculated from the mixing ratio, [DI(13)C] of the spike, and δ(13)C(spiked_sample). In the laboratory, the precision of the method is test was conducted in the Delaware Bay and Estuary. For 2 min average [DIC], a precision of <0.03% was achieved. Measurements from the DID-CRDS showed good agreement with independent measurements of discrete samples using the well-established coulometric method (mean difference = -1.14 ± 1.68 μmol kg(-1)), and the nondispersive infrared(NDIR)-based methods (mean difference = -0.9 ± 4.73 μmol kg(-1)).

  20. Clinical value of dual-isotope fat absorption test system (FATS) using glycerol (/sup 125/I)trioleate and glycerol (/sup 75/Se)triether

    Energy Technology Data Exchange (ETDEWEB)

    Lembcke, B.; Loesler, A.C.; Caspary, W.F.; Schuernbrand, P.E.; Emrich, D.; Creutzfeldt, W.

    1986-08-01

    In order to delineate the clinical value of a dual-isotope fat absorption test system (FATS) using glycerol (/sup 75/Se)triether as lipid-phase marker and glycerol (/sup 125/I)trioleate as the test lipid, fecal isotope ratios from single stools (and a 72-hr stool homogenate) were compared to quantitative fecal fat excretion. The study included 11 patients without and 24 patients with steatorrhea. With a figure of 0.8% as the upper limit of normal, the test was a reliable indicator of steatorrhea with 87.5% sensitivity and 81.8% specificity; efficiency was 85.7%. Related to a prevalence of steatorrhea of 45.9% as the mean value of 1269 consecutive 72-hr specimens investigated for steatorrhea during 1978-1982, the positive (negative) predictive value of the FATS is 80.3% (87.2%). With 2% as the upper limit of normal, no false positive results ensued. It is concluded that a two-step interpretation of the FATS (0.8% limit and 2% limit) may be regarded a valid qualitative index for steatorrhea. The FATS isotope ratio using single stools correlated well with FATS ratios in the 72-hr stool homogenates (r = 0.97). FATS therefore allows a convenient estimate of steatorrhea from measuring single stools. As a quantitative measure of fecal fat excretion, the FATS is unreliable.

  1. Myocardial scintigraphy with iodine-123 phenylpentadecanoic acid and thallium-201 in patients with coronary artery disease: A comparative dual-isotope study

    Energy Technology Data Exchange (ETDEWEB)

    Zimmermann, R.; Rauch, B.; Kapp, M.; Neumann, F.J.; Seitz, F.; Kuebler, W. (Heidelberg Univ. (Germany). Dept. of Cardiology); Bubeck, B. (Heidelberg Univ. (Germany). Dept. of Nuclear Medicine); Mall, G. (Heidelberg Univ. (Germany). Dept. of Pathology); Tillmanns, H. (Giessen Univ. (Germany). Dept. of Cardiology); Stokstad, P.

    1992-11-01

    To characterise the clinical usefulness of serial myocardial scintigraphy with iodine-123 phenylpentadecanoic acid (IPPA) in comparison with thallium-201, dual-isotope investigations were performed in 41 patients with angiographically documented coronary artery disease. Both tracers were adminstered simultaneously during symptom-limited ergometry. Planar scintigrams were acquired immediately after stress, and delayed imaging was performed after 1 h for IPPA and 4 h for {sup 201}Tl. Scintigrams were evaluated both qualitatively and quantitatively using a newly developed algorithm for automated image superposition. Initial myocardial uptake of both tracers was closely correlated (r=0.75, p<0.001). Both tracers also revealed a similar sensitivity for the identification of individual coronary artery stenoses {>=}75% (IPPA: 70%, {sup 201}Tl: 66.3%, P=NS) with identical specificity (69.8%). The number of persistent defects, however, was significantly higher with IPPA (P=0.021), suggesting that visual analysis of serial IPPA scintigrams may overestimate the presence of myocardial scar tissue. On the other hand, previous Q wave myocardial infarction was associated with a decreased regional IPPA clearance (29%{+-}11% vs 44%{+-}11% in normal myocardium, P<0.05). The data indicate that serial myocardial scintigraphy with IPPA is essentially as sensitive as scintigraphy with {sup 201}Tl for the detection of stress-induced perfusion abnormalities. Quantitative analysis of myocardial IPPA kinetics, however, is required for the evaluation of tissue viability. (orig.).

  2. Eigenspectrum Noise Subtraction Methods in Lattice QCD

    CERN Document Server

    Guerrero, Victor; Wilcox, Walter

    2010-01-01

    We propose a new noise subtraction method, which we call "eigenspectrum subtraction", which uses low eigenmode information to suppress statistical noise at low quark mass. This is useful for lattice calculations involving disconnected loops or all-to-all propagators. It has significant advantages over perturbative subtraction methods. We compare unsubtracted, eigenspectrum and perturbative error bar results for the scalar operator on a small Wilson QCD matrix.

  3. Robust Background Subtraction with Foreground Validation for Urban Traffic Video

    Energy Technology Data Exchange (ETDEWEB)

    Cheung, S S; Kamath, C

    2004-01-15

    Identifying moving objects in a video sequence is a fundamental and critical task in many computer-vision applications. Background subtraction techniques are commonly used to separate foreground moving objects from the background. Most background subtraction techniques assume a single rate of adaptation, which is inadequate for complex scenes such as a traffic intersection where objects are moving at different and varying speeds. In this paper, we propose a foreground validation algorithm that first builds a foreground mask using a slow-adapting Kalman filter, and then validates individual foreground pixels by a simple moving object model, built using both the foreground and background statistics as well as the frame difference. Ground-truth experiments with urban traffic sequences show that our proposed algorithm significantly improves upon results using only Kalman filter or frame-differencing, and outperforms other techniques based on mixture of Gaussians, median filter, and approximated media filter.

  4. Speech Enhancement with Geometric Advent of Spectral Subtraction using Connected Time-Frequency Regions Noise Estimation

    Directory of Open Access Journals (Sweden)

    Nasir Saleem

    2013-06-01

    Full Text Available Speech enhancement with Geometric Advent of Spectral subtraction using connected time-frequency regions noise estimation aims to de-noise or reduce background noise from the noisy speech for better quality, pleasantness and improved intelligibility. Numerous enhancement methods are proposed including spectral subtraction, subspace, statistical with different noise estimations. The traditional spectral subtraction techniques are reasonably simple to implement and suffer from musical noise. This study addresses the new approach for speech enhancement which has minimized the insufficiencies in traditional spectral subtraction algorithms using MCRA. This approach with noise estimation has been evolved with PESQ, the ITU-T standard; Frequency weighted segmental SNR and weighted spectral slope. The analysis shows that Geometric approach with time-frequency connected regions has improved results than old-fashioned spectral subtraction algorithms. The normal hearing tests has suggested that new approach has lower audible musical noise.

  5. Analysis of the Clinical Value of DR Dual Energy Subtraction Technique in the Diagnosis of Aortic Calcification%DR双能量减影技术对主动脉钙化的诊断价值

    Institute of Scientific and Technical Information of China (English)

    吴晓玉; 李炯; 吕秀玲

    2015-01-01

    目的:评价阅砸双能量减影技术检测维持性血液透析(MHD)患者主动脉钙化的敏感性。方法抽取我院47例主动脉MSCT扫描钙化呈阳性且MSCT结果钙化严重程度为1~3级的MHD患者,再行阅砸双能量减影技术侧位胸片、侧位腹平检查。然后把图像分为两组院A组仅有阅砸标准图像,B组为阅砸标准图像和软组织影像院两组诊断医师分别对两组图像盲法阅片。分析两组结果有无差异。结果 A组94幅图像中57幅为阳性,阳性率为60.6%;B组94幅图像中76幅为阳性,阳性率为76.8%。结论在检测维持性血液透析(MHD)患者主动脉钙化的敏感性上阅砸双能量减影技术所得图像优于普通阅砸标准图像。%Objective To evaluate the sensitivity DR dual-energy subtraction (DES) in the diagnosis of aorta calcification in maintenance hemodialysis (MHD)patients. Methods 48 patients with the severity of aorta calcification by MSCT was graded from score 1 to 3 underwent DR dual-energy subtraction of lateral chest and lateral abdomen in our hospital. And then the results wil be divided into two groups:group A is DR images;group A is DR images and DES soft tissue images. Two grounps radiologists independent analyzed the results . Results The calcification rate of aorta was 60.6%in grounp A; The calcification rate of aorta was 76.8% in grounp B. Conclusion DR dual-energy subtraction technifque is superior to regular DR images in show aorta calcification in maintenance hemodialysis(MHD)patients.

  6. Dual-energy subtraction radiography of the breast

    Energy Technology Data Exchange (ETDEWEB)

    Asaga, Taro; Masuzawa, Chihiro; Kawahara, Satoru; Motohashi, Hisahiko; Okamoto, Takashi; Tamura, Nobuo

    1988-06-01

    Dual-energy projection radiography was applied to breast examination. To perform the dual-energy subtraction radiography using a digital radiography unit, high and low-energy exposures were made at an appropriate time interval under differing X-ray exposure conditions. Dual-energy subtraction radiography was performed in 41 cancer patients in whom the tumor shadow was equivocal or the border of cancer infiltration was not clearly demonstrated by compression mammography, and 15 patients with benign diseases such as fibrocystic disease, cyst and fibroadenoma. In 21 cases out of the 41 cancer patients, the dual-energy subtraction radiography clearly visualized the malignant tumor shadows and the border of cancer infiltration and the daughter nodules by removing the shadows of normal mammary gland. On the other hand, beign diseases such as fibrocystic disease and cyst could be diagnosed as such, because the tumor shadow and the irregularly concentrated image of mammary gland disappeared by the dual-energy subtraction. These results suggest that this new technique will be useful in examination of breast masses.

  7. Contexts for Column Addition and Subtraction

    Science.gov (United States)

    Lopez Fernandez, Jorge M.; Velazquez Estrella, Aileen

    2011-01-01

    In this article, the authors discuss their approach to column addition and subtraction algorithms. Adapting an original idea of Paul Cobb and Erna Yackel's from "A Contextual Investigation of Three-Digit Addition and Subtraction" related to packing and unpacking candy in a candy factory, the authors provided an analogous context by…

  8. Contexts for Column Addition and Subtraction

    Science.gov (United States)

    Lopez Fernandez, Jorge M.; Velazquez Estrella, Aileen

    2011-01-01

    In this article, the authors discuss their approach to column addition and subtraction algorithms. Adapting an original idea of Paul Cobb and Erna Yackel's from "A Contextual Investigation of Three-Digit Addition and Subtraction" related to packing and unpacking candy in a candy factory, the authors provided an analogous context by…

  9. Imaging of brain tumors in AIDS patients by means of dual-isotope thallium-201 and technetium-99m sestamibi single-photon emission tomography

    Energy Technology Data Exchange (ETDEWEB)

    De La Pena, R.C.; Ketonen, L.; Villanueva-Meyer, J. [Dept. of Radiology, Univ. of Texas, Galveston (United States)

    1998-10-01

    Our aim was to evaluate the use of dual-isotope thallium-201 (Tl) and technetium-99m sestamibi (sestamibi) simultaneous acquisition in brain single-photon emission tomography (SPET) for the differentiation between brain lymphoma and benign central nervous system (CNS) lesions in AIDS patients. Thirty-six consecutive patients with enhancing mass lesions on magnetic resonance (MR) imaging were included in the study. SPET of the brain was performed to obtain simultaneous Tl and sestamibi images. Regions-of-interest were drawn around the lesion and on the contralateral side to calculate uptake ratios. The final diagnosis was reached by pathologic findings in 17 patients and clinical and/or MR follow-up in 19 patients. Of the 36 patients, 11 had brain lymphoma, 1 glioblastoma multiforme, 15 toxoplasmosis and 9 other benign CNS lesions. Correlation between SPET and the final diagnosis revealed in 10 true-positive, 23 true-negative, 1 false-positive and 2 false-negative studies. All patients with toxoplasmosis had negative scans. A patient with a purulent infection had positive scans. Tl and sestamibi scans were concordant in every lesion. The same lesions that took up Tl were also visualized with sestamibi. However, sestamibi scans showed higher lesion-to-normal tissue uptake ratios (3.7{+-}1.8) compared with those of Tl (2.3{+-}0.8, P<0.002). Simultaneous acquisition of Tl and sestamibi can help differentiate CNS lymphoma from benign brain lesions in AIDS patients. (orig.) With 2 figs., 2 tabs., 34 refs.

  10. Subtraction Radiography for the Diagnosis of Bone Lesions in Dogs.

    Science.gov (United States)

    1984-05-31

    Avail ander Journal of Periodontology Dist Special Ř 211 East Chicago Avenue Room 924 Chicago, IL 60611 Dear Sirs: I m submitting an original...research article titled "Subtraction Radiography for the Diagnosis of Bone Lesions in Dogs" solely to the Journal of Periodontology for review and... clinical practice in our area. 60-70 Kvp would have produced more contrast in the radiographic films used for the conventional technique, but likely

  11. Value of Subtraction in Fat-Saturated Three-Dimensional Contrast-Enhanced Magnetic Resonance Angiography of the Hemodialysis Fistula

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, N.; Sato, M.; Niitsu, M.; Saida, Y. [Univ. of Tsukuba Hospital, Ibaraki (Japan). Dept. of Radiology

    2004-10-01

    Purpose: To evaluate image subtraction in a three-dimensional contrast-enhanced magnetic resonance angiography (3D CE-MRA) using fat suppression for the hemodialysis fistula. Material and Methods: Fifteen patients suffering from hemodialysis fistula dysfunction were imaged with 3D CE-MRA using fat suppression and digital subtraction angiography (DSA). Non-subtracted and subtracted MRA images using maximum intensity projection (MIP) were constructed and the validity of the MRA interpretations of the degree of vascular stenoses was evaluated using DSA as the standard of reference. Image quality was assessed using qualitative analysis (vessel contrast) and quantitative analysis (contrast-to-noise ratio (CNR) of the vessel versus the background). Results: In the vessels with stenosis of 50% or greater, the sensitivity and specificity of the non-subtracted MRA were 89.5% and 81.8%, respectively, and of the subtracted MRA 89.5% and 86.4%, respectively. There was no significant difference in the detectability of stenoses between either MRA. The vessel contrast of the anterior interosseous artery and the CNR of the anterior interosseous artery versus the background on the subtracted MRA were significantly superior to those on the non-subtracted MRA. With regard to the radial artery and cephalic vein, there was no significant difference in the vessel contrast and CNR between either MRA. Conclusion: Both subtracted and non-subtracted MRA techniques are useful in detecting hemodialysis fistula dysfunction.

  12. Identification of the nitrate contamination sources of the Brusselian sands groundwater body (Belgium) using a dual-isotope approach.

    Science.gov (United States)

    Mattern, Samuel; Sebilo, Mathieu; Vanclooster, Marnik

    2011-09-01

    Isotopic fingerprinting is an advanced technique allowing the classification of the nitrate source pollution of groundwater, but needs further development and validation. In this study, we performed measurements of natural stable isotopic composition of nitrate ((15)N and (18)O) in the groundwater body of the Brussels sands (Belgium) and studied the spatial and temporal dynamics of the isotope signature of this aquifer. Potential nitrogen sources sampled in the region had isotopic signatures that fell within the corresponding typical ranges found in the literature. For a few monitoring stations, the isotopic data strongly suggest that the sources of nitrate are from mineral fertiliser origin, as used in agriculture and golf courses. Other stations suggest that manure leaching from unprotected stockpiles in farms, domestic gardening practices, septic tanks and probably cemeteries contribute to the nitrate pollution of this groundwater body. For most monitoring stations, nitrate originates from a mixing of several nitrogen sources. The isotopic signature of the groundwater body was poorly structured in space, but exhibited a clear temporal structure. This temporal structure could be explained by groundwater recharge dynamics and cycling process of nitrogen in the soil-nitrogen pool.

  13. Ischemic ''memory image'' in acute myocardial infarction of {sup 123}I-BMIPP after reperfusion therapy. A comparison with {sup 99m}Tc-pyrophosphate and {sup 201}Tl dual-isotope SPECT

    Energy Technology Data Exchange (ETDEWEB)

    Mochizuki, Teruhito; Miyagawa, Masao; Sugawara, Yoshifumi; Kikuchi, Takanori; Ikezoe, Junpei [Ehime Univ., Matsuyama (Japan). School of Medicine; Murase, Kenya [Osaka Univ., Suita (Japan). Medical School; Higashino, Hiroshi [Ehime Imabari Hospital (Japan)

    2002-12-01

    Ischemic ''memory image'' is a phenomenon of {sup 123}I-15-(p-iodophenyl)-3-(R,S)-methylpentadecanoic acid (BMIPP) in which an area at risk of acute myocardial infarction (AMI), could be detected as a defect in a couple of weeks even after successful reperfusion therapy. The purpose of this study was to clarify the incidence of the ischemic ''memory image'' of {sup 123}I-BMIPP in patients with AMI by comparing {sup 99m}Tc-pyrophosphate(PYP) and {sup 201}Tl dual-isotope SPECT. Materials consisted of 14 patients with successfully reperfused AMI and 20 patients with old myocardial infarction (OMI). All AMI patients underwent PYP/Tl dual-isotope SPECT within 1 week after the onset of AMI, and BMIPP SPECT was performed within 1 week after the PYP/Tl dual-isotope SPECT. The extent and severity of the defect of BMIPP and Tl were visually scored into four grades: 0=no defect to 3=large or severe defect. These scores were compared. PYP positive AMI lesions were concordant with BMIPP defects (13/14). In AMI, both the extent and severity scores of BMIPP were higher than {sup 201}Tl (p<0.001). Differences (BMIPP-Tl) of extent and severity scores were greater in AMI than in OMI (p<0.001). In conclusion, the ischemic ''memory image'' obtained by means of the BMIPP is a common phenomenon (13/14) in AMI, and helpful in evaluating the area at risk. (author)

  14. Integrated characterization of natural attenuation of a PCE plume after thermal remediation of the source zone - incl. dual isotope and microbial techniques

    DEFF Research Database (Denmark)

    Broholm, Mette Martina

    PCE DNAPL contamination at the former central dry cleaning facility in Rødekro, Denmark, was subject to thermal (steam) source zone remediation in late 2006. A > 2 km long plume of chlorinated ethenes (PCE and chlorinated degradation products) which has migrated downgradient from the source zone...

  15. Spinal pedicle subtraction osteotomy for fixed sagittal imbalance patients.

    Science.gov (United States)

    Hyun, Seung-Jae; Kim, Yongjung J; Rhim, Seung-Chul

    2013-11-16

    In addressing spinal sagittal imbalance through a posterior approach, the surgeon now may choose from among a variety of osteotomy techniques. Posterior column osteotomies such as the facetectomy or Ponte or Smith-Petersen osteotomy provide the least correction, but can be used at multiple levels with minimal blood loss and a lower operative risk. Pedicle subtraction osteotomies provide nearly 3 times the per-level correction of Ponte/Smith-Petersen osteotomies; however, they carry increased technical demands, longer operative time, and greater blood loss and associated significant morbidity, including neurological injury. The literature focusing on pedicle subtraction osteotomy for fixed sagittal imbalance patients is reviewed. The long-term overall outcomes, surgical tips to reduce the complications and suggestions for their proper application are also provided.

  16. Polynomial Subtraction Method for Disconnected Quark Loops

    CERN Document Server

    Liu, Quan; Morgan, Ron

    2014-01-01

    The polynomial subtraction method, a new numerical approach for reducing the noise variance of Lattice QCD disconnected matrix elements calculation, is introduced in this paper. We use the MinRes polynomial expansion of the QCD matrix as the approximation to the matrix inverse and get a significant reduction in the variance calculation. We compare our results with that of the perturbative subtraction and find that the new strategy yields a faster decrease in variance which increases with quark mass.

  17. A Mathematical Model for Suppression Subtractive Hybridization

    OpenAIRE

    2002-01-01

    Suppression subtractive hybridization (SSH) is frequently used to unearth differentially expressed genes on a whole-genome scale. Its versatility is based on combining cDNA library subtraction and normalization, which allows the isolation of sequences of varying degrees of abundance and differential expression. SSH is a complex process with many adjustable parameters that affect the outcome of gene isolation.We present a mathematical model of SSH based on DNA hybridization kinetics for assess...

  18. Adaptive multiple subtraction with wavelet-based complex unary Wiener filters

    CERN Document Server

    Ventosa, Sergi; Huard, Irène; Pica, Antonio; Rabeson, Hérald; Ricarte, Patrice; Duval, Laurent

    2011-01-01

    Multiple attenuation is a crucial task in seismic data processing because multiples usually cover primaries from fundamental reflectors. Predictive multiple suppression methods remove these multiples by building an adapted model, aiming at being subtracted from the original signal. However, before the subtraction is applied, a matching filter is required to minimize amplitude differences and misalignments between actual multiples and their prediction, and thus to minimize multiples in the input dataset after the subtraction. In this work we focus on the subtraction element. We propose an adaptive multiple removal technique in a 1-D complex wavelet frame combined with a non-stationary adaptation performed via single-sample (unary) Wiener filters, consistently estimated on overlapping windows in the transformed domain. This approach greatly simplifies the matching filter estimation and, despite its simplicity, compares promisingly with standard adaptive 2-D methods, both in terms of results and retained speed a...

  19. The Spectrum of Static Subtracted Geometries

    CERN Document Server

    Andrade, Tomas; Cohen-Maldonado, Diego

    2016-01-01

    Subtracted geometries are black hole solutions of the four dimensional STU model with rather interesting ties to asymptotically flat black holes. In addition, a peculiar feature is that the solutions to the Klein-Gordon equation on this subtracted background can be organized according to representations of the conformal group $SO(2,2)$. We test if this behavior persists for the linearized fluctuations of gravitational and matter fields on static, electrically charged backgrounds of this kind. We find that there is a subsector of the modes that do display conformal symmetry, while some modes do not. We also discuss two different effective actions that describe these subtracted geometries and how the spectrum of quasinormal modes is dramatically different depending upon the action used.

  20. The groundwater nitrate isotope quandary: Is the dual isotopic composition of groundwater nitrate a recorder of interactions between N and Fe in the subsurface?

    Science.gov (United States)

    Wankel, S. D.; Hansel, C. M.; Tang, Y.; Johnston, D. T.

    2012-12-01

    Recent work continues to reveal the existence of new metabolic processes, novel elemental interactions and unique microbial groups that play potentially central roles in governing the global N cycle. These findings emphasize large gaps in our comprehensive understanding including which processes control ecosystem N loss and emission, how interactions among functional N cycling communities and other elemental cycles are structured, and how these processes and communities are affected by both natural and anthropogenic change. Among these recent advances, evidence for an intimate coupling of microbial N and Fe cycling is mounting. Here we explore N - Fe interactions in the terrestrial subsurface, by examining reactions between NO3- and Fe(II) and their influence on the dual isotopic composition (δ15N and δ18O) of NO3-. Specifically, there is a fundamental discrepancy of coupled O and N isotope effects (18ɛ:15ɛ) between culture-based isotopic studies of denitrifying bacteria and field-based isotopic measurements of groundwater NO3- loss under anaerobic conditions (having been interpreted as denitrification). We suggest this discrepancy may be the result of a ubiquitous, yet largely unrecognized, coupling of abiotic and/or biotic Fe cycling with both reductive and anaerobic oxidative N cycling pathways and present preliminary data in support of this hypothesis. Experimental data show substantial abiotic reduction of NO3- by Fe(II). Though kinetically slow, the presence of metals such as Cu greatly increased rates, although were not required for abiotic NO3- reduction by Fe(II). Kinetic isotope effects for N (15ɛ) and O (18ɛ) during NO3- reduction (with and without catalyst) varied widely across experimental conditions and was influenced by the interaction of Fe(II) with mineral surfaces. The magnitude of 15ɛ, 18ɛ and 18ɛ:15ɛ did not appear to be related to reduction rate. Values of 15ɛ always exceeded 18ɛ (18ɛ:15ɛ = 0.48 to 0.71), which are consistent with

  1. Probabilistic Model-Based Background Subtraction

    DEFF Research Database (Denmark)

    Krüger, Volker; Andersen, Jakob; Prehn, Thomas

    2005-01-01

    manner. Bayesian propagation over time is used for proper model selection and tracking during model-based background subtraction. Bayes propagation is attractive in our application as it allows to deal with uncertainties during tracking. We have tested our approach on suitable outdoor video data....... is the correlation between pixels. In this paper we introduce a model-based background subtraction approach which facilitates prior knowledge of pixel correlations for clearer and better results. Model knowledge is being learned from good training video data, the data is stored for fast access in a hierarchical...

  2. Construction of Differential-Methylation Subtractive Library

    Directory of Open Access Journals (Sweden)

    Wei Hu

    2014-01-01

    Full Text Available Stress-induced ROS changes DNA methylation patterns. A protocol combining methylation-sensitive restriction endonuclease (MS-RE digestion with suppression subtractive hybridization (SSH to construct the differential-methylation subtractive library was developed for finding genes regulated by methylation mechanism under cold stress. The total efficiency of target fragment detection was 74.64%. DNA methylation analysis demonstrated the methylation status of target fragments changed after low temperature or DNA methyltransferase inhibitor treatment. Transcription level analysis indicated that demethylation of DNA promotes gene expression level. The results proved that our protocol was reliable and efficient to obtain gene fragments in differential-methylation status.

  3. Renormalizing the NN interaction with multiple subtractions

    Energy Technology Data Exchange (ETDEWEB)

    Timoteo, V.S. [Faculdade de Tecnologia, Universidade Estadual de Campinas, 13484-332 Limeira, SP (Brazil); Frederico, T. [Instituto Tecnologico de Aeronautica, Comando de Tecnologia Aeroespacial, 12228-900 Sao Jose dos Campos, SP (Brazil); Delfino, A. [Departamento de Fisica, Universidade Federal Fluminense, 24210-150 Niteroi, RJ (Brazil); Tomio, L. [Instituto de Fisica Teorica, Universidade Estadual Paulista, 01140-070 Sao Paulo, SP (Brazil); Szpigel, S.; Duraes, F.O. [Centro de Ciencias e Humanidades, Universidade Presbiteriana Mackenzie, 01302-907 Sao Paulo, SP (Brazil)

    2010-02-15

    The aim of this work is to show how to renormalize the nucleon-nucleon interaction at next-to-next-to-leading order using a systematic subtractive renormalization approach with multiple subtractions. As an example, we calculate the phase shifts for the partial waves with total angular momentum J=2. The intermediate driving terms at each recursive step as well as the renormalized T-matrix are also shown. We conclude that our method is reliable for singular potentials such as the two-pion exchange and derivative contact interactions.

  4. Digital subtraction angiography and intraarterial contrast medium injection for coronary examinations

    Energy Technology Data Exchange (ETDEWEB)

    Tobio, R.; Kallmeyer, C.; Castello, J.

    1985-01-01

    Digital subtraction angiography (DSA) is an established method of vasography, most extensively used as i.v. DSA. Intraarterial injection, however, applying selective or non-selective contrast medium injection, seems to be at least as important a technique although it has not yet met with corresponding interest. The article explains advantages of the technique for angiographic examinations, in particular of coronary angiography.

  5. Digital subtraction angiography in head and neck radiology

    Energy Technology Data Exchange (ETDEWEB)

    Carmody, R.F.; Seeger, J.F.; Smith, R.L.; Horsley, W.W.; Miller, R.W.

    1984-07-01

    Intravenous digital subtraction angiography (IVDSA) was used to evaluate 44 patients with suspected otolaryngologic abnormalities. Sixteen had IVDSA for pulsatile tinnitus or suspected glomus tumor of the petrous bone. Nine patients were evaluated because of pulsatile neck masses, and 12 others had suspected tumors of the neck, face, and paranasal sinuses. Seven had IVDSA following head and neck trauma. The technique of examination is described. The current indications of IVDSA in head and neck radiology are discussed. It is concluded that IVDSA is a suitable substitute for conventional angiography for many otolaryngologic conditions and, because of its safety, can be used more liberally.

  6. [Ziedses des Plantes: inventor of planigraphy and subtraction].

    Science.gov (United States)

    van Gijn, Jan; Gijselhart, Joost P

    2011-01-01

    Bernard George Ziedses des Plantes (1902-1993) trained in Utrecht, the Netherlands, as specialist in nervous diseases, but his lifelong passion was to improve X-ray imaging of living tissues. In the 1930s he not only built the first machine for planigraphy, in which the X-ray tube and the film moved together around the plane of interest, but he also designed the subtraction method to improve images after injection of contrast agents. Eventually a full-time radiologist, he also developed the 'somersault' technique of ventriculography and pioneered isotope scintigraphy.

  7. Temporal subtraction contrast-enhanced dedicated breast CT

    Science.gov (United States)

    Gazi, Peymon M.; Aminololama-Shakeri, Shadi; Yang, Kai; Boone, John M.

    2016-09-01

    implemented using a parallel processing architecture resulting in rapid execution time for the iterative segmentation and intensity-adaptive registration techniques. Characterization of contrast-enhanced lesions is improved using temporal subtraction contrast-enhanced dedicated breast CT. Adaptation of Demons registration forces as a function of contrast-enhancement levels provided a means to accurately align breast tissue in pre- and post-contrast image acquisitions, improving subtraction results. Spatial subtraction of the aligned images yields useful diagnostic information with respect to enhanced lesion morphology and uptake.

  8. Diagnosis of Subtraction Bugs Using Bayesian Networks

    Science.gov (United States)

    Lee, Jihyun; Corter, James E.

    2011-01-01

    Diagnosis of misconceptions or "bugs" in procedural skills is difficult because of their unstable nature. This study addresses this problem by proposing and evaluating a probability-based approach to the diagnosis of bugs in children's multicolumn subtraction performance using Bayesian networks. This approach assumes a causal network relating…

  9. Polygon Subtraction in 2 or 3 Dimensions

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, John E.

    2013-10-01

    When searching for computer code to perform the ubiquitous task of subtracting one polygon from another, it is difficult to find real examples and detailed explanations. This paper outlines the step-by-step process necessary to accomplish this basic task.

  10. Robust Background Subtraction with Incremental Eigen Models

    NARCIS (Netherlands)

    Gritti, T.

    2008-01-01

    In this report we first describe a background subtraction algorithm based on the use of eigen space decomposition. We then present a method to achive incremental modelling, which allows for faster computation and saving in memory requirements. We discuss the performanceof the algorithm and the issu

  11. Children's Understanding of Addition and Subtraction Concepts

    Science.gov (United States)

    Robinson, Katherine M.; Dube, Adam K.

    2009-01-01

    After the onset of formal schooling, little is known about the development of children's understanding of the arithmetic concepts of inversion and associativity. On problems of the form a+b-b (e.g., 3+26-26), if children understand the inversion concept (i.e., that addition and subtraction are inverse operations), then no calculations are needed…

  12. Video Background Subtraction in Complex Environments

    Directory of Open Access Journals (Sweden)

    Juana E. Santoyo-Morales

    2014-06-01

    Full Text Available Background subtraction models based on mixture of Gaussians have been extensively used for detecting objects in motion in a wide variety of computer vision applications. However, background subtraction modeling is still an open problem particularly in video scenes with drastic illumination changes and dynamic backgrounds (complex backgrounds. The purpose of the present work is focused on increasing the robustness of background subtraction models to complex environments. For this, we proposed the following enhancements: a redefine the model distribution parameters involved in the detection of moving objects (distribution weight, mean and variance, b improve pixel classification (background/foreground and variable update mechanism by a new time-space dependent learning-rate parameter, and c replace the pixel-based modeling currently used in the literature by a new space-time region-based model that eliminates the noise effect caused by drastic changes in illumination. Our proposed scheme can be implemented on any state of the art background subtraction scheme based on mixture of Gaussians to improve its resilient to complex backgrounds. Experimental results show excellent noise removal and object motion detection properties under complex environments.

  13. Rod strain after pedicle subtraction osteotomy

    DEFF Research Database (Denmark)

    Gehrchen, Poul Martin; Hallager, Dennis Winge; Dahl, Benny

    2016-01-01

    Pedicle subtraction osteotomy (PSO) can provide major sagittal correction for adult spinal deformity, sometimes achieving correction greater than 308. Surgeons have reported failure rates up to 30% within 2 years, increasing to 46% after 4 to 5 years (SDC Figure 1, http://links.lww.com/BRS/B87). ...

  14. Intensity Weighted Subtraction Microscopy Approach for Image Contrast and Resolution Enhancement

    Science.gov (United States)

    Korobchevskaya, Kseniya; Peres, Chiara; Li, Zhibin; Antipov, Alexei; Sheppard, Colin J. R.; Diaspro, Alberto; Bianchini, Paolo

    2016-05-01

    We propose and demonstrate a novel subtraction microscopy algorithm, exploiting fluorescence emission difference or switching laser mode and their derivatives for image enhancement. The key novelty of the proposed approach lies in the weighted subtraction coefficient, adjusted pixel-by-pixel with respect to the intensity distributions of initial images. This method produces significant resolution enhancement and minimizes image distortions. Our theoretical and experimental studies demonstrate that this approach can be applied to any optical microscopy techniques, including label free and non-linear methods, where common super-resolution techniques cannot be used.

  15. Real-time optical image subtraction by a holographic shear lens

    Science.gov (United States)

    Rao, V. Venkateswara; Joenathan, C.; Sirohi, R. S.

    1985-08-01

    A new optical method of image subtraction by employing a holographic shear lens is proposed. The principle underlying this technique is that of optical interference between two sheared fields produced by the holographic shear lens (HSL). Two dissimilar inputs with some common characters are subtracted in real time while keeping the HSL at the Fourier plane of a well corrected lens. The difference is detectable only when zero fringe is obtained in the interferogram. Experimental verification is presented with the results. The basic advantages of this technique are the simplicity in aligning the input transparencies and the real time operation.

  16. Procedures for imaging of hemodialysis fistulas with particular reference to digital subtraction angiography (DSA)

    Energy Technology Data Exchange (ETDEWEB)

    Neufang, K.F.R.; Erasmi-Koerber, H.; Wimmer, G.

    1983-05-01

    All angiographic procedures established for imaging of hemodialysis fistulas, such as direct venous angiography, intravenous subtraction angiography and arteriography by direct puncture of the brachial artery by Seldinger's transfemoral technique, can also be effected with digital image processing. Depending on the angiographic technique, the use of digital subtraction angiography has several advantages: lower doses and concentrations of the contrast agent, lower risk of complications (thrombosis of the fistula, vasospasm) and freedom from pain. In addition, there is a marked reduction of examination time and film cost.

  17. Impaired coronary flow reserve is the most important marker of viable myocardium in the myocardial segment-based analysis of dual-isotope gated myocardial perfusion single-photon emission computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Won Woo [Dept. of Nuclear Medicine, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam (Korea, Republic of); So, Young [Dept. of Nuclear Medicine, Konkuk University School of Medicine, Seoul (Korea, Republic of); Kim, Ki Bong; Lee, Dong Soo [Seoul National University Hospital, Seoul National University College of Medicine, Seoul (Korea, Republic of)

    2014-04-15

    The aim of this study was to investigate the most robust predictor of myocardial viability among stress/rest reversibility (coronary flow reserve [CFR] impairment), {sup 201}Tl perfusion status at rest, {sup 201}Tl 24 hours redistribution and systolic wall thickening of {sup 99m}Tc-methoxyisobutylisonitrile using a dual isotope gated myocardial perfusion single-photon emission computed tomography (SPECT) in patients with coronary artery disease (CAD) who were re-vascularized with a coronary artery bypass graft (CABG) surgery. A total of 39 patients with CAD was enrolled (34 men and 5 women), aged between 36 and 72 years (mean 58 ± 8 standard in years) who underwent both pre- and 3 months post-CABG myocardial SPECT. We analyzed 17 myocardial segments per patient. Perfusion status and wall motion were semi-quantitatively evaluated using a 4-point grading system. Viable myocardium was defined as dysfunctional myocardium which showed wall motion improvement after CABG. The left ventricular ejection fraction (LVEF) significantly increased from 37.8 ± 9.0% to 45.5 ± 12.3% (p < 0.001) in 22 patients who had a pre-CABG LVEF lower than 50%. Among 590 myocardial segments in the re-vascularized area, 115 showed abnormal wall motion before CABG and 73.9% (85 of 115) had wall motion improvement after CABG. In the univariate analysis (n = 115 segments), stress/rest reversibility (p < 0.001) and {sup 201}Tl rest perfusion status (p = 0.024) were significant predictors of wall motion improvement. However, in multiple logistic regression analysis, stress/rest reversibility alone was a significant predictor for post-CABG wall motion improvement (p < 0.001). Stress/rest reversibility (impaired CFR) during dual-isotope gated myocardial perfusion SPECT was the single most important predictor of wall motion improvement after CABG.

  18. 应用抑制性消减杂交技术筛选转化生长因子β1刺激LX02细胞的反式调节基因%Screening and cloning genes transactivated by TGF beta 1 in hepatic stellate cells using suppression subtractive hybridization technique

    Institute of Scientific and Technical Information of China (English)

    肖琳; 张跃新; 张建龙; 李燕; 成军; 郭江; 张黎颖; 洪源; 伦永志; 蓝贤勇; 武会娟; 张丽娟

    2008-01-01

    目的 构建转化生长因子(TGF)β1刺激大鼠肝星状细胞(LX02)反式调节基因的cDNA消减文库,筛选并克隆TGF β1反式调节相关基因,以阐明TGF β1介导肝纤维化的分子生物学机制.方法 以TGF β1刺激LX02细胞,同时以磷酸盐缓冲液刺激的LX02细胞作为对照.提取mRNA并逆转录为cDNA,经Rsa Ⅰ酶切后,将实验组cDNA分成两组,分别与两种不同的接头衔接,再与对照组cDNA进行两次消减杂交及两次抑制性多聚酶链反应.将产物与pGEM-Teasy载体连接,构建cDNA消减文库,并转染大肠杆菌进行文库扩增;随机挑选克隆经PCR扩增后进行测序及同源性分析. 结果成功构建了TGF β1刺激LX02细胞反式调节基因的cDNA消减文库.文库扩增后得到146个200~1000bp插入片段的阳性克隆;随机挑取其中35个克隆进行测序,30个列序成功,并通过生物信息学分析发现有28个与已知基因序列和2个与未知功能基因序列高度同源.结论 应用抑制性消减杂交技术成功构建了TGF β1刺激LX02细胞反式调节基因的cDNA消减文库,筛选到一些与细胞生长调节、蛋白质合成,信号传导、细胞外基质代谢、扰脂质过氧化等密切相关的蛋白质编码基因,为进一步阐明TGF β1介导肝纤维化的分子生物学机制提供了线索.%Objectives To construct a eDNA subtractive library of genes transactivated by TGF beta 1 in LX02 hepatic stellate cells (HSC); to screen and to clone the regulated genes transactivated by TGF beta 1; and to elucidate the molecular biological mechanism of hepatic fibrosis mediated by TGF beta 1. Methods mRNA was isolated from HSC treated with TGF beta 1 or with PBS (as controls). Suppression subtractive hybridization (SSH) technique was employed to analyze the differentially expressed DNA sequence between the two groups. After restriction enzyme Rsa I digestion, small size cDNAs were obtained. Then tester cDNA was divided into two groups and ligated

  19. Motion Tracking with Fast Adaptive Background Subtraction

    Institute of Scientific and Technical Information of China (English)

    Xiao; De-Gui; Yu; Sheng-sheng; 等

    2003-01-01

    To extract and track moving objects is usually one of the most important tasks of intelligent video surveillance systems. This paper presents a fast and adaptive background subtraction algorithm and the motion tracking process using this algorithm. The algorithm uses only luminance components of sampled image sequence pixels and models every pixel in a statistical model.The algorithm is characterized by its ability of real time detecting sudden lighting changes, and extracting and tracking motion objects faster. It is shown that our algorithm can be realized with lower time and space complexity and adjustable object detection error rate with comparison to other background subtraction algorithms. Making use of the algorithm, an indoor monitoring system is also worked out and the motion tracking process is presented in this paper.Experimental results testify the algorithms' good performances when used in an indoor monitoring system.

  20. Interferometry with Photon-Subtracted Thermal Light

    CERN Document Server

    Rafsanjani, Seyed Mohammad Hashemi; Magana-Loaiza, Omar S; Gard, Bryan T; Birrittella, Richard; Koltenbah, B E; Parazzoli, C G; Capron, Barbara A; Gerry, Christopher C; Dowling, Jonathan P; Boyd, Robert W

    2016-01-01

    We propose and implement a quantum procedure for enhancing the sensitivity with which one can determine the phase shift experienced by a weak light beam possessing thermal statistics in passing through an interferometer. Our procedure entails subtracting exactly one (which can be generalized to m) photons from the light field exiting an interferometer containing a phase-shifting element in one of its arms. As a consequence of the process of photon subtraction, and somewhat surprisingly, the mean photon number and signal-to-noise ratio of the resulting light field are thereby increased, leading to enhanced interferometry. This method can be used to increase measurement sensitivity in a variety of practical applications, including that of forming the image of an object illuminated only by weak thermal light.

  1. Moving object detection using background subtraction

    CERN Document Server

    Shaikh, Soharab Hossain; Chaki, Nabendu

    2014-01-01

    This Springer Brief presents a comprehensive survey of the existing methodologies of background subtraction methods. It presents a framework for quantitative performance evaluation of different approaches and summarizes the public databases available for research purposes. This well-known methodology has applications in moving object detection from video captured with a stationery camera, separating foreground and background objects and object classification and recognition. The authors identify common challenges faced by researchers including gradual or sudden illumination change, dynamic bac

  2. Subtractive Structural Modification of Morpho Butterfly Wings.

    Science.gov (United States)

    Shen, Qingchen; He, Jiaqing; Ni, Mengtian; Song, Chengyi; Zhou, Lingye; Hu, Hang; Zhang, Ruoxi; Luo, Zhen; Wang, Ge; Tao, Peng; Deng, Tao; Shang, Wen

    2015-11-11

    Different from studies of butterfly wings through additive modification, this work for the first time studies the property change of butterfly wings through subtractive modification using oxygen plasma etching. The controlled modification of butterfly wings through such subtractive process results in gradual change of the optical properties, and helps the further understanding of structural optimization through natural evolution. The brilliant color of Morpho butterfly wings is originated from the hierarchical nanostructure on the wing scales. Such nanoarchitecture has attracted a lot of research effort, including the study of its optical properties, its potential use in sensing and infrared imaging, and also the use of such structure as template for the fabrication of high-performance photocatalytic materials. The controlled subtractive processes provide a new path to modify such nanoarchitecture and its optical property. Distinct from previous studies on the optical property of the Morpho wing structure, this study provides additional experimental evidence for the origination of the optical property of the natural butterfly wing scales. The study also offers a facile approach to generate new 3D nanostructures using butterfly wings as the templates and may lead to simpler structure models for large-scale man-made structures than those offered by original butterfly wings.

  3. Nonenhanced magnetic resonance angiography (MRA) of the calf arteries at 3 Tesla: intraindividual comparison of 3D flow-dependent subtractive MRA and 2D flow-independent non-subtractive MRA.

    Science.gov (United States)

    Knobloch, Gesine; Lauff, Marie-Teres; Hirsch, Sebastian; Schwenke, Carsten; Hamm, Bernd; Wagner, Moritz

    2016-12-01

    To prospectively compare 3D flow-dependent subtractive MRA vs. 2D flow-independent non-subtractive MRA for assessment of the calf arteries at 3 Tesla. Forty-two patients with peripheral arterial occlusive disease underwent nonenhanced MRA of calf arteries at 3 Tesla with 3D flow-dependent subtractive MRA (fast spin echo sequence; 3D-FSE-MRA) and 2D flow-independent non-subtractive MRA (balanced steady-state-free-precession sequence; 2D-bSSFP-MRA). Moreover, all patients underwent contrast-enhanced MRA (CE-MRA) as standard-of-reference. Two readers performed a per-segment evaluation for image quality (4 = excellent to 0 = non-diagnostic) and severity of stenosis. Image quality scores of 2D-bSSFP-MRA were significantly higher compared to 3D-FSE-MRA (medians across readers: 4 vs. 3; p Tesla with significantly higher image quality and diagnostic accuracy compared to 3D flow-dependent subtractive MRA (3D-FSE-MRA). • 2D flow-independent non-subtractive MRA (2D-bSSFP-MRA) is a robust NE-MRA technique at 3T • 2D-bSSFP-MRA outperforms 3D flow-dependent subtractive MRA (3D-FSE-MRA) as NE-MRA of calf arteries • 2D-bSSFP-MRA is a promising alternative to CE-MRA for calf PAOD evaluation.

  4. Background Subtraction Based on Three-Dimensional Discrete Wavelet Transform.

    Science.gov (United States)

    Han, Guang; Wang, Jinkuan; Cai, Xi

    2016-03-30

    Background subtraction without a separate training phase has become a critical task, because a sufficiently long and clean training sequence is usually unavailable, and people generally thirst for immediate detection results from the first frame of a video. Without a training phase, we propose a background subtraction method based on three-dimensional (3D) discrete wavelet transform (DWT). Static backgrounds with few variations along the time axis are characterized by intensity temporal consistency in the 3D space-time domain and, hence, correspond to low-frequency components in the 3D frequency domain. Enlightened by this, we eliminate low-frequency components that correspond to static backgrounds using the 3D DWT in order to extract moving objects. Owing to the multiscale analysis property of the 3D DWT, the elimination of low-frequency components in sub-bands of the 3D DWT is equivalent to performing a pyramidal 3D filter. This 3D filter brings advantages to our method in reserving the inner parts of detected objects and reducing the ringing around object boundaries. Moreover, we make use of wavelet shrinkage to remove disturbance of intensity temporal consistency and introduce an adaptive threshold based on the entropy of the histogram to obtain optimal detection results. Experimental results show that our method works effectively in situations lacking training opportunities and outperforms several popular techniques.

  5. Comprehensive Study and Comparative Analysis of Different Types of Background Sub-traction Algorithms

    Directory of Open Access Journals (Sweden)

    Priyank Shah

    2014-07-01

    Full Text Available There are many methods proposed for Back-ground Subtraction algorithm in past years. Background subtraction algorithm is widely used for real time moving object detection in video surveillance system. In this paper we have studied and implemented different types of meth-ods used for segmentation in Background subtraction algo-rithm with static camera. This paper gives good under-standing about procedure to obtain foreground using exist-ing common methods of Background Subtraction, their complexity, utility and also provide basics which will useful to improve performance in the future . First, we have explained the basic steps and procedure used in vision based moving object detection. Then, we have debriefed the common methods of background subtraction like Sim-ple method, statistical methods like Mean and Median filter, Frame Differencing and W4 System method, Running Gaussian Average and Gaussian Mixture Model and last is Eigenbackground Model. After that we have implemented all the above techniques on MATLAB software and show some experimental results for the same and compare them in terms of speed and complexity criteria.

  6. Automated contralateral subtraction of dental panoramic radiographs for detecting abnormalities in paranasal sinus

    Science.gov (United States)

    Hara, Takeshi; Mori, Shintaro; Kaneda, Takashi; Hayashi, Tatsuro; Katsumata, Akitoshi; Fujita, Hiroshi

    2011-03-01

    Inflammation in the paranasal sinus is often observed in seasonal allergic rhinitis or with colds, but is also an indication for odontogenic tumors, carcinoma of the maxillary sinus or a maxillary cyst. The detection of those findings in dental panoramic radiographs is not difficult for radiologists, but general dentists may miss the findings since they focus on treatments of teeth. The purpose of this work is to develop a contralateral subtraction method for detecting the odontogenic sinusitis region on dental panoramic radiographs. We developed a contralateral subtraction technique in paranasal sinus region, consisting of 1) image filtering of the smoothing and sobel operation for noise reduction and edge extraction, 2) image registration of mirrored image by using mutual information, and 3) image display method of subtracted pixel data. We employed 56 cases (24 normal and 32 abnormal). The abnormal regions and the normal cases were verified by a board-certified radiologist using CT scans. Observer studies with and without subtraction images were performed for 9 readers. The true-positive rate at a 50% confidence level in 7 out of 9 readers was improved, but there was no statistical significance in the difference of area-under-curve (AUC) in each radiologist. In conclusion, the contralateral subtraction images of dental panoramic radiographs may improve the detection rate of abnormal regions in paranasal sinus.

  7. Subtraction of point sources from interferometric radio images through an algebraic forward modeling scheme

    CERN Document Server

    Bernardi, G; Ord, S M; Greenhill, L J; Pindor, B; Wayth, R B; Wyithe, J S B

    2010-01-01

    We present a method for subtracting point sources from interferometric radio images via forward modeling of the instrument response and involving an algebraic nonlinear minimization. The method is applied to simulated maps of the Murchison Wide-field Array but is generally useful in cases where only image data are available. After source subtraction, the residual maps have no statistical difference to the expected thermal noise distribution at all angular scales, indicating high effectiveness in the subtraction. Simulations indicate that the errors in recovering the source parameters decrease with increasing signal-to-noise ratio, which is consistent with the theoretical measurement errors. In applying the technique to simulated snapshot observations with the Murchison Wide-field Array, we found that all 101 sources present in the simulation were recovered with an average position error of 10 arcsec and an average flux density error of 0.15%. This led to a dynamic range increase of approximately 3 orders of m...

  8. Digital subtraction angiography of the thoracic aorta

    Energy Technology Data Exchange (ETDEWEB)

    Grossman, L.B.; Buonocore, E.; Modic, M.T.; Meaney, T.F.

    1984-02-01

    Forty-three patients with acquired and congenital abnormalities of the thoracic aorta were studied using digital subtraction angiography (DSA) after an intravenous bolus injection of 40 ml of contrast material. Abnormalities studied included coarctation, pseudocoarctation, Marfan syndrome, cervical aorta, double aortic arch, aneurysm, dissection, and tumor. Twenty-four patients also had conventional angiography. DSA was accurate in 95% of cases; in the other 5%, involving patients with acute type I dissection, the coronary arteries could not be seen. The authors concluded that in 92% of their patients, DSA could have replaced the standard aortogram.

  9. An analysis of the influence of background subtraction and quenching on jet observables in heavy-ion collisions

    CERN Document Server

    Apolinario, Liliana; Cunqueiro, Leticia

    2013-01-01

    Subtraction of the large background in reconstruction is a key ingredient in jet studies in high-energy heavy-ion collisions at RHIC and the LHC. Here we address the question to which extent the most commonly used subtraction techniques are able to eliminate the effects of the background on the most commonly discussed observables at present: single inclusive jet distributions, dijet asymmetry and azimuthal distributions. We consider two different background subtraction methods, an area-based one implemented through the FastJet pack- age and a pedestal subtraction method, that resemble the ones used by the experimental collaborations at the LHC. We also analyze different ways of defining the optimal parame- ters in the second method. We use a toy model that easily allows variations of the background characteristics: average background level and fluctuations and azimuthal structure, but cross- checks are also done with a Monte Carlo simulator. Furthermore, we consider the influence of quenching using Q-PYTHIA o...

  10. First determination of the heart-to-mediastinum ratio using cardiac dual isotope ({sup 123}I-MIBG/{sup 99m}Tc-tetrofosmin) CZT imaging in patients with heart failure: the ADRECARD study

    Energy Technology Data Exchange (ETDEWEB)

    Bellevre, Dimitri; Desmonts, Cedric [CHU Cote de Nacre, Department of Nuclear Medicine, Caen (France); Manrique, Alain; Agostini, Denis [CHU Cote de Nacre, Department of Nuclear Medicine, Caen (France); EA 4650, Normandie Universite, Caen (France); Legallois, Damien [EA 4650, Normandie Universite, Caen (France); CHU Cote de Nacre, Cardiology Department, Caen (France); Bross, Samy; Baavour, Rafael; Roth, Nathaniel [Spectrum Dynamics, Biosensors, Caesarea (Israel); Blaire, Tanguy; Bailliez, Alban [EA 4650, Normandie Universite, Caen (France); IRIS, Polyclinique du Bois, Nuclear Medicine Department, Lille (France)

    2015-11-15

    Cardiac innervation is assessed using the heart-to-mediastinum ratio (HMR) of metaiodobenzylguanidine (MIBG) on planar imaging using Anger single photon emission computed tomography (A-SPECT). The aim of the study was to determine the HMR of MIBG obtained using a CZT-based camera (D-SPECT; Spectrum Dynamics, Israel) in comparison with that obtained using conventional planar imaging. The ADRECARD study prospectively evaluated 44 patients with heart failure. They underwent planar acquisition using the A-SPECT camera 4 h after {sup 123}I-MIBG injection (236.4 ± 39.7 MBq). To localize the heart using D-SPECT, {sup 99m}Tc-tetrofosmin (753 ± 133 MBq) was administered and dual isotope acquisition was performed using the D-SPECT system. HMR was calculated using both planar A-SPECT imaging and front view D-SPECT cine data. In a phantom study, we estimated a model fitting the A-SPECT and the D-SPECT data that was further applied to correct for differences between the cameras. A total of 44 patients (39 men and 5 women, aged 60 ± 11 years) with ischaemic (31 patients) and nonischaemic (13 patients) cardiomyopathy completed the study. Most patients (28 of 44) were NYHA class II, and the mean left ventricular ejection fraction was 33 ± 7 %. The mean HMR values were 1.34 ± 0.15 and 1.45 ± 0.27 from A-SPECT and D-SPECT, respectively (p < 0.0001). After correction, Lin's concordance correlation showed an almost perfect concordance between corrected D-SPECT HMR and A-SPECT HMR, and Bland-Altman analysis demonstrated a high agreement between the two measurements. The ADRECARD study demonstrated that determination of late HMR during cardiac MIBG imaging using dual isotope ({sup 123}I and {sup 99m}Tc) acquisition on a CZT camera (D-SPECT) is feasible in patients with heart failure. A linear correction based on the phantom study yielded a high agreement between {sup 123}I MIBG HMR obtained using a CZT camera and that from conventional planar imaging. (orig.)

  11. Coherent bremsstrahlung used for digital subtraction angiography

    Science.gov (United States)

    Überall, Herbert

    2007-05-01

    Digital subtraction angiography (DSA), also known as Dichromography, using synchrotron radiation beams has been developed at Stanford University (R. Hofstadter) and was subsequently taken over at the Brookhaven Synchrotron and later at Hamburg (HASYLAB) [see, e.g., W.R. Dix, Physik in unserer Zeit. 30 (1999) 160]. The imaging of coronary arteries is carried out with an iodine-based contrast agent which need not be injected into the heart. The radiation must be monochromatized and is applied above and below the K-edge of iodine (33.16 keV), with a subsequent digital subtraction of the two images. Monochromatization of the synchrotron radiation causes a loss of intensity of 10 -3. We propose instead the use of coherent bremsstrahlung [see, e.g., A.W. Saenz and H. Uberall, Phys. Rev. B25 (1982) 448] which is inherently monochromatic, furnishing a flux of 10 12 photon/sec. This requires a 10-20 MeV electron linac which can be obtained by many larger hospitals, eliminating the scheduling problems present at synchrotrons. The large, broad incoherent bremsstrahlung background underlying the monochromatic spike would lead to inadmissible overexposure of the patient. This problem can be solved with the use of Kumakhov's capillary optics [see e.g., S.B.Dabagov, Physics-Uspekhi 46 (2003) 1053]: the low-energy spiked radiation can be deflected towards the patient, while the higher energy incoherent background continues forward, avoiding the patient who is placed several meters from the source.

  12. Parallel decompositions of Mueller matrices and polarimetric subtraction

    Directory of Open Access Journals (Sweden)

    Gil J.J.

    2010-06-01

    Full Text Available From a general formulation of the physically realizable parallel decompositions of the Mueller matrix M of a given depolarizing system, a procedure for determining the set of pure Mueller matrices susceptible to be subtracted from M is presented. This procedure provides a way to check if a given pure Mueller matrix N can be subtracted from M or not. If this check is positive, the value of the relative cross section of the subtracted component is also determined.

  13. Parallel decompositions of Mueller matrices and polarimetric subtraction

    OpenAIRE

    Gil J.J.

    2010-01-01

    From a general formulation of the physically realizable parallel decompositions of the Mueller matrix M of a given depolarizing system, a procedure for determining the set of pure Mueller matrices susceptible to be subtracted from M is presented. This procedure provides a way to check if a given pure Mueller matrix N can be subtracted from M or not. If this check is positive, the value of the relative cross section of the subtracted component is also determined.

  14. PSF subtraction to search for distant Jupiters with SPITZER

    Science.gov (United States)

    Rameau, Julien; Artigau, Etienne; Baron, Frédérique; Lafrenière, David; Doyon, Rene; Malo, Lison; Naud, Marie-Eve; Delorme, Philippe; Janson, Markus; Albert, Loic; Gagné, Jonathan; Beichman, Charles

    2015-12-01

    In the course of the search for extrasolar planets, a focus has been made towards rocky planets very close (within few AUs) to their parent stars. However, planetary systems might host gas giants as well, possibly at larger separation from the central star. Direct imaging is the only technique able to probe the outer part of planetary systems. With the advent of the new generation of planet finders like GPI and SPHERE, extrasolar systems are now studied at the solar system scale. Nevertheless, very extended planetary systems do exist and have been found (Gu Ps, AB Pic b, etc.). They are easier to detect and characterize. They are also excellent proxy for close-in gas giants that are detected from the ground. These planets have no equivalent in our solar system and their origin remain a matter of speculation. In this sense, studying planetary systems from its innermost to its outermost part is therefore mandatory to have a clear understanding of its architecture, hence hints of its formation and evolution. We are carrying out a space-based survey using SPITZER to search for distant companions around a well-characterized sample of 120 young and nearby stars. We designed an observing strategy that allows building a very homogeneous PSF library. With this library, we perform a PSF subtraction to search for planets from 10’’ down to 1’’. In this poster, I will present the library, the different algorithms used to subtract the PSF, and the promising detection sensitivity that we are able to reach with this survey. This project to search for the most extreme planetary systems is unique in the exoplanet community. It is also the only realistic mean of directly imaging and subsequently obtaining spectroscopy of young Saturn or Jupiter mass planets in the JWST-era.

  15. cDNA amplification by SMART-PCR and suppression subtractive hybridization (SSH)-PCR.

    Science.gov (United States)

    Hillmann, Andrew; Dunne, Eimear; Kenny, Dermot

    2009-01-01

    The comparison of two RNA populations that differ from the effects of a single-independent variable, such as a drug treatment or a specific genetic defect, can identify differences in the abundance of specific transcripts that vary in a population-dependent manner. There are a variety of methods for identifying differentially expressed genes, including microarray, SAGE, qRT-PCR, and DDGE. This protocol describes a potentially less sensitive yet relatively easy and cost-effective alternative that does not require prior knowledge of the transcriptomes under investigation and is particularly applicable when minimal levels of starting material, RNA, are available. RNA input can often be a limiting factor when analyzing RNA from, for example, rigorously purified blood cells. This protocol describes the use of SMART-PCR to amplify cDNA from sub-microgram levels of RNA. The amplified cDNA populations under comparison are then subjected to suppression subtractive hybridization (SSH-PCR), a technique that couples subtractive hybridization with suppression PCR to selectively amplify fragments of differentially expressed genes. The final products are cDNA populations enriched for significantly over-represented transcripts in either of the two input RNA preparations. These cDNA populations may then be cloned to make subtracted cDNA libraries and/or used as probes to screen subtracted cDNA, global cDNA, or genomic DNA libraries.

  16. Two-dimensional thick-slice MR digital subtraction angiography for assessment of cerebrovascular occlusive diseases

    Energy Technology Data Exchange (ETDEWEB)

    Aoki, S.; Yoshikawa, T.; Hori, M.; Ishigame, K.; Nambu, A.; Kumagai, H.; Araki, T. [Dept. of Radiology, Yamanashi Medical Univ. (Japan)

    2000-12-01

    Although spatial resolution of current MR angiography is excellent, temporal resolution has remained unsatisfactory. We evaluated clinical applicability of 2D thick-slice, contrast-enhanced subtraction MR angiography (2D-MR digital subtraction angiography) with sub-second temporal resolution in cerebrovascular occlusive diseases. Twenty-five patients with cerebrovascular occlusive diseases (8 moyamoya diseases, 10 proximal internal carotid occlusions, and 2 sinus thromboses) were studied with a 1.5-T MR unit. The MR digital subtraction angiography (MRDSA) was performed per 0.97 s continuously just after a bolus injection of 15 ml of gadolinium chelates up to 40 s in sagittal (covering hemisphere) or coronal planes. Subtraction images were generated at a workstation. We evaluated imaging quality and hemodynamic information of MRDSA in comparison with those of routine MR imaging, non-contrast MR angiography, and X-ray intra-arterial DSA. Major cerebral arteries, all of the venous sinuses, and most tributaries were clearly visualized with 2D MRDSA. Also, pure arterial phases were obtained in all cases. The MRDSA technique demonstrated prolonged circulation in sinus thromboses, distal patent lumen of proximal occlusion, and some collateral circulation. Such hemodynamic information was comparable to that of intra-arterial DSA. Two-dimensional thick-slice MRDSA with high temporal resolution has a unique ability to demonstrate cerebral hemodynamics equivalent to that of intra-arterial DSA and may play an important role for evaluation of cerebrovascular occlusive diseases. (orig.)

  17. Tomography of photon-added and photon-subtracted states

    NARCIS (Netherlands)

    Bazrafkan, MR; Man'ko, [No Value

    2003-01-01

    The purpose of this paper is to introduce symplectic and optical tomograms of photon-added and photon-subtracted quantum states. Explicit relations for the tomograms of photon-added and photon-subtracted squeezed coherent states and squeezed number states are obtained. Generating functions for the m

  18. Developing a Model to Support Students in Solving Subtraction

    NARCIS (Netherlands)

    Murdiyani, N.M.; Zulkardi, Z.; Putri, R.I.; van Eerde, H.A.A.; van Galen, F.H.J.

    2013-01-01

    Subtraction has two meanings and each meaning leads to the different strategies. The meaning of “taking away something” suggests a direct subtraction, while the meaning of “determining the difference between two numbers” is more likely to be modeled as indirect addition. Many prior researches found

  19. Developing a Model to Support Students in Solving Subtraction

    NARCIS (Netherlands)

    Murdiyani, N.M.; Zulkardi, Z.; Putri, R.I.; van Eerde, H.A.A.|info:eu-repo/dai/nl/071855343; van Galen, F.H.J.|info:eu-repo/dai/nl/069437025

    2013-01-01

    Subtraction has two meanings and each meaning leads to the different strategies. The meaning of “taking away something” suggests a direct subtraction, while the meaning of “determining the difference between two numbers” is more likely to be modeled as indirect addition. Many prior researches found

  20. Developing a Model to Support Students in Solving Subtraction

    Science.gov (United States)

    Murdiyani, Nila Mareta; Zulkardi; Putri, Ratu Ilma Indra; van Eerde, Dolly; van Galen, Frans

    2013-01-01

    Subtraction has two meanings and each meaning leads to the different strategies. The meaning of "taking away something" suggests a direct subtraction, while the meaning of "determining the difference between two numbers" is more likely to be modeled as indirect addition. Many prior researches found that the second meaning and…

  1. Tomography of photon-added and photon-subtracted states

    NARCIS (Netherlands)

    Bazrafkan, MR; Man'ko, [No Value

    The purpose of this paper is to introduce symplectic and optical tomograms of photon-added and photon-subtracted quantum states. Explicit relations for the tomograms of photon-added and photon-subtracted squeezed coherent states and squeezed number states are obtained. Generating functions for the

  2. [The three-dimension spectral subtraction fluorescence to check adulteration of diesel oil by 120# solvent naphtha].

    Science.gov (United States)

    Yang, Ren-jie; Xu, Xiao-xuan; Shang, Li-ping; Xu, Jia-lin; Zhang, Cun-zhou

    2006-01-01

    The characteristics of a adulterated sample of diesel oil by 120# solvent naphtha were studied with three-dimension spectral subtraction fluorescence technique, and it is shown that the technique could determine quickly whether there is a adulterated sample of 120# solvent naphtha in diesel. At the same time, by measuring the volume of three-dimension spectral subtraction fluorescence graph, the authors found that this total volume is directly related to the concentration of the adulterant present in the sample. The study is important for us to analyse whether there is a adulterated sample of 120# solvent naphtha in diesel, and is of significance for us to maintain the stability of market.

  3. Ectopic parathyroid gland. Localization with thallium-201 SPECT

    Energy Technology Data Exchange (ETDEWEB)

    Ziffer, J.A.; Fajman, W.A.

    1987-08-01

    Dual isotope Tl-201/Tc-99m subtraction is a useful technique for localization of abnormal parathyroid glands. A case of tomographic localization of nonsubtracted Tl-201 to a mediastinal parathyroid is reported and the possible benefit of this method discussed.

  4. A phase retrieval method of interferograms add-subtracting based on two-step phase shifting.

    Science.gov (United States)

    Xu, Yuanyuan; Wang, Yawei; Ji, Ying; Jin, Weifeng; Bu, Min; Shang, Xuefu

    2014-01-01

    A phase retrieval method is introduced in quantitative phase imaging (QPI) based on two-step phase-shifting technique. By acquiring two measured interferograms and calculating the addition and subtraction between them, the quantitative phase information can be directly retrieved. This method is illustrated by both theory and simulation experiments of a ball. The results of the simulation and the experiment of the red blood cell show a good agreement, demonstrating its application for studying cells.

  5. Removal of power-line interference from the ECG: a review of the subtraction procedure

    Directory of Open Access Journals (Sweden)

    Christov Ivaylo

    2005-08-01

    Full Text Available Abstract Background Modern biomedical amplifiers have a very high common mode rejection ratio. Nevertheless, recordings are often contaminated by residual power-line interference. Traditional analogue and digital filters are known to suppress ECG components near to the power-line frequency. Different types of digital notch filters are widely used despite their inherent contradiction: tolerable signal distortion needs a narrow frequency band, which leads to ineffective filtering in cases of larger frequency deviation of the interference. Adaptive filtering introduces unacceptable transient response time, especially after steep and large QRS complexes. Other available techniques such as Fourier transform do not work in real time. The subtraction procedure is found to cope better with this problem. Method The subtraction procedure was developed some two decades ago, and almost totally eliminates power-line interference from the ECG signal. This procedure does not affect the signal frequency components around the interfering frequency. Digital filtering is applied on linear segments of the signal to remove the interference components. These interference components are stored and further subtracted from the signal wherever non-linear segments are encountered. Results Modifications of the subtraction procedure have been used in thousands of ECG instruments and computer-aided systems. Other work has extended this procedure to almost all possible cases of sampling rate and interference frequency variation. Improved structure of the on-line procedure has worked successfully regardless of the multiplicity between the sampling rate and the interference frequency. Such flexibility is due to the use of specific filter modules. Conclusion The subtraction procedure has largely proved advantageous over other methods for power-line interference cancellation in ECG signals.

  6. Accessing the diffracted wavefield by coherent subtraction

    Science.gov (United States)

    Schwarz, Benjamin; Gajewski, Dirk

    2017-10-01

    Diffractions have unique properties which are still rarely exploited in common practice. Aside from containing subwavelength information on the scattering geometry or indicating small-scale structural complexity, they provide superior illumination compared to reflections. While diffraction occurs arguably on all scales and in most realistic media, the respective signatures typically have low amplitudes and are likely to be masked by more prominent wavefield components. It has been widely observed that automated stacking acts as a directional filter favouring the most coherent arrivals. In contrast to other works, which commonly aim at steering the summation operator towards fainter contributions, we utilize this directional selection to coherently approximate the most dominant arrivals and subtract them from the data. Supported by additional filter functions which can be derived from wave front attributes gained during the stacking procedure, this strategy allows for a fully data-driven recovery of faint diffractions and makes them accessible for further processing. A complex single-channel field data example recorded in the Aegean sea near Santorini illustrates that the diffracted background wavefield is surprisingly rich and despite the absence of a high channel count can still be detected and characterized, suggesting a variety of applications in industry and academia.

  7. Gd-enhanced subtraction MR venography

    Energy Technology Data Exchange (ETDEWEB)

    Hoshi, Toshiko; Hachiya, Takashi; Kanauchi, Tetsu; Hando, Yumiko; Homma, Tsuguo [Saitama Cardiovascular and Respiratory Center, Konan (Japan)

    1999-10-01

    We succeeded in distinctly imaging the calf veins using Gd-enhanced subtraction MR venography (Gd SMRV). Gd SMRV was performed in 15 normal legs, 33 varicose legs and 22 legs with suspected deep venous thrombosis. Conventional venography was performed in 46 legs in all. The deep veins of the calf, greater saphenous vein, and intramuscular veins had high rates of demonstration in normal legs and varicose legs (84, 100%, 87, 97%, 67, 73%). The varices were also well demonstrated (100%). When Gd SMRV was compared with conventional venography in terms of diagnosis of calf venous thrombosis, the sensitivity of this method was 100%, specificity was 92% and accuracy was 93%. We found high intensity thrombi on precontrast images in most cases, a finding that was important for the diagnosis of local thrombi. This method was non-invasive and was able to clearly visualize veins in the calf. We concluded that Gd SMRV was useful for calf venous disease, especially calf venous thrombosis. (author)

  8. Digital contrast subtraction radiography for proximal caries diagnosis

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Byung Cheol; Yoon, Suk Ja [Department of Dental Radiology, Chonnam National University Hospital, Gwangju (Korea, Republic of)

    2002-06-15

    To determine whether subtraction images utilizing contrast media can improve the diagnostic performance of proximal caries diagnosis compared to conventional periapical radiographic images. Thirty-six teeth with 57 proximal surfaces were radiographied using a size no.2 RVG-ui sensor (Trophy Radiology, Marne-la-Vallee, France). The teeth immersed in water-soluble contrast media and subtraction images were taken. Each tooth was then sectioned for histologic examination. The digital radiographic images and subtraction images were examined and interpreted by three dentists for proximal caries. The results of the proximal caries diagnosis were then verified with the results of the histologic examination. The proximal caries sensitivity using digital subtraction radiography was significantly higher than simply examining a single digital radiograph. The sensitivity of the proximal dentinal carious lesion when analyzed with the subtraction radiograph and the radiograph together was higher than with the subtraction radiograph or the radiograph alone. The use of subtraction radiography with contrast media may be useful for detecting proximal dentinal carious lesions.

  9. Temporal subtraction system on torso FDG-PET scans based on statistical image analysis

    Science.gov (United States)

    Shimizu, Yusuke; Hara, Takeshi; Fukuoka, Daisuke; Zhou, Xiangrong; Muramatsu, Chisako; Ito, Satoshi; Hakozaki, Kenta; Kumita, Shin-ichiro; Ishihara, Kei-ichi; Katafuchi, Tetsuro; Fujita, Hiroshi

    2013-02-01

    Diagnostic imaging on FDG-PET scans was often used to evaluate chemotherapy results of cancer patients. Radiologists compare the changes of lesions' activities between previous and current examinations for the evaluation. The purpose of this study was to develop a new computer-aided detection (CAD) system with temporal subtraction technique for FDGPET scans and to show the fundamental usefulness based on an observer performance study. Z-score mapping based on statistical image analysis was newly applied to the temporal subtraction technique. The subtraction images can be obtained based on the anatomical standardization results because all of the patients' scans were deformed into standard body shape. An observer study was performed without and with computer outputs to evaluate the usefulness of the scheme by ROC (receiver operating characteristics) analysis. Readers responded as confidence levels on a continuous scale from absolutely no change to definitely change between two examinations. The recognition performance of the computer outputs for the 43 pairs was 96% sensitivity with 31.1 false-positive marks per scan. The average of area-under-the-ROC-curve (AUC) from 4 readers in the observer performance study was increased from 0.85 without computer outputs to 0.90 with computer outputs (p=0.0389, DBM-MRMC). The average of interpretation time was slightly decreased from 42.11 to 40.04 seconds per case (p=0.625, Wilcoxon test). We concluded that the CAD system for torso FDG-PET scans with temporal subtraction technique might improve the diagnostic accuracy of radiologist in cancer therapy evaluation.

  10. Technical innovation: Multidimensional computerized software enabled subtraction computed tomographic angiography.

    Science.gov (United States)

    Bhatia, Mona; Rosset, Antoine; Platon, Alexandra; Didier, Dominique; Becker, Christoph D; Poletti, Pierre-Alexandre

    2010-01-01

    Computed tomographic angiography (CTA) is a frequent noninvasive alternative to digital subtraction angiography. We previously reported the development of a new subtraction software to overcome limitations of adjacent bone and calcification in CT angiographic subtraction. Our aim was to further develop and improve this fast and automated computerized software, universally available for free use and compatible with most CT scanners, thus enabling better delineation of vascular structures, artifact reduction, and shorter reading times with potential clinical benefits. This computer-based free software will be available as an open source in the next release of OsiriX at the Web site http://www.osirix-viewer.com.

  11. Sensory subtraction in robot-assisted surgery: fingertip skin deformation feedback to ensure safety and improve transparency in bimanual haptic interaction.

    Science.gov (United States)

    Meli, Leonardo; Pacchierotti, Claudio; Prattichizzo, Domenico

    2014-04-01

    This study presents a novel approach to force feedback in robot-assisted surgery. It consists of substituting haptic stimuli, composed of a kinesthetic component and a skin deformation, with cutaneous stimuli only. The force generated can then be thought as a subtraction between the complete haptic interaction, cutaneous, and kinesthetic, and the kinesthetic part of it. For this reason, we refer to this approach as sensory subtraction. Sensory subtraction aims at outperforming other nonkinesthetic feedback techniques in teleoperation (e.g., sensory substitution) while guaranteeing the stability and safety of the system. We tested the proposed approach in a challenging 7-DoF bimanual teleoperation task, similar to the Pegboard experiment of the da Vinci Skills Simulator. Sensory subtraction showed improved performance in terms of completion time, force exerted, and total displacement of the rings with respect to two popular sensory substitution techniques. Moreover, it guaranteed a stable interaction in the presence of a communication delay in the haptic loop.

  12. Estimating background-subtracted fluorescence transients in calcium imaging experiments: a quantitative approach.

    Science.gov (United States)

    Joucla, Sébastien; Franconville, Romain; Pippow, Andreas; Kloppenburg, Peter; Pouzat, Christophe

    2013-08-01

    Calcium imaging has become a routine technique in neuroscience for subcellular to network level investigations. The fast progresses in the development of new indicators and imaging techniques call for dedicated reliable analysis methods. In particular, efficient and quantitative background fluorescence subtraction routines would be beneficial to most of the calcium imaging research field. A background-subtracted fluorescence transients estimation method that does not require any independent background measurement is therefore developed. This method is based on a fluorescence model fitted to single-trial data using a classical nonlinear regression approach. The model includes an appropriate probabilistic description of the acquisition system's noise leading to accurate confidence intervals on all quantities of interest (background fluorescence, normalized background-subtracted fluorescence time course) when background fluorescence is homogeneous. An automatic procedure detecting background inhomogeneities inside the region of interest is also developed and is shown to be efficient on simulated data. The implementation and performances of the proposed method on experimental recordings from the mouse hypothalamus are presented in details. This method, which applies to both single-cell and bulk-stained tissues recordings, should help improving the statistical comparison of fluorescence calcium signals between experiments and studies.

  13. Improvements in floating point addition/subtraction operations

    Energy Technology Data Exchange (ETDEWEB)

    Farmwald, P.M.

    1984-02-24

    Apparatus is described for decreasing the latency time associated with floating point addition and subtraction in a computer, using a novel bifurcated, pre-normalization/post-normalization approach that distinguishes between differences of floating point exponents.

  14. An auto-adaptive background subtraction method for Raman spectra

    Science.gov (United States)

    Xie, Yi; Yang, Lidong; Sun, Xilong; Wu, Dewen; Chen, Qizhen; Zeng, Yongming; Liu, Guokun

    2016-05-01

    Background subtraction is a crucial step in the preprocessing of Raman spectrum. Usually, parameter manipulating of the background subtraction method is necessary for the efficient removal of the background, which makes the quality of the spectrum empirically dependent. In order to avoid artificial bias, we proposed an auto-adaptive background subtraction method without parameter adjustment. The main procedure is: (1) select the local minima of spectrum while preserving major peaks, (2) apply an interpolation scheme to estimate background, (3) and design an iteration scheme to improve the adaptability of background subtraction. Both simulated data and Raman spectra have been used to evaluate the proposed method. By comparing the backgrounds obtained from three widely applied methods: the polynomial, the Baek's and the airPLS, the auto-adaptive method meets the demand of practical applications in terms of efficiency and accuracy.

  15. Increasing Entanglement between Gaussian States by Coherent Photon Subtraction

    DEFF Research Database (Denmark)

    Ourjoumtsev, Alexei; Dantan, Aurelien Romain; Tualle Brouri, Rosa

    2007-01-01

    We experimentally demonstrate that the entanglement between Gaussian entangled states can be increased by non-Gaussian operations. Coherent subtraction of single photons from Gaussian quadrature-entangled light pulses, created by a nondegenerate parametric amplifier, produces delocalized states w...

  16. Background Subtraction for Automated Multisensor Surveillance: A Comprehensive Review

    Directory of Open Access Journals (Sweden)

    Cristani Marco

    2010-01-01

    Full Text Available Background subtraction is a widely used operation in the video surveillance, aimed at separating the expected scene (the background from the unexpected entities (the foreground. There are several problems related to this task, mainly due to the blurred boundaries between background and foreground definitions. Therefore, background subtraction is an open issue worth to be addressed under different points of view. In this paper, we propose a comprehensive review of the background subtraction methods, that considers also channels other than the sole visible optical one (such as the audio and the infrared channels. In addition to the definition of novel kinds of background, the perspectives that these approaches open up are very appealing: in particular, the multisensor direction seems to be well-suited to solve or simplify several hoary background subtraction problems. All the reviewed methods are organized in a novel taxonomy that encapsulates all the brand-new approaches in a seamless way.

  17. Background Subtraction for Automated Multisensor Surveillance: A Comprehensive Review

    Science.gov (United States)

    Cristani, Marco; Farenzena, Michela; Bloisi, Domenico; Murino, Vittorio

    2010-12-01

    Background subtraction is a widely used operation in the video surveillance, aimed at separating the expected scene (the background) from the unexpected entities (the foreground). There are several problems related to this task, mainly due to the blurred boundaries between background and foreground definitions. Therefore, background subtraction is an open issue worth to be addressed under different points of view. In this paper, we propose a comprehensive review of the background subtraction methods, that considers also channels other than the sole visible optical one (such as the audio and the infrared channels). In addition to the definition of novel kinds of background, the perspectives that these approaches open up are very appealing: in particular, the multisensor direction seems to be well-suited to solve or simplify several hoary background subtraction problems. All the reviewed methods are organized in a novel taxonomy that encapsulates all the brand-new approaches in a seamless way.

  18. Developing a Model to Support Students in Solving Subtraction

    Directory of Open Access Journals (Sweden)

    Nila Mareta Murdiyani

    2013-01-01

    Full Text Available Subtraction has two meanings and each meaning leads to the different strategies. The meaning of “taking away something” suggests a direct subtraction, while the meaning of “determining the difference between two numbers” is more likely to be modeled as indirect addition. Many prior researches found that the second meaning and second strategy rarely appeared in the mathematical textbooks and teacher explanations, including in Indonesia. Therefore, this study was conducted to contribute to the development of a local instruction theory for subtraction by designing instructional activities that can facilitate first grade of primary school students to develop a model in solving two digit numbers subtraction. Consequently, design research was chosen as an appropriate approach for achieving the research aim and Realistic Mathematics Education (RME was used as a guide to design the lesson. This study involved 6 students in the pilot experiment, 31 students in the teaching experiment, and a first grade teacher of SDN 179 Palembang. The  result of this study shows that the beads string could bridge students from the contextual problems (taking ginger candies and making grains bracelets to the use of the empty number line. It also shows that the empty number line could promote students to  use different strategies (direct subtraction, indirect addition, and indirect subtraction in solving subtraction problems. Based on these findings, it is recommended to apply RME in the teaching learning process to make it more meaningful for students. Keywords: Subtraction, Design Research, Realistic Mathematics Education, The Beads String, The Empty Number Line DOI: http://dx.doi.org/10.22342/jme.4.1.567.95-112

  19. Differential cDNA cloning by enzymatic degrading subtraction (EDS).

    OpenAIRE

    1994-01-01

    We describe a new method, called enzymatic degrading subtraction (EDS), for the construction of subtractive libraries from PCR amplified cDNA. The novel features of this method are that i) the tester DNA is blocked by thionucleotide incorporation; ii) the rate of hybridization is accelerated by phenol-emulsion reassociation; and iii) the driver cDNA and hybrid molecules are enzymatically removed by digestion with exonucleases III and VII rather than by physical partitioning. We demonstrate th...

  20. Voxel significance mapping in epilepsy studies using subtraction ictal SPECT

    Science.gov (United States)

    Brinkmann, Benjamin H.; O'Brien, Terence J.; Webster, Desmond B.; Robins, Peter D.; Mullan, Brian P.; Robb, Richard A.

    1999-05-01

    Subtraction ictal SPECT coregistered to MRI (SISCOM) has been shown to aid epileptogenic localization and improve surgical outcomes in partial epilepsy patients. This paper reports a new method of identifying significant areas of epileptogenic activation in the SISCOM subtraction image taking into account normal variation between sequential Tc-99m Ethyl Cysteinate Diethylester SPECT scans of single individuals. The method uses the AIR 3.0 nonlinear registration software to combine a group of subtraction images into a common anatomical framework. A map of the pixel intensity standard deviation values in the subtraction images is created, and this map is nonlinearly registered to a patient's SISCOM subtraction image. Pixels in the patient subtraction image may then be evaluated based upon the statistical characteristics of corresponding pixels in the atlas. Validation experiments were performed to verify that local image variances are not constant across the image and that nonlinear registration preserves local image variances. SISCOM images created with the voxel variance method were rated higher in quality than the conventional image variance method in images from fifteen patients. No difference in localization rate was observed between the voxel variance mapping and image variance methods. The voxel significance mapping method was shown to improve the quality of clinical SISCOM images without removing localizing information.

  1. Developing a Model to Support Students in Solving Subtraction

    Directory of Open Access Journals (Sweden)

    Nila Mareta Murdiyani

    2013-01-01

    Full Text Available Subtraction has two meanings and each meaning leads to the differentstrategies. The meaning of “taking away something” suggests a directsubtraction, while the meaning of “determining the difference betweentwo numbers” is more likely to be modeled as indirect addition. Manyprior researches found that the second meaning and second strategy rarely appeared in the mathematical textbooks and teacher explanations, including in Indonesia. Therefore, this study was conducted to contribute to the development of a local instruction theory for subtraction by designing instructional activities that can facilitate first grade of primary school students to develop a model in solving two digit numbers subtraction. Consequently, design research was chosen as an appropriate approach for achieving the research aim and Realistic Mathematics Education (RME was used as a guide to design the lesson. This study involved 6 students in the pilot experiment, 31 students in the teaching experiment, and a first grade teacher of SDN 179 Palembang. The result of this study shows that the beads string could bridge students from the contextual problems (taking ginger candies and making grains bracelets to the use of the empty number line. It also shows that the empty number line could promote students to use different strategies (direct subtraction, indirect addition, and indirect subtraction in solving subtraction problems. Based on these findings, it is recommended to apply RME in the teaching learning process to make it more meaningful for students.

  2. Subtraction MRI versus diffusion weighted imaging: Which is more accurate in assessment of hepatocellular carcinoma after Trans Arterial Chemoembolization (TACE?

    Directory of Open Access Journals (Sweden)

    Noha Abd ElShafy ElSaid

    2016-12-01

    Full Text Available This study aims to compare the role of both subtraction MRI and Diffusion weighted images in assessment of HCC after trans-arterial chemo embolization (TACE. Patients and methods: 32 patients having 54 HCC lesions underwent TACE. Ages ranged between 59 and 73 years (mean age 59.6; there were 26 males and 6 females. All examinations were performed using Philips 1.5 T MRI (Achieva. Pre contrast: T1, T2W and In phase and out phase gradient echo sequence, dynamic: eTHRIVE technique performed. Subtraction of an unenhanced T1-weighted was from the identical post enhancement sequences in early angiographic and late arterial phases. Diffusion imaging: it was performed using single-shot spin-echo echo-planar imaging with b = 0, 300, 600 mm/s2. DWI was used to create ADC maps. Two readers blinded to each other assessed subtraction of dynamic study and DWI technique to evaluate post treatment response. Results: Reader 1 subtraction dynamic MRI sensitivity = 97%, specificity = 100% PPV = 100% and NPV = 95% compared to 70.59%, 75%, 82.76% and 60% respectively in DWI. Reader 2 subtraction dynamic MRI sensitivity = 97%, specificity = 100% PPV = 100% and NPV = 95% compared to 76.5%, 90%, 92.8% and 69% respectively in DWI. Conclusion: DW-MRI had lower accuracy measures compared to subtraction MRI with increased false negative. DWI may act as a supplementary sequence to compensate for the dynamic MRI in patients who couldn't hold their breath adequately.

  3. The Reduction Of Motion Artifacts In Digital Subtraction Angiography By Geometrical Image Transformation

    Science.gov (United States)

    Fitzpatrick, J. Michael; Pickens, David R.; Mandava, Venkateswara R.; Grefenstette, John J.

    1988-06-01

    In the diagnosis of arteriosclerosis, radio-opaque dye is injected into the interior of the arteries to make them visible. Because of its increased contrast sensitivity, digital subtraction angiography has the potential for providing diagnostic images of arteries with reduced dye volumes. In the conventional technique, a mask image, acquired before the introduction of the dye, is subtracted from the contrast image, acquired after the dye is introduced, to produce a difference image in which only the dye in the arteries is visible. The usefulness of this technique has been severely limited by the image degradation caused by patient motion during image acquisition. This motion produces artifacts in the difference image that obscure the arteries. One technique for dealing with this problem is to reduce the degradation by means of image registration. The registration is carried out by means of a geometrical transformation of the mask image before subtraction so that it is in registration with the contrast image. This paper describes our technique for determining an optimal transformation. We employ a one-to-one elastic mapping and the Jacobian of that mapping to produce a geometrical image transformation. We choose a parameterized class of such mappings and use a heuristic search algorithm to optimize the parameters to minimize the severity of the motion artifacts. To increase the speed of the optimization process we use a statistical image comparison technique that provides a quick approximate evaluation of each image transformation. We present the experimental results of the application of our registration system to mask-contrast pairs, for images acquired from a specially designed phantom (described in a companion paper), and for clinical images.

  4. Nonenhanced magnetic resonance angiography (MRA) of the calf arteries at 3 Tesla: intraindividual comparison of 3D flow-dependent subtractive MRA and 2D flow-independent non-subtractive MRA

    Energy Technology Data Exchange (ETDEWEB)

    Knobloch, Gesine; Lauff, Marie-Teres; Hirsch, Sebastian; Hamm, Bernd; Wagner, Moritz [Charite - Universitaetsmedizin Berlin, Department of Radiology, Berlin (Germany); Schwenke, Carsten [SCO:SSiS Statistical Consulting, Berlin (Germany)

    2016-12-15

    To prospectively compare 3D flow-dependent subtractive MRA vs. 2D flow-independent non-subtractive MRA for assessment of the calf arteries at 3 Tesla. Forty-two patients with peripheral arterial occlusive disease underwent nonenhanced MRA of calf arteries at 3 Tesla with 3D flow-dependent subtractive MRA (fast spin echo sequence; 3D-FSE-MRA) and 2D flow-independent non-subtractive MRA (balanced steady-state-free-precession sequence; 2D-bSSFP-MRA). Moreover, all patients underwent contrast-enhanced MRA (CE-MRA) as standard-of-reference. Two readers performed a per-segment evaluation for image quality (4 = excellent to 0 = non-diagnostic) and severity of stenosis. Image quality scores of 2D-bSSFP-MRA were significantly higher compared to 3D-FSE-MRA (medians across readers: 4 vs. 3; p < 0.0001) with lower rates of non-diagnostic vessel segments on 2D-bSSFP-MRA (reader 1: <1 % vs. 15 %; reader 2: 1 % vs. 29 %; p < 0.05). Diagnostic performance of 2D-bSSFP-MRA and 3D-FSE-MRA across readers showed sensitivities of 89 % (214/240) vs. 70 % (168/240), p = 0.0153; specificities: 91 % (840/926) vs. 63 % (585/926), p < 0.0001; and diagnostic accuracies of 90 % (1054/1166) vs. 65 % (753/1166), p < 0.0001. 2D flow-independent non-subtractive MRA (2D-bSSFP-MRA) is a robust nonenhanced MRA technique for assessment of the calf arteries at 3 Tesla with significantly higher image quality and diagnostic accuracy compared to 3D flow-dependent subtractive MRA (3D-FSE-MRA). (orig.)

  5. Fingerprinting the Asterid species using subtracted diversity array reveals novel species-specific sequences.

    Directory of Open Access Journals (Sweden)

    Nitin Mantri

    Full Text Available BACKGROUND: Asterids is one of the major plant clades comprising of many commercially important medicinal species. One of the major concerns in medicinal plant industry is adulteration/contamination resulting from misidentification of herbal plants. This study reports the construction and validation of a microarray capable of fingerprinting medicinally important species from the Asterids clade. METHODOLOGY/PRINCIPAL FINDINGS: Pooled genomic DNA of 104 non-asterid angiosperm and non-angiosperm species was subtracted from pooled genomic DNA of 67 asterid species. Subsequently, 283 subtracted DNA fragments were used to construct an Asterid-specific array. The validation of Asterid-specific array revealed a high (99.5% subtraction efficiency. Twenty-five Asterid species (mostly medicinal representing 20 families and 9 orders within the clade were hybridized onto the array to reveal its level of species discrimination. All these species could be successfully differentiated using their hybridization patterns. A number of species-specific probes were identified for commercially important species like tea, coffee, dandelion, yarrow, motherwort, Japanese honeysuckle, valerian, wild celery, and yerba mate. Thirty-seven polymorphic probes were characterized by sequencing. A large number of probes were novel species-specific probes whilst some of them were from chloroplast region including genes like atpB, rpoB, and ndh that have extensively been used for fingerprinting and phylogenetic analysis of plants. CONCLUSIONS/SIGNIFICANCE: Subtracted Diversity Array technique is highly efficient in fingerprinting species with little or no genomic information. The Asterid-specific array could fingerprint all 25 species assessed including three species that were not used in constructing the array. This study validates the use of chloroplast genes for bar-coding (fingerprinting plant species. In addition, this method allowed detection of several new loci that can be

  6. Subtraction and dynamic MR images of breast cancer

    Energy Technology Data Exchange (ETDEWEB)

    Murakami, Yoshitaka; Aoki, Manabu; Harada, Junta (Jikei Univ., Tokyo (Japan). School of Medicine)

    1993-04-01

    The purpose of this study was to evaluate the diagnostic effectiveness of subtraction and dynamic MR imaging in patients with breast masses. In 23 breast cancers and six fibroadenomas, spin echo T1 images were obtained at 0.2 Tesla before and every minute after intravenous injection of Gd-DTPA (0.1 or 0.2 mmol/kg). Subtraction images were obtained sequentially on the CRT monitor. All breast masses were enhanced after gadolinium and stood out as bright lesions on subtraction images. The tumor margin and its extension were more precisely evaluated on subtraction MR images than on conventional postcontrast MR images. Breast cancer showed a characteristic time-intensity curve with an early peak, in contrast to fibroadenoma, which showed a gradual increase in signal intensity. Subtraction MR imaging is a simple method for the evaluation of breast masses, and further, the time-intensity curve obtained by dynamic study is helpful in the differential diagnosis of lesions. (author).

  7. Digital subtraction peripheral angiography using image stacking: initial clinical results.

    Science.gov (United States)

    Kump, K S; Sachs, P B; Wilson, D L

    2001-07-01

    Using clinically acquired x-ray angiography image sequences, we compared three algorithms for creating a single diagnostic quality image that combined input images containing flowing contrast agent. These image-stacking algorithms were: maximum opacity with the minimum gray-scale value across time recorded at each spatial location, (REC) recursive temporal filtering followed by a maximum opacity operation, and (AMF) an approximate matched filter consisting of a convolution with a kernel approximating the matched filter followed by a maximum opacity operation. Eighteen clinical exams of the peripheral arteries of the legs were evaluated. AMF gave 2.7 times greater contrast to noise ratio than the single best subtraction image and 1.3 times improvement over REC, the second best stacking algorithm. This is consistent with previous simulations showing that AMF performs nearly equal to the optimal result from matched filtering without the well-known limitations. For example, unlike matched filtering, AMF filter coefficients were obtained automatically using an image-processing algorithm. AMF effectively brought out small collateral arteries, otherwise difficult to see, without degrading artery sharpness or stenosis grading. Comparing results using reduced and full contrast agent volumes demonstrated that contrast agent load could be reduced to one-third of the conventional amount with AMF processing. By simulating reduced x-ray exposures on clinical exams, we determined that x-ray exposure could be reduced by 80% with AMF processing. We conclude that AMF is a promising, potential technique for reducing contrast agent load and for improving vessel visibility, both very important characteristics for vascular imaging.

  8. 前柱张开与闭合对经椎弓根椎体截骨治疗强直性脊柱炎胸腰椎后凸畸形疗效的影响%The effect of anterior column open or close technique in pedicle subtraction osteotomy for the treatment of thoracic/lumbar kyphosis deformity in ankylosing spondylitis patients

    Institute of Scientific and Technical Information of China (English)

    邱勇

    2010-01-01

    @@ 目前治疗强直性脊柱炎(ankylosing spondylitis,AS)胸腰椎后凸畸形的后路截骨矫形术式主要有两种,即多节段经椎间关节截骨术(Smith-Petersen osteotomies,SPOs)和经椎弓根截骨术(pedicle subtraction osteotomy,PSO)[1-2].这两种截骨方法术后近期疗效相近,但SPOs术后后柱截骨面融合较慢,且前柱有所延长,支撑作用不完全,术后易发生矫正丢失.

  9. pyKLIP: PSF Subtraction for Exoplanets and Disks

    Science.gov (United States)

    Wang, Jason J.; Ruffio, Jean-Baptise; De Rosa, Robert J.; Aguilar, Jonathan; Wolff, Schuyler G.; Pueyo, Laurent

    2015-06-01

    pyKLIP subtracts out the stellar PSF to search for directly-imaged exoplanets and disks using a Python implementation of the Karhunen-Loève Image Projection (KLIP) algorithm. pyKLIP supports ADI, SDI, and ADI+SDI to model the stellar PSF and offers a large array of PSF subtraction parameters to optimize the reduction. pyKLIP relies on a minimal amount of dependencies (numpy, scipy, and astropy) and parallelizes the KLIP algorithm to speed up the reduction. pyKLIP supports GPI and P1640 data and can interface with other data sources with the addition of new modules. It also can inject simulated planets and disks as well as automatically search for point sources in PSF-subtracted data.

  10. Proper image subtraction - optimal transient detection, photometry and hypothesis testing

    CERN Document Server

    Zackay, Barak; Gal-Yam, Avishay

    2016-01-01

    Transient detection and flux measurement via image subtraction stand at the base of time domain astronomy. Due to the varying seeing conditions, the image subtraction process is non-trivial, and existing solutions suffer from a variety of problems. Starting from basic statistical principles, we develop the optimal statistic for transient detection, flux measurement and any image-difference hypothesis testing. We derive a closed-form statistic that: (i) Is mathematically proven to be the optimal transient detection statistic in the limit of background-dominated noise; (ii) Is numerically stable; (iii) For accurately registered, adequately sampled images, does not leave subtraction or deconvolution artifacts; (iv) Allows automatic transient detection to the theoretical sensitivity limit by providing credible detection significance; (v) Has uncorrelated white noise; (vi) Is a sufficient statistic for any further statistical test on the difference image, and in particular, allows to distinguish particle hits and ...

  11. Proposed smart integrated-optical preprocessor using holographic subtraction

    Science.gov (United States)

    Verber, C. M.; Vahey, D. W.

    1979-01-01

    The paper presents a proposed integrated-optical preprocessor with a holographic subtraction. It is based on an optical analog of a set of N analog voltages formed by passing an optical plane wave, confined in an electrooptic waveguide, under a set of N electrodes to which the voltages are applied; in the limit in which diffraction is ignored, the wavefront of the emerging guided wave will have superimposed upon it N discrete phase shifts. Processors which operate upon voltages encoded in this manner are being fabricated; they include a comparator in which incoming data are compared to a holographic record of the optical analog of a reference set, and a 'smart' system based upon holographic self-subtraction, in which the processor can independently adapt to changes in background information. The preprocessor operation is described in the screening, identification, and the self-subtraction modes, and implementation of devices in an integrated optical configuration is discussed.

  12. Feasibility investigation of integrated optics Fourier transform devices. [holographic subtraction for multichannel data preprocessing

    Science.gov (United States)

    Verber, C. M.; Vahey, D. W.; Wood, V. E.; Kenan, R. P.; Hartman, N. F.

    1977-01-01

    The possibility of producing an integrated optics data processing device based upon Fourier transformations or other parallel processing techniques, and the ways in which such techniques may be used to upgrade the performance of present and projected NASA systems were investigated. Activities toward this goal include; (1) production of near-diffraction-limited geodesic lenses in glass waveguides; (2) development of grinding and polishing techniques for the production of geodesic lenses in LiNbO3 waveguides; (3) development of a characterization technique for waveguide lenses; and (4) development of a theory for corrected aspheric geodesic lenses. A holographic subtraction system was devised which should be capable of rapid on-board preprocessing of a large number of parallel data channels. The principle involved is validated in three demonstrations.

  13. Construction and partial sequencing of a subtractive library in Calcutta 4 (Musa AA in early stage of infection with Mycosphaerella fijiensis Morelet

    Directory of Open Access Journals (Sweden)

    Milady Mendoza-Rodríguez

    2006-10-01

    Full Text Available The study of genes involved in plant defense response against pathogen attack, is one of most important steps leading to the elucidation of disease resistance molecular mechanisms. The generation of subtracted deoxyribonucleic acid libraries (cDNA, by means of suppression subtractive hybridization technique (SSH, has been used for this purpose. A subtractive hybridization was made between a cDNA population obtained from ‘Calcutta 4’ inoculated leaves with M. fijiensis (CCIBP-Pf83 and a mixture of cDNA from ‘Calcutta 4’ non inoculated leaves and mycelium. Leaves samples were taken at 6, 10 and 12 days after inoculation. The subtracted library was obtained by cloning and transformation of subtracted products and as a result, 600 recombinants clones were obtained. Sequence analysis of sixty nine clones, revealed redundancy of the expressed sequence tags and most of them showed no homology with reported sequences at databases and only 13 % had a high homology with metalothioneins. The results constitute a step in advance in the molecular study of Musa-Mycosphaerella fijiensis interaction. Key words: Banana-Mycosphaerella fijiensis interaction, BlackSigatoka, Musa spp., suppression subtractive hybridization

  14. Genetic differences between two Leishmania major-like strains revealed by suppression subtractive hybridization.

    Science.gov (United States)

    Wu, Ângela C A; Freitas, Michelle A R; Silva, Soraia de O; Nogueira, Paula M; Soares, Rodrigo P; Pesquero, João Bosco; Gomes, Maria A; Pesquero, Jorge L; Melo, Maria N

    2015-01-01

    Leishmania major, the causative agent of zoonotic leishmaniasis, is restricted to Old World countries. Molecular and biochemical techniques have been used to identify some L. major-like isolated in South America including Brazil. Here, two L. major-like strains, one virulent (BH49) and one non-virulent (BH121), were subjected to suppression subtractive hybridization (SSH) technique in order to identify differentially expressed genes. SSH technique identified nine cDNA fragments exhibiting high homology to previously sequenced L. major genes. Five cDNAs (four specific for BH49 and one for BH121) were confirmed by RT-PCR. Among those differentially expressed subtracted genes, some were involved in physiological processes including metabolism, translation and destination of proteins, production of energy, virulence factors and unknown functions. Western-blot analysis confirmed a higher expression level of β-1,3-galactosyl residues in L. major-like lipophosphoglycan (LPG). This molecular analysis opens the possibility for identification of potential virulence factors not only in different strains, but also in others species of Leishmania.

  15. Identification of differentially expressed genes in uveal melanoma using suppressive subtractive hybridization

    Science.gov (United States)

    Landreville, Solange; Lupien, Caroline B.; Vigneault, Francois; Gaudreault, Manon; Mathieu, Mélissa; Rousseau, Alain P.; Guérin, Sylvain L.

    2011-01-01

    Purpose Uveal melanoma (UM) is the most common primary cancer of the eye, resulting not only in vision loss, but also in metastatic death. This study attempts to identify changes in the patterns of gene expression that lead to malignant transformation and proliferation of normal uveal melanocytes (UVM) using the Suppressive Subtractive Hybridization (SSH) technique. Methods The SSH technique was used to isolate genes that are differentially expressed in the TP31 cell line derived from a primary UM compared to UVM. The expression level of selected genes was further validated by microarray, semi-quantitative RT–PCR and western blot analyses. Results Analysis of the subtracted libraries revealed that 37 and 36 genes were, respectively, up- and downregulated in TP31 cells compared to UVM. Differential expression of the majority of these genes was confirmed by comparing UM cells with UVM by microarray. The expression pattern of selected genes was analyzed by semi-quantitative RT–PCR and western blot, and was found to be consistent with the SSH findings. Conclusions We demonstrated that the SSH technique is efficient to detect differentially expressed genes in UM. The genes identified in this study represent valuable candidates for further functional analysis in UM and should be informative in studying the biology of this tumor. PMID:21647268

  16. Dual-Energy Subtraction Imaging for Diagnosing Vocal Cord Paralysis with Flat Panel Detector Radiography

    Energy Technology Data Exchange (ETDEWEB)

    Machida, Haruhiko; Yoda, Keiko; Arai, Yasuko [Tokyo Women' s Medical University Medical Center East, Tokyo (Japan)] (and others)

    2010-06-15

    To investigate the clinical feasibility of dual energy subtraction (DES) imaging to improve the delineation of the vocal cord and diagnostic accuracy of vocal cord paralysis as compared with the anterior-posterior view of flat panel detector (FPD) neck radiography. For 122 consecutive patients who underwent both a flexible laryngoscopy and conventional/DES FPD radiography, three blinded readers retrospectively graded the radiographs during phonation and inspiration on a scale of 1 (poor) to 5 (excellent) for the delineation of the vocal cord, and in consensus, reviewed the diagnostic accuracy of vocal cord paralysis employing the laryngoscopy as the reference. We compared vocal cord delineation scores and accuracy of vocal cord paralysis diagnosis by both conventional and DES techniques using ({kappa}statistics and assessing the area under the receiver operating characteristic curve (AUC). Vocal cord delineation scores by DES (mean, 4.2 {+-} 0.4) were significantly higher than those by conventional imaging (mean, 3.3 {+-} 0.5) (p < 0.0001). Sensitivity for diagnosing vocal cord paralysis by the conventional technique was 25%, whereas the specificity was 94%. Sensitivity by DES was 75%, whereas the specificity was 96%. The diagnostic accuracy by DES was significantly superior (({kappa}= 0.60, AUC = 0.909) to that by conventional technique ({kappa}= 0.18, AUC = 0.852) (p = 0.038). Dual energy subtraction is a superior method compared to the conventional FPD radiography for delineating the vocal cord and accurately diagnosing vocal cord paralysis.

  17. Evaluation of chronic periapical lesions by digital subtraction radiography by using Adobe Photoshop CS: a technical report.

    Science.gov (United States)

    Carvalho, Fabiola B; Gonçalves, Marcelo; Tanomaru-Filho, Mário

    2007-04-01

    The purpose of this study was to describe a new technique by using Adobe Photoshop CS (San Jose, CA) image-analysis software to evaluate the radiographic changes of chronic periapical lesions after root canal treatment by digital subtraction radiography. Thirteen upper anterior human teeth with pulp necrosis and radiographic image of chronic periapical lesion were endodontically treated and radiographed 0, 2, 4, and 6 months after root canal treatment by using a film holder. The radiographic films were automatically developed and digitized. The radiographic images taken 0, 2, 4, and 6 months after root canal therapy were submitted to digital subtraction in pairs (0 and 2 months, 2 and 4 months, and 4 and 6 months) choosing "image," "calculation," "subtract," and "new document" tools from Adobe Photoshop CS image-analysis software toolbar. The resulting images showed areas of periapical healing in all cases. According to this methodology, the healing or expansion of periapical lesions can be evaluated by means of digital subtraction radiography by using Adobe Photoshop CS software.

  18. Simplified expressions of the subtracted Kramers-Kronig relations using the expanded forms applied to ultrasonic power-law systems.

    Science.gov (United States)

    Mobley, Joel

    2010-01-01

    The Kramers-Kronig (KK) relations are a large class of integral transformations that exploit the broad principle of simple causality in order to link the physical properties of matter and materials. In applications to the complex-valued wavenumber for acoustic propagation, the method of subtractions is used to form convergent integral relations between the phase velocity and the attenuation coefficient. When the method of subtractions is applied in the usual manner, the integrands in the relations become unnecessarily complicated. In this work, an expanded form of the subtracted relations is presented, which is essentially a truncated Taylor series expansion of the Hilbert transforms. The implementation of the relations only requires the explicit evaluation of two simply expressed integrals involving the Hilbert transform kernel. These two integrals determine the values of the other terms in the subtracted relations, demonstrating the computational efficiency of the technique. The method is illustrated analytically through its application to power-law attenuation coefficients and its associated dispersion, which are observed in a wide variety of materials. This approach explicitly shows the central role of the Hilbert transform kernel in the KK relations, which can become obscured in other formulations.

  19. Subtraction of beam-associated background in R measurement

    CERN Document Server

    Yan Wen Biao; Chi Shao Peng; Huang Guang Shun; Zhang Lei; Zhang Li; Zhao Zheng Gu; Dai Yu Mei; Li Hui; Wang Zhi Yong

    2002-01-01

    Using R scan data collected at BES II detector, the authors study the character of beam-associated background. The authors use the method of f factor and the fitting of event vertices to subtract the residual beam-associated background. The difference between the R values obtained by using these two methods is between 0.3% and 2.3%

  20. Addition and Subtraction by Students with Down Syndrome

    Science.gov (United States)

    Herrera, Aurelia Noda; Bruno, Alicia; Gonzalez, Carina; Moreno, Lorenzo; Sanabria, Hilda

    2011-01-01

    We present a research report on addition and subtraction conducted with Down syndrome students between the ages of 12 and 31. We interviewed a group of students with Down syndrome who executed algorithms and solved problems using specific materials and paper and pencil. The results show that students with Down syndrome progress through the same…

  1. "Abuelita" Epistemologies: Counteracting Subtractive Schools in American Education

    Science.gov (United States)

    Gonzales, Sandra M.

    2015-01-01

    This autoethnographic inquiry examines the intersection of elder epistemology and subtractive education, exploring how one "abuelita" countered her granddaughter's divestment of Mexican-ness. I demonstrate how the grandmother used "abuelita" epistemologies to navigate this tension and resist the assimilative pressures felt…

  2. Teaching Children about the Inverse Relation between Addition and Subtraction

    Science.gov (United States)

    Nunes, Terezinha; Bryant, Peter; Hallett, Darcy; Bell, Daniel; Evans, Deborah

    2009-01-01

    Two intervention studies are described. Both were designed to study the effects of teaching children about the inverse relation between addition and subtraction. The interventions were successful with 8-year-old children in Study 1 and to a limited extent with 5-year-old children in Study 2. In Study 1 teaching children about inversion increased…

  3. Addition and Subtraction by Students with Down Syndrome

    Science.gov (United States)

    Herrera, Aurelia Noda; Bruno, Alicia; Gonzalez, Carina; Moreno, Lorenzo; Sanabria, Hilda

    2011-01-01

    We present a research report on addition and subtraction conducted with Down syndrome students between the ages of 12 and 31. We interviewed a group of students with Down syndrome who executed algorithms and solved problems using specific materials and paper and pencil. The results show that students with Down syndrome progress through the same…

  4. Adding and Subtracting Vectors: The Problem with the Arrow Representation

    Science.gov (United States)

    Heckler, Andrew F.; Scaife, Thomas M.

    2015-01-01

    A small number of studies have investigated student understanding of vector addition and subtraction in generic or introductory physics contexts, but in almost all cases the questions posed were in the vector arrow representation. In a series of experiments involving over 1000 students and several semesters, we investigated student understanding…

  5. Children's Understanding of the Addition/Subtraction Complement Principle

    Science.gov (United States)

    Torbeyns, Joke; Peters, Greet; De Smedt, Bert; Ghesquière, Pol; Verschaffel, Lieven

    2016-01-01

    Background: In the last decades, children's understanding of mathematical principles has become an important research topic. Different from the commutativity and inversion principles, only few studies have focused on children's understanding of the addition/subtraction complement principle (if a - b = c, then c + b = a), mainly relying on verbal…

  6. Subtraction-noise projection in gravitational-wave detector networks

    CERN Document Server

    Harms, Jan; Otto, Markus; Priess, Malte

    2008-01-01

    In this paper, we present a successful implementation of a subtraction-noise projection method into a simple, simulated data analysis pipeline of a gravitational-wave search. We investigate the problem to reveal a weak stochastic background signal which is covered by a strong foreground of compact-binary coalescences. The foreground which is estimated by matched filters, has to be subtracted from the data. Even an optimal analysis of foreground signals will leave subtraction noise due to estimation errors of template parameters which may corrupt the measurement of the background signal. The subtraction noise can be removed by a noise projection. We apply our analysis pipeline to the proposed future-generation space-borne Big Bang Observer (BBO) mission which seeks for a stochastic background of primordial GWs in the frequency range $\\sim 0.1-1 $Hz covered by a foreground of black-hole and neutron-star binaries. Our analysis is based on a simulation code which provides a dynamical model of a time-delay interfe...

  7. Quantitative analysis of alveolar bone change following implant placement using intraoral radiographic subtraction

    Energy Technology Data Exchange (ETDEWEB)

    Kimura, Hiroyuki; Kanda, Shigenobu [Kyushu Univ., Fukuoka (Japan). Graduate School of Dental Science; Tanaka, Takemasa [Kyushu Univ., Fukuoka (Japan). Dental Hospital

    2002-12-01

    The purpose of this study was to develop a procedure for quantitative analysis using intraoral radiographs of alveolar bone after placement of dental implants and to consider the validity of the method. We evaluated the ten patients (2 males and 8 females, average age: 48.4 years-old), who were treated with dental implant operation in the site of mandibular molar region, since October of 1999 until September of 2000 in Kimura Dental Clinic (Kumamoto, Japan). We evaluated the intraoral radiographs taken pre- and post- operatively and at follow-up examination. To detect alveolar bone change on radiograph, we adopted the digital subtraction method. Although the radiographs were taken under an ordinary technique with cone indicator, we did not apply the standardized technique with fixing material customized for each patient. Therefore, we used geometric correction and density compensation before subtraction. We assessed the basic statistical values (mean, variance, kurtosis and skewness) of the region of interest (ROI) of the subtracted images. Also, we noted PPD (probing pocket depth) and BOP (bleeding on probing) at each site as indicators of clinical findings and all implanted sites were classified according to the PPD or BOP, i.e. PPD increased group ''PPD (+)'' and PPD stable group ''PPD (-)'', likewise BOP positive group ''BOP (+)'' and negative group ''BOP (-)''. We considered the statistical values of ROI in each group and compared these findings. Mean and variance values of PPD (+) were higher than those of PPD (-) and there was a significant difference in mean value (p=0.031). Similarly, mean and variance values of BOP (+) were statistically higher than those of BOP (-) (p=0.041 and p=0.0087, respectively). Concerning kurtosis and skewness, there was no difference between PPD (+) and PPD (-), or between BOP (+) and BOP (-). Using our method, the radiographs taken for follow

  8. Digital Subtraction Phonocardiography (DSP applied to the detection and characterization of heart murmurs

    Directory of Open Access Journals (Sweden)

    Ali Akbari Mohammad

    2011-12-01

    Full Text Available Abstract Background During the cardiac cycle, the heart normally produces repeatable physiological sounds. However, under pathologic conditions, such as with heart valve stenosis or a ventricular septal defect, blood flow turbulence leads to the production of additional sounds, called murmurs. Murmurs are random in nature, while the underlying heart sounds are not (being deterministic. Innovation We show that a new analytical technique, which we call Digital Subtraction Phonocardiography (DSP, can be used to separate the random murmur component of the phonocardiogram from the underlying deterministic heart sounds. Methods We digitally recorded the phonocardiogram from the anterior chest wall in 60 infants and adults using a high-speed USB interface and the program Gold Wave http://www.goldwave.com. The recordings included individuals with cardiac structural disease as well as recordings from normal individuals and from individuals with innocent heart murmurs. Digital Subtraction Analysis of the signal was performed using a custom computer program called Murmurgram. In essence, this program subtracts the recorded sound from two adjacent cardiac cycles to produce a difference signal, herein called a "murmurgram". Other software used included Spectrogram (Version 16, GoldWave (Version 5.55 as well as custom MATLAB code. Results Our preliminary data is presented as a series of eight cases. These cases show how advanced signal processing techniques can be used to separate heart sounds from murmurs. Note that these results are preliminary in that normal ranges for obtained test results have not yet been established. Conclusions Cardiac murmurs can be separated from underlying deterministic heart sounds using DSP. DSP has the potential to become a reliable and economical new diagnostic approach to screening for structural heart disease. However, DSP must be further evaluated in a large series of patients with well-characterized pathology to determine

  9. Digital Subtraction Phonocardiography (DSP) applied to the detection and characterization of heart murmurs.

    Science.gov (United States)

    Akbari, Mohammad Ali; Hassani, Kamran; Doyle, John D; Navidbakhsh, Mahdi; Sangargir, Maryam; Bajelani, Kourosh; Ahmadi, Zahra Sadat

    2011-12-20

    During the cardiac cycle, the heart normally produces repeatable physiological sounds. However, under pathologic conditions, such as with heart valve stenosis or a ventricular septal defect, blood flow turbulence leads to the production of additional sounds, called murmurs. Murmurs are random in nature, while the underlying heart sounds are not (being deterministic). We show that a new analytical technique, which we call Digital Subtraction Phonocardiography (DSP), can be used to separate the random murmur component of the phonocardiogram from the underlying deterministic heart sounds. We digitally recorded the phonocardiogram from the anterior chest wall in 60 infants and adults using a high-speed USB interface and the program Gold Wave http://www.goldwave.com. The recordings included individuals with cardiac structural disease as well as recordings from normal individuals and from individuals with innocent heart murmurs. Digital Subtraction Analysis of the signal was performed using a custom computer program called Murmurgram. In essence, this program subtracts the recorded sound from two adjacent cardiac cycles to produce a difference signal, herein called a "murmurgram". Other software used included Spectrogram (Version 16), GoldWave (Version 5.55) as well as custom MATLAB code. Our preliminary data is presented as a series of eight cases. These cases show how advanced signal processing techniques can be used to separate heart sounds from murmurs. Note that these results are preliminary in that normal ranges for obtained test results have not yet been established. Cardiac murmurs can be separated from underlying deterministic heart sounds using DSP. DSP has the potential to become a reliable and economical new diagnostic approach to screening for structural heart disease. However, DSP must be further evaluated in a large series of patients with well-characterized pathology to determine its clinical potential.

  10. A method for dynamic subtraction MR imaging of the liver

    Directory of Open Access Journals (Sweden)

    Setti Ernesto

    2006-06-01

    Full Text Available Abstract Background Subtraction of Dynamic Contrast-Enhanced 3D Magnetic Resonance (DCE-MR volumes can result in images that depict and accurately characterize a variety of liver lesions. However, the diagnostic utility of subtraction images depends on the extent of co-registration between non-enhanced and enhanced volumes. Movement of liver structures during acquisition must be corrected prior to subtraction. Currently available methods are computer intensive. We report a new method for the dynamic subtraction of MR liver images that does not require excessive computer time. Methods Nineteen consecutive patients (median age 45 years; range 37–67 were evaluated by VIBE T1-weighted sequences (TR 5.2 ms, TE 2.6 ms, flip angle 20°, slice thickness 1.5 mm acquired before and 45s after contrast injection. Acquisition parameters were optimized for best portal system enhancement. Pre and post-contrast liver volumes were realigned using our 3D registration method which combines: (a rigid 3D translation using maximization of normalized mutual information (NMI, and (b fast 2D non-rigid registration which employs a complex discrete wavelet transform algorithm to maximize pixel phase correlation and perform multiresolution analysis. Registration performance was assessed quantitatively by NMI. Results The new registration procedure was able to realign liver structures in all 19 patients. NMI increased by about 8% after rigid registration (native vs. rigid registration 0.073 ± 0.031 vs. 0.078 ± 0.031, n.s., paired t-test and by a further 23% (0.096 ± 0.035 vs. 0.078 ± 0.031, p t-test after non-rigid realignment. The overall average NMI increase was 31%. Conclusion This new method for realigning dynamic contrast-enhanced 3D MR volumes of liver leads to subtraction images that enhance diagnostic possibilities for liver lesions.

  11. Lung fibrosis: drug screening and disease biomarker identification with a lung slice culture model and subtracted cDNA Library.

    Science.gov (United States)

    Guo, Tong; Lok, Ka Yee; Yu, Changhe; Li, Zhuo

    2014-09-01

    Pulmonary fibrosis is a progressive and irreversible disorder with no appropriate cure. A practical and effective experimental model that recapitulates the disease will greatly benefit the research community and, ultimately, patients. In this study, we tested the lung slice culture (LSC) system for its potential use in drug screening and disease biomarker identification. Fibrosis was induced by treating rat lung slices with 1ng/ml TGF-β1 and 2.5μM CdCl2, quantified by measuring the content of hydroxyproline, and confirmed by detecting the expression of collagen type III alpha 1 (Col3α1) and connective tissue growth factor (CTGF) genes. The anti-fibrotic effects of pirfenidone, spironolactone and eplerenone were assessed by their capability to reduce hydroxyproline content. A subtractive hybridisation technique was used to create two cDNA libraries (subtracted and unsubtracted) from lung slices. The housekeeping gene glyceraldehyde-3-phosphate dehydrogenase (GAPDH) was employed to assess the subtraction efficiency of the subtracted cDNA library. Clones from the two libraries were sequenced and the genes were identified by performing a BLAST search on the NCBI GenBank database. Furthermore, the relevance of the genes to fibrosis formation was verified. The results presented here show that fibrosis was effectively induced in cultured lung slices, which exhibited significantly elevated levels of hydroxyproline and Col3α1/CTGF gene expression. Several inhibitors have demonstrated their anti-fibrotic effects by significantly reducing hydroxyproline content. The subtracted cDNA library, which was enriched for differentially expressed genes, was used to successfully identify genes associated with fibrosis. Collectively, the results indicate that our LSC system is an effective model for the screening of drug candidates and for disease biomarker identification.

  12. The potential for neurovascular intravenous angiography using K-edge digital subtraction angiography

    Science.gov (United States)

    Schültke, E.; Fiedler, S.; Kelly, M.; Griebel, R.; Juurlink, B.; LeDuc, G.; Estève, F.; Le Bas, J.-F.; Renier, M.; Nemoz, C.; Meguro, K.

    2005-08-01

    Background: Catheterization of small-caliber blood vessels in the central nervous system can be extremely challenging. Alternatively, intravenous (i.v.) administration of contrast agent is minimally invasive and therefore carries a much lower risk for the patient. With conventional X-ray equipment, volumes of contrast agent that could be safely administered to the patient do not allow acquisition of high-quality images after i.v. injection, because the contrast bolus is extremely diluted by passage through the heart. However, synchrotron-based digital K-edge subtraction angiography does allow acquisition of high-quality images after i.v. administration of relatively small doses of contrast agent. Materials and methods: Eight adult male New Zealand rabbits were used for our experiments. Animals were submitted to both angiography with conventional X-ray equipment and synchrotron-based digital subtraction angiography. Results: With conventional X-ray equipment, no contrast was seen in either cerebral or spinal blood vessels after i.v. injection of iodinated contrast agent. However, using K-edge digital subtraction angiography, as little as 1 ml iodinated contrast agent, when administered as i.v. bolus, yielded images of small-caliber blood vessels in the central nervous system (both brain and spinal cord). Conclusions: If it would be possible to image blood vessels of the same diameter in the central nervous system of human patients, the synchrotron-based technique could yield high-quality images at a significantly lower risk for the patient than conventional X-ray imaging. Images could be acquired where catheterization of feeding blood vessels has proven impossible.

  13. Dixon-type and subtraction-type contrast-enhanced magnetic resonance angiography: A theoretical and experimental comparison of SNR and CNR.

    Science.gov (United States)

    Stinson, Eric G; Trzasko, Joshua D; Weavers, Paul T; Riederer, Stephen J

    2014-07-17

    The purpose of this work is to compare the behavior of the signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) in contrast-enhanced MR angiography with background suppression performed by either a Dixon-type or subtraction-type method. Theoretical expressions for the SNR and CNR for both background suppression techniques were derived. The theoretical Dixon:subtraction SNR and CNR ratios were compared to empirical ratios measured from phantom and in vivo studies for Dixon techniques utilizing one, two, and three echoes. Specifically, the SNR and CNR ratios were compared as the concentration of contrast material in the blood changed. Empirical measurements of the SNR and CNR ratios compared favorably with the ratios predicted by theory. As the contrast concentration was reduced, the SNR advantage of the Dixon techniques increased asymptotically. In the ideal case, the SNR improvement over subtraction contrast-enhanced MR angiography was at least twofold for one- and two-echo Dixon techniques and at least a factor of 6 for the three-echo Dixon technique. Expressions showing a contrast concentration-dependent SNR and CNR improvement of at least a factor of two when Dixon-type contrast-enhanced MR angiography is used in place of subtraction-type contrast-enhanced MR angiography were derived and validated with phantom and in vivo experiments. Magn Reson Med, 2014. © 2014 Wiley Periodicals, Inc. Copyright © 2014 Wiley Periodicals, Inc.

  14. Subtraction of Positive and Negative Numbers: The Difference and Completion Approaches with Chips

    Science.gov (United States)

    Flores, Alfinio

    2008-01-01

    Diverse contexts such as "take away," comparison," and "completion" give rise to subtraction problems. The take-away interpretation of subtraction has been explored using two-colored chips to help students understand addition and subtraction of integers. This article illustrates how the difference and completion (or missing addend) interpretations…

  15. BBO and the Neutron-Star-Binary Subtraction Problem

    CERN Document Server

    Cutler, C

    2006-01-01

    The Big Bang Observer (BBO) is a proposed space-based gravitational-wave (GW) mission designed primarily to search for an inflation-generated GW background in the frequency range 0.1-1 Hz. The major astrophysical foreground in this range is gravitational radiation from inspiraling compact binaries. This foreground is expected to be much larger than the inflation-generated background, so to accomplish its main goal, BBO must be sensitive enough to identify and subtract out practically all such binaries in the observable universe. It is somewhat subtle to decide whether BBO's current baseline design is sufficiently sensitive for this task, since, at least initially, the dominant noise source impeding identification of any one binary is confusion noise from all the others. Here we present a self-consistent scheme for deciding whether BBO's baseline design is indeed adequate for subtracting out the binary foreground. We conclude that the current baseline should be sufficient. However if BBO's instrumental sensiti...

  16. ZAP -- Enhanced PCA Sky Subtraction for Integral Field Spectroscopy

    CERN Document Server

    Soto, Kurt T; Bacon, Roland; Richard, Johan; Conseil, Simon

    2016-01-01

    We introduce Zurich Atmosphere Purge (ZAP), an approach to sky subtraction based on principal component analysis (PCA) that we have developed for the Multi Unit Spectrographic Explorer (MUSE) integral field spectrograph. ZAP employs filtering and data segmentation to enhance the inherent capabilities of PCA for sky subtraction. Extensive testing shows that ZAP reduces sky emission residuals while robustly preserving the flux and line shapes of astronomical sources. The method works in a variety of observational situations from sparse fields with a low density of sources to filled fields in which the target source fills the field of view. With the inclusion of both of these situations the method is generally applicable to many different science cases and should also be useful for other instrumentation. ZAP is available for download at http://muse-vlt.eu/science/tools.

  17. Direct Imaging of Exoplanets Without Background Subtraction: Implications for ELTs

    CERN Document Server

    Frazin, Richard A

    2015-01-01

    The ultra-high contrast capability required to form images of other solar systems is arguably the highest-profile challenge in astronomy today. The current high-contrast imaging efforts all require background subtraction to separate the planetary image from the image of the host star. Background estimation is difficult due to the presence of non-common path aberrations (NCPAs) that change with time. The only major source of information that is not being utilized by current efforts is the random encoding of the planetary image and the NCPAs by the atmosphere on millisecond time-scales. Here, a method that utilizes this information in order to avoid background subtraction altogether is proposed. This new paradigm will allow simultaneous estimation of the time-dependent NCPAs and the planetary image via rigorous statistical inference procedures. These procedures are fully compatible with other information sources, such as diurnal field rotation and spectral diversity. Given the open-ended nature of the backgroun...

  18. An Adaptive Background Subtraction Method Based on Kernel Density Estimation

    Directory of Open Access Journals (Sweden)

    Mignon Park

    2012-09-01

    Full Text Available In this paper, a pixel-based background modeling method, which uses nonparametric kernel density estimation, is proposed. To reduce the burden of image storage, we modify the original KDE method by using the first frame to initialize it and update it subsequently at every frame by controlling the learning rate according to the situations. We apply an adaptive threshold method based on image changes to effectively subtract the dynamic backgrounds. The devised scheme allows the proposed method to automatically adapt to various environments and effectively extract the foreground. The method presented here exhibits good performance and is suitable for dynamic background environments. The algorithm is tested on various video sequences and compared with other state-of-the-art background subtraction methods so as to verify its performance.

  19. Increasing entanglement between Gaussian states by coherent photon subtraction.

    Science.gov (United States)

    Ourjoumtsev, Alexei; Dantan, Aurélien; Tualle-Brouri, Rosa; Grangier, Philippe

    2007-01-19

    We experimentally demonstrate that the entanglement between Gaussian entangled states can be increased by non-Gaussian operations. Coherent subtraction of single photons from Gaussian quadrature-entangled light pulses, created by a nondegenerate parametric amplifier, produces delocalized states with negative Wigner functions and complex structures more entangled than the initial states in terms of negativity. The experimental results are in very good agreement with the theoretical predictions.

  20. Increasing entanglement between Gaussian states by coherent photon subtraction

    CERN Document Server

    Ourjoumtsev, A; Tualle-Brouri, R; Grangier, P; Ourjoumtsev, Alexei; Dantan, Aurelien; Tualle-Brouri, Rosa; Grangier, Philippe

    2006-01-01

    We experimentally demonstrate that the entanglement between Gaussian entangled states can be increased by non-Gaussian operations. Coherent subtraction of single photons from Gaussian quadrature-entangled light pulses, created by a non-degenerate parametric amplifier, produces delocalized "Schroedinger kitten" states with complex negative Wigner functions, more entangled than the initial states in terms of negativity. The experimental results are in very good agreement with the theoretical predictions.

  1. Manufacturability analysis to combine additive and subtractive processes

    OpenAIRE

    Kerbrat, Olivier; MOGNOL, Pascal; Hascoët, Jean-Yves

    2010-01-01

    International audience; Purpose - The purpose of this paper is to propose a methodology to estimate manufacturing complexity for both machining and layered manufacturing. The goal is to take into account manufacturing constraints at design stage in order to realize tools (dies and molds) by a combination of a subtractive process (high-speed machining) and an additive process (selective laser sintering). Design/methodology/approach - Manufacturability indexes are defined and calculated from th...

  2. Digital subtraction angiography in pediatric cerebrovascular occlusive disease

    Energy Technology Data Exchange (ETDEWEB)

    Faerber, E.N.; Griska, L.A.B.; Swartz, J.D.; Capitanio, M.A.; Popky, G.L.

    1984-08-01

    While conventional angiography has been used to demonstrate cerebrovascular occlusive disease in the past, digital subtraction angiography (DSA) is capable of showing progressive vascular involvement with ease, simplicity, and extremely low morbidity, making it particularly well suited for children and outpatients either alone or coordinated with computed tomography. The authors discuss the usefulness and advantages of DSA as demonstrated in 7 infants and children with hemiplegia, 4 of whom had sickle-cell disease.

  3. Manufacturability analysis to combine additive and subtractive processes

    OpenAIRE

    Kerbrat, Olivier; Mognol, Pascal; Hascoët, Jean-Yves

    2010-01-01

    International audience; Purpose - The purpose of this paper is to propose a methodology to estimate manufacturing complexity for both machining and layered manufacturing. The goal is to take into account manufacturing constraints at design stage in order to realize tools (dies and molds) by a combination of a subtractive process (high-speed machining) and an additive process (selective laser sintering). Design/methodology/approach - Manufacturability indexes are defined and calculated from th...

  4. Subtractive Renormalization Group Invariance: Pionless EFT at NLO

    Science.gov (United States)

    Timóteo, Varese S.; Szpigel, Sérgio; Durães, Francisco O.

    2010-11-01

    We show some results concerning the renormalization group (RG) invariance of the nucleon-nucleon (NN) interaction in pionless effective field theory at next-to-leading order (NLO), using a non-relativistic Callan-Symanzik equation (NRCS) for the driving term of the Lippmann-Schwinger (LS) equation with three recursive subtractions. The phase-shifts obtained for the RG evolved potential are same as those for the original potential, apart from relative differences of order 10-15.

  5. Wavelength Self-Calibration and Sky Subtraction for Fabry-Perot Interferometers: Applications to OSIRIS

    CERN Document Server

    Weinzirl, Tim; Bamford, Steven P; del Pino, Bruno Rodriguez; Gray, Meghan E; Chies-Santos, Ana L

    2015-01-01

    We describe techniques concerning wavelength calibration and sky subtraction to maximise the scientific utility of data from tunable filter instruments. While we specifically address data from the Optical System for Imaging and low Resolution Integrated Spectroscopy instrument (OSIRIS) on the 10.4~m Gran Telescopio Canarias telescope, our discussion is generalisable to data from other tunable filter instruments. A key aspect of our methodology is a coordinate transformation to polar coordinates, which simplifies matters when the tunable filter data is circularly symmetric around the optical centre. First, we present a method for rectifying inaccuracies in the wavelength calibration using OH sky emission rings. Using this technique, we improve the absolute wavelength calibration from an accuracy of 5 Angstroms to 1 Angstrom, equivalent to ~7% of our instrumental resolution, for 95% of our data. Then, we discuss a new way to estimate the background sky emission by median filtering in polar coordinates. This met...

  6. N-jettiness Subtractions for NNLO QCD Calculations

    CERN Document Server

    Gaunt, Jonathan; Tackmann, Frank J; Walsh, Jonathan R

    2015-01-01

    We present a subtraction method utilizing the N-jettiness observable, Tau_N, to perform QCD calculations for arbitrary processes at next-to-next-to-leading order (NNLO). Our method employs soft-collinear effective theory (SCET) to determine the IR singular contributions of N-jet cross sections for Tau_N -> 0, and uses these to construct suitable Tau_N-subtractions. The construction is systematic and economic, due to being based on a physical observable. The resulting NNLO calculation is fully differential and in a form directly suitable for combining with resummation and parton showers. We explain in detail the application to processes with an arbitrary number of massless partons at lepton and hadron colliders together with the required external inputs in the form of QCD amplitudes and lower-order calculations. We provide explicit expressions for the Tau_N-subtractions at NLO and NNLO. The required ingredients are fully known at NLO, and at NNLO for processes with two external QCD partons. The remaining NNLO ...

  7. Addition and subtraction in wild New Zealand robins.

    Science.gov (United States)

    Garland, Alexis; Low, Jason

    2014-11-01

    This experiment aimed to investigate proto-arithmetic ability in a wild population of New Zealand robins. We investigated numerical competence from the context of computation: behavioural responses to arithmetic operations over small numbers of prey objects (mealworms). Robins' behavioural responses (such as search time) to the simple addition and subtraction problems presented in a Violation of Expectancy (VoE) paradigm were measured. Either a congruent (expected) or incongruent (unexpected) quantity of food items were hidden in a trap door out of view of the subject. Within view of the subject, a quantity of items were added into (and in some cases subtracted from) the apparatus which was either the same as that hidden, or different. Robins were then allowed them to find a quantity that either preserved or violated addition and subtraction outcomes. Robins searched around the apparatus longer when presented with an incongruent scenario violating arithmetic rules, demonstrating potential proto-arithmetic awareness of changes in prey quantity. This article is part of a Special Issue entitled: Cognition in the wild.

  8. Genome subtraction for novel target definition in Salmonella typhi.

    Science.gov (United States)

    Rathi, Bhawna; Sarangi, Aditya N; Trivedi, Nidhi

    2009-10-11

    Large genomic sequencing projects of pathogens as well as human genome leads to immense genomic and proteomic data which would be very beneficial for the novel target identification in pathogens. Subtractive genomic approach is one of the most useful strategies helpful in identification of potential targets. The approach works by subtracting the genes or proteins homologous to both host and the pathogen and identify those set of gene or proteins which are essential for the pathogen and are exclusively present in the pathogen. Subtractive genomic approach is employed to identify novel target in salmonella typhi. The pathogen has 4718 proteins out of which 300 are found to be essential (" indispensable to support cellular life") in the pathogen with no human homolog. Metabolic pathway analyses of these 300 essential proteins revealed that 149 proteins are exclusively involved in several metabolic pathway of S. typhi. 8 metabolic pathways are found to be present exclusively in the pathogen comprising of 27 enzymes unique to the pathogen. Thus, these 27 proteins may serve as prospective drug targets. Sub-cellular localization prediction of the 300 essential proteins was done which reveals that 11 proteins lie on the outer membrane of the pathogen which could be probable vaccine candidates.

  9. A Monte Carlo simulation study of an improved K-edge log-subtraction X-ray imaging using a photon counting CdTe detector

    Science.gov (United States)

    Lee, Youngjin; Lee, Amy Candy; Kim, Hee-Joung

    2016-09-01

    Recently, significant effort has been spent on the development of photons counting detector (PCD) based on a CdTe for applications in X-ray imaging system. The motivation of developing PCDs is higher image quality. Especially, the K-edge subtraction (KES) imaging technique using a PCD is able to improve image quality and useful for increasing the contrast resolution of a target material by utilizing contrast agent. Based on above-mentioned technique, we presented an idea for an improved K-edge log-subtraction (KELS) imaging technique. The KELS imaging technique based on the PCDs can be realized by using different subtraction energy width of the energy window. In this study, the effects of the KELS imaging technique and subtraction energy width of the energy window was investigated with respect to the contrast, standard deviation, and CNR with a Monte Carlo simulation. We simulated the PCD X-ray imaging system based on a CdTe and polymethylmethacrylate (PMMA) phantom which consists of the various iodine contrast agents. To acquired KELS images, images of the phantom using above and below the iodine contrast agent K-edge absorption energy (33.2 keV) have been acquired at different energy range. According to the results, the contrast and standard deviation were decreased, when subtraction energy width of the energy window is increased. Also, the CNR using a KELS imaging technique is higher than that of the images acquired by using whole energy range. Especially, the maximum differences of CNR between whole energy range and KELS images using a 1, 2, and 3 mm diameter iodine contrast agent were acquired 11.33, 8.73, and 8.29 times, respectively. Additionally, the optimum subtraction energy width of the energy window can be acquired at 5, 4, and 3 keV for the 1, 2, and 3 mm diameter iodine contrast agent, respectively. In conclusion, we successfully established an improved KELS imaging technique and optimized subtraction energy width of the energy window, and based on

  10. A Monte Carlo simulation study of an improved K-edge log-subtraction X-ray imaging using a photon counting CdTe detector

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Youngjin, E-mail: radioyoungj@gmail.com [Department of Radiological Science, Eulji University, 553, Sanseong-daero, Sujeong-gu, Seongnam-si, Gyeonggi-do (Korea, Republic of); Lee, Amy Candy [Department of Mathematics and Statistics, McGill University (Canada); Kim, Hee-Joung [Department of Radiological Science and Radiation Convergence Engineering, Yonsei University (Korea, Republic of)

    2016-09-11

    Recently, significant effort has been spent on the development of photons counting detector (PCD) based on a CdTe for applications in X-ray imaging system. The motivation of developing PCDs is higher image quality. Especially, the K-edge subtraction (KES) imaging technique using a PCD is able to improve image quality and useful for increasing the contrast resolution of a target material by utilizing contrast agent. Based on above-mentioned technique, we presented an idea for an improved K-edge log-subtraction (KELS) imaging technique. The KELS imaging technique based on the PCDs can be realized by using different subtraction energy width of the energy window. In this study, the effects of the KELS imaging technique and subtraction energy width of the energy window was investigated with respect to the contrast, standard deviation, and CNR with a Monte Carlo simulation. We simulated the PCD X-ray imaging system based on a CdTe and polymethylmethacrylate (PMMA) phantom which consists of the various iodine contrast agents. To acquired KELS images, images of the phantom using above and below the iodine contrast agent K-edge absorption energy (33.2 keV) have been acquired at different energy range. According to the results, the contrast and standard deviation were decreased, when subtraction energy width of the energy window is increased. Also, the CNR using a KELS imaging technique is higher than that of the images acquired by using whole energy range. Especially, the maximum differences of CNR between whole energy range and KELS images using a 1, 2, and 3 mm diameter iodine contrast agent were acquired 11.33, 8.73, and 8.29 times, respectively. Additionally, the optimum subtraction energy width of the energy window can be acquired at 5, 4, and 3 keV for the 1, 2, and 3 mm diameter iodine contrast agent, respectively. In conclusion, we successfully established an improved KELS imaging technique and optimized subtraction energy width of the energy window, and based on

  11. Assessment of vasospasm in experimental subarachnoid hemorrhage in rats by selective biplane digital subtraction angiography

    Energy Technology Data Exchange (ETDEWEB)

    Weidauer, Stefan; Dettmann, Edgar; Zanella, Friedhelm E. [University of Frankfurt, Institute of Neuroradiology, Frankfurt (Germany); Vatter, Hartmut; Seifert, Volker [University of Frankfurt, Clinic of Neurosurgery, Frankfurt (Germany)

    2006-03-15

    Although the rat subarachnoid hemorrhage model is well established in vasospasm research, the angiographic evaluation is difficult due to the animal's small size. For this reason, the aim of the study was to develop a standardized angiographic examination technique without additional complex equipment. Under general anesthesia, 11 Sprague-Dawley rats underwent selective cerebral digital subtraction angiography using a 0.3 mm focal spot and a 2.0-fold linear magnification. Five animals had experimental subarachnoid hemorrhage according to the ''double-hemorrhage'' model. Comparison with the intraarterial tip of the microcatheter enabled calibration of the vessel lumen. The diameter of the normal basilar artery (n=6) was 0.34{+-}0.03 mm (mean{+-}SD), whereas delayed vasospastic constriction (mean 6.2 days) caused a reduction in diameter of 32.4% (0.23{+-}0.09 mm) as well as impaired collateral blood flow via the posterior communicating artery and anterior spinal artery. Histological examination of sections stained with hematoxylin and eosin under a light microscope confirmed vasospasm. In conclusion, biplane digital subtraction angiography allows precise and reliable evaluation of arterial diameter reduction and hemodynamic parameters in a rat vasospasm model. However, further investigation is required for assessment of vasoactive drugs, e.g., endothelin receptor antagonists. (orig.)

  12. Construction of Hypericin Gland-Specific cDNA Library via Suppression Subtractive Hybridization.

    Science.gov (United States)

    Singh, Rupesh Kumar; Hou, Weina; Franklin, Gregory

    2016-01-01

    Hypericin, an important determinant of the pharmacological properties of the genus Hypericum, is considered as a major molecule for drug development. However, biosynthesis and accumulation of hypericin is not well understood. Identification of genes differentially expressed in tissues with and without hypericin accumulation is a useful strategy to elucidate the mechanisms underlying the development of the dark glands and hypericin biosynthesis. Suppression Subtractive Hybridization (SSH) is a unique method for PCR-based amplification of specific cDNA fragments that differ between a control (driver) and experimental (tester) transcriptome. This technique relies on the removal of dsDNA formed by hybridization between a control and test sample, thus eliminating cDNAs of similar abundance, and retaining differentially expressed or variable in sequence cDNAs. In our laboratory we applied this method to identify the genes involved in the development of dark glands and accumulation of hypericin in Hypericum perforatum. Here we describe the complete procedure for the construction of hypericin gland-specific subtracted cDNA library.

  13. Differentially expressed genes of virulent and nonvirulent Entamoeba histolytica strains identified by suppression subtractive hybridization.

    Science.gov (United States)

    Freitas, Michelle A R; Alvarenga, Ângela C; Fernandes, Helen C; Gil, Frederico F; Melo, Maria N; Pesquero, Jorge L; Gomes, Maria A

    2014-01-01

    Entamoeba histolytica is a parasite which presents capacity to degrade tissues and therefore has a pathogenic behavior. As this behavior is not shown by all strains, there have been several studies investigating molecular basis of the cytotoxicity process. Using the suppression subtractive hybridization (SSH) technique, differential gene expressions of two E. histolytica strains, one virulent (EGG) and one nonvirulent (452), have been analyzed with the purpose of isolating genes which may be involved with amoebic virulence. Nine cDNA fragments presenting high homology with E. histolytica previously sequenced genes were subtracted. Of these, four genes were confirmed by RT-PCR. Two coding for hypothetical proteins, one for a cysteine-rich protein, expressed only in the virulent strain, EGG and another one, coding for grainin 2 protein, exclusive from 452 strain. This study provided new insight into the proteins differences in the virulent and nonvirulent E. histolytica strains. We believe that further studies with these proteins may prove association of them with tissue damage, providing new perceptions to improve treatment or diagnosis of the invasive disease.

  14. Carbon dioxide digital subtraction angiography in percutaneous sclerotherapy of venous hemangiomas

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jae Hyung; Chung, Jin Wook; Kang, Heung Sik; Han, Man Chung [Seoul National Univ. College of Medicine, Seoul (Korea, Republic of)

    1997-08-01

    To investigate the usefulness of carbon dioxide digital subtraction angiography (CO{sub 2}-DSA) in direct puncture sclerotherapy of venous hemangiomas involving extremities. Direct puncture sclerotherapy was performed in 12 patients with venous hemangioma of extremities. After direct puncture of the venous hemangiomas, 30-50cc of CO{sub 2} was manually injected and digital subtraction angiograms were obtained. If draining vein was visualized, a tourniquet was applied at the proximal site to compress the draining veins. Thereafter, radiopaque embolic materials such as 1:3 mixture of Lipiodol and absolute ethanol or ethanolamine oleate-Lipiodol-Avitene(microfibrillar collagen hemostat) mixture were slowly injected under the fluoroscopic guidance. Rapid injection of large amount of CO{sub 2} enabled the visualization of wide areas of venous hemangiomas in 11 patients. Draining veins were reliably demonstrated in 10 patients and pulmonary embolism of embolic materials was effectively prevented by proximal tourniquet application. Because of radiolucent nature of CO{sub 2} retained in hemangiomas, we could clearly identify the distribution of radiopaque embolic materials under fluoroscopy. Retained CO{sub 2} also could be used as a guide for additional multiple puncture of hemangiomas. There was no systemic symptoms or complications related to CO{sub 2}-DSA. CO{sub 2}-DSA is a convenient, safe and useful angiographic technique in direct puncture sclerotherapy of hemangiomas involving extremities.

  15. Differentially Expressed Genes of Virulent and Nonvirulent Entamoeba histolytica Strains Identified by Suppression Subtractive Hybridization

    Directory of Open Access Journals (Sweden)

    Michelle A. R. Freitas

    2014-01-01

    Full Text Available Entamoeba histolytica is a parasite which presents capacity to degrade tissues and therefore has a pathogenic behavior. As this behavior is not shown by all strains, there have been several studies investigating molecular basis of the cytotoxicity process. Using the suppression subtractive hybridization (SSH technique, differential gene expressions of two E. histolytica strains, one virulent (EGG and one nonvirulent (452, have been analyzed with the purpose of isolating genes which may be involved with amoebic virulence. Nine cDNA fragments presenting high homology with E. histolytica previously sequenced genes were subtracted. Of these, four genes were confirmed by RT-PCR. Two coding for hypothetical proteins, one for a cysteine-rich protein, expressed only in the virulent strain, EGG and another one, coding for grainin 2 protein, exclusive from 452 strain. This study provided new insight into the proteins differences in the virulent and nonvirulent E. histolytica strains. We believe that further studies with these proteins may prove association of them with tissue damage, providing new perceptions to improve treatment or diagnosis of the invasive disease.

  16. Novel method for digital subtraction of tagged stool in virtual colonoscopy

    Science.gov (United States)

    Guendel, Lutz; Suehling, Michael; Eckert, Helmut

    2008-03-01

    Colon cancer is one of the most frequent causes of death. CT colonography is a novel method for the detection of polyps and early cancer. The general principle of CT colonography includes a cathartic bowel preparation. The resulting discomfort for patients leads to limited patient acceptance and therefore to limited cancer detection rates. Reduced bowel preparation, techniques for stool tagging, and electronic cleansing, however, improve the acceptance rates. Hereby, the high density of oral contrast material highlights residual stool and can be digitally removed. Known subtraction methods cause artifacts: additional 3D objects are introduced and small bowel folds are perforated. We propose a new algorithm that is based on the 2 nd derivative of the image data using the Hessian matrix and the following principal axis transform to detect tiny folds which shall not be subtracted together with tagged stool found by a thresholding method. Since the stool is usually not homogenously tagged with contrast media a detection algorithm for island-like structures is incorporated. The interfaces of air-stool level and colon wall are detected by a 3-dimensional difference of Gaussian module. A 3-dimensional filter smoothes the transitions between removed stool and colon tissue. We evaluated the efficacy of the new algorithm with 10 patient data sets. The results showed no introduced artificial objects and no perforated folds. The artifacts at the air-stool and colon tissue-stool transitions are considerably reduced compared to those known from the literature.

  17. Automated Transient Recovery Algorithm using Discrete Zernike Polynomials on Image-Subtracted Data

    Science.gov (United States)

    Ackley, Kendall; Eikenberry, Stephen S.; Klimenko, Sergey

    2016-01-01

    We present an unsupervised algorithm for the automated identification of astrophysical transients recovered through image subtraction techniques. We use a set of discrete Zernike polynomials to decompose and characterize residual energy discovered in the final subtracted image, identifying candidate sources which appear point-like in nature. This work is motivated for use in collaboration with Advanced gravitational wave (GW) interferometers, such as Advanced LIGO and Virgo, where multiwavelength electromagnetic (EM) emission is expected in parallel with gravitational radiation from compact binary object mergers of neutron stars (NS-NS) and stellar-mass black holes (NS-BH). Imaging an EM counterpart coincident with a GW trigger will help to constrain the multi-dimensional GW parameter space as well as aid in the resolution of long-standing astrophysical mysteries, such as the true nature of the progenitor relationship between short-duration GRBs and massive compact binary mergers. We are working on making our method an open-source package optimized for low-latency response for community use during the upcoming era of GW astronomy.

  18. Multi-section CT angiography compared with digital subtraction angiography in diagnosing major arterial hemorrhage in inflammatory pancreatic disease

    Energy Technology Data Exchange (ETDEWEB)

    Hyare, Harpreet [Department of Imaging, University College London Hospitals NHS Foundation Trust, University College Hospital, 235 Euston Road, London NW1 2BU (United Kingdom)]. E-mail: hhyare@doctors.org.uk; Desigan, Sharmini [Department of Imaging, University College London Hospitals NHS Foundation Trust, University College Hospital, 235 Euston Road, London NW1 2BU (United Kingdom); Nicholl, Helen [Department of Imaging, University College London Hospitals NHS Foundation Trust, University College Hospital, 235 Euston Road, London NW1 2BU (United Kingdom); Guiney, Michael J. [Department of Imaging, University College London Hospitals NHS Foundation Trust, University College Hospital, 235 Euston Road, London NW1 2BU (United Kingdom); Brookes, Jocelyn A. [Department of Imaging, University College London Hospitals NHS Foundation Trust, University College Hospital, 235 Euston Road, London NW1 2BU (United Kingdom); Lees, William R. [Department of Imaging, University College London Hospitals NHS Foundation Trust, University College Hospital, 235 Euston Road, London NW1 2BU (United Kingdom)

    2006-08-15

    Purpose: Major arterial hemorrhage is an uncommon but serious complication of pancreatitis with high morbidity and mortality. Digital subtraction angiography (DSA) has long been the gold standard for the detection of a visceral artery pseudoaneurysm or for the site of active bleeding in patients with pancreatitis. Multi-section CT angiography is a minimally invasive technique which can provide high-resolution and high-contrast images of the arterial lumen and wall, with a much lower risk of complication and morbidity compared to DSA. The aim of this study was to determine the accuracy of multi-section CT angiography for the diagnosis of arterial complications of inflammatory pancreatitic disease. Materials and methods: A retrospective analysis of all patients undergoing visceral angiography for major bleeding as a complication of pancreatitis between 1998 and 2004 was performed. Twenty-nine studies in 25 patients (20 males, 5 females) with a mean age of 50.9 years (range 11-67 years) were identified where multi-section CT angiography was performed in the 24 h preceding the digital subtraction angiogram. Results: Digital subtraction angiography detected a pseudoaneurysm or contrast extravasation in 19 studies and no bleeding was demonstrated in 9 studies. CT angiography correctly identified the site and type of bleeding in 18 of the 19 positive studies. CT angiography detected extravasation of contrast in one study that was not demonstrated on digital subtraction angiography. The sensitivity and specificity for multi-section CT angiography for the detection of major arterial bleeding on a background of pancreatitis were 0.947 and 0.900, respectively. Conclusion: Multi-section CT angiography is a sensitive and accurate technique for the detection of major arterial hemorrhage in inflammatory pancreatic disease and should be considered as the first investigation in the management of these patients.

  19. Adding and subtracting vectors: The problem with the arrow representation

    Directory of Open Access Journals (Sweden)

    Andrew F. Heckler

    2015-01-01

    Full Text Available A small number of studies have investigated student understanding of vector addition and subtraction in generic or introductory physics contexts, but in almost all cases the questions posed were in the vector arrow representation. In a series of experiments involving over 1000 students and several semesters, we investigated student understanding of vector addition and subtraction in both the arrow and algebraic notation (using i[over ^], j[over ^], k[over ^] in generic mathematical and physics contexts. First, we replicated a number of previous findings of student difficulties in the arrow format and discovered several additional difficulties, including the finding that different relative arrow orientations can prompt different solution paths and different kinds of mistakes, which suggests that students need to practice with a variety of relative orientations. Most importantly, we found that average performance in the ijk format was typically excellent and often much better than performance in the arrow format in either the generic or physics contexts. Further, while we find that the arrow format tends to prompt students to a more physically intuitive solution path, we also find that, when prompted, student solutions in the ijk format also display significant physical insights into the problem. We also find a hierarchy in correct answering between the two formats, with correct answering in the ijk format being more fundamental than for the arrow format. Overall, the results suggest that many student difficulties with these simple vector problems lie with the arrow representation itself. For instruction, these results imply that introducing the ijk notation (or some equivalent with the arrow notation concurrently may be a very useful way to improve student performance as well as help students to learn physics concepts involving vector addition and subtraction.

  20. Intermediate Palomar Transient Factory: Realtime Image Subtraction Pipeline

    CERN Document Server

    Cao, Yi; Kasliwal, Mansi M

    2016-01-01

    A fast-turnaround pipeline for realtime data reduction plays an essential role in discovering and permitting follow-up observations to young supernovae and fast-evolving transients in modern time-domain surveys. In this paper, we present the realtime image subtraction pipeline in the intermediate Palomar Transient Factory. By using high-performance computing, efficient database, and machine learning algorithms, this pipeline manages to reliably deliver transient candidates within ten minutes of images being taken. Our experience in using high performance computing resources to process big data in astronomy serves as a trailblazer to dealing with data from large-scale time-domain facilities in near future.

  1. Addition and subtraction by students with Down syndrome

    Science.gov (United States)

    Noda Herrera, Aurelia; Bruno, Alicia; González, Carina; Moreno, Lorenzo; Sanabria, Hilda

    2011-01-01

    We present a research report on addition and subtraction conducted with Down syndrome students between the ages of 12 and 31. We interviewed a group of students with Down syndrome who executed algorithms and solved problems using specific materials and paper and pencil. The results show that students with Down syndrome progress through the same procedural levels as those without disabilities though they have difficulties in reaching the most abstract level (numerical facts). The use of fingers or concrete representations (balls) appears as a fundamental process among these students. As for errors, these vary widely depending on the students, and can be attributed mostly to an incomplete knowledge of the decimal number system.

  2. Black hole entropy thermodynamics, statistical-mechanics and subtraction procedure

    CERN Document Server

    Frolov, V P; Zelnikov, A I

    1996-01-01

    The thermodynamical one-loop entropy S^{TD} of a two-dimensional black hole in thermal equilibrium with the massless quantum gas is calculated. It is shown that S^{TD} includes the Bekenstein-Hawking entropy, evaluated for the quantum corrected geometry, and the finite difference of statistical mechanical entropies -Tr\\hat{\\rho}\\ln\\hat{\\rho} for the gas on the black hole and Rindler spaces. This result demonstrates in an explicit form that the relation between thermodynamical and statistical-mechanical entropies of a black hole is non-trivial and requires special subtraction procedure.

  3. Comparing Background Subtraction Algorithms and Method of Car Counting

    CERN Document Server

    Thakur, Gautam S; Hui, Pan; Helmy, Ahmed

    2012-01-01

    In this paper, we compare various image background subtraction algorithms with the ground truth of cars counted. We have given a sample of thousand images, which are the snap shots of current traffic as records at various intersections and highways. We have also counted an approximate number of cars that are visible in these images. In order to ascertain the accuracy of algorithms to be used for the processing of million images, we compare them on many metrics that includes (i) Scalability (ii) Accuracy (iii) Processing time.

  4. Speech enhancement by array crosstalk resistant ANC and spectrum subtraction

    Institute of Scientific and Technical Information of China (English)

    ZENG Qingning; OUYANG Shan

    2008-01-01

    Microphone array-based speech enhancement has great importance for speech com-munications and speech recognition. To reduce the aperture of the microphone array and to increase the effect of the speech enhancement will greatly broaden the application areas of the microphone array. An array crosstalk resistant adaptive noise cancellation method is therefore presented. And then an improved spectral subtraction algorithm is further cascaded to obtain better enhancement results. Theoretic analysis and experiments indicate that the proposed scheme needs only a very small microphone array while it simultaneously achieves a higher SNR improvement. Besides, the proposed scheme can be used in many noisy environments and is easy for real-time implementation.

  5. K-edge digital subtraction imaging based on a dichromatic and compact x-ray source

    Science.gov (United States)

    Sarnelli, A.; Taibi, A.; Tuffanelli, A.; Baldazzi, G.; Bollini, D.; Cabal Rodriguez, A. E.; Gombia, M.; Prino, F.; Ramello, L.; Tomassi, E.; Gambaccini, M.

    2004-07-01

    This work proposes a compact dichromatic imaging system for the application of the K-edge digital subtraction technique based on a conventional x-ray tube and a monochromator system. A quasi-monochromatic x-ray beam at the energy of iodine K-edge is produced by Bragg diffraction on a mosaic crystal. Two thin adjacent beams with energies that bracket the K-edge discontinuity are obtained from the diffracted beam by means of a proper collimation system. They are then detected using an array of Si detectors. A home-made phantom is used to study the image quality as a function of iodine concentration. Signal and signal-to-noise ratio analysis has also been performed. The results are compared with theoretical expectations.

  6. Comparisons of FIR and IIR implementations of a subtraction-based stimulus artifact rejection algorithm.

    Science.gov (United States)

    Azin, Meysam; Chiel, Hillel J; Mohseni, Pedram

    2007-01-01

    Finite impulse response (FIR) and infinite impulse response (IIR) temporal filtering techniques are investigated to assess the feasibility of very-large-scale-integrated (VLSI) implementation of a subtraction-based stimulus artifact rejection (SAR) algorithm in implantable, closed-loop neuroprostheses. The two approaches are compared in terms of their system architectures, overall performances, and the associated computational costs. Pre-recorded neural data from an Aplysia californica are used to demonstrate the functionality of the proposed implementations. Digital building blocks for an FIR-based system are also simulated in a 0.18-microm CMOS technology, showing a total power consumption of IIR-based system can further reduce the required power consumption and die area.

  7. The use of neurovascular ultrasound versus digital subtraction angiography in acute ischemic stroke

    Directory of Open Access Journals (Sweden)

    Marcos C. Lange

    2015-03-01

    Full Text Available Cervical and intracranial arterial evaluation is an important issue for acute ischemic stroke (IS. Objective Compare the use of the neurovascular ultrasound examination (NVUE to digital subtraction angiography (DSA in acute IS patients for diagnosing significant extracranial and intracranial arteriopathy. Method Nonconsecutive patients with IS or transient ischemic attack admitted within 12 hours of the onset of symptoms were evaluated retrospectively. Standardized NVUE and DSA were done in all patients within the first 120 hours of hospital admission. Results Twenty-four patients were included in the study. Compared to DSA, the NVUE demonstrated 94.7% sensitivity and 100% specificity for identifying symptomatic extracranial and/or intracranial arteriopathy. Conclusion The standardized NVUE technique demonstrated high sensitivity and specificity compared to DSA for diagnosing arterial abnormalities in acute IS patients.

  8. K-edge digital subtraction imaging based on a dichromatic and compact x-ray source

    Energy Technology Data Exchange (ETDEWEB)

    Sarnelli, A [Dipartimento di Fisica dell' Universita di Ferrara and INFN Sezione di Ferrara, Via Paradiso 12, I-44100 Ferrara (Italy); Taibi, A [Dipartimento di Fisica dell' Universita di Ferrara and INFN Sezione di Ferrara, Via Paradiso 12, I-44100 Ferrara (Italy); Tuffanelli, A [Dipartimento di Fisica dell' Universita di Ferrara and INFN Sezione di Ferrara, Via Paradiso 12, I-44100 Ferrara (Italy); Baldazzi, G [Dipartimento di Fisica dell' Universita di Bologna and INFN Sezione di Bologna, Viale Berti Pichat 64/2, 40127 Bologna (Italy); Bollini, D [Dipartimento di Fisica dell' Universita di Bologna and INFN Sezione di Bologna, Viale Berti Pichat 64/2, 40127 Bologna (Italy); Rodriguez, A E Cabal [CAEDAN, Havana (Cuba); Gombia, M [Dipartimento di Fisica dell' Universita di Bologna and INFN Sezione di Bologna, Viale Berti Pichat 64/2, 40127 Bologna (Italy); Prino, F [Dipartimento di Scienze e Tecnologie Avanzate, Universita del Piemonte Orientale and INFN Sezione di Alessandria, C.so, Borsalino 54, I-15100 Alessandria (Italy); Ramello, L [Dipartimento di Scienze e Tecnologie Avanzate, Universita del Piemonte Orientale and INFN Sezione di Alessandria, C.so, Borsalino 54, I-15100 Alessandria (Italy); Tomassi, E [Dipartimento di Scienze e Tecnologie Avanzate, Universita del Piemonte Orientale and INFN Sezione di Alessandria, C.so, Borsalino 54, I-15100 Alessandria (Italy); Gambaccini, M [Dipartimento di Fisica dell' Universita di Ferrara and INFN Sezione di Ferrara, Via Paradiso 12, I-44100 Ferrara (Italy)

    2004-07-21

    This work proposes a compact dichromatic imaging system for the application of the K-edge digital subtraction technique based on a conventional x-ray tube and a monochromator system. A quasi-monochromatic x-ray beam at the energy of iodine K-edge is produced by Bragg diffraction on a mosaic crystal. Two thin adjacent beams with energies that bracket the K-edge discontinuity are obtained from the diffracted beam by means of a proper collimation system. They are then detected using an array of Si detectors. A home-made phantom is used to study the image quality as a function of iodine concentration. Signal and signal-to-noise ratio analysis has also been performed. The results are compared with theoretical expectations.

  9. Nested soft-collinear subtractions in NNLO QCD computations

    Energy Technology Data Exchange (ETDEWEB)

    Caola, Fabrizio [CERN, Theoretical Physics Department, Geneva (Switzerland); IPPP, Durham University, Durham (United Kingdom); Melnikov, Kirill; Roentsch, Raoul [Institute for Theoretical Particle Physics, KIT, Karlsruhe (Germany)

    2017-04-15

    We discuss a modification of the next-to-next-to-leading order (NNLO) subtraction scheme based on the residue-improved sector decomposition that reduces the number of double-real emission sectors from five to four. In particular, a sector where energies and angles of unresolved particles vanish in a correlated fashion is redundant and can be discarded. This simple observation allows us to formulate a transparent iterative subtraction procedure for double-real emission contributions, to demonstrate the cancellation of soft and collinear singularities in an explicit and (almost) process-independent way and to write the result of a NNLO calculation in terms of quantities that can be computed in four space-time dimensions. We illustrate this procedure explicitly in the simple case of O(α{sub s}{sup 2}) gluonic corrections to the Drell-Yan process of q anti q annihilation into a lepton pair. We show that this framework leads to fast and numerically stable computation of QCD corrections. (orig.)

  10. Acquisition-related motion compensation for digital subtraction angiography.

    Science.gov (United States)

    Ionasec, Razvan Ioan; Heigl, Benno; Hornegger, Joachim

    2009-06-01

    Subtraction methods in angiography are generally applied in order to enhance the visualization of blood vessels by eliminating bones and surrounding tissues from X-ray images. The main limitation of these methods is the sensitivity to patient movement, which leads to artifacts and reduces the clinical value of the subtraction images. In this paper we present a novel method for rigid motion compensation with primary application to road mapping, frequently used in image-guided interventions. Using the general concept of image-based registration, we optimize the physical position and orientation of the C-arm X-ray device, thought of as the rigid 3D transformation accounting for the patient movement. The registration is carried out using a hierarchical optimization strategy and a similarity measure based on the variance of intensity differences, which has been shown to be most suitable for fluoroscopic images. Performance evaluation demonstrated the capabilities of the proposed approach to compensate for potential intra-operative patient motion, being more resilient to the fundamental problems of pure image-based registration.

  11. Quasi-Normal Modes for Subtracted Rotating and Magnetised Geometries

    CERN Document Server

    Cvetic, M; Saleem, Z H

    2014-01-01

    We obtain explicit separable solutions of the wave equation of massless minimally coupled scalar fields in the subtracted geometry of four-dimensional rotating and Melvin (magnetised) four-charge black holes of the STU model, a consistent truncation of maximally supersymmetric supergravity with four types of electromagnetic fields. These backgrounds possess a hidden SL(2,R) x SL(2,R) x SO(3) symmetry and faithfully model the near horizon geometry of these black holes, but locate them in a confining asymptotically conical box. For each subtracted geometry we obtain two branches of quasi-normal modes, given in terms of hypergeometric functions and spherical harmonics. One branch is over-damped and the other under-damped and they exhibit rotational splitting. No black hole bomb is possible because the Killing field which co-rotates with the horizon is everywhere timelike outside the black hole. A five-dimensional lift of these geometries is given locally by the product of a BTZ black hole with a a two-sphere. Th...

  12. Infinite S-expansion with ideal subtraction and some applications

    Science.gov (United States)

    Peñafiel, D. M.; Ravera, L.

    2017-08-01

    According to the literature, the S-expansion procedure involving a finite semigroup is valid no matter what the structure of the original Lie (super)algebra is; however, when something about the structure of the starting (super)algebra is known and when certain particular conditions are met, the S-expansion method (with its features of resonance and reduction) is able not only to lead to several kinds of expanded (super)algebras but also to reproduce the effects of the standard as well as the generalized Inönü-Wigner contraction. In the present paper, we propose a new prescription for S-expansion, involving an infinite abelian semigroup S(∞ ) and the subtraction of an infinite ideal subalgebra. We show that the subtraction of the infinite ideal subalgebra corresponds to a reduction. Our approach is a generalization of the finite S-expansion procedure presented in the literature, and it offers an alternative view of the generalized Inönü-Wigner contraction. We then show how to write the invariant tensors of the target (super)algebras in terms of those of the starting ones in the infinite S-expansion context presented in this work. We also give some interesting examples of application on algebras and superalgebras.

  13. Once and twice subtracted dispersion relations in the analysis of pi pi amplitudes

    CERN Document Server

    Kaminski, R; Peláez, J R; Ynduráin, F J

    2009-01-01

    Once and twice subtracted crossing symmetric dispersion relations applied to $\\pi\\pi \\to \\pi\\pi$ scattering data are analyzed and compared. Both sets of dispersion relations can be used to test the $\\pi\\pi$ amplitudes in low partial waves up to about 1 GeV. We show how once subtracted dispersion relations can provide stronger constraints for $\\pi\\pi$ amplitudes than twice subtracted ones in the 400 to 1100 MeV range, given the same experimental input.

  14. ViBe: a universal background subtraction algorithm for video sequences.

    Science.gov (United States)

    Barnich, Olivier; Van Droogenbroeck, Marc

    2011-06-01

    This paper presents a technique for motion detection that incorporates several innovative mechanisms. For example, our proposed technique stores, for each pixel, a set of values taken in the past at the same location or in the neighborhood. It then compares this set to the current pixel value in order to determine whether that pixel belongs to the background, and adapts the model by choosing randomly which values to substitute from the background model. This approach differs from those based upon the classical belief that the oldest values should be replaced first. Finally, when the pixel is found to be part of the background, its value is propagated into the background model of a neighboring pixel. We describe our method in full details (including pseudo-code and the parameter values used) and compare it to other background subtraction techniques. Efficiency figures show that our method outperforms recent and proven state-of-the-art methods in terms of both computation speed and detection rate. We also analyze the performance of a downscaled version of our algorithm to the absolute minimum of one comparison and one byte of memory per pixel. It appears that even such a simplified version of our algorithm performs better than mainstream techniques.

  15. Cadmium Subtraction Method for the Active Albedo Neutron Interrogation of Uranium

    Energy Technology Data Exchange (ETDEWEB)

    Worrall, Louise G. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Croft, Stephen [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-02-01

    This report describes work performed under the Next Generation Safeguards Initiative (NGSI) Cadmium Subtraction Project. The project objective was to explore the difference between the traditional cadmium (Cd) ratio signature and a proposed alternative Cd subtraction (or Cd difference) approach. The thinking behind the project was that a Cd subtraction method would provide a more direct measure of multiplication than the existing Cd ratio method. At the same time, it would be relatively insensitive to changes in neutron detection efficiency when properly calibrated. This is the first published experimental comparison and evaluation of the Cd ratio and Cd subtraction methods.

  16. On-sky tests of sky-subtraction methods for fiber-fed spectrographs

    CERN Document Server

    Rodrigues, Myriam; Hammer, Francois; Royer, Frederic; Evans, C J; Puech, Mathieu; Flores, Hector; Guinouard, Isabelle; Causi, Gianluca Li; Disseau, Karen; Yang, Yanbin

    2016-01-01

    We present preliminary results on on-sky test of sky subtraction methods for fiber-fed spectrograph. Using dedicated observation with FLAMES/VLT in I-band, we have tested the accuracy of the sky subtraction for 4 sky subtraction methods: mean sky, closest sky, dual stare and cross-beam switching. The cross beam-switching and dual stare method reach accuracy and precision of the sky subtraction under 1%. In contrast to the commonly held view in the literature, this result points out that fiber-fed spectrographs are adapted for the observations of faint targets.

  17. Multimodality evaluation of dural arteriovenous fistula with CT angiography, MR with arterial spin labeling, and digital subtraction angiography: case report.

    Science.gov (United States)

    Alexander, Matthew; McTaggart, Ryan; Santarelli, Justin; Fischbein, Nancy; Marks, Michael; Zaharchuk, Greg; Do, Huy

    2014-01-01

    Dural arteriovenous fistulae (DAVF) are cerebrovascular lesions with pathologic shunting into the venous system from arterial feeders. Digital subtraction angiography (DSA) has long been considered the gold standard for diagnosis, but advances in noninvasive imaging techniques now play a role in the diagnosis of these complex lesions. Herein, we describe the case of a patient with right-side pulsatile tinnitus and DAVF diagnosed using computed tomography angiography, magnetic resonance with arterial spin labeling, and DSA. Implications for imaging analysis of DAVFs and further research are discussed.

  18. An adaptive demodulation approach for bearing fault detection based on adaptive wavelet filtering and spectral subtraction

    Science.gov (United States)

    Zhang, Yan; Tang, Baoping; Liu, Ziran; Chen, Rengxiang

    2016-02-01

    Fault diagnosis of rolling element bearings is important for improving mechanical system reliability and performance. Vibration signals contain a wealth of complex information useful for state monitoring and fault diagnosis. However, any fault-related impulses in the original signal are often severely tainted by various noises and the interfering vibrations caused by other machine elements. Narrow-band amplitude demodulation has been an effective technique to detect bearing faults by identifying bearing fault characteristic frequencies. To achieve this, the key step is to remove the corrupting noise and interference, and to enhance the weak signatures of the bearing fault. In this paper, a new method based on adaptive wavelet filtering and spectral subtraction is proposed for fault diagnosis in bearings. First, to eliminate the frequency associated with interfering vibrations, the vibration signal is bandpass filtered with a Morlet wavelet filter whose parameters (i.e. center frequency and bandwidth) are selected in separate steps. An alternative and efficient method of determining the center frequency is proposed that utilizes the statistical information contained in the production functions (PFs). The bandwidth parameter is optimized using a local ‘greedy’ scheme along with Shannon wavelet entropy criterion. Then, to further reduce the residual in-band noise in the filtered signal, a spectral subtraction procedure is elaborated after wavelet filtering. Instead of resorting to a reference signal as in the majority of papers in the literature, the new method estimates the power spectral density of the in-band noise from the associated PF. The effectiveness of the proposed method is validated using simulated data, test rig data, and vibration data recorded from the transmission system of a helicopter. The experimental results and comparisons with other methods indicate that the proposed method is an effective approach to detecting the fault-related impulses

  19. Suppression Subtractive Hybridization (SSH) and its modifications in microbiological research.

    Science.gov (United States)

    Huang, Xiaowei; Li, Yunxia; Niu, Qiuhong; Zhang, Keqin

    2007-09-01

    Suppression subtractive hybridization (SSH) is an effective approach to identify the genes that vary in expression levels during different biological processes. It is often used in higher eukaryotes to study the molecular regulation in complex pathogenic progress, such as tumorigenesis and other chronic multigene-associated diseases. Because microbes have relatively smaller genomes compared with eukaryotes, aside from the analysis at the mRNA level, SSH as well as its modifications have been further employed to isolate specific chromosomal locus, study genomic diversity related with exceptional bacterial secondary metabolisms or genes with special microbial function. This review introduces the SSH and its associated methods and focus on their applications to detect specific functional genes or DNA markers in microorganisms.

  20. The Principle of Digital Subtraction Angiography and Radiological Protection

    Science.gov (United States)

    Okamoto, K.; Ito, J.; Sakai, K.; Yoshimura, S.

    2000-01-01

    Summary Recent improvements in x-ray technology have greatly contributed to the advancement of diagnostic imaging. Fluoroscopically guided neurointerventional procedures with digital subtraction angiography (DSΛ) are being performed with increasing frequency as the treatment of choice for a variety of neurovascular diseases. Radiation-induced skin injuries can occur after extended fluoroscopic exposure times, and the injuries have recently been reported. In this article, measured radiation doses at the surface of Rando Phantom with Skin Dose Monitor, and estimated and measured entrance skin doses in patients underwent neurointerventional procedures are reported as well as means of reducing radiation doses absorbed by patients and personnel to avoid occurrence of radiation-induced injuries. PMID:20667218

  1. Analysis of radiohippuran renogram by subtraction of extrarenal radioactivity

    Energy Technology Data Exchange (ETDEWEB)

    Razzak, M.A.; Botti, R.E.; Macintyre, W.J.

    1976-05-01

    A method is presented for the simple, non-computerized analysis of the radiohippuran renogram by subtraction of the extrarenal radioactivity as monitored simultaneously by a detector centered over the manubrium sterni. This method requires the application of a calibration factor, relating the level of radioactivity recorded by the sternal detector to that over each kidney area at the end point of the phase of initial rise on each side separately. The results in 15 normal individuals showed a narrow range of values, indicating a high degree of resolution. Verification of the basis of this method of analysis was obtained by accounting for all of the counting rate as extrarenal sources in the tracings of nephrectomized subjects. A further advantage is that the tracing recorded by the sternal detector may be used to calculate renal blood flow.

  2. Gadobutrol: an alternative contrast agent for digital subtraction dacryocystography

    Energy Technology Data Exchange (ETDEWEB)

    Priebe, M.; Mohr, A.; Brossmann, J.; Heller, M.; Frahm, C. [Department of Diagnostic Radiology, Christian-Albrechts-University of Kiel, Arnold-Heller-Strasse 9, 24105 Kiel (Germany)

    2002-08-01

    We report the application of gadobutrol as a contrast medium for digital subtraction dacryocystography (DS-DCG) in patients with known allergy to iodinated contrast agent. Gadobutrol has the double gadolinium concentration (1.0 mmol/ml) of other gadolinium-based contrast agents. Quality of the DS-DCG images obtained with gadobutrol was comparable to DS-DCG images obtained with iodinated contrast medium. Radiodensity measurements using a micro-CT scanner confirmed a high radiodensity of gadobutrol which was comparable to the radiodensity of iopentol with a iodine concentration of 250 mg/ml and only approximately 20% lower than the radiodensity of iopentol with a concentration of 300 mg/l. Gadobutrol is a well-suited substitute for DS-DCG in patients with allergy to iodinated contrast agents. (orig.)

  3. Value of intravenous digital subtraction angiography for amaurosis fugax

    Energy Technology Data Exchange (ETDEWEB)

    Horio, Shunji; Uchida, Sunao

    1987-07-01

    We performed intravenous digital subtraction angiography (IVDSA) in 12 cases of amaurosis fugax to evaluate the arteries in the head and neck region. We could detect stenosis or irregularity in the arterial wall in 5 cases (46 %). These 5 cases were treated with surgical or medical antiplatelet therapy. Amaurosis fugax disappeared in all treated cases. We also performed IVDSA in 11 cases with obstructive retinal vascular diseases. Stenosis of internal carotid artery was detected in one case (9 %). IVDSA proved thus to be of value in detecting abnormalities of carotid artery and its tributaries. While it is unlikely that IVDSA will replace conventional intraarterial angiography, IVDSA is much safer than direct arterial puncture and does not require admission in hospital.

  4. Background Subtraction with DirichletProcess Mixture Models.

    Science.gov (United States)

    Haines, Tom S F; Tao Xiang

    2014-04-01

    Video analysis often begins with background subtraction. This problem is often approached in two steps-a background model followed by a regularisation scheme. A model of the background allows it to be distinguished on a per-pixel basis from the foreground, whilst the regularisation combines information from adjacent pixels. We present a new method based on Dirichlet process Gaussian mixture models, which are used to estimate per-pixel background distributions. It is followed by probabilistic regularisation. Using a non-parametric Bayesian method allows per-pixel mode counts to be automatically inferred, avoiding over-/under- fitting. We also develop novel model learning algorithms for continuous update of the model in a principled fashion as the scene changes. These key advantages enable us to outperform the state-of-the-art alternatives on four benchmarks.

  5. Hierarchical CodeBook for background subtraction in MRF

    Science.gov (United States)

    Shao, Quan; Tang, Zhixing; Han, Songchen

    2013-11-01

    Foreground detection is the key low-level fundamental work in intelligent video surveillance. This paper proposed a hierarchical background subtraction algorithm consisted of block-based stage and pixel-based stage for it. In block-based stage, obvious backgrounds got detected via block-based CodeBook, leaving spatial relations among suspicious foreground pixels undestroyed. Pixel-based stage further eliminated the left background pixels with the introduction of spatial and temporal relations in a MRF-MAP framework. Then comparative experiments were conducted to evaluate the performance of the scheme in three dimensions - detection accuracy, update speed and memory consumption. Proposed approach possesses the highest detection precision and consumes the second least memories. And the update speed is of real-time level.

  6. Subtraction of "accidentals" and the validity of Bell tests

    CERN Document Server

    Thompson, C H

    1999-01-01

    In some key Bell experiments, including two of the well-known ones by Alain Aspect, 1981-2, it is only after the subtraction of ``accidentals'' from the coincidence counts that we get violations of Bell tests. The data adjustment, producing increases of up to 60% in the test statistics, has never been adequately justified. Few published experiments give sufficient information for the reader to make a fair assessment. There is a straightforward and well known realist model that fits the unadjusted data very well. In this paper, the logic of this realist model and the reasoning used by experimenters in justification of the data adjustment are discussed. It is concluded that the evidence from all Bell experiments is in urgent need of re-assessment, in the light of all the known ``loopholes''. Invalid Bell tests have frequently been used, neglecting an improved one derived by Clauser and Horne in 1974. ``Local causal'' explanations for the observations have been wrongfully neglected.

  7. Multiscale 3D manufacturing: combining thermal extrusion printing with additive and subtractive direct laser writing

    Science.gov (United States)

    Malinauskas, Mangirdas; Lukoševičius, Laurynas; MackevičiÅ«tÄ--, DovilÄ--; BalčiÅ«nas, Evaldas; RekštytÄ--, Sima; Paipulas, Domas

    2014-05-01

    A novel approach for efficient manufacturing of three-dimensional (3D) microstructured scaffolds designed for cell studies and tissue engineering applications is presented. A thermal extrusion (fused filament fabrication) 3D printer is employed as a simple and low-cost tabletop device enabling rapid materialization of CAD models out of biocompatible and biodegradable polylactic acid (PLA). Here it was used to produce cm- scale microporous (pore size varying from 100 to 400 µm) scaffolds. The fabricated objects were further laser processed in a direct laser writing (DLW) subtractive (ablation) and additive (lithography) manners. The first approach enables precise surface modification by creating micro-craters, holes and grooves thus increasing the surface roughness. An alternative way is to immerse the 3D PLA scaffold in a monomer solution and use the same DLW setup to refine its inner structure by fabricating dots, lines or a fine mesh on top as well as inside the pores of previously produced scaffolds. The DLW technique is empowered by ultrafast lasers - it allows 3D structuring with high spatial resolution in a great variety of photosensitive materials. Structure geometry on macro- to micro- scales could be finely tuned by combining these two fabrication techniques. Such artificial 3D substrates could be used for cell growth or as biocompatible-biodegradable implants. This combination of distinct material processing techniques enables rapid fabrication of diverse functional micro- featured and integrated devices. Hopefully, the proposed approach will find numerous applications in the field of ms, microfluidics, microoptics and many others.

  8. A subtraction scheme for computing QCD jet cross sections at NNLO. Integrating the iterated singly-unresolved subtraction terms

    Energy Technology Data Exchange (ETDEWEB)

    Bolzoni, Paolo [Hamburg Univ. (Germany). II. Inst. fuer Theoretische Physik; Somogyi, Gabor [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Trocsanyi, Zoltan [Debrecen Univ. (Hungary); Hungarian Academy of Sciences, Debrecen (Hungary). Inst. of Nuclear Research

    2010-11-15

    We perform the integration of all iterated singly-unresolved subtraction terms over the two-particle factorized phase space. We also sum over the unresolved parton flavours. The final result can be written as a convolution (in colour space) of the Born cross section and an insertion operator. We spell out the insertion operator in terms of 24 basic integrals that are defined explicitly. We compute the coefficients of the Laurent-expansion of these integrals in two different ways, with the method of Mellin-Barnes representations and sector decomposition. Finally, we present the Laurentexpansion of the full insertion operator for the specific examples of electron-positron annihilation into two and three jets. (orig.)

  9. Putting Essential Understanding of Addition and Subtraction into Practice: Pre-K-2

    Science.gov (United States)

    Caldwell, Janet H.; Kobett, Beth; Karp, Karen

    2014-01-01

    Do your students have the incorrect idea that addition "makes numbers bigger" and subtraction "makes numbers smaller"? Do they believe that subtraction is always "taking away"? What tasks can you offer--what questions can you ask--to determine what your students know or don't know--and move them forward in their…

  10. Putting Essential Understanding of Addition and Subtraction into Practice: Pre-K-2

    Science.gov (United States)

    Caldwell, Janet H.; Kobett, Beth; Karp, Karen

    2014-01-01

    Do your students have the incorrect idea that addition "makes numbers bigger" and subtraction "makes numbers smaller"? Do they believe that subtraction is always "taking away"? What tasks can you offer--what questions can you ask--to determine what your students know or don't know--and move them forward in their…

  11. Curricular Approaches to Connecting Subtraction to Addition and Fostering Fluency with Basic Differences in Grade 1

    Science.gov (United States)

    Baroody, Arthur J.

    2016-01-01

    Six widely used US Grade 1 curricula do not adequately address the following three developmental prerequisites identified by a proposed learning trajectory for the meaningful learning of the subtraction-as-addition strategy (e.g., for 13-8 think "what + 8 = 13?"): (a) reverse operations (adding 8 is undone by subtracting 8); (b) common…

  12. Improvement of two-way continuous-variable quantum key distribution with virtual photon subtraction

    Science.gov (United States)

    Zhao, Yijia; Zhang, Yichen; Li, Zhengyu; Yu, Song; Guo, Hong

    2017-08-01

    We propose a method to improve the performance of two-way continuous-variable quantum key distribution protocol by virtual photon subtraction. The virtual photon subtraction implemented via non-Gaussian post-selection not only enhances the entanglement of two-mode squeezed vacuum state but also has advantages in simplifying physical operation and promoting efficiency. In two-way protocol, virtual photon subtraction could be applied on two sources independently. Numerical simulations show that the optimal performance of renovated two-way protocol is obtained with photon subtraction only used by Alice. The transmission distance and tolerable excess noise are improved by using the virtual photon subtraction with appropriate parameters. Moreover, the tolerable excess noise maintains a high value with the increase in distance so that the robustness of two-way continuous-variable quantum key distribution system is significantly improved, especially at long transmission distance.

  13. All Optical Signal-Processing Techniques Utilizing Four Wave Mixing

    Directory of Open Access Journals (Sweden)

    Refat Kibria

    2015-02-01

    Full Text Available Four Wave Mixing (FWM based optical signal-processing techniques are reviewed. The use of FWM in arithmetical operation like subtraction, wavelength conversion and pattern recognition are three key parts discussed in this paper after a brief introduction on FWM and its comparison with other nonlinear mixings. Two different approaches to achieve correlation are discussed, as well as a novel technique to realize all optical subtraction of two optical signals.

  14. Averaged subtracted polarization imaging for endoscopic diagnostics of surface microstructures on translucent mucosae

    Science.gov (United States)

    Kanamori, Katsuhiro

    2016-07-01

    An endoscopic image processing technique for enhancing the appearance of microstructures on translucent mucosae is described. This technique employs two pairs of co- and cross-polarization images under two different linearly polarized lights, from which the averaged subtracted polarization image (AVSPI) is calculated. Experiments were then conducted using an acrylic phantom and excised porcine stomach tissue using a manual experimental setup with ring-type lighting, two rotating polarizers, and a color camera; better results were achieved with the proposed method than with conventional color intensity image processing. An objective evaluation method that uses texture analysis was developed and used to evaluate the enhanced microstructure images. This paper introduces two types of online, rigid-type, polarimetric endoscopic implementations using a polarized ring-shaped LED and a polarimetric camera. The first type uses a beam-splitter-type color polarimetric camera, and the second uses a single-chip monochrome polarimetric camera. Microstructures on the mucosa surface were enhanced robustly with these online endoscopes regardless of the difference in the extinction ratio of each device. These results show that polarimetric endoscopy using AVSPI is both effective and practical for hardware implementation.

  15. Digital subtraction angiography in the diagnosis of invasive hydatidiform mole. Comparison with PAG, CT and USG

    Energy Technology Data Exchange (ETDEWEB)

    Ikuma, Kenichiro; Daimon, Michiko; Muranaka, Junko; Suno, Shigeo; Takayasu, Yukio; Shibahara, Hiroaki; Sawai, Hideaki

    1987-11-01

    Pelvic angiography (PAG) by Seldinger is one of the most useful examinations for the diagnosis of trophoblastic disease and also for the assessment of the therapeutic results. This technique, however, causes some stress to the patient. Therefore, noninvasive method, such as computed tomography (CT) and ultrasonography (USG) have recently been introduced. In the 1980s, digital subtraction angiography (DSA) was developed. It is now being used increasingly in the fields of Obstetrics and Gynecology as a substitute for the conventional PAG. In this report, the results of DSA, PAG, CT and USG which were carried out before and after chemotherapy in a patient with invasive hydatidiform mole were compared. In terms of the location, size and shape of the lesion, the CT findings were almost the same as those of USG. In terms of the angiographic findings in the affected area, intravenous DSA (IVDSA) was a sufficiently substitutional examination for conventional PAG. With IVDSA, arterial images can be obtained following the intravenous injection of a contrast medium. Therefore, this technique is excellent in terms of simplicity and safety. From now on, DSA will be utilized instead of PAG as an effective diagnostic method for trophoblastic disease and for follow-up such cases.

  16. [Digital subtraction angiography with carbon dioxide in severe arterial ischemia and allergy to iodinated compounds].

    Science.gov (United States)

    Calvo Cascallo, J; Mundi Salvadó, N; Cardona Fontanet, M

    1993-01-01

    When in some selected patients, a direct arterial surgery (DAS) procedure or an endoluminal surgery (ES) are required for a chronic arterial ischemia (III or IV degrees), and an arteriography with contrast is absolutely contraindicated (because of severe renal failure without hemodialysis program or a severe congestive heart failure or a hyperthyroidism or a seriously demonstrated hypersensibility against the contrast agents); an angiography by digital subtraction with carbon dioxide (DIVAS-CO2) is indicated. This technique provides good quality images with minimal risks for the patient and an adequate study for ulterior treatment. We report a case of a 67-years-old woman, with diabetes-II, ischemic cardiopathy, arterial hypertension and a demonstrated hypersensibility against the iodide compounds. The patient was admitted because of a chronic ischemia (IV degree) with ischemic ulcerations on some fingers from the left foot. High doses of analgesic drugs were needed. Because the hypersensibility against the iodide compounds, an angiography with CO2 was carried out. The good quality images provided by this technique showed the factibility of a revascularization.

  17. Femoral head vascularisation in Legg-Calve-Perthes disease: comparison of dynamic gadolinium-enhanced subtraction MRI with bone scintigraphy

    Energy Technology Data Exchange (ETDEWEB)

    Lamer, Sylvie; Dorgeret, Sophie; Brillet, Pierre-Yves; Hassan, Max; Sebag, Guy H. [Department of Paediatric Radiology, Hopital Robert Debre, 48 boulevard Serurier, 75935 Paris Cedex (France); Lariboisiere-Saint-Louis University, Paris (France); Khairouni, Abdeslam; Mazda, Keyvan; Bacheville, Eric; Pennecot, Georges F. [Department of Paediatric Orthopaedics, Hopital Robert Debre, Paris (France); Bloch, Juliette [Department of Biostatistics, Hopital Robert Debre, Paris (France)

    2002-08-01

    Heading AbstractBackground. It has been reported that MRI using a dynamic gadolinium-enhanced subtraction technique can allow the early identification of ischaemia and the pattern of revascularisation in Legg-Calve-Perthes (LCP) disease with increased spatial and contrast resolution. Therefore, dynamic gadolinium-enhanced subtraction (DGS) MRI may be a possible non-ionising substitute for bone scintigraphy.Objective. The purpose of this prospective study was to compare DGS MRI and bone scintigraphy in the assessment of femoral head perfusion in LCP disease.Materials and methods. Twenty-six DGS MR images and bone scintigraphies of 25 hips in 23 children were obtained at different stages of LCP disease; three stage I, 12 stage II, six stage III and five stage IV (Waldenstroem classification). The extent of necrosis, epiphyseal revascularisation pathways (lateral pillar, medial pillar, and/or transphyseal perfusion) and metaphyseal changes were analysed.Results. Total agreement between both techniques was noted in the depiction of epiphyseal necrosis (kappa=1), and metaphyseal abnormalities (kappa=0.9). DGS MRI demonstrated better revascularisation in the lateral (kappa=0.62) and medial pillars (kappa=0.52). The presence of basal transphyseal reperfusion was more conspicuous with MRI.Conclusions. DGS MRI allows early detection of epiphyseal ischaemia and accurate analysis of the different revascularisation patterns. These changes are directly related to the prognosis of LCP disease and can aid therapeutic decision making. (orig.)

  18. Dual energy subtraction method for breast calcification imaging

    Science.gov (United States)

    Koukou, Vaia; Martini, Niki; Fountos, George; Michail, Christos; Sotiropoulou, Panagiota; Bakas, Athanasios; Kalyvas, Nektarios; Kandarakis, Ioannis; Speller, Robert; Nikiforidis, George

    2017-03-01

    The aim of this work was to present an experimental dual energy (DE) method for the visualization of microcalcifications (μCs). A modified radiographic X-ray tube combined with a high resolution complementary metal-oxide-semiconductor (CMOS) active pixel sensor (APS) X-ray detector was used. A 40/70 kV spectral combination was filtered with 100 μm cadmium (Cd) and 1000 μm copper (Cu) for the low/high-energy combination. Homogenous and inhomogeneous breast phantoms and two calcification phantoms were constructed with various calcification thicknesses, ranging from 16 to 152 μm . Contrast-to-noise ratio (CNR) was calculated from the DE subtracted images for various entrance surface doses. A calcification thickness of 152 μm was visible, with mean glandular doses (MGD) in the acceptable levels (below 3 mGy). Additional post-processing on the DE images of the inhomogeneous breast phantom resulted in a minimum visible calcification thickness of 93 μm (MGD=1.62 mGy). The proposed DE method could potentially improve calcification visibility in DE breast calcification imaging.

  19. Skycorr: A general tool for spectroscopic sky subtraction

    CERN Document Server

    Noll, S; Kimeswenger, S; Barden, M; Jones, A M; Modigliani, A; Szyszka, C; Taylor, J

    2014-01-01

    Airglow emission lines, which dominate the optical-to-near-IR sky radiation, show strong, line-dependent variability on various time scales. Therefore, the subtraction of the sky background in the affected wavelength regime becomes a problem if plain sky spectra have to be taken at a different time as the astronomical data. A solution of this issue is the physically motivated scaling of the airglow lines in the plain sky data to fit the sky lines in the object spectrum. We have developed a corresponding instrument-independent approach based on one-dimensional spectra. Our code skycorr separates sky lines and sky/object continuum by an iterative approach involving a line finder and airglow line data. The sky lines are grouped according to their expected variability. The line groups in the sky data are then scaled to fit the sky in the science data. Required pixel-specific weights for overlapping groups are taken from a comprehensive airglow model. Deviations in the wavelength calibration are corrected by fitti...

  20. Microwave detection of breast tumors: comparison of skin subtraction algorithms

    Science.gov (United States)

    Fear, Elise C.; Stuchly, Maria A.

    2000-07-01

    Early detection of breast cancer is an important part of effective treatment. Microwave detection of breast cancer is of interest due to the contrast in dielectric properties of normal and malignant breast tissues. We are investigating a confocal microwave imaging system that adapts ideas from ground penetrating radar to breast cancer detection. In the proposed system, the patient lies prone with the breast extending through a hole in the examining table and encircled by an array of antennas. The breast is illuminated sequentially by each antenna with an ultrawideband signal, and the returns are recorded at the same antenna. Because the antennas are offset from the breast, the dominant component of the recorded returns is the reflection from the thin layer of breast skin. Two methods of reducing this reflection are compared, namely approximation of the signal with two time shifted, scaled and summed returns from a cylinder of skin, and subtraction of the mean of the set of aligned returns. Both approaches provide effective decrease of the skin signal, allowing for tumor detection.

  1. Subtractive fuzzy classifier based driver distraction levels classification using EEG.

    Science.gov (United States)

    Wali, Mousa Kadhim; Murugappan, Murugappan; Ahmad, Badlishah

    2013-09-01

    [Purpose] In earlier studies of driver distraction, researchers classified distraction into two levels (not distracted, and distracted). This study classified four levels of distraction (neutral, low, medium, high). [Subjects and Methods] Fifty Asian subjects (n=50, 43 males, 7 females), age range 20-35 years, who were free from any disease, participated in this study. Wireless EEG signals were recorded by 14 electrodes during four types of distraction stimuli (Global Position Systems (GPS), music player, short message service (SMS), and mental tasks). We derived the amplitude spectrum of three different frequency bands, theta, alpha, and beta of EEG. Then, based on fusion of discrete wavelet packet transforms and fast fourier transform yield, we extracted two features (power spectral density, spectral centroid frequency) of different wavelets (db4, db8, sym8, and coif5). Mean ± SD was calculated and analysis of variance (ANOVA) was performed. A fuzzy inference system classifier was applied to different wavelets using the two extracted features. [Results] The results indicate that the two features of sym8 posses highly significant discrimination across the four levels of distraction, and the best average accuracy achieved by the subtractive fuzzy classifier was 79.21% using the power spectral density feature extracted using the sym8 wavelet. [Conclusion] These findings suggest that EEG signals can be used to monitor distraction level intensity in order to alert drivers to high levels of distraction.

  2. Use of digital subtraction angiography for assessment of digital replantatlon

    Institute of Scientific and Technical Information of China (English)

    Liu-hong WANG; Guang-qiang ZHANG

    2012-01-01

    Objective:To assess the blood flow of the proper digital artery using digital subtraction angiography (DSA) in the early stage after replantation.Methods:From January 2006 to October 2010,27 anastomosed arteries in 27 replanted digits were included in the study.The patients included nine males and four females.The patients received DSA at 48 to 96 h after digital replantation.Based on DSA image,the blood flow was classified into normal,slow-running,and flow-stopping types.The patients with normal digital blood flow were given continuous routine treatments; the patients with slow-running flow were given the conservative treatments,such as release of the tight dressings,removal of stitches,keeping warm,the use of massage,and the use of anticoagulants and anti-inflammatory drugs; the patients with flow-stopping received immediate surgical re-exploration.Results:In this series,23 digits in 11 patients showed a normal blood flow,and these digits all survived.In one of 13 patients,two digits which displayed slow-running flow also survived after conservative treatments.In two of 13 patients,two digits showed flow stopping,with one surviving and one failing after re-exploration and arterial revision.Conclusions:The DSA can be used to assess the blood flow of the proper digital artery in the early stage after replantation.It provides essential information for salvaging the replanted finger.

  3. Data series subtraction with unknown and unmodeled background noise

    CERN Document Server

    Vitale, Stefano; Dolesi, Rita; Ferroni, Valerio; Hueller, Mauro; Vetrugno, Daniele; Weber, William Joseph; Audley, Heather; Danzmann, Karsten; Diepholz, Ingo; Hewitson, Martin; Korsakova, Natalia; Ferraioli, Luigi; Gibert, Ferran; Karnesis, Nikolaos; Nofrarias, Miquel; Inchauspe, Henri; Plagnol, Eric; Jennrich, Oliver; McNamara, Paul W; Armano, Michele; Thorpe, James Ira; Wass, Peter

    2014-01-01

    LISA Pathfinder (LPF), ESA's precursor mission to a gravitational wave observatory, will measure the degree to which two test-masses can be put into free-fall, aiming to demonstrate a residual relative acceleration with a power spectral density (PSD) below 30 fm/s$^2$/Hz$^{1/2}$ around 1 mHz. In LPF data analysis, the measured relative acceleration data series must be fit to other various measured time series data. This fitting is required in different experiments, from system identification of the test mass and satellite dynamics to the subtraction of noise contributions from measured known disturbances. In all cases, the background noise, described by the PSD of the fit residuals, is expected to be coloured, requiring that we perform such fits in the frequency domain. This PSD is unknown {\\it a priori}, and a high accuracy estimate of this residual acceleration noise is an essential output of our analysis. In this paper we present a fitting method based on Bayesian parameter estimation with an unknown frequ...

  4. Generalized Subtraction Schemes for the Difference Formulation in Radiation Transport

    Energy Technology Data Exchange (ETDEWEB)

    Luu, T; Brooks, E; Szoke, A

    2008-07-25

    In the difference formulation for the transport of thermally emitted photons, the photon intensity is defined relative to a reference field, the black body at the local material temperature. This choice of reference field removes the cancellation between thermal emission and absorption that is responsible for noise in the Monte Carlo solution of thick systems, but introduces time and space derivative source terms that can not be determined until the end of the time step. It can also lead to noise induced crashes under certain conditions where the real physical photon intensity differs strongly from a black body at the local material temperature. In this report, we consider a difference formulation relative to the material temperature at the beginning of the time step, and in the situations where the radiation intensity more closely follows a temperature other than the local material temperature, that temperature. The result is a method where iterative solution of the material energy equation is efficient and noise induced crashes are avoided. To support our contention that the resulting generalized subtraction scheme is robust, and therefore suitable for practical use, we perform a stability analysis in the thick limit where instabilities usually occur.

  5. Diagnosis of carotid body tumor by digital subtraction angiography

    Institute of Scientific and Technical Information of China (English)

    戚跃勇; 邹利光; 孙清荣; 徐健; 周政; 谭颖徽

    2004-01-01

    Objective: To make a further understanding of the features of the carotid body tumor (CBT) by digital subtraction angiography (DSA) so as to explore the clinical value of DSA diagnosis and interventional therapy for CBT. Methods: DSA data from 12 cases of CBT were analyzed retrospectively. A consensus interpretation of the DSA appearances in all of the patients was reached after dynamic observation by 2 experienced radiologists in a double-blind manner. Results: Definite diagnosis in all cases could be made by DSA. The DSA features of the CBT included bigger bifurcation angles of the internal and external carotid arteries, displacement of internal and external carotid arteries, CBT supplied by external carotid arteries in most cases and the significant increase of tumor blood vessels in bifurcation. Invasion of internal or external carotid arteries was found in 6 cases. Smaller stained area of the tumor and significantly reduced intraoperative bleeding were found after embolization of the supplying arteria in 2 cases. Conclusion: DSA is the effective method for the diagnosis and preoperative assessment of CBT. Preoperative embolization of CBT may contribute to the reduced intraoperative bleeding.

  6. Subtraction CT angiography for evaluation of intracranial aneurysms: comparison with conventional CT angiography

    Energy Technology Data Exchange (ETDEWEB)

    Li, Qi; Li, Kewei; Xie, Peng [The First Affiliated Hospital, Chongqing Medical University, Department of Neurology, Chongqing (China); Lv, Fajin; Li, Yongmei; Luo, Tianyou [The First Affiliated Hospital, Chongqing Medical University, Department of Radiology, Chongqing (China)

    2009-09-15

    The purpose of our study was to compare the diagnostic performance of subtraction computed tomography angiography (CTA) with conventional nonsubtracted CTA and digital subtraction angiography (DSA) for the detection of intracranial aneurysms. A total of 76 patients underwent both subtraction CTA and conventional CTA for the detection and therapy planning of suspected intracranial aneurysms. Subtraction and conventional CTA images were independently assessed by two readers in a blinded manner. The possibility of endovascular treatment or surgical clipping was also assessed based on information provided by CT angiograms alone. In 64 patients, 75 aneurysms were present on DSA. On a per-aneurysm basis, the sensitivity of subtraction CTA was 98.6% for reader 1, and 100% for reader 2. However, sensitivity of conventional CTA was 94.6% for reader 1, and 93.3% for reader 2. Therapeutic decisions could be made regarding 63 patients based on information provided by subtraction CTA images. However, conventional CTA provided sufficient information to make this decision for 55 patients. Conventional CTA has limited sensitivity in detecting very small aneurysms as well as aneurysms adjacent to bone. Subtraction CTA performed on a 64-row multidetector CT is an accurate and promising diagnostic tool that seems to be equivalent to 2D DSA for the detection and pretreatment planning of intracranial aneurysms. (orig.)

  7. Construction and selection of subtracted cDNA library of mouse hepatocarcinoma cell lines with different lymphatic metastasis potential

    Institute of Scientific and Technical Information of China (English)

    Li Hou; Jan-Wu Tang; Xiao-Nan Cui; Bo Wang; Bo Song; Lei Sun

    2004-01-01

    AIM: In order to elucidate the molecular mechanism of lymphatic metastasis of hepatocarcinoma, we detected the difference of gene expression between mouse hepatocarcinoma cell lines Hca-F and Hca-P with different lymphatic metastasis potential.METHODS: cDNA of Hca-F cells was used as a tester and cDNA of Hca-P cells was used as a driver. cDNAs highly expressed in Hca-F cells were isolated by the suppression subtractive hybridization (SSH) method. The isolated cDNA was cloned into T/A cloning vector. The ligation products were transformed into DH5 α competent cells. Individual clones were randomly selected and used for PCR amplification.Vector DNA from positive clones was isolated for sequencing.RESULTS: There were 800 positive clones in amplified subtracted cDNA library. Random analysis of 160 clones with PCR showed that 95% of the clones contained 100-700 bp inserts. Analysis of 20 sequenced cDNA clones randomly picked from the SSH library revealed 4 known genes (mouse heat shock protein 84 ku, DNA helicase, ribosomal protein S13 ,ethanol induced 6 gene) and 3 expressed sequence tags (ESTs). Four cDNAs showed no homology and presumably represent novel genes.CONCLUSION: A subtracted cDNA library of differentially expressed genes in mouse heptocarcinoma cell lines with different lymphatic metastasis potential was successfully constructed with SSH and T/A cloning techniques. The library is efficient and lays a solid foundation for searching new lymphatic metastasis related genes. The expression of mouse heat shock protein gene, DNA helicase and other 4 novel gene may be different between mouse heptocarcinoma cell lines with different lymphatic metastasis potential.

  8. Comparison of conventional panoramic radiography and panoramic digital subtraction radiography in detection of simulated lesions of mandibular condyle

    Directory of Open Access Journals (Sweden)

    Panjnoush M.

    2008-12-01

    Full Text Available "n  "nBackground and Aim: Digital subtraction Radiography (DSR is a method of accurate assessing condylar head changes. several studies have been carried out in applying DSR in dentistry, however there is a few number of studies in efficacy of DSR method in assesment of condylar head changes, The aim of this study was to compare panoramic radiography and DSR detecting simulated lesions of the mandibular condyl. "nMaterials and Methods: this was a process reaserch study, in which two dry human skulls with no obvious temporomandibular joint pathology were used. Osteophytic lesions were simulated using three sizes of bone chips that were placed on the medial portion of anterior and superolateral aspects of the condyle. Osteolytic lesions were simulated making 1 and 2 mm holes using round burr in the central portion of anterior aspect and Lateral pole of the condyle. Panoramic radiographs were prepared with and without the lesions in place. These paired radiographs were digitized and digital- subtraction images of the original panoramic images were obtained. Eight observers evaluated 155 images of each modality for the presence or absence and the type of simulated lesions of the mandibular condyle. Sensitivity, specificity, reliability and measure of agreement were analyzed using kappa test and crossed tables and qualitative variables were assess by chi-square and fisher's Exact test. "nResults: Specificity of panoramic and DSR methods were 15.4% and 66.7% respectively. Sensitivity of panoramic and DSR methods were 61.1% and 80.6% for osteophytic lesions and 37.5% and 83.3% for Osteolytic lesions. The percentage of correct decisions made in DSR method was significantly more than conventional panoramic method (82.6% vs 41.9% (p<0.0001. "nConclusion: Based on the results of this study digital subtraction technique was significantly more accurate than the panoramic radiographs in detection of simulated lesions of the mandibular condyle.

  9. Redefining the Whole: Common Errors in Elementary Preservice Teachers' Self-Authored Word Problems for Fraction Subtraction

    Science.gov (United States)

    Dixon, Juli K.; Andreasen, Janet B.; Avila, Cheryl L.; Bawatneh, Zyad; Deichert, Deana L.; Howse, Tashana D.; Turner, Mercedes Sotillo

    2014-01-01

    A goal of this study was to examine elementary preservice teachers' (PSTs) ability to contextualize and decontextualize fraction subtraction by asking them to write word problems to represent fraction subtraction expressions and to choose prewritten word problems to support given fraction subtraction expressions. Three themes emerged from the…

  10. Three-dimensional digital subtraction angiography vs two-dimensional digital subtraction angiography for detection of ruptured intracranial aneurysms: A study of 86 aneurysms

    Directory of Open Access Journals (Sweden)

    Kawashima Masatou

    2005-01-01

    Full Text Available Aims : Three-dimensional reconstruction of intracranial vessels is of interest for evaluation of aneurysms. This study determined diagnostic difference of three-dimensional digital subtraction angiography (3D-DSA, volume-rendering image versus 2D-DSA for evaluating ruptured intracranial aneurysms, particularly focusing on the size of aneurysms as depicted in both images. Settings and Design : Sixty-nine patients underwent 3D-DSA and 2D-DSA. The relative size of an aneurysm, which is the ratio of the maximal diameter of an aneurysm to the diameter of a major vessel, was compared between imaging techniques. In addition, relative sizes of smaller aneurysms (10 mm. Statistical analysis used : For comparison of aneurysm size and location of aneurysm, statistical analysis was performed with the Yates chi square test; statistical significance was set with a P value of less than 0.05. Results: Sixty-three (73.3% of the 86 total aneurysms were bigger when measured with 3D-DSA versus 2D-DSA. When measured with 3D-DSA, 28 (84.8% of the 33 smaller aneurysms were bigger, and 50% of the larger aneurysms were bigger versus measurements of 2D-DSA images ( P P Conclusions : 3D-DSA, especially volume-rendering images, tends to depict ruptured intracranial aneurysms bigger than 2D-DSA. This is particularly true with cerebral aneurysms that are <5 mm in size and are located in the anterior circulation, especially ICA and ACA territories.

  11. 化脓性链球菌高毒力株特异基因文库的构建和分析%Construction and analysis of virulence genes subtracted library of streptococcus pyogenes by suppression subtractive hybridization

    Institute of Scientific and Technical Information of China (English)

    田福亮; 吴剑锋; 夏永祥

    2012-01-01

    Objective To construct the virulence genes subtracted library of streptococcus pyogenes and to lay the foundations for screening the virulent genes. Methods Suppression subtractive hybridization was adopted to isolate the fragments of virulence genes in streptococcus pyogenes. Then these fragments were directly inserted into T/A cloning vector to set up subtractive library and amplication of the library was carried out with transformation of E. Coil TOP10. Dot blot was used to screen the subtracted library,the differentially expressed cDNA fragments were sequenced and analyzed in Genebank with Blast search. Results A smear ranged from 100 ~ 2000 bp was observed. The ligation efficiency of tester DNA with adaptor was at least higher than 50 percent. The difference between subtractive group and unsbtractive group was apparently significant. Partial positive clones in the library were randomly selected and successfully sequenced. 5/12 sequence showed no homology and presumably represent unknown genes, 7/12 had a high similarity to the known genes. Conclusion The virulence genes subtracted library of streptococcus pyogenes is constructed successfully with SSH and T/A cloning techniques. The library is efficient and lays solid foundation for screening and cloning new and specific virulence genes of streptococcus pyogenes.%目的 构建化脓性链球菌高毒力株特异基因文库,克隆和筛选化脓性链球菌高毒力株特异表达基因.方法 采用抑制消减杂交技术(SSH),以从患者体内所分离链球菌为毒力菌株,分离特异表达基因,将其与T载体进行T/A连接构建文库,将连接产物转化感受态大肠杆菌TOP10进行文库扩增后,转化菌液涂布于LB固体平板,构建化脓性链球菌毒力株特异基因消减文库,用斑点杂交初步筛选消减文库后,将获得的阳性克隆进行测序和同源性分析.结果 酶切产物为100~2 000 bp,连接效率大于50%,消减组与非消减组差异明显,成功构

  12. Exponential Renormalization II: Bogoliubov's R-operation and momentum subtraction schemes

    CERN Document Server

    Ebrahimi-Fard, Kurusch

    2011-01-01

    We develop further the recently introduced exponential method for renormalisation in perturbative quantum field theory. It turns out that exponential renormalisation provides a meaningful recursive method in the context of renormalisation using momentum subtraction schemes. We explore in detail its link to Bogoliubov's R-operation. Our results shed new light on classical ideas, such as the role of oversubtractions in the BPHZ method. They also suggest that the ambiguities of the renormalisation process carry, besides a physical structure (encoded, e.g. in the RG equations and the choice of subtraction points in momentum subtraction schemes), an interesting, though purely algebraic structure.

  13. Exponential renormalisation. II. Bogoliubov's R-operation and momentum subtraction schemes

    Energy Technology Data Exchange (ETDEWEB)

    Ebrahimi-Fard, Kurusch [Instituto de Ciencias Matematicas, C/ Nicolas Cabrera, no. 13-15, 28049 Madrid (Spain); Patras, Frederic [Laboratoire J.-A. Dieudonne UMR 6621, CNRS, Parc Valrose, 06108 Nice Cedex 02 (France)

    2012-08-15

    This article aims at advancing the recently introduced exponential method for renormalisation in perturbative quantum field theory. It is shown that this new procedure provides a meaningful recursive scheme in the context of the algebraic and group theoretical approach to renormalisation. In particular, we describe in detail a Hopf algebraic formulation of Bogoliubov's classical R-operation and counterterm recursion in the context of momentum subtraction schemes. This approach allows us to propose an algebraic classification of different subtraction schemes. Our results shed light on the peculiar algebraic role played by the degrees of Taylor jet expansions, especially the notion of minimal subtraction and oversubtractions.

  14. Demonstration Of Synthetic Exo-earth Detection In The Lab With Speckle Subtraction Techniques

    Science.gov (United States)

    Belikov, Ruslan; Give'on, A.; Savransky, D.; Pueyo, L.; Kern, B.; Kasdin, J.

    2007-12-01

    The problem of detecting and imaging earth-like exoplanets is hampered by the fact that wavefront error in the optics of a space telescope creates a speckle pattern that can swamp the exoplanet. The standard approach for dealing with speckles is to suppress them below the planet level by a deformable mirror using a wavefront control algorithm. However, such wavefront control may take a long time to achieve speckle suppression of 1010, the nominal contrast necessary for exo-earths, especially if the target star is dim. Furthermore, a very precise deformable mirror and electronics are required. In this paper, we present and demonstrate in the lab a method to detect planet light from amidst a brighter speckle pattern (as long as that pattern is stable), thus relaxing the requirement of 1010 speckle suppression. Furthermore, our detection is simultaneous with wavefront control and uses all the images taken in the course of wavefront control, saving valuable mission time. The method consists of (a) using the wavefront control estimate of the coherent speckle field to separate the speckles from the incoherent planet light, and (b) using a matched filter to reduce noise. No motion or rotation of the telescope is required for this method. The experiment was conducted on the High Contrast Imaging Testbed at the Jet Propulsion Lab using the Shaped Pupil coronagraph under 10% optical bandwidth. This work was funded in part by JPL contract 1254357 and the Michelson Science Center, and carried out in part at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration.

  15. Manifestations of hepatic cavernous hemangioma in carbon dioxidedigital subtraction angiography

    Institute of Scientific and Technical Information of China (English)

    LU Wei; LI Yan-ha0; HE Xiao-feng; CHEN Yong; ZENG Qing-le

    2002-01-01

    Objective: To describe the characteristic appearance of cavernous hemangioma of the liver (CHL)presented in carbon dioxide digital subtraction angiography (CO2-DSA) and to evaluate the significance of CO2-DSA in the diagnosis of CHL. Methods: Both CO2-DSA and iodinated contrast DSA (IC-DSA) were performed in all 16 patients with CHL, and the angiographic manifestations in the same patients were compared. The image quality was rated by three experienced angiographers, and the complications were also assessed. Results; There was good correlation between angiographers on image quality (R=0. 73). Diagnostic images were obtained with both CO2-DSA and IC-DSA in all CHL patients. No difference was noted between IC-DSA and CO2-DSA in visualizing the proper hepatic arteries and its branches (P>0. 05). CO2-DSA produced better images that clearly described the tumor size, shape and margination than those by IC-DSA (P<0. 05), but both demonstrated characteristic appearances of early opacification and persistent contrast enhancement of the tumors. The portal vein branches near the tumors were constantly demonstrated by CO2-DSA in 15 cases (15/16) but only in 2 cases (2/16) by IC-DSA. Conclusion: CO2-DSA is sensitive in CHL diagnosis, and in patients with contraindications to IC or with unsatisfactory imaging results by IC-DSA,CO2-DSA is a good alternative. As show in most cases by CO2-DSA, the portal veins might act as the main drainage vein of CHLs.

  16. Digital subtraction angiography of the cerebral vessels by intraarterial injection

    Energy Technology Data Exchange (ETDEWEB)

    Nagata, Izumi; Kikuchi, Haruhiko; Karasawa, Jun; Mitsugi, Toru; Naruo, Yoshito; Takamiya, Makoto (National Cardiovascular Center, Suita, Osaka (Japan))

    1984-10-01

    Three hundred and fifty-seven digital subtraction angiography (DSA) were performed in 184 neurosurgical patients by intraarterial injection. Examinations consisted of 192 carotid angiography, 110 vertebral angiography, 23 aortography, 11 spinal angiography and 21 other angiography. In all examinations, visualization of the vessels was excellent and the complications were never experienced. High contrast sensitivity of DSA resulted in better visualization of tumor stains, phlebogram, and arteries in cerebral arteriovenous malformations with large shunt blood flow than conventional angiography. Selective catheterization into each cerebral arteries was not necessarily demanded for good opacification of the vessels because of high sensitivity. High contrast sensitivity also permitted low concentration of contrast material, small dose of contrast material, and slow injection rate. Low concentration of contrast material reduced pain and heat during injection especially in the external carotid and vertebral angiography. Using slow injection, recoiling of catheter into the aorta was reduced, so that injection from the innominate and subclavian arteries for visualization of origin of the cerebral arteries were always successful. Full study of cerebral arteries by Seldinger's method, if necessary, was easily achieved using DSA even in patient with high age or with severe atherosclerosis. Bolus injection of small dose of contrast material as well as serial imaging was helpful in evaluating hemodynamics in the lesion. Real time display of DSA reduced the time required for angiography and was very convenient for artificial embolization. Besides these advantages, DSA became comparable to conventional angiography in spacial resolution by use of intraarterial injection and could be a preoperative genuine examination as well as a screening method.

  17. A comparison between magnetic resonance angiography at 3 teslas (time-of-flight and contrast-enhanced and flat-panel digital subtraction angiography in the assessment of embolized brain aneurysms

    Directory of Open Access Journals (Sweden)

    Guilherme S. Nakiri

    2011-01-01

    Full Text Available PURPOSE: To compare the time-of-flight and contrast-enhanced- magnetic resonance angiography techniques in a 3 Tesla magnetic resonance unit with digital subtraction angiography with the latest flat-panel technology and 3D reconstruction in the evaluation of embolized cerebral aneurysms. INTRODUCTION: Many embolized aneurysms are subject to a recurrence of intra-aneurismal filling. Traditionally, imaging surveillance of coiled aneurysms has consisted of repeated digital subtraction angiography. However, this method has a small but significant risk of neurological complications, and many authors have advocated the use of noninvasive imaging methods for the surveillance of embolized aneurysms. METHODS: Forty-three aneurysms in 30 patients were studied consecutively between November 2009 and May 2010. Two interventional neuroradiologists rated the time-of-flight-magnetic resonance angiography, the contrast-enhanced-magnetic resonance angiography, and finally the digital subtraction angiography, first independently and then in consensus. The status of aneurysm occlusion was assessed according to the Raymond scale, which indicates the level of recanalization according to degrees: Class 1: excluded aneurysm; Class 2: persistence of a residual neck; Class 3: persistence of a residual aneurysm. The agreement among the analyses was assessed by applying the Kappa statistic. RESULTS: Inter-observer agreement was excellent for both methods (K = 0.93; 95 % CI: 0.84-1. Inter-technical agreement was almost perfect between time-of-flight-magnetic resonance angiography and digital subtraction angiography (K = 0.98; 95 % CI: 0.93-1 and between time-of-flight-magnetic resonance angiography and contrast-enhanced-magnetic resonance angiography (K = 0.98; 95% CI: 0.93-1. Disagreement occurred in only one case (2.3%, which was classified as Class I by time-of-flight-magnetic resonance angiography and Class II by digital subtraction angiography. The agreement between

  18. Data acquisition and analysis for the energy-subtraction Compton scatter camera for medical imaging

    Science.gov (United States)

    Khamzin, Murat Kamilevich

    In response to the shortcomings of the Anger camera currently being used in conventional SPECT, particularly the trade-off between sensitivity and spatial resolution, a novel energy-subtraction Compton scatter camera, or the ESCSC, has been proposed. A successful clinical implementation of the ESCSC could revolutionize the field of SPECT. Features of this camera include utilization of silicon and CdZnTe detectors in primary and secondary detector systems, list-mode time stamping data acquisition, modular architecture, and post-acquisition data analysis. Previous ESCSC studies were based on Monte Carlo modeling. The objective of this work is to test the theoretical framework developed in previous studies by developing the data acquisition and analysis techniques necessary to implement the ESCSC. The camera model working in list-mode with time stamping was successfully built and tested thus confirming potential of the ESCSC that was predicted in previous simulation studies. The obtained data were processed during the post-acquisition data analysis based on preferred event selection criteria. Along with the construction of a camera model and proving the approach, the post-acquisition data analysis was further extended to include preferred event weighting based on the likelihood of a preferred event to be a true preferred event. While formulated to show ESCSC capabilities, the results of this study are important for any Compton scatter camera implementation as well as for coincidence data acquisition systems in general.

  19. VLSI implementation of a template subtraction algorithm for real-time stimulus artifact rejection.

    Science.gov (United States)

    Limnuson, Kanokwan; Lu, Hui; Chiel, Hillel J; Mohseni, Pedram

    2010-01-01

    In this paper, we present very-large-scale integrated (VLSI) implementation of a template subtraction algorithm for stimulus artifact rejection (SAR) in real time with applicability to closed-loop neuroprostheses. The SAR algorithm is based upon an infinite impulse response (IIR) temporal filtering technique, which can be efficiently implemented in VLSI with reduced power consumption and silicon area. We demonstrate that initialization of the memory within the system architecture using the first recorded stimulus artifact significantly decreases system response time as compared to the case without memory initialization. Two sets of pre-recorded neural data from an Aplysia californica are used to simulate the functionality of the proposed VLSI architecture in AMS 0.35 microm complementary metal-oxide-semiconductor (CMOS) technology. Depending upon the reproducibility in the shape of stimulus artifacts in vivo, the system eliminates virtually all artifacts in real time and recovers the extracellular neural activity with microW-level power consumption from 1.5 V.

  20. Identification of calcium stress induced genes in amaranth leaves through suppression subtractive hybridization.

    Science.gov (United States)

    Aguilar-Hernández, Hugo S; Santos, Leticia; León-Galván, Fabiola; Barrera-Pacheco, Alberto; Espitia-Rangel, Eduardo; De León-Rodríguez, Antonio; Guevara-González, Ramón G; Barba de la Rosa, Ana P

    2011-11-15

    Calcium (Ca(2+)) is a critical ion for the growth and development of plants and plays an important role in signal transduction pathways in response to biotic and abiotic stresses. We investigated the Ca(2+) stress responsive-genes in amaranth leaves by using the suppression subtractive hybridization technique. Screening of the libraries generated 420 up-regulated transcripts and 199 down-regulated transcripts. The differentially expressed transcripts were associated with general stress response, transcription factors, gene regulation, signal transduction, and some other with unknown function. Selected genes were used to study their differential regulation by sqRT-PCR. Among the up-regulated transcripts, a fragment containing the motif of C3HC4-type RING-Zinc family was further characterized. The ORF of amaranth zinc finger protein (AhZnf) has a closer relationship with its ortholog from Ricinus communis while is distantly related to the Arabidopsis thaliana C3HC4-type ortholog. We have identified a novel putative zinc finger protein along with other novel proteins such as the wall associated kinase, phosphoinositide binding protein, and rhomboid protease involved in response to Ca(2+) stress in amaranth leaves.

  1. A digital subtraction radiography based tool for periodontal bone resorption analysis

    Energy Technology Data Exchange (ETDEWEB)

    Schiabel, Homero; Rodrigues, Eveline B., E-mail: homero@sc.usp.br [University of Sao Paulo (EESC/USP), Sao Carlos, SP (Brazil). Dept. of Electrical Engineering; Rubira-Bullen, Izabel R.F. [University of Sao Paulo (USP), Bauru, SP (Brazil). Bauru Dentistry School

    2011-07-01

    The aim of this paper was to describe an aided diagnosis scheme for periodontal bone resorption so that the dentist can make an early diagnosis of the periodontal disease and establish the best treatment plan to increase the success of healing. Three ways of displaying the results are provided: qualitative, simple quantitative and colored-percentage quantitative views. A total of 72 pairs of in vitro radiographic images were used. The main procedure registers the images perspective projection aimed to align them in rotation and translation, and is followed by the application of a contrast correction technique. The results from the subtraction were evaluated firstly by the comparison between the actual and the digital sizes corresponding to the holes made by drills in phantoms. The mean error was 4.2%. The method was also applied to actual tooth radiographic images and could detect clearly the effect of treatment of periodontal diseases. It is dependent on the reproducibility of the process of radiographs acquisition and digitization, but the calculated mean error allows to conclude its better efficacy compared to usual procedures in this field. (author)

  2. Experience with intravenous digital subtraction angiography following shunting in 4 cases of congenital heart diseases

    Energy Technology Data Exchange (ETDEWEB)

    Higashidate, Masafumi; Konno, Susumu; Sumitomo, Naokata; Ito, Sango; Kobayashi, Hiroshi

    1985-01-01

    Intravenous digital subtraction angiography (IV-DSA) was performed in two patients with Fallot's tetralogy who underwent Blalock-Taussing operation, a patient with coarctation of the aortic arch who underwent extra-anastomic bypass between the ascending aorta and the descending aorta, and a patient with stenosis of the tricuspid valve who underwent Fontan type operation (anastomosis between the right atrium and the pulmonary artery). The conventional cardiac angiography was also performed for the comparison with IV-DSA in all patients. IV-DSA revealed the thickness of the subclavian artery anastomosed by Blaloch-Taussing operation, but failed to determine the accurate thickness of the pulmonary artery required for PA-index for radical surgery in cases of Fallot's tetralogy. Bypass from the ascending aorta to the descending aorta was well visualized by IV-DSA because the heart did not overlap on the image. In cases of Fontan type operation, IV-DSA permitted the visualization of blood flow from the right atrium to the pulmonary artery and the shape of the pulmonary artery. It is concluded that IV-DSA is a less invasive, simple technique to evaluate patients' condition following shunting for congenital heart diseases, as compared to the conventional method. (Namekawa, K.).

  3. Screening Mouse Genes Related to Blastocyst Implantation by Using PCR Subtraction

    Institute of Scientific and Technical Information of China (English)

    Zhe-ping HUANG; Jian WANG; Wei-xiong SHEN; Ping HUANG; Jia-ke TSO; Qing-xiang SHEN

    2002-01-01

    Objective To identify genes that may be related to embryo implantation Materials & Methods The PCR subtraction technique was applied at implantation and inter-plantation sites on day 4. 5 of pregnancy in mice. Two novel Expressed Sequence Tags (ESTs ), EST8 and EST81 were identified; their expression in tissues was analyzed by Northern blotting, and their full-length cDNAs were synthesized by PCR.Results We found that these two novel ESTs (EST8and EST81) were noticeably expressed in implantation site in the mouse on day 4. 5 of pregnancy. EST8 was expressed at high level in livers and implantation sites of the mice, while at low level in ovaries and inter-plantation sites. EST81 was predominantly expressed in implantation site and ovary, and at low level in all other tissues. Their complete cDNAs, 1 665bp and 1 264 bp respectively, were synthesized by using PCR.Conclusion The two full-length cDNAs were responsible for embryo implantation,and their functions need to be further studied.

  4. [Gene expression profiling by suppression subtractive hybridization (SSH): a example for its application to the study of lymphomas].

    Science.gov (United States)

    Villalva, C; Trempat, P; Zenou, R C; Delsol, G; Brousset, P

    2001-03-01

    Suppression subtractive hybridization (SSH) was used to isolate genes that were differentially expressed in anaplastic lymphoma kinase (ALK)-positive and ALK-negative anaplastic large cell lymphoma. In addition, this approach was applied to Hodgkin's disease cases with different clinical outcomes. SSH combines a normalization step that equalizes the abundance of cDNAs within the sequences to be tested and a subtraction step that excludes the common sequences between the target and the control. In a model system, the SSH technique enriches for rare sequences up to 5,000-fold in one round. We have isolated several genes whose expression varied significantly with regard to the tumour subtypes. There were different genes with known or unknown functions. We aim to compare the results of the SSH approach with those obtained with high density filters. In a near future, we would like to design DNA chips specific of each pathology that could be used for clinical purposes (evaluation of prognosis and therapeutic response).

  5. Dynamic graded subtraction: a simple method to background correct and display multicompartmental radiopharmaceutical scintigrams

    Energy Technology Data Exchange (ETDEWEB)

    Tuscan, M.J.; Wahl, R.L.; Botti, J.

    1985-09-01

    A common procedure to enhance the localization of a poorly localized radiopharmaceutical is to mimic and subtract its undesirable component with a second radionuclide of a different photopeak that is physiologic nonspecific. Determination of the exact amount of the nonspecific radionuclide to subtract in a single step, however, is difficult. The authors describe the use of a simple method to enhance an image of a poorly localized radiopharmaceutical by incrementally subtracting another image of a specific radiopharmaceutical that mimics the objectionable image data and displays the corrected image series in cinematic mode. This method of image correction and dynamic display may be useful for a variety of procedures in which there is a significant nonspecific component of the radiotracer such as in radiolabeled antibodies, or to perform selective compartmental or organ subtraction in the case of a mixed specificity radiopharmaceutical.

  6. Tailed pooled suppression subtractive hybridization (PSSH) adaptors do not alter efficiency.

    Science.gov (United States)

    Gerrish, Robert S; Gill, Steven R

    2010-11-01

    Suppression Subtractive Hybridization (SSH) and its derivative, Pooled Suppression Subtractive hybridization (PSSH), are powerful tools used to study variances larger than ~100 bp in prokaryotic genome structure. The initial steps involve ligating an oligonucleotide of known sequence (the "adaptor") to a fragmented genome to facilitate amplification, subtraction and downstream sequencing. SSH results in the creation of a library of unique DNA fragments which have been traditionally analyzed via Sanger sequencing. Numerous next generation sequencing technologies have entered the market yet SSH is incompatible with these platforms. This is due to the high level of sequence conservation of the oligonucleotide used for SSH. This rigid adherence is partly because it has yet to be determined if alteration of this oligonucleotide will have a deleterious impact on subtraction efficiency. The subtraction occurs when non-unique fragments are inhibited by a secondary self-pairing structure which requires exact nucleotide sequence. We determine if appending custom sequence to the 5' terminal ends of these oligonucleotides during the nested PCR stages of PSSH will reduce subtraction efficiency. We compare a pool of ten S. aureus clinical isolates with a standard PSSH and custom tailed-PSSH. We detected no statistically significant difference between their subtraction efficiencies. Our observations suggest that the adaptor's terminal ends may be labeled during the nested PCR step. This produces libraries labeled with custom sequence. This does not lead to loss of subtraction efficiency and would be invaluable for groups wishing to combine SSH or PSSH with their own downstream applications, such as a high throughput sequencing platform.

  7. Design of a Floating-Point Fused Add-Subtract Unit Using Verilog

    Directory of Open Access Journals (Sweden)

    Mayank Sharma,

    2013-06-01

    Full Text Available A floating-point (FP fused add-subtract unit is presented that performs simultaneous floating-point operation of add-subtract on a common pair of single-precision data at the same time that it takes to perform in a single addition with a conventional floating-point adder. The system was placed and routed in 45nm process so that there will be less consumption of memory as well as power.

  8. Diversity Suppression-Subtractive Hybridization Array for Profiling Genomic DNA Polymorphisms

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Genomic DNA polymorphisms are very useful for tracing genetic traits and studying biological diversity among species. Here, we present a method we call the "diversity suppression-subtractive hybridization array" for effectively profiling genomic DNA polymorphisms. The method first obtains the subtracted gDNA fragments between any two species by suppression subtraction hybridization (SSH) to establish a subtracted gDNA library,from which diversity SSH arrays are created with the selected subtracted clones. The diversity SSH array hybridizes with the DIG-labeled genomic DNA of the organism to be assayed. Six closely related Dendrobium species were studied as model samples. Four Dendrobium species as testers were used to perform SSH. A total of 617 subtracted positive clones were obtained from four Dendrobium species, and the average ratio of positive clones was 80.3%. We demonstrated that the average percentage of polymorphic fragments of pairwise comparisons of four Dendrobium species was up to 42.4%. A dendrogram of the relatedness of six Dendrobium species was produced according to their polymorphic profiles. The results revealed that the diversity SSH array is a highly effective platform for profiling genomic DNA polymorphisms and dendrograms.

  9. Young children's use of derived fact strategies in addition and subtraction

    Directory of Open Access Journals (Sweden)

    Ann eDowker

    2014-01-01

    Full Text Available 44 children between 6;0 and 7;11 took part in a study of derived fact strategy use. They were assigned to addition and subtraction levels on the basis of calculation pretests. They were then given Dowker’s (1998 test of derived fact strategies in addition, involving strategies based on the Identity, Commutativity, Addend + 1,Addend −1, and addition/subtraction Inverse principles; and test of derived fact strategies in subtraction, involving strategies based on the Identity, Minuend +1, Minuend -1, Subtrahend +1, Subtrahend -1, Complement and addition/subtraction Inverse principles. The exact arithmetic problems given varied according to the child’s previously assessed calculation level and were selected to be just a little too difficult for the child to solve unaided. Children were given the answer to a problem and then asked to solve another problem that could be solved quickly by using this answer, together with the principle being assessed. The children also took the WISC Arithmetic subtest. Strategies differed greatly in difficulty, with Identity being the easiest, and the Inverse and Complement principles being most difficult. The Subtrahend + 1 and Subtrahend – 1 problems often elicited incorrect strategies based on an overextension of the principles of addition to subtraction. It was concluded that children may have difficulty with understanding and applying the relationships between addition and subtraction. Derived fact strategy use was significantly related to both calculation level and to WISC Arithmetic scaled score.

  10. Value of blood-pool subtraction in cardiac indium-111-labeled platelet imaging

    Energy Technology Data Exchange (ETDEWEB)

    Machac, J.; Vallabhajosula, S.; Goldman, M.E.; Goldsmith, S.J.; Palestro, C.; Strashun, A.; Vaquer, R.; Phillips, R.A.; Fuster, V. (Mt. Sinai Medical Center, New York, NY (USA))

    1989-09-01

    Blood-pool subtraction has been proposed to enhance {sup 111}In-labeled platelet imaging of intracardiac thrombi. We tested the accuracy of labeled platelet imaging, with and without blood-pool subtraction, in ten subjects with cardiac thrombi of varying age, eight with endocarditis being treated with antimicrobial therapy and ten normal controls. Imaging was performed early after labeled platelet injection (24 hr or less) and late (48 hr or more). Blood-pool subtraction was carried out. All images were graded subjectively by four experienced, blinded readers. Detection accuracy was measured by the sensitivity at three fixed levels of specificity estimated from receiver operator characteristic curve analysis and tested by three-way analysis of variance. Detection accuracy was generally improved on delayed images. Blood-pool subtraction did not improve accuracy. Although blood-pool subtraction increased detection sensitivity, this was offset by decreased specificity. For this population studied, blood-pool subtraction did not improve subjective detection of abnormal platelet deposition by 111In platelet imaging.

  11. A computer-aided diagnosis system to detect pathologies in temporal subtraction images of chest radiographs

    Science.gov (United States)

    Looper, Jared; Harrison, Melanie; Armato, Samuel G.

    2016-03-01

    Radiologists often compare sequential radiographs to identify areas of pathologic change; however, this process is prone to error, as human anatomy can obscure the regions of change, causing the radiologists to overlook pathology. Temporal subtraction (TS) images can provide enhanced visualization of regions of change in sequential radiographs and allow radiologists to better detect areas of change in radiographs. Not all areas of change shown in TS images, however, are actual pathology. The purpose of this study was to create a computer-aided diagnostic (CAD) system that identifies which regions of change are caused by pathology and which are caused by misregistration of the radiographs used to create the TS image. The dataset used in this study contained 120 images with 74 pathologic regions on 54 images outlined by an experienced radiologist. High and low ("light" and "dark") gray-level candidate regions were extracted from the images using gray-level thresholding. Then, sampling techniques were used to address the class imbalance problem between "true" and "false" candidate regions. Next, the datasets of light candidate regions, dark candidate regions, and the combined set of light and dark candidate regions were used as training and testing data for classifiers by using five-fold cross validation. Of the classifiers tested (support vector machines, discriminant analyses, logistic regression, and k-nearest neighbors), the support vector machine on the combined candidates using synthetic minority oversampling technique (SMOTE) performed best with an area under the receiver operating characteristic curve value of 0.85, a sensitivity of 85%, and a specificity of 84%.

  12. Simple partial status epilepticus localized by single-photon emission computed tomography subtraction in chronic cerebral paragonimiasis.

    Science.gov (United States)

    Joo, Eun Yeon; Kim, Jee Hyun; Tae, Woo Suk; Han, Sun Jung; Kim, Seunghwan; Kim, Myoung-Hee; Byun, Hong Sik; Hong, Seung Bong

    2004-10-01

    A patient with chronic cerebral paragonimiasis began to have new motor seizures of the right face manifested by clonic contractions that occurred several hundred times a day, consistent with simple partial status epilepticus. Ictal electroencephalogram discharges started from the left frontal region and then spread to the left hemisphere with left frontal maximum. But clinical seizures were limited to the right face. The frequent partial seizures were controlled by the intravenous infusion of phenytoin. Brain magnetic resonance imaging showed multiple conglomerated round nodules with encephalomalacia in the left temporal and occipital lobes. Applying the technique of ictal-interictal single-photo emission computed tomography subtraction, the authors were able to localize the focal ictal-hyperperfusion on left precentral cortex adjacent to the lesions that correspond to the anatomical distribution of left face motor area.

  13. 320-Multidetector row whole-head dynamic subtracted CT angiography and whole-brain CT perfusion before and after carotid artery stenting: Technical note

    Energy Technology Data Exchange (ETDEWEB)

    San Millan Ruiz, Diego, E-mail: dsanmil1@jhmi.ed [Division of Interventional Neuroradiology, Department of Radiology, Johns Hopkins Hospital, 600 North Wolfe Street, B-100, Baltimore, MD 21287 (United States); Murphy, Kieran, E-mail: KMURPHY@jhmi.ed [Division of Interventional Neuroradiology, Department of Radiology, The Johns Hopkins Hospital, 600 North Wolfe Street, B-100, Baltimore, MD 21287 (United States); Gailloud, Philippe, E-mail: pgailloud@cerebrovascular.ne [Division of Interventional Neuroradiology, Department of Radiology, Johns Hopkins Hospital, 600 North Wolfe Street, B-100, Baltimore, MD 21287 (United States)

    2010-06-15

    Introduction: Multidetector CT (MDCT) is increasingly used for the investigation of neurovascular disorders, but restricted z-axis coverage (3.2 cm for 64-MDCT) currently limits perfusion to a small portion of the brain close to the circle of Willis, and precludes dynamic angiographic appreciation of the entire brain circulation. We illustrate the clinical potential of recently developed 320-MDCT extending the z-axis coverage to 16 cm in a patient with symptomatic carotid artery stenosis. Methods: In a 74-year-old patient presenting with critical symptomatic stenosis of the left CCA, pre- and post-carotid artery stenting whole-head subtracted dynamic MDCT angiography and perfusion were obtained in addition to CT angiography of the supra-aortic trunks. Both whole-head subtracted MDCT angiography and perfusion demonstrated delayed left ICA circulation, which normalized after carotid stenting. Discussion: 320-MDCT offers unprecedented z-axis coverage allowing for whole-brain perfusion and subtracted dynamic angiography of the entire intracranial circulation. These innovations can consolidate the role of MDCT as a first intention imaging technique for cerebrovascular disorders, in particular for the acute management of stroke.

  14. [Cold induced cDNA library construction of highland barley (Hordeum vulgare L. var. nudum Hk. f.) using suppression subtractive hybridization technology].

    Science.gov (United States)

    He, Tao; Jia, Jing Fen

    2008-12-01

    Cold-induced genes of highland barley (Hordeum vulgare L. var. nudum Hk. f.) were studied using suppression subtractive hybridization (SSH) technique. The cDNA from the materials treated with 4 degrees C was used as "tester", and that from the materials growing in green house (20+/-2 degrees C) as "driver". A subtractive library of highland barley including 640 cDNA clones was constructed in this study. Enzyme digestion of 32 clones chosen randomly from the library indicated that 87.5% of them contained inserts. The cDNA inserts of 16 clones were sequenced. Blast search analyses showed that these cDNAs were homologies to genes encoding the following proteins: metallothionein, protein kinase, ethylene signal transcription factor, bZIP transcription factor, zing finger transcription factor, ribulose-1,5-bisphosphate carboxylase, ribosomal protein, sodium: hydrogen antiporter, catalase, NADPH-cytochrome reductase, ascorbate peroxidase, DNA binding protein, and sugar transporter-like protein. These results indicated that the cDNA clones in the library were related to cold-induced genes, and suggested that the cold-tolerant mechanism of highland barley might be a complicated, interactive system involving multiple approaches and genes. Construction of subtractive cDNA library provided an advantage for further studies to isolate and clone cold-induced genes in highland barley.

  15. WAXS fat subtraction model to estimate differential linear scattering coefficients of fatless breast tissue: Phantom materials evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Robert Y., E-mail: rx-tang@laurentian.ca [Biomolecular Sciences Program, Laurentian University, 935 Ramsey Lake Road, Sudbury, Ontario P3E 2C6 (Canada); Laamanen, Curtis, E-mail: cx-laamanen@laurentian.ca; McDonald, Nancy, E-mail: mcdnancye@gmail.com [Department of Physics, Laurentian University, 935 Ramsey Lake Road, Sudbury, Ontario P3E 2C6 (Canada); LeClair, Robert J., E-mail: rleclair@laurentian.ca [Department of Physics, Laurentian University, 935 Ramsey Lake Road, Sudbury, Ontario P3E 2C6, Canada and Biomolecular Sciences Program, Laurentian University, 935 Ramsey Lake Road, Sudbury, Ontario P3E 2C6 (Canada)

    2014-05-15

    Purpose: Develop a method to subtract fat tissue contributions to wide-angle x-ray scatter (WAXS) signals of breast biopsies in order to estimate the differential linear scattering coefficients μ{sub s} of fatless tissue. Cancerous and fibroglandular tissue can then be compared independent of fat content. In this work phantom materials with known compositions were used to test the efficacy of the WAXS subtraction model. Methods: Each sample 5 mm in diameter and 5 mm thick was interrogated by a 50 kV 2.7 mm diameter beam for 3 min. A 25 mm{sup 2} by 1 mm thick CdTe detector allowed measurements of a portion of the θ = 6° scattered field. A scatter technique provided means to estimate the incident spectrum N{sub 0}(E) needed in the calculations of μ{sub s}[x(E, θ)] where x is the momentum transfer argument. Values of μ{sup ¯}{sub s} for composite phantoms consisting of three plastic layers were estimated and compared to the values obtained via the sum μ{sup ¯}{sub s}{sup ∑}(x)=ν{sub 1}μ{sub s1}(x)+ν{sub 2}μ{sub s2}(x)+ν{sub 3}μ{sub s3}(x), where ν{sub i} is the fractional volume of the ith plastic component. Water, polystyrene, and a volume mixture of 0.6 water + 0.4 polystyrene labelled as fibphan were chosen to mimic cancer, fat, and fibroglandular tissue, respectively. A WAXS subtraction model was used to remove the polystyrene signal from tissue composite phantoms so that the μ{sub s} of water and fibphan could be estimated. Although the composite samples were layered, simulations were performed to test the models under nonlayered conditions. Results: The well known μ{sub s} signal of water was reproduced effectively between 0.5 < x < 1.6 nm{sup −1}. The μ{sup ¯}{sub s} obtained for the heterogeneous samples agreed with μ{sup ¯}{sub s}{sup ∑}. Polystyrene signals were subtracted successfully from composite phantoms. The simulations validated the usefulness of the WAXS models for nonlayered biopsies. Conclusions: The methodology to

  16. Pedal angiography in peripheral arterial occlusive disease: first-pass i.v. contrast-enhanced MR angiography with blood pool contrast medium versus intraarterial digital subtraction angiography.

    Science.gov (United States)

    Kos, Sebastian; Reisinger, Clemens; Aschwanden, Markus; Bongartz, Georg M; Jacob, Augustinus L; Bilecen, Deniz

    2009-03-01

    The purpose of this study was to prospectively evaluate first-pass i.v. gadofosveset-enhanced MR angiography in patients with peripheral arterial occlusive disease for visualization of the pedal arteries and stenosis or occlusion of those arteries with intraarterial digital subtraction angiography as the reference standard. Twenty patients with peripheral arterial occlusive disease (nine women, 11 men; age-range 58-83 years) were prospectively enrolled. Gadofosveset first-pass contrast-enhanced MR angiography was performed with a 1.5-T system, a dedicated foot coil, and cuff compression to the calf. Arterial segments were assessed for degree of arterial stenosis, arterial visibility, diagnostic utility, and venous contamination. Detection of vessel stenosis or occlusion was evaluated in comparison with findings at digital subtraction angiography. The unpaired Student's t test was used to test arterial visibility with the two techniques. First-pass MR angiography with gadofosveset had good diagnostic utility in 83.9% of all segments and no venous contamination in 96.8% of all segments. There was no difference between the performance of intraarterial digital subtraction angiography and that of i.v. contrast-enhanced MR angiography in arterial visibility overall (p = 0.245) or in subgroup analysis of surgical arterial bypass targets (p = 0.202). The overall sensitivity, specificity, and accuracy of i.v. gadofosveset-enhanced MR angiography for characterization of clinically significant stenosis and occlusion were 91.4%, 96.1%, and 93.9%. In the subgroup analysis, the sensitivity, specificity, and accuracy were 85.5%, 96.5%, and 92.1%. Gadofosveset-enhanced MR angiography of the pedal arteries in patients with peripheral arterial occlusive disease has arterial visibility equal to that of digital subtraction angiography and facilitates depiction of clinically significant stenosis and occlusion.

  17. Subtraction-multiphase-CT unbeneficial for early detection of colorectal liver metastases

    Energy Technology Data Exchange (ETDEWEB)

    Meijerink, Martijn R., E-mail: mr.meijerink@vumc.n [Department of Radiology, Vrije Universiteit Medisch Centrum, Amsterdam (Netherlands); Waesberghe, Jan Hein T.M. van; Golding, Richard P. [Department of Radiology, Vrije Universiteit Medisch Centrum, Amsterdam (Netherlands); Weide, Lineke van der [Master of Oncology Program, Vrije Universiteit Medisch Centrum, Amsterdam (Netherlands); Tol, Petrousjka van den [Department of Surgical Oncology, Vrije Universiteit Medisch Centrum, Amsterdam (Netherlands); Meijer, Sybren [Master of Oncology Program, Vrije Universiteit Medisch Centrum, Amsterdam (Netherlands); Kuijk, Cornelis van [Department of Radiology, Vrije Universiteit Medisch Centrum, Amsterdam (Netherlands)

    2010-06-15

    Purpose: To assess the value of multiphase-subtraction-CT for early detection of colorectal-liver-metastases (CRLM). Methods and materials: In 50 patients suspected of CRLM a routine pre-operative 4-phase-CT-scan of the upper abdomen was obtained. All 12 possible image subtractions between two different phases were constructed applying 3D-image-registration to decrease distortion artefacts induced by differences in inspiration volume. Two experienced radiologists initially reviewed the conventional 4-phase-CT for malignant and/or benign appearing lesions and at least 1-month hereafter the same 4-phase-CT now including the subtracted images. The results were compared to histology reports or to a combination of surgical exploration and intraoperative ultrasound together with results from pre-operative PET and follow-up examinations. Results: Although an additional number of 31 malignant appearing lesions were detected on the subtraction images, none proved to represent a true CRLM. Interobserver agreement ({kappa}) decreased from 0.627 (good) to 0.418 (fair). Conclusion: Adding linearly co-registered subtraction-CT images to a conventional 4-phase-CT protocol does not improve detection of CRLM.

  18. Identification of differentially expressed radiation-induced genes in cervix carcinoma cells using suppression subtractive hybridization

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jun Sang; Lee, Young Sook; Lee, Jeung Hoon; Lee, Woong Hee; Seo, Eun Young; Cho, Moon June [Chungnam National University, Daejeon (Korea, Republic of)

    2005-03-15

    A number of genes and their products are induced early or late following exposure of cells to ionizing radiation. These radiation-induced genes have various effects of irradiated cells and tissues. Suppression subtractive hybridization (SSH) based on PCR was used to identify the differentially expressed genes by radiation in cervix carcinoma cells. Total RNA and poly (A){sup +} mRNA were isolated from irradiated and non-irradiated HeLa cells. Forward-and reverse-subtracted cDNA libraries were constructed using SSH. Eighty-eight clones of each were used to randomly select differentially expressed genes using reverse Northern blotting (dot blot analysis). Northern blotting was used to verify the screened genes. Of the 176 clones, 10 genes in the forward-subtracted library and 9 genes in the reverse-subtracted library were identified as differentially expressed radiation-induced genes by PCR-select differential screening. Three clones from the forward-subtracted library were confirmed by Northern blotting, and showed increased expression in a dose-dependent manner, including a telomerase catalytic subunit and sodium channel-like protein gene, and an ESTs (expressed sequence tags) gene. We identified differentially expressed radiation-induced genes with low-abundance genes with SSH, but further characterization of theses genes are necessary to clarify the biological functions of them.

  19. L5 pedicle subtraction osteotomy for high-grade isthmic spondylolisthesis.

    Science.gov (United States)

    Radcliff, Kristen E; Jakoi, Andre M

    2015-04-01

    To the authors' knowledge, this is the first article to present a pedicle subtraction osteotomy in the lumbar spine to correct and stabilize a high-grade isthmic spondylolisthesis, which poses many challenges with regard to treatment options and outcomes. The optimal surgical treatment for high-grade spondylolisthesis is controversial, but the goals of treatment are to stabilize the affected spinal levels and to decompress the neural elements. A pedicle subtraction osteotomy is a reconstructive procedure that addresses fixed sagittal imbalance by increasing lumbar lordosis through posterior spinal column shortening. The authors report a 46-year-old patient with chronic, progressively worsening back and leg radiculopathy accompanied by sagittal plane malalignment and for which a pedicle subtraction osteotomy was performed. The procedure yielded stabilization of the patient's lumbar spondylolisthesis and sagittal plane alignment was restoration. At 3 months postoperatively, the patient's pain had fully resolved and her motor and neurologic examination exhibited no deficits. At 24 months postoperatively, she was still symptom-free and ambulating without assistance. This report is the first documented successful pedicle subtraction osteotomy in the treatment of high-grade spondylolisthesis. This report indicates that certain patient populations may be amenable to pedicle subtraction osteotomy as a treatment option for pathology involving high-grade isthmic spondylolisthesis.

  20. A practical method for randoms subtraction in volume imaging PET from detector singles countrate measurements

    Energy Technology Data Exchange (ETDEWEB)

    Smith, R.J.; Karp, J.S. [Univ. of Pennsylvania, Philadelphia, PA (United States). Dept. of Radiology

    1996-06-01

    Randoms subtraction in a volume imaging PET scanner is a significant problem due to the high singles countrates experienced. The delayed coincidence method requires double counting of randoms events and results in a lowered countrate capability. Calculations based on detector singles countrates require complex corrections for countrate dependent livetime and event acceptance due to the camera coincidence processing between the detector and rebinned randoms countrates. The profile distribution method has been used to estimate and subtract both scatter and randoms background but this method is a compromise and couples these 2 sources of background together. In order to avoid these problems and provide accurate subtraction of both the distribution and magnitude of randoms contamination in the scan data the authors have developed an alternative singles based method. The singles distributions are measured across the detectors and are used to construct a randoms distribution sinogram. This distribution is scaled to the appropriate rebinned randoms countrate by means of a lookup table of randoms countrate vs detector singles countrate, generated from phantom calibrations. The advantages of performing randoms subtraction by this method are: (1) there is no increase in camera deadtime, (2) the method compensates for nonuniformities in randoms distributions due to both the activity distribution and nonuniform geometric response of the camera for on and off bankpairs, and (3) it deals with randoms subtraction independently of scatter so that different scatter correction routines may then be applied to the data.

  1. Tumor scintigraphy by the method for subtracting the initial image with technetium-99m labeled antibody

    Energy Technology Data Exchange (ETDEWEB)

    Karube, Yoshiharu; Katsuno, Kentaro; Ito, Sanae; Matsunaga, Kazuhisa; Takata, Jiro [Fukuoka Univ. (Japan). Faculty of Pharmaceutical Sciences; Kuroki, Masahide; Murakami, Masaaki; Matsuoka, Yuji

    1999-12-01

    The method for subtracting the initial image from the localization image was evaluated for radioimmunoscintigraphy of tumors with technetium-99m (Tc-99m) labeled antibodies. Monoclonal antibodies were parental mouse and mouse-human chimeric antibodies to carcinoembryonic antigen (CEA), designated F11-39 and ChF11-39, respectively, both of which have been found to discriminate CEA in tumor tissues from the CEA-related antigens. After reduction of the intrinsic disulfide bonds, these antibodies were labeled with Tc-99m. In vivo studies were performed on athymic nude mice bearing the human CEA-producing gastric carcinoma xenografts. Though biodistribution results showed selective and progressive accumulation of Tc-99m labeled antibodies at the tumor site, high radioactivity in blood was inappropriate for scintigraphic visualization of the tumors within a few hours. We examined the subtraction of the initial Tc-99m image from the Tc-99m localization image after a few hours. Subtracted images of the same count reflected the in vivo behavior of the Tc-99m radioactivity. The subtracted scintigrams revealed excellent tumor images with no significant extrarenal background. Visualization of the tumor site was dependent on antigen-specific binding and nonspecific exudation. These results demonstrate that a method of subtraction of the initial image may serve as a potentially useful diagnostic method for an abnormal site for agents with a low pharmacokinetic value. (author)

  2. Phantom evaluation of simultaneous thallium-201/technetium-99m acquisition in single-photon emission tomography

    Energy Technology Data Exchange (ETDEWEB)

    Cao Zongjian [Department of Diagnostic Radiology, University of Maryland Medical Center, Baltimore, MD (United States); Chen, C.C. [Department of Diagnostic Radiology, University of Maryland Medical Center, Baltimore, MD (United States); Maunoury, C. [Department of Diagnostic Radiology, University of Maryland Medical Center, Baltimore, MD (United States); Holder, L.E. [Department of Diagnostic Radiology, University of Maryland Medical Center, Baltimore, MD (United States); Abraham, T.C. [Department of Diagnostic Radiology, University of Maryland Medical Center, Baltimore, MD (United States); Tehan, A. [Department of Diagnostic Radiology, University of Maryland Medical Center, Baltimore, MD (United States)

    1996-11-01

    This study investigated downscatter effects in cardiac single-photon emission tomographic studies with simultaneous thallium-201/technetium-99m acquisition, and evaluated a previously proposed subtraction technique for downscatter compensation. Ten studies were carried out with different defect sizes and locations and varying activity distributions using four energy windows: 70{+-}10% keV, 140{+-}10% keV, 100{+-}10% KeV, and 103{+-}16% keV. The subtraction technique used the 100- or 103-keV data to remove scattered {sup 99m}Tc counts from the 70-keV data. The size and contrast of infarcts in the dual-isotope 70-keV image were artificially decreased compared to those in the 140-keV image, caused by scattered {sup 99m}Tc counts that were comparable to the primary {sup 201}Tl counts in the 70-keV window. The subtraction technique produced larger defects and more heterogeneous activity in the myocardial wall in dual-isotope 70-keV images compared to the corresponding {sup 201}Tl-only images. These artifacts were caused by the markedly different spatial distributions of scattered {sup 99m}Tc counts in the 100-keV (or 103-keV) window as compared with the 70-keV window. It is concluded that scattered {sup 99m}Tc photons may cause overestimation of ischemia and myocardial viability in simultaneous dual-isotope patient studies. The proposed subtraction technique was inaccurate and produced image artifacts. Adequate downscatter compensation methods must be developed before applying simultaneous {sup 201}Tl/{sup 99m}Tc acquisition in clinical practice. (orig.). With 6 figs., 3 tabs.

  3. Suppression Subtractive Hybridization Versus Next-Generation Sequencing in Plant Genetic Engineering: Challenges and Perspectives.

    Science.gov (United States)

    Sahebi, Mahbod; Hanafi, Mohamed M; Azizi, Parisa; Hakim, Abdul; Ashkani, Sadegh; Abiri, Rambod

    2015-10-01

    Suppression subtractive hybridization (SSH) is an effective method to identify different genes with different expression levels involved in a variety of biological processes. This method has often been used to study molecular mechanisms of plants in complex relationships with different pathogens and a variety of biotic stresses. Compared to other techniques used in gene expression profiling, SSH needs relatively smaller amounts of the initial materials, with lower costs, and fewer false positives present within the results. Extraction of total RNA from plant species rich in phenolic compounds, carbohydrates, and polysaccharides that easily bind to nucleic acids through cellular mechanisms is difficult and needs to be considered. Remarkable advancement has been achieved in the next-generation sequencing (NGS) field. As a result of progress within fields related to molecular chemistry and biology as well as specialized engineering, parallelization in the sequencing reaction has exceptionally enhanced the overall read number of generated sequences per run. Currently available sequencing platforms support an earlier unparalleled view directly into complex mixes associated with RNA in addition to DNA samples. NGS technology has demonstrated the ability to sequence DNA with remarkable swiftness, therefore allowing previously unthinkable scientific accomplishments along with novel biological purposes. However, the massive amounts of data generated by NGS impose a substantial challenge with regard to data safe-keeping and analysis. This review examines some simple but vital points involved in preparing the initial material for SSH and introduces this method as well as its associated applications to detect different novel genes from different plant species. This review evaluates general concepts, basic applications, plus the probable results of NGS technology in genomics, with unique mention of feasible potential tools as well as bioinformatics.

  4. Identification of two novel nodule-specific genes from Astragalus sinicus L. by suppressive subtractive hybridization

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    To identify the genes involved in nodule formation and to increase usable molecular probes, a cDNA library of Astragalus sinicus genes specifically expressed in infected roots by Mesorhizobium huakuii 7653R is generated using a PCR-based suppressive subtractive hybridization (SSH) technique with two mRNA populations of infected and uninfected control roots. Two nodule-specific genes, AsIIC259 and AsG2511, are identified from infected roots of A. sinicus. The amino acid sequences deduced from the open reading frames (ORFs) reveal that AsIIC259 and AsG2511 encodes a polypeptide with 134 and 58 amino acids, respectively. A signal peptide sequence is predicted with high probability at the N-termini of the AsIIC259 and AsG2511. The motif searches show that the deduced polypeptide of AsIIC259 contains two N-glycosylation sites, a cAMP- and cGMP-dependent protein kinase phosphorylation site and a casein kinase II phosphorylation site. BLASTP searches reveal that AsIIC259 putative protein displays a low degree of similarity to a unique nodulin from Lupinus luteus nodules. No significant identity is displayed over the predicted polypeptides of AsG2511 with any published sequences. Virtual Northern blot and semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) analyses indicate that the two genes are expressed exclusively in inoculated roots and that their expression is 2-4 d later than that of the leghaemoglobin (Lb) gene during nodule development.

  5. Using adaptive neuro-fuzzy inference system technique for crosstalk correction in simultaneous {sup 99m}Tc/{sup 201}Tl SPECT imaging: A Monte Carlo simulation study

    Energy Technology Data Exchange (ETDEWEB)

    Heidary, Saeed, E-mail: saeedheidary@aut.ac.ir; Setayeshi, Saeed, E-mail: setayesh@aut.ac.ir

    2015-01-11

    This work presents a simulation based study by Monte Carlo which uses two adaptive neuro-fuzzy inference systems (ANFIS) for cross talk compensation of simultaneous {sup 99m}Tc/{sup 201}Tl dual-radioisotope SPECT imaging. We have compared two neuro-fuzzy systems based on fuzzy c-means (FCM) and subtractive (SUB) clustering. Our approach incorporates eight energy-windows image acquisition from 28 keV to 156 keV and two main photo peaks of {sup 201}Tl (77±10% keV) and {sup 99m}Tc (140±10% keV). The Geant4 application in emission tomography (GATE) is used as a Monte Carlo simulator for three cylindrical and a NURBS Based Cardiac Torso (NCAT) phantom study. Three separate acquisitions including two single-isotopes and one dual isotope were performed in this study. Cross talk and scatter corrected projections are reconstructed by an iterative ordered subsets expectation maximization (OSEM) algorithm which models the non-uniform attenuation in the projection/back-projection. ANFIS-FCM/SUB structures are tuned to create three to sixteen fuzzy rules for modeling the photon cross-talk of the two radioisotopes. Applying seven to nine fuzzy rules leads to a total improvement of the contrast and the bias comparatively. It is found that there is an out performance for the ANFIS-FCM due to its acceleration and accurate results.

  6. Preclinical animal research on therapy dosimetry with dual isotopes

    NARCIS (Netherlands)

    M.W. Konijnenberg (Mark); M. de Jong (Marion)

    2011-01-01

    textabstractPreclinical research into radionuclide therapies based on radiation dosimetry will enable the use of any LET-equivalent radionuclide. Radiation dose and dose rate have significant influence on dose effects in the tumour depending on its radiation sensitivity, possibilities for repair of

  7. Preclinical animal research on therapy dosimetry with dual isotopes

    NARCIS (Netherlands)

    M.W. Konijnenberg (Mark); M. de Jong (Marion)

    2011-01-01

    textabstractPreclinical research into radionuclide therapies based on radiation dosimetry will enable the use of any LET-equivalent radionuclide. Radiation dose and dose rate have significant influence on dose effects in the tumour depending on its radiation sensitivity, possibilities for repair of

  8. Clinical evaluation of intravenous digital subtraction angiography in chest diseases in the elderly

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, Kazuhide; Adachi, Satoru; Suzuki, Kanzo and others

    1988-01-01

    To evaluate the image quality, we performed intravenous digital subtraction angiography for various chest diseases in 62 elderly subjects. In large vessel diseases in the chest, adequate imaging was possible in most cases, especially in the main, right and left pulmonary artery and the aorta. However, second order (subsegmental) and more distal order branches were sometimes judged unsatisfactory because of poor image quality. Five cases were evaluated as inadequate because of motion, i.e. respiratory or cardiac movement. The pulmonary circulating time was measured by the time density curve of the pulmonary artery and vein by digital subtraction angiography, and converse correlation between pulmonary circulating time and cardiac index was obtained. Thus it was possible to evaluate the pulmonary circulating dynamics. As mentioned above, intravenous digital subtraction angiography was a useful and safe method for chest diseases, especially in evaluation of large vessels in the elderly.

  9. Enrichment of an in vivo phage display repertoire by subtraction for easy identification of pathology biomarkers

    Directory of Open Access Journals (Sweden)

    karina Vargas Sanchez

    2015-03-01

    Conclusion. This physical subtraction discarded from a complex repertoire the non-specific selected ligands. STRATEGY 1 Three rounds of in vivo phage peptide selection in EAE female Lewis rats ("EAE repertoire" vs controls ("HEALTHY repertoire". 2 DNA subtraction of the most common sequences between «HEALTHY» and «EAE» phage repertoires to obtain a third EAE specific «SUBTRACTION » phage repertoire. 3 Massive sequencing of the three repertoires and bioinformatic analysis to identify the peptides sequences with high EAE specificity. 4 Biological tests of potential EAE specific phage clones with CNS tissues from EAE and Healthy control rats. 5 Biological tests of the EAE specific peptide and phage clones on the BBB in vitro model (hCMEC/D3 cells under inflammatory conditions (IL-1β stimulation. 6 Target separation and identification by cross-link between the selected phage clones and hMEC/D3 endothelial cells targets under IL-1β stimulation vs controls.

  10. [The backgroud sky subtraction around [OIII] line in LAMOST QSO spectra].

    Science.gov (United States)

    Shi, Zhi-Xin; Comte, Georges; Luo, A-Li; Tu, Liang-Ping; Zhao, Yong-Heng; Wu, Fu-Chao

    2014-11-01

    At present, most sky-subtraction methods focus on the full spectrum, not the particular location, especially for the backgroud sky around [OIII] line which is very important to low redshift quasars. A new method to precisely subtract sky lines in local region is proposed in the present paper, which sloves the problem that the width of Hβ-[OIII] line is effected by the backgroud sky subtraction. The exprimental results show that, for different redshift quasars, the spectral quality has been significantly improved using our method relative to the original batch program by LAMOST. It provides a complementary solution for the small part of LAMOST spectra which are not well handled by LAMOST 2D pipeline. Meanwhile, This method has been used in searching for candidates of double-peaked Active Galactic Nuclei.

  11. Spectral Subtraction Approach for Interference Reduction of MIMO Channel Wireless Systems

    Directory of Open Access Journals (Sweden)

    Tomohiro Ono

    2005-08-01

    Full Text Available In this paper, a generalized spectral subtraction approach for reducing additive impulsive noise, narrowband signals, white Gaussian noise and DS-CDMA interferences in MIMO channel DS-CDMA wireless communication systems is investigated. The interference noise reduction or suppression is essential problem in wireless mobile communication systems to improve the quality of communication. The spectrum subtraction scheme is applied to the interference noise reduction problems for noisy MIMO channel systems. The interferences in space and time domain signals can effectively be suppressed by selecting threshold values, and the computational load with the FFT is not large. Further, the fading effects of channel are compensated by spectral modification with the spectral subtraction process. In the simulations, the effectiveness of the proposed methods for the MIMO channel DS-CDMA is shown to compare with the conventional MIMO channel DS-CDMA.

  12. Perturbative subtraction of lattice artifacts in the computation of renormalization constants

    CERN Document Server

    Constantinou, M; Gockeler, M; Horsley, R; Panagopoulos, H; Perlt, H; Rakow, P E L; Schierholz, G; Schiller, A

    2012-01-01

    The determination of renormalization factors is of crucial importance. They relate the observables obtained on finite, discrete lattices to their measured counterparts in the continuum in a suitable renormalization scheme. Therefore, they have to be computed as precisely as possible. A widely used approach is the nonperturbative Rome-Southampton method. It requires, however, a careful treatment of lattice artifacts. They are always present because simulations are done at lattice spacings $a$ and momenta $p$ with $ap$ not necessarily small. In this paper we try to suppress these artifacts by subtraction of one-loop contributions in lattice perturbation theory. We compare results obtained from a complete one-loop subtraction with those calculated for a subtraction of $O(a^2)$.

  13. Titanium plate artefact mimicking popliteal artery dissection on digital subtraction CT angiography.

    Science.gov (United States)

    Woodacre, Timothy; Wienand-Barnett, Sophie

    2013-04-05

    Titanium plates used for the internal fixation of long bone fractures cause significant artefact on CT scans but have not been reported to affect digital subtraction CT angiography. We present a patient with clinical suspicion of popliteal artery injury following a high tibial osteotomy. The osteotomy was stabilised with a titanium locking plate. During the digital subtraction process used to produce reconstruction CT angiography, removal of artefact caused by the titanium plate produced CT images mimicking the appearance of a popliteal artery dissection. The imaging inaccuracy was realised prior to the patient undergoing further intervention. We highlight the potential error caused by titanium plates on digital subtraction CT angiography and recommend careful analysis of such images prior to further treatment.

  14. Optimal fractionation and bioassay plans for isolation of synergistic chemicals: The subtractive-combination method.

    Science.gov (United States)

    Byers, J A

    1992-09-01

    Studies of chemical ecology of an organism are founded on the isolation and identification of a semiochemical, often comprised of two or more synergistic compounds (each Synergist alone has little activity, but presented together they are bioactive). Chromatographie fractionation and bioassay methods of binary splitting, additive combination, and subtractive combination are compared for efficiency in isolating synergists. Formulas are derived for the latter two methods that calculate the expected number of bioassay tests required for isolation of from two to five synergists from biological extracts with any number of compounds, depending on the number of initial (major) Chromatographic fractions. A computer program based on the formulas demonstrates the superiority of the subtractive-combination method. Simulations with the program were used to determine the optimal number of initial fractions for the additive- and subtractive-combination methods when isolating two to five synergists from extracts of from 25 to 1200 compounds. Methods of bioassay, isolation, identification, and field testing of semiochemicals are discussed.

  15. Enhanced image reconstruction of three-dimensional fluorescent assays by subtractive structured-light illumination microscopy.

    Science.gov (United States)

    Choi, Jong-ryul; Kim, Donghyun

    2012-10-01

    We investigate improved image reconstruction of structured light illumination for high-resolution imaging of three-dimensional (3D) cell-based assays. For proof of concept, an in situ fluorescence optical detection system was built with a digital micromirror device as a spatial light modulator, for which phase and tilting angle in a grid pattern were varied to implement specific image reconstruction schemes. Subtractive reconstruction algorithms based on structured light illumination were used to acquire images of fluorescent microbeads deposited as a two-dimensional monolayer or in 3D alginate matrix. We have confirmed that an optical subtraction algorithm improves axial and lateral resolution by effectively removing out-of-focus fluorescence. The results suggest that subtractive image reconstruction can be useful for structured illumination microscopy of broad types of cell-based assays with high image resolution.

  16. The effects of camera jitter for background subtraction algorithms on fused infrared-visible video streams

    Science.gov (United States)

    Becker, Stefan; Scherer-Negenborn, Norbert; Thakkar, Pooja; Hübner, Wolfgang; Arens, Michael

    2016-10-01

    This paper is a continuation of the work of Becker et al.1 In their work, they analyzed the robustness of various background subtraction algorithms on fused video streams originating from visible and infrared cameras. In order to cover a broader range of background subtraction applications, we show the effects of fusing infrared-visible video streams from vibrating cameras on a large set of background subtraction algorithms. The effectiveness is quantitatively analyzed on recorded data of a typical outdoor sequence with a fine-grained and accurate annotation of the images. Thereby, we identify approaches which can benefit from fused sensor signals with camera jitter. Finally conclusions on what fusion strategies should be preferred under such conditions are given.

  17. Enhancing quantum entanglement for continuous variables by a coherent superposition of photon subtraction and addition

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Su-Yong; Kim, Ho-Joon [Department of Physics, Texas A and M University at Qatar, P.O. Box 23874, Doha (Qatar); Ji, Se-Wan [School of Computational Sciences, Korea Institute for Advanced Study, Seoul 130-012 (Korea, Republic of); Nha, Hyunchul [Department of Physics, Texas A and M University at Qatar, P.O. Box 23874, Doha (Qatar); Institute fuer Quantenphysik, Universitaet Ulm, D-89069 Ulm (Germany)

    2011-07-15

    We investigate how the entanglement properties of a two-mode state can be improved by performing a coherent superposition operation ta+ra{sup {dagger}} of photon subtraction and addition, proposed by Lee and Nha [Phys. Rev. A 82, 053812 (2010)], on each mode. We show that the degree of entanglement, the Einstein-Podolsky-Rosen-type correlation, and the performance of quantum teleportation can be all enhanced for the output state when the coherent operation is applied to a two-mode squeezed state. The effects of the coherent operation are more prominent than those of the mere photon subtraction a and the addition a{sup {dagger}} particularly in the small-squeezing regime, whereas the optimal operation becomes the photon subtraction (case of r=0) in the large-squeezing regime.

  18. Hand Gesture Recognition Using Modified 1$ and Background Subtraction Algorithms

    Directory of Open Access Journals (Sweden)

    Hazem Khaled

    2015-01-01

    Full Text Available Computers and computerized machines have tremendously penetrated all aspects of our lives. This raises the importance of Human-Computer Interface (HCI. The common HCI techniques still rely on simple devices such as keyboard, mice, and joysticks, which are not enough to convoy the latest technology. Hand gesture has become one of the most important attractive alternatives to existing traditional HCI techniques. This paper proposes a new hand gesture detection system for Human-Computer Interaction using real-time video streaming. This is achieved by removing the background using average background algorithm and the 1$ algorithm for hand’s template matching. Then every hand gesture is translated to commands that can be used to control robot movements. The simulation results show that the proposed algorithm can achieve high detection rate and small recognition time under different light changes, scales, rotation, and background.

  19. Subtraction of Spurious Centre-of-Mass Motion in Quark Delocalization and Colour Screening Model

    Institute of Scientific and Technical Information of China (English)

    CHEN Ling-Zhi; PANG Hou-Rong; HUANG Hong-Xia; PING Jia-Lun; WANG Fan

    2007-01-01

    The quark delocalization colour screening model provides an alternative approach for the NN intermediate range attraction, which is attributed to the σ meson exchange in the meson exchange and chiral quark model.However the quark delocalization induces the spurious centre-of-mass motion (CMM). A method for subtracting the spurious CMM proposed before is applied to the new scattering calculation. The subtraction of the spurious CMM results in an additional NN attraction. The NN scattering data are refitted by a fine tune of the colour screening constant.

  20. Similarity renormalization group evolution of N N interactions within a subtractive renormalization scheme

    Directory of Open Access Journals (Sweden)

    Durães F.O.

    2010-04-01

    Full Text Available We apply the similarity renormalization group (SRG approach to evolve a nucleon-nucleon (N N interaction in leading-order (LO chiral effective field theory (ChEFT, renormalized within the framework of the subtracted kernel method (SKM. We derive a fixed-point interaction and show the renormalization group (RG invariance in the SKM approach. We also compare the evolution of N N potentials with the subtraction scale through a SKM RG equation in the form of a non-relativistic Callan-Symanzik (NRCS equation and the evolution with the similarity cutoff through the SRG transformation.

  1. Higgs boson production in association with a jet using jettiness subtraction

    Directory of Open Access Journals (Sweden)

    Radja Boughezal

    2015-09-01

    Full Text Available We use the recently proposed jettiness-subtraction scheme to provide the complete calculation of Higgs boson production in association with a jet in hadronic collisions through next-to-next-to-leading order in perturbative QCD. This method exploits the observation that the N-jettiness event-shape variable completely describes the singularity structure of QCD when final-state colored particles are present. Our results are in agreement with a recent computation of the gg and qg partonic initial states based on sector-improved residue subtraction. We present phenomenological results for both fiducial cross sections and distributions at the LHC.

  2. A Feature Subtraction Method for Image Based Kinship Verification under Uncontrolled Environments

    DEFF Research Database (Denmark)

    Duan, Xiaodong; Tan, Zheng-Hua

    2015-01-01

    The most fundamental problem of local feature based kinship verification methods is that a local feature can capture the variations of environmental conditions and the differences between two persons having a kin relation, which can significantly decrease the performance. To address this problem...... the feature distance between face image pairs with kinship and maximize the distance between non-kinship pairs. Based on the subtracted feature, the verification is realized through a simple Gaussian based distance comparison method. Experiments on two public databases show that the feature subtraction method...

  3. Suppression of DC term in Fresnel digital holography by sequence subtraction of holograms

    CERN Document Server

    Kang, Jong-Chol; Im, Song-Jin

    2016-01-01

    An experimental method for suppression of DC term in the reconstructed images from Fresnel digital holograms is presented. In this method, two holograms for the same object are captured sequentially and subtracted. Since these two holograms are captured at different moments, they are slightly different from each other for fluctuations of noises. The DC term is suppressed in the image reconstructed from the subtraction hologram, while the two virtual and real images are successfully reconstructed. This method can be potentially used for the improvement of image quality reconstructed from Fresnel digital holograms.

  4. Screening of genes related to ovarian development in the swimming crab, Portunus trituberculatus, by suppression subtractive hybridization.

    Science.gov (United States)

    Yu, Z B; Mu, C K; Song, W W; Li, R H; Chen, Y E; Wang, C L

    2015-12-29

    The swimming crab, Portunus trituberculatus, is an important marine animal and is widely cultured in China. In the present study, suppression subtractive hybridization was applied to identify the differentially expressed genes in the ovaries of mature and immature P. trituberculatus. One hundred and seventy six expressed sequence tag (ESTs) were identified, of which 100 were down-regulated, and 76 up-regulated. BLAST analysis identified 51 unigenes, of which 27 were down-regulated, and 24 up-regulated. Quantitative real-time reverse transcriptase polymerase chain reaction results indicated that the SSH technique is valuable in screening genes related to ovarian development. Genes identified in this study encoded proteins corresponding to a wide range of functions and included immune response protein, transcription initiation factor, metabolic proteins, chromosome, histone h3, ovarian development-related protein, and vitellogenin. In addition, 64 metabolic pathways were annotated in differentially expressed ESTs by using the Kyoto Encyclopedia of Genes and Genomes pathway. Four annotated pathways (oxidative phosphorylation, carbon metabolism, fatty acid degradation, and protein digestion and absorption) appeared to be involved in ovarian development. In ontology analysis, 5.83% of the cellular process genes in reverse subtraction cDNA library are involved in reproduction, and 5.88% involved in developmental process. In up-regulated genes, myosin II-expressed polehole-like protein; histone h3; ovigerous-hair stripping substance; peritrophin 48; and ovarian development-related protein appeared to be involved in ovarian development. Identification of differentially expressed genes in the mature and immature ovary of the swimming crab provides new insights for further studies on the mechanism underlying ovarian development in this species.

  5. [Examination of reducing misregistration for lower tube voltage of the mask image in CT angiography using subtraction method].

    Science.gov (United States)

    Nakatani, Kasumi; Fukunishi, Yasunobu

    2015-05-01

    Computed tomographic angiography (CTA) has been used recently for the evaluation of intracerebral aneurysms, but it is difficult to use this technique to visualize aneurysms near the base of the skull because of the presence of bone. So, subtracted CTA has been used to separate vessels from bony structures. However, we see some misregistration when using subtraction method because of the patient moving, the disaccord of the X-ray tube orbit between the mask image and the live image, the expanding focus, and the bed bending. So, attentioning the difference of bone CT number in any tube voltages, we examined to make the image containing less misregistration by changing the tube voltage of mask image. Making a sham blood vessel, we examined the bone misregistration, the blood vessel volume, and the smoothness when changing the tube voltages of mask images. Comparing with 120 kV, as the tube voltage of the mask image was 80 kV, the bone misregistration decreased significantly, however the blood vessel volume decreased. As for the tube voltage of 100 kV, the bone misregistration decreased significantly, and the blood vessel volume and the smoothness were not significantly different so we could get coordinative image of 120 kV. When the tube voltage of the mask image becomes lower than that of the live image and the effective energy becomes different, the effect of misregistration is less. This method deals with changing the tube voltage only. So, it may be easy to make volume rendering (VR) image and this method may be used in every facility.

  6. Metal artifact reduction method using metal streaks image subtraction

    Energy Technology Data Exchange (ETDEWEB)

    Pua, Rizza D.; Cho, Seung Ryong [Dept. of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)

    2014-04-15

    Many studies have been dedicated for metal artifact reduction (MAR); however, the methods are successful to varying degrees depending on situations. Sinogram in-painting, filtering, iterative method are some of the major categories of MAR. Each has its own merits and weaknesses. A combination of these methods or hybrid methods have also been developed to make use of the different benefits of two techniques and minimize the unfavorable results. Our method focuses on the in-paitning approach and a hybrid MAR described by Xia et al. Although in-painting scheme is an effective technique in reducing the primary metal artifacts, a major drawback is the reintroduction of new artifacts that can be caused by an inaccurate interpolation process. Furthermore, combining the segmented metal image to the corrected nonmetal image in the final step of a conventional inpainting approach causes an issue of incorrect metal pixel values. Our proposed method begins with a sinogram in-painting approach and ends with an image-based metal artifact reduction scheme. This work provides a simple, yet effective solution for reducing metal artifacts and acquiring the original metal pixel information. The proposed method demonstrated its effectiveness in a simulation setting. The proposed method showed image quality that is comparable to the standard MAR; however, quantitatively more accurate than the standard MAR.

  7. Effect of color coding and subtraction on the accuracy of contrast echocardiography

    Science.gov (United States)

    Pasquet, A.; Greenberg, N.; Brunken, R.; Thomas, J. D.; Marwick, T. H.

    1999-01-01

    BACKGROUND: Contrast echocardiography may be used to assess myocardial perfusion. However, gray scale assessment of myocardial contrast echocardiography (MCE) is difficult because of variations in regional backscatter intensity, difficulties in distinguishing varying shades of gray, and artifacts or attenuation. We sought to determine whether the assessment of rest myocardial perfusion by MCE could be improved with subtraction and color coding. METHODS AND RESULTS: MCE was performed in 31 patients with previous myocardial infarction with a 2nd generation agent (NC100100, Nycomed AS), using harmonic triggered or continuous imaging and gain settings were kept constant throughout the study. Digitized images were post processed by subtraction of baseline from contrast data and colorized to reflect the intensity of myocardial contrast. Gray scale MCE alone, MCE images combined with baseline and subtracted colorized images were scored independently using a 16 segment model. The presence and severity of myocardial contrast abnormalities were compared with perfusion defined by rest MIBI-SPECT. Segments that were not visualized by continuous (17%) or triggered imaging (14%) after color processing were excluded from further analysis. The specificity of gray scale MCE alone (56%) or MCE combined with baseline 2D (47%) was significantly enhanced by subtraction and color coding (76%, pcolorized images (59%) was also significantly greater than gray scale MCE (43% and 29%, pcolor coding significantly improves the accuracy and specificity of MCE for detection of perfusion defects.

  8. COMPARISON OF GEOMETRIC PRECISION OF PLASTIC COMPONENTS MADE BY SUBTRACTIVE AND ADDITIVE METHODS

    Directory of Open Access Journals (Sweden)

    Paweł Fudali

    2013-09-01

    Full Text Available The paper presents information on manufacturing processes of plastic components. Basic subtractive and additive methods are described. There were also manufactured elements of fan housing by using this two types of methods. Then, the elements were measured using a touch probe. The obtained results were analyzed, on which a comparison of components’ geometric accuracy was performed.

  9. PHOTON-SUBTRACTED (-ADDED) THERMO VACUUM STATE AND THEIR APPLICATION IN JACOBI POLYNOMIALS

    Institute of Scientific and Technical Information of China (English)

    DA Cheng; FAN Hong-yi

    2015-01-01

    We construct photon-subtracted (-added) thermo vacuum state by normalizing them. As their application we derive some new generating function formulas of Jacobi polynomials, which may be applied to study other problems in quantum mechanics. This will also stimulate the research of mathematical physics in the future.

  10. Pre-operative sestamibi-technetium subtraction scintigraphy in primary hyperparathyroidism: Experience with 156 consecutive patients

    Energy Technology Data Exchange (ETDEWEB)

    Jones, J. Mark; Russell, Colin F.J.; Ferguson, W. Rodney; Laird, James D

    2001-07-01

    AIM: The aim of this study was to assess the usefulness of pre-operative sestamibi-technetium subtraction scintigraphy in a large cohort of patients with primary hyperparathyroidism (HPT). MATERIALS AND METHODS: A group of 156 consecutive patients with biochemically proven HPT underwent sestamibi-technetium subtraction scintigraphy before cervical exploration. Images were interpreted and reported prospectively and influenced the extent of surgical exploration. The intraoperative findings were compared retrospectively with the pre-operative scintigram reports in 154 individuals with technically satisfactory scintigrams. RESULTS: Of the 154 patients with satisfactory scintigrams, 122 (78.2%) demonstrated a single focus of activity following subtraction, 31 (19.9%) had negative findings and the remaining scintigram showed four foci of activity. At operation 138 (89.6%) solitary adenomas were removed, 13 patients (8.4%) had multi-gland disease and in three individuals (2.0%) no abnormal parathyroid tissue was found. The pre-operative scintigram accurately localized 91 of 98 (92.9%) solitary tumours weighing > 500 mg but only 18 of 35 (51.4%) adenomas weighing < 500 mg, (P < 0.0001). Overall sensitivity of sestamibi-technetium scintigraphy for localizing single parathyroid adenomas was 83.7%. CONCLUSION: Sestamibi-technetium subtraction scintigraphy will accurately localize a high proportion of solitary parathyroid adenomas but its usefulness is diminished by its inability to consistently identify smaller tumours. Jones, J.M. et al. (2001)

  11. Combining Suppression Subtractive Hybridization and Microarrays To Map the Intraspecies Phylogeny of Flavobacterium psychrophilum

    OpenAIRE

    Soule, Marilyn; Cain, Kenneth; Lafrentz, Stacey; Douglas R. Call

    2005-01-01

    Reciprocal subtractive libraries were prepared for two strains of Flavobacterium psychrophilum, one virulent and the other avirulent in a trout challenge model. Unique clones were sequenced and their distribution assessed among 34 strains. The analysis showed that F. psychrophilum is composed of two genetic lineages, possibly reflecting host specificity.

  12. Identification of a pheA gene associated with Streptococcus mitis by using suppression subtractive hybridization.

    Science.gov (United States)

    Park, Hee Kuk; Dang, Hien Thanh; Myung, Soon Chul; Kim, Wonyong

    2012-04-01

    We performed suppression subtractive hybridization to identify genomic differences between Streptococcus mitis and Streptococcus pneumoniae. Based on the pheA gene, a primer set specific to S. mitis detection was found in 18 out of 103 S. mitis-specific clones. Our findings would be useful for discrimination of S. mitis from other closely related cocci in the oral environment.

  13. Identification by Suppression Subtractive Hybridization of Frankia Genes Induced under Nitrogen-Fixing Conditions▿ †

    OpenAIRE

    Yamaura, Masatoshi; UCHIUMI, Toshiki; Higashi, Shiro; Abe, Mikiko; Kucho, Ken-ichi

    2010-01-01

    Frankia is an actinobacterium that fixes nitrogen under both symbiotic and free-living conditions. We identified genes upregulated in free-living nitrogen-fixing cells by using suppression subtractive hybridization. They included genes with predicted functions related to nitrogen fixation, as well as with unknown function. Their upregulation was a novel finding in Frankia.

  14. Identification of a pheA Gene Associated with Streptococcus mitis by Using Suppression Subtractive Hybridization

    OpenAIRE

    Park, Hee Kuk; Dang, Hien Thanh; Myung, Soon Chul; Kim, Wonyong

    2012-01-01

    We performed suppression subtractive hybridization to identify genomic differences between Streptococcus mitis and Streptococcus pneumoniae. Based on the pheA gene, a primer set specific to S. mitis detection was found in 18 out of 103 S. mitis-specific clones. Our findings would be useful for discrimination of S. mitis from other closely related cocci in the oral environment.

  15. Genetic Differences between Two Strains of Xylella fastidiosa Revealed by Suppression Subtractive Hybridization†

    OpenAIRE

    Harakava,Ricardo; Gabriel, Dean W.

    2003-01-01

    Suppression subtractive hybridization was used to rapidly identify 18 gene differences between a citrus variegated chlorosis (CVC) strain and a Pierce's disease of grape (PD) strain of Xylella fastidiosa. The results were validated as being highly representative of actual differences by comparison of the completely sequenced genome of a CVC strain with that of a PD strain.

  16. Developing Prospective Teachers' Understanding of Addition and Subtraction with Whole Numbers

    Science.gov (United States)

    Roy, George J.

    2014-01-01

    This study was situated in a semester-long classroom teaching experiment examining prospective teachers' understanding of number concepts and operations. The purpose of this paper is to describe the learning goals, tasks, and tools used to cultivate prospective teachers' understanding of addition and subtraction with whole numbers.…

  17. Helping Students to Connect Subtraction Strategies Improves Mathematical Reasoning for Students and Teachers

    Science.gov (United States)

    Sci, Eve

    2011-01-01

    After administering an end of unit assessment written by the school's math program, teachers of three second grade classes in a New York City school noticed a majority of the students had not demonstrated mastery of subtracting two, two-digit numbers. The teachers worked with the school's math coach to implement an instructional unit that required…

  18. Advanced nanopattern formation by a subtractive self-organization process with focused ion beams

    Energy Technology Data Exchange (ETDEWEB)

    Lugstein, A. [Technical University Vienna, Floragasse 7, 1040 Vienna (Austria)]. E-mail: alois.lugstein@tuwien.ac.at; Basner, B. [Technical University Vienna, Floragasse 7, 1040 Vienna (Austria); Brezna, W. [Technical University Vienna, Floragasse 7, 1040 Vienna (Austria); Weil, M. [Technical University Vienna, Floragasse 7, 1040 Vienna (Austria); Golka, S. [Technical University Vienna, Floragasse 7, 1040 Vienna (Austria); Bertagnolli, E. [Technical University Vienna, Floragasse 7, 1040 Vienna (Austria)

    2006-01-15

    We have studied the evolution of the GaAs, InAs and GaSb surfaces due to FIB exposure. In contrast to conventional bottom up or top down processes the observed nanopattern formation is discussed, based on a subtractive self-organization process relying on material decomposition induced by FIB exposure.

  19. [Construction and analysis of subtractive cDNA library associated with multidrug resistance of acute leukemia].

    Science.gov (United States)

    Ji, Lei; Zhang, Wang-Gang; Liu, Jie; Liu, Xin-Ping; Yao, Li-Bo

    2004-08-01

    The study was aimed to construct subtractive cDNA library associated with multidrug resistance (MDR) of acute leukemia for screening genes related to MDR in leukemia. The improved PCR-based subtractive hybridization was performed to clone differential genes between HL-60/VCR and HL-60 cell line. The mRNA of HL-60/VCR and HL-60 cell line were isolated. Then the mRNA of HL-60/VCR group was reversely transcribed into cDNA by Cap-Finder method, and the mRNA of HL-60 was reversely transcribed into cDNA by ordinary method to be marked by biotin for the hybridization next with HL-60/VCR cDNA. After hybridizing, filtrating through the sephacryl S-400 column, absorbing by the magnetic beads, and amplifying by PCR method, the fragments were cloned by T-A method and the cDNA library was constructed. Then the quality of cDNA library was identified by dot-blotting hybridization method. The results showed that after constriction, the library demonstrated its good quality. There was a high proportion of large fragments in this library. From small amount of samples a large amount of candidate fragments could be screened rapidly at once by dot-blotting hybridization. It is concluded that a differentially-expressed subtractive cDNA library in MDR of leukemia with high quality and larger fragments can be efficiently constructed by improving subtractive hybridization and selective PCR method.

  20. Isolation of carrot Argonaute1 from subtractive somatic embryogenesis cDNA library.

    Science.gov (United States)

    Takahata, Kiminori

    2008-03-01

    Carrot Argonaute1 (C-Ago1) was isolated from a subtractive cDNA library to obtain somatic embryogenesis related genes. C-Ago1 has three conserved domains, which are found in all other Argonautes. C-Ago1 has specific expression during somatic embryogenesis, which indicates that microRNA gene expression controlling system is required for somatic embryogenesis.

  1. [X-ray semiotics of sialolithiasis in functional digital subtraction sialography].

    Science.gov (United States)

    Iudin, L A; Kondrashin, S A; Afanas'ev, V V; Shchipskiĭ, A V

    1995-01-01

    Twenty-seven patients with sialolithiasis were examined using functional subtraction sialography developed by the authors. Differential diagnostic signs characterizing the degree of involvement of the salivary gland were defined. High efficacy of the method helps correctly plan the treatment strategy.

  2. Dissociation of Subtraction and Multiplication in the Right Parietal Cortex: Evidence from Intraoperative Cortical Electrostimulation

    Science.gov (United States)

    Yu, Xiaodan; Chen, Chuansheng; Pu, Song; Wu, Chenxing; Li, Yongnian; Jiang, Tao; Zhou, Xinlin

    2011-01-01

    Previous research has consistently shown that the left parietal cortex is critical for numerical processing, but the role of the right parietal lobe has been much less clear. This study used the intraoperative cortical electrical stimulation approach to investigate neural dissociation in the right parietal cortex for subtraction and…

  3. Digital subtraction cystography for detection of communicating holes of spinal extradural arachnoid cysts

    Energy Technology Data Exchange (ETDEWEB)

    Gu, Kyo Won; Kwon, Jong Won; Kim, Eun Sang [Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of)

    2016-02-15

    The purpose of this study was to demonstrate the usefulness of digital subtraction cystography to identify communicating holes between a spinal extradural arachnoid cyst (SEAC) and the subarachnoid space prior to cyst removal and hole closure. Six patients with SEAC were enrolled in this retrospective study. Digital subtraction cystography and subsequent CT myelography were performed for every patient. The presence and location of the communicating holes on cystography were documented. We evaluated the MRI characteristics of the cysts, including location, size, and associated spinal cord compression; furthermore, we reviewed cystographic images, CT myelograms, procedural reports, and medical records for analysis. If surgery was performed after cystography, intraoperative findings were compared with preoperative cystography. The location of the communicating hole between the arachnoid cyst and the subarachnoid space was identified by digital subtraction cystography in all cases (n = 6). Surgical resection of SEAC was performed in 4 patients, and intraoperative location of the communicating hole exactly corresponded to the preoperative identification. Fluoroscopic-guided cystography for SEAC accurately demonstrates the presence and location of dural defects. Preoperative digital subtraction cystography is useful for detection of a communicating hole between a cyst and the subarachnoid space.

  4. Generating Scenarios of Addition and Subtraction: A Study of Japanese University Students

    Science.gov (United States)

    Kinda, Shigehiro

    2013-01-01

    Students are presented with problems involving three scenario types of addition and subtraction in elementary mathematics: one dynamic ("Change") and two static ("Combine, Compare"). Previous studies have indicated that the dynamic type is easier for school children, whereas the static types are more difficult and comprehended only gradually…

  5. Issues relating to the subtraction phase in EOG artefact correction of the EEG.

    Science.gov (United States)

    Croft, Rodney J; Barry, Robert J

    2002-06-01

    An important method for removing the effect of ocular artefact from the EEG is 'EOG correction'. This method estimates the proportion of ocular artefact that is in the EEG, and removes it by subtraction. To date, EOG correction research has focused on problems relating to the estimation of the correction coefficients. Using both mathematical rationale and empirical data, this paper addresses issues relating to the subtraction phase, such as the magnitude of error that can be expected due to EOG correction. Using ERP methodology, principal component and regression analyses, it is shown that the N1P2 complex propagates forward to the horizontal and radial (but not vertical) electrooculograms (EOG), and it is shown mathematically that this will result in EOG-correction error. Assuming an accurate estimate of ocular contamination of the EEG, maximal subtraction-phase error of the N1P2 complex was found to be a prefrontal attenuation of 15-22%, decreasing to central and occipital enhancements of 3-4% and 13-14%, respectively. The magnitude of this subtraction-phase error is compared to between-subject ERP variability and to error associated with EOG rejection (omitting data contaminated by ocular artefact). It is argued that such EOG correction error is small relative to both artefact rejection procedures and to normal variability found in ERP studies, and that it is less pernicious than artefact rejection procedures.

  6. Low-cost addition-subtraction sequences for the final exponentiation computation in pairings

    DEFF Research Database (Denmark)

    Guzmán-Trampe, Juan E; Cruz-Cortéz, Nareli; Dominguez Perez, Luis

    2014-01-01

    In this paper, we address the problem of finding low cost addition–subtraction sequences for situations where a doubling step is significantly cheaper than a non-doubling one. One application of this setting appears in the computation of the final exponentiation step of the reduced Tate pairing d...

  7. Strategies for Solving Simple Subtractions as Reflected by Children's Verbal Reports.

    Science.gov (United States)

    Svenson, Ola; Hedenborg, Maj-Lene

    1980-01-01

    Children, 9-11 years old, solved subtraction problems in the form of M-N=..., then gave a verbal report on the thought processes used, analysis of which utilized a model based on analyses of reaction times, and resulted in a more detailed process model. (AN)

  8. Proximal caries detection using digital subtraction radiography in the artificial caries activity model

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jong Hoon; Lee, Gi Ja; Choi, Sam Jin; Park, Young Ho; Kim, Kyung Soo; Jin, Hyun Seok; Hong, Kyung Won; Oh, Berm Seok; Park, Hun Kuk [Department of Biomedical Engineering, School of Medicine, Kyung Hee University, Seoul (Korea, Republic of); Choi, Yong Suk; Hwang, Eui Hwan [Department of Oral and Maxillofacial Radiology, Institute of Oral Biology, School of Dentistry, Kyung Hee University, Seoul (Korea, Republic of)

    2009-03-15

    The purpose of the experiment was to evaluating the diagnostic ability of dental caries detection using digital subtraction in the artificial caries activity model. Digital radiographs of five teeth with 8 proximal surfaces were obtained by CCD sensor (Kodak RVG 6100 using a size no.2). The digital radiographic images and subtraction images from artificial proximal caries were examined and interpreted. In this study, we proposed novel caries detection method which could diagnose the dental proximal caries from single digital radiographic image. In artificial caries activity model, the range of lesional depth was 572-1,374 {mu}m and the range of lesional area was 36.95-138.52 mm{sup 2}. The lesional depth and the area were significantly increased with demineralization time (p<0.001). Furthermore, the proximal caries detection using digital subtraction radiography showed high detection rate compared to the proximal caries examination using simple digital radiograph. The results demonstrated that the digital subtraction radiography from single radiographic image of artificial caries was highly efficient in the detection of dental caries compared to the data from simple digital radiograph.

  9. Heritage Language Learners in Mixed Spanish Classes: Subtractive Practices and Perceptions of High School Spanish Teachers

    Science.gov (United States)

    Randolph, Linwood J., Jr.

    2017-01-01

    This qualitative study investigated the language ideologies and instructional practices of an entire Spanish language faculty at a high school in a new gateway state for immigration. The study examined additive and subtractive practices of teachers as they strived to teach Spanish to heritage language learners (HLLs) enrolled in mixed…

  10. "It is Possible to Die Before Being Born". Negative Integers Subtraction: A Case Study

    Science.gov (United States)

    Gallardo, Aurora

    2003-01-01

    A Case Study is presented in this article, where there is a contradiction between pre-algebraic language semantic and syntax used to solve word problems through a negative integers subtraction. Appendix includes answer key. (Contains 1 figure.) [For complete proceedings, see ED500859.

  11. [The improved design of table operating box of digital subtraction angiography device].

    Science.gov (United States)

    Qi, Xianying; Zhang, Minghai; Han, Fengtan; Tang, Feng; He, Lemin

    2009-12-01

    In this paper are analyzed the disadvantages of CGO-3000 digital subtraction angiography table Operating Box. The authors put forward a communication control scheme between single-chip microcomputer(SCM) and programmable logic controller(PLC). The details of hardware and software of communication are given.

  12. Dissociation of Subtraction and Multiplication in the Right Parietal Cortex: Evidence from Intraoperative Cortical Electrostimulation

    Science.gov (United States)

    Yu, Xiaodan; Chen, Chuansheng; Pu, Song; Wu, Chenxing; Li, Yongnian; Jiang, Tao; Zhou, Xinlin

    2011-01-01

    Previous research has consistently shown that the left parietal cortex is critical for numerical processing, but the role of the right parietal lobe has been much less clear. This study used the intraoperative cortical electrical stimulation approach to investigate neural dissociation in the right parietal cortex for subtraction and…

  13. Considering ERP difference scores as individual difference measures: Issues with subtraction and alternative approaches.

    Science.gov (United States)

    Meyer, Alexandria; Lerner, Matthew D; De Los Reyes, Andres; Laird, Robert D; Hajcak, Greg

    2017-01-01

    There is growing interest in psychophysiological and neural correlates of psychopathology, personality, and other individual differences. Many studies correlate a criterion individual difference variable (e.g., anxiety) with a psychophysiological measurement derived by subtracting scores taken from two within-subject conditions. These subtraction-based difference scores are intended to increase specificity by isolating variability of interest. Using data on the error-related negativity (ERN) and correct response negativity (CRN) in relation to generalized anxiety disorder (GAD), we highlight several conceptual and practical issues with subtraction-based difference scores and propose alternative approaches based on regression. We show that ERN and CRN are highly correlated, and that the ΔERN (i.e., ERN - CRN) is correlated in opposite directions both with ERN and CRN. Bivariate analyses indicate that GAD is related to ΔERN and ERN, but not CRN. We first show that, by using residualized scores, GAD relates both to a larger ERN and smaller CRN. Moreover, by probing the interaction of ERN and CRN, we show that the relationship between GAD and ERN varies by CRN. These latter findings are not evident when using traditional subtraction-based difference scores. We then completed follow-up analyses that suggested that an increased P300 in anxious individuals gave rise to the apparent anxiety/CRN relationship observed. These findings have important conceptual implications for facilitating the interpretability of results from individual difference studies of psychophysiology.

  14. Application of DR Dual Energy Subtraction in Chest Trauma%DR双能量减影技术在胸部外伤中的应用

    Institute of Scientific and Technical Information of China (English)

    陈志辉; 田龙海

    2011-01-01

    [Objective] To investigate the value of dual energy subtraction technique for the diagnosis oftraumatic rib fracture. [Methods]Totally 92 patients with rib fractures were selected to receive DR dual energy subtraction examination of chest. A standard image, a soft tissue image and a bone tissue image were obtained from each patient. The display rate was compared between standard image and bone image for different segments of rib fraetures. [Results] A total of 224 rib fractures were found in 92 patients, and the display rate of bone tissue image was 98.2%which was significantly higher than that of standard image (88.4%) (P<0.05). [Conclusion] Dual energy subtraction technique can significantly improve the display rate of rib fracture, so it has significant value for the diagnosis of rib fracture.%[目的]探讨双能量减影技术在外伤性肋骨骨折中的诊断价值.[方法] 选择92例肋骨骨折患者行胸部DR双能量减影检查,每例患者分别获得一幅标准图像,一幅软组织图像,一幅骨组织图像,比较标准图像和骨组织图像对肋骨不同节段骨折的显示率.[结果]92 例患者共发现224 处肋骨骨折,骨组织图像显示率98.2%显著高于标准图像88.4%(P<0.05).[结论]双能量减影技术明显提高肋骨骨折的显示率,在肋骨骨折的诊断中有重要价值.

  15. Gender Differences in Elementary School Children's Strategy Use and Strategy Preferences on Multidigit Addition and Subtraction Story Problems

    Science.gov (United States)

    Edwards-Omolewa, Nicola D.

    2011-01-01

    Gender differences in the strategies elementary school children use to solve multidigit addition and subtraction story problems that require regrouping are investigated in two studies. Study 1 replicates the Fennema and colleagues (1998) study by reexamining previously published data on 72 children's addition and subtraction solution strategies.…

  16. Evaluation of carotid vessel wall enhancement with image subtraction after gadobenate dimeglumine-enhanced MR angiography

    Energy Technology Data Exchange (ETDEWEB)

    Sardanelli, Francesco [Department of Medical and Surgical Sciences, University of Milan School of Medicine, via Morandi 30, 20097 San Donato Milanese, Milan (Italy); Unit of Radiology, IRCCS Policlinico San Donato, via Morandi 30, 20097 San Donato Milanese, Milan (Italy)], E-mail: f.sardanelli@grupposandonato.it; Di Leo, Giovanni [Unit of Radiology, IRCCS Policlinico San Donato, via Morandi 30, 20097 San Donato Milanese, Milan (Italy)], E-mail: gianni.dileo77@virgilio.it; Aliprandi, Alberto [Unit of Radiology, IRCCS Policlinico San Donato, via Morandi 30, 20097 San Donato Milanese, Milan (Italy)], E-mail: a.aliprandi@grupposandonato.it; Flor, Nicola [Department of Diagnostic and Interventional Radiology, University of Milan School of Medicine, San Paolo Hospital, via di Rudini 8, 20142 Milan (Italy)], E-mail: flornic@hotmail.com; Papini, Giacomo D.E. [Unit of Radiology, IRCCS Policlinico San Donato, via Morandi 30, 20097 San Donato Milanese, Milan (Italy)], E-mail: giacomo.papini@fastwebnet.it; Roccatagliata, Luca [Unit of Radiology, IRCCS Policlinico San Donato, via Morandi 30, 20097 San Donato Milanese, Milan (Italy); Department of Neuroscience, Ophthalmology and Genetics, University of Genoa, via De Toni 5, 16132 Genoa (Italy)], E-mail: lroccatagliata@neurologia.unige.it; Cotticelli, Biagio [Unit of Radiology, IRCCS Policlinico San Donato, via Morandi 30, 20097 San Donato Milanese, Milan (Italy)], E-mail: neurobiagio@tiscali.it; Nano, Giovanni [Department of Medical and Surgical Sciences, University of Milan School of Medicine, via Morandi 30, 20097 San Donato Milanese, Milan (Italy); Unit of Vascular Surgery, IRCCS Policlinico San Donato, via Morandi 30, 20097 Milan (Italy)], E-mail: gianni.nano@libero.it; Cornalba, Gianpaolo [Department of Diagnostic and Interventional Radiology, University of Milan School of Medicine, San Paolo Hospital, via di Rudini 8, 20142 Milan (Italy)], E-mail: gianpaolo.cornalba@unimi.it

    2009-06-15

    Objectives: This study was aimed at testing the value of image subtraction for evaluating carotid vessel wall enhancement in contrast-enhanced MR angiography (MRA). Materials and methods: IRB approval was obtained. The scans of 81 consecutive patients who underwent carotid MRA with 0.1 mmol/kg of gadobenate dimeglumine were reviewed. Axial carotid 3D T1-weighted fast low-angle shot sequence before and 3 min after contrast injection were acquired and subtracted (enhanced minus unenhanced). Vessel wall enhancement was assigned a four-point score using native or subtracted images from 0 (no enhancement) to 3 (strong enhancement). Stenosis degree was graded according to NASCET. Results: With native images, vessel wall enhancement was detected in 20/81 patients (25%) and in 20/161 carotids (12%), and scored 2.0 {+-} 0.6 (mean {+-} standard deviation); with subtracted images, in 21/81 (26%) and 22/161 (14%), and scored 2.5 {+-} 0.6, respectively (P < 0.001, Sign test). The overall stenosis degree distribution was: mild, 41/161 (25%); moderate, 77/161 (48%); severe, 43/161 (27%). Carotids with moderate stenosis showed vessel wall enhancement with a frequency (17/77, 22%) significantly higher than that observed in carotids with mild stenosis (1/41, 2%) (P = 0.005, Fisher exact test) and higher, even though with borderline significance (P = 0.078, Fisher exact test), than that observed in carotids with severe stenosis (4/43, 9%). Conclusion: Roughly a quarter of patients undergoing carotid MRA showed vessel wall enhancement. Image subtraction improved vessel wall enhancement conspicuity. Vessel wall enhancement seems to be an event relatively independent from the degree of stenosis. Further studies are warranted to define the relation between vessel wall enhancement and histopathology, inflammatory status, and instability.

  17. Bone images from dual-energy subtraction chest radiography in the detection of rib fractures

    Energy Technology Data Exchange (ETDEWEB)

    Szucs-Farkas, Zsolt, E-mail: zsolt.szuecs@insel.ch [Department of Diagnostic, Interventional and Pediatric Radiology, University Hospital Bern, Freiburgstrasse 4, Bern CH-3010 (Switzerland); Lautenschlager, Katrin, E-mail: katrin@students.unibe.ch [Department of Diagnostic, Interventional and Pediatric Radiology, University Hospital Bern, Freiburgstrasse 4, Bern CH-3010 (Switzerland); Flach, Patricia M., E-mail: patricia.flach@irm.unibe.ch [Institute of Forensic Medicine, University of Bern, Freiburgstrasse 4, Bern CH-3010 (Switzerland); Ott, Daniel, E-mail: daniel.ott@insel.ch [Department of Diagnostic, Interventional and Pediatric Radiology, University Hospital Bern, Freiburgstrasse 4, Bern CH-3010 (Switzerland); Strautz, Tamara, E-mail: tamara.strautz@insel.ch [Department of Diagnostic, Interventional and Pediatric Radiology, University Hospital Bern, Freiburgstrasse 4, Bern CH-3010 (Switzerland); Vock, Peter, E-mail: peter.vock@insel.ch [Department of Diagnostic, Interventional and Pediatric Radiology, University Hospital Bern, Freiburgstrasse 4, Bern CH-3010 (Switzerland); Ruder, Thomas D., E-mail: thomas.ruder@irm.unibe.ch [Institute of Forensic Medicine, University of Bern, Freiburgstrasse 4, Bern CH-3010 (Switzerland)

    2011-08-15

    Objective: To assess the sensitivity and image quality of chest radiography (CXR) with or without dual-energy subtracted (ES) bone images in the detection of rib fractures. Materials and methods: In this retrospective study, 39 patients with 204 rib fractures and 24 subjects with no fractures were examined with a single exposure dual-energy subtraction digital radiography system. Three blinded readers first evaluated the non-subtracted posteroanterior and lateral chest radiographs alone, and 3 months later they evaluated the non-subtracted images together with the subtracted posteroanterior bone images. The locations of rib fractures were registered with confidence levels on a 3-grade scale. Image quality was rated on a 5-point scale. Marks by readers were compared with fracture localizations in CT as a standard of reference. Results: The sensivity for fracture detection using both methods was very similar (34.3% with standard CXR and 33.5% with ES-CXR, p = 0.92). At the patient level, both sensitivity (71.8%) and specificity (92.9%) with or without ES were identical. Diagnostic confidence was not significantly different (2.61 with CXR and 2.75 with ES-CXR, p = 0.063). Image quality with ES was rated higher than that on standard CXR (4.08 vs. 3.74, p < 0.001). Conclusions: Despite a better image quality, adding ES bone images to standard radiographs of the chest does not provide better sensitivity or improved diagnostic confidence in the detection of rib fractures.

  18. Computed tomography lung iodine contrast mapping by image registration and subtraction

    Science.gov (United States)

    Goatman, Keith; Plakas, Costas; Schuijf, Joanne; Beveridge, Erin; Prokop, Mathias

    2014-03-01

    Pulmonary embolism (PE) is a relatively common and potentially life threatening disease, affecting around 600,000 people annually in the United States alone. Prompt treatment using anticoagulants is effective and saves lives, but unnecessary treatment risks life threatening haemorrhage. The specificity of any diagnostic test for PE is therefore as important as its sensitivity. Computed tomography (CT) angiography is routinely used to diagnose PE. However, there are concerns it may over-report the condition. Additional information about the severity of an occlusion can be obtained from an iodine contrast map that represents tissue perfusion. Such maps tend to be derived from dual-energy CT acquisitions. However, they may also be calculated by subtracting pre- and post-contrast CT scans. Indeed, there are technical advantages to such a subtraction approach, including better contrast-to-noise ratio for the same radiation dose, and bone suppression. However, subtraction relies on accurate image registration. This paper presents a framework for the automatic alignment of pre- and post-contrast lung volumes prior to subtraction. The registration accuracy is evaluated for seven subjects for whom pre- and post-contrast helical CT scans were acquired using a Toshiba Aquilion ONE scanner. One hundred corresponding points were annotated on the pre- and post-contrast scans, distributed throughout the lung volume. Surface-to-surface error distances were also calculated from lung segmentations. Prior to registration the mean Euclidean landmark alignment error was 2.57mm (range 1.43-4.34 mm), and following registration the mean error was 0.54mm (range 0.44-0.64 mm). The mean surface error distance was 1.89mm before registration and 0.47mm after registration. There was a commensurate reduction in visual artefacts following registration. In conclusion, a framework for pre- and post-contrast lung registration has been developed that is sufficiently accurate for lung subtraction

  19. Accuracy of Digital Subtraction Radiography in the Detection of Vertical Root Fractures.

    Science.gov (United States)

    Queiroz, Polyane Mazucatto; Nascimento, Helena Aguiar Ribeiro; da Paz, Thais Diniz Jacome; Anacleto, Felipe Nogueira; Freitas, Deborah Queiroz

    2016-06-01

    The objective of this study was to evaluate the accuracy of digital subtraction radiography in the diagnosis of vertical root fractures (VRFs). Twenty decoronated uniradicular human teeth were placed in the alveoli of a dry mandible and radiographed twice, first without (unfilled roots) and then with (filled roots) a gutta-percha cone placed into the root canal. Roots were then removed from the dry mandible, and vertical fractures were created with the aid of a universal testing machine. The fractured roots were repositioned in the mandibular alveoli and again radiographed twice. Radiographic images were subtracted by using the Regeemy software in 3 test situations: group 1, initial radiographic images of unfilled roots and images of fractured or non-fractured unfilled roots; group 2, initial radiographic images of unfilled roots and images of fractured or non-fractured filled roots; and group 3, initial radiographic images of filled roots and images of fractured or non-fractured filled roots. Three examiners evaluated all the original digital radiographs, as well as the subtracted images, for the presence or absence of VRFs. Numerical data were subject to statistical analysis with the use of receiver operator characteristic (ROC) curves. The areas under the ROC curve for groups 1, 2, and 3 were 0.86, 0.73, and 0.66, respectively. For the original digital radiographs, areas under the ROC curve were 0.80 (without gutta-percha) and 0.73 (with gutta-percha). No statistically significant differences were found between subtracted and original images. Digital subtraction radiography could be considered as an alternative tool for the investigation of VRFs because of its comparable diagnostic accuracy to existing methods. Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  20. Identifying genes related to choriogenesis in insect panoistic ovaries by Suppression Subtractive Hybridization

    Directory of Open Access Journals (Sweden)

    Bellés Xavier

    2009-04-01

    Full Text Available Abstract Background Insect ovarioles are classified into two categories: panoistic and meroistic, the later having apparently evolved from an ancestral panoistic type. Molecular data on oogenesis is practically restricted to meroistic ovaries. If we aim at studying the evolutionary transition from panoistic to meroistic, data on panoistic ovaries should be gathered. To this end, we planned the construction of a Suppression Subtractive Hybridization (SSH library to identify genes involved in panoistic choriogenesis, using the cockroach Blattella germanica as model. Results We constructed a post-vitellogenic ovary library by SSH to isolate genes involved in choriogenesis in B. germanica. The tester library was prepared with an ovary pool from 6- to 7-day-old females, whereas the driver library was prepared with an ovary pool from 3- to 4-day-old females. From the SSH library, we obtained 258 high quality sequences which clustered into 34 unique sequences grouped in 19 contigs and 15 singlets. The sequences were compared against non-redundant NCBI databases using BLAST. We found that 44% of the unique sequences had homologous sequences in known genes of other organisms, whereas 56% had no significant similarity to any of the databases entries. A Gene Ontology analysis was carried out, classifying the 34 sequences into different functional categories. Seven of these gene sequences, representative of different categories and processes, were chosen to perform expression studies during the first gonadotrophic cycle by real-time PCR. Results showed that they were mainly expressed during post-vitellogenesis, which validates the SSH technique. In two of them corresponding to novel genes, we demonstrated that they are specifically expressed in the cytoplasm of follicular cells in basal oocytes at the time of choriogenesis. Conclusion The SSH approach has proven to be useful in identifying ovarian genes expressed after vitellogenesis in B. germanica. For

  1. A novel approach to background subtraction in contrast-enhanced dual-energy digital mammography with commercially available mammography devices: Polychromaticity correction.

    Science.gov (United States)

    Contillo, Adriano; Di Domenico, Giovanni; Cardarelli, Paolo; Gambaccini, Mauro; Taibi, Angelo

    2015-11-01

    Contrast-enhanced digital mammography is an image subtraction technique that is able to improve the detectability of lesions in dense breasts. One of the main sources of error, when the technique is performed by means of commercial mammography devices, is represented by the intrinsic polychromaticity of the x-ray beams. The aim of the work is to propose an iterative procedure, which only assumes the knowledge of a small set of universal quantities, to take into account the polychromaticity and correct the subtraction results accordingly. In order to verify the procedure, it has been applied to an analytical simulation of a target containing a contrast medium and to actual radiographs of a breast phantom containing cavities filled with a solution of the same medium. The reconstructed densities of contrast medium were compared, showing very good agreement between the theoretical predictions and the experimental results already after the first iteration. Furthermore, the convergence of the iterative procedure was studied, showing that only a small number of iterations is necessary to reach limiting values. The proposed procedure represents an efficient solution to the polychromaticity issue, qualifying therefore as a viable alternative to inverse-map functions.

  2. A novel approach to background subtraction in contrast-enhanced dual-energy digital mammography with commercially available mammography devices: Polychromaticity correction

    Energy Technology Data Exchange (ETDEWEB)

    Contillo, Adriano, E-mail: contillo@fe.infn.it; Di Domenico, Giovanni; Cardarelli, Paolo; Gambaccini, Mauro; Taibi, Angelo [Dipartimento di Fisica e Scienze della Terra, Università degli Studi di Ferrara, Via Saragat 1, Ferrara I-44122 (Italy)

    2015-11-15

    Purpose: Contrast-enhanced digital mammography is an image subtraction technique that is able to improve the detectability of lesions in dense breasts. One of the main sources of error, when the technique is performed by means of commercial mammography devices, is represented by the intrinsic polychromaticity of the x-ray beams. The aim of the work is to propose an iterative procedure, which only assumes the knowledge of a small set of universal quantities, to take into account the polychromaticity and correct the subtraction results accordingly. Methods: In order to verify the procedure, it has been applied to an analytical simulation of a target containing a contrast medium and to actual radiographs of a breast phantom containing cavities filled with a solution of the same medium. Results: The reconstructed densities of contrast medium were compared, showing very good agreement between the theoretical predictions and the experimental results already after the first iteration. Furthermore, the convergence of the iterative procedure was studied, showing that only a small number of iterations is necessary to reach limiting values. Conclusions: The proposed procedure represents an efficient solution to the polychromaticity issue, qualifying therefore as a viable alternative to inverse-map functions.

  3. Screening and identification of differentially expressed transcripts in circulating cells of prostate cancer patients using suppression subtractive hybridization

    Directory of Open Access Journals (Sweden)

    Manatt C Scott

    2005-08-01

    Full Text Available Abstract Background Tumor metastasis and changes in host immunosurveillance are important components in cancer development. Tumor cell invasion into the bloodstream is an essential step for systemic metastasis. Currently, the detection of tumor cells in the circulation is mainly dependent upon the utilization of known epithelial cell markers. However, expression of these molecules is not limited to cancer patients; healthy people also have a small number of epithelial cells in their circulation. Utilizing these markers to detect circulating tumor cells (CTCs cannot adequately explain the mechanisms of tumor cell survival or their development of metastatic potential in peripheral blood. The immune system can also evolve along with the cancer, actually promoting or selecting the outgrowth of tumor variants. Unfortunately, both metastasis and immunosurveillance remain mysterious and are debatable because we have yet to define the molecules that participate in these processes. We are interested in identifying the existence of expressed genes, or mRNA species, that are specifically associated with circulating cells of cancer-bearing patients using prostate cancer (PCa as a model. Results We established two comprehensive subtracted cDNA libraries using a molecular technique called suppression subtractive hybridization. This technique selectively amplifies transcripts that are specifically expressed in circulating cells of either PCa patients or healthy men. Following sequencing reaction, we showed that 17 out of 23 (73.9% sequenced clones did not match any mRNAs in the GenBank database. This result suggests that genes associated with alterations in circulating cells of cancer-bearing patients are largely unknown. Semi-quantitative RT-PCR confirmed that two genes are up-regulated in circulating cells of PCa patients, whereas another two genes are down-regulated in the same patients. Conclusion The comprehensive gene expression analysis is capable of

  4. Research of improved spectral subtraction algorithm utilizing Turbo iteration%Turbo迭代下的改进谱减法研究

    Institute of Scientific and Technical Information of China (English)

    查诚; 杨平; 潘平

    2011-01-01

    自迭代式的谱减法虽然能有效提高去噪度,但是随着迭代次数的增加会造成语音畸变.结合Turbo迭代原理,在噪声子空间引入小波包多阈值去噪对迭代谱减法进行改进.将谱减法和小波包多阈值去噪根据Turbo原理结合起来,两个分量滤波算法各自工作在信号子空间和噪声予空间提取语音信号,并在每次迭代时将各自输出作为另一分量滤波算法的先验信息.仿真实验表明:该算法在10次Turbo选代处理后收敛,并在低信噪比下能较好地去噪和降低语音失真度.%Although self-iterative algorithm of Spectral Subtraction(SS) can improve signal-noise ratio, the level of speech distortion increases with the number of iterations,This paper proposes a new reinforced spectral subtraction algorithm that ap plies wavelet packet multi'thresholds de-noising in noisy subspace of noisy speech space based on Turbo iterative principle. The Turbo iterative processing is a technique in which self-iterative spectral subtraction is combined with wavelet packet multi-thresholds de-noising,Both component filters work cycled in signal subspace and noisy space respectively to extract speech information, each one takes some feedback information from the other filter as a priori condition.The simulation re sults show that this new algorithm converges within 10 iterations, and it achieves much better performance for the balance of noise reduction and speech distortion.

  5. Research of speech denoising algorithm based on spectrum subtraction%基于频谱减法的语音去噪算法研究

    Institute of Scientific and Technical Information of China (English)

    邓利娜; 黄晓革

    2011-01-01

    语音增强技术是音频信号处理中的重要部分,频谱减法是目前在语音增强技术中最常用的方法之一.针对传统频谱减法会产生音乐噪声并无法消除音乐噪声的不足之处及高频噪声干扰比较严重的情况下频谱减法效果差的情况,采用了在频谱减法之后进行LMS滤波以降低音乐噪声对语音质量的影响和低通滤波以滤除脉冲干扰.根据仿真结果表明,改进扩展频谱减法能够有效降低音乐噪声和尖锐的高频兹兹声,从而提高信噪比,达到语音增强的目的.%The speech enhancement technique is an important part of audio signal processing. Presently, spectral subtraction algorithm is very popular in this field. However, spectral subtraction algorithm usually adds “music noise" to the signal.Aiming at reducing annoying musical noise, in this paper, spectral subtraction algorithm combined with LMS filter and low pass filter is proposed, Simulation on computer shows that the new method is more effective in improving SNR and elimination musical noise and frequency noise.

  6. Arithmetic computation using self-assembly of DNA tiles:subtraction and division

    Institute of Scientific and Technical Information of China (English)

    Xuncai Zhang; Yanfeng Wang; Zhihua Chen; Jin Xu; Guangzhao Cui

    2009-01-01

    Recently,experiments have demonstrated that simple binary arithmetic and logical operations can be computed by the process of selfassembly of DNA tiles.In this paper,we show how the tile assembly process can be used for subtraction and division.In order to achieve this aim,four systems,including the comparator system,the duplicator system,the subtraction system,and the division system,are proposed to compute the difference and quotient of two input numbers using the tile assembly model.This work indicates that these systems can be carried out in polynomial time with optimal O(1)distinct tile types in parallel and at very low cost.Furthermore,we provide a scheme to factor the product of two prime numbers,and it is a breakthrough in basic biological operations using a molecular computer by self-assembly.

  7. Isolation and identification of genes expressed differentially in rice inflorescence meristem with suppression subtractive hybridization

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A subtracted cDNA library of rice (Oryza sativa L.) inflorescence meristem (IM) was constructed using the sup-pression subtractive hybridization (SSH) method. The cDNAs of the rice shoot apical meristem (SAM) were used as "driver" and inflorescence meristem (IM) as "tester" in the experiment, respectively. Forty of 250 randomly chosen cDNA clones were identified by differential screening, which were IM-specific or IM-highly expressed. Most of the rice IM cDNAs cloned by SSH appear to represent rare transcripts, 40% of which were derived from truly differentially ex-pressed genes. Of all the forty sequenced cDNA inserts, eleven contain the regions with 60%-90% identity to their homolog in GenBank, eighteen are expected to be new genes, only two correspond to published rice genes.

  8. Designing novel reversible BCD adder and parallel adder/subtraction using new reversible logic gates

    Science.gov (United States)

    Zhou, Rigui; Zhang, Manqun; Wu, Qian; Shi, Yang

    2012-10-01

    Reversible logic has received much attention in recent years when calculation with minimum energy consumption is considered. Especially, interest is sparked in reversible logic by its applications in some technologies, such as quantum computing, low-power CMOS design, optical information processing and nanotechnology. This article proposes two new reversible logic gates, ZRQ and NC. The first gate ZRQ not only implements all Boolean functions but also can be used to design optimised adder/subtraction architectures. One of the prominent functionalities of the proposed ZRQ gate is that it can work by itself as a reversible full adder/subtraction unit. The second gate NC can complete overflow detection logic of Binary Coded Decimal (BCD) adder. This article proposes two approaches to design novel reversible BCD adder using new reversible gates. A comparative result which is presented shows that the proposed designs are more optimised in terms of number of gates, garbage outputs, quantum costs and unit delays than the existing designs.

  9. Limits on Foreground Subtraction from Chromatic Beam Effects in Global Redshifted 21 cm Measurements

    CERN Document Server

    Mozdzen, Thomas J; Monsalve, Raul A; Rogers, Alan E E

    2015-01-01

    Foreground subtraction in global redshifted 21 cm measurements is limited by frequency-dependent (chromatic) structure in antenna beam patterns. Chromatic beams couple angular structures in Galactic foreground emission to spectral structures that may not be removed by smooth functional forms. We report results for simulations based on two dipole antennas used by the Experiment to Detect the Global EoR Signature (EDGES). The residual levels in simulated foreground-subtracted spectra are found to differ substantially between the two antennas, suggesting that antenna design must be carefully considered. Residuals are also highly dependent on the right ascension and declination of the antenna pointing, with RMS values differing by as much as a factor of 20 across pointings. For EDGES and other ground-based experiments with zenith pointing antennas, right ascension and declination correspond directly to the local sidereal time and the latitude of the deployment site, hence chromatic beam effects should be taken in...

  10. Gravity-Gradient Subtraction in 3rd Generation Underground Gravitational-Wave Detectors in Homogeneous Media

    CERN Document Server

    Harms, Jan; Dorsher, Steven; Mandic, Vuk

    2009-01-01

    In this paper, we develop a new approach to gravity-gradient noise subtraction for underground gravitational-wave detectors in homogeneous rock. The method is based on spatial harmonic expansions of seismic fields. It is shown that gravity-gradient noise produced by seismic fields from distant sources, stationary or non-stationary, can be calculated from seismic data measured locally at the test mass. Furthermore, the formula is applied to seismic fields from stationary local sources. It is found that gravity gradients from these fields can be subtracted using local seismic measurements. The results are confirmed numerically with a finite-element simulation. A new seismic-array design is proposed that provides the additional information about the seismic field required to ensure applicability of the approach to realistic scenarios even with inhomogeneous rock and non-stationary local sources.

  11. Strategies for Human Tumor Virus Discoveries: from Microscopic Observation to Digital Transcriptome Subtraction

    Directory of Open Access Journals (Sweden)

    Ezra David Mirvish

    2016-05-01

    Full Text Available Over 20% of human cancers worldwide are associated with infectious agents, including viruses, bacteria, and parasites. Various methods have been used to identify human tumor viruses, including electron microscopic observations of viral particles, immunologic screening, cDNA library screening, nucleic acid hybridization, consensus PCR, viral DNA array chip, and representational difference analysis (RDA. With the Human Genome Project, a large amount of genetic information from humans and other organisms has accumulated over the last decade. Utilizing the available genetic databases, Patrick S. Moore, Yuan Chang, and colleagues developed digital transcriptome subtraction (DTS, an in silico method to sequentially subtract human sequences from tissue or cellular transcriptome, and discovered Merkel cell polyomavirus (MCV from Merkel cell carcinoma (MCC. Here we review the background and methods underlying the human tumor virus discoveries and explain how DTS was developed and used for the discovery of MCV.

  12. Isolating Soil Drought-Induced Genes from Maize Seedling Leaves Through Suppression Subtractive Hybridization

    Institute of Scientific and Technical Information of China (English)

    LI Hui-yong; HUANG Su-hua; SHI Yun-su2; SONG Yan-chun; ZHAO Jiu-ran; WANG Feng-ge; WANG Tian-yu; LI Yu

    2007-01-01

    In this study, a forward cDNA library was constructed by suppression subtractive hybridization using seedling leaves of CN165, a drought-tolerant maize inbred line. In the suppression subtractive hybridization (SSH) library, 672 positive clones were picked up randomly. After polymerase chain reaction (PCR) of each clone, all the single clones were sequenced. Totally 598 available sequences were obtained. After cluster analysis of the EST sequences, 80 uniESTs were obtained, among which 57 uniESTs were contigs and 23 uniESTs were singlets. The results of BLASTN showed that all the uniESTs had homologous sequences in the nr database. The BLASTX results indicated that 68 uniESTs had significant protein homology, 8 uniESTs with homology of unknown proteins and putative proteins, and 4 uniESTs without protein homology. Those drought stress-induced genes were involved in many metabolism pathways to regulate plant growth and development under drought stress.

  13. Baroclinic pressure gradient difference schemes of subtracting the local averaged density stratification in sigma coordinates models

    Institute of Scientific and Technical Information of China (English)

    ZHU Shouxian; ZHANG Wenjing

    2008-01-01

    Much has been written of the error in computing the baroclinic pressure gradient (BPG) with sigma coordinates in ocean or atmos- pheric numerical models. The usual way to reduce the error is to subtract area-averaged density stratification of the whole computa- tion region. But if there is great difference between the area-averaged and the local averaged density stratification, the error will be obvious. An example is given to show that the error from this method may be larger than that from no correction sometimes. The definition of local area is put forward. Then, four improved BPG difference schemes of subtracting the local averaged density strat- ification are designed to reduce the error. Two of them are for diagnostic calculation (density field is fixed), and the others are for prognostic calculation (density field is not fixed). The results show that the errors from these schemes all significantly decrease.

  14. Construction and analysis of a subtracted cDNA library of Betula platyphylla female inflorescence

    Institute of Scientific and Technical Information of China (English)

    WEIJi-cheng; YANGChuan-ping; WANGChao; JIANGJing

    2005-01-01

    Female inflorescence of Betula platyphylla was sampled at an interval of each two days to analyze the background of gene expression in floral phase. On the basis of SMART strategy, the driver cDNA was obtained from total RNA of the last sample and the tester cDNA was from that of the others by RT-PCR which were subsequently used to construct a subtracted cDNA library. The result of the ESTs (expression sequence tags) blastX showed that the genes in the subtracted cDNA library could be mainly clustered into 5 groups related to metabolism, transportation and signal transduction, cell cycle, stress response, and regulation. The relationship between gene expression and development was also discussed.

  15. The Application of Continuous Wavelet Transform Based Foreground Subtraction Method in 21 cm Sky Surveys

    CERN Document Server

    Gu, Junhua; Wang, Jingying; An, Tao; Chen, Wen

    2013-01-01

    We propose a continuous wavelet transform based non-parametric foreground subtraction method for the detection of redshifted 21 cm signal from the epoch of reionization. This method works based on the assumption that the foreground spectra are smooth in frequency domain, while the 21 cm signal spectrum is full of saw-tooth-like structures, thus their characteristic scales are significantly different. We can distinguish them in the wavelet coefficient space easily and perform the foreground subtraction. Compared with the traditional spectral fitting based method, our method is more tolerant to complex foregrounds. Furthermore, we also find that when the instrument has uncorrected response error, our method can also work significantly better than the spectral fitting based method. Our method can obtain similar results with the Wp smoothing method, which is also a non-parametric method, but our method consumes much less computing time.

  16. Subtraction of temperature induced phase noise in the LISA frequency band

    CERN Document Server

    Nofrarias, M; Karnesis, N; Garcia, A F; Hewitson, M; Heinzel, G; Danzmann, K

    2013-01-01

    Temperature fluctuations are expected to be one of the limiting factors for gravitational wave detectors in the very low frequency range. Here we report the characterisation of this noise source in the LISA Pathfinder optical bench and propose a method to remove its contribution from the data. Our results show that temperature fluctuations are indeed limiting our measurement below one millihertz, and that their subtraction leads to a factor 5.6 (15 dB) reduction in the noise level at the lower end of the LISA measurement band 10^{-4} Hz, which increases to 20.2 (26 dB) at even lower frequencies, i.e., 1.5x10^{-5} Hz. The method presented here can be applied to the subtraction of other noise sources in gravitational wave detectors in the general situation where multiple sensors are used to characterise the noise source.

  17. Correlated noise in networks of gravitational-wave detectors: subtraction and mitigation

    CERN Document Server

    Thrane, Eric; Schofield, Robert M S; Effler, Anamaria

    2014-01-01

    One of the key science goals of advanced gravitational-wave detectors is to observe a stochastic gravitational-wave background. However, recent work demonstrates that correlated magnetic fields from Schumann resonances can produce correlated strain noise over global distances, potentially limiting the sensitivity of stochastic background searches with advanced detectors. In this paper, we estimate the correlated noise budget for the worldwide Advanced LIGO network and conclude that correlated noise may affect upcoming measurements. We investigate the possibility of a Wiener filtering scheme to subtract correlated noise from Advanced LIGO searches, and estimate the required specifications. We also consider the possibility that residual correlated noise remains following subtraction, and we devise an optimal strategy for measuring astronomical parameters in the presence of correlated noise. Using this new formalism, we estimate the loss of sensitivity for a broadband, isotropic stochastic background search usin...

  18. Increasing LIGO sensitivity by feedforward subtraction of auxiliary length control noise

    CERN Document Server

    Meadors, Grant David; Riles, Keith

    2013-01-01

    LIGO, the Laser Interferometer Gravitational-wave Observatory, has been designed and constructed to measure gravitational wave strain via differential arm length. The LIGO 4-km Michelson arms with Fabry-Perot cavities have auxiliary length control servos for suppressing Michelson motion of the beam-splitter and arm cavity input mirrors, which degrades interferometer sensitivity. We demonstrate how a post-facto pipeline called AMPS improves a data sample from LIGO Science Run~6 with feedforward subtraction. Dividing data into 1024-second windows, AMPS numerically fits filter functions representing the frequency-domain transfer functions from Michelson length channels into the gravitational-wave strain data channel for each window, then subtracts the filtered Michelson channel noise (witness) from the strain channel (target). In this paper we describe the algorithm, assess achievable improvements in sensitivity to astrophysical sources, and consider relevance to future interferometry.

  19. Segmentation of Moving Object Using Background Subtraction Method in Complex Environments

    Directory of Open Access Journals (Sweden)

    S. Kumar

    2016-06-01

    Full Text Available Background subtraction is an extensively used approach to localize the moving object in a video sequence. However, detecting an object under the spatiotemporal behavior of background such as rippling of water, moving curtain and illumination change or low resolution is not a straightforward task. To deal with the above-mentioned problem, we address a background maintenance scheme based on the updating of background pixels by estimating the current spatial variance along the temporal line. The work is focused to immune the variation of local motion in the background. Finally, the most suitable label assignment to the motion field is estimated and optimized by using iterated conditional mode (ICM under a Markovian framework. Performance evaluation and comparisons with the other well-known background subtraction methods show that the proposed method is unaffected by the problem of aperture distortion, ghost image, and high frequency noise.

  20. Subtractive transcriptome analysis of leaf and rhizome reveals differentially expressed transcripts in Panax sokpayensis.

    Science.gov (United States)

    Gurung, Bhusan; Bhardwaj, Pardeep K; Talukdar, Narayan C

    2016-11-01

    In the present study, suppression subtractive hybridization (SSH) strategy was used to identify rare and differentially expressed transcripts in leaf and rhizome tissues of Panax sokpayensis. Out of 1102 randomly picked clones, 513 and 374 high quality expressed sequenced tags (ESTs) were generated from leaf and rhizome subtractive libraries, respectively. Out of them, 64.92 % ESTs from leaf and 69.26 % ESTs from rhizome SSH libraries were assembled into different functional categories, while others were of unknown function. In particular, ESTs encoding galactinol synthase 2, ribosomal RNA processing Brix domain protein, and cell division cycle protein 20.1, which are involved in plant growth and development, were most abundant in the leaf SSH library. Other ESTs encoding protein KIAA0664 homologue, ubiquitin-activating enzyme e11, and major latex protein, which are involved in plant immunity and defense response, were most abundant in the rhizome SSH library. Subtractive ESTs also showed similarity with genes involved in ginsenoside biosynthetic pathway, namely farnesyl pyrophosphate synthase, squalene synthase, and dammarenediol synthase. Expression profiles of selected ESTs validated the quality of libraries and confirmed their differential expression in the leaf, stem, and rhizome tissues. In silico comparative analyses revealed that around 13.75 % of unigenes from the leaf SSH library were not represented in the available leaf transcriptome of Panax ginseng. Similarly, around 18.12, 23.75, 25, and 6.25 % of unigenes from the rhizome SSH library were not represented in available root/rhizome transcriptomes of P. ginseng, Panax notoginseng, Panax quinquefolius, and Panax vietnamensis, respectively, indicating a major fraction of novel ESTs. Therefore, these subtractive transcriptomes provide valuable resources for gene discovery in P. sokpayensis and would complement the available transcriptomes from other Panax species.

  1. An Effective Leading Zero Anticipation for High Speed Floating Point Addition and Subtraction

    Directory of Open Access Journals (Sweden)

    Satish Paidi

    2012-06-01

    Full Text Available A new leading-zero anticipatory (LZA logic for high-speed floating-point addition and subtraction is proposed. The pre-decoding for normalization concurrently with addition for the significant is carried out in this logic. Shift operation of normalization in parallel with the rounding operation is also performed. The use of simple Boolean algebra allows the proposed logic to be constructed from a simple CMOS circuit.

  2. Profiling of differentially expressed genes using suppression subtractive hybridization in an equine model of chronic asthma.

    Directory of Open Access Journals (Sweden)

    Jean-Pierre Lavoie

    Full Text Available BACKGROUND: Gene expression analyses are used to investigate signaling pathways involved in diseases. In asthma, they have been primarily derived from the analysis of bronchial biopsies harvested from mild to moderate asthmatic subjects and controls. Due to ethical considerations, there is currently limited information on the transcriptome profile of the peripheral lung tissues in asthma. OBJECTIVE: To identify genes contributing to chronic inflammation and remodeling in the peripheral lung tissue of horses with heaves, a naturally occurring asthma-like condition. METHODS: Eleven adult horses (6 heaves-affected and 5 controls were studied while horses with heaves were in clinical remission (Pasture, and during disease exacerbation induced by a 30-day natural antigen challenge during stabling (Challenge. Large peripheral lung biopsies were obtained by thoracoscopy at both time points. Using suppression subtractive hybridization (SSH, lung cDNAs of controls (Pasture and Challenge and asymptomatic heaves-affected horses (Pasture were subtracted from cDNAs of horses with heaves in clinical exacerbation (Challenge. The differential expression of selected genes of interest was confirmed using quantitative PCR assay. RESULTS: Horses with heaves, but not controls, developed airway obstruction when challenged. Nine hundred and fifty cDNA clones isolated from the subtracted library were screened by dot blot array and 224 of those showing the most marked expression differences were sequenced. The gene expression pattern was confirmed by quantitative PCR in 15 of 22 selected genes. Novel genes and genes with an already defined function in asthma were identified in the subtracted cDNA library. Genes of particular interest associated with asthmatic airway inflammation and remodeling included those related to PPP3CB/NFAT, RhoA, and LTB4/GPR44 signaling pathways. CONCLUSIONS: Pathways representing new possible targets for anti-inflammatory and anti

  3. Construction of the subtractive cDNA library of injured adult and fetal rabbit skins

    Institute of Scientific and Technical Information of China (English)

    张波; 刘大维; 王正国; 朱佩芳; 周继红; 蒋建新

    2004-01-01

    Objective: Early gestational mammalian fetuses possess the amazing ability to heal cutaneous wounds in a scarless fashion. Over the past years, scientists have been working to decipher the mechanisms underlying this regenerative repair. The remarkable phenotypic differences between fetal and adult healings behoves us to learn their characteristics in genetics, which represents potentially important mechanisms involved in wound repair observed in fetal versus adult tissues. In this sense, it is reasonable to construct subtractive cDNA library for future research.Methods: Middle laparotomy and hysterotomy were performed on pregnant rabbits at 20-day gestation to expose the fetal back, and a longitudinal incision through the skin was made on the back of the fetus. The traumatized fetal skin was harvested 12 hours post-operation, the fetus control and traumatized adult skin specimens were taken at the same time. dscDNA was synthesized from total RNA of skin samples with SMART technology. Taking one of the three samples as Tester respectively and the other two as Drivers, we obtained 1 forward and 2 reverse hybridization products. After being amplified with selective polymerase chain reaction, the products were inserted into a vector, and then transferred into E.coli HB101. The colonies were screened afterwards. Results: The wounded fetuses were alive for a long time even after birth. Every determinant step, such as RNA isolation, cDNA synthesis, Rsa I digestion, adaptor ligation and hybridization, was well-operated. Subtractive efficiency identification demonstrated that the suppression subtractive hybridization (SSH) was successful. Insertion into vector and transferring to E.coli were satisfactory. Conclusions: Instead of classic SSH, an improved SSH with 2 Drivers was applied for the experiment. Results confirmed that the improved program was reasonable and correct in both theory and practice. The subtractive cDNA library we have obtained is going to be used for

  4. Digital subtraction angiography for tumours of the ear, nose and throat

    Energy Technology Data Exchange (ETDEWEB)

    Langer, M.; Zwicker, C.; Eichstaedt, H.; Maeurer, J.

    1986-08-01

    Intravenous and intra-arterial digital subtraction angiography is able to demonstrate hypervascular tumours in the ear, nose and throat territory. Direct puncture of a venous bypass used for intra-arterial chemotherapy, within the external carotid artery territory, is devoid of risk and can be used for assessing the accessibility of the tumour. Lesions of low vascularity can only be recognised by DSA on the basis of vessel displacement. These lesions are not a primary indication for examination by digital angiography. (orig).

  5. FPGA Implementation for Real-Time Background Subtraction Based on Horprasert Model

    OpenAIRE

    2012-01-01

    Background subtraction is considered the first processing stage in video surveillance systems, and consists of determining objects in movement in a scene captured by a static camera. It is an intensive task with a high computational cost. This work proposes an embedded novel architecture on FPGA which is able to extract the background on resource-limited environments and offers low degradation (produced because of the hardware-friendly model modification). In addition, the original model is e...

  6. Similarity Renormalization Group Evolution of Nucleon-Nucleon Interactions in the Subtracted Kernel Method Approach

    Energy Technology Data Exchange (ETDEWEB)

    Szpigel, S. [Centro de Ciencias e Humanidades, Universidade Presbiteriana Mackenzie, Sao Paulo, SP (Brazil); Timoteo, V.S. [Faculdade de Tecnologia, Universidade Estadual de Campinas, Limeira, SP (Brazil); Duraes, F. de O [Centro de Ciencias e Humanidades, Universidade Presbiteriana Mackenzie, Sao Paulo, SP (Brazil)

    2010-02-15

    In this work we study the Similarity Renormalization Group (SRG) evolution of effective nucleon-nucleon (NN) interactions derived using the Subtracted Kernel Method (SKM) approach. We present the results for the phaseshifts in the {sup 1}S{sub 0} channel calculated using a SRG potential evolved from an initial effective potential obtained by implementing the SKM scheme for the leading-order NN interaction in chiral effective field theory (ChEFT).

  7. Maximal abelian and Curci-Ferrari gauges in momentum subtraction at three loops

    CERN Document Server

    Bell, J M

    2015-01-01

    The vertex structure of QCD fixed in the maximal abelian gauge (MAG) and Curci-Ferrari gauge is analysed at two loops at the fully symmetric point for the 3-point functions corresponding to the three momentum subtraction (MOM) renormalization schemes. Consequently the three loop renormalization group functions are determined for each of these three schemes in each gauge using properties of the renormalization group equation.

  8. Feasibility of coronary calcium and stent image subtraction using 320-detector row CT angiography

    DEFF Research Database (Denmark)

    Fuchs, Andreas; Kühl, J Tobias; Chen, Marcus Y;

    2015-01-01

    . We defined target segments on CCTAconv as motion-free coronary segments with calcification or stent and low reader confidence. The effect of CCTAsub was assessed. No approval from the ethics committee was required according to Danish law. RESULTS: A total of 76 target segments were identified....... The use of coronary calcium image subtraction improved the reader confidence in 66% of these segments. In target segments, specificity (86% vs 65%; P

  9. Identification of floral genes for sex determination in Calamus palustris Griff. by using suppression subtractive hybridization.

    Science.gov (United States)

    Ng, C Y; Wickneswari, R; Choong, C Y

    2014-08-07

    Calamus palustris Griff. is an economically important dioecious rattan species in Southeast Asia. However, dioecy and onset of flowering at 3-4 years old render uncertainties in desired female:male seedling ratios to establish a productive seed orchard for this rattan species. We constructed a subtractive library for male floral tissue to understand the genetic mechanism for gender determination in C. palustris. The subtractive library produced 1536 clones with 1419 clones of high quality. Reverse Northern screening showed 313 clones with differential expression, and sequence analyses clustered them into 205 unigenes, including 32 contigs and 173 singletons. The subtractive library was further validated with reverse transcription-quantitative polymerase chain reaction analysis. Homology identification classified the unigenes into 12 putative functional proteins with 83% unigenes showing significant match to proteins in databases. Functional annotations of these unigenes revealed genes involved in male flower development, including MADS-box genes, pollen-related genes, phytohormones for flower development, and male flower organ development. Our results showed that the male floral genes may play a vital role in sex determination in C. palustris. The identified genes can be exploited to understand the molecular basis of sex determination in C. palustris.

  10. The IPAC Image Subtraction and Discovery Pipeline for the Intermediate Palomar Transient Factory

    Science.gov (United States)

    Masci, Frank J.; Laher, Russ R.; Rebbapragada, Umaa D.; Doran, Gary B.; Miller, Adam A.; Bellm, Eric; Kasliwal, Mansi; Ofek, Eran O.; Surace, Jason; Shupe, David L.; Grillmair, Carl J.; Jackson, Ed; Barlow, Tom; Yan, Lin; Cao, Yi; Cenko, S. Bradley; Storrie-Lombardi, Lisa J.; Helou, George; Prince, Thomas A.; Kulkarni, Shrinivas R.

    2017-01-01

    We describe the near real-time transient-source discovery engine for the intermediate Palomar Transient Factory (iPTF), currently in operations at the Infrared Processing and Analysis Center (IPAC), Caltech. We coin this system the IPAC/iPTF Discovery Engine (or IDE). We review the algorithms used for PSF-matching, image subtraction, detection, photometry, and machine-learned (ML) vetting of extracted transient candidates. We also review the performance of our ML classifier. For a limiting signal-to-noise ratio of 4 in relatively unconfused regions, bogus candidates from processing artifacts and imperfect image subtractions outnumber real transients by ≃10:1. This can be considerably higher for image data with inaccurate astrometric and/or PSF-matching solutions. Despite this occasionally high contamination rate, the ML classifier is able to identify real transients with an efficiency (or completeness) of ≃97% for a maximum tolerable false-positive rate of 1% when classifying raw candidates. All subtraction-image metrics, source features, ML probability-based real-bogus scores, contextual metadata from other surveys, and possible associations with known Solar System objects are stored in a relational database for retrieval by the various science working groups. We review our efforts in mitigating false-positives and our experience in optimizing the overall system in response to the multitude of science projects underway with iPTF.

  11. Nonlinear ultrasonic imaging method for closed cracks using subtraction of responses at different external loads.

    Science.gov (United States)

    Ohara, Yoshikazu; Horinouchi, Satoshi; Hashimoto, Makoto; Shintaku, Yohei; Yamanaka, Kazushi

    2011-08-01

    To improve the selectivity of closed cracks for objects other than cracks in ultrasonic imaging, we propose an extension of a novel imaging method, namely, subharmonic phased array for crack evaluation (SPACE) as well as another approach using the subtraction of responses at different external loads. By applying external static or dynamic loads to closed cracks, the contact state in the cracks varies, resulting in an intensity change of responses at cracks. In contrast, objects other than cracks are independent of external load. Therefore, only cracks can be extracted by subtracting responses at different loads. In this study, we performed fundamental experiments on a closed fatigue crack formed in an aluminum alloy compact tension (CT) specimen using the proposed method. We examined the static load dependence of SPACE images and the dynamic load dependence of linear phased array (PA) images by simulating the external loads with a servohydraulic fatigue testing machine. By subtracting the images at different external loads, we show that this method is useful in extracting only the intensity change of responses related to closed cracks, while canceling the responses of objects other than cracks.

  12. The impact of point source subtraction residuals on 21 cm Epoch of Reionization estimation

    CERN Document Server

    Trott, Cathryn M; Tingay, Steven J

    2012-01-01

    Precise subtraction of foreground sources is crucial for detecting and estimating 21cm HI signals from the Epoch of Reionization (EoR). We quantify how imperfect point source subtraction due to limitations of the measurement dataset yields structured residual signal in the dataset. We use the Cramer-Rao lower bound, as a metric for quantifying the precision with which a parameter may be measured, to estimate the residual signal in a visibility dataset due to imperfect point source subtraction. We then propagate these residuals into two metrics of interest for 21cm EoR experiments - the angular and two-dimensional power spectrum - using a combination of full analytic covariant derivation, analytic variant derivation, and covariant Monte Carlo simulations. This methodology differs from previous work in two ways: (1) it uses information theory to set the point source position error, rather than assuming a global root-mean-square error, and (2) it describes a method for propagating the errors analytically, thereb...

  13. Scatter-to-primary based scatter fractions for transmission-dependent convolution subtraction of SPECT images.

    Science.gov (United States)

    Larsson, Anne; Johansson, Lennart

    2003-11-21

    In single photon emission computed tomography (SPECT), transmission-dependent convolution subtraction has been shown to be useful when correcting for scattered events. The method is based on convolution subtraction, but includes a matrix of scatter fractions instead of a global scatter fraction. The method can be extended to iteratively improve the scatter estimate, but in this note we show that this requires a modification of the theory to use scatter-to-total scatter fractions for the first iteration only and scatter-to-primary fractions thereafter. To demonstrate this, scatter correction is performed on a Monte Carlo simulated image of a point source of activity in water. The modification of the theory is compared to corrections where the scatter fractions are based on the scatter-to-total ratio, using one and ten iterations. The resulting ratios of subtracted to original counts are compared to the true scatter-to-total ratio of the simulation and the most accurate result is found for our modification of the theory.

  14. DESIGN STUDY: INTEGER SUBTRACTION OPERATION TEACHING LEARNING USING MULTIMEDIA IN PRIMARY SCHOOL

    Directory of Open Access Journals (Sweden)

    Rendi Muhammad Aris

    2016-12-01

    Full Text Available This study aims to develop a learning trajectory to help students understand concept of subtraction of integers using multimedia in the fourth grade. This study is thematic integrative learning in Curriculum 2013 PMRI based. The method used is design research consists of three stages; preparing for the experiment, design experiment, retrospective analysis. The studied was conducted on 20 students of grade four SDN 1 Muara Batun, OKI. The activities of students in this study consisted of six learning trajectories. The first activity asks the students to classify heroism and non-heroism acts, summarize, and classify integers and non-integer. The second activity asks the students to answer the questions in the film given. The third activity asks students to count the remaining gravel in the film. The fourth activity asks students to count remaining spent money in the film. The fifth activity invites students to play rubber seeds in the bag. The last activity asks students to answer the questions in the student worksheet. The media used along the learning activities are a ruler, rubber seed, student worksheet, money, gravel, and film. The results indicate that the learning trajectory using multimedia help students understand the concept of integer subtraction integer. Keywords: Subtraction Integer, PMRI, Multimedia DOI: http://dx.doi.org/10.22342/jme.8.1.3233.95-102

  15. Ability of subtraction and dynamic MR imaging to detect breast tumors. Comparison with ultrasonography and mammography

    Energy Technology Data Exchange (ETDEWEB)

    Terao, Eri; Takeuchi, Hiroaki; Iwamura, Akira; Murakami, Yoshitaka; Harada, Junta; Tada, Shinpei (Jikei Univ., Tokyo (Japan). School of Medicine)

    1994-09-01

    We evaluated the ability of subtraction and dynamic MR imaging to accurately detect breast tumors. Sixty-five breast carcinomas and 24 fibroadenomas were examined by an SE pulse sequence using a 0.2 Tesla unit. Subtraction MR images were obtained every minute during dynamic study with Gd-DTPA. Almost all breast tumors were seen as very bright masses, and the margin of the mass was clearly demonstrated on subtraction MR images. Breast carcinomas and fibroadenomas showed characteristic time-intensity curves on dynamic study. Time-intensity curves of the early peak type and plateau type were seen in 97% of breast carcinomas, while the gradually increasing type was seen in 92% of fibroadenomas. The detectability of breast carcinoma was 98% by MRI, 98% by ultrasonography, and 87% by mammography. That of fibroadenoma was 95% by MRI, 91% by ultrasonography and 60% by mammography. Sensitivity and specificity for breast carcinoma were 98% and 92% for MRI and 97% and 71% for ultrasonography. For fibroadenoma, they were 96% and 98% for MRI and 89% and 92% for ultrasonography. (author).

  16. A comparison of segmentation and emission subtraction for singles transmission in PET

    Energy Technology Data Exchange (ETDEWEB)

    Smith, R.J.; Karp, J.S.; Benard, F.; Alavi, A. [Univ. of Pennsylvania, Philadelphia, PA (United States). Dept. of Radiology; Gualtieri, E.; Muehllehner, G.; Geagan, M. [UGM Medical Systems, Philadelphia, PA (United States)

    1998-06-01

    Single photon transmission scans, using {sup 137}Cs (662 keV gamma rays), are performed post-injection for clinical whole body PET studies. Two methods of processing the transmission data are investigated. The first method segments the transmission image into lung and soft tissues volumes. Average attenuation coefficients for 511 keV are applied and this transmission image is forward projected for attenuation correction. In the second method short emission contamination (EC) scans are performed after the singles transmission scans. These are singles transmission scans without a {sup 137}Cs transmission source. These EC scans are then subtracted from the transmission scans to remove contamination of the 662 keV energy window by 511 keV emission gamma rays. From ten patients studied by this method, the EC subtracted transmission images have average soft tissue attenuation coefficients of 0.074/cm, compared to the expected value of 0.086/cm for 662 keV gamma rays. Simple scaling of these transmission images to 511 keV values (0.095/cm) results in quantitative attenuation correction. A comparison of the two methods is made for these ten patient studies. Both methods result in accurate attenuation correction. The segmentation method performs low noise attenuation correction but is more limited to torso studies with the limbs out of the FOV. The EC subtraction method is more versatile and is applicable to the entire body but results in some more noise in the fully corrected images.

  17. The IPAC Image Subtraction and Discovery Pipeline for the Intermediate Palomar Transient Factory

    Science.gov (United States)

    Masci, Frank J.; Laher, Russ R.; Rebbapragada, Umaa D.; Doran, Gary B.; Miller, Adam A.; Bellm, Eric; Kasliwal, Mansi; Ofek, Eran O.; Surace, Jason; Shupe, David L.; hide

    2016-01-01

    We describe the near real-time transient-source discovery engine for the intermediate Palomar Transient Factory (iPTF), currently in operations at the Infrared Processing and Analysis Center (IPAC), Caltech. We coin this system the IPAC/iPTF Discovery Engine (or IDE). We review the algorithms used for PSF-matching, image subtraction, detection, photometry, and machine-learned (ML) vetting of extracted transient candidates. We also review the performance of our ML classifier. For a limiting signal-to-noise ratio of 4 in relatively unconfused regions, bogus candidates from processing artifacts and imperfect image subtractions outnumber real transients by approximately equal to 10:1. This can be considerably higher for image data with inaccurate astrometric and/or PSF-matching solutions. Despite this occasionally high contamination rate, the ML classifier is able to identify real transients with an efficiency (or completeness) of approximately equal to 97% for a maximum tolerable false-positive rate of 1% when classifying raw candidates. All subtraction-image metrics, source features, ML probability-based real-bogus scores, contextual metadata from other surveys, and possible associations with known Solar System objects are stored in a relational database for retrieval by the various science working groups. We review our efforts in mitigating false-positives and our experience in optimizing the overall system in response to the multitude of science projects underway with iPTF.

  18. Fast washout of thallium-201 from area of myocardial infarction: possible artifact of background subtraction

    Energy Technology Data Exchange (ETDEWEB)

    Brown, K.A.; Benoit, L.; Clements, J.P.; Wackers, F.J.

    1987-06-01

    A recent report described a pattern of reverse redistribution on poststreptokinase /sup 201/Tl studies which was believed to be due to rapid washout of /sup 201/Tl from the infarct area related to reperfusion of the infarct vessel. We have also observed the phenomenon of rapid washout of /sup 201/Tl from the area of infarction in the absence of thrombolytic therapy. This study was undertaken to test the hypothesis that rapid washout of /sup 201/Tl from an area of infarction is an artifact of background subtraction usually employed in analysis of washout. A total of 61 patients with previous myocardial infarction who underwent cardiac catheterization and exercise /sup 201/Tl imaging were examined. Thallium-201 images were analyzed using a validated quantitative method employing interpolative background correction. Abnormally increased /sup 201/Tl washout was noted in 11 infarct segments in 10 (18%) patients. Infarct segments with rapid washout had significantly less initial uptake, and more severe associated wall motion abnormalities than infarct segments with normal washout. When quantitative analysis was repeated without background subtraction, no segments with rapid washout were observed. A phantom model was constructed to further test our hypothesis. The frequency of observed rapid washout was directly related to the severity of the initial defect and was entirely dependent upon utilizing background correction during the quantitative analysis. Our study suggests that rapid washout of /sup 201/Tl in an area of previous infarction reflects an artifact of background subtraction involved with standard quantitative analysis.

  19. Regression-based algorithm for bulk motion subtraction in optical coherence tomography angiography.

    Science.gov (United States)

    Camino, Acner; Jia, Yali; Liu, Gangjun; Wang, Jie; Huang, David

    2017-06-01

    We developed an algorithm to remove decorrelation noise due to bulk motion in optical coherence tomography angiography (OCTA) of the posterior eye. In this algorithm, OCTA B-frames were divided into segments within which the bulk motion velocity could be assumed to be constant. This velocity was recovered using linear regression of decorrelation versus the logarithm of reflectance in axial lines (A-lines) identified as bulk tissue by percentile analysis. The fitting parameters were used to calculate a reflectance-adjusted upper bound threshold for bulk motion decorrelation. Below this threshold, voxels are identified as non-flow tissue, their flow values are set to zeros. Above this threshold, the voxels are identified as flow voxels and bulk motion velocity is subtracted from each using a nonlinear decorrelation-velocity relationship previously established in laboratory flow phantoms. Compared to the simpler median-subtraction method, the regression-based bulk motion subtraction improved angiogram signal-to-noise ratio, contrast, vessel density repeatability, and bulk motion noise cleanup in the foveal avascular zone, while preserving the connectivity of the vascular networks in the angiogram.

  20. Some Doubts on the Validity of the Foreground Galactic Contribution Subtraction from Microwave Anisotropies

    Indian Academy of Sciences (India)

    Martín López-Corredoira

    2007-06-01

    The Galactic foreground contamination in CMBR anisotropies, especially from the dust component, is not easily separable from the cosmological or extragalactic component. In this paper, some doubts will be raised concerning the validity of the methods used until now to remove Galactic dust emission and will show that none of them achieves its goal. First, I review the recent bibliography on the topic and discuss critically the methods of foreground subtraction: the cross-correlation with templates, analysis assuming the spectral shape of the Galactic components, the ``maximum entropy method”, ``internal linear combination”, and ``wavelet-based high resolution fitting of internal templates”. Second, I analyse the Galactic latitude dependence from WMAP data. The frequency dependence is discussed with data in the available literature. The result is that all methods of subtracting the Galactic contamination are inaccurate. The Galactic latitude dependence analysis or the frequency dependence of the anisotropies in the range 50–250 GHz put a constraint on the maximum Galactic contribution in the power spectrum to be less than ∼ 10% (68% C. L.) for an ∼ 1 degree scale, and possibly higher for larger scales. The origin of most of the signals in the CMBR anisotropies is not Galactic. In any case, the subtraction of the galaxy is not accurate enough to allow a ``precision Cosmology”; other sources of contamination (extragalactic, solar system) are also present.

  1. Subtraction Radiographic Assessment of Underlying Dentin After Partial Carious Dentin Removal in Primary Teeth.

    Science.gov (United States)

    Phonghanyudh, Araya; Ruangdit, Chayathorn; Pornprasertsuk-D Amrongsri, Suchaya; Phanthumvanit, Prathip

    2017-09-21

    To assess the one-year outcome of glass-ionomer cement (GIC) restorations with partial carious dentin removal in primary molars using digital subtraction radiographs. Children ages 6-8 years were recruited. Forty-nine primary molars with deep carious lesions were studied. The carious dentin was removed at the dentoenamel junction (DEJ) and restored with GIC. Digital radiographs were taken immediately after restoration, and at 6 and 12 months after restoration. The sets of digital radiographs were subtracted and analysed using Image-Pro Plus software. At the 12-month follow-up, 38 of the original 49 primary molars were analysed. No postoperative pain or signs of pulp pathology were reported. 76% and 87% of molars showed an increase in density of the studied areas compared to control areas at 6- and 12- month follow-ups, respectively. The density of digital subtraction radiographs increased to 5.3 and 8.2 at 6 and 12 months from baseline, respectively. The mean density of the areas under restoration at 6 months and 12 months was statistically significantly higher than at baseline (paired t-test; p carious dentin removal in primary molars showed a high potential for dentin remineralisation after 1 year.

  2. Identification of proteins involved in the functioning of Riftia pachyptila symbiosis by Subtractive Suppression Hybridization

    Directory of Open Access Journals (Sweden)

    Lallier François H

    2007-09-01

    Full Text Available Abstract Background Since its discovery around deep sea hydrothermal vents of the Galapagos Rift about 30 years ago, the chemoautotrophic symbiosis between the vestimentiferan tubeworm Riftia pachyptila and its symbiotic sulfide-oxidizing γ-proteobacteria has been extensively studied. However, studies on the tubeworm host were essentially targeted, biochemical approaches. We decided to use a global molecular approach to identify new proteins involved in metabolite exchanges and assimilation by the host. We used a Subtractive Suppression Hybridization approach (SSH in an unusual way, by comparing pairs of tissues from a single individual. We chose to identify the sequences preferentially expressed in the branchial plume tissue (the only organ in contact with the sea water and in the trophosome (the organ housing the symbiotic bacteria using the body wall as a reference tissue because it is supposedly not involved in metabolite exchanges in this species. Results We produced four cDNA libraries: i body wall-subtracted branchial plume library (BR-BW, ii and its reverse library, branchial plume-subtracted body wall library (BW-BR, iii body wall-subtracted trophosome library (TR-BW, iv and its reverse library, trophosome-subtracted body wall library (BW-TR. For each library, we sequenced about 200 clones resulting in 45 different sequences on average in each library (58 and 59 cDNAs for BR-BW and TR-BW libraries respectively. Overall, half of the contigs matched records found in the databases with good E-values. After quantitative PCR analysis, it resulted that 16S, Major Vault Protein, carbonic anhydrase (RpCAbr, cathepsin and chitinase precursor transcripts were highly represented in the branchial plume tissue compared to the trophosome and the body wall tissues, whereas carbonic anhydrase (RpCAtr, myohemerythrin, a putative T-Cell receptor and one non identified transcript were highly specific of the trophosome tissue. Conclusion Quantitative PCR

  3. Isolation and Expression Analysis of Novel Silicon Absorption Gene from Roots of Mangrove (Rhizophora apiculata via Suppression Subtractive Hybridization

    Directory of Open Access Journals (Sweden)

    Mahbod Sahebi

    2014-01-01

    Full Text Available Silicon (Si is the second most abundant element in soil after oxygen. It is not an essential element for plant growth and formation but plays an important role in increasing plant tolerance towards different kinds of abiotic and biotic stresses. The molecular mechanism of Si absorption and accumulation may differ between plants, such as monocotyledons and dicotyledons. Silicon absorption and accumulation in mangrove plants are affected indirectly by some proteins rich in serine and proline amino acids. The expression level of the genes responsible for Si absorption varies in different parts of plants. In this study, Si is mainly observed in the epidermal roots’ cell walls of mangrove plants compared to other parts. The present work was carried out to discover further information on Si stress responsive genes in Rhizophora apiculata, using the suppression subtractive hybridization technique. To construct the cDNA library, two-month-old seedlings were exposed to 0.5, 1, and 1.5 mM SiO2 for 15 hrs and for 1 to 6 days resulting in a total of 360 high quality ESTs gained. Further examination by RT-PCR and real-time qRT-PCR showed the expression of a candidate gene of serine-rich protein.

  4. Isolation and expression analysis of novel silicon absorption gene from roots of mangrove (Rhizophora apiculata) via suppression subtractive hybridization.

    Science.gov (United States)

    Sahebi, Mahbod; Hanafi, Mohamed M; Abdullah, Siti Nor Akmar; Rafii, Mohd Y; Azizi, Parisa; Nejat, Naghmeh; Idris, Abu Seman

    2014-01-01

    Silicon (Si) is the second most abundant element in soil after oxygen. It is not an essential element for plant growth and formation but plays an important role in increasing plant tolerance towards different kinds of abiotic and biotic stresses. The molecular mechanism of Si absorption and accumulation may differ between plants, such as monocotyledons and dicotyledons. Silicon absorption and accumulation in mangrove plants are affected indirectly by some proteins rich in serine and proline amino acids. The expression level of the genes responsible for Si absorption varies in different parts of plants. In this study, Si is mainly observed in the epidermal roots' cell walls of mangrove plants compared to other parts. The present work was carried out to discover further information on Si stress responsive genes in Rhizophora apiculata, using the suppression subtractive hybridization technique. To construct the cDNA library, two-month-old seedlings were exposed to 0.5, 1, and 1.5 mM SiO2 for 15 hrs and for 1 to 6 days resulting in a total of 360 high quality ESTs gained. Further examination by RT-PCR and real-time qRT-PCR showed the expression of a candidate gene of serine-rich protein.

  5. Suppression subtractive hybridization method for the identification of a new strain of murine hepatitis virus from xenografted SCID mice.

    Science.gov (United States)

    Islam, Mohammed M; Toohey, Brendan; Purcell, Damian F J; Kannourakis, George

    2015-12-01

    During attempts to clone retroviral determinants associated with a mouse model of Langerhans cell histiocytosis (LCH), suppression subtractive hybridization (SSH) was used to identify unique viruses in the liver of severe combined immunodeficiency (SCID) mice transplanted with LCH tissues. A partial genomic sequence of a murine coronavirus was identified, and the whole genome (31428 bp) of the coronavirus was subsequently sequenced using PCR cloning techniques. Nucleotide sequence comparisons revealed that the genome sequence of the new virus was 91-93% identical to those of known murine hepatitis viruses (MHVs). The predicted open reading frame from the nucleotide sequence encoded all known proteins of MHVs. Analysis at the protein level showed that the virus was closely related to the highly virulent MHV-JHM strain. The virus strain was named MHV-MI. No type D retroviruses were found. Degenerate PCR targeting of type D retrovirus and 5'-RACE targeting of other types of retroviruses confirmed the absence of any retroviral association with the LCH xenografted SCID mice.

  6. Behavior subtraction

    Science.gov (United States)

    Jodoin, Pierre-Marc; Saligrama, Venkatesh; Konrad, Janusz

    2008-01-01

    Network video cameras, invented in the last decade or so, permit today pervasive, wide-area visual surveillance. However, due to the vast amounts of visual data that such cameras produce human-operator monitoring is not possible and automatic algorithms are needed. One monitoring task of particular interest is the detection of suspicious behavior, i.e., identification of individuals or objects whose behavior differs from behavior usually observed. Many methods based on object path analysis have been developed to date (motion detection followed by tracking and inferencing) but they are sensitive to motion detection and tracking errors and are also computationally complex. We propose a new surveillance method capable of abnormal behavior detection without explicit estimation of object paths. Our method is based on a simple model of video dynamics. We propose one practical implementation of this general model via temporal aggregation of motion detection labels. Our method requires little processing power and memory, is robust to motion segmentation errors, and general enough to monitor humans, cars or any other moving objects in uncluttered as well as highly-cluttered scenes. Furthermore, on account of its simplicity, our method can provide performance guarantees. It is also robust in harsh environments (jittery cameras, rain/snow/fog).

  7. A Method of Time-Intensity Curve Calculation for Vascular Perfusion of Uterine Fibroids Based on Subtraction Imaging with Motion Correction

    Science.gov (United States)

    Zhu, Xinjian; Wu, Ruoyu; Li, Tao; Zhao, Dawei; Shan, Xin; Wang, Puling; Peng, Song; Li, Faqi; Wu, Baoming

    2016-12-01

    The time-intensity curve (TIC) from contrast-enhanced ultrasound (CEUS) image sequence of uterine fibroids provides important parameter information for qualitative and quantitative evaluation of efficacy of treatment such as high-intensity focused ultrasound surgery. However, respiration and other physiological movements inevitably affect the process of CEUS imaging, and this reduces the accuracy of TIC calculation. In this study, a method of TIC calculation for vascular perfusion of uterine fibroids based on subtraction imaging with motion correction is proposed. First, the fibroid CEUS recording video was decoded into frame images based on the record frame rate. Next, the Brox optical flow algorithm was used to estimate the displacement field and correct the motion between two frames based on warp technique. Then, subtraction imaging was performed to extract the positional distribution of vascular perfusion (PDOVP). Finally, the average gray of all pixels in the PDOVP from each image was determined, and this was considered the TIC of CEUS image sequence. Both the correlation coefficient and mutual information of the results with proposed method were larger than those determined using the original method. PDOVP extraction results have been improved significantly after motion correction. The variance reduction rates were all positive, indicating that the fluctuations of TIC had become less pronounced, and the calculation accuracy has been improved after motion correction. This proposed method can effectively overcome the influence of motion mainly caused by respiration and allows precise calculation of TIC.

  8. Correction for scatter and septal penetration using convolution subtraction methods and model-based compensation in {sup 123}I brain SPECT imaging-a Monte Carlo study

    Energy Technology Data Exchange (ETDEWEB)

    Larsson, Anne [Department of Radiation Sciences, Radiation Physics, Umeaa University, SE-901 87 Umeaa (Sweden); Ljungberg, Michael [Medical Radiation Physics, Department of Clinical Sciences, Lund, Lund University, SE-221 85 Lund (Sweden); Mo, Susanna Jakobson [Department of Radiation Sciences, Diagnostic Radiology, Umeaa University, SE-901 87 Umeaa (Sweden); Riklund, Katrine [Department of Radiation Sciences, Diagnostic Radiology, Umeaa University, SE-901 87 Umeaa (Sweden); Johansson, Lennart [Department of Radiation Sciences, Radiation Physics, Umeaa University, SE-901 87 Umeaa (Sweden)

    2006-11-21

    Scatter and septal penetration deteriorate contrast and quantitative accuracy in single photon emission computed tomography (SPECT). In this study four different correction techniques for scatter and septal penetration are evaluated for {sup 123}I brain SPECT. One of the methods is a form of model-based compensation which uses the effective source scatter estimation (ESSE) for modelling scatter, and collimator-detector response (CDR) including both geometric and penetration components. The other methods, which operate on the 2D projection images, are convolution scatter subtraction (CSS) and two versions of transmission dependent convolution subtraction (TDCS), one of them proposed by us. This method uses CSS for correction for septal penetration, with a separate kernel, and TDCS for scatter correction. The corrections are evaluated for a dopamine transporter (DAT) study and a study of the regional cerebral blood flow (rCBF), performed with {sup 123}I. The images are produced using a recently developed Monte Carlo collimator routine added to the program SIMIND which can include interactions in the collimator. The results show that the method included in the iterative reconstruction is preferable to the other methods and that the new TDCS version gives better results compared with the other 2D methods.

  9. Correction for scatter and septal penetration using convolution subtraction methods and model-based compensation in 123I brain SPECT imaging-a Monte Carlo study.

    Science.gov (United States)

    Larsson, Anne; Ljungberg, Michael; Mo, Susanna Jakobson; Riklund, Katrine; Johansson, Lennart

    2006-11-21

    Scatter and septal penetration deteriorate contrast and quantitative accuracy in single photon emission computed tomography (SPECT). In this study four different correction techniques for scatter and septal penetration are evaluated for 123I brain SPECT. One of the methods is a form of model-based compensation which uses the effective source scatter estimation (ESSE) for modelling scatter, and collimator-detector response (CDR) including both geometric and penetration components. The other methods, which operate on the 2D projection images, are convolution scatter subtraction (CSS) and two versions of transmission dependent convolution subtraction (TDCS), one of them proposed by us. This method uses CSS for correction for septal penetration, with a separate kernel, and TDCS for scatter correction. The corrections are evaluated for a dopamine transporter (DAT) study and a study of the regional cerebral blood flow (rCBF), performed with 123I. The images are produced using a recently developed Monte Carlo collimator routine added to the program SIMIND which can include interactions in the collimator. The results show that the method included in the iterative reconstruction is preferable to the other methods and that the new TDCS version gives better results compared with the other 2D methods.

  10. Correction for scatter and septal penetration using convolution subtraction methods and model-based compensation in 123I brain SPECT imaging—a Monte Carlo study

    Science.gov (United States)

    Larsson, Anne; Ljungberg, Michael; Jakobson Mo, Susanna; Riklund, Katrine; Johansson, Lennart

    2006-11-01

    Scatter and septal penetration deteriorate contrast and quantitative accuracy in single photon emission computed tomography (SPECT). In this study four different correction techniques for scatter and septal penetration are evaluated for 123I brain SPECT. One of the methods is a form of model-based compensation which uses the effective source scatter estimation (ESSE) for modelling scatter, and collimator-detector response (CDR) including both geometric and penetration components. The other methods, which operate on the 2D projection images, are convolution scatter subtraction (CSS) and two versions of transmission dependent convolution subtraction (TDCS), one of them proposed by us. This method uses CSS for correction for septal penetration, with a separate kernel, and TDCS for scatter correction. The corrections are evaluated for a dopamine transporter (DAT) study and a study of the regional cerebral blood flow (rCBF), performed with 123I. The images are produced using a recently developed Monte Carlo collimator routine added to the program SIMIND which can include interactions in the collimator. The results show that the method included in the iterative reconstruction is preferable to the other methods and that the new TDCS version gives better results compared with the other 2D methods.

  11. Planet detection down to a few $\\lambda$/D: an RSDI/TLOCI approach to PSF subtraction

    CERN Document Server

    Gerard, Benjamin L

    2016-01-01

    Most current high contrast imaging point spread function (PSF) subtraction algorithms use some form of a least-squares noise minimization to find exoplanets that are, before post-processing, often hidden below the instrumental speckle noise. In the current standard PSF subtraction algorithms, a set of reference images is derived from the target image sequence to subtract each target image, using Angular and/or Simultaneous Spectral Differential Imaging (ADI, SSDI, respectively). However, to avoid excessive exoplanet self-subtraction, ADI and SSDI (in the absence of a strong spectral feature) severely limit the available number of reference images at small separations. This limits the performance of the least-squares algorithm, resulting in lower sensitivity to exoplanets at small angular separations. Possible solutions are to use additional reference images by acquiring longer sequences, use SSDI if the exoplanet is expected to show strong spectral features, or use images acquired on other targets. The latter...

  12. Sigma pole position and errors of a once and twice subtracted dispersive analysis of pi-pi scattering data

    CERN Document Server

    Kaminski, R; Grynkiewicz, P; Peláez, J R

    2009-01-01

    We show how the new precise data on kaon decays together with forward dispersion relations, sum rules and once- and twice-subtracted Roy's equations allow for a precise determination of the sigma meson pole position. We present a comparison and a study of the different sources of uncertainties when using either once- or twice-subtracted Roy's equations to analyze the data. Finally we present a preliminary determination of the sigma pole from the constrained dispersive data analysis.

  13. Visualization of Minkowski operations by computer graphics techniques

    NARCIS (Netherlands)

    Roerdink, J.B.T.M.; Blaauwgeers, G.S.M.; Serra, J; Soille, P

    1994-01-01

    We consider the problem of visualizing 3D objects defined as a Minkowski addition or subtraction of elementary objects. It is shown that such visualizations can be obtained by using techniques from computer graphics such as ray tracing and Constructive Solid Geometry. Applications of the method are

  14. Subtraction of unidirectionally encoded images for suppression of heavily isotropic objects (SUSHI) for selective visualization of peripheral nerves

    Energy Technology Data Exchange (ETDEWEB)

    Takahara, Taro; Kwee, Thomas C.; Hendrikse, Jeroen; Niwa, Tetsu; Mali, Willem P.T.M.; Luijten, Peter R. [University Medical Center Utrecht, Department of Radiology, Utrecht (Netherlands); Van Cauteren, Marc [Philips Healthcare, Asia Pacific, Tokyo (Japan); Koh, Dow-Mu [Royal Marsden Hospital, Department of Radiology, Sutton (United Kingdom)

    2011-02-15

    The aim of this study was to introduce and assess a new magnetic resonance (MR) technique for selective peripheral nerve imaging, called ''subtraction of unidirectionally encoded images for suppression of heavily isotropic objects'' (SUSHI). Six volunteers underwent diffusion-weighted MR neurography (DW-MRN) of the brachial plexus, and seven volunteers underwent DW-MRN of the sciatic, common peroneal, and tibial nerves at the level of the knee, at 1.5 T. DW-MRN images with SUSHI (DW-MRN{sub SUSHI}) and conventional DW-MRN images (DW-MRN{sub AP}) were displayed using a coronal maximum intensity projection and evaluated by two independent observers regarding signal suppression of lymph nodes, bone marrow, veins, and articular fluids and regarding signal intensity of nerves and ganglia, using five-point grading scales. Scores of DW-MRN{sub SUSHI} were compared to those of DW-MRN{sub AP} using Wilcoxon tests. Suppression of lymph nodes around the brachial plexus and suppression of articular fluids at the level of the knee at DW-MRN{sub SUSHI} was significantly better than that at DW-MRN{sub AP} (P < 0.05). However, overall signal intensity of brachial plexus nerves and ganglia at DW-MRN{sub SUSHI} was significantly lower than that at DW-MRN{sub AP} (P < 0.05). On the other hand, signal intensity of the sciatic, common peroneal, and tibial nerves at the level of the knee at DW-MRN{sub SUSHI} was judged as significantly better than that at DW-MRN{sub AP} (P < 0.05). The SUSHI technique allows more selective visualization of the sciatic, common peroneal, and tibial nerves at the level of the knee but is less useful for brachial plexus imaging because signal intensity of the brachial plexus nerves and ganglia can considerably be decreased. (orig.)

  15. Quantifying the relative contributions of divisive and subtractive feedback to rhythm generation.

    Directory of Open Access Journals (Sweden)

    Joël Tabak

    2011-04-01

    Full Text Available Biological systems are characterized by a high number of interacting components. Determining the role of each component is difficult, addressed here in the context of biological oscillations. Rhythmic behavior can result from the interplay of positive feedback that promotes bistability between high and low activity, and slow negative feedback that switches the system between the high and low activity states. Many biological oscillators include two types of negative feedback processes: divisive (decreases the gain of the positive feedback loop and subtractive (increases the input threshold that both contribute to slowly move the system between the high- and low-activity states. Can we determine the relative contribution of each type of negative feedback process to the rhythmic activity? Does one dominate? Do they control the active and silent phase equally? To answer these questions we use a neural network model with excitatory coupling, regulated by synaptic depression (divisive and cellular adaptation (subtractive feedback. We first attempt to apply standard experimental methodologies: either passive observation to correlate the variations of a variable of interest to system behavior, or deletion of a component to establish whether a component is critical for the system. We find that these two strategies can lead to contradictory conclusions, and at best their interpretive power is limited. We instead develop a computational measure of the contribution of a process, by evaluating the sensitivity of the active (high activity and silent (low activity phase durations to the time constant of the process. The measure shows that both processes control the active phase, in proportion to their speed and relative weight. However, only the subtractive process plays a major role in setting the duration of the silent phase. This computational method can be used to analyze the role of negative feedback processes in a wide range of biological rhythms.

  16. Subtracted diversity array identifies novel molecular markers including retrotransposons for fingerprinting Echinacea species.

    Directory of Open Access Journals (Sweden)

    Alexandra Olarte

    Full Text Available Echinacea, native to the Canadian prairies and the prairie states of the United States, has a long tradition as a folk medicine for the Native Americans. Currently, Echinacea are among the top 10 selling herbal medicines in the U.S. and Europe, due to increasing popularity for the treatment of common cold and ability to stimulate the immune system. However, the genetic relationship within the species of this genus is unclear, making the authentication of the species used for the medicinal industry more difficult. We report the construction of a novel Subtracted Diversity Array (SDA for Echinacea species and demonstrate the potential of this array for isolating highly polymorphic sequences. In order to selectively isolate Echinacea-specific sequences, a Suppression Subtractive Hybridization (SSH was performed between a pool of twenty-four Echinacea genotypes and a pool of other angiosperms and non-angiosperms. A total of 283 subtracted genomic DNA (gDNA fragments were amplified and arrayed. Twenty-seven Echinacea genotypes including four that were not used in the array construction could be successfully discriminated. Interestingly, unknown samples of E. paradoxa and E. purpurea could be unambiguously identified from the cluster analysis. Furthermore, this Echinacea-specific SDA was also able to isolate highly polymorphic retrotransposon sequences. Five out of the eleven most discriminatory features matched to known retrotransposons. This is the first time retrotransposon sequences have been used to fingerprint Echinacea, highlighting the potential of retrotransposons as based molecular markers useful for fingerprinting and studying diversity patterns in Echinacea.

  17. Phasic Firing and Coincidence Detection by Subthreshold Negative Feedback: Divisive or Subtractive or, Better, Both

    Science.gov (United States)

    Huguet, Gemma; Meng, Xiangying; Rinzel, John

    2017-01-01

    Phasic neurons typically fire only for a fast-rising input, say at the onset of a step current, but not for steady or slow inputs, a property associated with type III excitability. Phasic neurons can show extraordinary temporal precision for phase locking and coincidence detection. Exemplars are found in the auditory brain stem where precise timing is used in sound localization. Phasicness at the cellular level arises from a dynamic, voltage-gated, negative feedback that can be recruited subthreshold, preventing the neuron from reaching spike threshold if the voltage does not rise fast enough. We consider two mechanisms for phasicness: a low threshold potassium current (subtractive mechanism) and a sodium current with subthreshold inactivation (divisive mechanism). We develop and analyze three reduced models with either divisive or subtractive mechanisms or both to gain insight into the dynamical mechanisms for the potentially high temporal precision of type III-excitable neurons. We compare their firing properties and performance for a range of stimuli. The models have characteristic non-monotonic input-output relations, firing rate vs. input intensity, for either stochastic current injection or Poisson-timed excitatory synaptic conductance trains. We assess performance according to precision of phase-locking and coincidence detection by the models' responses to repetitive packets of unitary excitatory synaptic inputs with more or less temporal coherence. We find that each mechanism contributes features but best performance is attained if both are present. The subtractive mechanism confers extraordinary precision for phase locking and coincidence detection but only within a restricted parameter range when the divisive mechanism of sodium inactivation is inoperative. The divisive mechanism guarantees robustness of phasic properties, without compromising excitability, although with somewhat less precision. Finally, we demonstrate that brief transient inhibition if

  18. Subtracted Diversity Array Identifies Novel Molecular Markers Including Retrotransposons for Fingerprinting Echinacea Species

    Science.gov (United States)

    Olarte, Alexandra; Mantri, Nitin; Nugent, Gregory; Pang, Edwin C. K.

    2013-01-01

    Echinacea, native to the Canadian prairies and the prairie states of the United States, has a long tradition as a folk medicine for the Native Americans. Currently, Echinacea are among the top 10 selling herbal medicines in the U.S. and Europe, due to increasing popularity for the treatment of common cold and ability to stimulate the immune system. However, the genetic relationship within the species of this genus is unclear, making the authentication of the species used for the medicinal industry more difficult. We report the construction of a novel Subtracted Diversity Array (SDA) for Echinacea species and demonstrate the potential of this array for isolating highly polymorphic sequences. In order to selectively isolate Echinacea-specific sequences, a Suppression Subtractive Hybridization (SSH) was performed between a pool of twenty-four Echinacea genotypes and a pool of other angiosperms and non-angiosperms. A total of 283 subtracted genomic DNA (gDNA) fragments were amplified and arrayed. Twenty-seven Echinacea genotypes including four that were not used in the array construction could be successfully discriminated. Interestingly, unknown samples of E. paradoxa and E. purpurea could be unambiguously identified from the cluster analysis. Furthermore, this Echinacea-specific SDA was also able to isolate highly polymorphic retrotransposon sequences. Five out of the eleven most discriminatory features matched to known retrotransposons. This is the first time retrotransposon sequences have been used to fingerprint Echinacea, highlighting the potential of retrotransposons as based molecular markers useful for fingerprinting and studying diversity patterns in Echinacea. PMID:23940565

  19. A generic plant RNA isolation method suitable for RNA-Seq and suppression subtractive hybridization.

    Science.gov (United States)

    Zhu, Y Q; Wu, W J; Xiao, H W; Chen, H B; Zheng, Y; Zhang, Y J; Wang, H X; Huang, L Q

    2013-11-18

    A recently developed revolutionary approach to transcriptomics, RNA-Seq, and suppression subtractive hybridization are powerful tools for gene expression research. However, currently, the difficulty of isolating high-quality RNAs from plant tissues bearing abundant complex polysaccharides, polyphenolics, and secondary metabolites is a serious problem that not only limits the application of these technologies but also hinders studies dealing with RNA in general. We have developed a consistent protocol to prepare highly intact and pure RNAs from tissues of a variety of field-grown plant species, with high yields, in 2 to 3 h. Additionally, this method can be readily applied to mammalian, yeast, and bacterial cells.

  20. The q{sub T} subtraction method for top-quark production at hadron colliders

    Energy Technology Data Exchange (ETDEWEB)

    Bonciani, Roberto [Universita di Roma ' ' La Sapienza' ' , Dipartimento di Fisica, Rome (Italy); INFN, Sezione di Roma, Rome (Italy); Catani, Stefano [INFN, Sezione di Firenze, Sesto Fiorentino, Florence (Italy); Universita di Firenze, Dipartimento di Fisica e Astronomia, Sesto Fiorentino, Florence (Italy); Grazzini, Massimiliano; Sargsyan, Hayk; Torre, Alessandro [Universitaet Zuerich, Physik-Institut, Zurich (Switzerland)

    2015-12-15

    We consider QCD radiative corrections to top-quark pair production at hadron colliders. We use the q{sub T} subtraction formalism to perform a fully differential computation for this process. Our calculation is accurate up to the next-to-leading order in QCD perturbation theory and it includes all the flavour off-diagonal partonic channels at the next-to-next-to-leading order. We present a comparison of our numerical results with those obtained with the publicly available numerical programs MCFM and Top++. (orig.)

  1. Application of the Recursive Subtraction Pulse Shape Analysis algorithm to in-beam HPGe signals

    Energy Technology Data Exchange (ETDEWEB)

    Crespi, F.C.L. [Dipartimento di Fisica, Universita di Milano and INFN Sezione di Milano, Via Celoria 16, 20133 Milano (Italy); Camera, F. [Dipartimento di Fisica, Universita di Milano and INFN Sezione di Milano, Via Celoria 16, 20133 Milano (Italy)], E-mail: camera@mi.infn.it; Bracco, A.; Million, B.; Wieland, O.; Vandone, V. [Dipartimento di Fisica, Universita di Milano and INFN Sezione di Milano, Via Celoria 16, 20133 Milano (Italy); Recchia, F.; Gadea, A.; Kroell, Th. [Laboratori Nazionali di Legnaro, INFN, Viale dell' Universita 2, 35020 Legnaro, Padova (Italy); Mengoni, D.; Farnea, E.; Ur, C.A.; Bazzacco, D. [Dipartimento di Fisica, Universita di Padova and INFN Sezione di Padova, Via Marzolo 8, 35131 Padova (Italy)

    2009-06-11

    The Pulse Shape Analysis algorithm 'Recursive Subtraction' has been applied to data acquired during the in-beam tests of two different highly segmented HPGe detectors. This algorithm processes the net charge signal, determining the number of interactions per segment and their radial coordinates. The RS algorithm performances are evaluated by comparing the results obtained following its application to experimental pulse shapes with those obtained with specific GEANT simulations. Excellent agreement is found between the experimental distribution of the number of interactions per segment and the simulated one. Deviations between experimental radial distribution and the calculated ones are discussed.

  2. Equilibrium radionuclide ventriculography: Comparison with echo-ventriculography and digital subtraction angiocardiography, evaluation of multiparameters

    Energy Technology Data Exchange (ETDEWEB)

    Hoer, G.; Standke, R.; Klepzig, H. Jr.; Maul, F.D.; Tuengerthal, S.; Tezak, S.; Reifarth, N.; Kanemoto, N.; Happ, J.; Baum, R.P.

    1986-09-01

    Subsequent to the discussion of technical prerequisites (fully-automated, reproducible multiparameter-analysis (MPA), rest, exercise) which is followed by remarks concerning the pathophysiology of ischemic left ventricular functional disorders in diastole and systole, the following points are considered: 1) comparative results of RNV, cineventriculoangiography, echo-ventriculography and intraveneous digital subtraction angiocardiography; 2) 'normal' values of RNV in MPA; 3) heart and pulmonary diseases (coronary artery disease with sensitivity and specificity of MPA), chronic obstructive pulmonary disease, chronic aortic insufficiency, hypertension; 4) summary of, and prospects for future potentialities (software, clinical indications).

  3. Analysis of luminosity distributions of strong lensing galaxies: subtraction of diffuse lensed signal

    Science.gov (United States)

    Biernaux, J.; Magain, P.; Hauret, C.

    2017-08-01

    Context. Strong gravitational lensing gives access to the total mass distribution of galaxies. It can unveil a great deal of information about the lenses' dark matter content when combined with the study of the lenses' light profile. However, gravitational lensing galaxies, by definition, appear surrounded by lensed signal, both point-like and diffuse, that is irrelevant to the lens flux. Therefore, the observer is most often restricted to studying the innermost portions of the galaxy, where classical fitting methods show some instabilities. Aims: We aim at subtracting that lensed signal and at characterising some lenses' light profile by computing their shape parameters (half-light radius, ellipticity, and position angle). Our objective is to evaluate the total integrated flux in an aperture the size of the Einstein ring in order to obtain a robust estimate of the quantity of ordinary (luminous) matter in each system. Methods: We are expanding the work we started in a previous paper that consisted in subtracting point-like lensed images and in independently measuring each shape parameter. We improve it by designing a subtraction of the diffuse lensed signal, based only on one simple hypothesis of symmetry. We apply it to the cases where it proves to be necessary. This extra step improves our study of the shape parameters and we refine it even more by upgrading our half-light radius measurement method. We also calculate the impact of our specific image processing on the error bars. Results: The diffuse lensed signal subtraction makes it possible to study a larger portion of relevant galactic flux, as the radius of the fitting region increases by on average 17%. We retrieve new half-light radii values that are on average 11% smaller than in our previous work, although the uncertainties overlap in most cases. This shows that not taking the diffuse lensed signal into account may lead to a significant overestimate of the half-light radius. We are also able to measure

  4. Identification of Differentially Expressed Genes During Ethylene Climacteric of Melon Fruit by Suppression Subtractive Hybridization

    Institute of Scientific and Technical Information of China (English)

    GAO Feng; NIU Yi-ding; HAO Jin-feng; BADE Rengui; ZHANG Li-quan; HASI Agula

    2013-01-01

    Melon (Cucumis melo L.) is an important horticultural crop worldwide. Ethylene regulates the ripening process and affects the ripening rate. To screen genes that are differentially expressed at the burst of ethylene climacteric in melon fruit, we performed suppression subtractive hybridization (SSH) to generate forward and reverse libraries, for which we sequenced 439 and 445 clones, respectively. Our BLAST analysis showed that the genes from the 2 libraries were involved in metabolism, signal transduction, cell structure, transcription, translation, and defense. Six genes were analyzed by qRT-PCR during the differential developmental stage of melon fruit. Our results provide new insight into the understanding of climacteric ripening of melon fruit.

  5. Intravenous digital subtraction angiography in patients with coarctation of the aorta (stenosis of the aortic isthmus)

    Energy Technology Data Exchange (ETDEWEB)

    Rauber, K.; Kollath, J.

    1985-02-01

    The authors report on 18 patients with stenoses of the aortic isthmus in whom digital subtraction angiography had been carried out. In three patients DSA yielded the primary diagnosis of a postductal stenosis of the aortic isthmus. In all postoperative patients, restenosis of the aorta could either be excluded or confirmed. In three cases with complications after an operation, DSA supplied diagnostic information which was decisive for proceeding further. According to the authors' experience, intravenous DSA can replace conventional angiography in the majority of postoperative controls and in future also in primary diagnosis.

  6. Multi-face detection based on downsampling and modified subtractive clustering for color images

    Institute of Scientific and Technical Information of China (English)

    KONG Wan-zeng; ZHU Shan-an

    2007-01-01

    This paper presents a multi-face detection method for color images. The method is based on the assumption that faces are well separated from the background by skin color detection. These faces can be located by the proposed method which modifies the subtractive clustering. The modified clustering algorithm proposes a new definition of distance for multi-face detection, and its key parameters can be predetermined adaptively by statistical information of face objects in the image. Downsampling is employed to reduce the computation of clustering and speed up the process of the proposed method. The effectiveness of the proposed method is illustrated by three experiments.

  7. Thermo Vacuum State for Describing the Density Operator of Photon-subtracted Squeezed Chaotic Light

    Science.gov (United States)

    Wan, Zhi-Long; Fan, Hong-Yi; Li, Heng-Mei; Wang, Zhen

    2017-10-01

    For the density operator describing s-photon-subtracted squeezed chaotic light (PSSCL) we search for its thermo vacuum state (a pure state) in the real-fictitious space. We find that it reduces to a thermo vacuum state of squeezed chaotic light when s = 0, and to a thermo vacuum state of the optical negative binomial field when no squeezing. The new thermo vacuum state simplifies calculating photon number average, quantum fluctuation and Mandel's Q parameter of PSSCL. Using the method of integration within ordered product (IWOP) of operators we also derive the normalization coefficient and explicitly analytical expressions of Wigner function for PSSCL.

  8. Exploiting Rydberg Atom Surface Phonon Polariton Coupling for Single Photon Subtraction

    CERN Document Server

    Kübler, H; Sedlacek, J; Zabawa, P; Shaffer, J P

    2013-01-01

    We investigate a hybrid quantum system that consists of a superatom coupled to a surface phonon-polariton. We apply this hybrid quantum system to subtract individual photons from a beam of light. Rydberg atom blockade is used to attain absorption of a single photon by an atomic microtrap. Surface phonon-polariton coupling to the superatom then triggers the transfer of the excitation to a storage state, a single Rydberg atom. The approach utilizes the interaction between a superatom and a Markovian bath that acts as a controlled decoherence mechanism to irreversibly project the superatom state into a single Rydberg atom state that can be read out.

  9. Subtractive assembly for comparative metagenomics, and its application to type 2 diabetes metagenomes.

    Science.gov (United States)

    Wang, Mingjie; Doak, Thomas G; Ye, Yuzhen

    2015-11-02

    Comparative metagenomics remains challenging due to the size and complexity of metagenomic datasets. Here we introduce subtractive assembly, a de novo assembly approach for comparative metagenomics that directly assembles only the differential reads that distinguish between two groups of metagenomes. Using simulated datasets, we show it improves both the efficiency of the assembly and the assembly quality of the differential genomes and genes. Further, its application to type 2 diabetes (T2D) metagenomic datasets reveals clear signatures of the T2D gut microbiome, revealing new phylogenetic and functional features of the gut microbial communities associated with T2D.

  10. A symmetrical subtraction combined with interpolated values for eliminating scattering from fluorescence EEM data

    Science.gov (United States)

    Xu, Jing; Liu, Xiaofei; Wang, Yutian

    2016-08-01

    Parallel factor analysis is a widely used method to extract qualitative and quantitative information of the analyte of interest from fluorescence emission-excitation matrix containing unknown components. Big amplitude of scattering will influence the results of parallel factor analysis. Many methods of eliminating scattering have been proposed. Each of these methods has its advantages and disadvantages. The combination of symmetrical subtraction and interpolated values has been discussed. The combination refers to both the combination of results and the combination of methods. Nine methods were used for comparison. The results show the combination of results can make a better concentration prediction for all the components.

  11. Subtraction of test mass angular noise in the LISA Technology Package interferometer

    CERN Document Server

    Cervantes, Felipe Guzmán; Wanner, Gudrun; Heinzel, Gerhard; Danzmann, Karsten

    2012-01-01

    We present recent sensitivity measurements of the LISA Technology Package interferometer with articulated mirrors as test masses, actuated by piezo-electric transducers. The required longitudinal displacement resolution of 9 pm/sqrt[Hz] above 3 mHz has been demonstrated with an angular noise that corresponds to the expected in on-orbit operation. The excess noise contribution of this test mass jitter onto the sensitive displacement readout was completely subtracted by fitting the angular interferometric data streams to the longitudinal displacement measurement. Thus, this cross-coupling constitutes no limitation to the required performance of the LISA Technology Package interferometry.

  12. Accelerated parabolic Radon domain 2D adaptive multiple subtraction with fast iterative shrinkage thresholding algorithm and its application in parabolic Radon domain hybrid demultiple method

    Science.gov (United States)

    Li, Zhong-xiao; Li, Zhen-chun

    2017-08-01

    Adaptive multiple subtraction is an important step for successfully conducting surface-related multiple elimination in marine seismic exploration. 2D adaptive multiple subtraction conducted in the parabolic Radon domain has been proposed to better separate primaries and multiples than 2D adaptive multiple subtraction conducted in the time-offset domain. Additionally, the parabolic Radon domain hybrid demultiple method combining parabolic Radon filtering and parabolic Radon domain 2D adaptive multiple subtraction can better remove multiples than the cascaded demultiple method using time-offset domain 2D adaptive multiple subtraction and the parabolic Radon transform method sequentially. To solve the matching filter in the optimization problem with L1 norm minimization constraint of primaries, traditional parabolic Radon domain 2D adaptive multiple subtraction uses the iterative reweighted least squares (IRLS) algorithm, which is computationally expensive for solving a weighted LS inversion in each iteration. In this paper we introduce the fast iterative shrinkage thresholding algorithm (FISTA) as a faster alternative to the IRLS algorithm for parabolic Radon domain 2D adaptive multiple subtraction. FISTA uses the shrinkage-thresholding operator to promote the sparsity of estimated primaries and solves the 2D matching filter with iterative steps. FISTA based parabolic Radon domain 2D adaptive multiple subtraction reduces the computation time effectively while achieving similar accuracy compared with IRLS based parabolic Radon domain 2D adaptive multiple subtraction. Additionally, the provided examples show that FISTA based parabolic Radon domain 2D adaptive multiple subtraction can better separate primaries and multiples than FISTA based time-offset domain 2D adaptive multiple subtraction. Furthermore, we introduce FISTA based parabolic Radon domain 2D adaptive multiple subtraction into the parabolic Radon domain hybrid demultiple method to improve its computation

  13. Comparative transcripts profiling of fruit mesocarp and endocarp relevant to secondary metabolism by suppression subtractive hybridization in Azadirachta indica (neem).

    Science.gov (United States)

    Narnoliya, Lokesh K; Rajakani, Raja; Sangwan, Neelam S; Gupta, Vikrant; Sangwan, Rajender S

    2014-05-01

    Azadirachta indica (neem) is a medicinally important plant that is valued for its bioactive secondary metabolites. Higher levels of the bioactive phytochemicals are accumulated in fruits than in other tissues. In the present study, a total of 387 and 512 ESTs, respectively, from endocarp and mesocarp of neem fruits were isolated and analyzed. Out of them 318 ESTs (82.17%) clones from endocarp and 418 ESTs (81.64%) from mesocarp encoded putative proteins that could be classified into three major gene ontology categories: biological process, molecular function and cellular component. From the analyses of contigs, 73 unigenes from the forward subtracted library and 35 unigenes from the reverse subtracted library were obtained. The ESTs from mesocarp encoded cytochrome P450 enzymes, which indicated hydroxylation to be a major metabolic event and that biogeneration of hydroxylated neem fruit phytochemicals was differentially regulated with developmental stage-specificity of synthesis. Through this study, we present the first report of any gene expression data in neem tissues. Neem hydroxy-methyl glutaryl-coenzyme A reductase (NHMGR) gene was used as expressing control vis-a-vis subtracted tissues. NHMGR was present in fruit, endocarp and mesocarp tissues, but absent in subtractive libraries, revealing that it was successfully eliminated during subtraction. Eight genes of interest from subtracted libraries were profiled for their expression in fruit, mesocarp and endocarp. Expression profiles validated the quality of the libraries and functional diversity of the tissues. The subtractive cDNA library and EST database described in this study represent a valuable transcript sequence resource for future research aimed at improving the economically important medicinal plant.

  14. Accuracy of digital subtraction radiography in combination with a contrast media in assessment of proximal caries depth

    Directory of Open Access Journals (Sweden)

    Farzad Esmaeili

    2008-07-01

    Full Text Available Background and aims. Radiography is used to diagnose the demineralization process and carious lesions; however, conventional radiography and direct digital images do not show these lesions when the amount of demineralization is less than 40%. Digital subtraction radiography has recently been used to improve the diagnostic quality of these lesions. The purpose of this study was to compare the caries depth estimated by digital subtraction radiography in combination with barium sulfate in diagnosing proximal dental caries with histopathologic evaluation. Materials and methods. In this study 30 molars and premolars (24 demineralized lesions with cavity, 8 without cavity were studied. Direct digital images were taken (kVp: 68, mA: 8; t: 0.12 for premolars and t: 0.16 for molars whereas the position of X-ray tube and CCD receptor and teeth was fixed. To prepare the second images 135 gr/L barium sulfate was used. The images obtained with the same exposure and geometry and then subtracted. The depth of the lesions in direct digital and subtracted images were assessed and compared with the depth measured in histopathologic assessments. Results. The mean depths (± SD of the lesions were 1.80 ± 0.77 mm in direct digital radiography, 2.32 ± 0.76 mm in subtracted images after barium sulfate treatment, and 2.51 ± 0.43 mm in histopathologic sections. The statistical difference between direct digital radiography and the other methods was significant (P < 0.05. However, the differences were not statistically significant between subtracted images and histopathologic sections. The average intra-class correlation coefficient was 0.7241 (CI: 95%. Conclusion. The present study has demonstrated that digital subtraction radiography images have the potential to measure the depth of proximal caries with no significant difference with histopathologic evaluation.

  15. Nonenhanced peripheral MR-angiography (MRA) at 3 Tesla: evaluation of quiescent-interval single-shot MRA in patients undergoing digital subtraction angiography.

    Science.gov (United States)

    Wagner, Moritz; Knobloch, Gesine; Gielen, Martin; Lauff, Marie-Teres; Romano, Valentina; Hamm, Bernd; Kröncke, Thomas

    2015-04-01

    Quiescent-interval single-shot MRA (QISS-MRA) is a promising nonenhanced imaging technique for assessment of peripheral arterial disease (PAD). Previous studies at 3 Tesla included only very limited numbers of patients for correlation of QISS-MRA with digital subtraction angiography (DSA) as standard of reference (SOR). The aim of this prospective institutional review board-approved study was to compare QISS-MRA at 3 Tesla with DSA in a larger patient group. Our study included 32 consecutive patients who underwent QISS-MRA, contrast-enhanced MRA (CE-MRA), and DSA. Two readers independently performed a per-segment evaluation of QISS-MRA and CE-MRA for image quality and identification of non-significant stenosis (Tesla showed similar diagnostic accuracy in the assessment of PAD. A limitation of QISS-MRA was the lower rate of assessable vessel segments compared to CE-MRA.

  16. Value of automatic bone subtraction in cranial CT angiography: comparison of bone-subtracted vs. standard CT angiography in 100 patients

    Energy Technology Data Exchange (ETDEWEB)

    Morhard, Dominik; Fink, Christian; Becker, Christoph; Reiser, Maximilian F.; Nikolaou, Konstantin [Ludwig-Maximilians-University of Munich, Institute of Clinical Radiology, Munich (Germany)

    2008-05-15

    Non-contrast-enhanced cranial computed tomography (NECT) and CT angiography (CTA) are the most frequently used modalities in the triage of patients with acute ischemic and hemorrhagic stroke. CTA bone removal can improve the delineation of vasculature closely adjacent to bony structures, which is sometimes limited in standard CTA. The aim of this study was the evaluation of the clinical benefit of bone subtraction (BS) regarding delineation of cerebral vasculature, reading time and depiction of vascular pathologies compared to standard CTA without BS. A total of 100 patients who underwent NECT and supraaortic CTA on a 64-slice CT system were retrospectively included in the study. Bone removal was performed by subtraction of the NECT data from the CTA data using a dedicated workstation. Standard and BS CTA of each patient was reviewed for delineation of cerebral vasculature (grading scale from 1 = 'excellent delineation' to 10 = 'hardly any delineation'), reading time and depiction of vascular pathologies (standardized catalog) by two blinded readers. For BS data sets, the quality of BS was rated by a combination of the criteria complete bone removal, depiction of vascular structures and sufficient quality for diagnostic evaluation. The use of BS significantly reduced reading time from 4.60 min to 3.49 min (p < 0.001). Performing BS, the quality of vascular delineation of the cerebral arteries, cerebral veins and cavernous segment of the ICA increased significantly as compared to standard CTA (1.70 vs. 2.70; 2.60 vs. 4.12; 2.35 vs. 4.40, all p < 0.001). Consensus reading showed 41 pathologies in 35 patients. Diagnosis was missed or wrong overall in 15 cases, with 3 missed aneurysms (CTA: 2 vs. BS: 1), 8 wrong stenotic findings (CTA: 3 vs. BS: 5) and 4 missed partial thromboses (CTA: 2 vs. BS: 2). Performing BS in supraaortic CTA for the evaluation of cerebral vasculature reduces reading time and improves delineation of vessels. Diagnostic

  17. 泥鳅抑制性消减DNA文库的构建及质量分析%Construction and Quality Analysis of Suppression Subtracted DNA Library of Misgurnus anguillicaudatus

    Institute of Scientific and Technical Information of China (English)

    夏晓华; 仉晓文; 张林霞; 王莉娜; 常重杰

    2012-01-01

    In order to provide a basis for screening and cloning the gender-specific genes, the genomic DNA library was constructed by suppression subtractive hybridization (SSH) technique taking M. anguillicaudatus as experimental materials. And blue-white blot and PCR were used to detect the subtracted DNA library quality. The results showed that the forward and reverse suppression subtracted genomic DNA library was successfully constructed, the forward library contained 240 clones and 216 clones in the reverse library, the positive ratio of constructed genomic DNA libraries was 95. 61 % and the length of DNA fragments ranged from 0. 2 to 1. 0 kp.%为筛选、克隆泥鳅性别特异基因奠定基础,以黄河中下游雌性和雄性成体泥鳅为材料,采用抑制性消减杂交技术(SSH)构建基因组DNA文库,并结合蓝白斑筛选和PCR方法鉴定文库质量.结果表明:雌雄泥鳅基因组DNA的正反向抑制消减文库构建成功,其中,正向文库包含240个克隆,反向文库包含216个克隆,阳性克隆率为95.61%,插入片段范围为0.2~1.0 kb.

  18. [Correction of kyphotic deformity of the cervical spine in ankylosing spondylitis using pedicle subtraction osteotomy of the seventh cervical vertebra].

    Science.gov (United States)

    Vaněk, P; Votavová, M; Ostrý, S; Beneš, V; Pavelka, K

    2014-01-01

    The aim of the study is to present the technique of pedicle subtraction osteotomy (PSO) of the seventh cervical vertebra (C7) for correction of rigid kyphotic deformity of the cervicothoracic junction (C/Th) in patients with severe ankylosing spondylitis (AS).. The PSO technique for correction of rigid deformity of the C/Th spine was used in five patients with the aim to restore their ability of horizontal vision. The follow-up in all patients lasted two years at least. Clinical assessment of treatment results was based on the patients' neurological status and their satisfaction with the correction achieved. Improvement in a vertical 2) line of sight was evaluated using the angle measured between the forehead-chin line and the vertical (FCv angle) in a lateral view photograph of the standing patient. The achieved correction of kyphotic deformity was assessed by comparing the pre-operative Cobb's angle between the second cervical and the fourth thoracic vertebra with the post-operative one. The average operative time was 4 hours (range, 3.5 to 5 h). The average blood loss was 1600 ml (range, 800 to 2100 ml). On the average, the FCv angle was reduced by 45.2° and Cobb's angle was corrected) by 54.6°. All patients were satisfied with the degree of correction achieved and reported alleviation of neck pain. none of the patients showed any significant loss of correction or neurological deterioration at two-year follow-up. The theoretical and technical principles of corrective osteotomy at the C7 level performed for rigid kyphotic deformity of the spine at the C/Th junction are presented in our group of patients. Our results give support to the superiority of instrumented PSO used currently over the previous techniques. In accordance with the relevant literature data, attention is drawn to a relatively higher risk of this procedure in comparison with corrective surgery performed at the other spinal levels. Corrective osteotomy of a rigid kyphotic deformity at the C

  19. Follow-up after embolization of ruptured intracranial aneurysms: A prospective comparison of two-dimensional digital subtraction angiography, three-dimensional digital subtraction angiography, and time-of-flight magnetic resonance angiography

    Energy Technology Data Exchange (ETDEWEB)

    Serafin, Zbigniew; Strzesniewski, Piotr; Lasek, Wladyslaw [Nicolaus Copernicus University, Collegium Medicum, Department of Radiology and Diagnostic Imaging, Bydgoszcz (Poland); Beuth, Wojciech [Nicolaus Copernicus University, Collegium Medicum, Department of Neurosurgery and Neurotraumatology, Bydgoszcz (Poland)

    2012-11-15

    To prospectively compare of the diagnostic value of digital subtraction angiography (DSA) and time-of-flight magnetic resonance angiography (TOF-MRA) in the follow-up of intracranial aneurysms after endovascular treatment. Seventy-two consecutive patients were examined 3 months after the embolization. The index tests included: two-dimensional DSA (2D-DSA), three-dimensional DSA (3D-DSA), and TOF-MRA. The reference test was a retrospective consensus between 2D-DSA images, 3D-DSA images, and source rotational DSA images. The evaluation included: detection of the residual flow, quantification of the flow, and validity of the decision regarding retreatment. Intraobserver agreement and interobserver agreement were determined. The sensitivity and specificity of residual flow detection ranged from 84.6 % (2D-DSA and TOF-MRA) to 92.3 % (3D-DSA) and from 91.3 % (TOF-MRA) to 97.8 % (3D-DSA), respectively. The accuracy of occlusion degree evaluation ranged from 0.78 (2D-DSA) to 0.92 (3D-DSA, Cohen's kappa). The 2D-DSA method presented lower performance in the decision on retreatment than 3D-DSA (P < 0.05, ROC analysis). The intraobserver agreement was very good for all techniques ({kappa} = 0.80-0.97). The interobserver agreement was moderate for TOF-MRA and very good for 2D-DSA and 3D-DSA ({kappa} = 0.72-0.94). Considering the invasiveness of DSA and the minor difference in the diagnostic performance between 3D-DSA and TOF-MRA, the latter method should be the first-line modality for follow-up after aneurysm embolization. (orig.)

  20. Identification of differentially expressed genes in rat silicosis model by suppression subtractive hybridization analysis

    Institute of Scientific and Technical Information of China (English)

    Zhongyuan Jin; Chunyan Fu; Jifang Wen; Baoan Liu; Deyun Feng; Chen Chen; Xiang Li; Yongbin Hu; Jinwu Peng; Yu Liu; Jing Du

    2008-01-01

    The critical molecular mechanism in the development of the pulmonary fibrosis remains unknown, leaving diagnosed patients with a poor prognosis. To isolate the genes specifi-cally up-regulated in pulmonary fibrosis, we established a rat silicosis model 360 d after treatment with crystalline silica suspension. Radiographs of chests showed that some scattered high-density shadows appeared in the lung field.Typical microscopic fibrosing silicotic nodules formed in the lung,alveolar epithelial cells and bronchial epithelial cells,particularly around the partial fibrosing silicotic nodules;some of them showed atypical hyperplasia that suggested a correlation between silicosis and lung cancer.Suppression subtractive hybridization analysis was performed to compare gene expression in lung tissue with silicosis and normal lung tissue.Reverse transcription-polymerase chain rection showed that the expressions of seven novel cDNA sequences identified by suppression subtractive hybridization in lung tissue with silicosis differed from normal lung tissue. Bioinformatics analysis showed that 47 positive clones rep-resented 35 genes containing two putative proteins and four predicted similar proteins.The analysis also showed that some screened genes in silicosis,such as prolyl 4-hydroxylases,actin-related protein-2/3 complex and acidic mammalian chitinase,have not been previously reported.These genes may provide new clues for investigating the molecular mechanisms in the development of pulmonary fibrosis.

  1. Cooperative Moving Object Segmentation using Two Cameras based on Background Subtraction and Image Registration

    Directory of Open Access Journals (Sweden)

    Zhigao Cui

    2014-03-01

    Full Text Available Moving camera, such as PTZ (pan-tilt-zoom camera, has been widely applied in visual surveillance system. However, it’s difficult to extract moving objects because of the dynamic background caused by the camera motion. In this paper, a novel framework for moving object segmentation exploiting two cameras collaboration is presented by combining background subtraction and image registration method. The proposed method uses one static camera to capture large-view images at low resolution, and one moving camera (i.e. PTZ camera to capture local-view images at high resolution. Different with methods using a single moving camera, the moving objects can be effectively segmented in the static camera image by background subtraction method. Then image registration method can be applied to extract moving region in the moving camera image. To deal with the resolution and intensity discrepancy between two synchronized images, we design a practical three-step image registration method, which has higher registration accuracy than traditional feature based method. Experimental results on outdoor scene demonstrate the effectiveness and robustness of proposed approach.

  2. [Galaxy spectrum subtraction of a mixed spectrum based on two class PCA eigen-spectra].

    Science.gov (United States)

    Tu, Liang-Ping; Wu, Fu-Chao; Luo, A-Li; Zhao, Yong-Heng

    2010-06-01

    The authors present a new method called two class PCA for decomposing the mixed spectra, namely, for subtracting the host galaxy contamination from each SN spectrum. The authors improved the quality of reconstructed galaxy spectrum and computational efficiency, and these improvements were realized because we used both the PCA eigen spectra of galaxy templates library and SN templates library to model the mixed spectrum. The method includes mainly three steps described as follows. The first step is calculating two class PCA eigen spectra of galaxy templates and SN templates respectively. The second step is determining all reconstructed coefficients by the SVD matrix decomposition or orthogonal transformation. And the third step is computing a reconstructed galaxy spectrum and subtracting it from each mixed spectrum. Experiments show that this method can obtain an accurate decomposition of a mixed synthetic spectrum, and is a method with low time-consumption to get the reliable SN spectrum without galaxy contamination and can be used for spectral analysis of large amount of spectra. The time consumption using our method is much lower than that using chi2-template fitting for a spectrum.

  3. Technetium-99m-sestamibi/pertechnetate subtraction scintigraphy vs ultrasonography for preoperative localization in primary hyperparathyroidism

    Energy Technology Data Exchange (ETDEWEB)

    Berczi, C.; Lukacs, G.; Balazs, G. [Department of Surgery, University of Debrecen (Hungary); Mezosi, E.; Bajnok, L. [1. Department of Internal Medicine, University of Debrecen (Hungary); Galuska, L.; Varga, J. [Department of Nuclear Medicine, University of Debrecen (Hungary)

    2002-03-01

    A prospective study was performed to evaluate the efficacy of technetium-99m-sestamibi and technetium-99m-pertechnetate subtraction scanning and US for imaging parathyroid glands in primary hyperparathyroidism. Sixty-three patients were surgically treated for primary hyperparathyroidism (HPT). Preoperative scintigraphy and US were performed in all cases. Bilateral neck exploration was carried out on each patient. Results of radionuclide studies and US were compared with surgical and histological findings. In 57 patients with primary HPT the radionuclide scanning gave true-positive results. Four false-negative and two false-positive scintigrams were obtained. The sensitivity and the positive predictive value (PPV) of scintigraphy were 93 and 97%, respectively. Forty-one cases were correctly localized by the US. Seventeen US results were false negative and five were false positive. The sensitivity and the PPV for US were 71 and 89%, respectively. There was a statistically significant difference between the sensitivity of the scintigraphy compared with the US (p=0.001). Sensitivities of radionuclide scans and US were higher for adenomas (100 and 83%) than for hyperplastic glands (75 and 40%). The sensitivity of technetium-99m-sestamibi and technetium-99m-pertechnetate subtraction scintigraphy was significantly higher compared with US. This sensitive method could help surgeons in performing a rapid and directed parathyroidectomy. (orig.)

  4. Clinical use of the ABO-Scoring Index: reliability and subtraction frequency.

    Science.gov (United States)

    Lieber, William S; Carlson, Sean K; Baumrind, Sheldon; Poulton, Donald R

    2003-10-01

    This study tested the reliability and subtraction frequency of the study model-scoring system of the American Board of Orthodontists (ABO). We used a sample of 36 posttreatment study models that were selected randomly from six different orthodontic offices. Intrajudge and interjudge reliability was calculated using nonparametric statistics (Spearman rank coefficient, Wilcoxon, Kruskal-Wallis, and Mann-Whitney tests). We found differences ranging from 3 to 6 subtraction points (total score) for intrajudge scoring between two sessions. For overall total ABO score, the average correlation was .77. Intrajudge correlation was greatest for occlusal relationships and least for interproximal contacts. Interjudge correlation for ABO score averaged r = .85. Correlation was greatest for buccolingual inclination and least for overjet. The data show that some judges, on average, were much more lenient than others and that this resulted in a range of total scores between 19.7 and 27.5. Most of the deductions were found in the buccal segments and most were related to the second molars. We present these findings in the context of clinicians preparing for the ABO phase III examination and for orthodontists in their ongoing evaluation of clinical results.

  5. Identification of cold tolerance genes from leaves of mangrove plant Kandelia obovata by suppression subtractive hybridization.

    Science.gov (United States)

    Fei, Jiao; Wang, You-Shao; Jiang, Zhao-Yu; Cheng, Hao; Zhang, Jian-Dong

    2015-10-01

    Low temperature is a major abiotic stress that seriously limits mangrove productivity and distribution, the molecular mechanisms of cold tolerance involved in mangroves are still poorly understood at present. It was used to identify the potential cold-related genes in Kandelia obovata (K. obovata) by suppression subtractive hybridization. 334 cold-related expressed sequence tags (ESTs) out of 670 clones were isolated and sequenced. Among these ESTs, 143 unique cDNAs were identified and classified into ten groups, such as metabolism, energy, cell rescue and defense, transcription and photosynthesis according to NCBI blast. Based on bioinformatics analysis, these ESTs were mainly related to response to stimulus and metabolic process, and were included to 72 KEGG pathways. Two selected genes (e.g., aquaporin gene and zinc family protein gene) from the library were further analyzed by quantitative real-time PCR analysis. Both the two genes were found to be transcriptionally up-regulated under cold stress, which partly approve the construction of the subtractive cDNA library. The diversity of the putative functions of these genes indicated that cold stress resulted in a complex response in K. obovata. Further investigation on the functions and potential pathways of these genes will facilitate the understanding of the molecular adaptations to cold tolerance in mangrove plants.

  6. Identification of cadmium-induced Agaricus blazei genes through suppression subtractive hybridization.

    Science.gov (United States)

    Wang, Liling; Li, Haibo; Wei, Hailong; Wu, Xueqian; Ke, Leqin

    2014-01-01

    Cadmium (Cd) is one of the most serious environmental pollutants. Filamentous fungi are very promising organisms for controlling and reducing the amount of heavy metals released by human and industrial activities. However, the molecular mechanisms involved in Cd accumulation and tolerance of filamentous fungi are not fully understood. Agaricus blazei Murrill, an edible mushroom with medicinal properties, demonstrates high tolerance for heavy metals, especially Cd. To investigate the molecular mechanisms underlying the response of A. blazei after Cd exposure, we constructed a forward subtractive library that represents cadmium-induced genes in A. blazei under 4 ppm Cd stress for 14 days using suppression subtractive hybridization combined with mirror orientation selection. Differential screening allowed us to identify 39 upregulated genes, 26 of which are involved in metabolism, protein fate, cellular transport, transport facilitation and transport routes, cell rescue, defense and virulence, transcription, and the action of proteins with a binding function, and 13 are encoding hypothetical proteins with unknown functions. Induction of six A. blazei genes after Cd exposure was further confirmed by RT-qPCR. The cDNAs isolated in this study contribute to our understanding of genes involved in the biochemical pathways that participate in the response of filamentous fungi to Cd exposure.

  7. Isolation of differentially expressed sex genes in garden asparagus using suppression subtractive hybridization.

    Science.gov (United States)

    Deng, Chuan-liang; Wang, Ning-na; Li, Shu-fen; Dong, Tian-yu; Zhao, Xin-peng; Wang, Shao-jing; Gao, Wu-jun; Lu, Long-dou

    2015-09-01

    Garden asparagus (Asparagus officinalis L.) is a dioecious species whose male and female flowers are found in separate unisexual individuals. A region called the M-locus, located on a pair of homomorphic sex chromosomes, controls sexual dimorphism in asparagus. To date, no sex determining gene has been isolated from asparagus. To identify more genes involved in flower development in asparagus, subtractive hybridization library of male flowers in asparagus was constructed by suppression subtraction hybridization. A total of 107 expressed sequence tags (ESTs) were identified. BLASTX analysis showed that the library contained several genes that could be related to flower development. The expression patterns of seven selected genes believed to be involved in the development of asparagus male flower were further analyzed by semi-quantitative or real-time reverse-transcription polymerase chain reaction (RT-PCR). Results showed that AOEST4-5, AOEST12-40, and AOEST13-38 were strongly expressed in the male flower stage, whereas no transcript level of AOEST13-38 was detected in the female flower stage. The expression levels of AOEST13-87, AOEST13-92, AOEST13-40, and AOEST18-87 in the male flower stage were also higher than those in the female flower stage, although these transcripts were also expressed in other tissues. The identified genes can provide a strong starting point for further studies on the underlying molecular differences between the male and female flowers of asparagus.

  8. Background Subtraction and Frame Difference Based Moving Obiect Detection for Real-Time Surveillance

    Institute of Scientific and Technical Information of China (English)

    黄中文; 戚飞虎; 岑峰

    2003-01-01

    A new real-time algorithm is proposed in this paper for detecting moving object in color image sequences taken from stationary cameras. This algorithm combines a temporal difference with an adaptive background subtraction where the combination is novel. When changes occur, the background is automatically adapted to suit the new conditions. For the background model, a new model is proposed with each frame decomposed into regions and the model is based not only upon single pixel but also on the characteristic of a region. The hybrid presentation includes a model for single pixel information and a model for the pixel's neighboring area information.This new model of background can both improve the accuracy of segmentation due to that spatial information is taken into account and saliently speed up the processing procedure because portion of neighboring pixel can be selected into modeling. The algorithm was successfully used in a video surveillance system and the experiment result shows it can obtain a clearer foreground than the single frame difference or background subtraction method.

  9. Development of pooled suppression subtractive hybridization to analyze the pangenome of Staphylococcus aureus.

    Science.gov (United States)

    Gerrish, Robert S; Gill, Ann L; Fowler, Vance G; Gill, Steven R

    2010-04-01

    We describe the development and application of a Pooled Suppression Subtractive Hybridization (PSSH) method to describe differences between the genomic content of a pool of clinical Staphylococcus aureus isolates and a sequenced reference strain. In comparative bacterial genomics, Suppression Subtractive Hybridization (SSH) is normally utilized to compare genomic features or expression profiles of one strain versus another, which limits its ability to analyze communities of isolates. However, a PSSH approach theoretically enables the user to characterize the entirety of gene content unique to a related group of isolates in a single reaction. These unique fragments may then be linked to individual isolates through standard PCR. This method was applied to examine the genomic diversity found in pools of S.aureus isolates associated with complicated bacteremia infections leading to endocarditis and osteomyelitis. Across four pools of 10 isolates each, four hundred and twenty seven fragments not found in or significantly divergent from the S. aureus NCTC 8325 reference genome were detected. These fragments could be linked to individual strains within its pool by PCR. This is the first use of PSSH to examine the S. aureus pangenome. We propose that PSSH is a powerful tool for researchers interested in rapidly comparing the genomic content of multiple unstudied isolates.

  10. The IPAC Image Subtraction and Discovery Pipeline for the intermediate Palomar Transient Factory

    CERN Document Server

    Masci, Frank; Rebbapragada, Umaa; Doran, Gary; Miller, Adam; Bell, Eric; Kasliwal, Mansi; Ofek, Eran; Surace, Jason; Shupe, David; Grillmair, Carl; Jackson, Ed; Barlow, Tom; Yan, Lin; Cao, Yi; Cenko, S Bradley; Storrie-Lombardi, Lisa; Helou, George; Prince, Thomas; Kulkarni, Shrinivas

    2016-01-01

    We describe the near real-time transient-source discovery engine for the intermediate Palomar Transient Factory (iPTF), currently in operations at the Infrared Processing and Analysis Center (IPAC), Caltech. We coin this system the IPAC/iPTF Discovery Engine (or IDE). We review the algorithms used for PSF-matching, image subtraction, detection, photometry, and machine-learned (ML) vetting of extracted transient candidates. We also review the performance of our ML classifier. For a limiting signal-to-noise ratio of 4 in relatively unconfused regions, "bogus" candidates from processing artifacts and imperfect image subtractions outnumber real transients by ~ 10:1. This can be considerably higher for image data with inaccurate astrometric and/or PSF-matching solutions. Despite this occasionally high contamination rate, the ML classifier is able to identify real transients with an efficiency (or completeness) of ~ 97% for a maximum tolerable false-positive rate of 1% when classifying raw candidates. All subtracti...

  11. Comparison of the diagnostic accuracy of direct digital radiography system, filtered images, and subtraction radiography

    Directory of Open Access Journals (Sweden)

    Wilton Mitsunari Takeshita

    2013-01-01

    Full Text Available Background: To compare the diagnostic accuracy of three different imaging systems: Direct digital radiography system (DDR-CMOS, four types of filtered images, and a priori and a posteriori registration of digital subtraction radiography (DSR in the diagnosis of proximal defects. Materials and Methods: The teeth were arranged in pairs in 10 blocks of vinyl polysiloxane, and proximal defects were performed with drills of 0.25, 0.5, and 1 mm diameter. Kodak RVG 6100 sensor was used to capture the images. A posteriori DSR registrations were done with Regeemy 0.2.43 and subtraction with Image Tool 3.0. Filtered images were obtained with Kodak Dental Imaging 6.1 software. Images (n = 360 were evaluated by three raters, all experts in dental radiology. Results: Sensitivity and specificity of the area under the receiver operator characteristic (ROC curve (Az were higher for DSR images with all three drills (Az = 0.896, 0.979, and 1.000 for drills 0.25, 0.5, and 1 mm, respectively. The highest values were found for 1-mm drills and the lowest for 0.25-mm drills, with negative filter having the lowest values of all (Az = 0.631. Conclusion: The best method of diagnosis was by using a DSR. The negative filter obtained the worst results. Larger drills showed the highest sensitivity and specificity values of the area under the ROC curve.

  12. [Construction and analysis of subtractive cDNA library of Phellodendron amurense under drought stress].

    Science.gov (United States)

    Wang, Huimei; Wang, Yanbing; Zu, Yuangang; Sun, Lianhui

    2008-02-01

    With cDNA from Phellodendron amurense seedlings treated with drought stress as tester and cDNA from this plant in normal growth as driver, we construct cDNA subtracted library using suppression subtractive hybridization (SSH). In the library, the rate of recombination was 95%, the size of inserts was 300-800 bp. Two hundred and sixty-five new genes were obtained by DNA sequencing 816 positive clones picked randomly, and partitioned to 16 classes after nucleotide Blast and BlastX homological analysis against NT, NR, SWISSPROT, KEGG database. Forty-four drought stress associated genes, such as heat shock protein cognate 70, dehydration responsive protein 22, universal stress protein, metallothionein II, late embryogenesis abundant protein, were obtained, which made 16.6% of the overall genes. These genes included osmotic regulator, signal component regulatory protein and antioxidant enzyme. The research had established a basis for cloning stress resistance genes and further studying genes expression in P. amurense seedlings under drought stress.

  13. Analysis of gene expression in granulosa cells of ovine antral growing follicles using suppressive subtractive hybridization.

    Science.gov (United States)

    Chen, A Qin; Wang, Zheng Guang; Xu, Zi Rong; Yu, Song Dong; Yang, Zhi Gang

    2009-10-01

    Follicular growth, development and ovulation are highly ordered processes that involve the expression of many genes under precise temporal and spatial regulation. However, information on stage-specific gene expression during the antral follicle phase in sheep is not well understood. In the present study, suppressive subtractive hybridization (SSH) was performed to screen genes that were differentially expressed in the granulosa cells between large follicles (LF, >5mm) and small follicles (SF, 3-5mm), and subtractive cDNA library was constructed. Furthermore, with dot-blot analysis, a total of 90 clones randomly selected from the library were proven to be differentially expressed in the granulosa cells. Among these, 38 exhibited high homology to known genes, 14 sequences were corresponding to novel expressed sequence tags (ESTs). Four ESTs, LAPTM4A, SERPINE2, GSTA1, and INHBA, were further examined the reproducibility of the SSH data by the real-time quantitative PCR. Results confirmed an increase expression of respective mRNA in granulosa cells of large follicles compared with that of small follicles. It is concluded that we have identified several genes (known or unknown) that may effect follicular growth, dominance or ovulation in ewes.

  14. Increasing LIGO sensitivity by feedforward subtraction of auxiliary length control noise

    Science.gov (United States)

    Meadors, Grant; Kawabe, Keita; Riles, Keith

    2013-04-01

    LIGO, the Laser Interferometer Gravitational-wave Observatory [Hanford, Washington and Livingston, Louisiana] measures the differential length of 4-km Michelson arms with Fabry-Perot cavities. Length changes could indicate strain caused by astrophysical sources of gravitational waves. Fundamentally limited by seismic noise, thermal suspension noise, and laser shot noise in different frequency bands, a LIGO interferometer's sensitivity can also be degraded by additional relative motion of the inner arm cavity mirrors due to imperfectly-servoed Michelson motion. In this project we seek to subtract the effects of this residual motion by feedforward correction of the gravitational-wave data channel. We divide data from LIGO's sixth science run into 1024-second time windows and numerically fit a filter representing the frequency-domain transfer function from Michelson servo noise to gravitational wave channel for each window. Finally, the Michelson servo channel is processed through the filter and is subtracted from the gravitational-wave signal channel. The algorithm used in this procedure will be described with a preliminary assessment of the achievable sensitivity improvement.

  15. A System based on Adaptive Background Subtraction Approach for Moving Object Detection and Tracking in Videos

    Directory of Open Access Journals (Sweden)

    Bahadır KARASULU

    2013-04-01

    Full Text Available Video surveillance systems are based on video and image processing research areas in the scope of computer science. Video processing covers various methods which are used to browse the changes in existing scene for specific video. Nowadays, video processing is one of the important areas of computer science. Two-dimensional videos are used to apply various segmentation and object detection and tracking processes which exists in multimedia content-based indexing, information retrieval, visual and distributed cross-camera surveillance systems, people tracking, traffic tracking and similar applications. Background subtraction (BS approach is a frequently used method for moving object detection and tracking. In the literature, there exist similar methods for this issue. In this research study, it is proposed to provide a more efficient method which is an addition to existing methods. According to model which is produced by using adaptive background subtraction (ABS, an object detection and tracking system’s software is implemented in computer environment. The performance of developed system is tested via experimental works with related video datasets. The experimental results and discussion are given in the study

  16. Differential subtraction display: a unified approach for isolation of cDNAs from differentially expressed genes.

    Science.gov (United States)

    Pardinas, J R; Combates, N J; Prouty, S M; Stenn, K S; Parimoo, S

    1998-03-15

    We have developed a novel efficient approach, termed differential subtraction display, for the identification of differentially expressed genes. Several critical parameters for the reproducibility and enhanced sensitivity of display, as well as steps to reduce the number of false positive cDNA species, have been defined. These include- (a) use of standardized oligo(dT)-primed cDNA pools rather than total RNA as the starting material for differential display, (b) critical role of optimal cDNA input for each distinct class of primers, (c) phenomena of primer dominance and interference, and (d) design of a novel set of enhanced specificity anchor primers. Introduction of an efficient subtractive hybridization step prior to cloning of cDNA species enriches the bona fide cDNA species that are either exclusively present in one sample (+/-) or show altered expression (up-/down-regulation) in RNA samples from two different tissues or cell types. This approach, in comparison to differential display, has several advantages in terms of reproducibility and enhanced sensitivity of display coupled to the cloning of enriched bona fide cDNA species corresponding to differentially expressed RNAs.

  17. A Robust Approach for the Background Subtraction Based on Multi-Layered Self-Organizing Maps.

    Science.gov (United States)

    Gemignani, Giorgio; Rozza, Alessandro

    2016-11-01

    Motion detection in video streams is a challenging task for several computer vision applications. Indeed, segmentation of moving and static elements in the scene allows to increase the efficiency of several challenging tasks, such as human-computer interface, robot visions, and intelligent surveillance systems. In this paper, we approach motion detection through a multi-layered artificial neural network, which is able to build for each background pixel a multi-modal color distribution evolving over time through self-organization. According to the winner-take-all rule, each layer of the network models an independent state of the background scene, in response to external disturbing conditions, such as illumination variations, moving backgrounds, and jittering. As a result, our background subtraction method exhibits high generalization capabilities that in combination with a post-processing filtering schema allow to produce accurate motion segmentation. Moreover, we propose an approach to detect anomalous events (such as camera motion) that require background model re-initialization. We describe our method in full details and we compare it against the most recent background subtraction approaches. Experimental results for video sequences from the 2012 and 2014 CVPR Change Detection data sets demonstrate how our methodology outperforms many state-of-the-art methods in terms of detection rate.

  18. Influence of the large-small split effect on strategy choice in complex subtraction.

    Science.gov (United States)

    Xiang, Yan Hui; Wu, Hao; Shang, Rui Hong; Chao, Xiaomei; Ren, Ting Ting; Zheng, Li Ling; Mo, Lei

    2016-03-31

    Two main theories have been used to explain the arithmetic split effect: decision-making process theory and strategy choice theory. Using the inequality paradigm, previous studies have confirmed that individuals tend to adopt a plausibility-checking strategy and a whole-calculation strategy to solve large and small split problems in complex addition arithmetic, respectively. This supports strategy choice theory, but it is unknown whether this theory also explains performance in solving different split problems in complex subtraction arithmetic. This study used small, intermediate and large split sizes, with each split condition being further divided into problems requiring and not requiring borrowing. The reaction times (RTs) for large and intermediate splits were significantly shorter than those for small splits, while accuracy was significantly higher for large and middle splits than for small splits, reflecting no speed-accuracy trade-off. Further, RTs and accuracy differed significantly between the borrow and no-borrow conditions only for small splits. This study indicates that strategy choice theory is suitable to explain the split effect in complex subtraction arithmetic. That is, individuals tend to choose the plausibility-checking strategy or the whole-calculation strategy according to the split size. © 2016 International Union of Psychological Science.

  19. Doppler ultrasound spectral enhancement using the Gabor transform-based spectral subtraction.

    Science.gov (United States)

    Zhang, Yu; Zhang, Hong

    2005-10-01

    Most of the important clinical indices of blood flow are estimated from the spectrograms of Doppler ultrasound (US) signals. Any noise may degrade the readability of the spectrogram and the precision of the clinical indiCes, so the spectral enhancement plays an important role in Doppler US signal processing. A new Doppler US spectral enhancement method is proposed in this paper and implemented in three main steps: the Gabor transform is used to compute the Gabor coefficients of a Doppler US signal, the spectral subtraction is performed on the magnitude of the Gabor coefficients, and the Gabor expansion with the spectral subtracted Gabor coefficients is used to reconstruct the denoised Doppler US signal. The different analysis and synthesis windows are examined in the Gabor transform and expansion. The signal-to-noise ratio (SNR) improvement together with the overall enhancement of spectrograms are examined on the simulated Doppler US signals from a femoral artery. The results show the denoising method based on the orthogonal-like Gabor expansion achieves the best denoising performance. The experiments on some clinical Doppler US signals from umbilical arteries confirm the superior denoising performance of the new method.

  20. Perception-inspired background subtraction in complex scenes based on spatiotemporal features

    Science.gov (United States)

    Shi, Liu; Liu, Jiahang

    2016-10-01

    Background subtraction (BGS) is a fundamental preprocessing step in most video-based applications. Most BGS methods fail to handle dynamic unconstrained scenarios accurately. This is because of overreliance on statistical model. In this paper, we develop a novel non-parametric sample-based background subtraction method. First, the background sample set is initialized by a clean sample frame rather than the first frame. This can avoid introducing a ghost when the first frame contains foreground objects. Here, we utilize the Gaussian mixture model to validate whether a pixel at the location is clean or not and construct the initialization of background model. Second, for an actual scenario with diversified environmental conditions (e.g., illumination changes, dynamic background), we employ normalized color space and a scale invariant local ternary pattern operator to handle these variations. In the meantime, in order to achieve high detection accuracy in the unconstrained scenarios without requiring any scenario-specific parameter tuning, we employ the perception-inspired confidence interval to modify the threshold in the color space. Third, the hole filling approach is used to reduce noise which comes from false segmentation, fill the blank area in the foreground region and maintain the integrity of foreground object. Our experimental results indicate that the proposed approach is superior to several state-of-the-art methods in terms of F-score and kappa index.

  1. A subtraction pipeline for automatic detection of new appearing multiple sclerosis lesions in longitudinal studies

    Energy Technology Data Exchange (ETDEWEB)

    Ganiler, Onur; Oliver, Arnau; Diez, Yago; Freixenet, Jordi; Llado, Xavier [University of Girona, VICOROB Computer Vision and Robotics Group, Girona (Spain); Vilanova, Joan C. [Girona Magnetic Resonance Center, Girona (Spain); Beltran, Brigitte [Dr. Josep Trueta University Hospital, Institut d' Investigacio Biomedica de Girona, Girona (Spain); Ramio-Torrenta, Lluis [Dr. Josep Trueta University Hospital, Institut d' Investigacio Biomedica de Girona, Multiple Sclerosis and Neuroimmunology Unit, Girona (Spain); Rovira, Alex [Vall d' Hebron University Hospital, Magnetic Resonance Unit, Department of Radiology, Barcelona (Spain)

    2014-05-15

    Time-series analysis of magnetic resonance images (MRI) is of great value for multiple sclerosis (MS) diagnosis and follow-up. In this paper, we present an unsupervised subtraction approach which incorporates multisequence information to deal with the detection of new MS lesions in longitudinal studies. The proposed pipeline for detecting new lesions consists of the following steps: skull stripping, bias field correction, histogram matching, registration, white matter masking, image subtraction, automated thresholding, and postprocessing. We also combine the results of PD-w and T2-w images to reduce false positive detections. Experimental tests are performed in 20 MS patients with two temporal studies separated 12 (12M) or 48 (48M) months in time. The pipeline achieves very good performance obtaining an overall sensitivity of 0.83 and 0.77 with a false discovery rate (FDR) of 0.14 and 0.18 for the 12M and 48M datasets, respectively. The most difficult situation for the pipeline is the detection of very small lesions where the obtained sensitivity is lower and the FDR higher. Our fully automated approach is robust and accurate, allowing detection of new appearing MS lesions. We believe that the pipeline can be applied to large collections of images and also be easily adapted to monitor other brain pathologies. (orig.)

  2. Screening for metronidazole-resistance associated gene fragments of H pylori by suppression subtractive hybridization

    Institute of Scientific and Technical Information of China (English)

    Ai-Qing Li; Ning Dai; Jie Yan; Yong-Liang Zhu

    2007-01-01

    AIM:To screen for metronidazole (MTZ)-resistance associated gene fragments of H pylori by suppression subtractive hybridization (SSH).METHODS:Five MTZ-resistant (tester,T) and 1 MTZ-susceptible (driver,D) clinical H pylori isolates were selected. Genomic DMAs were prepared and submitted to Rsa I digestion. Then two different adaptors were ligated respectively to the 5'-end of two aliquots of the tester DNA fragments and SSH was made between the tester and driver DNAs. The specific inserts of tester strains were screened and MTZ-resistance related gene fragments were identified by dot blotting.RESULTS:Among the randomly selected 120 subtractive colonies,37 DNA fragments had a different number of DNA copies (≥2 times) in resistant and susceptible strains and 17 of them had a significantly different number of DNA copies (≥3 times). Among the sequences obtained from the 17 DNA fragments,new sequences were found in 10 DNA fragments and duplicated sequences in 7 DNA fragments,representing respectively the sequences of depeptide ABC transporter periplasmic dipeptide-binding protein (dppA),permease protein (dppB),ribosomal protein S4 (rps4),ribonuclease in (rnc),protease (pqqE),diaminopimelate epimerase (dapF),acetatekinase (ackA),H pylori plasmid pHPSl and H pylori gene 1334.CONCLUSION:Gene fragments specific to MTZ-resistant H pylori strains can be screened by SSH and may be associated with MTZ-resistant H pylori.

  3. Quantitative digital subtraction radiography for assessment of bone density changes following periodontal guided tissue regeneration.

    Science.gov (United States)

    Christgau, M; Wenzel, A; Hiller, K A; Schmalz, G

    1996-01-01

    The quantitative assessment of alveolar bone density changes in periodontal defects following guided tissue regeneration (GTR). Twelve patients with 30 intrabony lesions and 16 furcation defects took part. Standardized radiographic and clinical examinations were carried out immediately before and then 5 and 13 months after surgery. Intra-oral radiographs were evaluated by means of digital subtraction radiography (DSR). Within the subtraction images, a window ('experimental region') was defined covering the visible density changes in the defect area. Background noise was measured by using a similarly sized window ('control region') located in an area not affected by GTR. Bone density changes were quantitatively evaluated by calculation of the mean, standard deviation and maximum and minimum values of the grey-level histogram within these windows. DSR revealed significant bone density gain after GTR in intrabony and furcation defects. While a continuous increase was observed over the 13 month period in intrabony defects, changes in furcation defects occurred mostly in the 5-13 month period. Clinically, a distinct vertical and horizontal attachment gain was found. The correlation coefficients between changes in radiographic density and clinical parameters were low, indicating a difference in the information obtained by the two diagnostic methods. Quantitative DSR is a valuable, non-invasive, objective method to obtain information on density changes in intrabony and furcation defects treated by GTR. However, a full assessment of soft and hard tissue changes requires both clinical evaluation and DSR.

  4. Performance improvement of continuous-variable quantum key distribution with an entangled source in the middle via photon subtraction

    Science.gov (United States)

    Guo, Ying; Liao, Qin; Wang, Yijun; Huang, Duan; Huang, Peng; Zeng, Guihua

    2017-03-01

    A suitable photon-subtraction operation can be exploited to improve the maximal transmission of continuous-variable quantum key distribution (CVQKD) in point-to-point quantum communication. Unfortunately, the photon-subtraction operation faces solving the improvement transmission problem of practical quantum networks, where the entangled source is located in the third part, which may be controlled by a malicious eavesdropper, instead of in one of the trusted parts, controlled by Alice or Bob. In this paper, we show that a solution can come from using a non-Gaussian operation, in particular, the photon-subtraction operation, which provides a method to enhance the performance of entanglement-based (EB) CVQKD. Photon subtraction not only can lengthen the maximal transmission distance by increasing the signal-to-noise rate but also can be easily implemented with existing technologies. Security analysis shows that CVQKD with an entangled source in the middle (ESIM) from applying photon subtraction can well increase the secure transmission distance in both direct and reverse reconciliations of the EB-CVQKD scheme, even if the entangled source originates from an untrusted part. Moreover, it can defend against the inner-source attack, which is a specific attack by an untrusted entangled source in the framework of ESIM.

  5. Array-based techniques for fingerprinting medicinal herbs

    Directory of Open Access Journals (Sweden)

    Xue Charlie

    2011-05-01

    Full Text Available Abstract Poor quality control of medicinal herbs has led to instances of toxicity, poisoning and even deaths. The fundamental step in quality control of herbal medicine is accurate identification of herbs. Array-based techniques have recently been adapted to authenticate or identify herbal plants. This article reviews the current array-based techniques, eg oligonucleotides microarrays, gene-based probe microarrays, Suppression Subtractive Hybridization (SSH-based arrays, Diversity Array Technology (DArT and Subtracted Diversity Array (SDA. We further compare these techniques according to important parameters such as markers, polymorphism rates, restriction enzymes and sample type. The applicability of the array-based methods for fingerprinting depends on the availability of genomics and genetics of the species to be fingerprinted. For the species with few genome sequence information but high polymorphism rates, SDA techniques are particularly recommended because they require less labour and lower material cost.

  6. Polishability and wear resistance of splint material for oral appliances produced with conventional, subtractive, and additive manufacturing.

    Science.gov (United States)

    Huettig, Fabian; Kustermann, Achim; Kuscu, Ebru; Geis-Gerstorfer, Jürgen; Spintzyk, Sebastian

    2017-07-14

    Occlusal splints to treat bruxism are commonly made from polymethylmethacrylate (PMMA) in a manual workflow (powder-liquid technique). Today digitalization allows a machine-based manufacturing in subtractive (milling) and additive (printing) means using industrial-made PMMA or comparable resins. An in-vitro study should assess the surface finish and screen the wear resistance of conventional and industrial materials. Therefore, a total of 30 specimens made from conventionally PMMA (group C; powder-liquid, Palapress), polycarbonate ingots (group S; innoBlanc splint plus), and light-curing resin (group A; VarseoWax splint) were polished to examine the surface roughness (Ra) by profilometry and further analyzed by SEM. The specimens were loaded with a steatite ball moving 5000 times along 1cm with 5N of surface pressure under constant wetting (artificial saliva). The total height of profile (Pt) was calculated by further profilometry of the specimens. All specimen showed initially comparable Ra values ranging between 0.06 and 0.05µm (SD = 0.01) after polishing. SEM investigations revealed no visual cues for scratches or irregularities in any group. After abrasion test, the comparison of the wear depths, revealed mean Pt values of 111.4µm (SD = 18.5) in C, 85.7µm (SD = 21.5) in S, and 99.1µm (SD = 21.5) in A, whereas the mean of S was statistically different from C (p = 0.025). No signs of abrasion were found on the steatite balls. All materials showed comparable polished surfaces and a similar scale of wear. It remains questionable if the detected statistical differences are of clinical relevance, but indicates the need for tests of novel materials, especially in additive manufacturing. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Comparison and evaluation of marginal and internal gaps in cobalt-chromium alloy copings fabricated using subtractive and additive manufacturing.

    Science.gov (United States)

    Kim, Dong-Yeon; Kim, Ji-Hwan; Kim, Hae-Young; Kim, Woong-Chul

    2017-06-26

    To evaluate the marginal and internal gaps of cobalt-chromium (Co-Cr) alloy copings fabricated using subtractive and additive manufacturing. A study model of an abutment tooth 46 was prepared by a 2-step silicone impression with dental stone. Fifteen stereolithography files for Co-Cr alloy copings were compiled using a model scanner and dental CAD software. Using the lost wax (LW), wax block (WB), soft metal block (SMB), microstereolithography (μ-SLA), and selected laser melting (SLM) techniques, 15 Co-Cr alloy copings were fabricated per group. The marginal and internal gaps of these Co-Cr alloy copings were measured using a digital microscope (160×), and the data obtained were analyzed using the non-parametric Kruskal-Wallis H-test and post-hoc Mann-Whitney U-test with Bonferroni correction. The mean values of the marginal, axial wall, and occlusal gaps were 91.8, 83.4, and 163μm in the LW group; 94.2, 77.5, and 122μm in the WB group; 60.0, 79.4, and 90.8μm in the SMB group; 154, 72.4, and 258μm in the μ-SLA group; and 239, 73.6, and 384μm in the SLM group, respectively. The differences in the marginal and occlusal gaps between the 5 groups were statistically significant (P<.05). The marginal gaps of the LW, WB, and SMB groups were within the clinically acceptable limit, but further improvements in the μ-SLA and SLM approaches may be required prior to clinical implementation. Copyright © 2017 Japan Prosthodontic Society. Published by Elsevier Ltd. All rights reserved.

  8. Blood Pool Contrast-enhanced Magnetic Resonance Angiography with Correlation to Digital Subtraction Angiography: A Pictorial Review

    Directory of Open Access Journals (Sweden)

    Martha-Grace Knuttinen

    2014-01-01

    Full Text Available Magnetic resonance angiography (MRA provides noninvasive visualization of the vascular supply of soft tissue masses and vascular pathology, without harmful radiation. This is important for planning an endovascular intervention, and helps to evaluate the efficiency and effectiveness of the treatment. MRA with conventional extracellular contrast agents relies on accurate contrast bolus timing, limiting the imaging window to first-pass arterial phase. The recently introduced blood pool contrast agent (BPCA, gadofosveset trisodium, reversibly binds to human serum albumin, resulting in increased T1 relaxivity and prolonged intravascular retention time, permitting both first-pass and steady-state phase high-resolution imaging. In our practice, high-quality MRA serves as a detailed "roadmap" for the needed endovascular intervention. Cases of aortoiliac occlusive disease, inferior vena cava thrombus, pelvic congestion syndrome, and lower extremity arteriovenous malformation are discussed in this article. MRA was acquired at 1.5 T with an 8-channel phased array coil after intravenous administration of gadofosveset (0.03 mmol/kg body weight, at the first-pass phase. In the steady-state, serial T1-weighted 3D spoiled gradient echo images were obtained with high resolution. All patients underwent digital subtraction angiography (DSA and endovascular treatment. MRA and DSA findings of vascular anatomy and pathology are discussed and correlated. BPCA-enhanced MRA provides high-quality first-pass and steady-state vascular imaging. This could increase the diagnostic accuracy and create a detailed map for pre-intervention planning. Understanding the pharmacokinetics of BPCA and being familiar with the indications and technique of MRA are important for diagnosis and endovascular intervention.

  9. Intra-Arterial MR Perfusion Imaging of Meningiomas: Comparison to Digital Subtraction Angiography and Intravenous MR Perfusion Imaging

    Science.gov (United States)

    Martin, Alastair J.; Alexander, Matthew D.; McCoy, David B.; Cooke, Daniel L.; Lillaney, Prasheel; Moftakhar, Parham; Amans, Matthew R.; Settecase, Fabio; Nicholson, Andrew; Dowd, Christopher F.; Halbach, Van V.; Higashida, Randall T.; McDermott, Michael W.; Saloner, David; Hetts, Steven W.

    2016-01-01

    Background and Purpose To evaluate the ability of IA MR perfusion to characterize meningioma blood supply. Methods Studies were performed in a suite comprised of an x-ray angiography unit and 1.5T MR scanner that permitted intraprocedural patient movement between the imaging modalities. Patients underwent intra-arterial (IA) and intravenous (IV) T2* dynamic susceptibility MR perfusion immediately prior to meningioma embolization. Regional tumor arterial supply was characterized by digital subtraction angiography and classified as external carotid artery (ECA) dural, internal carotid artery (ICA) dural, or pial. MR perfusion data regions of interest (ROIs) were analyzed in regions with different vascular supply to extract peak height, full-width at half-maximum (FWHM), relative cerebral blood flow (rCBF), relative cerebral blood volume (rCBV), and mean transit time (MTT). Linear mixed modeling was used to identify perfusion curve parameter differences for each ROI for IA and IV MR imaging techniques. IA vs. IV perfusion parameters were also directly compared for each ROI using linear mixed modeling. Results 18 ROIs were analyzed in 12 patients. Arterial supply was identified as ECA dural (n = 11), ICA dural (n = 4), or pial (n = 3). FWHM, rCBV, and rCBF showed statistically significant differences between ROIs for IA MR perfusion. Peak Height and FWHM showed statistically significant differences between ROIs for IV MR perfusion. RCBV and MTT were significantly lower for IA perfusion in the Dural ECA compared to IV perfusion. Relative CBF in IA MR was found to be significantly higher in the Dural ICA region and MTT significantly lower compared to IV perfusion. PMID:27802268

  10. Construction of a hepatic stellate cells subtracted cDNA library of differentially expressed genes in normal mice and mice with Schistosomiasis japonica*

    OpenAIRE

    2005-01-01

    To construct a hepatic stellate cells (HSCs) subtracted cDNA library to find differentially expressed genes in normal mice and mice infected with Schistosoma japonicum (S. japonicum). Suppression subtractive hybridization (SSH) was used. The cDNA fragments of normal mouse were compared to those of schistosoma-infected mice to find differentially expressed genes. Then differentially expressed cDNA fragments were directly inserted into T/A cloning vector to set up the subtractive library. Ampli...

  11. Self-adaptive prediction of cloud resource demands using ensemble model and subtractive-fuzzy clustering based fuzzy neural network.

    Science.gov (United States)

    Chen, Zhijia; Zhu, Yuanchang; Di, Yanqiang; Feng, Shaochong

    2015-01-01

    In IaaS (infrastructure as a service) cloud environment, users are provisioned with virtual machines (VMs). To allocate resources for users dynamically and effectively, accurate resource demands predicting is essential. For this purpose, this paper proposes a self-adaptive prediction method using ensemble model and subtractive-fuzzy clustering based fuzzy neural network (ESFCFNN). We analyze the characters of user preferences and demands. Then the architecture of the prediction model is constructed. We adopt some base predictors to compose the ensemble model. Then the structure and learning algorithm of fuzzy neural network is researched. To obtain the number of fuzzy rules and the initial value of the premise and consequent parameters, this paper proposes the fuzzy c-means combined with subtractive clustering algorithm, that is, the subtractive-fuzzy clustering. Finally, we adopt different criteria to evaluate the proposed method. The experiment results show that the method is accurate and effective in predicting the resource demands.

  12. Improvement of the dynamic range using background subtraction in single shot wide-field optical coherence tomography

    Science.gov (United States)

    Anna, Tulsi; Singh Mehta, Dalip; Sato, Manabu

    2015-12-01

    We investigated on the signal in single shot wide-field optical coherence tomographic (SS-WF-OCT) system to improve the dynamic range (DR). The SS-WF-OCT system is based on two-dimensional (2D) polarization Michelson interferometer and superluminescent diode (center wavelength of 842.5 nm) as light source. Two π-phase-shifted interferograms were acquired simultaneously using a single CCD camera and after subtraction, the en-face OCT image (area (x) 4.0 mm × (y) 4.3 mm) is obtained using 2D Hilbert transform. The OCT signal including incoherent background noises was analyzed. To improve the DR, background noise subtraction has been introduced and its measurement process is presented. This method is valuable during the background noise is stable. Using the scattering samples, such as, grind metal and polymer sponge with background subtraction algorithm, a significant reduction in background noise and improvement in the DR was demonstrated .

  13. Confirmation of T1-Bright Vein of Galen Aneurysm Spontaneous Thrombosis by Subtraction Magnetic Resonance Venography: A Case Report

    Energy Technology Data Exchange (ETDEWEB)

    Irfan, M.; Lohman, B.; McKinney, A.M. (Dept. of Radiology/Neuroradiology, Univ. of Minnesota, Minneapolis, Minnesota (United States))

    2009-08-15

    Spontaneous thrombosis of a vein of Galen aneurysmal malformation (VOGM) is rare. We describe a 2-month-old patient with a patent VOGM and hydrocephalus, also confirmed patent at 6 months, but with subsequent lack of filling on pre-embolization catheter digital subtraction angiography (DSA) at 9 months' age. Due to the presence of T1- and T2-bright signal, noncontrast T1-weighted images (T1WI), T2-weighted images (T2WI), two-dimensional (2D) time-of-flight (TOF) magnetic resonance venography (MRV), and postcontrast T1WI were ambiguous for patency. However, subtracting the pre- from the postcontrast MRV images confirmed closure compared to subtracted images at 6 months' age. The factors contributing to thrombosis were likely a combination of a disproportionately small straight sinus, ventriculostomy, and contrast medium from DSA.

  14. Nonclassicality and Entanglement of Photon-Subtracted Two-Mode Squeezed Coherent States Studied via Entangled-States Representation

    Science.gov (United States)

    Wang, Zhen; Li, Heng-Mei; Yuan, Hong-Chun

    2016-10-01

    We theoretically introduce a kind of non-Gaussian entangled states, i.e., photon-subtracted two-mode squeezed coherent states (PSTMSCS), by successively subtracting photons from each mode of the two-mode squeezed coherent states. The normalization factor which is related to bivariate Hermite polynomials is obtained by virtue of the two-mode squeezing operator in entangled-states representation. The sub-Poissonian photon statistics, antibunching effects, and partial negative Wigner function, respectively, are observed numerically, which fully reflect the nonclassicality of the resultant states. Finally, employing the SV criteria and the EPR correlation, respectively, the entangled property of PSTMSCS is analyzed. It is shown that the photon subtraction operation can effectively enhance the inseparability between the two modes.

  15. Self-Adaptive Prediction of Cloud Resource Demands Using Ensemble Model and Subtractive-Fuzzy Clustering Based Fuzzy Neural Network

    Science.gov (United States)

    Chen, Zhijia; Zhu, Yuanchang; Di, Yanqiang; Feng, Shaochong

    2015-01-01

    In IaaS (infrastructure as a service) cloud environment, users are provisioned with virtual machines (VMs). To allocate resources for users dynamically and effectively, accurate resource demands predicting is essential. For this purpose, this paper proposes a self-adaptive prediction method using ensemble model and subtractive-fuzzy clustering based fuzzy neural network (ESFCFNN). We analyze the characters of user preferences and demands. Then the architecture of the prediction model is constructed. We adopt some base predictors to compose the ensemble model. Then the structure and learning algorithm of fuzzy neural network is researched. To obtain the number of fuzzy rules and the initial value of the premise and consequent parameters, this paper proposes the fuzzy c-means combined with subtractive clustering algorithm, that is, the subtractive-fuzzy clustering. Finally, we adopt different criteria to evaluate the proposed method. The experiment results show that the method is accurate and effective in predicting the resource demands. PMID:25691896

  16. Using the hydrophobic subtraction model to choose orthogonal columns for online comprehensive two-dimensional liquid chromatography

    DEFF Research Database (Denmark)

    Græsbøll, Rune; Nielsen, Nikoline Juul; Christensen, Jan H.

    2014-01-01

    A method for choosing orthogonal columns for a specific sample set in on-line comprehensive two-dimensional liquid chromatography (LC×LC) was developed on the basis of the hydrophobic subtraction model. The method takes into account the properties of the sample analytes by estimating new F...... by Gilroy et al. [1], (3) F-weights determined from the retention of sample analytes but using principal component analysis (PCA) for the estimation, and (4) the Gilroy F-weights modified by excluding the C-term in the hydrophobic subtraction model, as suggested by Dolan and Snyder [2]. The retention of 13...... neutral and 4 acidic oxygenated polycyclic aromatic compounds (PACs) and 3 nitrogen-containing PAC bases was measured isocratically on 12 columns. The isocratic runs were used to determine the hydrophobic subtraction model analyte parameters, and these were used to estimate new F-weights and predict...

  17. Accuracy of digital subtraction radiography in combination with a contrast media in assessment of proximal caries depth.

    Science.gov (United States)

    Valizadeh, Solmaz; Ehsani, Sara; Esmaeili, Farzad; Tavakoli, Mohammad Amin

    2008-01-01

    Radiography is used to diagnose the demineralization process and carious lesions; however, conventional radiography and direct digital images do not show these lesions when the amount of demineralization is less than 40%. Digital subtraction radiography has recently been used to improve the diagnostic quality of these le-sions. The purpose of this study was to compare the caries depth estimated by digital subtraction radiog-raphy in combination with barium sulfate in diag-nosing proximal dental caries with histopathologic evaluation. In this study 30 molars and premolars (24 demineralized lesions with cavity, 8 without cavity) were studied. Direct digital images were taken (kVp: 68, mA: 8; t: 0.12 for premolars and t: 0.16 for molars) whereas the position of X-ray tube and CCD receptor and teeth was fixed. To prepare the second images 135 gr/L barium sulfate was used. The images obtained with the same exposure and geometry and then subtracted. The depth of the lesions in direct digital and subtracted images were assessed and compared with the depth measured in histopathologic assessments. The mean depths (± SD) of the lesions were 1.80 ± 0.77 mm in direct digital radiography, 2.32 ± 0.76 mm in subtracted images after barium sulfate treatment, and 2.51 ± 0.43 mm in histopathologic sections. The statistical difference between direct digital radiography and the other methods was significant (P digital subtraction radiography images have the potential to measure the depth of proximal caries with no significant difference with histopathologic evaluation.

  18. Value of subtraction MRI in assessing treatment response following image-guided loco-regional therapies for hepatocellular carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Winters, S.D. [Department of Radiology and Diagnostic Imaging, Royal Alexandra Hospital, Edmonton (Canada); Department of Radiology and Diagnostic Imaging, University of Alberta Hospital, Edmonton (Canada); 1 Canadian Field Hospital, Department of National Defence, Government of Canada (Canada); Jackson, S. [Department of Radiology and Diagnostic Imaging, University of Alberta Hospital, Edmonton (Canada); Armstrong, G.A. [Department of Radiology and Diagnostic Imaging, Royal Alexandra Hospital, Edmonton (Canada); Department of Radiology and Diagnostic Imaging, University of Alberta Hospital, Edmonton (Canada); Birchall, I.W. [Department of Radiology and Diagnostic Imaging, University of Alberta Hospital, Edmonton (Canada); Lee, K.H.Y. [Department of Radiology and Diagnostic Imaging, Royal Alexandra Hospital, Edmonton (Canada); Low, G., E-mail: timgy@yahoo.com [Department of Radiology and Diagnostic Imaging, University of Alberta Hospital, Edmonton (Canada)

    2012-07-15

    Aim: To compare contrast-enhanced subtraction magnetic resonance imaging (MRI) with contrast-enhanced standard MRI in assessing treatment response following loco-regional therapies for hepatocellular carcinoma (HCC). Method and materials: Institutional review board approval was obtained and informed consent was waived for this retrospective study. All patients were analysed from our institution's liver tumour database that had loco-regional HCC therapy and the following: (1) a contrast-enhanced MRI {<=}6 weeks post-treatment, (2) an unenhanced T1-weighted high-signal treatment zone (TZ) {>=}1 cm, (3) follow-up contrast-enhanced MRI performed {>=}6 months post-treatment. Randomized standard and subtraction TZ datasets were independently assessed by three blinded radiology readers for either complete treatment necrosis or residual disease. The standard of reference (SOR) comprised a consensus read by two radiologists with knowledge of the follow-up MRI and all available clinical data. Statistical analyses were performed using receiver operating characteristics (ROC), t-test, and kappa statistic. Results: Twenty-six patients (19 male and seven female patients; mean age 60 years, standard deviation 10.9 years, range 46-88 years) had a total of 45 corresponding HCCs and TZs. For ROC, the area under the curve (AUC) was 0.93 (subtraction protocol) versus 0.90 (standard protocol; p = 0.49). For the t-test, the mean reader confidence level was 4.4, 3.6, and 4.4 (subtraction protocol) versus 3, 3, and 3.7 (standard protocol; p {<=} 0.011). The kappa statistic for reader-to-SOR agreement was 0.83, 0.63, and 0.71 (subtraction protocol) versus 0.51, 0.36, and 0.64 (standard protocol). Conclusion: Subtraction MRI significantly improves the reader confidence level in the assessment of treatment response following loco-regional therapies for HCC.

  19. Screening and cloning of differentially expressed genes in placentas from patients of pregnancy-induced hypertension by suppression subtractive hybridization

    Institute of Scientific and Technical Information of China (English)

    尹国武; 姜锋; 李东红; 姚元庆

    2003-01-01

    Suppresssion subtractive hybridization (SSH) was preformed to compare gene expression profiles of PIH patients and normal pregnancy placentas. The subtractive cDNA library of PIH placenta was set up and screedned. Differential cDNAs were cloned, and sequenced by T 7 primer methodology. One hundred and three differential cDNAs were isolated by SSH. Sequencing and BLAST analysis showed 90 inserts shared more than 95% homolog with sequences in the GenBank/EMBL database. We identified 36 putative genes including pregnancy-specific glycoprotein gene (BC005924), serine protease inhibitor gene(BC012868), VEGFR-1 gene(AF063657, etc.

  20. Sigma pole position and errors of a once and twice subtracted dispersive analysis of pi-pi scattering data

    Energy Technology Data Exchange (ETDEWEB)

    Kaminski, R. [Department of Theoretical Physics, H. Niewodniczanski Institute of Nuclear Physics, Polish Academy of Sciences, 31-342 Krakow (Poland); Garcia-Martin, R. [Departamento de Fisica Teorica, II (Metodos Matematicos), Facultad de Ciencias Fisicas, Universidad Complutense de Madrid, E-28040, Madrid (Spain); Grynkiewicz, P. [ul. Paulinska, 6/18 Krakow 31-065 (Poland); Pelaez, J.R. [Departamento de Fisica Teorica, II (Metodos Matematicos), Facultad de Ciencias Fisicas, Universidad Complutense de Madrid, E-28040, Madrid (Spain)

    2009-01-15

    We show how the new precise data on kaon decays together with forward dispersion relations, sum rules and once- and twice-subtracted Roy's equations allow for a precise determination of the sigma meson pole position. We present a comparison and a study of the different sources of uncertainties when using either once- or twice-subtracted Roy's equations to analyze the data. Finally we present a preliminary determination of the {sigma} pole from the constrained dispersive data analysis.