Sample records for image derived input

  1. Quantitative Amyloid Imaging Using Image-Derived Arterial Input Function

    PubMed Central

    Su, Yi; Blazey, Tyler M.; Snyder, Abraham Z.; Raichle, Marcus E.; Hornbeck, Russ C.; Aldea, Patricia; Morris, John C.; Benzinger, Tammie L. S.

    2015-01-01

    Amyloid PET imaging is an indispensable tool widely used in the investigation, diagnosis and monitoring of Alzheimer’s disease (AD). Currently, a reference region based approach is used as the mainstream quantification technique for amyloid imaging. This approach assumes the reference region is amyloid free and has the same tracer influx and washout kinetics as the regions of interest. However, this assumption may not always be valid. The goal of this work is to evaluate an amyloid imaging quantification technique that uses arterial region of interest as the reference to avoid potential bias caused by specific binding in the reference region. 21 participants, age 58 and up, underwent Pittsburgh compound B (PiB) PET imaging and MR imaging including a time-of-flight (TOF) MR angiography (MRA) scan and a structural scan. FreeSurfer based regional analysis was performed to quantify PiB PET data. Arterial input function was estimated based on coregistered TOF MRA using a modeling based technique. Regional distribution volume (VT) was calculated using Logan graphical analysis with estimated arterial input function. Kinetic modeling was also performed using the estimated arterial input function as a way to evaluate PiB binding (DVRkinetic) without a reference region. As a comparison, Logan graphical analysis was also performed with cerebellar cortex as reference to obtain DVRREF. Excellent agreement was observed between the two distribution volume ratio measurements (r>0.89, ICC>0.80). The estimated cerebellum VT was in line with literature reported values and the variability of cerebellum VT in the control group was comparable to reported variability using arterial sampling data. This study suggests that image-based arterial input function is a viable approach to quantify amyloid imaging data, without the need of arterial sampling or a reference region. This technique can be a valuable tool for amyloid imaging, particularly in population where reference normalization may not be accurate. PMID:25849581

  2. Characterization of the image-derived carotid artery input function using independent component analysis for the

    E-print Network

    Renaut, Rosemary

    -derived input function by ICA for FDG-PET K Chen1,3,8 , X Chen2 , R Renaut3,5,8 , G E Alexander4,8 , D Bandy1) positron emission tomography (PET) images using an image- derived input function obtained from a manually1 Characterization of the image-derived carotid artery input function using independent component

  3. Improved Imaged-derived Input Function for Study of Human Brain FDG-PET

    E-print Network

    Renaut, Rosemary

    Improved Imaged-derived Input Function for Study of Human Brain FDG-PET Hongbin Guo, Rosemary Improved Imaged-derived Input Function for Study of Human Brain FDG-PET I. INTRODUCTION Positron emission-invasive image-derived input function is validated for human [18 F]-fluoro deoxyglucose (FDG) positron emission

  4. Image-Derived Input Function for Human Brain Using High Resolution PET Imaging with [11

    E-print Network

    Shen, Jun

    ](R)-rolipram and [11 C]PBR28 Paolo Zanotti-Fregonara1 *, Jeih-San Liow1 , Masahiro Fujita1 , Elodie Dusch2 , Sami S of the methods required arterial blood samples to scale the image-input, and four were blood-free methods-S, Fujita M, Dusch E, Zoghbi SS, et al. (2011) Image-Derived Input Function for Human Brain Using High

  5. Characterization of the image-derived carotid artery input function using independent component analysis for the quantitation of [18F] fluorodeoxyglucose positron emission tomography images

    NASA Astrophysics Data System (ADS)

    Chen, K.; Chen, X.; Renaut, R.; Alexander, G. E.; Bandy, D.; Guo, H.; Reiman, E. M.

    2007-12-01

    We previously developed a noninvasive technique for the quantification of fluorodeoxyglucose (FDG) positron emission tomography (PET) images using an image-derived input function obtained from a manually drawn carotid artery region. Here, we investigate the use of independent component analysis (ICA) for more objective identification of the carotid artery and surrounding tissue regions. Using FDG PET data from 22 subjects, ICA was applied to an easily defined cubical region including the carotid artery and neighboring tissue. Carotid artery and tissue time activity curves and three venous samples were used to generate spillover and partial volume-corrected input functions and to calculate the parametric images of the cerebral metabolic rate for glucose (CMRgl). Different from a blood-sampling-free ICA approach, the results from our ICA approach are numerically well matched to those based on the arterial blood sampled input function. In fact, the ICA-derived input functions and CMRgl measurements were not only highly correlated (correlation coefficients >0.99) to, but also highly comparable (regression slopes between 0.92 and 1.09), with those generated using arterial blood sampling. Moreover, the reliability of the ICA-derived input function remained high despite variations in the location and size of the cubical region. The ICA procedure makes it possible to quantify FDG PET images in an objective and reproducible manner. Image-derived input function by ICA for FDG-PET.

  6. Noninvasive image derived heart input function for CMRglc measurements in small animal slow infusion FDG PET studies.

    PubMed

    Xiong, Guoming; Paul, Cumming; Todica, Andrei; Hacker, Marcus; Bartenstein, Peter; Böning, Guido

    2012-12-01

    Absolute quantitation of the cerebral metabolic rate for glucose (CMRglc) can be obtained in positron emission tomography (PET) studies when serial measurements of the arterial [(18)F]-fluoro-deoxyglucose (FDG) input are available. Since this is not always practical in PET studies of rodents, there has been considerable interest in defining an image-derived input function (IDIF) by placing a volume of interest (VOI) within the left ventricle of the heart. However, spill-in arising from trapping of FDG in the myocardium often leads to progressive contamination of the IDIF, which propagates to underestimation of the magnitude of CMRglc. We therefore developed a novel, non-invasive method for correcting the IDIF without scaling to a blood sample. To this end, we first obtained serial arterial samples and dynamic FDG-PET data of the head and heart in a group of eight anaesthetized rats. We fitted a bi-exponential function to the serial measurements of the IDIF, and then used the linear graphical Gjedde-Patlak method to describe the accumulation in myocardium. We next estimated the magnitude of myocardial spill-in reaching the left ventricle VOI by assuming a Gaussian point-spread function, and corrected the measured IDIF for this estimated spill-in. Finally, we calculated parametric maps of CMRglc using the corrected IDIF, and for the sake of comparison, relative to serial blood sampling from the femoral artery. The uncorrected IDIF resulted in 20% underestimation of the magnitude of CMRglc relative to the gold standard arterial input method. However, there was no bias with the corrected IDIF, which was robust to the variable extent of myocardial tracer uptake, such that there was a very high correlation between individual CMRglc measurements using the corrected IDIF with gold-standard arterial input results. Based on simulation, we furthermore find that electrocardiogram-gating, i.e. ECG-gating is not necessary for IDIF quantitation using our approach. PMID:23160517

  7. Noninvasive image derived heart input function for CMRglc measurements in small animal slow infusion FDG PET studies

    NASA Astrophysics Data System (ADS)

    Xiong, Guoming; Cumming, Paul; Todica, Andrei; Hacker, Marcus; Bartenstein, Peter; Böning, Guido

    2012-12-01

    Absolute quantitation of the cerebral metabolic rate for glucose (CMRglc) can be obtained in positron emission tomography (PET) studies when serial measurements of the arterial [18F]-fluoro-deoxyglucose (FDG) input are available. Since this is not always practical in PET studies of rodents, there has been considerable interest in defining an image-derived input function (IDIF) by placing a volume of interest (VOI) within the left ventricle of the heart. However, spill-in arising from trapping of FDG in the myocardium often leads to progressive contamination of the IDIF, which propagates to underestimation of the magnitude of CMRglc. We therefore developed a novel, non-invasive method for correcting the IDIF without scaling to a blood sample. To this end, we first obtained serial arterial samples and dynamic FDG-PET data of the head and heart in a group of eight anaesthetized rats. We fitted a bi-exponential function to the serial measurements of the IDIF, and then used the linear graphical Gjedde-Patlak method to describe the accumulation in myocardium. We next estimated the magnitude of myocardial spill-in reaching the left ventricle VOI by assuming a Gaussian point-spread function, and corrected the measured IDIF for this estimated spill-in. Finally, we calculated parametric maps of CMRglc using the corrected IDIF, and for the sake of comparison, relative to serial blood sampling from the femoral artery. The uncorrected IDIF resulted in 20% underestimation of the magnitude of CMRglc relative to the gold standard arterial input method. However, there was no bias with the corrected IDIF, which was robust to the variable extent of myocardial tracer uptake, such that there was a very high correlation between individual CMRglc measurements using the corrected IDIF with gold-standard arterial input results. Based on simulation, we furthermore find that electrocardiogram-gating, i.e. ECG-gating is not necessary for IDIF quantitation using our approach.

  8. Image-derived input function derived from a supervised clustering algorithm: methodology and validation in a clinical protocol using [11C](R)-rolipram.

    PubMed

    Lyoo, Chul Hyoung; Zanotti-Fregonara, Paolo; Zoghbi, Sami S; Liow, Jeih-San; Xu, Rong; Pike, Victor W; Zarate, Carlos A; Fujita, Masahiro; Innis, Robert B

    2014-01-01

    Image-derived input function (IDIF) obtained by manually drawing carotid arteries (manual-IDIF) can be reliably used in [(11)C](R)-rolipram positron emission tomography (PET) scans. However, manual-IDIF is time consuming and subject to inter- and intra-operator variability. To overcome this limitation, we developed a fully automated technique for deriving IDIF with a supervised clustering algorithm (SVCA). To validate this technique, 25 healthy controls and 26 patients with moderate to severe major depressive disorder (MDD) underwent T1-weighted brain magnetic resonance imaging (MRI) and a 90-minute [(11)C](R)-rolipram PET scan. For each subject, metabolite-corrected input function was measured from the radial artery. SVCA templates were obtained from 10 additional healthy subjects who underwent the same MRI and PET procedures. Cluster-IDIF was obtained as follows: 1) template mask images were created for carotid and surrounding tissue; 2) parametric image of weights for blood were created using SVCA; 3) mask images to the individual PET image were inversely normalized; 4) carotid and surrounding tissue time activity curves (TACs) were obtained from weighted and unweighted averages of each voxel activity in each mask, respectively; 5) partial volume effects and radiometabolites were corrected using individual arterial data at four points. Logan-distribution volume (V T/f P) values obtained by cluster-IDIF were similar to reference results obtained using arterial data, as well as those obtained using manual-IDIF; 39 of 51 subjects had a V T/f P error of <5%, and only one had error >10%. With automatic voxel selection, cluster-IDIF curves were less noisy than manual-IDIF and free of operator-related variability. Cluster-IDIF showed widespread decrease of about 20% [(11)C](R)-rolipram binding in the MDD group. Taken together, the results suggest that cluster-IDIF is a good alternative to full arterial input function for estimating Logan-V T/f P in [(11)C](R)-rolipram PET clinical scans. This technique enables fully automated extraction of IDIF and can be applied to other radiotracers with similar kinetics. PMID:24586526

  9. Population-based input function and image-derived input function for [11C](R)-rolipram PET imaging: methodology, validation and application to the study of major depressive disorder

    PubMed Central

    Zanotti-Fregonara, Paolo; Hines, Christina S.; Zoghbi, Sami S.; Liow, Jeih-San; Zhang, Yi; Pike, Victor W.; Drevets, Wayne C.; Mallinger, Alan G.; Zarate, Carlos A.; Fujita, Masahiro; Innis, Robert B.

    2012-01-01

    Quantitative PET studies of neuroreceptor tracers typically require that arterial input function be measured. The aim of this study was to explore the use of a population-based input function (PBIF) and an image-derived input function (IDIF) for [11C](R)-rolipram kinetic analysis, with the goal of reducing—and possibly eliminating—the number of arterial blood samples needed to measure parent radioligand concentrations. Methods A PBIF was first generated using [11C](R)-rolipram parent time-activity curves from 12 healthy volunteers (Group 1). Both invasive (blood samples) and non-invasive (body weight, body surface area, and lean body mass) scaling methods for PBIF were tested. The scaling method that gave the best estimate of the Logan-VT values was then used to determine the test-retest variability of PBIF in Group 1 and then prospectively applied to another population of 25 healthy subjects (Group 2), as well as to a population of 28 patients with major depressive disorder (Group 3). Results were also compared to those obtained with an image-derived input function (IDIF) from the internal carotid artery. In some subjects, we measured arteriovenous differences in [11C](R)-rolipram concentration to see whether venous samples could be used instead of arterial samples. Finally, we assessed the ability of IDIF and PBIF to discriminate depressed patients (MDD) and healthy subjects. Results Arterial blood-scaled PBIF gave better results than any non-invasive scaling technique. Excellent results were obtained when the blood-scaled PBIF was prospectively applied to the subjects in Group 2 (VT ratio 1.02 ± 0.05; mean ± SD) and Group 3 (VT ratio 1.03 ± 0.04). Equally accurate results were obtained for two subpopulations of subjects drawn from Groups 2 and 3 who had very differently shaped (i.e. “flatter” or “steeper”) input functions compared to PBIF (VT ratio 1.07 ± 0.04 and 0.99 ± 0.04, respectively). Results obtained via PBIF were equivalent to those obtained via IDIF (VT ratio 0.99 ± 0.05 and 1.00 ± 0.04 for healthy subjects and MDD patients, respectively). Retest variability of PBIF was equivalent to that obtained with full input function and IDIF (14.5%, 15.2%, and 14.1%, respectively). Due to [11C](R)-rolipram arteriovenous differences, venous samples could not be substituted for arterial samples. With both IDIF and PBIF, depressed patients had a 20% reduction in [11C](R)-rolipram binding as compared to control (two-way ANOVA: p=0.008 and 0.005, respectively). These results were almost equivalent to those obtained using 23 arterial samples. Conclusion Although some arterial samples are still necessary, both PBIF and IDIF are accurate and precise alternatives to full arterial input function for [11C](R)-rolipram PET studies. Both techniques give accurate results with low variability, even for clinically different groups of subjects and those with very differently shaped input functions. PMID:22906792

  10. Cerebral blood flow with [15O]water PET studies using an image-derived input function and MR-defined carotid centerlines

    NASA Astrophysics Data System (ADS)

    Fung, Edward K.; Carson, Richard E.

    2013-03-01

    Full quantitative analysis of brain PET data requires knowledge of the arterial input function into the brain. Such data are normally acquired by arterial sampling with corrections for delay and dispersion to account for the distant sampling site. Several attempts have been made to extract an image-derived input function (IDIF) directly from the internal carotid arteries that supply the brain and are often visible in brain PET images. We have devised a method of delineating the internal carotids in co-registered magnetic resonance (MR) images using the level-set method and applying the segmentations to PET images using a novel centerline approach. Centerlines of the segmented carotids were modeled as cubic splines and re-registered in PET images summed over the early portion of the scan. Using information from the anatomical center of the vessel should minimize partial volume and spillover effects. Centerline time-activity curves were taken as the mean of the values for points along the centerline interpolated from neighboring voxels. A scale factor correction was derived from calculation of cerebral blood flow (CBF) using gold standard arterial blood measurements. We have applied the method to human subject data from multiple injections of [15O]water on the HRRT. The method was assessed by calculating the area under the curve (AUC) of the IDIF and the CBF, and comparing these to values computed using the gold standard arterial input curve. The average ratio of IDIF to arterial AUC (apparent recovery coefficient: aRC) across 9 subjects with multiple (n = 69) injections was 0.49 ± 0.09 at 0-30 s post tracer arrival, 0.45 ± 0.09 at 30-60 s, and 0.46 ± 0.09 at 60-90 s. Gray and white matter CBF values were 61.4 ± 11.0 and 15.6 ± 3.0 mL/min/100 g tissue using sampled blood data. Using IDIF centerlines scaled by the average aRC over each subjects’ injections, gray and white matter CBF values were 61.3 ± 13.5 and 15.5 ± 3.4 mL/min/100 g tissue. Using global average aRC values, the means were unchanged, and intersubject variability was noticeably reduced. This MR-based centerline method with local re-registration to [15O]water PET yields a consistent IDIF over multiple injections in the same subject, thus permitting the absolute quantification of CBF without arterial input function measurements.

  11. Cerebral blood flow with [15O]water PET studies using image-derived input function and MR-defined carotid centerlines

    PubMed Central

    Fung, Edward K; Carson, Richard E

    2013-01-01

    Full quantitative analysis of brain PET data requires knowledge of the arterial input function into the brain. Such data are normally acquired by arterial sampling with corrections for delay and dispersion to account for the distant sampling site. Several attempts have been made to extract an image-derived input function (IDIF) directly from the internal carotid arteries that supply the brain and are often visible in brain PET images. We have devised a method of delineating the internal carotids in co-registered MR images using the level-set method and applying the segmentations to PET images using a novel centerline approach. Centerlines of the segmented carotids were modeled as cubic splines and re-registered in PET images summed over the early portion of the scan. Using information from the anatomical center of the vessel should minimize partial volume and spillover effects. Centerline time-activity curves were taken as the mean of the values for points along the centerline interpolated from neighboring voxels. A scale factor correction was derived from calculation of cerebral blood flow (CBF) using gold standard arterial blood measurements. We have applied the method to human subject data from multiple injections of [15O]water on the HRRT. The method was assessed by calculating the area under the curve (AUC) of the IDIF and the CBF, and comparing these to values computed using the gold standard arterial input curve. The average ratio of IDIF to arterial AUC (apparent recovery coefficient: aRC) across 9 subjects with multiple (n = 69) injections was 0.49 ± 0.09 at 0–30 s post tracer arrival, 0.45 ± 0.09 at 30–60 s, and 0.46 ± 0.09 at 60–90 s. Grey and white matter CBF values were 61.4 ± 11.0 and 15.6 ± 3.0 mL/min/100g tissue using sampled blood data. Using IDIF centerlines scaled by the average aRC over each subjects’ injections, gray and white matter CBF values were 61.3 ± 13.5 and 15.5 ± 3.4 mL/min/100g tissue. Using global average aRC values, the means were unchanged, and intersubject variability was noticeably reduced. This MR-based centerline method with local re-registration to [15O]water PET yields a consistent IDIF over multiple injections in the same subject, thus permitting the absolute quantification of CBF without arterial input function measurements. PMID:23442733

  12. Calibrated image-derived input functions for the determination of the metabolic uptake rate of glucose with [18F]-FDG PET

    PubMed Central

    Reichkendler, Michala H.; Larsen, Rasmus; Auerbach, Pernille; Højgaard, Liselotte; Nielsen, Henning B.; Ploug, Thorkil; Stallknecht, Bente; Holm, Søren

    2014-01-01

    Purpose We investigated the use of a simple calibration method to remove bias in previously proposed approaches to image-derived input functions (IDIFs) when used to calculate the metabolic uptake rate of glucose (Km) from dynamic [18F]-FDG PET scans of the thigh. Our objective was to obtain nonbiased, low-variance Km values without blood sampling. Materials and methods We evaluated eight previously proposed IDIF methods. Km values derived from these IDIFs were compared with Km values calculated from the arterial blood samples (gold standard). We used linear regression to extract calibration parameters to remove bias. Following calibration, cross-validation and bootstrapping were used to estimate the mean square error and variance. Results Three of the previously proposed methods failed mainly because of zero-crossings of the IDIF. The remaining five methods were improved by calibration, yielding unbiased Km values. The method with the lowest SD yielded an SD of 0.0017/min – that is, below 10% of the muscle Km value in this study. Conclusion Previously proposed IDIF methods can be improved by using a simple calibration procedure. The calibration procedure may be used in other studies, thus obviating the need for arterial blood sampling, once the calibration parameters have been established in a subgroup of participants. The method has potential for use in other parts of the body as it is robust with regard to partial volume effects. PMID:24335879

  13. Image Derived Input Function for [18F]-FEPPA: Application to Quantify Translocator Protein (18 kDa) in the Human Brain

    PubMed Central

    Mabrouk, Rostom; Rusjan, Pablo M.; Mizrahi, Romina; Jacobs, Mark F.; Koshimori, Yuko; Houle, Sylvain; Ko, Ji Hyun; Strafella, Antonio P.

    2014-01-01

    In [18F]-FEPPA positron emission topography (PET) imaging, automatic blood sampling system (ABSS) is currently the gold standard to obtain the blood time activity curve (TAC) required to extract the input function (IF). Here, we compare the performance of two image-based methods of IF extraction to the ABSS gold standard method for the quantification of translocator protein (TSPO) in the human brain. The IFs were obtained from a direct delineation of the internal carotid signal (CS) and a new concept of independent component analysis (ICA). PET scans were obtained from 18 healthy volunteers. The estimated total distribution volume (VT) by CS-IF and ICA-IF were compared to the reference VT obtained by ABSS-IF in the frontal and temporal cortex, cerebellum, striatum and thalamus regions. The VT values estimated using ICA-IF were more reliable than CS-IF for all brain regions. Specifically, the slope regression in the frontal cortex with ICA-IF was r2?=?0.91 (p<0.05), and r2?=?0.71 (p<0.05) using CS-IF. PMID:25549260

  14. Input design for identification of aircraft stability and control derivatives

    NASA Technical Reports Server (NTRS)

    Gupta, N. K.; Hall, W. E., Jr.

    1975-01-01

    An approach for designing inputs to identify stability and control derivatives from flight test data is presented. This approach is based on finding inputs which provide the maximum possible accuracy of derivative estimates. Two techniques of input specification are implemented for this objective - a time domain technique and a frequency domain technique. The time domain technique gives the control input time history and can be used for any allowable duration of test maneuver, including those where data lengths can only be of short duration. The frequency domain technique specifies the input frequency spectrum, and is best applied for tests where extended data lengths, much longer than the time constants of the modes of interest, are possible. These technqiues are used to design inputs to identify parameters in longitudinal and lateral linear models of conventional aircraft. The constraints of aircraft response limits, such as on structural loads, are realized indirectly through a total energy constraint on the input. Tests with simulated data and theoretical predictions show that the new approaches give input signals which can provide more accurate parameter estimates than can conventional inputs of the same total energy. Results obtained indicate that the approach has been brought to the point where it should be used on flight tests for further evaluation.

  15. Position Estimation Using Image Derivative

    NASA Technical Reports Server (NTRS)

    Mortari, Daniele; deDilectis, Francesco; Zanetti, Renato

    2015-01-01

    This paper describes an image processing algorithm to process Moon and/or Earth images. The theory presented is based on the fact that Moon hard edge points are characterized by the highest values of the image derivative. Outliers are eliminated by two sequential filters. Moon center and radius are then estimated by nonlinear least-squares using circular sigmoid functions. The proposed image processing has been applied and validated using real and synthetic Moon images.

  16. Hybrid image and blood sampling input function for quantification of small animal dynamic PET data.

    PubMed

    Shoghi, Kooresh I; Welch, Michael J

    2007-11-01

    We describe and validate a hybrid image and blood sampling (HIBS) method to derive the input function for quantification of microPET mice data. The HIBS algorithm derives the peak of the input function from the image, which is corrected for recovery, while the tail is derived from 5 to 6 optimally placed blood sampling points. A Bezier interpolation algorithm is used to link the rightmost image peak data point to the leftmost blood sampling point. To assess the performance of HIBS, 4 mice underwent 60-min microPET imaging sessions following a 0.40-0.50-mCi bolus administration of 18FDG. In total, 21 blood samples (blood-sampled plasma time-activity curve, bsPTAC) were obtained throughout the imaging session to compare against the proposed HIBS method. MicroPET images were reconstructed using filtered back projection with a zoom of 2.75 on the heart. Volumetric regions of interest (ROIs) were composed by drawing circular ROIs 3 pixels in diameter on 3-4 transverse planes of the left ventricle. Performance was characterized by kinetic simulations in terms of bias in parameter estimates when bsPTAC and HIBS are used as input functions. The peak of the bsPTAC curve was distorted in comparison to the HIBS-derived curve due to temporal limitations and delay in blood sampling, which affected the rates of bidirectional exchange between plasma and tissue. The results highlight limitations in using bsPTAC. The HIBS method, however, yields consistent results, and thus, is a substitute for bsPTAC. PMID:17998103

  17. Approach for Input Uncertainty Propagation and Robust Design in CFD Using Sensitivity Derivatives

    NASA Technical Reports Server (NTRS)

    Putko, Michele M.; Taylor, Arthur C., III; Newman, Perry A.; Green, Lawrence L.

    2002-01-01

    An implementation of the approximate statistical moment method for uncertainty propagation and robust optimization for quasi 3-D Euler CFD code is presented. Given uncertainties in statistically independent, random, normally distributed input variables, first- and second-order statistical moment procedures are performed to approximate the uncertainty in the CFD output. Efficient calculation of both first- and second-order sensitivity derivatives is required. In order to assess the validity of the approximations, these moments are compared with statistical moments generated through Monte Carlo simulations. The uncertainties in the CFD input variables are also incorporated into a robust optimization procedure. For this optimization, statistical moments involving first-order sensitivity derivatives appear in the objective function and system constraints. Second-order sensitivity derivatives are used in a gradient-based search to successfully execute a robust optimization. The approximate methods used throughout the analyses are found to be valid when considering robustness about input parameter mean values.

  18. Effects of Ground Motion Input on the Derived Fragility Functions: Case study of 2010 Haiti Earthquake

    NASA Astrophysics Data System (ADS)

    Hancilar, Ufuk; Harmandar, Ebru; Çakti, Eser

    2014-05-01

    Empirical fragility functions are derived by statistical processing of the data on: i) Damaged and undamaged buildings, and ii) Ground motion intensity values at the buildings' locations. This study investigates effects of different ground motion inputs on the derived fragility functions. The previously constructed fragility curves (Hancilar et al. 2013), which rely on specific shaking intensity maps published by the USGS after the 2010 Haiti Earthquake, are compared with the fragility functions computed in the present study. Building data come from field surveys of 6,347 buildings that are grouped with respect to structural material type and number of stories. For damage assessment, the European Macroseismic Scale (EMS-98) damage grades are adopted. The simplest way to account for the variability in ground motion input could have been achieved by employing different ground motion prediction equations (GMPEs) and their standard variations. However, in this work, we prefer to rely on stochastically simulated ground motions of the Haiti earthquake. We employ five different source models available in the literature and calculate the resulting strong ground motion in time domain. In our simulations we also consider the local site effects by published studies on NEHRP site classes and micro-zoning maps of the city of Port-au-Prince. We estimate the regional distributions from the waveforms simulated at the same coordinates that we have damage information from. The estimated spatial distributions of peak ground accelerations and velocities, PGA and PGV respectively, are then used as input to fragility computations. The results show that changing the ground motion input causes significant variability in the resulting fragility functions.

  19. Interesting Problems in PET Imaging Estimating the Input Function for a Human

    E-print Network

    Renaut, Rosemary

    Interesting Problems in PET Imaging Estimating the Input Function for a Human Brain FDG-PET Study University and Dr. Kewei Chen Banner Good Samaritan PET Center, Phoenix Supported by: Arizona Alzheimer the input function. 3. A Novel Simultaneous-Estimate Algorithm 4. Results of the Novel Simultaneous

  20. Automated Computer Input Of Paperwritten ECG Records By Image Analysis

    NASA Astrophysics Data System (ADS)

    Haenel, S.

    1982-11-01

    Further development of automated ECG classification requires computer internal representation of well diagnosed ECG of clinical archives, but those ECG are mainly present as paper recorded charts. For chart digitization a high resolution TV camera, connected with digital computer and a soft-ware package for automated image pro-cessing, adapted to the special properties of paper recorded ECG signals is usable. An adapted image processing scheme consists of the following steps: After reconstruction of the lost zero voltage by local filtering of horizontal sections of ECG signal, convex contours of the traces are recognized by gradients. The recognition procedure ensures true acquisition of ECG signal also in the critical ranges of peaks. Full chart length is processed by several frames scanned in particular overlay and connected after curve extraction by a fast correlation method. The result of image processing is an internal representation of paperwritten ECG records, compatible with the electronical ECG recording format.

  1. Use of Ra isotopes to deduce rapid transfer of sediment-derived inputs off Kerguelen

    NASA Astrophysics Data System (ADS)

    Sanial, V.; van Beek, P.; Lansard, B.; Souhaut, M.; Kestenare, E.; d'Ovidio, F.; Zhou, M.; Blain, S.

    2015-03-01

    The Southern Ocean is known to be the largest high-nutrient, low-chlorophyll (HNLC) region of the global ocean due to iron limitation. However, a large phytoplankton bloom develops annually downstream of the Kerguelen Islands, a bloom which is sustained partly by iron released from the sediments deposited onto the shelves. In the framework of the KEOPS-2 project, we used radium isotopes (224Ra, T1/2 = 3.66 d; 223Ra, T1/2 = 11.4 d; 228Ra, T1/2 = 5.75 yr) to provide information on the origin of iron fertilization and on the timescales of the transfer of sediment-derived inputs (including iron and other micronutrients) towards offshore waters. Significant 224Ra and 223Ra activities were found in the near vicinity of the Kerguelen Islands, in agreement with the short half-lives of these isotopes. Significant 224Ra and 223Ra activities were also detected up to 200 km downstream of the islands and more unexpectedly in offshore waters south of the polar front. These observations thus clearly indicate (i) that the sediment-derived inputs are rapidly transferred towards offshore waters (on timescales on the order of several days up to several weeks) and (ii) that the polar front is not a physical barrier for the chemical elements released from the sediments of the Kerguelen Plateau. The Ra data set suggests that iron and other micronutrients released by the shelves of the Kerguelen Islands may contribute to fueling the phytoplankton bloom downstream of the islands, despite the presence of the polar front. However, the heterogeneous distribution of the 224Ra and 223Ra activities in surface waters suggests that this supply across the front is not a continuous process but rather a process that is highly variable in space and time.

  2. Use of Ra isotopes to deduce rapid transfer of sediment-derived inputs off Kerguelen

    NASA Astrophysics Data System (ADS)

    Sanial, V.; van Beek, P.; Lansard, B.; Souhaut, M.; Kestenare, E.; d'Ovidio, F.; Zhou, M.; Blain, S.

    2014-09-01

    The Southern Ocean is known as the largest High-Nutrient, Low-Chlorophyll (HNLC) region of the global ocean due to iron limitation. However, a large phytoplankton bloom develops annually downstream of the Kerguelen Islands, which is sustained partly by iron released from the sediments deposited onto the margins. In the framework of the KEOPS-2 project, we used radium isotopes (224Ra, T1/2 = 3.66 d; 223Ra, T1/2 = 11.4 d; 228Ra, T1/2 = 5.75 yr) to provide information on the origin of iron fertilization and on the timescales of the transfer of sediment-derived inputs (including iron and other micronutrients) towards offshore waters. Significant 223Ra and 223Ra activities were found in the near vicinity of the Kerguelen Islands, in agreement with the short half-lives of these isotopes. Significant 224Ra and 223Ra activities were also detected up to 200 km downstream of the islands and more unexpectedly in offshore waters south of the Polar Front. These observations thus clearly indicate (i) that the sediment-derived inputs are rapidly transferred towards offshore waters (on timescales in the order of several days up to several weeks) and (ii) that the Polar Front is not a physical barrier for the chemical elements released from the sediments of Kerguelen Plateau. The Ra dataset suggests that iron and other micronutrients released by the shallow sediments of the Kerguelen margins may contribute to fuel the phytoplankton bloom downstream of the islands, despite the presence of the Polar Front. However, the heterogeneous distribution of the 224Ra and 223Ra activities in surface waters suggests that this supply across the front is not a continuous process, but rather a process that is highly variable in space and time.

  3. Maximum likelihood identification and optimal input design for identifying aircraft stability and control derivatives

    NASA Technical Reports Server (NTRS)

    Stepner, D. E.; Mehra, R. K.

    1973-01-01

    A new method of extracting aircraft stability and control derivatives from flight test data is developed based on the maximum likelihood cirterion. It is shown that this new method is capable of processing data from both linear and nonlinear models, both with and without process noise and includes output error and equation error methods as special cases. The first application of this method to flight test data is reported for lateral maneuvers of the HL-10 and M2/F3 lifting bodies, including the extraction of stability and control derivatives in the presence of wind gusts. All the problems encountered in this identification study are discussed. Several different methods (including a priori weighting, parameter fixing and constrained parameter values) for dealing with identifiability and uniqueness problems are introduced and the results given. The method for the design of optimal inputs for identifying the parameters of linear dynamic systems is also given. The criterion used for the optimization is the sensitivity of the system output to the unknown parameters. Several simple examples are first given and then the results of an extensive stability and control dervative identification simulation for a C-8 aircraft are detailed.

  4. Shelf-derived iron inputs drive biological productivity in the southern Drake Passage

    NASA Astrophysics Data System (ADS)

    Dulaiova, H.; Ardelan, M. V.; Henderson, P. B.; Charette, M. A.

    2009-12-01

    In the Southern Ocean near the Antarctic Peninsula, Antarctic Circumpolar Current (ACC) fronts interact with shelf waters facilitating lateral transport of shelf-derived components such as iron into high-nutrient offshore regions. To trace these shelf-derived components and estimate lateral mixing rates of shelf water, we used naturally occurring radium isotopes. Short-lived radium isotopes were used to quantify the rates of shelf water entrainment while Fe/228Ra ratios were used to calculate the Fe flux. In the summer of 2006 we found rapid mixing and significant lateral iron export, namely, a dissolved iron flux of 1.1 × 105 mol d-1 and total acid leachable iron flux of 1.1 × 106 mol d-1 all of which is transported in the mixed layer from the shelf region offshore. This dissolved iron flux is significant, especially considering that the bloom observed in the offshore region (0.5-2 mg chl a m-3) had an iron demand of 1.1 to 4 × 105 mol Fe. Net vertical export fluxes of particulate Fe derived from 234Th/238U disequilibrium and Fe/234Th ratios accounted for only about 25% of the dissolved iron flux. On the other hand, vertical upward mixing of iron rich deeper waters provided only 7% of the lateral dissolved iron flux. We found that similarly to other studies in iron-fertilized regions of the Southern Ocean, lateral fluxes overwhelm vertical inputs and vertical export from the water column and support significant phytoplankton blooms in the offshore regions of the Drake Passage.

  5. Fluorescein Derivatives in Intravital Fluorescence Imaging

    PubMed Central

    Robertson, Thomas A.; Bunel, Florestan; Roberts, Michael S.

    2013-01-01

    Intravital fluorescence microscopy enables the direct imaging of fluorophores in vivo and advanced techniques such as fluorescence lifetime imaging (FLIM) enable the simultaneous detection of multiple fluorophores. Consequently, it is now possible to record distribution and metabolism of a chemical in vivo and to optimise the delivery of fluorophores in vivo. Recent clinical applications with fluorescein and other intravital fluorescent stains have occurred in neurosurgery, dermatology [including photodynamic therapy (PDT)] and endomicroscopy. Potential uses have been identified in periodontal disease, skin graft and cancer surgery. Animal studies have demonstrated that diseased tissue can be specifically stained with fluorophore conjugates. This review focuses on the fluorescein derived fluorophores in common clinical use and provides examples of novel applications from studies in tissue samples. PMID:24709799

  6. Using Whole-House Field Tests to Empirically Derive Moisture Buffering Model Inputs

    SciTech Connect

    Woods, J.; Winkler, J.; Christensen, D.; Hancock, E.

    2014-08-01

    Building energy simulations can be used to predict a building's interior conditions, along with the energy use associated with keeping these conditions comfortable. These models simulate the loads on the building (e.g., internal gains, envelope heat transfer), determine the operation of the space conditioning equipment, and then calculate the building's temperature and humidity throughout the year. The indoor temperature and humidity are affected not only by the loads and the space conditioning equipment, but also by the capacitance of the building materials, which buffer changes in temperature and humidity. This research developed an empirical method to extract whole-house model inputs for use with a more accurate moisture capacitance model (the effective moisture penetration depth model). The experimental approach was to subject the materials in the house to a square-wave relative humidity profile, measure all of the moisture transfer terms (e.g., infiltration, air conditioner condensate) and calculate the only unmeasured term: the moisture absorption into the materials. After validating the method with laboratory measurements, we performed the tests in a field house. A least-squares fit of an analytical solution to the measured moisture absorption curves was used to determine the three independent model parameters representing the moisture buffering potential of this house and its furnishings. Follow on tests with realistic latent and sensible loads showed good agreement with the derived parameters, especially compared to the commonly-used effective capacitance approach. These results show that the EMPD model, once the inputs are known, is an accurate moisture buffering model.

  7. Learning Non-linear SVM in Input Space for Image Classification

    E-print Network

    Paris-Sud XI, Université de

    1 Learning Non-linear SVM in Input Space for Image Classification Gaurav Sharma, Fr´ed´eric Jurie for learning non-linear support vector machine (SVM) corresponding to commonly used kernels in computer vision performance w.r.t. kernel SVM and recent explicit feature mapping method while being significantly faster

  8. Java Library for Input and Output of Image Data and Metadata

    NASA Technical Reports Server (NTRS)

    Deen, Robert; Levoe, Steven

    2003-01-01

    A Java-language library supports input and output (I/O) of image data and metadata (label data) in the format of the Video Image Communication and Retrieval (VICAR) image-processing software and in several similar formats, including a subset of the Planetary Data System (PDS) image file format. The library does the following: It provides low-level, direct access layer, enabling an application subprogram to read and write specific image files, lines, or pixels, and manipulate metadata directly. Two coding/decoding subprograms ("codecs" for short) based on the Java Advanced Imaging (JAI) software provide access to VICAR and PDS images in a file-format-independent manner. The VICAR and PDS codecs enable any program that conforms to the specification of the JAI codec to use VICAR or PDS images automatically, without specific knowledge of the VICAR or PDS format. The library also includes Image I/O plugin subprograms for VICAR and PDS formats. Application programs that conform to the Image I/O specification of Java version 1.4 can utilize any image format for which such a plug-in subprogram exists, without specific knowledge of the format itself. Like the aforementioned codecs, the VICAR and PDS Image I/O plug-in subprograms support reading and writing of metadata.

  9. Effectiveness of soft classification approaches as inputs for super resolution mapping of Hyperion image: a study on Peechi Reservoir, south India

    NASA Astrophysics Data System (ADS)

    Shanmuga Priyaa, S.; Sanjeevi, S.

    2014-11-01

    Image classification has evolved from per-pixel to sub-pixel and from sub-pixel to super resolution mapping approaches. Super-resolution mapping (SRM) is a technique which allows mapping at the sub-pixel scale. Super-resolution mapping proves to be the better approach for the accurate classification of coarse spatial resolution images and to resolve mixed pixels in the boundary of such images. The accuracy of the super-resolved output depends on the input derived from the soft classification technique. This paper aims to compare the potential of support vector machine (SVM), spectral angle mapper (SAM) and linear spectral unmixing (LSU) as inputs for super-resolution mapping. The fraction image, distance measure image and probability image obtained from linear spectral unmixing, spectral angle mapper and support vector machine respectively are used as an input for super resolution mapping designed on Hopfield Neural Network (HNN) for the Hyperion image of Peechi reservoir, south India. Effectiveness of the inputs is evaluated by estimating the water-spread area of the Peechi reservoir from each of the outputs. The results indicate that the accuracy of any super-resolution approach depends on the inputs from the soft classification approaches. The accuracy of the water spread area estimated from the classified outputs is 95.9%, 96.6% and 99.7% from LSU, SAM and SVM respectively as inputs for the SRM method. Thus, the HNN based SRM method proves to be better when the soft classification input is from SVM.

  10. Regional biomass and leaf-area estimates derived from satellite imagery as inputs to spatial trace-gas flux models for arctic tundra

    SciTech Connect

    Shippert, M.M.; Walker, D.A.; Auerbach, N.A.; Lewis, B.E. (Univ. of Colorado, Boulder, CO (United States))

    1994-06-01

    Reflectance spectra, leaf area index (LAI), and live biomass measurements were collected for 60 plots near Toolik Lake and Imnavait Creek, Alaska during July and August, 1993. Normalized difference vegetation indices (NDVI) were calculated from the reflectance spectra. NDVI was found to be highly correlated to both LAI and biomass. These relationships have been seen in temperate ecosystems, but have never been tested in Arctic tundra previous to this study. In addition, a clear relationship is seen between NDVI values and pH and moisture. Acidic plots have much higher NDVI values than non-acidic plots, while moist plots have high NDVI values relative to dry and wet plots. The average field NDVI measurements for major physiognomic categories were compared to average NDVI values for the same categories derived from a SPOT multispectral satellite image of the area. These values were also found to be highly correlated. However, field NDVI values were consistently about 40% higher than SPOT NDVI values. Possible explanations for this consistent trend include effects of low sun angle in the Arctic in combination with relatively high view angle of the SPOT sensor. Using the regression equations for the above relationships, biomass and LAI images were calculated from the SPOT image. The resulting images show expected trends in the LAI and biomass across the landscape. The image of biomass will be used as an input to a spatial model of methane emissions for the Alaskan Arctic. Another key input variable to the methane model will be soil moisture. Alternative image processing methods and/or radar images will be used to derive this important variable.

  11. Temporal structure of receptor neuron input to the olfactory bulb imaged in behaving rats.

    PubMed

    Carey, Ryan M; Verhagen, Justus V; Wesson, Daniel W; Pírez, Nicolás; Wachowiak, Matt

    2009-02-01

    The dynamics of sensory input to the nervous system play a critical role in shaping higher-level processing. In the olfactory system, the dynamics of input from olfactory receptor neurons (ORNs) are poorly characterized and depend on multiple factors, including respiration-driven airflow through the nasal cavity, odorant sorption kinetics, receptor-ligand interactions between odorant and receptor, and the electrophysiological properties of ORNs. Here, we provide a detailed characterization of the temporal organization of ORN input to the mammalian olfactory bulb (OB) during natural respiration, using calcium imaging to monitor ORN input to the OB in awake, head-fixed rats expressing odor-guided behaviors. We report several key findings. First, across a population of homotypic ORNs, each inhalation of odorant evokes a burst of action potentials having a rise time of about 80 ms and a duration of about 100 ms. This rise time indicates a relatively slow, progressive increase in ORN activation as odorant flows through the nasal cavity. Second, the dynamics of ORN input differ among glomeruli and for different odorants and concentrations, but remain reliable across successive inhalations. Third, inhalation alone (in the absence of odorant) evokes ORN input to a significant fraction of OB glomeruli. Finally, high-frequency sniffing of odorant strongly reduces the temporal coupling between ORN inputs and the respiratory cycle. These results suggest that the dynamics of sensory input to the olfactory system may play a role in coding odor information and that, in the awake animal, strategies for processing odor information may change as a function of sampling behavior. PMID:19091924

  12. Derivative encoding for parallel magnetic resonance imaging a

    PubMed Central

    Shen, Jun

    2011-01-01

    Purpose: To introduce a linear shift-invariant relationship between the partial derivatives of k space signals acquired using multichannel receive coils and to demonstrate that k space derivatives can be used for image unwrapping.Methods: Fourier transform of k space derivatives contains information on the spatial origins of aliased pixels; therefore, images can be reconstructed by k space derivatives. Fully sampled phantom and brain images acquired at 3 T using a standard eight channel receive coil were used to validate the k space derivatives theorem by unwrapping aliased images.Results: Derivative encoding leads to new methods for parallel imaging reconstruction in both k space and image domains. Noise amplification in sensitivity encoding image reconstruction, which is considered to produce the optimal SNR, can be further reduced using k space derivative encoding without making any assumptions on the characteristics of the images to be reconstructed.Conclusions: This work demonstrated that the partial derivative of the k space signal acquired from one coil with respect to one direction can be expressed as a sum of partial derivatives of signals from multiple coils with respect to the perpendicular k space direction(s). This relationship between the partial derivatives of k space signals is linear and shift-invariant in the Cartesian coordinate system. PMID:21992376

  13. Minimally Invasive Method of Determining Blood Input Function from PET Images in Rodents

    Microsoft Academic Search

    Joonyoung Kim; Pilar Herrero; Terry Sharp; Richard Laforest; Douglas J. Rowland; Yuan-Chuan Tai; Jason S. Lewis; Michael J. Welch

    2006-01-01

    For cardiovascular research on rodents, small-animal PET has limitations because of the inherent spatial resolution of the sys- tem and because of cardiac motion. A factor analysis (FA) tech- nique for extracting the blood input function and myocardial time-activity curve from dynamic small-animal PET images of the rodent heart has been implemented to overcome these limi- tations. Methods: Six Sprague-Dawley

  14. Extraction of an input function from dynamic micro-PET images using wavelet packet based sub-band decomposition independent component analysis.

    PubMed

    Lee, Jhih-Shian; Su, Kuan-Hao; Chang, Wen-Yuan; Chen, Jyh-Cheng

    2012-11-15

    Positron emission tomography (PET) can be used to quantify physiological parameters. However to perform quantification requires that an input function is measured, namely a plasma time activity curve (TAC). Image-derived input functions (IDIFs) are attractive because they are noninvasive and nearly no blood loss is involved. However, the spatial resolution and the signal to noise ratio (SNR) of PET images are low, which degrades the accuracy of IDIFs. The objective of this study was to extract accurate input functions from microPET images with zero or one plasma sample using wavelet packet based sub-band decomposition independent component analysis (WP SDICA). Two approaches were used in this study. The first was the use of simulated dynamic rat images with different spatial resolutions and SNRs, and the second was the use of dynamic images of eight Sprague-Dawley rats. We also used a population-based input function and a fuzzy c-means clustering approach and compared their results with those obtained by our method using normalized root mean square errors, area under curve errors, and correlation coefficients. Our results showed that the accuracy of the one-sample WP SDICA approach was better than the other approaches using both simulated and realistic comparisons. The errors in the metabolic rate, as estimated by one-sample WP SDICA, were also the smallest using our approach. PMID:22892332

  15. Historical changes in terrestrially derived organic carbon inputs to Louisiana continental margin sediments over the past 150 years

    Microsoft Academic Search

    Troy P. Sampere; Thomas S. Bianchi; Mead A. Allison

    2011-01-01

    Major rivers (and associated deltaic environments) provide the dominant pathway for the input of terrestrial-derived organic carbon in sediments (TOCT) to the ocean. Natural watershed processes and land-use changes are important in dictating the amount and character of carbon being buried on continental margins. Seven core sites were occupied on the Louisiana continental margin aboard the R\\/V Pelican in July

  16. Shelf-derived iron inputs drive biological productivity in the southern Drake Passage

    E-print Network

    transport of shelf-derived components such as iron into high-nutrient offshore regions. To trace these shelf-derived biolimiting trace elements from the Bellinghausen Sea, Bransfield Strait and Weddell Sea mix with high-nutrient Peninsula, Antarctic Circumpolar Current (ACC) fronts interact with shelf waters facilitating lateral

  17. Derivative hyperspectral image analysis for land use classification

    NASA Astrophysics Data System (ADS)

    Tsai, Fu-An

    As hyperspectral remote sensing data become commonly available, researchers need an effective tool specifically designed for analyzing this new type of data. Derivative analysis has been proved a useful tool capable of detecting subtle information from hyperspectral data sets. However, there are no systematic procedures for effectively applying derivative analysis to remote sensing hyperspectral images yet. This research developed a systematic procedure for using derivative analysis to help improve supervised classification of hyperspectral images. The algorithm allows investigators to identify derivative features better separating target classes according to the Jeffries-Matusita distances between classes. These features can be added into the classification image in order to improve the classification result. A maximum likelihood classification for vegetation was used as an example in this research. It demonstrated the effectiveness of using derivatives to detect useful information that might be lost during feature reduction operations. Classification accuracies of classes that were poorly classified in a 10-band principal component image gradually improved as more appropriate derivative features were extracted from the original image and appended to the base image. With the data set used in this study, derivative analysis did not generally provide a better performance than principal component analysis, but it may be suitable for some data sets and applications. The procedure developed in this research can be used as a starting point for subsequently designing an advanced system to systematically analyze hyperspectral images for remote sensing applications.

  18. Reducing input data via image categorization to improve the speed of copyright content management systems

    NASA Astrophysics Data System (ADS)

    Ikeda, Kanami; Watanabe, Eriko

    2015-03-01

    An optical correlator has the advantage of high data transfer speed and parallel operation. However, in copyright content management systems (CCMSs), the numerous video files that need to be downloaded from the Internet and input to the optical correlator constitute a bottleneck. This paper proposes an image categorization method for CCMSs that uses the difference in the color features between animation and live-action images to remove this bottleneck and increase the speed of CCMSs. The results of experiments conducted indicate that the proposed method achieves a live-action video true rejection rate of 86.7 % and an animation video false rejection rate of 13.3 %. This indicates that the proposed method can improve the overall speed of a CCMS more than twice the original speed.

  19. A Simplified Derivation of Frei's Histogram Hyperbolization for Image Enhancement

    Microsoft Academic Search

    Paul J. Nahin

    1979-01-01

    Frei has recently introduced a new technique (histogram hyperbolization) for image enhancement by the manipulation of the picture brightness levels. An alternative derivation of Frei's result, both simpler and more general, is presented.

  20. Light field creating and imaging with different order intensity derivatives

    NASA Astrophysics Data System (ADS)

    Wang, Yu; Jiang, Huan

    2014-10-01

    Microscopic image restoration and reconstruction is a challenging topic in the image processing and computer vision, which can be widely applied to life science, biology and medicine etc. A microscopic light field creating and three dimensional (3D) reconstruction method is proposed for transparent or partially transparent microscopic samples, which is based on the Taylor expansion theorem and polynomial fitting. Firstly the image stack of the specimen is divided into several groups in an overlapping or non-overlapping way along the optical axis, and the first image of every group is regarded as reference image. Then different order intensity derivatives are calculated using all the images of every group and polynomial fitting method based on the assumption that the structure of the specimen contained by the image stack in a small range along the optical axis are possessed of smooth and linear property. Subsequently, new images located any position from which to reference image the distance is ?z along the optical axis can be generated by means of Taylor expansion theorem and the calculated different order intensity derivatives. Finally, the microscopic specimen can be reconstructed in 3D form using deconvolution technology and all the images including both the observed images and the generated images. The experimental results show the effectiveness and feasibility of our method.

  1. Input of river-derived sediment to the New Zealand continental shelf: II mineralogy and composition

    NASA Astrophysics Data System (ADS)

    Churchman, G. J.; Hunt, J. L.; Glasby, G. P.; Renner, R. M.; Griffiths, G. A.

    1988-10-01

    Clay mineralogies and elemental compositions of river-borne sediments from New Zealand were examined as indicators of likely sources of the lithogenous component of sediments on the continental shelf. Relative occurrences of kaolin and smectite enabled the rivers to be fitted into three main groups. These correspond closely with geography as follows: (1) most of the rivers from North Island; (2) all the rivers from the north-east coast of South Island; (3) most of the rivers from the remainder of South Island. Elemental analyses of their sediments also led to a geographical grouping of rivers. Six main groups resulted from a Q-mode cluster analysis of elemental compositions. These were: the northernmost river (Wairoa River); the east coast of North Island; the west coast of North Island; the east coast of South Island; the south-east and west coasts of South Island; the west coast of South Island. There is substantial overlap between the groupings by clay mineralogy and by composition. The results can be interpreted mainly in terms of the geologies of source areas. Exceptions to regional trends reflect either an unusual geology in the source areas or low sediment loads, where soils contribute significantly to the sediments. The terrigenous component of offshore sediments and New Zealand riverine sediments have similar compositions, suggesting that the former are derived in a relatively unmodified form from riverine sediments.

  2. A text input system developed by using lips image recognition based LabVIEW for the seriously disabled.

    PubMed

    Chen, S C; Shao, C L; Liang, C K; Lin, S W; Huang, T H; Hsieh, M C; Yang, C H; Luo, C H; Wuo, C M

    2004-01-01

    In this paper, we present a text input system for the seriously disabled by using lips image recognition based on LabVIEW. This system can be divided into the software subsystem and the hardware subsystem. In the software subsystem, we adopted the technique of image processing to recognize the status of mouth-opened or mouth-closed depending the relative distance between the upper lip and the lower lip. In the hardware subsystem, parallel port built in PC is used to transmit the recognized result of mouth status to the Morse-code text input system. Integrating the software subsystem with the hardware subsystem, we implement a text input system by using lips image recognition programmed in LabVIEW language. We hope the system can help the seriously disabled to communicate with normal people more easily. PMID:17271421

  3. Methods for edge enhancement in color images based on derivative operations

    NASA Astrophysics Data System (ADS)

    Flores, Jorge L.; Ferrari, José A.; Fernández, Ariel; Alonso, Julia R.; Ayubi, Gastón A.; Di Martino, J. Matías

    2012-10-01

    We present optical methods for edge enhancement in color images using optical derivative operations (first order derivative and Laplacian operator). The proposed methods is based on the polarization properties of liquid-crystal displays (LCD) and on the capacity of digital micro mirror devices to generate a (positive) copy of the digital image used as input, and simultaneously a complementary color replica of it. In the proposed optical setup the negative and positive replicas are at the same time imagined across a plane. First we analyzed the case when the negative replica has a lateral differential displacement relative to the original one; an image with enhanced first derivatives along a specific direction is obtained. In the case when the negative replica is low-pass filtered, one obtains the Laplacian of the original image. Unlike Fourier, our proposal works with incoherent illumination and does not require precise alignment, and thus, it could be a useful tool for edge extraction/enhancement in large images in real-time applications. Validation experiments are presented.

  4. An improved temperature index model for alpine glaciers using derived degree-day factors from climatic inputs

    NASA Astrophysics Data System (ADS)

    Keeler, D. G.; Havens, A. P.; Rupper, S.; Christensen, W. F.

    2013-12-01

    Glacier melt rates are strongly affected by minor perturbations in climatic systems. Quantifying changes in glacier melt rates is therefore important, particularly in areas where melt-water contributes to hydroelectric power generation, irrigation, or flood risks. Several methods currently exist for modeling glacier melt rates, but one widely used method is temperature index modeling, also called positive degree-day modeling. This model is often applied due to its simplicity and small number of input variables, but it still depends on an empirically-measured scaling constant (the degree-day factor). These degree-day factors can vary by a factor of five from one glacier to the next, complicating the applicability of the approach to new regions, or to different time periods. Previous work suggests the degree-day factor may be a function of the surface albedo, solar radiation, and near-surface air temperature. Thus, it is possible the degree-day factor itself is predictable. In this study we present a method to derive these melt factors directly from easily obtained climatic variables, thus allowing for the ready application of temperature index modeling to a much wider suite of glaciers with greater accuracy. We used a full energy-balance model to calculate possible degree-day factors over the full range of climate conditions commonly encountered with alpine glaciers. We then constructed a statistical emulator (a linear model which considers numerous interactions and polynomial effects) using select climate variables (insolation, positive degree-days, and albedo) as inputs. The statistical model is tuned using the energy-balance output as training data. The model skill will be tested against a suite of empirically-derived degree-day factors. These results would allow for the application of more accurate glacier melt models with quantified uncertainties to under-sampled glacial regions and paleoclimate reconstructions.

  5. A comparison of individual and population-derived vascular input functions for quantitative DCE-MRI in rats.

    PubMed

    Hormuth, David A; Skinner, Jack T; Does, Mark D; Yankeelov, Thomas E

    2014-05-01

    Dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) can quantitatively and qualitatively assess physiological characteristics of tissue. Quantitative DCE-MRI requires an estimate of the time rate of change of the concentration of the contrast agent in the blood plasma, the vascular input function (VIF). Measuring the VIF in small animals is notoriously difficult as it requires high temporal resolution images limiting the achievable number of slices, field-of-view, spatial resolution, and signal-to-noise. Alternatively, a population-averaged VIF could be used to mitigate the acquisition demands in studies aimed to investigate, for example, tumor vascular characteristics. Thus, the overall goal of this manuscript is to determine how the kinetic parameters estimated by a population based VIF differ from those estimated by an individual VIF. Eight rats bearing gliomas were imaged before, during, and after an injection of Gd-DTPA. K(trans), ve, and vp were extracted from signal-time curves of tumor tissue using both individual and population-averaged VIFs. Extended model voxel estimates of K(trans) and ve in all animals had concordance correlation coefficients (CCC) ranging from 0.69 to 0.98 and Pearson correlation coefficients (PCC) ranging from 0.70 to 0.99. Additionally, standard model estimates resulted in CCCs ranging from 0.81 to 0.99 and PCCs ranging from 0.98 to 1.00, supporting the use of a population based VIF if an individual VIF is not available. PMID:24556502

  6. Derivate

    NSDL National Science Digital Library

    2010-01-01

    In this activity, students input functions in order to calculate the derivative and tangent line of that function. This activity allows students to explore tangent lines of various functions. This activity includes supplemental materials, including background information about the topics covered, a description of how to use the application, and exploration questions for use with the java applet.

  7. Subthreshold membrane currents confer distinct tuning properties that enable neurons to encode the integral or derivative of their input

    PubMed Central

    Ratté, Stéphanie; Lankarany, Milad; Rho, Young-Ah; Patterson, Adam; Prescott, Steven A.

    2015-01-01

    Neurons rely on action potentials, or spikes, to encode information. But spikes can encode different stimulus features in different neurons. We show here through simulations and experiments how neurons encode the integral or derivative of their input based on the distinct tuning properties conferred upon them by subthreshold currents. Slow-activating subthreshold inward (depolarizing) current mediates positive feedback control of subthreshold voltage, sustaining depolarization and allowing the neuron to spike on the basis of its integrated stimulus waveform. Slow-activating subthreshold outward (hyperpolarizing) current mediates negative feedback control of subthreshold voltage, truncating depolarization and forcing the neuron to spike on the basis of its differentiated stimulus waveform. Depending on its direction, slow-activating subthreshold current cooperates or competes with fast-activating inward current during spike initiation. This explanation predicts that sensitivity to the rate of change of stimulus intensity differs qualitatively between integrators and differentiators. This was confirmed experimentally in spinal sensory neurons that naturally behave as specialized integrators or differentiators. Predicted sensitivity to different stimulus features was confirmed by covariance analysis. Integration and differentiation, which are themselves inverse operations, are thus shown to be implemented by the slow feedback mediated by oppositely directed subthreshold currents expressed in different neurons. PMID:25620913

  8. Robust multi-scale image matching for deriving ice surface velocity field from sequential satellite images

    Microsoft Academic Search

    Hongxing Liu; Lei Wang; Sheng-Jung Tang; Kenneth C. Jezek

    2012-01-01

    The cross-correlation-based image matching method has been widely used to derive ice surface motion information from sequential satellite images through tracking spatial displacements of surface features over time. However, this conventional method is not adequate for handling areas with a high velocity variation, in which case a large search window has to be specified in order to find the correct

  9. Robust multi-scale image matching for deriving ice surface velocity field from sequential satellite images

    Microsoft Academic Search

    Hongxing Liu; Lei Wang; Sheng-Jung Tang; Kenneth C. Jezek

    2011-01-01

    The cross-correlation-based image matching method has been widely used to derive ice surface motion information from sequential satellite images through tracking spatial displacements of surface features over time. However, this conventional method is not adequate for handling areas with a high velocity variation, in which case a large search window has to be specified in order to find the correct

  10. Thermal imaging for input to terrestrial and planetary thermal models (Invited)

    NASA Astrophysics Data System (ADS)

    Gillespie, A. R.

    2013-12-01

    Multispectral imaging of emitted thermal radiation is used to estimate surface composition, especially of silicate minerals, but the most common use is to estimate surface temperature T. Thermal modeling requires accurate estimation of T, which for many terrestrial and nearly all planetary studies requires measuring radiance L remotely. The key difficulty is that thermal imaging is underdetermined, with 3 atmospheric parameters and n+1 surface parameters where n is the number of channels (i, j...), even if adjacency effects and anisothermal pixels are overlooked. The n unknowns are emissivities ? (i), and if T is to be estimated something about the ? spectrum must generally be known or assumed. Many different algorithms have been devised. If n=1, ? is assumed from laboratory data; if n=2, T for water is proportional to L(i) and L(j)-L(i) (split-window technique), empirically calibrated. One of the benefits of multispectral imaging is that ?(i) can be estimated pixel by pixel, such that T can be recovered with more confidence. Multispectral and hyperspectral data are commonly handled by assuming the maximum value of ?. Under some conditions, two-time imaging can be used assuming that ?(i) is unchanging. Generally, terrestrial atmospheric corrections, instrumental calibration and ? assumptions contribute roughly equally to T inaccuracy of 1-2 K for high spatial resolution data, although for low resolution, restricted atmospheric conditions, and known surface composition this figure can be improved. Peak L occurs at increasing wavenumber as T rises. Thus, T recovery for active volcanoes makes use of midwave (2000-3300 cm-1) or shortwave (3300-10,000 cm-1) rather than longwave thermal infrared (700-1250 cm-1). One complexity is atmospheric variability near active vents; another is the possibility that ? may change as lava cools and the crystallinity of the skin changes (Abtahi et al., 2002). At the other extreme Mars and the icy satellites have low T and therefore lower SNR than warmer targets. This especially is true at night, for example on Mars. Thermal inertia, a measure of the resistance of a surface to changing its T as energy is added or subtracted to it, can be estimated from day-night temperature differences. It can in principle be used to learn something about the porosity, rock/soil ratios, the presence of thin veneers of sand, or other non-compositional characteristics of a surface. Quantitative measures of T, ? and thermal inertia are needed for thermal modeling. However, calculating thermal inertia requires accounting for topography and albedo and is more challenging than just estimating T, and therefore on both Earth and Mars approximations to it are commonly used photointerpretively, just as images of T images and even derived ? are sometimes used photointerpretively also.

  11. Direct Characterization of Arterial Input Functions by Fluorescence Imaging of Exposed Carotid Artery to Facilitate Kinetic Analysis

    PubMed Central

    Elliott, Jonathan T.; Tichauer, Kenneth M.; Samkoe, Kimberley S.; Gunn, Jason R.; Sexton, Kristian J.; Pogue, Brian W.

    2014-01-01

    Purpose With the goal of facilitating tracer kinetic analysis in small-animal planar fluorescence imaging, an experimental method for characterizing tracer arterial input functions is presented. The proposed method involves exposing the common carotid arteries by surgical dissection, which can then be imaged directly during tracer injection and clearance. Procedures Arterial concentration curves of IRDye-700DX-carboxylate, IRDye-800CW-EGF, and IRDye-800CW conjugated to anti-EGFR Affibody are recovered from athymic female mice (n=12) by directly imaging exposed vessels. Images were acquired with two imaging protocols: a slow-kinetics approach (temporal resolution=45 s) to recover the arterial curves from two tracers simultaneously, and a fast-kinetics approach (temporal resolution=500 ms) to characterize the first-pass peak of a single tracer. Arterial input functions obtained by the carotid imaging technique, as well as plasma curves measured by blood sampling were fit with a biexponential pharmacokinetic model. Results Pharmacological fast- and slow-phase rate constants recovered with the proposed method were 0.37±0.26 and 0.007±0.001 min?1, respectively, for the IRDye700DX-C. For the IRDye800CW-EGF, the rate constants were 0.11±0.13 and 0.003±0.002 min?1. These rate constants did not differ significantly from those calculated previously by blood sampling, as determined by an F test; however, the between-subject variability was four times lower for arterial curves recovered using the proposed technique, compared with blood sampling. Conclusions The proposed technique enables the direct characterization of arterial input functions for kinetic analysis. As this method requires no additional instrumentation, it is immediately deployable in commercially available planar fluorescence imaging systems. PMID:24420443

  12. Wh-Questions in Child L2 French: Derivational Complexity and Its Interactions with L1 Properties, Length of Exposure, Age of Exposure, and the Input

    ERIC Educational Resources Information Center

    Prévost, Philippe; Strik, Nelleke; Tuller, Laurie

    2014-01-01

    This study investigates how derivational complexity interacts with first language (L1) properties, second language (L2) input, age of first exposure to the target language, and length of exposure in child L2 acquisition. We compared elicited production of "wh"-questions in French in two groups of 15 participants each, one with L1 English…

  13. On the input-output stability of time-varying nonlinear feedback systems Part one: Conditions derived using concepts of loop gain, conicity, and positivity

    Microsoft Academic Search

    G. Zames

    1966-01-01

    The object of this paper is to outline a stability theory for input-output problems using functional methods. More particularly, the aim is to derive open loop conditions for the boundedness and continuity of feedback systems, without, at the beginning, placing restrictions on linearity or time invariance. It will be recalled that, in the special case of a linear time invariant

  14. Optical encryption in spatially-incoherent light using two LC SLMs for both information input and encryption element imaging

    NASA Astrophysics Data System (ADS)

    Bondareva, Alyona P.; Cheremkhin, Pavel A.; Evtikhiev, Nikolay N.; Krasnov, Vitaly V.; Rodin, Vladislav G.; Starikov, Sergey N.

    2014-10-01

    At present time methods of optical encryption are actively developed. The majority of existing methods of optical encryption use not only light intensity distribution, easily registered with photosensors, but also its phase distribution which require application of complex holographic schemes in conjunction with spatially coherent monochromatic illumination. This leads to complex optical schemes and low decryption quality. To eliminate these disadvantages it is possible to implement optical encryption using spatially incoherent monochromatic illumination which requires registration of light intensity distribution only. Encryption is accomplished by means of optical convolution of image of scene to be encrypted and encryption diffractive optical element (DOE) point spread function (PSF) which serves as encryption key. Encryption process is described as follows. Scene is illuminated with spatially-incoherent monochromatic light. In the absence of encryption DOE lens forms image of scene in photosensor plane. DOE serves as encryption element, its PSF - encryption key. Light passing through DOE forms convolution of object image and DOE PSF. Registered by photosensor convolution is encrypted image. Decryption was conducted numerically on computer by means of inverse filtration with regularization. Kinoforms were used as encryption DOE because they have single diffraction order. Two liquid crystal (LC) spatial light modulators (SLM) were used to implement dynamic digital information input and dynamic encryption key change. As input scene amplitude LC SLM HoloEye LC2002 with 800×600 pixels 32×32 ?m2 and 256 gray levels was used. To image synthesized encryption kinoforms phase LC SLM HoloEye PLUTO VIS with 1920×1080 pixels 8×8 ?m2 and 256 phase levels was used. Set of test images was successfully optically encrypted and then numerically decrypted. Encrypted images contents are hidden. Decrypted images despite quite high noise levels are positively recognizable. Results of optical encryption and numerical decryption are presented.

  15. One goal of examing satellite images is to derive maps of earth Digital Image Classification Has Two Components

    E-print Network

    Frank, Thomas D.

    One goal of examing satellite images is to derive maps of earth #12;Digital Image Classification Image Classification The objective of digital image classification is to partition feature space into decision regions, then to assign pixels in an image to the most likely feature category. #12;By selecting

  16. The least-squares mixing models to generate fraction images derived from remote sensing multispectral data

    Microsoft Academic Search

    Yosio Edemir Shimabukuro; James A. Smith

    1991-01-01

    Constrained-least-squares (CLS) and weighted-least-squares (WLS) mixing models for generating fraction images derived from remote sensing multispectral data are presented. An experiment considering three components within the pixels-eucalyptus, soil (understory), and shade-was performed. The generated fraction images for shade (shade image) derived from these two methods were compared by considering the performance and computer time. The derived shade images are related

  17. Genetic Dissection of Retinal Inputs to Brainstem Nuclei Controlling Image Stabilization

    PubMed Central

    Dhande, Onkar S.; Estevez, Maureen E.; Quattrochi, Lauren E.; El-Danaf, Rana N.; Nguyen, Phong L.

    2013-01-01

    When the head rotates, the image of the visual world slips across the retina. A dedicated set of retinal ganglion cells (RGCs) and brainstem visual nuclei termed the “accessory optic system” (AOS) generate slip-compensating eye movements that stabilize visual images on the retina and improve visual performance. Which types of RGCs project to each of the various AOS nuclei remain unresolved. Here we report a new transgenic mouse line, Hoxd10–GFP, in which the RGCs projecting to all the AOS nuclei are fluorescently labeled. Electrophysiological recordings of Hoxd10–GFP RGCs revealed that they include all three subtypes of On direction-selective RGCs (On–DSGCs), responding to upward, downward, or forward motion. Hoxd10–GFP RGCs also include one subtype of On–Off DSGCs tuned for forward motion. Retrograde circuit mapping with modified rabies viruses revealed that the On–DSGCs project to the brainstem centers involved in both horizontal and vertical retinal slip compensation. In contrast, the On–Off DSGCs labeled in Hoxd10–GFP mice projected to AOS nuclei controlling horizontal but not vertical image stabilization. Moreover, the forward tuned On–Off DSGCs appear physiologically and molecularly distinct from all previously genetically identified On–Off DSGCs. These data begin to clarify the cell types and circuits underlying image stabilization during self-motion, and they support an unexpected diversity of DSGC subtypes. PMID:24198370

  18. Design criteria for a multiple input land use system. [digital image processing techniques

    NASA Technical Reports Server (NTRS)

    Billingsley, F. C.; Bryant, N. A.

    1975-01-01

    A design is presented that proposes the use of digital image processing techniques to interface existing geocoded data sets and information management systems with thematic maps and remote sensed imagery. The basic premise is that geocoded data sets can be referenced to a raster scan that is equivalent to a grid cell data set, and that images taken of thematic maps or from remote sensing platforms can be converted to a raster scan. A major advantage of the raster format is that x, y coordinates are implicitly recognized by their position in the scan, and z values can be treated as Boolean layers in a three-dimensional data space. Such a system permits the rapid incorporation of data sets, rapid comparison of data sets, and adaptation to variable scales by resampling the raster scans.

  19. Importance of budgets for estimating the input of groundwater-derived nutrients to an eutrophic tidal river and estuary

    NASA Astrophysics Data System (ADS)

    Makings, Uriah; Santos, Isaac R.; Maher, Damien T.; Golsby-Smith, Lindsay; Eyre, Bradley D.

    2014-04-01

    Groundwater is often overlooked as a source of nutrients to estuaries and most previous groundwater-surface water exchange studies did not consider the input of dissolved organic nutrients. Here, we hypothesize that groundwater is contributing to high dissolved inorganic and organic nutrient concentrations in an eutrophic subtropical tidal river and estuary (Caboolture River, Queensland, Australia). Several spatial radon (222Rn, a natural groundwater tracer) surveys indicated that the majority of groundwater discharge occurred in the tidal river just upstream of the estuary, and that the radon hotspot did not necessarily coincide with the nutrient hotspot. A radon mass balance revealed that groundwater discharge into the tidal river was equivalent to about 50% of the gauged river flow in February 2012. Groundwater discharge apparently contributed 85% of ammonium and 35% of phosphate entering the estuary. In spite of significant correlations between radon and nitrate and dissolved organic nitrogen (DON) during spatial surveys, groundwater could account for only 7% of nitrate and 9% of DON inputs due to low groundwater concentrations and other sources (i.e., apparently a sewage treatment plant for nitrate and floodplain tributaries for DON). Because total dissolved nitrogen (TDN) was dominated by DON (69%) and nitrate (23%), the groundwater ammonium inputs were a minor source to the TDN pool within the tidal river and estuary. This study demonstrated that correlations between a groundwater tracer and nutrient concentrations do not necessarily illustrate causation. To assess how groundwater drives nutrient dynamics in estuaries, it may be important to include the tidal river (not only the estuarine salinity gradient) in field investigations, consider DON (not only ammonium and nitrate), and perform detailed budgets that include minor tributaries.

  20. Learning photographic global tonal adjustment with a database of input\\/output image pairs

    Microsoft Academic Search

    Vladimir Bychkovsky; Sylvain Paris; Eric Chan; Fredo Durand

    2011-01-01

    Adjusting photographs to obtain compelling renditions requires skill and time. Even contrast and brightness adjustments are challenging because they require taking into account the image content. Photographers are also known for having different retouching preferences. As the result of this complexity, rule-based, one-size-fits-all automatic techniques often fail. This problem can greatly benefit from supervised machine learning but the lack of

  1. Learning photographic global tonal adjustment with a database of input \\/ output image pairs

    Microsoft Academic Search

    Vladimir Bychkovsky; Sylvain Paris; Eric Chan; Fredo Durand

    2011-01-01

    Adjusting photographs to obtain compelling renditions requires skill and time. Even contrast and brightness adjustments are challenging because they require taking into account the image content. Photographers are also known for having different retouching preferences. As the result of this complexity, rule-based, one-size-fits-all automatic techniques often fail. This problem can greatly benefit from supervised machine learning but the lack of

  2. Estimates of the inputs of polychlorinated biphenyls and organochlorine insecticides to the River Thames derived from the sediment record

    NASA Astrophysics Data System (ADS)

    Scrimshaw, M. D.; Lester, J. N.

    Sediment deposited in the Tilbury Basin exhibited two distinct zones where contamination with organochlorine insecticides (OCL) and polychlorinated biphenyls (PCB) differed by up to an order of magnitude. The upper section of the core had an average concentration of 39 ng g-1 PCB and SigmaDDT (sum of concentrations of DDT, DDD and DDE) 47 ng g-1 whereas in the lower section these were 309 and 87 ng g-1 respectively. This difference was attributed to improvements in waste water treatment technology, specifically the extension of activated sludge treatment at Beckton and its introduction at Crossness sewage treatment works (STW) between 1959 and 1964. At the time Beckton alone was the largest STW in Europe, treating waste from a population of 2.82 million in 1961, with a flow of 1.14 x 106 m3 d-1 through the works making it the largest tributary of the Thames. The abruptness of change in pollutant concentrations observed in cored sediments at -5.82 m below Ordnance Datum Newlyn (OD) was linked to dredging activities within the basin and did not reflect rates of temporal changes in inputs. There was evidence to suggest that dechlorination of PCB had occurred within the deposited sediments. This was expressed as a change in the ratios of lower chlorinated (tri- and tetra-) congeners relative to those with 5 or more substituted chlorine atoms. An average ratio of 0.23 from the sediment surface to -2.29 m OD changed to 0.32 and subsequently increased to 0.62 between -5.82 m to -9.55 m OD. A number of factors may account for changes in microbial dechlorination activity. However, the possibility that changes in input sources were responsible for such effects cannot be discounted.

  3. Derivation of an indoor air averaging time model from the mass balance equation for the case of independent source inputs and fixed air exchange rates

    SciTech Connect

    Switzer, P.; Ott, W.

    1993-01-01

    Previous human activity pattern-exposure models have required improved ways for handling the serial autocorrelation of pollutant concentrations in indoor and in-transit microenvironments. Because existing models often sample concentrations from microenvironmental distributions for different averaging times, one approach for handling this autocorrelation is to develop an averaging time model for each microenvironment of importance. The paper explores a new approach for developing averaging time models: deriving the model theoretically from the mass balance equation, which describes the relationship between the time series of the input and output concentrations of any pollutant introduced into a well-mixed chamber. Beginning with the mass balance equation, the paper derives an averaging time model that predicts the mean, variance, and autocorrelation of the time series of pollutant concentrations in a well-mixed chamber for any averaging time. The paper considers the case of a discrete model in which the input source concentration is a time series of independent, piecewise-constant concentrations of equal duration while the air exchange rate remains fixed. Because the model is derived theoretically, the model is exact for the conditions specified. The goal of the research is to provide human exposure researchers with basic concepts for designing and developing useful, practical algorithms for future exposure and indoor air quality models.

  4. Classification and Visualization Based on Derived Image Features: Application to Genetic Syndromes

    PubMed Central

    Balliu, Brunilda; Würtz, Rolf P.; Horsthemke, Bernhard; Wieczorek, Dagmar; Böhringer, Stefan

    2014-01-01

    Data transformations prior to analysis may be beneficial in classification tasks. In this article we investigate a set of such transformations on 2D graph-data derived from facial images and their effect on classification accuracy in a high-dimensional setting. These transformations are low-variance in the sense that each involves only a fixed small number of input features. We show that classification accuracy can be improved when penalized regression techniques are employed, as compared to a principal component analysis (PCA) pre-processing step. In our data example classification accuracy improves from 47% to 62% when switching from PCA to penalized regression. A second goal is to visualize the resulting classifiers. We develop importance plots highlighting the influence of coordinates in the original 2D space. Features used for classification are mapped to coordinates in the original images and combined into an importance measure for each pixel. These plots assist in assessing plausibility of classifiers, interpretation of classifiers, and determination of the relative importance of different features. PMID:25405460

  5. Late quaternary Mediterranean sapropels. III. Assessment of source of input and palaeotemperature as derived from biological markers

    SciTech Connect

    Ten Haven, H.L.; Baas, M.; Kroot, M.; De Leeuw, J.W.; Schenck, P.A.; Ebbing, J.

    1987-04-01

    Sources of input contributing to the organic matter of four different Mediterranean sapropels (S/sub 1/, S/sub 5/, S/sub 6/, S/sub 7/) are inferred from the relative distributions of terrigenous and marine biological markers in these Quaternary deposits. The relative terrigenous contribution does not vary significantly. Within the marine contribution there is a significant compositional variation. A contribution from dinoflagellates is relatively important in the S/sub 1/ sapropel, whereas sapropels S/sub 6/ and S/sub 7/ are characterized by a relatively large contribution from prymnesiophyte algae and planktonic cyanobacteria. The abundance of diatoms in sapropel S/sub 5/, as deduced from microscopic observations, is probably reflected by a high concentration of loliolide. Variations in sea-surface water temperatures can be deduced from the relative abundance of di- and triunsaturated C/sub 37/ ketones and from the relative abundance of esterified 27-nor-24-methylcholesta-5,22E-dien-3..beta..-ol and cholesta-5,22E-dien-3..beta..-ol. These two molecular temperature indices are consistent with the delta /sup 18/O record and with the pollen record of the sapropels investigated.

  6. Input-output analysis of in vivo photoassimilate translocation using Positron-Emitting Tracer Imaging System (PETIS) data.

    PubMed

    Keutgen, Anna J; Keutgen, Norbert; Matsuhashi, Shinpei; Mizuniwa, Chizuko; Ito, Takehito; Fujimura, Takashi; Ishioka, Noriko-Shigeta; Watanabe, Satoshi; Osa, Akihiko; Sekine, Toshiaki; Uchida, Hiroshi; Tsuji, Atsunori; Hashimoto, Shoji

    2005-05-01

    The Positron-Emitting Tracer Imaging System (PETIS) is introduced for monitoring the distribution of (11)C-labelled photoassimilates in Sorghum. The obtained two-dimensional image data were quantitatively analysed using a transfer function analysis approach. While one half of a Sorghum root in a split root system was treated with either 0, 100, or 500 mM NaCl dissolved in the nutrient solution, tracer images of the root halves and the lower stem section were recorded using PETIS. From the observed tracer levels, parameters were estimated, from which the mean speed of tracer transport and the proportion of tracer moved between specified image positions were deduced. Transport speed varied between 0.7 and 1.8 cm min(-1) with the difference depending on which part of the stem was involved. When data were collected in the lowest 0.5-1 cm of the stem, which included the point where the roots emerge, transport speed was less. Rapid changes in NaCl concentration, from 0 to 100 mM, resulted in short-term increases of assimilate import into the treated root. This response represented a transient osmotic effect, that was compensated for in the medium-term by osmotic adaptation. Higher concentrations of NaCl (500 mM) resulted in distinctly less photoassimilate transport into the treated root half. The present results agree with earlier observations, showing that transport of (11)C-labelled photoassimilates measured with the PETIS detector system can be quantified using the method of input-output analysis. It is worth noting that with the PETIS detector system, areas of interest do not need to be defined until after data collection. This means that unexpected behaviour of a plant organ will be seen, which is not necessarily the case with conventional detector systems looking at predefined areas of interest. PMID:15809281

  7. The structure of protostellar envelopes derived from submillimeter continuum images

    E-print Network

    Claire J. Chandler; John S. Richer

    1999-09-29

    High dynamic range imaging of submillimeter dust emission from the envelopes of eight young protostars in the Taurus and Perseus star-forming regions has been carried out using the SCUBA submillimeter camera on the James Clerk Maxwell Telescope. Good correspondence between the spectral classifications of the protostars and the spatial distributions of their dust emission is observed, in the sense that those with cooler spectral energy distributions also have a larger fraction of the submillimeter flux originating in an extended envelope compared with a disk. This results from the cool sources having more massive envelopes rather than warm sources having larger disks. Azimuthally-averaged radial profiles of the dust emission are used to derive the power-law index of the envelope density distributions, p (defined by rho proportional to r^-p), and most of the sources are found to have values of p consistent with those predicted by models of cloud collapse. However, the youngest protostars in our sample, L1527 and HH211-mm, deviate significantly from the theoretical predictions, exhibiting values of p somewhat lower than can be accounted for by existing models. For L1527 heating of the envelope by shocks where the outflow impinges on the surrounding medium may explain our result. For HH211-mm another explanation is needed, and one possibility is that a shallow density profile is being maintained in the outer envelope by magnetic fields and/or turbulence. If this is the case star formation must be determined by the rate at which the support is lost from the cloud, rather than the hydrodynamical properties of the envelope, such as the sound speed.

  8. Derivation of Population Distribution Using Remote Sensing and Statistical Data as an Input for Tsunami Risk Assessment

    NASA Astrophysics Data System (ADS)

    Khomarudin, R.; Strunz, G.; Post, J.; Zosseder, K.; Ludwig, R.

    2009-04-01

    Information about people distribution is a crucial component in disaster risk management. Every disaster such as flood, drought, tsunami, volcanic eruption, storm, earthquake etc. implies threats to people with respect to loss of live, injury, and suffer. The number of people affected during 1991 - 2005 is approximately 3.5 billion people (UN ESCAP note), and that means more than 50% of people on the world are affected by disasters. Therefore, the information on people distribution in the disaster or hazard zone is important in order to mitigate the impact of natural disasters. Especially for tsunami, this information will help the government to better manage the evacuation of people and to estimate the number of people affected if there is tsunami event in their area. Normally, the available information on population distribution is based statistical data related to administrative boundaries, e.g. village, municipal, district, province, or national level. This research focuses on the improvement of the spatial resolution of data on the people distribution covering the area along the west coast Sumatera, South Coast of Java, and Bali. The results are used as an input for tsunami risk assessment in the framework of the GITEWS project. A combination of the number of people at village level with land use maps is under¬taken in this research. GIS and remote sensing techniques are used to improve the spatial detail of statistical data on people distribution. The model is based on an analysis of people activities in a certain land use. To assign appropriate weighting factors, census data and potential of village (PODES) data are used. The results of this research are detailed people distribution maps (day and night time) for the Coast of Sumatera, South Coast of Java, and Coastal of Bali. The spatial improvement can be shown. Moreover, besides the spatial improvement, the results also provide information on the distribution during day and night time. To estimate the accuracy of this approach, sensitivity analyses have been performed, which show the quality of the results. Keywords: spatial improvement, people distribution, census, land use, risk assessment

  9. The least-squares mixing models to generate fraction images derived from remote sensing multispectral data

    NASA Technical Reports Server (NTRS)

    Shimabukuro, Yosio Edemir; Smith, James A.

    1991-01-01

    Constrained-least-squares and weighted-least-squares mixing models for generating fraction images derived from remote sensing multispectral data are presented. An experiment considering three components within the pixels-eucalyptus, soil (understory), and shade-was performed. The generated fraction images for shade (shade image) derived from these two methods were compared by considering the performance and computer time. The derived shade images are related to the observed variation in forest structure, i.e., the fraction of inferred shade in the pixel is related to different eucalyptus ages.

  10. Linear alkylbenzenes as tracers of sewage-sludge-derived inputs of organic matter, PCBs, and PAHs to sediments at the 106-mile deep water disposal site

    USGS Publications Warehouse

    Lamoureux, E.M.; Brownawell, B.J.; Bothner, Michael H.

    1996-01-01

    Linear alkylbenzenes (LABs) are sensitive source-specific tracers of sewage inputs to the marine environment. Because they are highly particle reactive and nonspecifically sorbed to organic matter, LABs are potential tracers of the transport of both sludge-derived organic matter and other low solubility hydrophobic contaminants (e.g., PCBs and PAHs); sediment trap studies at the 106-Mile Site have shown LABs to be valuable in testing models of sludge deposition to the sea floor. In this study we report on the distributions of LABs, PCBs, PAHs, and Ag in surface sediments collected within a month of the complete cessation of dumping (July, 1992) in the vicinity of the dump site. Total LAB concentrations were lower than those measured by Takada and coworkers in samples from nearby sites collected in 1989. LABs from both studies appear to be significantly depleted (6 to 25-fold) in surface sediments relative to excess Ag (another sludge tracer) when compared to sewage sludge and sediment trap compositions. Comparison of LAB sediment inventories to model predictions of sludge particle fluxes supports the contention that LABs have been lost from the bed. The use of LABs to examine the short-or long-term fate of sludge derived materials in deep-sea sediments should be questioned. The causes of this LAB depletion are unclear at this point, and we discuss several hypotheses. The concentrations of total PCBs and PAHs are both correlated with sludge tracers, suggesting that there may be a measurable contribution of sludge-derived inputs on top of other nonpoint sources of these contaminant classes. This possibility is consistent with the composition of these contaminants determined in recent and historical analyses of sewage sludge.

  11. Optimization of a Model Corrected Blood Input Function from Dynamic FDG-PET Images of Small Animal Heart In Vivo

    PubMed Central

    Zhong, Min; Kundu, Bijoy K.

    2013-01-01

    Quantitative evaluation of dynamic Positron Emission Tomography (PET) of mouse heart in vivo is challenging due to the small size of the heart and limited intrinsic spatial resolution of the PET scanner. Here, we optimized a compartment model which can simultaneously correct for spill over and partial volume effects for both blood pool and the myocardium, compute kinetic rate parameters and generate model corrected blood input function (MCBIF) from ordered subset expectation maximization – maximum a posteriori (OSEM-MAP) cardiac and respiratory gated 18F-FDG PET images of mouse heart with attenuation correction in vivo, without any invasive blood sampling. Arterial blood samples were collected from a single mouse to indicate the feasibility of the proposed method. In order to establish statistical significance, venous blood samples from n=6 mice were obtained at 2 late time points, when SP contamination from the tissue to the blood is maximum. We observed that correct bounds and initial guesses for the PV and SP coefficients accurately model the wash-in and wash-out dynamics of the tracer from mouse blood. The residual plot indicated an average difference of about 1.7% between the blood samples and MCBIF. The downstream rate of myocardial FDG influx constant, Ki (0.15±0.03 min?1), compared well with Ki obtained from arterial blood samples (P=0.716). In conclusion, the proposed methodology is not only quantitative but also reproducible. PMID:24741130

  12. "Sonoelasticity" images derived from ultrasound signals in mechanically vibrated tissues.

    PubMed

    Lerner, R M; Huang, S R; Parker, K J

    1990-01-01

    A method has been developed for detecting and imaging the relative "stiffness," or elasticity of tissues. Externally applied vibration at low frequencies (10-1000 Hz) is used to induce oscillations within soft tissues, and the motion is detected by Doppler ultrasound. The results are displayed in a format resembling conventional Doppler color flow mapping, and are termed "sonoelasticity images." Preliminary experiments indicate that these novel images may be useful for detecting hard tumors in the prostate, liver, breast, and other organs. PMID:1694603

  13. Using Sediment Records to Reconstruct Historical Inputs Combustion-Derived Contaminants to Urban Airsheds/Watersheds: A Case Study From the Puget Sound

    NASA Astrophysics Data System (ADS)

    Louchouarn, P. P.; Kuo, L.; Brandenberger, J.; Marcantonio, F.; Wade, T. L.; Crecelius, E.; Gobeil, C.

    2008-12-01

    Urban centers are major sources of combustion-derived particulate matter (e.g. black carbon (BC), polycyclic aromatic hydrocarbons (PAH), anhydrosugars) and volatile organic compounds to the atmosphere. Evidence is mounting that atmospheric emissions from combustion sources remain major contributors to air pollution of urban systems. For example, recent historical reconstructions of depositional fluxes for pyrogenic PAHs close to urban systems have shown an unanticipated reversal in the trends of decreasing emissions initiated during the mid-20th Century. Here we compare a series of historical reconstructions of combustion emission in urban and rural airsheds over the last century using sedimentary records. A complex suite of combustion proxies (BC, PAHs, anhydrosugars, stable lead concentrations and isotope signatures) assisted in elucidating major changes in the type of atmospheric aerosols originating from specific processes (i.e. biomass burning vs. fossil fuel combustion) or fuel sources (wood vs. coal vs. oil). In all studied locations, coal continues to be a major source of combustion-derived aerosols since the early 20th Century. Recently, however, oil and biomass combustion have become substantial additional sources of atmospheric contamination. In the Puget Sound basin, along the Pacific Northwest region of the U.S., rural locations not impacted by direct point sources of contamination have helped assess the influence of catalytic converters on concentrations of oil-derived PAH and lead inputs since the early 1970s. Although atmospheric deposition of lead has continued to drop since the introduction of catalytic converters and ban on leaded gasoline, PAH inputs have "rebounded" in the last decade. A similar steady and recent rise in PAH accumulations in urban systems has been ascribed to continued urban sprawl and increasing vehicular traffic. In the U.S., automotive emissions, whether from gasoline or diesel combustion, are becoming a major source of combustion-derived PM and BC to the atmosphere and have started to replace coal as the major source in some surficial reservoirs. This increased urban influence of gasoline and diesel combustion on BC emissions was also observed in Europe both from model estimates as well as from measured fluxes in recent lake sediments.

  14. Techniques to derive geometries for image-based Eulerian computations

    PubMed Central

    Dillard, Seth; Buchholz, James; Vigmostad, Sarah; Kim, Hyunggun; Udaykumar, H.S.

    2014-01-01

    Purpose The performance of three frequently used level set-based segmentation methods is examined for the purpose of defining features and boundary conditions for image-based Eulerian fluid and solid mechanics models. The focus of the evaluation is to identify an approach that produces the best geometric representation from a computational fluid/solid modeling point of view. In particular, extraction of geometries from a wide variety of imaging modalities and noise intensities, to supply to an immersed boundary approach, is targeted. Design/methodology/approach Two- and three-dimensional images, acquired from optical, X-ray CT, and ultrasound imaging modalities, are segmented with active contours, k-means, and adaptive clustering methods. Segmentation contours are converted to level sets and smoothed as necessary for use in fluid/solid simulations. Results produced by the three approaches are compared visually and with contrast ratio, signal-to-noise ratio, and contrast-to-noise ratio measures. Findings While the active contours method possesses built-in smoothing and regularization and produces continuous contours, the clustering methods (k-means and adaptive clustering) produce discrete (pixelated) contours that require smoothing using speckle-reducing anisotropic diffusion (SRAD). Thus, for images with high contrast and low to moderate noise, active contours are generally preferable. However, adaptive clustering is found to be far superior to the other two methods for images possessing high levels of noise and global intensity variations, due to its more sophisticated use of local pixel/voxel intensity statistics. Originality/value It is often difficult to know a priori which segmentation will perform best for a given image type, particularly when geometric modeling is the ultimate goal. This work offers insight to the algorithm selection process, as well as outlining a practical framework for generating useful geometric surfaces in an Eulerian setting. PMID:25750470

  15. Localization, Stability, and Resolution of Topological Derivative Based Imaging Functionals in Elasticity

    E-print Network

    Ammari, Habib; Garnier, Josselin; Jing, Wenjia; Kang, Hyeonbae; Wahab, Abdul

    2012-01-01

    The focus of this work is on rigorous mathematical analysis of the topological derivative based detection algorithms for the localization of an elastic inclusion of vanishing characteristic size. A filtered quadratic misfit is considered and the performance of the topological derivative imaging functional resulting therefrom is analyzed. Our analysis reveals that the imaging functional may not attain its maximum at the location of the inclusion. Moreover, the resolution of the image is below the diffraction limit. Both phenomena are due to the coupling of pressure and shear waves propagating with different wave speeds and polarization directions. A novel imaging functional based on the weighted Helmholtz decomposition of the topological derivative is, therefore, introduced. It is thereby substantiated that the maximum of the imaging functional is attained at the location of the inclusion and the resolution is enhanced and it proves to be the diffraction limit. Finally, we investigate the stability of the prop...

  16. Three-dimensional reconstruction of microscopic images using different order intensity derivatives

    NASA Astrophysics Data System (ADS)

    Wang, Yu; Jiang, Huan

    2015-02-01

    Fluorescence microscopic image three-dimensional (3-D) reconstruction is a challenging topic in image processing and computer vision, and can be widely applied to life science, biology, and medicine. A microscopic images 3-D reconstruction method is proposed for transparent or partially transparent microscopic samples, which is based on the Taylor expansion theorem and polynomial fitting. First, the image stack of the specimen is divided into several groups in an overlapping or nonoverlapping way along the optical axis, and the first image of every group is regarded as the reference image. Then, different order intensity derivatives are calculated using all the images of every group and a polynomial fitting method. Subsequently, a new image can be generated by means of Taylor expansion theorem and the calculated different order intensity derivatives and for which the distance to the reference image is ?z along the optical axis. Finally, the microscopic specimen can be reconstructed in 3-D form using deconvolution technology and all the images including both the observed and the generated images. The experimental results show the superior performance via processing simulated and real fluorescence microscopic degraded images.

  17. Localization, Stability, and Resolution of Topological Derivative Based Imaging Functionals in Elasticity

    E-print Network

    Garnier, Josselin

    30, 74B05; Secondary 47A52, 65J20 Key words. Elasticity imaging, elastic waves, topologicalLocalization, Stability, and Resolution of Topological Derivative Based Imaging Functionals in Elasticity Habib Ammari Elie Bretin Josselin Garnier § Wenjia Jing Hyeonbae Kang ¶ Abdul Wahab October 17

  18. High resolution VESTA LAMO atlas derived from Dawn FC images.

    NASA Astrophysics Data System (ADS)

    Roatsch, Thomas; Kersten, Elke; Matz, Klaus-Dieter; Preusker, Frank; Scholten, Frank; Jaumann, Ralf; Raymond, Carol A.; Russell, Cris T.

    2013-04-01

    Introduction: NASA's Dawn spacecraft entered orbit of the inner main belt asteroid 4 Vesta on July 16, 2011, and spent about one year in orbit to characterize the geology, elemental and mineralogical composition, topography, shape, and internal structure of Vesta before it departed to asteroid 1 Ceres in late 2012. One of the major goals of the mission was a global mapping of Vesta. Data: The DAWN mission was mapping Vesta from three different orbit heights during Survey orbit (3100 km altitude), HAMO (High Altitude Mapping Orbit, 700 km altitude), and LAMO (Low Altitude Mapping Orbit, 210 km altitude) [1]. The Dawn mission is equipped with a framing camera (FC) [2] which was the prime instrument during the LAMO phase. DAWN orbited Vesta during LAMO in 21 cycles between December 2011 and end of April 2012. The framing camera took about 10,000 clear filter images with a resolution of about 20 m/pixel during these cycles. The images were taken with different viewing angles and different illumination conditions. We selected about 8,000 images for the global coverage of Vesta. Data Processing: The first step of the processing chain is to ortho rectify the images to the proper scale and map projection type. This process requires detailed high-resolution information of the local topography of Vesta. The global topgraphy was calculated during the stereo processing of the HAMO images [3] and was used here. The shape model was used for the calculation of the ray intersection points while the map projection itself was done onto a sphere with a mean radius of 255 km. The next step was the mosaicking of all images to one global mosaic of Vesta, the so called basemap. Vesta map tiles: The Vesta atlas was produced in a scale of 1:200,000 and consists of 30 tiles that conform to the quadrangle scheme proposed by Greeley and Batson [4] and is used for example for mapping Mars in a scale of 1:5,000,000. A map scale of 1:200,000 guarantees a mapping at the highest available DAWN resolution in LAMO and results in an acceptable printing scale for the hardcopy map of 10 pixel/mm. The individual tiles were separately mosaicked and reprojected. Nomenclature: The DAWN team proposed to the International Astronomical Union (IAU) to use the names of vestal virgins and famous Roman women as names for the craters and to use names of places and festivals associated with vestal virgins for other feature names. This proposal was accepted by the IAU and the team could propose 50 names for geological features to the IAU which were also approved [5]. These feature names were applied to the map tiles. The entire Vesta atlas consisting of 30 map tiles will become available to the public through the Planetary Photojournal and the PDS. References: [1] Russell, C.T. and Raymond, C.A., Space Sci. Review, 163, DOI 10.1007/s11214-011-9836-2; [2] Sierks, et al., 2011, Space Sci. Rev., 163, DOI 10.1007/s11214-011-9745-4; [3] Preusker, F. et al., this session; [4] Greeley, R. and Batson, G., 1990, Planetary Mapping, Cambridge University Press; [5] http://planetarynames.wr.usgs.gov/Page/VESTA/target

  19. MLT Dependent Plasmapause Location Derived from IMAGE EUV

    NASA Astrophysics Data System (ADS)

    Katus, Roxanne M.; Gallagher, Dennis; Liemohn, Michael; Keesee, Amy M.

    2015-04-01

    The location of the outer edge of the plasmasphere (the plasmapause) as a function of geomagnetic storm-time is identified and investigated statistically in relation to the solar wind driver. Imager for Magnetopause-to-Aurora Global Exploration (IMAGE) Extreme Ultraviolet (EUV) data are used to create an automated method that locates and extracts the plasmapause. The plasmapause extraction technique searches a set range of possible plasmasphere densities for a maximum gradient. The magnetic local time (MLT) dependent plasmapause results are compared to manual extraction results. The plasmapause results from 39 intense storms are examined along a normalized epoch storm timeline to determine the average plasmapause L-shell as a function of MLT and storm-time. The average extracted plasmapause L-shell follows the expected storm-time plasmapause behavior. The results show that, during the main phase, the plasmapause moves Earthward and a plasmaspheric drainage plume forms near dusk and across the dayside during strong convection. During the recovery phase the plume becomes re-entrained in corotational motion around the Earth, while the average plasmapause location moves further from the Earth. The results are also investigated in terms of the solar wind driver. We find evidence that shows that the inner magnetospheric response to Magnetic Cloud (MC) and Sheath (SH)-driven events is similar but the response is different for CIR-driven events.

  20. No-reference image quality assessment based on log-derivative statistics of natural scenes

    NASA Astrophysics Data System (ADS)

    Zhang, Yi; Chandler, Damon M.

    2013-10-01

    We propose an efficient blind/no-reference image quality assessment algorithm using a log-derivative statistical model of natural scenes. Our method, called DErivative Statistics-based QUality Evaluator (DESIQUE), extracts image quality-related statistical features at two image scales in both the spatial and frequency domains. In the spatial domain, normalized pixel values of an image are modeled in two ways: pointwise-based statistics for single pixel values and pairwise-based log-derivative statistics for the relationship of pixel pairs. In the frequency domain, log-Gabor filters are used to extract the fine scales of the image, which are also modeled by the log-derivative statistics. All of these statistics can be fitted by a generalized Gaussian distribution model, and the estimated parameters are fed into combined frameworks to estimate image quality. We train our models on the LIVE database by using optimized support vector machine learning. Experiment results tested on other databases show that the proposed algorithm not only yields a substantial improvement in predictive performance as compared to other state-of-the-art no-reference image quality assessment methods, but also maintains a high computational efficiency.

  1. Martian spectral units derived from ISM imaging spectrometer data

    NASA Technical Reports Server (NTRS)

    Murchie, S.; Mustard, J.; Saylor, R.

    1993-01-01

    Based on results of the Viking mission, the soil layer of Mars has been thought to be fairly homogeneous and to consist of a mixture of as few as two components, a 'dark gray' basaltic material and a 'bright red' altered material. However, near-infrared reflectance spectra measured recently both telescopically and from spacecraft indicate compositional heterogeneity beyond what can be explained by just two components. In particular, data from the ISM imaging spectrometer, which observed much of the equatorial region at a spatial resolution of approximately 22 km, indicate spatial differences in the presence and abundance of Fe-containing phases, hydroxylated silicates, and H2O. The ISM data was used to define, characterize, and map soil 'units' based on their spectral properties. The spatial distribution of these 'units' were compared to morphologic, visible color, and thermal inertia features recognized in Viking data.

  2. Shear-wave velocity profile and seismic input derived from ambient vibration array measurements: the case study of downtown L'Aquila

    NASA Astrophysics Data System (ADS)

    Di Giulio, Giuseppe; Gaudiosi, Iolanda; Cara, Fabrizio; Milana, Giuliano; Tallini, Marco

    2014-08-01

    Downtown L'Aquila suffered severe damage (VIII-IX EMS98 intensity) during the 2009 April 6 Mw 6.3 earthquake. The city is settled on a top flat hill, with a shear-wave velocity profile characterized by a reversal of velocity at a depth of the order of 50-100 m, corresponding to the contact between calcareous breccia and lacustrine deposits. In the southern sector of downtown, a thin unit of superficial red soils causes a further shallow impedance contrast that may have influenced the damage distribution during the 2009 earthquake. In this paper, the main features of ambient seismic vibrations have been studied in the entire city centre by using array measurements. We deployed six 2-D arrays of seismic stations and 1-D array of vertical geophones. The 2-D arrays recorded ambient noise, whereas the 1-D array recorded signals produced by active sources. Surface-wave dispersion curves have been measured by array methods and have been inverted through a neighbourhood algorithm, jointly with the H/V ambient noise spectral ratios related to Rayleigh waves ellipticity. We obtained shear-wave velocity (Vs) profiles representative of the southern and northern sectors of downtown L'Aquila. The theoretical 1-D transfer functions for the estimated Vs profiles have been compared to the available empirical transfer functions computed from aftershock data analysis, revealing a general good agreement. Then, the Vs profiles have been used as input for a deconvolution analysis aimed at deriving the ground motion at bedrock level. The deconvolution has been performed by means of EERA and STRATA codes, two tools commonly employed in the geotechnical engineering community to perform equivalent-linear site response studies. The waveform at the bedrock level has been obtained deconvolving the 2009 main shock recorded at a strong motion station installed in downtown. Finally, this deconvolved waveform has been used as seismic input for evaluating synthetic time-histories in a strong-motion target site located in the middle Aterno river valley. As a target site, we selected the strong-motion station of AQV 5 km away from downtown L'Aquila. For this site, the record of the 2009 L'Aquila main shock is available and its surface stratigraphy is adequately known making possible to propagate the deconvolved bedrock motion back to the surface, and to compare recorded and synthetic waveforms.

  3. The platelet-derived growth factor beta receptor triggers multiple cytoplasmic signaling cascades that arrive at the nucleus as distinguishable inputs.

    PubMed

    Montmayeur, J P; Valius, M; Vandenheede, J; Kazlauskas, A

    1997-12-19

    Stimulation of the platelet-derived growth factor beta receptor (betaPDGFR) activates enzymes such as phosphatidylinositol 3-kinase (PI3K) and phospholipase Cgamma1 (PLCgamma), which ultimately initiate nuclear responses such as enhanced expression of immediate early genes. In an attempt to compare the signaling cascades initiated by PI3K and PLCgamma, we examined the activation of a panel of immediate early genes by betaPDGFR mutants, which preferentially engage PI3K or PLCgamma. When expressed in A431 cells, the wild type receptor and to a lesser extent the mutant receptor that associates with PLCgamma (Y1021) was able to up-regulate c-fos, junB, and KC mRNA expression. In contrast, the receptor mutant that engages PI3K (Y740/51) poorly stimulated c-fos mRNA expression and did not significantly stimulate expression of either JunB or KC. Receptor mutants that did not associate with either PI3K or PLCgamma were dramatically compromised or unable to increase expression of any of these immediate early genes. The differential ability of the Y1021 and Y740/51 receptors to activate c-fos correlated well with an apparent difference in their ability to engage distinct protein kinase C family members. However there did appear to be a degree of redundancy in the cytoplasmic signaling pathways initiated by PI3K and PLCgamma, since both the Y1021 and Y740/51 receptors were able to activate an AP-1-responsive element. We conclude that recruitment of signal relay enzymes to the betaPDGFR is necessary for PDGF-dependent activation of at least some immediate early genes. In addition, whereas the betaPDGFR activates multiple signaling enzymes capable of activating the same nuclear response (activation of c-fos), these signaling cascades do not appear to converge in the cytoplasm but arrive at the nucleus as distinguishable inputs. PMID:9405485

  4. MR image super-resolution reconstruction using sparse representation, nonlocal similarity and sparse derivative prior.

    PubMed

    Zhang, Di; He, Jiazhong; Zhao, Yun; Du, Minghui

    2015-03-01

    In magnetic resonance (MR) imaging, image spatial resolution is determined by various instrumental limitations and physical considerations. This paper presents a new algorithm for producing a high-resolution version of a low-resolution MR image. The proposed method consists of two consecutive steps: (1) reconstructs a high-resolution MR image from a given low-resolution observation via solving a joint sparse representation and nonlocal similarity L1-norm minimization problem; and (2) applies a sparse derivative prior based post-processing to suppress blurring effects. Extensive experiments on simulated brain MR images and two real clinical MR image datasets validate that the proposed method achieves much better results than many state-of-the-art algorithms in terms of both quantitative measures and visual perception. PMID:25638262

  5. A super-resolution particle image velocimetry interrogation approach by means of velocity second derivatives correlation

    NASA Astrophysics Data System (ADS)

    Scarano, F.

    2004-02-01

    The present study proposes a super-resolution approach for the analysis of particle image velocimetry (PIV) recordings. The method is based on image correlation with respect to the second spatial derivatives of the particle image displacement distribution. The direct measurement of the displacement second derivatives (spatial curvature) is obtained by maximizing the product of deformed particle image patterns. The paper describes the performance of the cross-correlation approach in terms of spatial resolution in analogy with linear filters (moving average) as directly applied to the displacement distribution over the interrogation window. The proposed method aims at reducing the evaluation error and introduces a correlation scheme, which directly measures the local second derivatives of the displacement distribution over the interrogation window. The window product is maximized separately for each spatial derivative term in order to reduce the large computational cost associated with image deformation resampling and image product. The method's performance is assessed first by evaluating the modulation transfer function using synthetic PIV images with a one-dimensional sinusoidal displacement, where results show a factor of three spatial resolution enhancement. The extension to the two-dimensional case is obtained by simulation of homogeneous random fluctuations. The measurement uncertainty is kept at the same level as that of the window deformation iterative and multi-grid method (WIDIM). The assessment of the method's performances in actual experimental conditions is made by analysing a wall jet flow, focusing the attention on the steep velocity profile across the free shear layer. The assessment compares the velocity and vorticity profiles obtained by varying the size of the interrogation window. The factor of three improvement of the spatial resolution is also confirmed for the experimental case. However, a slight increase of the measurement uncertainty is observed.

  6. Relationship between sperm whale (Physeter macrocephalus) click structure and size derived from videocamera images

    E-print Network

    Paris-Sud XI, Université de

    Relationship between sperm whale (Physeter macrocephalus) click structure and size derived from videocamera images of a depredating whale (sperm whale prey acquisition) Delphine Mathiasa and Aaron Thode February 2009 Sperm whales have learned to depredate black cod Anoplopoma fimbria from longline deployments

  7. SOLAR SUBSURFACE FLUID DYNAMICS DESCRIPTORS DERIVED FROM GLOBAL OSCILLATION NETWORK GROUP AND MICHELSON DOPPLER IMAGER DATA

    E-print Network

    Corbard, Thierry

    AND MICHELSON DOPPLER IMAGER DATA R. Komm National Solar Observatory,1 950 North Cherry Avenue, Tucson, AZ 85719SOLAR SUBSURFACE FLUID DYNAMICS DESCRIPTORS DERIVED FROM GLOBAL OSCILLATION NETWORK GROUP,2 I. Gonza´lez Herna´ndez, F. Hill, R. Howe, and C. Toner National Solar Observatory, 950 North

  8. Effect of Scaling Transfer between Evapotranspiration Maps Derived from LandSat 7 and MODIS Images

    E-print Network

    Borchers, Brian

    Effect of Scaling Transfer between Evapotranspiration Maps Derived from LandSat 7 and MODIS Images distribution of evapotranspiration. Since the spatial resolution of evapotranspiration predictions depends and second to investigate the effect of up- and down-scaling procedures between evapotranspiration maps

  9. Derivation of distributions of surface albedo over land areas in Japan from GMS-5\\/VISSR images

    Microsoft Academic Search

    Koji Horiuchi; Hiroyuki Sakai; Mitsuo Minomura

    Satellite remote-sensing data on the sea and land areas provide the information on both the surface albedo and aerosol optical thickness (AOT). In this study, the surface albedo distributions are derived from the satellite data on the monthly composite image with relatively clear atmosphere, and subsequently, the AOT at 550 nm is extracted for relatively turbid days. The temporal changes

  10. The benefits of using short interval satellite images to derive winds for tropical cyclones

    NASA Technical Reports Server (NTRS)

    Rodgers, E.; Gentry, R. C.; Shenk, W. E.; Oliver, V.

    1978-01-01

    During the 1975, 1976, and 1977, NOAA's National Environmental Satellite Service and NASA's Goddard Space Flight Center conducted a cooperative program to determine the optimum resolution and frequency of satellite images for deriving winds to study and forecast tropical cyclones. Rapid scan images were obtained at 7.5 minute interval from SMS-2 for hurricane Eloise and cyclone Caroline, and at 3 minute intervals from GOES-1 for tropical storms Belle, Holly, and Anita. Cloud motions were derived from these images using the Atmospheric and Oceanographic Information Processing System. Winds that were derived from the movement of upper and lower tropospheric level clouds using rapid scan data were compared with the 15 and 30 minute interval data. Greater than 10 (5) times as many clouds could be tracked to obtain winds using 3 and 7.5 minute rapid scan images as when using 15 or 30 minute interval images. A few bright areas within the central dense overcast which appeared to be moving with the winds at low levels were tracked.

  11. Integration of Color and Local Derivative Pattern Features for Content-Based Image Indexing and Retrieval

    NASA Astrophysics Data System (ADS)

    Vipparthi, Santosh Kumar; Nagar, Shyam Krishna

    2014-09-01

    This paper presents two new feature descriptors for content based image retrieval (CBIR) application. The proposed two descriptors are named as color local derivative patterns (CLDP) and inter color local derivative pattern (ICLDP). In order to reduce the computational complexity the uniform patterns are applied to both CLDP and ICLDP. Further, uniform CLDP (CLDPu2) and uniform ICLDP (ICLDPu2) are generated respectively. The proposed descriptors are able to exploit individual (R, G and B) spectral channel information and co-relating pair (RG, GB, BR, etc.) of spectral channel information. The retrieval performances of the proposed descriptors (CLDP and ICLDP) are tested by conducting two experiments on Corel-5000 and Corel-10000 benchmark databases. The results after investigation show a significant improvement in terms of precision, average retrieval precision (ARP), recall and average retrieval rate (ARR) as compared to local binary patterns (LBP), local derivative patterns (LDP) and other state-of-the-art techniques for image retrieval.

  12. A Topological derivative based image segmentation for sign language recognition system using isotropic filter

    E-print Network

    Krishnaveni, M

    2010-01-01

    The need of sign language is increasing radically especially to hearing impaired community. Only few research groups try to automatically recognize sign language from video, colored gloves and etc. Their approach requires a valid segmentation of the data that is used for training and of the data that is used to be recognized. Recognition of a sign language image sequence is challenging because of the variety of hand shapes and hand motions. Here, this paper proposes to apply a combination of image segmentation with restoration using topological derivatives for achieving high recognition accuracy. Image quality measures are conceded here to differentiate the methods both subjectively as well as objectively. Experiments show that the additional use of the restoration before segmenting the postures significantly improves the correct rate of hand detection, and that the discrete derivatives yields a high rate of discrimination between different static hand postures as well as between hand postures and the scene b...

  13. Three very high resolution optical images for land use mapping of a suburban catchment: input to distributed hydrological models

    NASA Astrophysics Data System (ADS)

    Jacqueminet, Christine; Kermadi, Saïda; Michel, Kristell; Jankowfsky, Sonja; Braud, Isabelle; Branger, Flora; Beal, David; Gagnage, Matthieu

    2010-05-01

    Keywords : land cover mapping, very high resolution, remote sensing processing techniques, object oriented approach, distributed hydrological model, peri-urban area Urbanization and other modifications of land use affect the hydrological cycle of suburban catchments. In order to quantify these impacts, the AVuPUR project (Assessing the Vulnerability of Peri-Urban Rivers) is currently developing a distributed hydrological model that includes anthropogenic features. The case study is the Yzeron catchment (150 km²), located close to Lyon city, France. This catchment experiences a growing of urbanization and a modification of traditional land use since the middle of the 20th century, resulting in an increase of flooding, water pollution and river banks erosion. This contribution discusses the potentials of automated data processing techniques on three different VHR images, in order to produce appropriate and detailed land cover data for the models. Of particular interest is the identification of impermeable surfaces (buildings, roads, and parking places) and permeable surfaces (forest areas, agricultural fields, gardens, trees…) within the catchment, because their infiltration capacity and their impact on runoff generation are different. Three aerial and spatial images were acquired: (1) BD Ortho IGN aerial images, 0.50 m resolution, visible bands, may 5th 2008; (2) QuickBird satellite image, 2.44 m resolution, visible and near-infrared bands, august 29th 2008; (3) Spot satellite image, 2.50 m resolution, visible and near-infrared bands, September 22nd 2008. From these images, we developed three image processing methods: (1) a pixel-based method associated to a segmentation using Matlab®, (2) a pixel-based method using ENVI®, (3) an object-based classification using Definiens®. We extracted six land cover types from the BD Ortho IGN (visible bands) and height classes from the satellite images (visible and near infrared bands). The three classified images are resampled in the same low resolution of 2.5 m and compared in order to evaluate the accuracy of different image processing methods and to determine for each cover type, the more appropriate image and/or method. This comparison provides hydrologists with a synthetic land cover map. Four parameters affect the accuracy of land cover mapping: firstly the addition of the NIR band improves vegetation classification such as the distinction between coniferous forest and broad-leaved forest. Moreover the intensity of chlorophyllian activity allows us to characterize the use of agricultural fields. Secondly, the images were taken at three dates in the agricultural calendar. This multi-date data allows the discrimination between permanently vegetalized pastures, and temporarily bare crops, a useful information for hydrologists who study surfaces hydraulic properties. Thirdly, the high resolution of the BD Ortho IGN image emphasizes the heterogeneity inside the spatial entities. Thus, in urbanised areas, high-resolution imagery allows the precise identification of objects > 5 m2 and consequently the quantification of impervious and pervious surfaces. However, the continuity of forest areas is not maintained because of the presence of small entities with sparser tree cover that were classified as herbaceous areas. Finally, image characteristics are more crucial than classification methods for the accuracy of land cover mapping. However, object based approach improves the classification of mixed pixels on the edge between different objects. It's particularly true for buildings and roads.

  14. Image-derived biomarkers and multimodal imaging strategies for lung cancer management.

    PubMed

    Sauter, Alexander W; Schwenzer, Nina; Divine, Mathew R; Pichler, Bernd J; Pfannenberg, Christina

    2015-04-01

    Non-small-cell lung cancer is the most common type of lung cancer and one of the leading causes of cancer-related death worldwide. For this reason, advances in diagnosis and treatment are urgently needed. With the introduction of new, highly innovative hybrid imaging technologies such as PET/CT, staging and therapy response monitoring in lung cancer patients have substantially evolved. In this review, we discuss the role of FDG PET/CT in the management of lung cancer patients and the importance of new emerging imaging technologies and radiotracer developments on the path to personalized medicine. PMID:25573632

  15. Tri-stereo Pleiades images-derived digital surface models for tectonic geomorphology studies

    NASA Astrophysics Data System (ADS)

    Ferry, Matthieu; Le Roux-Mallouf, Romain; Ritz, Jean-François; Berthet, Théo; Peyret, Michel; Vernant, Philippe; Maréchal, Anaïs; Cattin, Rodolphe; Mazzotti, Stéphane; Poujol, Antoine

    2014-05-01

    Very high resolution digital elevation models are a key component of modern quantitative geomorphology. In parallel to high-precision but time-consuming kinematic GPS and/or total station surveys and dense coverage but expensive LiDAR campaigns, we explore the usability of affordable, flexible, wide coverage digital surface models (DSMs) derived from Pleiades tri-stereo optical images. We present two different approaches to extract DSM from a triplet of images. The first relies on the photogrammetric extraction of 3 DSMs from the 3 possible stereo couples and subsequent merge based on the best correlation score. The second takes advantage of simultaneous correlation over the 3 images to derive a point cloud. We further extract DSM from panchromatic 0.5 m resolution images and multispectral 2 m resolution images to test for correlation and noise and determine optimal correlation window size and achievable resolution. Georeferencing is also assessed by comparing raw coordinates derived from Pleiades Rational Polynomial Coefficients to ground control points. Primary images appear to be referenced within ~15 m over flat areas where parallax is minimal while derived DSMs and associated orthorectified images show a much improved referencing within ~5 m of GCPs. In order to assess the adequacy of Pleiades DSMs for tectonic geomorphology, we present examples from case studies along the Trougout normal fault (Morocco), the Hovd strike-slip fault (Mongolia), the Denali strike-slip fault (USA and Canada) and the Main Frontal Thrust (Bhutan). In addition to proposing a variety of tectonic contexts, these examples cover a wide range of climatic conditions (semi-arid, arctic and tropical), vegetation covers (bare earth, sparse Mediterranean, homogeneous arctic pine, varied tropical forest), lithological natures and related erosion rates. The capacity of derived DSMs is demonstrated to characterize geomorphic markers of active deformation such as marine and alluvial terraces, stream gullies, alluvial fans and fluvio-glacial deposits in terms of vertical (from DSMs) and horizontal (from orthorectified optical images) offsets. Values extracted from Pleiades DSMs compare well to field measurements in terms of relief and slope, which suggests effort and resources necessary for field topography could be significantly reduced, especially in poorly accessible areas.

  16. Assessment of brain glucose metabolism with input function determined from brain PET images by means of Bayesian ICA and MCMC methods.

    PubMed

    Berradja, Khadidja; Boughanmi, Nabil

    2012-12-01

    Positron emission tomography (PET) imaging has the capability to produce regional or parametric images of physiological aspects in a tissue of interest. Apart from the acquired PET data, the concentration of the radiotracer supplied to the tissue through the vascularization has to be known as the input function (IF). IF can be obtained by manual or automatic blood sampling and cross calibrated with PET. These procedures are cumbersome, invasive and generate uncertainties. In the present work, we determine IF from internal artery in fluorodeoxyglucose (18F-FDG) brain images by means of Independent Component Analysis (ICA) based on Bayesian theory and Monte Carlo Markov Chain (MCMC) sampling method (BICA, Bayesian ICA). Dynamic brain images were decomposed with BICA into image sequences of blood and tissue components. A region of interest was drawn around the internal artery in the blood image to determine BICA-IF. BICA-IF was therefore corrected for spillover of radioactivity emission from tissue, then it was normalized with three plasma samples to correct for partial volume and blood to plasma radioactivity ratio. BICA-IF was found comparable to IF determined by blood sampling, and rCMRG values in several brain structures obtained with BICA-IF and sampled IF showed a bias of 6.4% which was attributed to the difference in the time sampling of 4s for sampled IF versus 15 s for BICA-MC-IF at early times. In conclusion, BICA is a strong approach in image decomposition to extract blood curves in a noninvasive way. PMID:22884568

  17. A new method of phase derivative extracting for off-axis quantitative phase imaging

    NASA Astrophysics Data System (ADS)

    Xu, Yuanyuan; Wang, Yawei; Jin, Weifeng; Lv, Cuihong; Wu, Hui

    2013-09-01

    We present a new derivative method for phase information extraction in off-axis quantitative phase imaging (QPI). Similar to other rapid derivative method, this method only uses the interference term, the 1st and 2nd order derivatives of a single interferogram in QPI, but the assumption in our method is different from that of other derivative method. And this method can be used to optimize small spatial frequency processing capability in slightly off-axis QPI. We illustrate the proposed method with theory and simulation experiment of a ball, and prove our method by comparing our simulation results with the experimental results of the red blood cell and the skin cancer cell, respectively.

  18. Derivatives

    NSDL National Science Digital Library

    Bourne, Murray

    Murray Bourne developed the Interactive Mathematics site while working as a mathematics lecturer at Ngee Ann Polytechnic in Singapore. The site contains numerous mathematics tutorials and resources for students and teachers alike. This specific page is focused on differentiation, or finding derivatives. Bourne walks users through an introduction to differentiation and limits, and then moves on to more specific applications like rate of change, derivatives of polynomials, and differentiating powers of a function. Each topic includes graphs and interactive materials designed to aid users in understanding the presented concepts. The information here is presented in a clear, straightforward manner that is appropriate for introductory and advanced calculus students alike.

  19. In vivo imaging of human adipose-derived stem cells in Alzheimer's disease animal model.

    PubMed

    Ha, Sungji; Ahn, Sangzin; Kim, Saeromi; Joo, Yuyoung; Chong, Young Hae; Suh, Yoo-Hun; Chang, Keun-A

    2014-05-01

    Stem cell therapy is a promising tool for the treatment of diverse conditions, including neurodegenerative diseases such as Alzheimer's disease (AD). To understand transplanted stem cell biology, in vivo imaging is necessary. Nanomaterial has great potential for in vivo imaging and several noninvasive methods are used, such as magnetic resonance imaging, positron emission tomography, fluorescence imaging (FI) and near-infrared FI. However, each method has limitations for in vivo imaging. To overcome these limitations, multimodal nanoprobes have been developed. In the present study, we intravenously injected human adipose-derived stem cells (hASCs) that were labeled with a multimodal nanoparticle, LEO-LIVE™-Magnoxide 675 or 797 (BITERIALS, Seoul, Korea), into Tg2576 mice, an AD mouse model. After sequential in vivo tracking using Maestro Imaging System, we found fluorescence signals up to 10 days after injection. We also found strong signals in the brains extracted from hASC-transplanted Tg2576 mice up to 12 days after injection. With these results, we suggest that in vivo imaging with this multimodal nanoparticle may provide a useful tool for stem cell tracking and understanding stem cell biology in other neurodegenerative diseases. PMID:24297061

  20. In vivo imaging of human adipose-derived stem cells in Alzheimer's disease animal model

    NASA Astrophysics Data System (ADS)

    Ha, Sungji; Ahn, Sangzin; Kim, Saeromi; Joo, Yuyoung; Chong, Young Hae; Suh, Yoo-Hun; Chang, Keun-A.

    2014-05-01

    Stem cell therapy is a promising tool for the treatment of diverse conditions, including neurodegenerative diseases such as Alzheimer's disease (AD). To understand transplanted stem cell biology, in vivo imaging is necessary. Nanomaterial has great potential for in vivo imaging and several noninvasive methods are used, such as magnetic resonance imaging, positron emission tomography, fluorescence imaging (FI) and near-infrared FI. However, each method has limitations for in vivo imaging. To overcome these limitations, multimodal nanoprobes have been developed. In the present study, we intravenously injected human adipose-derived stem cells (hASCs) that were labeled with a multimodal nanoparticle, LEO-LIVE™-Magnoxide 675 or 797 (BITERIALS, Seoul, Korea), into Tg2576 mice, an AD mouse model. After sequential in vivo tracking using Maestro Imaging System, we found fluorescence signals up to 10 days after injection. We also found strong signals in the brains extracted from hASC-transplanted Tg2576 mice up to 12 days after injection. With these results, we suggest that in vivo imaging with this multimodal nanoparticle may provide a useful tool for stem cell tracking and understanding stem cell biology in other neurodegenerative diseases.

  1. Video image-based analysis of single human induced pluripotent stem cell derived cardiomyocyte beating dynamics using digital image correlation

    PubMed Central

    2014-01-01

    Background The functionality of a cardiomyocyte is primarily measured by analyzing the electrophysiological properties of the cell. The analysis of the beating behavior of single cardiomyocytes, especially ones derived from stem cells, is challenging but well warranted. In this study, a video-based method that is non-invasive and label-free is introduced and applied for the study of single human cardiomyocytes derived from induced pluripotent stem cells. Methods The beating of dissociated stem cell-derived cardiomyocytes was visualized with a microscope and the motion was video-recorded. Minimum quadratic difference, a digital image correlation method, was used for beating analysis with geometrical sectorial cell division and radial/tangential directions. The time series of the temporal displacement vector fields of a single cardiomyocyte was computed from video data. The vector field data was processed to obtain cell-specific, contraction-relaxation dynamics signals. Simulated cardiomyocyte beating was used as a reference and the current clamp of real cardiomyocytes was used to analyze the electrical functionality of the beating cardiomyocytes. Results Our results demonstrate that our sectorized image correlation method is capable of extracting single cell beating characteristics from the video data of induced pluripotent stem cell-derived cardiomyocytes that have no clear movement axis, and that the method can accurately identify beating phases and time parameters. Conclusion Our video analysis of the beating motion of single human cardiomyocytes provides a robust, non-invasive and label-free method to analyze the mechanobiological functionality of cardiomyocytes derived from induced pluripotent stem cells. Thus, our method has potential for the high-throughput analysis of cardiomyocyte functions. PMID:24708714

  2. MODIS-derived daily PAR simulation from cloud-free images and its validation

    Microsoft Academic Search

    Liangfu Chen; Yanhua Gao; Lei Yang; Qinhuo Liu; Xingfa Gu; Guoliang Tian

    2008-01-01

    In this paper, a MODIS-derived daily PAR (photosynthetically active radiation) simulation model from cloud-free image over land surface has been developed based on Bird and Riordan’s model. In this model, the total downwelling spectral surface irradiance is divided into two parts: one is beam irradiance, and another is diffuse irradiance. The attenuation of solar beam irradiance comprises scattering by the

  3. Optical imaging of progenitor cell homing to patient-derived tumors.

    PubMed

    Newton, Isabel G; Plaisted, Warren C; Messina-Graham, Steven; Abrahamsson Schairer, Annelie E; Shih, Alice Y; Snyder, Evan Y; Jamieson, Catriona H M; Mattrey, Robert F

    2012-01-01

    Capitalizing on cellular homing to cancer is a promising strategy for targeting malignant cells for diagnostic, monitoring and therapeutic purposes. Murine C17.2 neural progenitor cells (NPC) demonstrate a tropism for cell line-derived tumors, but their affinity for patient-derived tumors is unknown. We tested the hypothesis that NPC accumulate in patient-derived tumors at levels detectable by optical imaging. Mice bearing solid tumors after transplantation with patient-derived leukemia cells and untransplanted controls received 10(6) fluorescent DiR-labeled NPC daily for 1-4 days, were imaged, then sacrificed. Tissues were analyzed by immunofluorescence and flow cytometry to detect tumor cell engraftment (CD45) and NPC (FITC-? galactosidase or DiR). Tumors consisted primarily of CD45-positive cells and demonstrated mild fluorescence, corresponding to frequent clusters of FITC-? gal-positive cells. Both transplanted and control mice demonstrated the highest fluorescent signal in the spleens and other tissues of the reticuloendothelial activating system. However, only rare FITC-? gal-positive cells were detected in the mildly engrafted transplanted spleens and none in the control spleens, suggesting that their high DiR signal reflects the sequestration of DiR-positive debris. The mildly engrafted transplanted kidneys demonstrated low fluorescent signal and rare FITC-? gal-positive cells whereas control kidneys were negative. Results indicate that NPC accumulate in tissues containing patient-derived tumor cells in a manner that is detectable by ex vivo optical imaging and proportional to the level of tumor engraftment, suggesting a capacity to home to micrometastatic disease. As such, NPC could have significant clinical applications for the targeted diagnosis and treatment of cancer. PMID:22991319

  4. Sequential deconvolution input reconstruction

    NASA Astrophysics Data System (ADS)

    Bernal, Dionisio; Ussia, Alessia

    2015-01-01

    The reconstruction of inputs from measured outputs is examined. It is shown that the rank deficiency that arises in de-convolving non-collocated arrangements is associated with a kernel that is non-zero only over the part of the time axis where delay from wave propagation prevents uniqueness. Input deconvolution, therefore, follows in the same manner for collocated and non-collocated scenarios, collocation being the special case where the prediction lag can be zero. This paper illustrates that deconvolution carried out on a sliding window is a conditionally stable process and the condition for stability is derived. Examination of the Cramer-Rao Lower Bound of the inputs in frequency shows that the inference model should be formulated such that the spectra of the inputs to be reconstructed, and of the realized measurement noise, are within the model bandwidth. An expression for the error in the reconstructed input as a function of the noise sequence is developed and is used to control the regularization, when regularization is needed. The paper brings attention to the fact that finite dimensional models cannot display true dead time and that failure to recognize this matter has led to algorithms that, in general, propose to violate the physical constraints.

  5. A complementary dual-slope ADC with high frame rate and wide input range for fast X-ray imaging

    NASA Astrophysics Data System (ADS)

    Lee, Daehee; Cho, Minsik; Kang, Dong-Uk; Kim, Myung Soo; Kim, Hyunduk; Cho, Gyuseong

    2014-02-01

    The single-slope analog-to-digital converter (SS-ADC) is the most commonly used column-level ADC for high-speed industrial, complementary metal-oxide semiconductor (CMOS)-based X-ray image sensors because of its small chip area (the width of a pixel), its simple circuit structure, and its low power consumption. However, it generally has a long conversion time, so we propose an innovative design: a complimentary dual-slope ADC (CDS-ADC) that uses two opposite ramp signals instead of a single ramp to double the conversion speed. This CDS-ADC occupies only 15% more area than the original SS-ADC. A prototype 12-bit CDS-ADC and a 12-bit SS-ADC were fabricated using a 0.35-µm 1P 4M CMOS process. During comparison of the two, the measured maximum differential non-linearity (DNL) of the CDS-ADC was a 0.49 least significant bit (LSB), the maximum integral non-linearity (INL) was a 0.43 LSB, the effective number of bits (ENOB) was 9.18 bits, and the figure of merit (FOM) was 0.03 pJ/conversion. The total power consumption was 0.031 uW. The conversion time of the new CDS-ADC was half that of the SS-ADC. The proposed dual-slope concept can be extended to further multiply the conversion speed by using multiple pairs of dual-slope ramps.

  6. Synthesis and evaluation of ethyleneoxylated and allyloxylated chalcone derivatives for imaging of amyloid ? plaques by SPECT.

    PubMed

    Fuchigami, Takeshi; Yamashita, Yuki; Haratake, Mamoru; Ono, Masahiro; Yoshida, Sakura; Nakayama, Morio

    2014-05-01

    We report radioiodinated chalcone derivatives as new SPECT imaging probes for amyloid ? (A?) plaques. The monoethyleneoxy derivative 2 and allyloxy derivative 8 showed a high affinity for A?(1-42) aggregates with Ki values of 24 and 4.5 nM, respectively. Fluorescent imaging demonstrated that 2 and 8 clearly stained thioflavin-S positive A? plaques in the brain sections of Tg2576 transgenic mice. In vitro autoradiography revealed that [(125)I]2 displayed no clear accumulation toward A? plaques in the brain sections of Tg2576 mice, whereas the accumulation pattern of [(125)I]8 matched with the presence of A? plaques both in the brain sections of Tg2576 mice and an AD patient. In biodistribution studies using normal mice, [(125)I]2 showed preferable in vivo pharmacokinetics (4.82%ID/g at 2 min and 0.45%ID/g at 60 min), while [(125)I]8 showed only a modest brain uptake (1.62%ID/g at 2 min) with slow clearance (0.56%ID/g at 60 min). [(125)I]8 showed prospective binding properties for A? plaques, although further structural modifications are needed to improve the blood brain barrier permeability and washout from brain. PMID:24717291

  7. MRI-Derived 3-D-Printed Breast Phantom for Microwave Breast Imaging Validation

    PubMed Central

    Burfeindt, Matthew J.; Colgan, Timothy J.; Mays, R. Owen; Shea, Jacob D.; Behdad, Nader; Van Veen, Barry D.; Hagness, Susan C.

    2014-01-01

    We propose a 3-D-printed breast phantom for use in preclinical experimental microwave imaging studies. The phantom is derived from an MRI of a human subject; thus, it is anthropomorphic, and its interior is very similar to an actual distribution of fibroglandular tissues. Adipose tissue in the breast is represented by the solid plastic (printed) regions of the phantom, while fibroglandular tissue is represented by liquid-filled voids in the plastic. The liquid is chosen to provide a biologically relevant dielectric contrast with the printed plastic. Such a phantom enables validation of microwave imaging techniques. We describe the procedure for generating the 3-D-printed breast phantom and present the measured dielectric properties of the 3-D-printed plastic over the frequency range 0.5–3.5 GHz. We also provide an example of a suitable liquid for filling the fibroglandular voids in the plastic. PMID:25132808

  8. Hierarchy of Electronic Properties of Chemically Derived and Pristine Graphene Probed by Microwave Imaging

    SciTech Connect

    Kundhikanjana, W.

    2010-06-02

    Local electrical imaging using microwave impedance microscope is performed on graphene in different modalities, yielding a rich hierarchy of the local conductivity. The low-conductivity graphite oxide and its derivatives show significant electronic inhomogeneity. For the conductive chemical graphene, the residual defects lead to a systematic reduction of the microwave signals. In contrast, the signals on pristine graphene agree well with a lumped-element circuit model. The local impedance information can also be used to verify the electrical contact between overlapped graphene pieces.

  9. A Linear Method to Derive 3D Projective Invariants from 4 Uncalibrated Images

    PubMed Central

    Wang, YuanBin; Wang, XingWei; Zhang, Bin; Wang, Ying

    2014-01-01

    A well-known method proposed by Quan to compute projective invariants of 3D points uses six points in three 2D images. The method is nonlinear and complicated. It usually produces three possible solutions. It is noted previously that the problem can be solved directly and linearly using six points in five images. This paper presents a method to compute projective invariants of 3D points from four uncalibrated images directly. For a set of six 3D points in general position, we choose four of them as the reference basis and represent the other two points under this basis. It is known that the cross ratios of the coefficients of these representations are projective invariant. After a series of linear transformations, a system of four bilinear equations in the three unknown projective invariants is derived. Systems of nonlinear multivariable equations are usually hard to solve. We show that this form of equations can be solved linearly and uniquely. This finding is remarkable. It means that the natural configuration of the projective reconstruction problem might be six points and four images. The solutions are given in explicit formulas. PMID:24600317

  10. Vector image method for the derivation of elastostatic solutions for point sources in a plane layered medium. Part 1: Derivation and simple examples

    NASA Technical Reports Server (NTRS)

    Fares, Nabil; Li, Victor C.

    1986-01-01

    An image method algorithm is presented for the derivation of elastostatic solutions for point sources in bonded halfspaces assuming the infinite space point source is known. Specific cases were worked out and shown to coincide with well known solutions in the literature.

  11. Partially coherent optical processor for enhancement of partial second order derivatives of an image: Analysis and implementation

    NASA Astrophysics Data System (ADS)

    Flores, Jorge L.; Ferrari, José A.; Garcia-Torales, G.

    2011-12-01

    We present an optical processor capable to perform partial second derivatives of an image working with partially coherent illumination. The proposed system utilizes a liquid crystal display, onto which images to be derived are displayed. The method is based on the capacity of these devices to generate simultaneously a contrast reverted replica of the image displayed on it. A positive replica of original image is obtained when the LCD is between crossed polarizers, while the negative one is obtained with the LCD is between parallel polarizers. Since the LCD is a diffraction element, both polarizer arrangements may be simultaneously implemented, for example, in a 4 f optical processor using polarization filtering of the different diffraction orders. When three images (two replicas of original image displaced in opposite direction and the other one with contrast reverted and centered at the origin.) are imagined across a slightly defocused plane, one obtains an image with enhanced second derivatives in a given direction. No other incoherent (or partially coherent) optical system is presently known which can perform partial second-order derivatives of an image. Experimental results obtained are presented.

  12. Novel Positively Charged Nanoparticle Labeling for In Vivo Imaging of Adipose Tissue-Derived Stem Cells

    PubMed Central

    Yukawa, Hiroshi; Nakagawa, Shingo; Yoshizumi, Yasuma; Watanabe, Masaki; Saito, Hiroaki; Miyamoto, Yoshitaka; Noguchi, Hirofumi; Oishi, Koichi; Ono, Kenji; Sawada, Makoto; Kato, Ichiro; Onoshima, Daisuke; Obayashi, Momoko; Hayashi, Yumi; Kaji, Noritada; Ishikawa, Tetsuya; Hayashi, Shuji; Baba, Yoshinobu

    2014-01-01

    Stem cell transplantation has been expected to have various applications for regenerative medicine. However, in order to detect and trace the transplanted stem cells in the body, non-invasive and widely clinically available cell imaging technologies are required. In this paper, we focused on magnetic resonance (MR) imaging technology, and investigated whether the trimethylamino dextran-coated magnetic iron oxide nanoparticle -03 (TMADM-03), which was newly developed by our group, could be used for labeling adipose tissue-derived stem cells (ASCs) as a contrast agent. No cytotoxicity was observed in ASCs transduced with less than 100 µg-Fe/mL of TMADM-03 after a one hour transduction time. The transduction efficiency of TMADM-03 into ASCs was about four-fold more efficient than that of the alkali-treated dextran-coated magnetic iron oxide nanoparticle (ATDM), which is a major component of commercially available contrast agents such as ferucarbotran (Resovist), and the level of labeling was maintained for at least two weeks. In addition, the differentiation ability of ASCs labeled with TMADM-03 and their ability to produce cytokines such as hepatocyte growth factor (HGF), vascular endothelial growth factor (VEGF) and prostaglandin E2 (PGE2), were confirmed to be maintained. The ASCs labeled with TMADM-03 were transplanted into the left kidney capsule of a mouse. The labeled ASCs could be imaged with good contrast using a 1T MR imaging system. These data suggest that TMADM-03 can therefore be utilized as a contrast agent for the MR imaging of stem cells. PMID:25365191

  13. Novel positively charged nanoparticle labeling for in vivo imaging of adipose tissue-derived stem cells.

    PubMed

    Yukawa, Hiroshi; Nakagawa, Shingo; Yoshizumi, Yasuma; Watanabe, Masaki; Saito, Hiroaki; Miyamoto, Yoshitaka; Noguchi, Hirofumi; Oishi, Koichi; Ono, Kenji; Sawada, Makoto; Kato, Ichiro; Onoshima, Daisuke; Obayashi, Momoko; Hayashi, Yumi; Kaji, Noritada; Ishikawa, Tetsuya; Hayashi, Shuji; Baba, Yoshinobu

    2014-01-01

    Stem cell transplantation has been expected to have various applications for regenerative medicine. However, in order to detect and trace the transplanted stem cells in the body, non-invasive and widely clinically available cell imaging technologies are required. In this paper, we focused on magnetic resonance (MR) imaging technology, and investigated whether the trimethylamino dextran-coated magnetic iron oxide nanoparticle -03 (TMADM-03), which was newly developed by our group, could be used for labeling adipose tissue-derived stem cells (ASCs) as a contrast agent. No cytotoxicity was observed in ASCs transduced with less than 100 µg-Fe/mL of TMADM-03 after a one hour transduction time. The transduction efficiency of TMADM-03 into ASCs was about four-fold more efficient than that of the alkali-treated dextran-coated magnetic iron oxide nanoparticle (ATDM), which is a major component of commercially available contrast agents such as ferucarbotran (Resovist), and the level of labeling was maintained for at least two weeks. In addition, the differentiation ability of ASCs labeled with TMADM-03 and their ability to produce cytokines such as hepatocyte growth factor (HGF), vascular endothelial growth factor (VEGF) and prostaglandin E2 (PGE2), were confirmed to be maintained. The ASCs labeled with TMADM-03 were transplanted into the left kidney capsule of a mouse. The labeled ASCs could be imaged with good contrast using a 1T MR imaging system. These data suggest that TMADM-03 can therefore be utilized as a contrast agent for the MR imaging of stem cells. PMID:25365191

  14. A 1000-year sediment record of recurring hypoxia off the Mississippi River: The potential role of terrestrially-derived organic matter inputs

    USGS Publications Warehouse

    Swarzenski, P.W.; Campbell, P.L.; Osterman, L.E.; Poore, R.Z.

    2008-01-01

    A suite of inorganic and organic geochemical tracers and a low-oxygen tolerant benthic faunal index ('PEB') were measured in a 14C-dated 2+??m long gravity core collected on the Louisiana shelf adjacent to the Mississippi River delta to study potential millennium-scale low-oxygen events. Periodic down-core excursions in the PEB index throughout the core suggest recurring, natural bottom water low-oxygen events that extend back ??? 1000??14C years. Select trace element and biomarker distributions in these same sediments were examined as potential tracers of past hypoxic events and to help distinguish between marine versus terrestrial processes involved in organic carbon production. In discrete sediment horizons where the PEB index was elevated, redox-sensitive vanadium concentrations were consistently depleted, excursions in sedimentary ??13C suggest periodic, preferential terrestrial inputs, and the concentrations of two sterol biomarkers (sitosterol and ??-stigmasterol) also showed concurrent enrichments. If the PEB index successfully records ??? 1000??14C year-scale low-oxygen events, then the distribution of these geochemical tracers can be interpreted to corroborate the view that naturally occurring low-oxygen bottom water conditions have existed on the inner Louisiana continental shelf, not only in recent times, but also over at least the last 1000??14C years. These data support the general hypothesis that historic, low-oxygen bottom water conditions on the Louisiana shelf are likely tied to periods of increased fluvial discharge and associated wetland export in the absence of modern river levees. Enhanced river discharge and associated material export would both stimulate enhanced in situ organic carbon production and foster water column stratification. Such periodic elevated river flows during the last millennium can be linked to climate fluctuations and tropical storm activity. ?? 2008 Elsevier B.V. All rights reserved.

  15. Monitoring tropical cyclone intensity using wind fields derived from short-interval satellite images

    NASA Technical Reports Server (NTRS)

    Rodgers, E. B.; Gentry, R. C.

    1981-01-01

    Rapid scan visible images from the Visible Infrared Spin Scan Radiometer sensor on board SMS-2 and GOES-1 were used to derive high resolution upper and lower tropospheric environmental wind fields around three western Atlantic tropical cyclones (1975-78). These wind fields were used to derive upper and lower tropospheric areal mean relative vorticity and their differences, the net relative angular momentum balance and upper tropospheric mass outflow. These kinematic parameters were shown by studies using composite rawinsonde data to be strongly related to tropical cyclone formation and intensity changes. Also, the role of forced synoptic scale subsidence in tropical cyclone formation was examined. The studies showed that satellite-derived lower and upper tropospheric wind fields can be used to monitor and possibly predict tropical cyclone formation and intensity changes. These kinematic analyses showed that future changes in tropical cyclone intensity are mainly related to the "spin-up" of the storms by the net horizontal transport of relative angular momentum caused by convergence of cyclonic vorticity in the lower troposphere and to a lesser extent the divergence of anticyclone vorticity in the upper troposphere.

  16. Thermally activated delayed fluorescence of fluorescein derivative for time-resolved and confocal fluorescence imaging.

    PubMed

    Xiong, Xiaoqing; Song, Fengling; Wang, Jingyun; Zhang, Yukang; Xue, Yingying; Sun, Liangliang; Jiang, Na; Gao, Pan; Tian, Lu; Peng, Xiaojun

    2014-07-01

    Compared with fluorescence imaging utilizing fluorophores whose lifetimes are in the order of nanoseconds, time-resolved fluorescence microscopy has more advantages in monitoring target fluorescence. In this work, compound DCF-MPYM, which is based on a fluorescein derivative, showed long-lived luminescence (22.11 ?s in deaerated ethanol) and was used in time-resolved fluorescence imaging in living cells. Both nanosecond time-resolved transient difference absorption spectra and time-correlated single-photon counting (TCSPC) were employed to explain the long lifetime of the compound, which is rare in pure organic fluorophores without rare earth metals and heavy atoms. A mechanism of thermally activated delayed fluorescence (TADF) that considers the long wavelength fluorescence, large Stokes shift, and long-lived triplet state of DCF-MPYM was proposed. The energy gap (?EST) of DCF-MPYM between the singlet and triplet state was determined to be 28.36 meV by the decay rate of DF as a function of temperature. The ?E(ST) was small enough to allow efficient intersystem crossing (ISC) and reverse ISC, leading to efficient TADF at room temperature. The straightforward synthesis of DCF-MPYM and wide availability of its starting materials contribute to the excellent potential of the compound to replace luminescent lanthanide complexes in future time-resolved imaging technologies. PMID:24936960

  17. Noninvasive Detection and Imaging of Molecular Markers in Live Cardiomyocytes Derived from Human Embryonic Stem Cells

    PubMed Central

    Pascut, Flavius C.; Goh, Huey T.; Welch, Nathan; Buttery, Lee D.; Denning, Chris; Notingher, Ioan

    2011-01-01

    Raman microspectroscopy (RMS) was used to detect and image molecular markers specific to cardiomyocytes (CMs) derived from human embryonic stem cells (hESCs). This technique is noninvasive and thus can be used to discriminate individual live CMs within highly heterogeneous cell populations. Principal component analysis (PCA) of the Raman spectra was used to build a classification model for identification of individual CMs. Retrospective immunostaining imaging was used as the gold standard for phenotypic identification of each cell. We were able to discriminate CMs from other phenotypes with >97% specificity and >96% sensitivity, as calculated with the use of cross-validation algorithms (target 100% specificity). A comparison between Raman spectral images corresponding to selected Raman bands identified by the PCA model and immunostaining of the same cells allowed assignment of the Raman spectral markers. We conclude that glycogen is responsible for the discrimination of CMs, whereas myofibril proteins have a lesser contribution. This study demonstrates the potential of RMS for allowing the noninvasive phenotypic identification of hESC progeny. With further development, such label-free optical techniques may enable the separation of high-purity cell populations with mature phenotypes, and provide repeated measurements to monitor time-dependent molecular changes in live hESCs during differentiation in vitro. PMID:21190678

  18. QuickFF: A program for a quick and easy derivation of force fields for metal-organic frameworks from ab initio input.

    PubMed

    Vanduyfhuys, Louis; Vandenbrande, Steven; Verstraelen, Toon; Schmid, Rochus; Waroquier, Michel; Van Speybroeck, Veronique

    2015-05-15

    QuickFF is a software package to derive accurate force fields for isolated and complex molecular systems in a quick and easy manner. Apart from its general applicability, the program has been designed to generate force fields for metal-organic frameworks in an automated fashion. The force field parameters for the covalent interaction are derived from ab initio data. The mathematical expression of the covalent energy is kept simple to ensure robustness and to avoid fitting deficiencies as much as possible. The user needs to produce an equilibrium structure and a Hessian matrix for one or more building units. Afterward, a force field is generated for the system using a three-step method implemented in QuickFF. The first two steps of the methodology are designed to minimize correlations among the force field parameters. In the last step, the parameters are refined by imposing the force field parameters to reproduce the ab initio Hessian matrix in Cartesian coordinate space as accurate as possible. The method is applied on a set of 1000 organic molecules to show the easiness of the software protocol. To illustrate its application to metal-organic frameworks (MOFs), QuickFF is used to determine force fields for MIL-53(Al) and MOF-5. For both materials, accurate force fields were already generated in literature but they requested a lot of manual interventions. QuickFF is a tool that can easily be used by anyone with a basic knowledge of performing ab initio calculations. As a result, accurate force fields are generated with minimal effort. © 2015 Wiley Periodicals, Inc. PMID:25740170

  19. Monitoring seasonal state and mapping species in Alaskan taiga using imaging radar as input to CO[sub 2] flux models

    SciTech Connect

    Way, J.B.; Rignot, E.; McDonald, K.; Adams, P.; Viereck, L. (Jet Propulsion Lab., Pasadena, CA (United States) Institute of Northern Forestry, Fairbanks, AK (United States))

    1993-06-01

    Changes in the seasonal CO[sub 2] flux of the boreal forests may result from increased atmospheric CO[sub 2] concentrations and associated atmospheric warming. To monitor this potential change, a combination of remote sensing information and ecophysiological models are required. In this paper we address the use of synthetic aperture radar (SAR) data to provide some of the input to the ecophysiological models: forest type, freeze/thaw state which limits the growing season for conifers, and leaf on/off state which limits the growing season for deciduous species. AIRSAR data collected in March 1988 during an early thaw event and May 1991 during spring breakup are used to generate species maps and to determine the sensitivity of SAR to canopy freeze/thaw transitions. These data are also used to validate a microwave scattering model which is then used to determine the sensitivity of SAR to leaf on/off and soil freeze/thaw transitions. Finally, a CO[sub 2] flux algorithm which utilizes SAR data and an ecophysiological model to estimate CO[sub 2] flux is presented. CO[sub 2] flux maps are generated from which areal estimates of CO[sub 2] flux are derived. This work was carried out at the Jet Propulsion Laboratory under contract to the NASA.

  20. (abstract) Monitoring Seasonal State and Mapping Species in Alaskan Taiga Using Imaging Radar as Input to CO(sub 2) Flux Models

    NASA Technical Reports Server (NTRS)

    Way, J. B.; Rignot, E.; McDonald, K.; Adams, P.; Viereck, L.

    1993-01-01

    Changes in the seasonal CO(sub 2) flux of the boreal forests may result from increased atmospheric CO(sub 2) concentrations and associated atmospheric warming. To monitor this potential change, a combination of remote sensing information and ecophysiological models are required. In this paper we address the use of synthetic aperture radar (SAR) data to provide some of the input to the ecophysiological models: forest type, freeze/thaw state which limits the growing season for conifers, and leaf on/off state which limits the growing season for deciduous species. AIRSAR data collected in March 1988 during an early thaw event and May 1991 during spring breakup are used to generate species maps and to determine the sensitivity of SAR to canopy freeze/thaw transitions. These data are also used to validate a microwave scattering model which is then used to determine the sensitivity of SAR to leaf on/off and soil freeze/thaw transitions. Finally, a CO(sub 2) flux algorithm which utilizes SAR data and an ecophysiological model to estimate CO(sub 2) flux is presented. CO(sub 2) flux maps are generated from which areal estimates of CO(sub 2) flux are derived.

  1. Arterial input function of an optical tracer for dynamic contrast enhanced imaging can be determined from pulse oximetry oxygen saturation measurements

    NASA Astrophysics Data System (ADS)

    Elliott, Jonathan T.; Wright, Eric A.; Tichauer, Kenneth M.; Diop, Mamadou; Morrison, Laura B.; Pogue, Brian W.; Lee, Ting-Yim; St. Lawrence, Keith

    2012-12-01

    In many cases, kinetic modeling requires that the arterial input function (AIF)—the time-dependent arterial concentration of a tracer—be characterized. A straightforward method to measure the AIF of red and near-infrared optical dyes (e.g., indocyanine green) using a pulse oximeter is presented. The method is motivated by the ubiquity of pulse oximeters used in both preclinical and clinical applications, as well as the gap in currently available technologies to measure AIFs in small animals. The method is based on quantifying the interference that is observed in the derived arterial oxygen saturation (SaO2) following a bolus injection of a light-absorbing dye. In other words, the change in SaO2 can be converted into dye concentration knowing the chromophore-specific extinction coefficients, the true arterial oxygen saturation, and total hemoglobin concentration. A simple error analysis was performed to highlight potential limitations of the approach, and a validation of the method was conducted in rabbits by comparing the pulse oximetry method with the AIF acquired using a pulse dye densitometer. Considering that determining the AIF is required for performing quantitative tracer kinetics, this method provides a flexible tool for measuring the arterial dye concentration that could be used in a variety of applications.

  2. Input impedance of microstrip antennas

    NASA Technical Reports Server (NTRS)

    Deshpande, M. D.; Bailey, M. C.

    1982-01-01

    Using Richmond's reaction integral equation, an expression is derived for the input impedance of microstrip patch antennas excited by either a microstrip line or a coaxial probe. The effects of the finite substrate thickness, a dielectric protective cover, and associated surface waves are properly included by the use of the exact dyadic Green's function. Using the present formulation the input impedance of a rectangular microstrip antenna is determined and compared with experimental and earlier calculated results.

  3. A comparison of dynamic contrast-enhanced CT and MR imaging-derived measurements in patients with cervical cancer.

    PubMed

    Kim, Sun Mo; Haider, Masoom A; Milosevic, Michael; Yeung, Ivan W T

    2013-03-01

    This work is to compare the kinetic parameters derived from the DCE-CT and -MR data of a group of 37 patients with cervical cancer. The modified Tofts model and the reference tissue method were applied to estimate kinetic parameters. In the MR kinetic analyses using the modified Tofts model for each patient data set, both the arterial input function (AIF) measured from DCE-MR images and a population-averaged AIF from the literature were applied to the analyses, while the measured AIF was used for the CT kinetic analysis. The kinetic parameters obtained from both modalities were compared. Significant moderate correlations were found in modified Tofts parameters [volume transfer constant(K(trans) ) and rate constant (k(ep) )] between CT and MR analysis for MR with the measured AIFs (R = 0·45, P<0·01 and R = 0·40, P<0·01 in high-K(trans) region; R = 0·38, P<0·01 and R = 0·80, P<0·01 in low-K(trans) region) as well as with the population-averaged AIF (R = 0·59, P<0·01 and R = 0·62, P<0·01 in high-K(trans) region; R = 0·50, P<0·01 and R = 0·63, P<0·01 in low-K(trans) region), respectively. In addition, from the Bland-Altman plot analysis, it was found that the systematic biases (the mean difference) between the modalities were drastically reduced in magnitude by adopting the population-averaged AIF for the MR analysis instead of the measured ones (from 51·5% to 18·9% for K(trans) and from 21·7% to 4·1% for k(ep) in high-K(trans) region; from 73·0% to 29·4% for K(trans) and from 63·4% to 24·5% for k(ep) in low-K(trans) region). The preliminary results showed the feasibility in the interchangeable use of the two imaging modalities in assessing cervical cancers. PMID:23383694

  4. Soil moisture retrieval from SAR images as a calibration tool for soil moisture index derived from thermal inertia with MODIS images

    NASA Astrophysics Data System (ADS)

    Notarnicola, C.; Ventura, B.; Pettinato, S.; Santi, E.; Zebisch, M.

    2009-09-01

    This paper aims at identifying an operational methodology to derive soil moisture status from optical images by using soil moisture values derived from SAR images as a calibration tool . In the first part of the paper, an algorithm based on Bayesian techniques for the retrieval of soil moisture from C-band SAR images is presented. The algorithm is composed of two modules, one for bare soil and the other for vegetated soil which includes also the use of optical images in order to take into account the vegetation contribution. soil moisture values retrieved from images are then used as a calibration tool for a soil moisture index derived from MODIS images. In this case, the method to estimate soil moisture index from optical and thermal images is based on the calculation of the Apparent Thermal Inertia (ATI). ATI is considered as an approximate (apparent) value of the thermal inertia and is obtained from spectral measurements of the albedo and the diurnal temperature range. soil moisture estimated from SAR images and the ATI are compared in order to find a calibration curve which should cover the entire soil moisture values from saturation to residual moisture values. For the calibration experiment, three main sites were chosen which exhibit different landscape and climatic characteristics. The Basento basin is located in Southern Italy and is characterized by long period of droughts. The Scrivia valley is flat alluvial plain measuring situated close to the confluence of the Scrivia and Po rivers in Northern Italy. The Cordevole watershed, located at the foothill of Mount Sella in Northern Italy is mainly covered by grassland and it was selected because of its relatively smooth topography. The first results indicate a good correlation between ATI and the soil moisture values derived both from measurements and estimated from SAR images.

  5. A study on the topological derivative-based imaging of thin electromagnetic inhomogeneities in limited-aperture problems

    NASA Astrophysics Data System (ADS)

    Ahn, Chi Young; Jeon, Kiwan; Ma, Yong-Ki; Park, Won-Kwang

    2014-10-01

    The topological derivative-based non-iterative imaging algorithm has demonstrated its applicability in limited-aperture inverse scattering problems. However, this has been confirmed through many experimental simulation results, and the reason behind this applicability has not been satisfactorily explained. In this paper, we identify the mathematical structure and certain properties of topological derivatives for the imaging of two-dimensional crack-like thin penetrable electromagnetic inhomogeneities that are completely embedded in a homogeneous material. To this end, we establish a relationship with an infinite series of Bessel functions of integer order of the first kind. Based on the derived structure, we discover a necessary condition for applying topological derivatives in limited-aperture inverse scattering problems, and thus confirm why topological derivatives can be applied. Furthermore, we analyze the structure of multi-frequency topological derivative, and identify why this improves the single-frequency topological derivative in limited-aperture inverse scattering problems. Various numerical simulations are conducted with noisy data, and the results support the derived structure and exhibit certain properties of single- and multi-frequency topological derivatives.

  6. Plasma distribution in Mercury's magnetosphere derived from MESSENGER Magnetometer and Fast Imaging Plasma Spectrometer observations

    NASA Astrophysics Data System (ADS)

    Korth, Haje; Anderson, Brian J.; Gershman, Daniel J.; Raines, Jim M.; Slavin, James A.; Zurbuchen, Thomas H.; Solomon, Sean C.; McNutt, Ralph L.

    2014-04-01

    We assess the statistical spatial distribution of plasma in Mercury's magnetosphere from observations of magnetic pressure deficits and plasma characteristics by the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft. The statistical distributions of proton flux and pressure were derived from 10 months of Fast Imaging Plasma Spectrometer (FIPS) observations obtained during the orbital phase of the MESSENGER mission. The Magnetometer-derived pressure distributions compare favorably with those deduced from the FIPS observations at locations where depressions in the magnetic field associated with the presence of enhanced plasma pressures are discernible in the Magnetometer data. The magnitudes of the magnetic pressure deficit and the plasma pressure agree on average, although the two measures of plasma pressure may deviate for individual events by as much as a factor of ~3. The FIPS distributions provide better statistics in regions where the plasma is more tenuous and reveal an enhanced plasma population near the magnetopause flanks resulting from direct entry of magnetosheath plasma into the low-latitude boundary layer of the magnetosphere. The plasma observations also exhibit a pronounced north-south asymmetry on the nightside, with markedly lower fluxes at low altitudes in the northern hemisphere than at higher altitudes in the south on the same field line. This asymmetry is consistent with particle loss to the southern hemisphere surface during bounce motion in Mercury's offset dipole magnetic field.

  7. Magnetic resonance velocity imaging derived pressure differential using control volume analysis

    PubMed Central

    2011-01-01

    Background Diagnosis and treatment of hydrocephalus is hindered by a lack of systemic understanding of the interrelationships between pressures and flow of cerebrospinal fluid in the brain. Control volume analysis provides a fluid physics approach to quantify and relate pressure and flow information. The objective of this study was to use control volume analysis and magnetic resonance velocity imaging to non-invasively estimate pressure differentials in vitro. Method A flow phantom was constructed and water was the experimental fluid. The phantom was connected to a high-resolution differential pressure sensor and a computer controlled pump producing sinusoidal flow. Magnetic resonance velocity measurements were taken and subsequently analyzed to derive pressure differential waveforms using momentum conservation principles. Independent sensor measurements were obtained for comparison. Results Using magnetic resonance data the momentum balance in the phantom was computed. The measured differential pressure force had amplitude of 14.4 dynes (pressure gradient amplitude 0.30 Pa/cm). A 12.5% normalized root mean square deviation between derived and directly measured pressure differential was obtained. These experiments demonstrate one example of the potential utility of control volume analysis and the concepts involved in its application. Conclusions This study validates a non-invasive measurement technique for relating velocity measurements to pressure differential. These methods may be applied to clinical measurements to estimate pressure differentials in vivo which could not be obtained with current clinical sensors. PMID:21414222

  8. Synthesis and Characterization of Water-Soluble Polythiophene Derivatives for Cell Imaging

    NASA Astrophysics Data System (ADS)

    Wang, Fengyan; Li, Meng; Wang, Bing; Zhang, Jiangyan; Cheng, Yongqiang; Liu, Libing; Lv, Fengting; Wang, Shu

    2015-01-01

    In this work, four water-soluble polythiophene derivatives (PT, PT-DDA, PT-ADA, and PT-ADA-PPR) with different pendant moieties were synthesized via oxidative copolymerization by FeCl3. By increasing the hydrophobic ability of side chain moieties, there is a gradually blue shift for the maximum absorption wavelength and red shift for the maximum emission wavelength, a reducing trend for fluorescence quantum yields, a growing trend for Stokes shift, and an increasing trend for the mean sizes in the order of PT, PT-ADA, and PT-DDA. All the synthesized polymers show low toxicity and good photostability and accumulate in the lysosomes of A549 cells. Furthermore, the introduction of porphyrin group to PT-ADA side chain (PT-ADA-PPR) broadens the absorption and emission ranges of PT-ADA. PT-ADA-PPR could be excited at two different excitation wavelengths (488 nm and 559 nm) and exhibits two emission pathways, and dual-color fluorescence images (orange and red) of PT-ADA-PPR accumulated in A549 cells are observed. Thus, PT-ADA-PPR could be used as an excellent dual-color fluorescent and lysosome-specific imaging material.

  9. Synthesis and characterization of water-soluble polythiophene derivatives for cell imaging.

    PubMed

    Wang, Fengyan; Li, Meng; Wang, Bing; Zhang, Jiangyan; Cheng, Yongqiang; Liu, Libing; Lv, Fengting; Wang, Shu

    2015-01-01

    In this work, four water-soluble polythiophene derivatives (PT, PT-DDA, PT-ADA, and PT-ADA-PPR) with different pendant moieties were synthesized via oxidative copolymerization by FeCl3. By increasing the hydrophobic ability of side chain moieties, there is a gradually blue shift for the maximum absorption wavelength and red shift for the maximum emission wavelength, a reducing trend for fluorescence quantum yields, a growing trend for Stokes shift, and an increasing trend for the mean sizes in the order of PT, PT-ADA, and PT-DDA. All the synthesized polymers show low toxicity and good photostability and accumulate in the lysosomes of A549 cells. Furthermore, the introduction of porphyrin group to PT-ADA side chain (PT-ADA-PPR) broadens the absorption and emission ranges of PT-ADA. PT-ADA-PPR could be excited at two different excitation wavelengths (488?nm and 559?nm) and exhibits two emission pathways, and dual-color fluorescence images (orange and red) of PT-ADA-PPR accumulated in A549 cells are observed. Thus, PT-ADA-PPR could be used as an excellent dual-color fluorescent and lysosome-specific imaging material. PMID:25557020

  10. Ladar image recognition using synthetically derived discrete phase-amplitude filters in an optical correlator

    NASA Astrophysics Data System (ADS)

    Calloway, David; Goldstein, Dennis H.

    2002-03-01

    Correlation filters using computer-generated laser radar imagery have been constructed. This paper describes how the filters were constructed and reports correlating result with the synthetic imagery used in the training set, with real ladar imagery of equivalent targets, and with real ladar imagery of false targets. A comprehensive set of images was collected on the Eglin Test Range using a direct-detect scanning ladar mounted on a 100-meter tower. Various targets were placed on a large turntable and ladar range and intensity data were collected at various aspect and depression angles. The Irma scene generation software package was then used to generate synthetic ladar imagery for these targets at a similar set of range, aspect, and depression angles. Several different techniques were used to generate the filters and to process the imagery used in this research. This paper describes one of the most successful techniques. The paper provides details on the iterative approach used to generate composite filters, describes how they were applied, and compares the results produced from synthetic and real target imagery. This experiment was considered a success since the synthetically derived filters were capable of recognizing images of real targets while rejecting false targets.

  11. Isomerism in Benzyl-DOTA Derived Bifunctional Chelators: Implications for Molecular Imaging.

    PubMed

    Payne, Katherine M; Woods, Mark

    2015-02-18

    The bifunctional chelator IB-DOTA has found use in a range of biomedical applications given its ability to chelate many metal ions, but in particular the lanthanide(III) ions. Gd(3+) in particular is of interest in the development of new molecular imaging agents for MRI and is highly suitable for chelation by IB-DOTA. Given the long-term instability of the aryl isothiocyanate functional group we have used the more stable nitro derivative (NB-DOTA) to conduct a follow-up study of some of our previous work on the coordination chemistry of chelates of these BFCs. Using a combination of NMR and HPLC to study the Eu(3+) and Yb(3+) chelates of NB-DOTA, we have demonstrated that this ligand will produce two discrete regioisomeric chelates at the point at which the metal ion is introduced into the BFC. These regioisomers are defined by the position of the benzylic substituent on the macrocyclic ring: adopting an equatorial position either at the corner or the side of the [3333] ring conformation. These regioisomers are incapable of interconversion and are distinct, separate structures with different SAP/TSAP ratios. The side isomer exhibits an increased population of the TSAP isomer, pointing to more rapid water exchange kinetics in this regioisomer. This has potential ramifications for the use of these two regioisomers of Gd(3+)-BFC chelates in MRI applications. We have also found that, remarkably, there is little or no freedom of rotation about the first single bond extending from the macrocyclic ring to the benzylic substituent. Since this is the linkage through which the chelate is conjugated to the remainder of the molecular imaging probe, this result implies that there may be reduced local rotation of the Gd(3+) chelate within a molecular imaging probe. This implies that this type of BFC could exhibit higher relaxivities than other types of BFC. PMID:25635382

  12. Tumor Imaging and Targeting Potential of an Hsp70-Derived 14-Mer Peptide

    PubMed Central

    Oellinger, Rupert; Breuninger, Stephanie; Rad, Roland; Pockley, Alan G.; Multhoff, Gabriele

    2014-01-01

    Background We have previously used a unique mouse monoclonal antibody cmHsp70.1 to demonstrate the selective presence of a membrane-bound form of Hsp70 (memHsp70) on a variety of leukemia cells and on single cell suspensions derived from solid tumors of different entities, but not on non-transformed cells or cells from corresponding ’healthy‘ tissue. This antibody can be used to image tumors in vivo and target them for antibody-dependent cellular cytotoxicity. Tumor-specific expression of memHsp70 therefore has the potential to be exploited for theranostic purposes. Given the advantages of peptides as imaging and targeting agents, this study assessed whether a 14-mer tumor penetrating peptide (TPP; TKDNNLLGRFELSG), the sequence of which is derived from the oligomerization domain of Hsp70 which is expressed on the cell surface of tumor cells, can also be used for targeting membrane Hsp70 positive (memHsp70+) tumor cells, in vitro. Methodology/Principal Findings The specificity of carboxy-fluorescein (CF-) labeled TPP (TPP) to Hsp70 was proven in an Hsp70 knockout mammary tumor cell system. TPP specifically binds to different memHsp70+ mouse and human tumor cell lines and is rapidly taken up via endosomes. Two to four-fold higher levels of CF-labeled TPP were detected in MCF7 (82% memHsp70+) and MDA-MB-231 (75% memHsp70+) cells compared to T47D cells (29% memHsp70+) that exhibit a lower Hsp70 membrane positivity. After 90 min incubation, TPP co-localized with mitochondrial membranes in memHsp70+ tumors. Although there was no evidence that any given vesicle population was specifically localized, fluorophore-labeled cmHsp70.1 antibody and TPP preferentially accumulated in the proximity of the adherent surface of cultured cells. These findings suggest a potential association between membrane Hsp70 expression and cytoskeletal elements that are involved in adherence, the establishment of intercellular synapses and/or membrane reorganization. Conclusions/Significance This study demonstrates the specific binding and rapid internalization of TPP by tumor cells with a memHsp70+ phenotype. TPP might therefore have potential for targeting and imaging the large proportion of tumors (?50%) that express memHsp70. PMID:25165986

  13. An operational software tool for the analysis of coronagraph images: Determining CME parameters for input into the WSA-Enlil heliospheric model

    NASA Astrophysics Data System (ADS)

    Millward, G.; Biesecker, D.; Pizzo, V.; Koning, C. A.

    2013-02-01

    Coronal mass ejections (CMEs)—massive explosions of dense plasma that originate in the lower solar atmosphere and propagate outward into the solar wind—are the leading cause of significant space weather effects within Earth's environment. Computational models of the heliosphere such as WSA-Enlil offer the possibility of predicting whether a given CME will become geo-effective and, if so, the likely time of arrival at Earth. To be meaningful, such a forecast model is dependent upon accurately characterizing key parameters for the CME, notably its speed and direction of propagation, and its angular width. Studies by Zhao et al. (2002) and Xie et al. (2004) suggest that these key CME parameters can be deduced from geometric analysis of the elliptical "halo" forms observed in coronagraph images on spacecraft such as the Solar and Heliospheric Observatory (SOHO) and which result from a CME whose propagation is roughly toward or away from the observer. Both studies assume that the CME presents a circular cross-section and maintains a constant angular width during its radial expansion, the so called "cone model." Development work at the NOAA Space Weather Prediction Center (SWPC) has been concerned with building and testing software tools to allow forecasters to determine these CME parameters routinely within an operational context, a key aspect of transitioning the WSA-Enlil heliospheric model into operations at the National Weather Service. We find "single viewpoint" cone analysis, while a useful start, to be highly problematic in many real-world situations. In particular, it is extremely difficult to establish objectively the correct ellipse that should be applied to a given halo form and that small changes in the exact ellipse chosen can lead to large differences in the deduced CME parameters. The inaccuracies in the technique are particularly evident for analysis of the "nearly circular" elliptical forms which result from CMEs that are propagating directly toward the observer and are therefore the most likely to be geo-effective. In working to resolve this issue we have developed a new three-dimensional (3-D) graphics-based analysis system which seeks to reduce inaccuracies by analyzing a CME using coronagraph images taken concurrently by SOHO and also by the two Solar TErrestrial RElations Observatory (STEREO) spacecraft, which provide additional viewing locations well away from the Sun-Earth line. The resulting "three view" technique has led to the development of the CME Analysis Tool (CAT), an operational software system in routine use at the SWPC as the primary means to determine CME parameters for input into the WSA-Enlil model. Results from the operational WSA-Enlil system are presented: utilizing CAT to provide CME input parameters, we show that, during the first year of operations at SWPC, the WSA-Enlil model has forecasted the arrival of CMEs at Earth with an average error 7.5 h.

  14. Molecular and Magnetic Resonance Imaging of Human Embryonic Stem Cell–Derived Neural Stem Cell Grafts in Ischemic Rat Brain

    Microsoft Academic Search

    Marcel M Daadi; Zongjin Li; Ahmet Arac; Brad A Grueter; Marc Sofilos; Robert C Malenka; Joseph C Wu; Gary K Steinberg

    2009-01-01

    Real-time imaging of transplanted stem cells is essential for understanding their interactions in vivo with host environments, for tracking cell fate and function and for successful delivery and safety monitoring in the clinical setting. In this study, we used bioluminescence (BLI) and magnetic resonance imaging (MRI) to visualize the fate of grafted human embryonic stem cell (hESC)–derived human neural stem

  15. Image Enlargement Based on Low to High-frequency Components Mapping Derived from Self-decomposed Images

    Microsoft Academic Search

    Hideaki Kawano; Noriaki Suetake; Byungki Cha; Takashi Aso

    Due to the wide diffusion of multimedia applications and wide area screens-for example, video walls—the problem of image size\\u000a conversion (especially image enlargement) has significantly increased in importance. Various image enlargement methods have\\u000a been proposed so far [1], and they are split into multi-frame image enlargement methods and single-frame methods.\\u000a \\u000a The multi-frame image enlargement is a process of combining multiple

  16. Imer-product array processor for retrieval of stored images represented by bipolar binary (+1,-1) pixels using partial input trinary pixels represented by (+1,-1)

    NASA Technical Reports Server (NTRS)

    Liu, Hua-Kuang (Inventor); Awwal, Abdul A. S. (Inventor); Karim, Mohammad A. (Inventor)

    1993-01-01

    An inner-product array processor is provided with thresholding of the inner product during each iteration to make more significant the inner product employed in estimating a vector to be used as the input vector for the next iteration. While stored vectors and estimated vectors are represented in bipolar binary (1,-1), only those elements of an initial partial input vector that are believed to be common with those of a stored vector are represented in bipolar binary; the remaining elements of a partial input vector are set to 0. This mode of representation, in which the known elements of a partial input vector are in bipolar binary form and the remaining elements are set equal to 0, is referred to as trinary representation. The initial inner products corresponding to the partial input vector will then be equal to the number of known elements. Inner-product thresholding is applied to accelerate convergence and to avoid convergence to a negative input product.

  17. Imaging of hydrogen peroxide generation in cultured cells using dichlorofluorescein derivatives

    NASA Astrophysics Data System (ADS)

    Hockberger, Philip E.; Ahmed, Mohammed S.; Skimina, Timothy A.; Lee, Christopher; Hung, Wu-Yen; Siddique, Tippu

    1996-05-01

    There is growing evidence that generation of reactive oxygen molecules (e.g., hydrogen peroxide, superoxide, hydroxyl and nitric oxide radicals) plays an important role in cell death. In this report we evaluated the effectiveness of the membrane permeable probe carboxy- dichlorodihydrofluorescein diacetate acetoxymethyl ester (C-DCDHF-DA-AM) for imaging the production of H2O2 in cultured cells. We examined the properties of three derivatives of the ester in saline droplets and compared the results with responses recorded from cells loaded with the ester. Results indicated that fluorescence was generated in cells and droplets by a photo-oxidative process involving H2O2. Videomicroscopy demonstrated that the cellular responses originated in small vesicles (presumably peroxisomes), with large responses filling the cytosol and enveloping the nucleus. We interpreted these responses as due to light-induced activation of flavin-containing oxidases, which generate H2O2 in peroxisomes, followed by diffusion of H2O2 throughout the cell. Escape of H2O2 from peroxisomes into Fe2+-containing compartments could have dire consequences on cell viability due to the production of hydroxyl free radicals. Such a mechanism could underly the phototoxic effects of visible light on cultured cells.

  18. Preclinical Derivation and Imaging of Autologously Transplanted Canine Induced Pluripotent Stem Cells*

    PubMed Central

    Lee, Andrew S.; Xu, Dan; Plews, Jordan R.; Nguyen, Patricia K.; Nag, Divya; Lyons, Jennifer K.; Han, Leng; Hu, Shijun; Lan, Feng; Liu, Junwei; Huang, Mei; Narsinh, Kazim H.; Long, Charles T.; de Almeida, Patricia E.; Levi, Benjamin; Kooreman, Nigel; Bangs, Charles; Pacharinsak, Cholawat; Ikeno, Fumiaki; Yeung, Alan C.; Gambhir, Sanjiv S.; Robbins, Robert C.; Longaker, Michael T.; Wu, Joseph C.

    2011-01-01

    Derivation of patient-specific induced pluripotent stem cells (iPSCs) opens a new avenue for future applications of regenerative medicine. However, before iPSCs can be used in a clinical setting, it is critical to validate their in vivo fate following autologous transplantation. Thus far, preclinical studies have been limited to small animals and have yet to be conducted in large animals that are physiologically more similar to humans. In this study, we report the first autologous transplantation of iPSCs in a large animal model through the generation of canine iPSCs (ciPSCs) from the canine adipose stromal cells and canine fibroblasts of adult mongrel dogs. We confirmed pluripotency of ciPSCs using the following techniques: (i) immunostaining and quantitative PCR for the presence of pluripotent and germ layer-specific markers in differentiated ciPSCs; (ii) microarray analysis that demonstrates similar gene expression profiles between ciPSCs and canine embryonic stem cells; (iii) teratoma formation assays; and (iv) karyotyping for genomic stability. Fate of ciPSCs autologously transplanted to the canine heart was tracked in vivo using clinical positron emission tomography, computed tomography, and magnetic resonance imaging. To demonstrate clinical potential of ciPSCs to treat models of injury, we generated endothelial cells (ciPSC-ECs) and used these cells to treat immunodeficient murine models of myocardial infarction and hindlimb ischemia. PMID:21719696

  19. Preclinical derivation and imaging of autologously transplanted canine induced pluripotent stem cells.

    PubMed

    Lee, Andrew S; Xu, Dan; Plews, Jordan R; Nguyen, Patricia K; Nag, Divya; Lyons, Jennifer K; Han, Leng; Hu, Shijun; Lan, Feng; Liu, Junwei; Huang, Mei; Narsinh, Kazim H; Long, Charles T; de Almeida, Patricia E; Levi, Benjamin; Kooreman, Nigel; Bangs, Charles; Pacharinsak, Cholawat; Ikeno, Fumiaki; Yeung, Alan C; Gambhir, Sanjiv S; Robbins, Robert C; Longaker, Michael T; Wu, Joseph C

    2011-09-16

    Derivation of patient-specific induced pluripotent stem cells (iPSCs) opens a new avenue for future applications of regenerative medicine. However, before iPSCs can be used in a clinical setting, it is critical to validate their in vivo fate following autologous transplantation. Thus far, preclinical studies have been limited to small animals and have yet to be conducted in large animals that are physiologically more similar to humans. In this study, we report the first autologous transplantation of iPSCs in a large animal model through the generation of canine iPSCs (ciPSCs) from the canine adipose stromal cells and canine fibroblasts of adult mongrel dogs. We confirmed pluripotency of ciPSCs using the following techniques: (i) immunostaining and quantitative PCR for the presence of pluripotent and germ layer-specific markers in differentiated ciPSCs; (ii) microarray analysis that demonstrates similar gene expression profiles between ciPSCs and canine embryonic stem cells; (iii) teratoma formation assays; and (iv) karyotyping for genomic stability. Fate of ciPSCs autologously transplanted to the canine heart was tracked in vivo using clinical positron emission tomography, computed tomography, and magnetic resonance imaging. To demonstrate clinical potential of ciPSCs to treat models of injury, we generated endothelial cells (ciPSC-ECs) and used these cells to treat immunodeficient murine models of myocardial infarction and hindlimb ischemia. PMID:21719696

  20. Kinetic modelling using basis functions derived from two-tissue compartmental models with a plasma input function: general principle and application to [18F]fluorodeoxyglucose positron emission tomography.

    PubMed

    Hong, Young T; Fryer, Tim D

    2010-05-15

    A kinetic modelling method for the determination of influx constant, Ki is given that utilises basis functions derived from plasma input two-tissue compartmental models (BAFPIC). Two forms of the basis functions are given: BAFPICI with k4=0 (no product loss) and BAFPICR with k4 non-zero. Simulations were performed using literature rate constant values for [18F]fluorodeoxyglucose (FDG) in both normal and abnormal brain pathology. Both homogeneous and heterogeneous tissues were simulated and this data was also used as input for other methods commonly used to determine Ki: non-linear least squares compartmental modelling (NLLS), autoradiographic method and Patlak-Gjedde graphical analysis (PGA). The four methods were also compared for real FDG positron emission tomography (PET) data. For both k4=0 and k4 non-zero simulated data BAFPIC had the best bias properties of the four methods. The autoradiographic method was always the best for variability but BAFPICI had lower variability than PGA and NLLS. For non-zero k4 data, the variance of BAFPICR was inferior to PGA but still significantly superior to NLLS. Ki maps calculated from real data substantiate the simulation results, with BAFPICI having lower noise than PGA. Voxel Ki values from BAFPICI correlated well with those from PGA (r2=0.989). BAFPIC is easy to implement and combines low bias with good noise properties for voxel-wise determination of Ki for FDG. BAFPIC is suitable for determining Ki for other tracers well characterised by a serial two-tissue compartment model and has the advantage of also producing values for individual kinetic constants and blood volume. PMID:20156574

  1. Mapping and monitoring changes in vegetation communities of Jasper Ridge, CA, using spectral fractions derived from AVIRIS images

    NASA Technical Reports Server (NTRS)

    Sabol, Donald E., Jr.; Roberts, Dar A.; Adams, John B.; Smith, Milton O.

    1993-01-01

    An important application of remote sensing is to map and monitor changes over large areas of the land surface. This is particularly significant with the current interest in monitoring vegetation communities. Most of traditional methods for mapping different types of plant communities are based upon statistical classification techniques (i.e., parallel piped, nearest-neighbor, etc.) applied to uncalibrated multispectral data. Classes from these techniques are typically difficult to interpret (particularly to a field ecologist/botanist). Also, classes derived for one image can be very different from those derived from another image of the same area, making interpretation of observed temporal changes nearly impossible. More recently, neural networks have been applied to classification. Neural network classification, based upon spectral matching, is weak in dealing with spectral mixtures (a condition prevalent in images of natural surfaces). Another approach to mapping vegetation communities is based on spectral mixture analysis, which can provide a consistent framework for image interpretation. Roberts et al. (1990) mapped vegetation using the band residuals from a simple mixing model (the same spectral endmembers applied to all image pixels). Sabol et al. (1992b) and Roberts et al. (1992) used different methods to apply the most appropriate spectral endmembers to each image pixel, thereby allowing mapping of vegetation based upon the the different endmember spectra. In this paper, we describe a new approach to classification of vegetation communities based upon the spectra fractions derived from spectral mixture analysis. This approach was applied to three 1992 AVIRIS images of Jasper Ridge, California to observe seasonal changes in surface composition.

  2. Synthesis, Radiolabeling and Biological Evaluation of 99mTc-labeled Deoxyglucose Derivatives for Molecular Imaging

    PubMed Central

    Sadeghzadeh, Masoud; Charkhlooiea, Ghorbanali; Johari Daha, Fariba

    2013-01-01

    Two deoxyglucose (DG) derivatives, (?,?)-2-deoxy-2-amino(ethylcarbamate)-D-glucose (ECB-DG) and (?,?)-2-deoxy-2-amino(1,2-dihydroxypropyl)-D-glucose (DHP-DG), were synthesized and radiolabeled successfully with [99mTc(H2O)3(CO)3]+ complex. [99mTc]-ECB-DG and [99mTc]-DHP-DG complexes were prepared (96% and 93% radiochemical purities respectively) by using 46 mCi of Na99mTcO4 in 1 mL saline. Radio-HPLC analysis of [99mTc]- ECB-DG at pH = 7.4, revealed that labeling with 99mTc leads to formation of one radiochemical species with tR = 381 second. Three radiochemical species, Na99mTcO4, [99mTc]-DHP-DG and [99mTc(H2O)3(CO)3]+ complexes with tR = 342 sec, tR = 567 sec and tR = 1586 sec respectively, were obtained when [99mTc]-DHP-DG complex evaluated by HPLC. Biodistribution of two complexes were studied on normal mice at 10, 30 and 60 min post-injections. Compared to the 18F-FDG, [99mTc]-ECB-DG displayed a 2.8-fold reduction in brain uptake (1.7 ± 0.2 versus 0.61% ± 0.09) ,whereas [99mTc]-DHP-DG just showed 1.9-fold reduction in heart uptake (2.2 ± 0.05 towards 1.16±0.10) at 1 h post-injection. On the basis of our results, it seems that ECB-DG and DHP-DG analogues could be used as brain and heart imaging agent respectively. PMID:24250633

  3. Glacier topography and elevation changes derived from Pléiades sub-meter stereo images

    NASA Astrophysics Data System (ADS)

    Berthier, E.; Vincent, C.; Magnússon, E.; Gunnlaugsson, Á. Þ.; Pitte, P.; Le Meur, E.; Masiokas, M.; Ruiz, L.; Pálsson, F.; Belart, J. M. C.; Wagnon, P.

    2014-12-01

    In response to climate change, most glaciers are losing mass and hence contribute to sea-level rise. Repeated and accurate mapping of their surface topography is required to estimate their mass balance and to extrapolate/calibrate sparse field glaciological measurements. In this study we evaluate the potential of sub-meter stereo imagery from the recently launched Pléiades satellites to derive digital elevation models (DEMs) of glaciers and their elevation changes. Our five evaluation sites, where nearly simultaneous field measurements were collected, are located in Iceland, the European Alps, the central Andes, Nepal and Antarctica. For Iceland, the Pléiades DEM is also compared to a lidar DEM. The vertical biases of the Pléiades DEMs are less than 1 m if ground control points (GCPs) are used, but reach up to 7 m without GCPs. Even without GCPs, vertical biases can be reduced to a few decimetres by horizontal and vertical co-registration of the DEMs to reference altimetric data on ice-free terrain. Around these biases, the vertical precision of the Pléiades DEMs is ±1 m and even ±0.5 m on the flat glacier tongues (1? confidence level). Similar precision levels are obtained in the accumulation areas of glaciers and in Antarctica. We also demonstrate the high potential of Pléiades DEMs for measuring seasonal, annual and multi-annual elevation changes with an accuracy of 1 m or better if cloud-free images are available. The negative region-wide mass balances of glaciers in the Mont-Blanc area (-1.04 ± 0.23 m a-1 water equivalent, w.e.) are revealed by differencing Satellite pour l'Observation de la Terre 5 (SPOT 5) and Pléiades DEMs acquired in August 2003 and 2012, confirming the accelerated glacial wastage in the European Alps.

  4. Derivation of aurora scaling parameters from ground-based imaging observations: Numerical tests

    Microsoft Academic Search

    B. V. Kozelov; I. V. Golovchanskaya

    2010-01-01

    In the study of scaling properties of auroral luminosity variations by ground-based imaging observations, a problem arises that the actual scaling characteristics are distorted because of contributions to images from extension of auroral structures along the geomagnetic field. The field-aligned trends come into play for whatever small deviations from the magnetic zenith, making questionable the appropriateness of ground imaging data

  5. Modeling Stokes flow in real pore geometries derived by high resolution micro CT imaging

    NASA Astrophysics Data System (ADS)

    Halisch, M.; Müller, C.

    2012-04-01

    Meanwhile, numerical modeling of rock properties forms an important part of modern petrophysics. Substantially, equivalent rock models are used to describe and assess specific properties and phenomena, like fluid transport or complex electrical properties. In recent years, non-destructive computed X-ray tomography got more and more important - not only to take a quick and three dimensional look into rock samples but also to get access to in-situ sample information for highly accurate modeling purposes. Due to - by now - very high resolution of the 3D CT data sets (micron- to submicron range) also very small structures and sample features - e.g. micro porosity - can be visualized and used for numerical models of very high accuracy. Special demands even arise before numerical modeling can take place. Inappropriate filter applications (e.g. improper type of filter, wrong kernel, etc.) may lead to a significant corruption of spatial sample structure and / or even sample or void space volume. Because of these difficulties, especially small scale mineral- and pore space textures are very often lost and valuable in-situ information is erased. Segmentation of important sample features - porosity as well as rock matrix - based upon grayscale values strongly depends upon the scan quality and upon the experience of the application engineer, respectively. If the threshold for matrix-porosity separation is set too low, porosity can be quickly (and even more, due to restrictions of scanning resolution) underestimated. Contrary to this, a too high threshold over-determines porosity and small void space features as well as interfaces are changed and falsified. Image based phase separation in close combination with "conventional" analytics, as scanning electron microscopy or thin sectioning, greatly increase the reliability of this preliminary work. For segmentation and quantification purposes, a special CT imaging and processing software (Avizo Fire) has been used. By using this tool, 3D rock data can be assessed and interpreted by petrophysical means. Furthermore, pore structures can be directly segmented and hence could be used for so called image based modeling approach. The special XLabHydro module grants a finite volume solver for the direct assessment of Stokes flow (incompressible fluid, constant dynamic viscosity, stationary conditions and laminar flow) in real pore geometries. Nevertheless, also pore network extraction and numerical modeling with standard FE or lattice Boltzmann solvers is possible. By using the achieved voxel resolution as smallest node distance, fluid flow properties can be analyzed even in very small sample structures and hence with very high accuracy, especially with interaction to bigger parts of the pore network. The so derived results in combination with a direct 3D visualization within the structures offer great new insights and understanding in range of meso- and microscopic pore space phenomena.

  6. Improved High Resolution Controlled Enceladus Atlas derived from Cassini-ISS Images

    NASA Astrophysics Data System (ADS)

    Roatsch, T.; Kersten, E.; Hoffmeister, A.; Matz, K.-D.; Preusker, F.; Porco, C. C.

    2012-09-01

    The Cassini Imaging Science Subsystem (ISS) acquired 684 high-resolution images (< 1 km/pixel) of Enceladus during its tour through the Saturnian system since 2004. We have combined these images with lower-resolution Cassini images to produce a new high-resolution global controlled mosaic of this moonf Enceladus. This global mosaic is the baseline for the highresolution Enceladus atlas that consists of 15 tiles mapped at a scale of 1:500,000. The nomenclature used in this atlas was proposed by the Cassini imaging team and was approved by the International Astronomical Union (IAU). The whole atlas is available to the public through the Imaging Team's website [http://ciclops.org/maps].

  7. TART input manual

    SciTech Connect

    Kimlinger, J.R.; Plechaty, E.F.

    1982-04-01

    The TART code is a Monte Carlo neutron/photon transport code that is only on the CRAY computer. All the input cards for the TART code are listed, and definitions for all input parameters are given. The execution and limitations of the code are described, and input for two sample problems are given. (WHK)

  8. Surface bidirectional reflectance and albedo properties derived using a land cover-based approach with Moderate Resolution Imaging Spectroradiometer observations

    Microsoft Academic Search

    Yi Luo; Alexander P. Trishchenko; Rasim Latifovic; Zhanqing Li

    2005-01-01

    Surface bidirectional reflectance distribution function (BRDF) and albedo maps are derived from Moderate Resolution Imaging Spectroradiometer (MODIS) multiday surface reflectance composites with a 500-m spatial resolution (MODIS product MOD09A1\\/MYD09A1). The proposed method dubbed land cover-based fitting employs the processing of clear-sky reflectance data for similar land cover types and takes into account the magnitude of normalized difference vegetation index (NDVI).

  9. Surface bidirectional reflectance and albedo properties derived using a land cover–based approach with Moderate Resolution Imaging Spectroradiometer observations

    Microsoft Academic Search

    Yi Luo; Alexander P. Trishchenko; Rasim Latifovic; Zhanqing Li

    2005-01-01

    Surface bidirectional reflectance distribution function (BRDF) and albedo maps are derived from Moderate Resolution Imaging Spectroradiometer (MODIS) multiday surface reflectance composites with a 500-m spatial resolution (MODIS product MOD09A1\\/MYD09A1). The proposed method dubbed land cover–based fitting employs the processing of clear-sky reflectance data for similar land cover types and takes into account the magnitude of normalized difference vegetation index (NDVI).

  10. Mosaic Animations from Video Inputs

    Microsoft Academic Search

    Rafael Beserra Gomes; Tiago S. Souza; Bruno M. Carvalho

    2007-01-01

    Mosaic is a Non-Photorealistic Rendering (NPR) style for simulating the appearance of decorative tile mosaics. To simulate\\u000a realistic mosaics, a method must emphasize edges in the input image, while placing the tiles in an arrangement to minimize\\u000a the visible grout (the substrate used to glue the tiles that appears between them). This paper proposes a method for generating\\u000a mosaic animations

  11. High molecular weight chitosan derivative polymeric micelles encapsulating superparamagnetic iron oxide for tumor-targeted magnetic resonance imaging

    PubMed Central

    Xiao, Yunbin; Lin, Zuan Tao; Chen, Yanmei; Wang, He; Deng, Ya Li; Le, D Elizabeth; Bin, Jianguo; Li, Meiyu; Liao, Yulin; Liu, Yili; Jiang, Gangbiao; Bin, Jianping

    2015-01-01

    Magnetic resonance imaging (MRI) contrast agents based on chitosan derivatives have great potential for diagnosing diseases. However, stable tumor-targeted MRI contrast agents using micelles prepared from high molecular weight chitosan derivatives are seldom reported. In this study, we developed a novel tumor-targeted MRI vehicle via superparamagnetic iron oxide nanoparticles (SPIONs) encapsulated in self-aggregating polymeric folate-conjugated N-palmitoyl chitosan (FAPLCS) micelles. The tumor-targeting ability of FAPLCS/SPIONs was demonstrated in vitro and in vivo. The results of dynamic light scattering experiments showed that the micelles had a relatively narrow size distribution (136.60±3.90 nm) and excellent stability. FAPLCS/SPIONs showed low cytotoxicity and excellent biocompatibility in cellular toxicity tests. Both in vitro and in vivo studies demonstrated that FAPLCS/SPIONs bound specifically to folate receptor-positive HeLa cells, and that FAPLCS/SPIONs accumulated predominantly in established HeLa-derived tumors in mice. The signal intensities of T2-weighted images in established HeLa-derived tumors were reduced dramatically after intravenous micelle administration. Our study indicates that FAPLCS/SPION micelles can potentially serve as safe and effective MRI contrast agents for detecting tumors that overexpress folate receptors. PMID:25709439

  12. PET image reconstruction with system matrix based on point spread function derived from single photon incidence response

    E-print Network

    Xin, Fan; Ming-Kai, Yun; Xiao-Li, Sun; Xue-Xiang, Cao; Shuang-Quanm, Liu; Pei, Chai; Dao-Wu, Li; Long, Wei

    2014-01-01

    In positron emission tomography (PET) imaging, statistical iterative reconstruction (IR) techniques appear particularly promising since they can provide accurate physical model and geometric system description. The reconstructed image quality mainly depends on the system matrix model which describes the relationship between image space and projection space for the IR method. The system matrix can contain some physics factors of detection such as geometrical component and blurring component. Point spread function (PSF) is generally used to describe the blurring component. This paper proposes an IR method based on the PSF system matrix, which is derived from the single photon incidence response function. More specifically, the gamma photon incidence on a crystal array is simulated by the Monte Carlo (MC) simulation, and then the single photon incidence response functions are obtained. Subsequently, using the single photon incidence response functions, the coincidence blurring factor is acquired according to the...

  13. Image-derived, Three-dimensional Generative Models of Cellular Organization

    PubMed Central

    Peng, Tao; Murphy, Robert F.

    2011-01-01

    Given the importance of subcellular location to protein function, computational simulations of cell behaviors will ultimately require the ability to model the distributions of proteins within organelles and other structures. Towards this end, statistical learning methods have previously been used to build models of sets of two-dimensional microscope images, where each set contains multiple images for a single subcellular location pattern. The model learned from each set of images not only represents the pattern but also captures the variation in that pattern from cell to cell. The models consist of sub-models for nuclear shape, cell shape, organelle size and shape and organelle distribution relative to nuclear and cell boundaries, and allow synthesis of images with the expectation that they are drawn from the same underlying statistical distribution as the images used to train them. Here we extend this generative models approach to three dimensions using a similar framework, permitting protein subcellular locations to be described more accurately. Models of different patterns can be combined to yield synthetic multi-channel image containing as many proteins as desired, something that is difficult to obtain by direct microscope imaging for more than a few proteins. In addition, the model parameters represent a more compact and interpretable way of communicating subcellular patterns than descriptive image features, and may be particularly effective for automated identification of changes in subcellular organization caused by perturbagens. PMID:21472848

  14. In vivo imaging of zebrafish retinal cells using fluorescent coumarin derivatives

    Microsoft Academic Search

    Kohei Watanabe; Yuhei Nishimura; Takehiko Oka; Tsuyoshi Nomoto; Tetsuo Kon; Taichi Shintou; Minoru Hirano; Yasuhito Shimada; Noriko Umemoto; Junya Kuroyanagi; Zhipeng Wang; Zi Zhang; Norihiro Nishimura; Takeshi Miyazaki; Takeshi Imamura; Toshio Tanaka

    2010-01-01

    BACKGROUND: The zebrafish visual system is a good research model because the zebrafish retina is very similar to that of humans in terms of the morphologies and functions. Studies of the retina have been facilitated by improvements in imaging techniques. In vitro techniques such as immunohistochemistry and in vivo imaging using transgenic zebrafish have been proven useful for visualizing specific

  15. Classification of the images of gene expression patterns using neural networks based on multivalued neurons with the minimal number of inputs

    NASA Astrophysics Data System (ADS)

    Aizenberg, Igor N.; Butakoff, Constantine; Myasnikova, Ekaterina; Samsonova, Maria; Reinitz, John

    2002-04-01

    Multi-valued neurons (MVN) are the neural processing elements with complex-valued weights and high functionality. It is possible to implement an arbitrary mapping described by partial-defined multiple-valued function on the single MVN. The MVN-based neural networks are applied to temporal classification of images of gene expression patterns, obtained by confocal scanning microscopy. The classification results confirmed the efficiency of this method for image recognition. It was shown that frequency domain of the representation of gene expression images is highly effective for their description.

  16. Bilinearity in Spatiotemporal Integration of Synaptic Inputs

    PubMed Central

    Li, Songting; Liu, Nan; Zhang, Xiao-hui; Zhou, Douglas; Cai, David

    2014-01-01

    Neurons process information via integration of synaptic inputs from dendrites. Many experimental results demonstrate dendritic integration could be highly nonlinear, yet few theoretical analyses have been performed to obtain a precise quantitative characterization analytically. Based on asymptotic analysis of a two-compartment passive cable model, given a pair of time-dependent synaptic conductance inputs, we derive a bilinear spatiotemporal dendritic integration rule. The summed somatic potential can be well approximated by the linear summation of the two postsynaptic potentials elicited separately, plus a third additional bilinear term proportional to their product with a proportionality coefficient . The rule is valid for a pair of synaptic inputs of all types, including excitation-inhibition, excitation-excitation, and inhibition-inhibition. In addition, the rule is valid during the whole dendritic integration process for a pair of synaptic inputs with arbitrary input time differences and input locations. The coefficient is demonstrated to be nearly independent of the input strengths but is dependent on input times and input locations. This rule is then verified through simulation of a realistic pyramidal neuron model and in electrophysiological experiments of rat hippocampal CA1 neurons. The rule is further generalized to describe the spatiotemporal dendritic integration of multiple excitatory and inhibitory synaptic inputs. The integration of multiple inputs can be decomposed into the sum of all possible pairwise integration, where each paired integration obeys the bilinear rule. This decomposition leads to a graph representation of dendritic integration, which can be viewed as functionally sparse. PMID:25521832

  17. Color constancy using 3D scene geometry derived from a single image.

    PubMed

    Elfiky, Noha; Gevers, Theo; Gijsenij, Arjan; Gonzalez, Jordi

    2014-09-01

    The aim of color constancy is to remove the effect of the color of the light source. As color constancy is inherently an ill-posed problem, most of the existing color constancy algorithms are based on specific imaging assumptions (e.g., gray-world and white patch assumption). In this paper, 3D geometry models are used to determine which color constancy method to use for the different geometrical regions (depth/layer) found in images. The aim is to classify images into stages (rough 3D geometry models). According to stage models, images are divided into stage regions using hard and soft segmentation. After that, the best color constancy methods are selected for each geometry depth. To this end, we propose a method to combine color constancy algorithms by investigating the relation between depth, local image statistics, and color constancy. Image statistics are then exploited per depth to select the proper color constancy method. Our approach opens the possibility to estimate multiple illuminations by distinguishing nearby light source from distant illuminations. Experiments on state-of-the-art data sets show that the proposed algorithm outperforms state-of-the-art single color constancy algorithms with an improvement of almost 50% of median angular error. When using a perfect classifier (i.e, all of the test images are correctly classified into stages); the performance of the proposed method achieves an improvement of 52% of the median angular error compared with the best-performing single color constancy algorithm. PMID:25051548

  18. Three-dimensional image technology in forensic anthropology: Assessing the validity of biological profiles derived from CT-3D images of the skeleton

    NASA Astrophysics Data System (ADS)

    Garcia de Leon Valenzuela, Maria Julia

    This project explores the reliability of building a biological profile for an unknown individual based on three-dimensional (3D) images of the individual's skeleton. 3D imaging technology has been widely researched for medical and engineering applications, and it is increasingly being used as a tool for anthropological inquiry. While the question of whether a biological profile can be derived from 3D images of a skeleton with the same accuracy as achieved when using dry bones has been explored, bigger sample sizes, a standardized scanning protocol and more interobserver error data are needed before 3D methods can become widely and confidently used in forensic anthropology. 3D images of Computed Tomography (CT) scans were obtained from 130 innominate bones from Boston University's skeletal collection (School of Medicine). For each bone, both 3D images and original bones were assessed using the Phenice and Suchey-Brooks methods. Statistical analysis was used to determine the agreement between 3D image assessment versus traditional assessment. A pool of six individuals with varying experience in the field of forensic anthropology scored a subsample (n = 20) to explore interobserver error. While a high agreement was found for age and sex estimation for specimens scored by the author, the interobserver study shows that observers found it difficult to apply standard methods to 3D images. Higher levels of experience did not result in higher agreement between observers, as would be expected. Thus, a need for training in 3D visualization before applying anthropological methods to 3D bones is suggested. Future research should explore interobserver error using a larger sample size in order to test the hypothesis that training in 3D visualization will result in a higher agreement between scores. The need for the development of a standard scanning protocol focusing on the optimization of 3D image resolution is highlighted. Applications for this research include the possibility of digitizing skeletal collections in order to expand their use and for deriving skeletal collections from living populations and creating population-specific standards. Further research for the development of a standard scanning and processing protocol is needed before 3D methods in forensic anthropology are considered as reliable tools for generating biological profiles.

  19. Compensation for Spherical Geometric and Absorption Effects on Lower Thermospheric Emission Intensities Derived from High Earth Orbit Images

    NASA Technical Reports Server (NTRS)

    Swift, W.; Germany, G. A.; Richards, P. G.; Parks, G. K.; Brittnacher, M.; Spann, J. F., Jr.

    1997-01-01

    Remote sensing of the atmosphere from high earth orbit is very attractive due to the large field of view obtained and a true global perspective. This viewpoint is complicated by earth curvature effects so that slant path enhancement and absorption effects, small from low earth orbit, become dominant even at small nadir view angles. The effect is further complicated by the large range of local times and solar zenith angles in a single image leading to a modulation of the image intensity by a significant portion of the diurnal height variation of the absorbing layer. The latter effect is significant in particular for mesospheric, stratospheric and auroral emissions due to their depth in the atmosphere. As a particular case, the emissions from atomic oxygen (130.4 and 135.6 nm) and molecular nitrogen (two LBH bands, LBHS from 140 to 160 nm and LBHL from 160 to 180 nm) as viewed from the Ultraviolet Imager (UVI) are examined. The LBH emissions are of particular interest since LBHS has significant 02 absorption while LBHL does not, In the case of auroral emissions this differential absorption, well examined in the nadir, gives information about the height of the emission and therefore the energy of the precipitating particles. Using simulations of the viewing geometry and images from the UVI we examine these effects and obtain correction factors to adjust to the nadir case with a significant improvement of the derived characteristic energy. There is a surprisingly large effect on the images from the 02 diurnal layer height changes. An empirical compensation to the nadir case is explored based on the local nadir and local zenith angles for each portion of the image. These compensations are demonstrated as applied to the above emissions in both auroral and dayglow images and compared to models. The extension of these findings to other instruments, emissions and spectral regions is examined.

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

    NASA Astrophysics Data System (ADS)

    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.

  1. Ultraviolet Imaging Telescope images of the reflection nebula NGC 7023 - Derivation of ultraviolet scattering properties of dust grains

    NASA Technical Reports Server (NTRS)

    Witt, Adolf N.; Petersohn, Jens K.; Bohlin, Ralph C.; O'Connell, Robert W.; Roberts, Morton S.; Smith, Andrew M.; Stecher, Theodore P.

    1992-01-01

    The Ultraviolet Imaging Telescope as part of the Astro-1 mission, was used to obtain high-resolution surface brightness distribution data in six ultraviolet wavelength bands for the bright reflection nebula NGC 7023. From the quantitative comparison of the measured surface brightness gradients ratios of nebular to stellar flux, and detail radial surface brightness profiles with corresponding data from the visible, two major conclusions results: (1) the scattering in the near- and far-ultraviolet in this nebula is more strongly forward-directed than in the visible; (2) the dust albedo in the ultraviolet for wavelengths not less than 140 nm is identical to that in the visible, with the exception of the 220 nm bump in the extinction curve. In the wavelengths region of the bump, the albedo is reduced by 25 to 30 percent in comparison with wavelengths regions both shorter and longer. This lower albedo is expected, if the bump is a pure absorption feature.

  2. Design, synthesis, linear and nonlinear photophysical properties and biological imaging application of a novel ?-type pyrimidine-based thiophene derivative

    NASA Astrophysics Data System (ADS)

    Zhang, Qiong; Luo, Junshan; Ye, Lili; Wang, Hui; Huang, Bei; Zhang, Jun; Wu, Jieying; Zhang, Shengyi; Tian, Yupeng

    2014-09-01

    A novel D-?-A-?-D type thiophene pyrimidine derivative, 2,2?-thiophene-4, 6-bis (4-N,N-diethylbenzene ethenyl) pyrimidine (L), was designed, synthesized via Knoevenagel and Suzuki coupling reactions, and fully characterized. The results of X-ray diffraction analysis revealed that single crystal of L belongs to P212121 non-centrosymmetric space group, and the whole molecular skeleton exhibits a good coplanarity. Systematic photophysical properties were investigated for L. The connections between the properties and structure were explained relying on theoretical calculation. The thiophene pyrimidine derivative shows strong third-order nonlinear optical response and large two-photon absorption (2PA) cross section in high polar solvents. Finally, preliminary exploration in biological imaging also has been carried out, it shows a good biological application prospect.

  3. DERIVATION OF THE MAGNETIC FIELD IN A CORONAL MASS EJECTION CORE VIA MULTI-FREQUENCY RADIO IMAGING

    SciTech Connect

    Tun, Samuel D. [The Naval Research Laboratory, Washington, DC 20375 (United States)] [The Naval Research Laboratory, Washington, DC 20375 (United States); Vourlidas, A. [Space Science Division, Naval Research Laboratory, Washington, DC 20375 (United States)] [Space Science Division, Naval Research Laboratory, Washington, DC 20375 (United States)

    2013-04-01

    The magnetic field within the core of a coronal mass ejection (CME) on 2010 August 14 is derived from analysis of multi-wavelength radio imaging data. This CME's core was found to be the source of a moving type IV radio burst, whose emission is here determined to arise from the gyrosynchrotron process. The CME core's true trajectory, electron density, and line-of-sight depth are derived from stereoscopic observations, constraining these parameters in the radio emission models. We find that the CME carries a substantial amount of mildly relativistic electrons (E < 100 keV) in a strong magnetic field (B < 15 G), and that the spectra at lower heights are preferentially suppressed at lower frequencies through absorption from thermal electrons. We discuss the results in light of previous moving type IV burst studies, and outline a plan for the eventual use of radio methods for CME magnetic field diagnostics.

  4. EFM data mapped into 2D images of tip-sample contact potential difference and capacitance second derivative

    PubMed Central

    Lilliu, S.; Maragliano, C.; Hampton, M.; Elliott, M.; Stefancich, M.; Chiesa, M.; Dahlem, M. S.; Macdonald, J. E.

    2013-01-01

    We report a simple technique for mapping Electrostatic Force Microscopy (EFM) bias sweep data into 2D images. The method allows simultaneous probing, in the same scanning area, of the contact potential difference and the second derivative of the capacitance between tip and sample, along with the height information. The only required equipment consists of a microscope with lift-mode EFM capable of phase shift detection. We designate this approach as Scanning Probe Potential Electrostatic Force Microscopy (SPP-EFM). An open-source MATLAB Graphical User Interface (GUI) for images acquisition, processing and analysis has been developed. The technique is tested with Indium Tin Oxide (ITO) and with poly(3-hexylthiophene) (P3HT) nanowires for organic transistor applications. PMID:24284731

  5. Elastic nonlinear amplitude versus angle inversion and data-driven depth imaging in stratified media derived from inverse scattering approximations

    NASA Astrophysics Data System (ADS)

    Amundsen, Lasse; Reitan, Arne; Arntsen, Børge; Ursin, Bjørn

    2008-08-01

    This paper extends from acoustic to elastic the theory for nonlinear direct amplitude versus angle (AVA) inversion and data-driven depth imaging for a depth-variable medium published by the authors in this journal. The method which is derived by direct inversion of the forward model of elastic single compressional wave scattering requires no information of the velocities and density, except for the velocities and density of the uppermost layer which is the acoustic reference medium where the source and receiver are situated at finite distance above the elastic scattering medium. The vertically varying velocities and density of the scattering medium are estimated in a data-driven manner solely from the angle- and depth-dependent Born potential depth profile computed by constant-velocity imaging.

  6. EFM data mapped into 2D images of tip-sample contact potential difference and capacitance second derivative

    NASA Astrophysics Data System (ADS)

    Lilliu, S.; Maragliano, C.; Hampton, M.; Elliott, M.; Stefancich, M.; Chiesa, M.; Dahlem, M. S.; MacDonald, J. E.

    2013-11-01

    We report a simple technique for mapping Electrostatic Force Microscopy (EFM) bias sweep data into 2D images. The method allows simultaneous probing, in the same scanning area, of the contact potential difference and the second derivative of the capacitance between tip and sample, along with the height information. The only required equipment consists of a microscope with lift-mode EFM capable of phase shift detection. We designate this approach as Scanning Probe Potential Electrostatic Force Microscopy (SPP-EFM). An open-source MATLAB Graphical User Interface (GUI) for images acquisition, processing and analysis has been developed. The technique is tested with Indium Tin Oxide (ITO) and with poly(3-hexylthiophene) (P3HT) nanowires for organic transistor applications.

  7. (99m)Tc-labeled dibenzylideneacetone derivatives as potential SPECT probes for in vivo imaging of ?-amyloid plaque.

    PubMed

    Yang, Yanping; Cui, Mengchao; Jin, Bing; Wang, Xuedan; Li, Zijing; Yu, Pingrong; Jia, Jianhua; Fu, Hualong; Jia, Hongmei; Liu, Boli

    2013-06-01

    Four (99m)Tc-labeled dibenzylideneacetone derivatives and corresponding rhenium complexes were successfully synthesized and biologically evaluated as potential imaging probes for A? plaques using SPECT. All rhenium complexes (5a-d) showed affinity for A?(1-42) aggregates (Ki = 13.6-120.9 nM), and selectively stained the A? plaques on brain sections of transgenic mice. Biodistribution in normal mice revealed that [(99m)Tc]5a-d exhibited moderate initial uptake (0.31%-0.49% ID/g at 2 min) and reasonable brain washout at 60 min post-injection. Although additional optimizations are still needed to facilitate it's penetration through BBB, the present results indicate that [(99m)Tc]5a may be a potential SPECT probe for imaging A? plaques in Alzheimer's brains. PMID:23644192

  8. MDS MIC Catalog Inputs

    NASA Technical Reports Server (NTRS)

    Johnson-Throop, Kathy A.; Vowell, C. W.; Smith, Byron; Darcy, Jeannette

    2006-01-01

    This viewgraph presentation reviews the inputs to the MDS Medical Information Communique (MIC) catalog. The purpose of the group is to provide input for updating the MDS MIC Catalog and to request that MMOP assign Action Item to other working groups and FSs to support the MITWG Process for developing MIC-DDs.

  9. Derivation of new emission factors for quantification of mass emissions when using optical gas imaging for detecting leaks.

    PubMed

    Lev-On, Miriam; Epperson, David; Siegell, Jeffrey; Ritter, Karin

    2007-09-01

    This paper describes the development of new "leak/no-leak" emission factors that are suitable for estimating facilities' fugitive emissions when using an alternative work practice (AWP) that is based on optical gas imaging technology for detecting leaking piping system components. These emission factors were derived for valves, pumps, and connectors/flanges for instrument leak detection thresholds ranging from 3 to 60 g/hr using a combination of field data and Monte Carlo statistical simulation techniques. These newly derived leak/no-leak emission factors are designed to replace the U.S. Environment Protection Agency (EPA) 1995 Protocol factors, which were based on Method 21 monitoring of leaks at "uncontrolled" facilities. The emission factors published in the 1995 Protocol have not been updated since the 1970s. This derivation is based on results where the authors document the use of a Monte Carlo simulation technique to quantify the required leak detection thresholds that provide equal--or better--environmental benefits for an AWP. The use of these newly derived emission factors is demonstrated for different methods of computing fugitive emissions from a hypothetical model refinery. The resulting facility emissions calculated by using these new emission factors is compared with the existing emission estimation methods provided in the EPA 1995 Protocol. The results demonstrate that the new emission factors provide an emission estimate that is the closest to that obtained from the direct determination of total emissions by Monte Carlo simulations. PMID:17912925

  10. Time-lapse Imaging of Primary Preneoplastic Mammary Epithelial Cells Derived from Genetically Engineered Mouse Models of Breast Cancer

    PubMed Central

    Nakles, Rebecca E.; Millman, Sarah L.; Cabrera, M. Carla; Johnson, Peter; Mueller, Susette; Hoppe, Philipp S.; Schroeder, Timm; Furth, Priscilla A.

    2013-01-01

    Time-lapse imaging can be used to compare behavior of cultured primary preneoplastic mammary epithelial cells derived from different genetically engineered mouse models of breast cancer. For example, time between cell divisions (cell lifetimes), apoptotic cell numbers, evolution of morphological changes, and mechanism of colony formation can be quantified and compared in cells carrying specific genetic lesions. Primary mammary epithelial cell cultures are generated from mammary glands without palpable tumor. Glands are carefully resected with clear separation from adjacent muscle, lymph nodes are removed, and single-cell suspensions of enriched mammary epithelial cells are generated by mincing mammary tissue followed by enzymatic dissociation and filtration. Single-cell suspensions are plated and placed directly under a microscope within an incubator chamber for live-cell imaging. Sixteen 650 ?m x 700 ?m fields in a 4x4 configuration from each well of a 6-well plate are imaged every 15 min for 5 days. Time-lapse images are examined directly to measure cellular behaviors that can include mechanism and frequency of cell colony formation within the first 24 hr of plating the cells (aggregation versus cell proliferation), incidence of apoptosis, and phasing of morphological changes. Single-cell tracking is used to generate cell fate maps for measurement of individual cell lifetimes and investigation of cell division patterns. Quantitative data are statistically analyzed to assess for significant differences in behavior correlated with specific genetic lesions. PMID:23425702

  11. Reliability of MRI-derived cortical and subcortical morphometric measures: Effects of pulse sequence, voxel geometry, and parallel imaging

    PubMed Central

    Wonderlick, J.S.; Ziegler, D.A.; Hosseini-Varnamkhasti, P.; Locascio, J.J.; Bakkour, A.; van der Kouwe, A.; Triantafyllou, C.; Corkin, S.; Dickerson, B.C.

    2009-01-01

    Advances in magnetic resonance imaging (MRI) have contributed greatly to the study of neurodegenerative processes, psychiatric disorders, and normal human development, but the effect of such improvements on the reliability of downstream morphometric measures has not been extensively studied. We examined how MRI-derived neurostructural measures are affected by three technological advancements: parallel acceleration, increased spatial resolution, and the use of a high bandwidth multiecho sequence. Test-retest data were collected from 11 healthy participants during 2 imaging sessions occurring approximately 2 weeks apart. We acquired 4 T1-weighted MP-RAGE sequences during each session: a non-accelerated anisotropic sequence (MPR), a non-accelerated isotropic sequence (ISO), an accelerated isotropic sequence (ISH), and an accelerated isotropic high bandwidth multiecho sequence (MEM). Cortical thickness and volumetric measures were computed for each sequence to assess test-retest reliability and measurement bias. Reliability was extremely high for most measures and similar across imaging parameters. Significant measurement bias was observed, however, between MPR and all isotropic sequences for all cortical regions and some subcortical structures. These results suggest that these improvements in MRI acquisition technology do not compromise data reproducibility, but that consistency should be maintained in choosing imaging parameters for structural MRI studies. PMID:19038349

  12. Quantifying bedside-derived imaging of microcirculatory abnormalities in septic patients: a prospective validation study

    Microsoft Academic Search

    E Christiaan Boerma; Keshen R Mathura; Peter HJ van der Voort; Peter E Spronk; Can Ince

    2005-01-01

    INTRODUCTION: The introduction of orthogonal polarization spectral (OPS) imaging in clinical research has elucidated new perspectives on the role of microcirculatory flow abnormalities in the pathogenesis of sepsis. Essential to the process of understanding and reproducing these abnormalities is the method of quantification of flow scores. METHODS: In a consensus meeting with collaboraters from six research centres in different fields

  13. Radiolabeled mannosylated dextran derivatives bearing an NIR-fluorophore for sentinel lymph node imaging.

    PubMed

    Morais, Maurício; Campello, Maria P C; Xavier, Catarina; Heemskerk, Johannes; Correia, João D G; Lahoutte, Tony; Caveliers, Vicky; Hernot, Sophie; Santos, Isabel

    2014-11-19

    Current methods for sentinel lymph node (SLN) mapping involve the use of radioactivity detection with technetium-99m sulfur colloid and/or visually guided identification using a blue dye. To overcome the kinetic variations of two individual imaging agents through the lymphatic system, we report herein on two multifunctional macromolecules, 5a and 6a, that contain a radionuclide ((99m)Tc or (68)Ga) and a near-infrared (NIR) reporter for pre- and/or intraoperative SLN mapping by nuclear and NIR optical imaging techniques. Both bimodal probes are dextran-based polymers (10 kDa) functionalized with pyrazole-diamine (Pz) or 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) chelating units for labeling with fac-[(99m)Tc(CO)3](+) or (68)Ga(III), respectively, mannose units for receptor targeting, and NIR fluorophore units for optical imaging. The probes allowed a clear visualization of the popliteal node by single-photon emission computed tomography (SPECT/CT) or positron emission tomography (PET/CT), as well as real-time optically guided excision. Biodistribution studies confirmed that both macromolecules present a significant accumulation in the popliteal node (5a: 3.87 ± 0.63% IA/organ; 6a: 1.04 ± 0.26% IA/organ), with minimal spread to other organs. The multifunctional nanoplatforms display a popliteal extraction efficiency >90%, highlighting their potential to be further explored as dual imaging agents. PMID:25265437

  14. Water-soluble derivatives of chitosan as a target delivery system of 99m Tc to some organs in vivo for nuclear imaging and biodistribution

    Microsoft Academic Search

    Dalia L. Hawary; Mohamed A. Motaleb; Hamed Farag; Osiris W. Guirguis; Maher Z. Elsabee

    Carboxymethyl chitosan, (CMC), and N-lauryl-carboxymethyl chitosan (LCMC), have been prepared as water soluble derivatives of chitosan. These biodegradable chitosan\\u000a derivatives were characterized and investigated for nuclear imaging and body distribution. They were labeled with 99mTc to use them as targeted delivery to some organs in vivo for nuclear imaging and to follow their biodistribution within\\u000a the body. The factors controlling

  15. High Resolution Vesta Survey Atlas derived from Dawn-FC images

    NASA Astrophysics Data System (ADS)

    Roatsch, T.; Kersten, E.; Preusker, F.; Scholten, F.; Jaumann, R.; Coradini, A.; Nathues, A.; Raymond, C. A.; Russell, C. T.

    2011-12-01

    In August 2011, the Dawn Framing Camera will acquire hundreds of high-resolution images (about 250 m/pixel) during its Survey orbit around Vesta. We will combine these images to a global controlled ortho-rectified mosaic of Vesta. This global mosaic is the basis for the high-resolution Vesta Survey atlas that consists of 4 tiles (subdivision of the synoptic format) mapped at a scale of 1:1,500,000. The nomenclature used in this atlas will be based on names and places historically associated with the Roman goddess Vesta. The Dawn team will propose feature names compliant with the rules of the IAU. Selected examples of map sheets of the atlas will be shown in this presentation.

  16. Hyaluronic acid derivative-coated nanohybrid liposomes for cancer imaging and drug delivery.

    PubMed

    Park, Ju-Hwan; Cho, Hyun-Jong; Yoon, Hong Yeol; Yoon, In-Soo; Ko, Seung-Hak; Shim, Jae-Seong; Cho, Jee-Hyun; Park, Jae Hyung; Kim, Kwangmeyung; Kwon, Ick Chan; Kim, Dae-Duk

    2014-01-28

    Nanohybrid liposomes coated with amphiphilic hyaluronic acid-ceramide (HACE) was fabricated for targeted delivery of anticancer drug and in vivo cancer imaging. Nanohybrid liposomes including doxorubicin (DOX) and Magnevist, a contrast agent for magnetic resonance (MR) imaging, with 120-130nm mean diameter and a narrow size distribution were developed. DOX release from the developed formulation was improved at acidic pH (pH5.5 and 6.8) versus physiological pH (pH7.4). Cytotoxicity induced by the blank plain liposome was reduced by coating the outer surface of the nanohybrid liposome with HACE. Cellular uptake of DOX from the nanohybrid liposome was enhanced by HA and CD44 receptor interaction, versus the plain liposome. In vivo contrast-enhancing effects revealed that the nanohybrid liposome can be used as a tumor targeting MR imaging probe for cancer diagnosis. In a pharmacokinetic study in rats, in vivo clearance of DOX was decreased in the order DOX solution, plain liposome (F2), and nanohybrid liposome (F3), indicating prolonged circulation of the drug in the blood stream and improved therapeutic efficacy of the nanohybrid liposome (F3). Based on these findings, the nanohybrid liposomal system may be a useful candidate for real-time cancer diagnosis and therapy. PMID:24280260

  17. An Analysis of Whole Body Tracer Kinetics in Dynamic PET Studies With Application to Image-Based Blood Input Function Extraction

    PubMed Central

    Huang, Jian; O’Sullivan, Finbarr

    2014-01-01

    In a positron emission tomography (PET) study, the local uptake of the tracer is dependent on vascular delivery and retention. For dynamic studies the measured uptake time-course information can be best interpreted when knowledge of the time-course of tracer in the blood is available. This is certainly true for the most established tracers such as 18F-Fluorodeoxyglucose (FDG) and 15O-Water (H2O). Since direct sampling of blood as part of PET studies is increasingly impractical, there is ongoing interest in image-extraction of blood time-course information. But analysis of PET-measured blood pool signals is complicated because they will typically involve a combination of arterial, venous and tissue information. Thus, a careful appreciation of these components is needed to interpret the available data. To facilitate this process, we propose a novel Markov chain model for representation of the circulation of a tracer atom in the body. The model represents both arterial and venous time-course patterns. Under reasonable conditions equilibration of tracer activity in arterial and venous blood is achieved by the end of the PET study—consistent with empirical measurement. Statistical inference for Markov model parameters is a challenge. A penalized nonlinear least squares process, incorporating a generalized cross-validation score, is proposed. Random effects analysis is used to adaptively specify the structure of the penalty function based on historical samples of directly measured blood data. A collection of arterially sampled data from PET studies with FDG and H2O is used to illustrate the methodology. These data analyses are highly supportive of the overall modeling approach. An adaptation of the model to the problem of extraction of arterial blood signals from imaging data is also developed and promising preliminary results for cerebral and thoracic imaging studies with FDG and H2O are obtained. PMID:24770914

  18. Congestion control through input rate regulation

    Microsoft Academic Search

    Moshe Sidi; Wen-zu Liu; Israel Cidon; Inder Gopal

    1989-01-01

    Input-rate-regulation schemes are extensively studied from the viewpoint of smoothing and regulating effects of the incoming traffic. The smoothing effect is characterized by the variance of the interdeparture time of the packet-departure process from the input-rate-regulation mechanism. Under the assumption of Poisson arrivals, the characteristics of this departure process are explicitly derived in terms of the scheme's parameters, and the

  19. Input-Filter Design for Switching Regulators

    Microsoft Academic Search

    FREDC. LEE; Yuan Yu

    1979-01-01

    The interaction between the input filter and the control loop of switching regulators often results in detrimental effects, such as loop instability, transient response, and audio-signal-rejection rate, etc. A small-signal average model is derived to investigate these effects. Design constraints of an input-filter and switching-regulator system are formulated. An optimum low-pass and light-weight filter configuration is proposed.

  20. Input: A Communication Experience

    ERIC Educational Resources Information Center

    Westbrock, Leon

    1973-01-01

    Reports on Project Input at the Hoffman, Minnesota High School which gives students experience in using oral language with residents in a nursing home, retarded children and adults, and pupils in an elementary school. (RB)

  1. Format( )MEDIC( )Input

    NASA Astrophysics Data System (ADS)

    Foster, K.

    1994-09-01

    This document is a description of a computer program called Format( )MEDIC( )Input. The purpose of this program is to allow the user to quickly reformat wind velocity data in the Model Evaluation Database (MEDb) into a reasonable 'first cut' set of MEDIC input files (MEDIC.nml, StnLoc.Met, and Observ.Met). The user is cautioned that these resulting input files must be reviewed for correctness and completeness. This program will not format MEDb data into a Problem Station Library or Problem Metdata File. A description of how the program reformats the data is provided, along with a description of the required and optional user input and a description of the resulting output files. A description of the MEDb is not provided here but can be found in the RAS Division Model Evaluation Database Description document.

  2. Surface bidirectional reflectance and albedo properties derived using a land cover-based approach with Moderate Resolution Imaging Spectroradiometer observations

    NASA Astrophysics Data System (ADS)

    Luo, Yi; Trishchenko, Alexander P.; Latifovic, Rasim; Li, Zhanqing

    2005-01-01

    Surface bidirectional reflectance distribution function (BRDF) and albedo maps are derived from Moderate Resolution Imaging Spectroradiometer (MODIS) multiday surface reflectance composites with a 500-m spatial resolution (MODIS product MOD09A1/MYD09A1). The proposed method dubbed land cover-based fitting employs the processing of clear-sky reflectance data for similar land cover types and takes into account the magnitude of normalized difference vegetation index (NDVI). The BRDF is derived through the fitting of pixel data sorted into small bins according to the values of angular variables and NDVI. Robust statistical processing is applied to reduce the influence of noise and outliers. This method increases the success rate of the fitting process and enables more accurate monitoring of surface temporal changes during periods of rapid spring vegetation green up and autumn leaf fall, as well as changes due to agricultural practices and snow cover variations. The approach is specifically applied over the Atmospheric Radiation Measurement Program Southern Great Plains area. Results are compared to alternative BRDF/albedo products, such as the MOD43 albedo and Multiangle Imaging Spectroradiometer surface products that are derived through a pixel-based fitting process. A good agreement was generally found between different data sets. For example, the average biases in the visible and near-infrared bands are usually less than 0.01 and 0.02, respectively, and correlation coefficients are typically larger than 0.80. An analysis of these differences identifies some unique advantages of the proposed method, such as the ability to capture rapidly changing surface properties and an increased performance in the case of reduced number of clear-sky observations because of frequent cloudy conditions. Results suggest that the developed land cover-based methodology is valuable for the purpose of surface BRDF and albedo mapping using MODIS observations.

  3. Imaging studies of photodamage and recovery of anthraquinone derivatives doped into PMMA

    NASA Astrophysics Data System (ADS)

    Anderson, Benjamin; Ramini, Shiva K.; Kuzyk, Mark G.

    2011-12-01

    One of the efficiency-limiting factors of optical devices used at high intensities is photo damage to the optical materials. In devices that use organic dyes, photo damage causes irreversible damage to the chromophores, deteriorating efficiency, and eventually causes failure. Our present work focuses on monitoring degradation and recovery of anthraquinone dye doped PMMA thin films with a digital imaging apparatus, with the goal of understanding the mechanisms. Our results suggest the possibility of making optical components more resistant to photodamage, and capable of self recovery, removing the necessity to constantly replace components damaged by high intensity light.

  4. Synthesis of a Cu2+-Selective Probe Derived from Rhodamine and Its Application in Cell Imaging

    PubMed Central

    Yu, Chunwei; Wen, Yingying; Zhang, Jun

    2014-01-01

    A new fluorescent probe P based on rhodamine for Cu2+ was synthesized and characterized. The new probe P showed high selectivity to Cu2+ over other tested metal ions. With optimal conditions, the proposed probe P worked in a wide linear range of 1.0 × 10?6?1.0 × 10?5 M with a detection limit of 3.3 × 10?7 M Cu2+ in ethanol-water solution (9:1, v:v, 20 mM HEPES, pH 7.0). Furthermore, it has been used for imaging of Cu2+ in living cells with satisfying results. PMID:25397918

  5. Establishing the resting state default mode network derived from functional magnetic resonance imaging tasks as an endophenotype: A twins study.

    PubMed

    Korgaonkar, Mayuresh S; Ram, Kaushik; Williams, Leanne M; Gatt, Justine M; Grieve, Stuart M

    2014-08-01

    The resting state default mode network (DMN) has been shown to characterize a number of neurological and psychiatric disorders. Evidence suggests an underlying genetic basis for this network and hence could serve as potential endophenotype for these disorders. Heritability is a defining criterion for endophenotypes. The DMN is measured either using a resting-state functional magnetic resonance imaging (fMRI) scan or by extracting resting state activity from task-based fMRI. The current study is the first to evaluate heritability of this task-derived resting activity. 250 healthy adult twins (79 monozygotic and 46 dizygotic same sex twin pairs) completed five cognitive and emotion processing fMRI tasks. Resting state DMN functional connectivity was derived from these five fMRI tasks. We validated this approach by comparing connectivity estimates from task-derived resting activity for all five fMRI tasks, with those obtained using a dedicated task-free resting state scan in an independent cohort of 27 healthy individuals. Structural equation modeling using the classic twin design was used to estimate the genetic and environmental contributions to variance for the resting-state DMN functional connectivity. About 9-41% of the variance in functional connectivity between the DMN nodes was attributed to genetic contribution with the greatest heritability found for functional connectivity between the posterior cingulate and right inferior parietal nodes (P<0.001). Our data provide new evidence that functional connectivity measures from the intrinsic DMN derived from task-based fMRI datasets are under genetic control and have the potential to serve as endophenotypes for genetically predisposed psychiatric and neurological disorders. PMID:24453120

  6. Acoustic nonlinear amplitude versus angle inversion and data-driven depth imaging in stratified media derived from inverse scattering approximations

    NASA Astrophysics Data System (ADS)

    Amundsen, Lasse; Reitan, Arne; Arntsen, Børge; Ursin, Bjørn

    2006-12-01

    This paper presents a new theory for nonlinear direct amplitude versus angle (AVA) inversion and data-driven depth imaging for a depth-variable acoustic medium. The method which is derived by direct inversion of the forward model of acoustic single scattering requires no information of the velocity and density potentials (subsurface properties), except for the velocity and density of the uppermost layer which is the reference medium where the source and receiver are situated at a finite distance above the scattering medium. The vertically varying velocity and density of the scattering medium are estimated in a data-driven manner solely from the angle- and depth-dependent Born potential profile. The inversion method is obtained in three main steps. In step one, the Born potential profile is computed by constant-velocity imaging (migration) of the single scattering data in the time intercept-slowness domain. Generally, interfaces in the Born potential are severely mislocated in depth compared to the true potential. In step two, 'squeezed' depth-dependent velocity and density potentials are estimated by nonlinear direct AVA inversion of the Born potential after residual-moveout correction. Step three estimates the actual depth-dependent velocity and density potentials by stretching the squeezed potentials so that their interfaces are moved towards the correct depth. In the nomenclature of seismic processing, the three steps can be described by the sequence constant-velocity (partial) migration-inversion-residual migration. In contrast to conventional, velocity-dependent depth migration, which requires an accurate estimate of the velocities of the actual medium to obtain the proper image, the depth imaging in step three requires the squeezed actual velocity potential with interfaces matching those of the zero-angle Born potential depth profile. This is exactly the velocity potential that is found in step two.

  7. Nitrogen-doped carbon dots derived from polyvinyl pyrrolidone and their multicolor cell imaging

    NASA Astrophysics Data System (ADS)

    Ding, Hui; Zhang, Peng; Wang, Tian-Yi; Kong, Ji-Lie; Xiong, Huan-Ming

    2014-05-01

    Nitrogen-doped carbon dots (N-CDs) with a high quantum yield of 19.6% were prepared by calcining polyvinyl pyrrolidone (PVP, K-30), and then modified with 4,7,10-trioxa-1,13-tridecanediamine. The as-prepared N-CDs exhibited excitation-dependent and pH-sensitive photoluminescence. Transmission electron microscopy and Raman spectra demonstrated the graphitic structure of the N-CDs. Fourier transform infrared spectroscopy and x-ray diffraction studies revealed successful passivation and the presence of hydrophilic groups on the surface. Importantly, such modified quantum dots acted as good multicolor cell imaging probes due to their excellent fluorescent properties, low cytotoxicity and fine dispersity.

  8. Retrieval of Branching Sequences in an Associative Memory Model with Common External Input and Bias Input

    NASA Astrophysics Data System (ADS)

    Katahira, Kentaro; Kawamura, Masaki; Okanoya, Kazuo; Okada, Masato

    2007-04-01

    We investigate a recurrent neural network model with common external and bias inputs that can retrieve branching sequences. Retrieval of memory sequences is one of the most important functions of the brain. A lot of research has been done on neural networks that process memory sequences. Most of it has focused on fixed memory sequences. However, many animals can remember and recall branching sequences. Therefore, we propose an associative memory model that can retrieve branching sequences. Our model has bias input and common external input. Kawamura and Okada reported that common external input enables sequential memory retrieval in an associative memory model with auto- and weak cross-correlation connections. We show that retrieval processes along branching sequences are controllable with both the bias input and the common external input. To analyze the behaviors of our model, we derived the macroscopic dynamical description as a probability density function. The results obtained by our theory agree with those obtained by computer simulations.

  9. Deriving Atmospheric Properties and Escape Rates from MAVEN's Imaging UV Spectrograph (IUVS)

    NASA Astrophysics Data System (ADS)

    Schneider, Nicholas M.; IUVS Science Team

    2013-10-01

    MAVEN (Mars Volatile and Atmosphere EvolutioN) is a Mars Scout mission being readied for launch in November 2013. The key hardware and management partners are University of Colorado, Goddard Space Flight Center, University of California at Berkeley, Lockheed Martin, and the Jet Propulsion Laboratory. MAVEN carries a powerful suite of fields and particles instruments and a sophisticated remote sensing instrument, the Imaging UltraViolet Spectrograph (IUVS). This presentation begins by describing IUVS' science goals, instrument design, operational approach and data analysis strategy. IUVS supports the top-level MAVEN science goals: measure the present state of the atmosphere, observe its response to varying solar stimuli, and use the information to estimate loss from Mars' atmosphere over time. The instrument operates at low spectral resolution spanning the FUV and MUV ranges in separate channels, and at high resolution around the hydrogen Lyman alpha line to measure the D/H ratio in the upper atmosphere. MAVEN carries the instrument on an Articulated Payload Platform which orients the instrument for optimal observations during four segments of its 4.5 hr elliptical orbit. During periapse passage, IUVS uses a scan mirror to obtain vertical profiles of emissions from the atmosphere and ionosphere. Around apoapse, the instrument builds up low-resolution images of the atmosphere at multiple wavelengths. In between, the instrument measures emissions from oxygen, hydrogen and deuterium in the corona. IUVS also undertakes day-long stellar occultation campaigns at 2 month intervals, to measure the state of the atmosphere at altitudes below the airglow layer and in situ sampling. All data will be pipeline-processed from line brightnesses to column abundances, local densities and global 3-D maps. The focus of the presentation is development of these automatic processing algorithms and the data products they will provide to the Mars community through the PDS Atmospheres Node. The combined results from all instruments on ion and neutral escape will bear on the central question of the history of Mars' atmosphere and climate history. This work has been supported by NASA's MAVEN mission.

  10. Multimodality Molecular Imaging of [18F]-Fluorinated Carboplatin Derivative Encapsulated in [111In]-Labeled Liposomes

    NASA Astrophysics Data System (ADS)

    Lamichhane, Narottam

    Platinum based chemotherapy is amongst the mainstream DNA-damaging agents used in clinical cancer therapy today. Agents such as cisplatin, carboplatin are clinically prescribed for the treatment of solid tumors either as single agents, in combination, or as part of multi-modality treatment strategy. Despite the potent anti-tumor activity of these drugs, overall effectiveness is still hampered by inadequate delivery and retention of drug in tumor and unwanted normal tissue toxicity, induced by non-selective accumulation of drug in normal cells and tissues. Utilizing molecular imaging and nanoparticle technologies, this thesis aims to contribute to better understanding of how to improve the profile of platinum based therapy. By developing a novel fluorinated derivative of carboplatin, incorporating a Flourine-18 (18F) moiety as an inherent part of the molecule, quantitative measures of drug concentration in tumors and normal tissues can be directly determined in vivo and within the intact individual environment. A potential impact of this knowledge will be helpful in predicting the overall response of individual patients to the treatment. Specifically, the aim of this project, therefore, is the development of a fluorinated carboplatin drug derivative with an inherent positron emission tomography (PET) imaging capability, so that the accumulation of the drug in the tumor and normal organs can be studied during the course of therapy . A secondary objective of this research is to develop a proof of concept for simultaneous imaging of a PET radiolabeled drug with a SPECT radiolabeled liposomal formulation, enabling thereby bi-modal imaging of drug and delivery vehicle in vivo. The approach is challenging because it involves development in PET radiochemistry, PET and SPECT imaging, drug liposomal encapsulation, and a dual-modal imaging of radiolabeled drug and radiolabeled vehicle. The principal development is the synthesis of fluorinated carboplatin 19F-FCP using 2-(5-fluoro-pentyl)-2-methyl malonic acid as the labeling agent to coordinate with the cisplatin aqua complex. It was then used to treat various cell lines and compared with cisplatin and carboplatin at different concentrations ranging from 0.001 microM to 100 microM for 72 hrs and 96 hrs. IC50 values calculated from cell viability indicated that 19F-FCP is a more potent drug than Carboplatin. Manual radiosynthesis and characterization of [18F]-FCP was performed using [18F]-2-(5-fluoro-pentyl)-2-methyl malonic acid with coordination with cisplatin aqua complex. Automated radiosynthesis of [18F]-FCP was optimized using the manual synthetic procedures and using them as macros for the radiosynthesizer. [18F]-FCP was evaluated in vivo with detailed biodistribution studies and PET imaging in normal and KB 3-1 and KB 8-5 tumor xenograft bearing nude mice. The biodistribution studies and PET imaging of [18F]-FCP showed major uptake in kidneys which attributes to the renal clearance of radiotracer. In vivo plasma and urine stability demonstrated intact [18F]-FCP. [ 111In]-Labeled Liposomes was synthesized and physiochemical properties were assessed with DLS. [111In]-Labeled Liposome was evaluated in vivo with detailed pharmacokinetic studies and SPECT imaging. The biodistribution and ROI analysis from SPECT imaging showed the spleen and liver uptake of [111In]-Labeled Liposome and subsequent clearance of activity with time. [18F]-FCP encapsulated [111In]-Labeled Liposome was developed and physiochemical properties were characterized with DLS. [18F]-FCP encapsulated [111In]-Labeled Liposome was used for in vivo dual tracer PET and SPECT imaging from the same nanoconstruct in KB 3-1 (sensitive) and COLO 205 (resistant) tumor xenograft bearing nude mice. PET imaging of [18F]-FCP in KB 3-1 (sensitive) and COLO 205 (resistant) tumor xenograft bearing nude mice was performed. Naked [18F]-FCP and [18F]-FCP encapsulated [ 111In]-Labeled Liposome showed different pharmacokinetic profiles. PET imaging of [18F]-FCP showed major uptake in kidneys and bladder. However, [18F]-FCP encapsula

  11. Deriving two-dimensional ocean wave spectra and surface height maps from the Shuttel Imaging Radar (SIR-B)

    NASA Technical Reports Server (NTRS)

    Tilley, D. G.

    1986-01-01

    Directional ocean wave spectra were derived from Shuttle Imaging Radar (SIR-B) imagery in regions where nearly simultaneous aircraft-based measurements of the wave spectra were also available as part of the NASA Shuttle Mission 41G experiments. The SIR-B response to a coherently speckled scene is used to estimate the stationary system transfer function in the 15 even terms of an eighth-order two-dimensional polynomial. Surface elevation contours are assigned to SIR-B ocean scenes Fourier filtered using a empirical model of the modulation transfer function calibrated with independent measurements of wave height. The empirical measurements of the wave height distribution are illustrated for a variety of sea states.

  12. Integration of Image Data for Refining Building Boundaries Derived from Point Clouds

    NASA Astrophysics Data System (ADS)

    Perera, S. N.; Hetti Arachchige, N.; Schneider, D.

    2014-08-01

    Geometrically and topologically correct 3D building models are required to satisfy with new demands such as 3D cadastre, map updating, and decision making. More attention on building reconstruction has been paid using Airborne Laser Scanning (ALS) point cloud data. The planimetric accuracy of roof outlines, including step-edges is questionable in building models derived from only point clouds. This paper presents a new approach for the detection of accurate building boundaries by merging point clouds acquired by ALS and aerial photographs. It comprises two major parts: reconstruction of initial roof models from point clouds only, and refinement of their boundaries. A shortest closed circle (graph) analysis method is employed to generate building models in the first step. Having the advantages of high reliability, this method provides reconstruction without prior knowledge of primitive building types even when complex height jumps and various types of building roof are available. The accurate position of boundaries of the initial models is determined by the integration of the edges extracted from aerial photographs. In this process, scene constraints defined based on the initial roof models are introduced as the initial roof models are representing explicit unambiguous geometries about the scene. Experiments were conducted using the ISPRS benchmark test data. Based on test results, we show that the proposed approach can reconstruct 3D building models with higher geometrical (planimetry and vertical) and topological accuracy.

  13. Approach to derivation of SIR-C science requirements for calibration. [Shuttle Imaging Radar

    NASA Technical Reports Server (NTRS)

    Dubois, Pascale C.; Evans, Diane; Van Zyl, Jakob

    1992-01-01

    Many of the experiments proposed for the forthcoming SIR-C mission require calibrated data, for example those which emphasize (1) deriving quantitative geophysical information (e.g., surface roughness and dielectric constant), (2) monitoring daily and seasonal changes in the Earth's surface (e.g., soil moisture), (3) extending local case studies to regional and worldwide scales, and (4) using SIR-C data with other spaceborne sensors (e.g., ERS-1, JERS-1, and Radarsat). There are three different aspects to the SIR-C calibration problem: radiometric and geometric calibration, which have been previously reported, and polarimetric calibration. The study described in this paper is an attempt at determining the science requirements for polarimetric calibration for SIR-C. A model describing the effect of miscalibration is presented first, followed by an example describing how to assess the calibration requirements specific to an experiment. The effects of miscalibration on some commonly used polarimetric parameters are also discussed. It is shown that polarimetric calibration requirements are strongly application dependent. In consequence, the SIR-C investigators are advised to assess the calibration requirements of their own experiment. A set of numbers summarizing SIR-C polarimetric calibration goals concludes this paper.

  14. Diurnal, Seasonal, and Interannual Variations of Cloud Properties Derived for CERES From Imager Data

    NASA Technical Reports Server (NTRS)

    Minnis, Patrick; Young, David F.; Sun-Mack, Sunny; Trepte, Qing Z.; Chen, Yan; Brown, Richard R.; Gibson, Sharon; Heck, Patrick W.

    2004-01-01

    Simultaneous measurement of the radiation and cloud fields on a global basis is a key component in the effort to understand and model the interaction between clouds and radiation at the top of the atmosphere, at the surface, and within the atmosphere. The NASA Clouds and Earth s Radiant Energy System (CERES) Project, begun in 1998, is meeting this need. Broadband shortwave (SW) and longwave radiance measurements taken by the CERES scanners at resolutions between 10 and 20 km on the Tropical Rainfall Measuring Mission (TRMM), Terra, and Aqua satellites are matched to simultaneous retrievals of cloud height, phase, particle size, water path, and optical depth OD from the TRMM Visible Infrared Scanner (VIRS) and the Moderate Resolution Imaging Spectroradiometer (MODIS) on Terra and Aqua. Besides aiding the interpretation of the broadband radiances, the CERES cloud properties are valuable for understanding cloud variations at a variety of scales. In this paper, the resulting CERES cloud data taken to date are averaged at several temporal scales to examine the temporal and spatial variability of the cloud properties on a global scale at a 1 resolution.

  15. Emplacement of the 1907 Mauna Loa basalt flow as derived from precision topography and satellite imaging

    NASA Astrophysics Data System (ADS)

    Zimbelman, James R.; Garry, W. Brent; Johnston, Andrew K.; Williams, Steven H.

    2008-11-01

    An eruption in January of 1907, from the southwest rift zone of Mauna Loa, produced a substantial lava flow field. Satellite images and Differential Global Positioning System (DGPS) survey data, along with observations and photographs from the field, are combined to provide a new perspective on the 1907 eruption. Boundaries of the flow field from the satellite data, combined with field measurements of flow thickness, indicate an area of 25.1 km 2 and a volume of 86.6 million m 3. The eastern lobe of the flow field covers an area of 13.1 km 2, with a volume of 55.0 million m 3, and was emplaced with an average effusion rate of 119 m 3/s (at least, for the upper portion of the lobe). Ten DGPS topographic profiles across the eastern lobe aid in distinguishing the characteristics of, and transitions between, the zones identified during the emplacement of the 1984 Mauna Loa flow. Several subdivisions have been built directly on top of or adjacent to the 1907 lava flow. The strong likelihood of future eruptions from the Mauna Loa southwest rift zone makes these housing developments of particular importance for assessments of potential volcanic hazards.

  16. Two-photon fluorescent probe derived from naphthalimide for cysteine detection and imaging in living cells

    NASA Astrophysics Data System (ADS)

    Liu, Yanbin; Liu, Yuwen; Liu, Wei; Liang, Shucai

    2015-02-01

    A maleimide coupling naphthalimide was reported as new two-photon fluorescent (TPF) probe for cysteine (Cys). The probe was weakly fluorescent itself due to the donor-excited photoinduced electron transfer (d-PET). After reaction with Cys, d-PET process was blocked and fluorescence enhancement of the probe was observed at 470 nm. The d-PET principle was rationalized by theoretical calculations with density functional theory and time-dependent density functional theory. Thiol-maleimide addition between the probe and Cys was confirmed by 1H NMR and mass spectrum measurements. TPF analysis demonstrated a 24.7-fold emission increase of the probe induced by Cys upon excitation at 760 nm. The two-photon action cross-section of probe-Cys adduct at 760 nm reached 42 GM compared to 1.7 GM for free probe. The probe showed high sensitivity and selectivity to Cys over other potential interferences; especially it had the capability to discriminate Cys from glutathione and homocysteine. Through TPF imaging, the probe was successfully applied in the detection of Cys in living cells.

  17. Visualization of Membrane Rafts Using a Perylene Monoimide Derivative and Fluorescence Lifetime Imaging

    PubMed Central

    Margineanu, Anca; Hotta, Jun-ichi; Van der Auweraer, Mark; Ameloot, Marcel; Stefan, Alina; Beljonne, David; Engelborghs, Yves; Herrmann, Andreas; Müllen, Klaus; De Schryver, Frans C.; Hofkens, Johan

    2007-01-01

    A new membrane probe, based on the perylene imide chromophore, with excellent photophysical properties (high absorption coefficient, quantum yield (QY) ? 1, high photostability) and excited in the visible domain is proposed for the study of membrane rafts. Visualization of separation between the liquid-ordered (Lo) and the liquid-disordered (Ld) phases can be achieved in artificial membranes by fluorescence lifetime imaging due to the different decay times of the membrane probe in the two phases. Rafts on micrometer-scale in cell membranes due to cellular activation can also be observed by this method. The decay time of the dye in the Lo phase is higher than in organic solvents where its QY is 1. This allows proposing a (possible general) mechanism for the decay time increase in the Lo phase, based on the local field effects of the surrounding molecules. For other fluorophores with QY < 1, the suggested mechanism could also contribute, in addition to effects reducing the nonradiative decay pathways, to an increase of the fluorescence decay time in the Lo phase. PMID:17573424

  18. Two-photon fluorescent probe derived from naphthalimide for cysteine detection and imaging in living cells.

    PubMed

    Liu, Yanbin; Liu, Yuwen; Liu, Wei; Liang, Shucai

    2015-02-25

    A maleimide coupling naphthalimide was reported as new two-photon fluorescent (TPF) probe for cysteine (Cys). The probe was weakly fluorescent itself due to the donor-excited photoinduced electron transfer (d-PET). After reaction with Cys, d-PET process was blocked and fluorescence enhancement of the probe was observed at 470 nm. The d-PET principle was rationalized by theoretical calculations with density functional theory and time-dependent density functional theory. Thiol-maleimide addition between the probe and Cys was confirmed by (1)H NMR and mass spectrum measurements. TPF analysis demonstrated a 24.7-fold emission increase of the probe induced by Cys upon excitation at 760 nm. The two-photon action cross-section of probe-Cys adduct at 760 nm reached 42 GM compared to 1.7 GM for free probe. The probe showed high sensitivity and selectivity to Cys over other potential interferences; especially it had the capability to discriminate Cys from glutathione and homocysteine. Through TPF imaging, the probe was successfully applied in the detection of Cys in living cells. PMID:25240143

  19. Toxicological evaluation of a rotenone derivative in rodents for clinical myocardial perfusion imaging.

    PubMed

    Fernando, Pasan; Yan, Xuxu; Lockwood, Julia; Duan, Yin; Wei, Lihui; Glenn Wells, R; Bensimon, Corinne; Mullett, Wayne M; Ruddy, Terrence

    2014-06-01

    Myocardial perfusion scintigraphy is a valuable clinical tool for assessing coronary blood flow deficits in patients. We recently synthesized a new iodinated compound ((123)I-CMICE-013) based on rotenone and showed that it has excellent performance as a radiotracer for myocardial perfusion imaging. Here, we describe the cellular toxicity and subacute toxicity of CMICE-013 in rats. Cultured hepatocytes displayed sensitivity to rotenone but not CMICE-013 at equimolar concentrations. Following i.v. injection of CMICE-013 for 14 days, body weight, ambulation, behavior, grooming, guarding (abdominal, muscular), pale conjunctivae, and food intake were observed. Biochemical, hematological, and histopathological changes in tissues (heart, liver, kidney, spleen, lung, and brain) and echocardiography at pre- and post-dosing were also examined. All animals responded well to the daily injections of CMICE-013 and showed no mortality or adverse reactions with respect to the parameters above. Subacute i.v. injections at high- (5 ?g/kg) and low (1 ?g/kg)-dose levels did not result in any significant changes to either biochemical or hematological parameters and no detectable changes in histopathology compared to the vehicle or untreated animals. Echocardiographic analyses, including the measurements of cardiac function and anatomy (wall thickness, left atrial size, and left ventricular mass), were not different at pre- versus post-dose measures and were not different compared to the vehicle or untreated animals. Our observations in small animals reveal that CMICE-013 induces minimal toxicity when delivered intravenously for 14 days. PMID:24395712

  20. Vitamin B1 derived blue and green fluorescent carbon nanoparticles for cell-imaging application.

    PubMed

    Bhunia, Susanta Kumar; Pradhan, Nibedita; Jana, Nikhil R

    2014-05-28

    A carbon-based fluorescent nanoparticle is considered to be a new generation nontoxic nanoprobe suitable for various bioimaging and sensing applications. However, the synthesis of such a high-quality nanoparticle is challenging, and its application potential is mostly unexplored. Here we report a vitamin B1 carbonization-based approach for blue and green fluorescent carbon nanoparticles of <10 nm size with a fluorescence quantum of up to 76%. We found that carbonization of vitamin B1 in the presence of phosphate salt at ?90-130 °C for about 2 h produces highly fluorescent carbon nanoparticles of 1-6 nm size. The particle size and fluorescence property can be controlled by varying the reaction temperature and nature of phosphate salt. Elemental analysis shows the incorporation of a large percentage (up to 48 wt %) of other elements (such as nitrogen, oxygen, phophorus, and sulfur) in the carbon matrix. The chemical structure of vitamin B1 (thiamine) is unique in a sense that it consists of a large number of heteroatoms along with unsaturated bonds and offers low-temperature carbonization with the formation of a nanoparticle having an optimum ratio of sp(2) and sp(3) carbon atoms. These carbon nanoparticles have high colloidal stability and stable fluorescence and have been used as fluorescent imaging probes. PMID:24697797

  1. Input Decimated Ensembles

    NASA Technical Reports Server (NTRS)

    Tumer, Kagan; Oza, Nikunj C.; Clancy, Daniel (Technical Monitor)

    2001-01-01

    Using an ensemble of classifiers instead of a single classifier has been shown to improve generalization performance in many pattern recognition problems. However, the extent of such improvement depends greatly on the amount of correlation among the errors of the base classifiers. Therefore, reducing those correlations while keeping the classifiers' performance levels high is an important area of research. In this article, we explore input decimation (ID), a method which selects feature subsets for their ability to discriminate among the classes and uses them to decouple the base classifiers. We provide a summary of the theoretical benefits of correlation reduction, along with results of our method on two underwater sonar data sets, three benchmarks from the Probenl/UCI repositories, and two synthetic data sets. The results indicate that input decimated ensembles (IDEs) outperform ensembles whose base classifiers use all the input features; randomly selected subsets of features; and features created using principal components analysis, on a wide range of domains.

  2. Comparison of retinal thickness by Fourier-domain optical coherence tomography and OCT retinal image analysis software segmentation analysis derived from Stratus optical coherence tomography images

    PubMed Central

    Tátrai, Erika; Ranganathan, Sudarshan; Ferencz, Mária; DeBuc, Delia Cabrera; Somfai, Gábor Márk

    2011-01-01

    Purpose: To compare thickness measurements between Fourier-domain optical coherence tomography (FD-OCT) and time-domain OCT images analyzed with a custom-built OCT retinal image analysis software (OCTRIMA). Methods: Macular mapping (MM) by StratusOCT and MM5 and MM6 scanning protocols by an RTVue-100 FD-OCT device are performed on 11 subjects with no retinal pathology. Retinal thickness (RT) and the thickness of the ganglion cell complex (GCC) obtained with the MM6 protocol are compared for each early treatment diabetic retinopathy study (ETDRS)-like region with corresponding results obtained with OCTRIMA. RT results are compared by analysis of variance with Dunnett post hoc test, while GCC results are compared by paired t-test. Results: A high correlation is obtained for the RT between OCTRIMA and MM5 and MM6 protocols. In all regions, the StratusOCT provide the lowest RT values (mean difference 43 ± 8 ?m compared to OCTRIMA, and 42 ± 14 ?m compared to RTVue MM6). All RTVue GCC measurements were significantly thicker (mean difference between 6 and 12 ?m) than the GCC measurements of OCTRIMA. Conclusion: High correspondence of RT measurements is obtained not only for RT but also for the segmentation of intraretinal layers between FD-OCT and StratusOCT-derived OCTRIMA analysis. However, a correction factor is required to compensate for OCT-specific differences to make measurements more comparable to any available OCT device. PMID:21639572

  3. Comparison of retinal thickness by Fourier-domain optical coherence tomography and OCT retinal image analysis software segmentation analysis derived from Stratus optical coherence tomography images

    NASA Astrophysics Data System (ADS)

    Tátrai, Erika; Ranganathan, Sudarshan; Ferencz, Mária; Debuc, Delia Cabrera; Somfai, Gábor Márk

    2011-05-01

    Purpose: To compare thickness measurements between Fourier-domain optical coherence tomography (FD-OCT) and time-domain OCT images analyzed with a custom-built OCT retinal image analysis software (OCTRIMA). Methods: Macular mapping (MM) by StratusOCT and MM5 and MM6 scanning protocols by an RTVue-100 FD-OCT device are performed on 11 subjects with no retinal pathology. Retinal thickness (RT) and the thickness of the ganglion cell complex (GCC) obtained with the MM6 protocol are compared for each early treatment diabetic retinopathy study (ETDRS)-like region with corresponding results obtained with OCTRIMA. RT results are compared by analysis of variance with Dunnett post hoc test, while GCC results are compared by paired t-test. Results: A high correlation is obtained for the RT between OCTRIMA and MM5 and MM6 protocols. In all regions, the StratusOCT provide the lowest RT values (mean difference 43 +/- 8 ?m compared to OCTRIMA, and 42 +/- 14 ?m compared to RTVue MM6). All RTVue GCC measurements were significantly thicker (mean difference between 6 and 12 ?m) than the GCC measurements of OCTRIMA. Conclusion: High correspondence of RT measurements is obtained not only for RT but also for the segmentation of intraretinal layers between FD-OCT and StratusOCT-derived OCTRIMA analysis. However, a correction factor is required to compensate for OCT-specific differences to make measurements more comparable to any available OCT device.

  4. Biodistribution of mesenchymal stem cell-derived extracellular vesicles in a model of acute kidney injury monitored by optical imaging.

    PubMed

    Grange, Cristina; Tapparo, Marta; Bruno, Stefania; Chatterjee, Devasis; Quesenberry, Peter J; Tetta, Ciro; Camussi, Giovanni

    2014-05-01

    Mesenchymal stem cells (MSCs) contribute to the recovery of tissue injury, providing a paracrine support. Cell-derived extracellular vesicles (EVs), carrying membrane and cytoplasmatic constituents of the cell of origin, have been described as a fundamental mechanism of intercellular communication. We previously demonstrated that EVs derived from human MSCs accelerated recovery following acute kidney injury (AKI) in vivo. The aim of the present study was to investigate the biodistribution and the renal localization of EVs in AKI. For this purpose, two methods for EV labeling suitable for in vivo tracking with optical imaging (OI), were employed using near infrared (NIR) dye (DiD): i) labeled EVs were generated by MSCs pre-incubated with NIR dye and collected from cell supernatants; ii) purified EVs were directly labeled with NIR dye. EVs obtained with these two procedures were injected intravenously (i.v.) into mice with glycerol-induced AKI and into healthy mice to compare the efficacy of the two labeling methods for in vivo detection of EVs at the site of damage. We found that the labeled EVs accumulated specifically in the kidneys of the mice with AKI compared with the healthy controls. After 5 h, the EVs were detectable in whole body images and in dissected kidneys by OI with both types of labeling procedures. The directly labeled EVs showed a higher and brighter fluorescence compared with the labeled EVs produced by cells. The signal generated by the directly labeled EVs was maintained in time, but provided a higher background than that of the labeled EVs produced by cells. The comparison of the two methods indicated that the latter displayed a greater specificity for the injured kidney. PMID:24573178

  5. Algal Accessory Pigment Detection Using AVIRIS Image-Derived Spectral Radiance Data

    NASA Technical Reports Server (NTRS)

    Richardson, Laurie L.; Ambrosia, Vincent G.

    1996-01-01

    Visual and derivative analyses of AVIRIS spectral data can be used to detect algal accessory pigments in aquatic communities. This capability extends the use of remote sensing for the study of aquatic ecosystems by allowing detection of taxonomically significant pigment signatures which yield information about the type of algae present. Such information allows remote sensing-based assessment of aquatic ecosystem health, as in the detection of nuisance blooms of cyanobacteria or toxic blooms of dinoflagellates. Remote sensing of aquatic systems has traditionally focused on quantification of chlorophyll a, a photoreactive (and light-harvesting) pigment which is common to all algae as well as cyanobacteria (bluegreen algae). Due to the ubiquitousness of this pigment within algae, chl a is routinely measured to estimate algal biomass both during ground-truthing and using various airborne or satellite based sensors, including AVIRIS. Within the remote sensing and aquatic sciences communities, ongoing research has been performed to detect algal accessory pigments for assessment of algal population composition. This research is based on the fact that many algal accessory pigments are taxonomically significant, and all are spectrally unique. Aquatic scientists have been refining pigment analysis techniques, primarily high performance liquid chromatography, or HPLC, to detect specific pigments as a time-saving alternative to individual algal cell identifications and counts. Remote sensing scientists are investigating the use of pigment signatures to construct pigment libraries analogous to mineral spectral libraries used in geological remote sensing applications. The accessory pigment approach has been used successfully in remote sensing using data from the Thematic Mapper, low-altitude, multiple channel scanners, field spectroradiometers and the AVIRIS hyperspectral scanner. Due to spectral and spatial resolution capabilities, AVIRIS is the sensor of choice for such studies. We present here our results on detection of algal accessory pigments using AVIRIS data.

  6. Physical Conditions in the Central Parsec Derived from Mid-Infrared Imaging Photometry

    NASA Technical Reports Server (NTRS)

    Gezari, Dan; Dwek, Eli; Varosi, Frank

    2002-01-01

    Array camera images of the central 1 parsec of the Galactic Center at eight mid-infrared wavelengths between 4.8 and 20.0 microns with approximately 1 arcsec resolution are used to model the temperature, opacity and bolometric luminosity distributions of the emitting dust in the central parsec, and the extinction in the line of sight. We use the results to discriminate between two mechanisms for heating the dust: heating by radiation from a "central engine" (possibly a massive black hole associated with Sgr A*), or internal heating by luminous stars embedded in or among the dust clouds. The temperature and opacity distributions are consistent with the presence of self-luminous objects imbedded at prominent the IRS source positions. However, temperatures on the northern ann and east-west bar are highest along the inner flank of those structures surrounding the central cavity, while the dust opacity peaks further out from the central cavity. The warm inner ridge suggests heating by centrally located concentrated luminous sources, including IRS3 and IRS7. The of the model results are compared with the distributions of the various stellar populations in the central parsec. There is evidence for physical interaction between the warm emitting dust and luminous stars, including dozens of hot He1 emission line stars and B[] stars. The combined contributions of embedded stars at the IRS source positions and the luminous stars distributed throughout Sgr A West can account for the temperature enhancements and the luminosity distribution in the central parsec computed by the model.

  7. Derivation of lowland riparian wetland deposit architecture using geophysical image analysis and interface detection

    NASA Astrophysics Data System (ADS)

    Chambers, J. E.; Wilkinson, P. B.; Uhlemann, S.; Sorensen, J. P. R.; Roberts, C.; Newell, A. J.; Ward, W. O. C.; Binley, A.; Williams, P. J.; Gooddy, D. C.; Old, G.; Bai, L.

    2014-07-01

    For groundwater-surface water interactions to be understood in complex wetland settings, the architecture of the underlying deposits requires investigation at a spatial resolution sufficient to characterize significant hydraulic pathways. Discrete intrusive sampling using conventional approaches provides insufficient sample density and can be difficult to deploy on soft ground. Here a noninvasive geophysical imaging approach combining three-dimensional electrical resistivity tomography (ERT) and the novel application of gradient and isosurface-based edge detectors is considered as a means of illuminating wetland deposit architecture. The performance of three edge detectors were compared and evaluated against ground truth data, using a lowland riparian wetland demonstration site. Isosurface-based methods correlated well with intrusive data and were useful for defining the geometries of key geological interfaces (i.e., peat/gravels and gravels/Chalk). The use of gradient detectors approach was unsuccessful, indicating that the assumption that the steepest resistivity gradient coincides with the associated geological interface can be incorrect. These findings are relevant to the application of this approach in settings with a broadly layered geology with strata of contrasting resistivities. In addition, ERT revealed substantial structures in the gravels related to the depositional environment (i.e., braided fluvial system) and a complex distribution of low-permeability putty Chalk at the bedrock surface—with implications for preferential flow and variable exchange between river and groundwater systems. These results demonstrate that a combined approach using ERT and edge detectors can provide valuable information to support targeted monitoring and inform hydrological modeling of wetlands.

  8. PET image reconstruction with a system matrix containing point spread function derived from single photon incidence response

    NASA Astrophysics Data System (ADS)

    Fan, Xin; Wang, Hai-Peng; Yun, Ming-Kai; Sun, Xiao-Li; Cao, Xue-Xiang; Liu, Shuang-Quan; Chai, Pei; Li, Dao-Wu; Liu, Bao-Dong; Wang, Lu; Wei, Long

    2015-01-01

    A point spread function (PSF) for the blurring component in positron emission tomography (PET) is studied. The PSF matrix is derived from the single photon incidence response function. A statistical iterative reconstruction (IR) method based on the system matrix containing the PSF is developed. More specifically, the gamma photon incidence upon a crystal array is simulated by Monte Carlo (MC) simulation, and then the single photon incidence response functions are calculated. Subsequently, the single photon incidence response functions are used to compute the coincidence blurring factor according to the physical process of PET coincidence detection. Through weighting the ordinary system matrix response by the coincidence blurring factors, the IR system matrix containing the PSF is finally established. By using this system matrix, the image is reconstructed by an ordered subset expectation maximization (OSEM) algorithm. The experimental results show that the proposed system matrix can substantially improve the image radial resolution, contrast, and noise property. Furthermore, the simulated single gamma-ray incidence response function depends only on the crystal configuration, so the method could be extended to any PET scanner with the same detector crystal configuration. Project supported by the National Natural Science Foundation of China (Grant Nos. Y4811H805C and 81101175).

  9. Synthesis and Preliminary Evaluation of a 2-Oxoquinoline Carboxylic Acid Derivative for PET Imaging the Cannabinoid Type 2 Receptor

    PubMed Central

    Mu, Linjing; Slavik, Roger; Müller, Adrienne; Popaj, Kasim; ?ermak, Stjepko; Weber, Markus; Schibli, Roger; Krämer, Stefanie D.; Ametamey, Simon M.

    2014-01-01

    Cannabinoid receptor subtype 2 (CB2) has been shown to be up-regulated in activated microglia and therefore plays an important role in neuroinflammatory and neurodegenerative diseases such as multiple sclerosis, amyotrophic lateral sclerosis and Alzheimer’s disease. The CB2 receptor is therefore considered as a very promising target for therapeutic approaches as well as for imaging. A promising 2-oxoquinoline derivative designated KP23 was synthesized and radiolabeled and its potential as a ligand for PET imaging the CB2 receptor was evaluated. [11C]KP23 was obtained in 10%–25% radiochemical yield (decay corrected) and 99% radiochemical purity. It showed high stability in phosphate buffer, rat and mouse plasma. In vitro autoradiography of rat and mouse spleen slices, as spleen expresses a high physiological expression of CB2 receptors, demonstrated that [11C]KP23 exhibits specific binding towards CB2. High spleen uptake of [11C]KP23 was observed in dynamic in vivo PET studies with Wistar rats. In conclusion, [11C]KP23 showed promising in vitro and in vivo characteristics. Further evaluation with diseased animal model which has higher CB2 expression levels in the brain is warranted. PMID:24662272

  10. Dynamic optical imaging of metabolic and NADPH oxidase-derived superoxide in live mouse brain using fluorescence lifetime unmixing

    PubMed Central

    Hall, David J; Han, Sung-Ho; Chepetan, Andre; Inui, Edny G; Rogers, Mike; Dugan, Laura L

    2012-01-01

    Superoxide is the single-electron reduction product of molecular oxygen generated by mitochondria and the innate immune enzyme complex, nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (Nox), and its isoforms. Initially identified as critical to the host defense against infection, superoxide has recently emerged as an important signaling molecule and as a proposed mediator of central nervous system injury in stroke, neurodegenerative conditions, and aging itself. Complete understanding of superoxide in central nervous system disease has been hampered by lack of noninvasive imaging techniques to evaluate this highly reactive, short-lived molecule in vivo. Here we describe a novel optical imaging technique to monitor superoxide real time in intact animals using a fluorescent probe compound and fluorescence lifetime contrast-based unmixing. Specificity for superoxide was confirmed using validated mouse models with enhanced or attenuated brain superoxide production. Application of fluorescence lifetime unmixing removed autofluorescence, further enhanced sensitivity and specificity of the technique, permitted visualization of physiologically relevant levels of superoxide, and allowed superoxide in specific brain regions (e.g., hippocampus) to be mapped. Lifetime contrast-based unmixing permitted disease model-specific and brain region-specific differences in superoxide levels to be observed, suggesting this approach may provide valuable information on the role of mitochondrial and Nox-derived superoxide in both normal function and pathologic conditions in the central nervous system. PMID:21847136

  11. (18)F-AmBF3-MJ9: A novel radiofluorinated bombesin derivative for prostate cancer imaging.

    PubMed

    Pourghiasian, Maral; Liu, Zhibo; Pan, Jinhe; Zhang, Zhengxing; Colpo, Nadine; Lin, Kuo-Shyan; Perrin, David M; Bénard, François

    2015-04-01

    A novel radiofluorinated derivative of bombesin, (18)F-AmBF3-MJ9, was synthesized and evaluated for its potential to image prostate cancer by targeting the gastrin releasing peptide receptor (GRPR). AmBF3-MJ9 was prepared from an ammoniomethyl-trifluoroborate (AmBF3) conjugated alkyne 2 and azidoacetyl-MJ9 via a copper-catalyzed click reaction, and had good binding affinity for GRPR (Ki=0.5±0.1nM). The (18)F-labeling was performed via a facile one-step (18)F-(19)F isotope exchange reaction, and (18)F-AmBF3-MJ9 was obtained in 23±5% (n=3) radiochemical yield in 25min with >99% radiochemical purity and 100±32GBq/?mol specific activity. (18)F-AmBF3-MJ9 was stable in mouse plasma, and was partially (22-30%) internalized after binding to GRPR. Positron emission tomography (PET) imaging and biodistribution studies in mice showed fast renal excretion and good uptake of (18)F-AmBF3-MJ9 by GRPR-expressing pancreas and PC-3 prostate cancer xenografts. Tumor uptake was 1.37±0.25%ID/g at 1h, and 2.20±0.13%ID/g at 2h post-injection (p.i.) with low background uptake and excellent tumor visualization (tumor-to-muscle ratios of 75.4±5.5). These data suggest that (18)F-AmBF3-MJ9 is a promising PET tracer for imaging GRPR-expressing prostate cancers. PMID:25757604

  12. Handling Input and Output for COAMPS

    NASA Technical Reports Server (NTRS)

    Fitzpatrick, Patrick; Tran, Nam; Li, Yongzuo; Anantharaj, Valentine

    2007-01-01

    Two suites of software have been developed to handle the input and output of the Coupled Ocean Atmosphere Prediction System (COAMPS), which is a regional atmospheric model developed by the Navy for simulating and predicting weather. Typically, the initial and boundary conditions for COAMPS are provided by a flat-file representation of the Navy s global model. Additional algorithms are needed for running the COAMPS software using global models. One of the present suites satisfies this need for running COAMPS using the Global Forecast System (GFS) model of the National Oceanic and Atmospheric Administration. The first step in running COAMPS downloading of GFS data from an Internet file-transfer-protocol (FTP) server computer of the National Centers for Environmental Prediction (NCEP) is performed by one of the programs (SSC-00273) in this suite. The GFS data, which are in gridded binary (GRIB) format, are then changed to a COAMPS-compatible format by another program in the suite (SSC-00278). Once a forecast is complete, still another program in the suite (SSC-00274) sends the output data to a different server computer. The second suite of software (SSC- 00275) addresses the need to ingest up-to-date land-use-and-land-cover (LULC) data into COAMPS for use in specifying typical climatological values of such surface parameters as albedo, aerodynamic roughness, and ground wetness. This suite includes (1) a program to process LULC data derived from observations by the Moderate Resolution Imaging Spectroradiometer (MODIS) instruments aboard NASA s Terra and Aqua satellites, (2) programs to derive new climatological parameters for the 17-land-use-category MODIS data; and (3) a modified version of a FORTRAN subroutine to be used by COAMPS. The MODIS data files are processed to reformat them into a compressed American Standard Code for Information Interchange (ASCII) format used by COAMPS for efficient processing.

  13. MRI-Derived Restriction Spectrum Imaging Cellularity Index is Associated with High Grade Prostate Cancer on Radical Prostatectomy Specimens

    PubMed Central

    Liss, Michael A.; White, Nathan S.; Parsons, J. Kellogg; Schenker-Ahmed, Natalie M.; Rakow-Penner, Rebecca; Kuperman, Joshua M.; Bartsch, Hauke; Choi, Hyung W.; Mattrey, Robert F.; Bradley, William G.; Shabaik, Ahmed; Huang, Jiaoti; Margolis, Daniel J. A.; Raman, Steven S.; Marks, Leonard S.; Kane, Christopher J.; Reiter, Robert E.; Dale, Anders M.; Karow, David S.

    2015-01-01

    Purpose: We evaluate a novel magnetic resonance imaging (MRI) technique to improve detection of aggressive prostate cancer (PCa). Materials and Methods: We performed a retrospective analysis of pre-surgical prostate MRI scans using an advanced diffusion-weighted imaging technique called restriction spectrum imaging (RSI), which can be presented as a normalized z-score statistic. Scans were acquired prior to radical prostatectomy. Prostatectomy specimens were processed using whole-mount sectioning and regions of interest (ROIs) were drawn around individual PCa tumors. Corresponding ROIs were drawn on the MRI imaging and paired with ROIs in regions with no pathology. RSI z-score and conventional apparent diffusion coefficient (ADC) values were recorded for each ROI. Paired t-test, ANOVA, and logistic regression analyses were performed. Results: We evaluated 28 patients with 64 ROIs (28 benign and 36 PCa). The mean difference in RSI z-score (PCa ROI–Benign ROI) was 2.17 (SE?=?0.11; p?derived normalized cellularity index is associated with aggressive PCa as determined by pathologic Gleason scores. Further utilization of RSI techniques may serve to enhance standardized reporting systems for PCa in the future. PMID:25741473

  14. 983. Human Derived Dual Reporter\\/Suicide Gene System for Simultaneous Pet Imaging of Independent Molecular-Biological Processes In Vivo

    Microsoft Academic Search

    Vilia Tourkova; Malgorzata Dabrovska; Michael Doubrovin; Inna Serganova; Jelena Vider; Tatiana Beresten; Shangive Cai; Ronald Finn; Juri Gelovani Tjuvajev; Vladimir Ponomarev

    2004-01-01

    Objective. To develop a non-immunogenic human derived dual reporter gene system for simultaneous imaging of different molecular-genetic processes in humans using nuclear imaging techniques (PET) with potential suicide capabilities.Methods. Human mitochondrial thymidine kinase type 2 (hTK2) and human mitochondrial deoxyguanosine kinase (hdGK) cDNAs, truncated at the N-terminal, were expressed with green fluorescent protein (GFP) in U87 human glioma cell line

  15. Histogram-based fuzzy filter for image restoration

    Microsoft Academic Search

    Jung-hua Wang; Wen-jeng Liu; Lian-da Lin

    2002-01-01

    In this paper, we present a novel approach to the restora- tion of noise-corrupted image, which is particularly effective at removing highly impulsive noise while preserving image details. This is accomplished through a fuzzy smoothing filter constructed from a set of fuzzy member- ship functions for which the initial parameters are derived in accordance with input histogram. A principle of

  16. Horizontal and vertical distribution of bromine monoxide in northern Alaska during BROMEX derived from airborne imaging-DOAS measurements

    NASA Astrophysics Data System (ADS)

    Pöhler, Denis; Stephan, General; Zielcke, Johannes; Shepson, Paul B.; Sihler, Holger; Stirm, Brian H.; Frieß, Udo; Pratt, Kerry A.; Walsh, Steve; Simpson, William R.; Platt, Ulrich

    2013-04-01

    Bromine monoxide (BrO) is a reactive halogen species (RHS) and has been known for quite a while to have a profound impact on the chemistry of the polar tropospheric boundary layer. Details of the bromine release and reaction processes are still unclear, especially the role of frost flowers, first-year sea ice, aerosols, atmospheric stability and snow. To investigate important details of the bromine release, a novel imaging DOAS instrument for the ultraviolet wavelength range (300 to 400 nm) was deployed aboard a light twin-engine aircraft (ALAR, Purdue Univ.) as part of the BRomine, Ozone, and Mercury EXperiment (BROMEX) in Barrow, Alaska, in spring 2012. This instrument utilizes (1) a scanner system in nadir direction to map trace gas distributions of the overflown area at high spatial resolution and (2) a forward-looking system, to observe the vertical trace gas distribution. Both viewing directions are equipped with digital cameras, enabling the creation of aerial maps and the comparison of spectral data with background features. We derived horizontal and vertical distribution of bromine monoxide (BrO) and other gases (e.g. NO2) over a wide variety of sea, ice and land surface conditions (first-year sea ice, frost flowers, open leads, and arctic tundra). We observed strong horizontal gradients of BrO within few km and a fast movement of BrO plumes. Distributions change significantly within few hours. The data show interesting correlations to the different surfaces. Additionally a clear anti-correlation of BrO and NO2 can be observed. Tropospheric BrO-distributions derived from satellite observations match within the satellite resolution those seen with the aircraft. Vertical gradients show a shallow layer of BrO close to the surface. These and other results from the 11 flights will be presented together with conclusions of the involved chemistry.

  17. Atmospheric Motion Vectors Derived via a New Nested Tracking Algorithm Developed for the GOES-R Advanced Baseline Imager (ABI)

    NASA Astrophysics Data System (ADS)

    Daniels, J.; Bresky, W.; Wanzong, S.; Velden, C.

    2012-12-01

    A new Atmospheric Motion Vector (AMV) nested tracking algorithm has been developed for the Advanced Baseline Imager (ABI) to be flown on NOAA's future GOES-R satellite. The algorithm has been designed to capture the dominant motion in each target scene from a family of local motion vectors derived for each target scene. Capturing this dominant motion is achieved through use of a two-dimensional clustering algorithm that segregates local displacements into clusters. The dominant motion is taken to be the average of the local displacements of points belonging to the largest cluster. This approach prevents excessive averaging of motion that may be occurring at multiple levels or at different scales that can lead to a slow speed bias and a poor quality AMV. A representative height is assigned to the dominant motion vector through exclusive use of cloud heights from pixels belonging to the largest cluster. This algorithm has been demonstrated to significantly improve the slow speed bias typically observed in AMVs derived from satellite imagery. Meteosat SEVERI imagery is serving as an important GOES-R ABI proxy data source for the development, testing, and validation of the GOES-R AMV algorithms given its similarities (spectral coverage, pixel resolution, and scanning rate) and performance (spectral noise, navigation/registration) to the future GOES-R ABI. The new GOES-R AMV algorithm is also being applied to the instrumentation on the current operational GOES series of satellites and is expected to replace the heritage AMV algorithm being used in NESDIS operations today. Plans at NOAA/NESDIS also include using the new GOES-R AMV algorithm to generate AMVs from the future VIIRS instrument on the NPP satellite. Details of the GOES-R ABI AMV algorithm and the validation results will be presented and discussed.

  18. Deriving soil function maps to assess related ecosystem services using imaging spectroscopy in the Lyss agricultural area, Switzerland

    NASA Astrophysics Data System (ADS)

    Diek, Sanne; de Jong, Rogier; Braun, Daniela; Böhler, Jonas; Schaepman, Michael

    2014-05-01

    Soils play an important role in the benefits offered by ecosystems services. In densely populated Switzerland soils are a scarce resource, with high pressure on services ranging from urban expansion to over-utilization. Key change drivers include erosion, soil degradation, land management change and (chemical) pollution, which should be taken into consideration. Therefore there is an emerging need for an integrated, sustainable and efficient system assessing the management of soil and land as a resource. The use of remote sensing can offer spatio-temporal and quantitative information of extended areas. In particular imaging spectroscopy has shown to perfectly complement existing sampling schemes as secondary information for digital soil mapping. Although only the upper-most layer of soil interacts with light when using reflectance spectroscopy, it still can offer valuable information that can be utilized by farmers and decision makers. Fully processed airborne imaging spectrometer data from APEX as well as land cover classification for the agricultural area in Lyss were available. Based on several spectral analysis methods we derived multiple soil properties, including soil organic matter, soil texture, and mineralogy; complemented by vegetation parameters, including leaf area index, chlorophyll content, pigment distribution, and water content. The surface variables were retrieved using a combination of index-based and physically-based retrievals. Soil properties in partly to fully vegetated areas were interpolated using regression kriging based methods. This allowed the continuous assessment of potential soil functions as well as non-contiguous maps of abundances of combined soil and vegetation parameters. Based on a simple regression model we could make a rough estimate of ecosystem services. This provided the opportunity to look at the differences between the interpolated soil function maps and the non-contiguous (but combined) vegetation and soil function maps. We demonstrate the use of interpolated soil function maps as well as non-contiguous (but combined) vegetation and soil function maps and comment on their combined usability to assess related ecosystem services.

  19. Validation of plasmasphere electron density reconstructions derived from data on board CHAMP by IMAGE/RPI data

    NASA Astrophysics Data System (ADS)

    Gerzen, T.; Feltens, J.; Jakowski, N.; Galkin, I.; Denton, R.; Reinisch, B.; Zandbergen, R.

    2015-01-01

    Plasmaspheric electron content is, beyond the ionosphere as major source, a significant contributor to the overall TEC budget affecting GNSS signals. The plasmasphere can induce half or more of the GNSS range errors caused by atmospheric electrical charges, in particular at nighttime. At DLR Neustrelitz, Germany, GPS measurements recorded onboard the LEO satellite CHAMP were used to reconstruct the topside electron density distribution (ionosphere and plasmasphere) up to GPS altitude, applying a model-based assimilation technique. In this paper, the potential of these CHAMP topside reconstructions for analyzing space weather related changes in the geo-plasma is investigated. For this purpose, comparisons are made between the CHAMP reconstructed profiles and electron densities derived from passive radio wave observations by the IMAGE RPI instrument for years 2001 till 2005. The comparison results indicate that an improvement, compared to the electron density of a background model, can be achieved by CHAMP data assimilation. The improvement is especially visible in the L-shell region below 3, which contributes notably to the GNSS signal delays. However, for the region around the plasmapause, systematical electron density underestimations of the background model w.r.t. the IMAGE data are detected. The rather limited CHAMP data coverage and the degraded observation geometry at these high altitudes seem to be not sufficient for complete compensation of this underestimation during the assimilation procedure. The results presented in this paper demonstrate the strengths of LEO TEC data assimilation, but at the same time illustrate the necessity to improve the modeling of the plasmasphere region above 4 ER L-shell distances. Furthermore, they reveal the need of additional data to establish an appropriate data base for the modeling of the complete plasmasphere.

  20. A Tc-99m labeled laminin derived peptide, Tc-99m-YIGSR for thrombus specific imaging

    SciTech Connect

    Wang, G.J.; Oster, Z.H.; Som, P. [Brookhaven National Lab., Upton, NY (United States)] [and others

    1994-05-01

    Laminin derived adhesive peptides were studied as potential agents for thrombus specific imaging. Using a novel peptide Tc-99m labeling method studies were performed in vitro using human whole blood clots and platelets, and in vivo scintigraphy in animals with experimental thrombi. Aliquots of 0.1 ml human blood were placed in inclined Petri dishes until clot was well formed. Clots were rinsed 3x with phosphate buffer and 10 {mu}Ci Tc-99m YIGSR II was added. After incubation at room temperature for 1 hr, clots were again washed 3x. Residual activity was measured. Platelets were harvested using routine methods and incubated with Tc-99m YIGSR II, washed and assayed. Blocking experiments using cold YIGSR II showed that the Tc-99m labeled peptide preparation YIGSR II binds specifically and selectively to clot and platelets as compared to control experiments using nonspecific human Tc-99m IgG. Tissue distribution studies showed rapid blood clearance, urinary excretion and to a lesser degree GI tract excretion. Tc-99m YIGSR II was lower in all organs except kidneys compared to Tc-99m 50 H.19, Tc-99m IgG and Tc-99m YIGSR I. Tc-99m-YIGSR II consistently visualized thrombi within 30 min p.i. In vivo scintigraphic (thrombus/contralateral side) ratio was 3:1 and ex vivo direct counting (thrombosed to nonthrombosed vessel segment) was 5.4: 1. Compared to monoclonal antibodies peptide preparations are non- or minimally immunogenic, preparation is probably less expensive and there is also less danger of viral DNA contamination. These considerations and our data indicate that the Tc-99m-YIGSR II peptide has significant potential as a thrombus imaging agent.

  1. Extreme inputs/outputs for multiple input multiple output linear systems.

    SciTech Connect

    Smallwood, David Ora

    2005-09-01

    A linear structure is excited at multiple points with a stationary normal random process. The response of the structure is measured at multiple outputs. If the auto spectral densities of the inputs are specified, the phase relationships between the inputs are derived that will minimize or maximize the trace of the auto spectral density matrix of the outputs. If the autospectral densities of the outputs are specified, the phase relationships between the outputs that will minimize or maximize the trace of the input auto spectral density matrix are derived. It is shown that other phase relationships and ordinary coherence less than one will result in a trace intermediate between these extremes. Least favorable response and some classes of critical response are special cases of the development. It is shown that the derivation for stationary random waveforms can also be applied to nonstationary random, transients, and deterministic waveforms.

  2. Bioluminescent Imaging of Genetically Selected Induced Pluripotent Stem Cell-Derived Cardiomyocytes after Transplantation into Infarcted Heart of Syngeneic Recipients

    PubMed Central

    Lepperhof, Vera; Polchynski, Olga; Kruttwig, Klaus; Brüggemann, Chantal; Neef, Klaus; Drey, Florian; Zheng, Yunjie; Ackermann, Justus P.; Choi, Yeong-Hoon; Wunderlich, Thomas F.; Hoehn, Mathias; Hescheler, Jürgen; Šari?, Tomo

    2014-01-01

    Cell loss after transplantation is a major limitation for cell replacement approaches in regenerative medicine. To assess the survival kinetics of induced pluripotent stem cell (iPSC)-derived cardiomyocytes (CM) we generated transgenic murine iPSC lines which, in addition to CM-specific expression of puromycin N-acetyl-transferase and enhanced green fluorescent protein (EGFP), also constitutively express firefly luciferase (FLuc) for bioluminescence (BL) in vivo imaging. While undifferentiated iPSC lines generated by random integration of the transgene into the genome retained stable FLuc activity over many passages, the BL signal intensity was strongly decreased in purified iPS-CM compared to undifferentiated iPSC. Targeted integration of FLuc-expression cassette into the ROSA26 genomic locus using zinc finger nuclease (ZFN) technology strongly reduced transgene silencing in iPS-CM, leading to a several-fold higher BL compared to iPS-CM expressing FLuc from random genomic loci. To investigate the survival kinetics of iPS-CM in vivo, purified CM obtained from iPSC lines expressing FLuc from a random or the ROSA26 locus were transplanted into cryoinfarcted hearts of syngeneic mice. Engraftment of viable cells was monitored by BL imaging over 4 weeks. Transplanted iPS-CM were poorly retained in the myocardium independently of the cell line used. However, up to 8% of cells survived for 28 days at the site of injection, which was confirmed by immunohistological detection of EGFP-positive iPS-CM in the host tissue. Transplantation of iPS-CM did not affect the scar formation or capillary density in the periinfarct region of host myocardium. This report is the first to determine the survival kinetics of drug-selected iPS-CM in the infarcted heart using BL imaging and demonstrates that transgene silencing in the course of iPSC differentiation can be greatly reduced by employing genome editing technology. FLuc-expressing iPS-CM generated in this study will enable further studies to reduce their loss, increase long-term survival and functional integration upon transplantation. PMID:25226590

  3. Comparison of pressure-derived fractional flow reserve with poststenotic coronary flow velocity reserve for prediction of stress myocardial perfusion imaging results

    Microsoft Academic Search

    Christophe Tron; Thomas J. Donohue; Richard G. Bach; Frank V. Aguirre; Eugene A. Caracciolo; Thomas L. Wolford; D. Douglas Miller; Morton J. Kern

    1995-01-01

    The physiologic importance of coronary stenoses can be assessed indirectly by stress myocardial perfusion imaging or directly by translesional pressure and flow measurements. The aims of this study were to compare myocardial fractional flow reserve (FFRmyo), a recently proposed index of lesion significance derived from hyperemic translesional pressure gradients, with directly measured poststenotic flow velocity reserve for the prediction of

  4. Using Concept Maps to Assess the Effect of Graphing Calculators Use on Students' Concept Images of the Derivative at a Point

    ERIC Educational Resources Information Center

    Serhan, Derar

    2009-01-01

    This study used concept maps to investigate the effect of using graphing calculators on students' understanding of the derivative at a point. The study looked for differences between the concept images that are held by students' who are using graphing calculators and the students who are not using them. Seventy one students enrolled in two…

  5. In vivo imaging of adipose-derived mesenchymal stem cells in female nude mice after simulated childbirth injury

    PubMed Central

    DAI, MIAO; XU, PEIRONG; HOU, MIN; TENG, YINCHENG; WU, QINGKAI

    2015-01-01

    The aim of the present study was to track in vivo the distribution and survival of adipose-derived mesenchymal stem cells (ASCs) transplanted into female BALB/c nude mice following simulated childbirth injury, using green fluorescent protein and luciferase dual labeling, bioluminescent imaging (BLI) and histological evaluation. The results demonstrated that the dually labeled ASCs could be detected for up to eight weeks in vivo. The number of implanted cells decreased during the first three weeks, and then stabilized until the end of the experiment. According to the linear regression plot, ~27,621 implanted cells survived until eight weeks after implantation. Transplanted ASCs predominantly existed at the inoculation site of the vagina, with little or no spread to other organs. Histological analysis confirmed the survival of the engrafted ASCs. The study provided basic evidence that BLI techniques can be used to monitor ASCs in vivo in real time and in the long term. Through local administration, ASCs could survive in the long term to facilitate repair following pelvic-floor injury. PMID:25574200

  6. Teaching Image Formation by Extended Light Sources: The Use of a Model Derived from the History of Science

    NASA Astrophysics Data System (ADS)

    Dedes, Christos; Ravanis, Konstantinos

    2009-01-01

    This research, carried out in Greece on pupils aged 12-16, focuses on the transformation of their representations concerning light emission and image formation by extended light sources. The instructive process was carried out in two stages, each one having a different, distinct target set. During the first stage, the appropriate conflict conditions were created by contrasting the subjects’ predictions with the results of experimental situations inspired by the History of Science, with a view to destabilizing the pupils’ alternative representations. During the second stage, the experimental teaching intervention was carried out; it was based on the geometrical optics model and its parameters were derived from Kepler’s relevant historic experiment. For the duration of this process and within the framework of didactical interactions, an effort was made to reorganize initial limited representations and restructure them at the level of the accepted scientific model. The effectiveness of the intervention was evaluated two weeks later, using experimental tasks which had the same cognitive yet different empirical content with respect to the tasks conducted during the intervention. The results of the study showed that the majority of the subjects accepted the model of geometrical optics, that is, the pupils were able to correctly predict and adequately justify the experimental results based on the principle of punctiform light emission. Educational and research implications are discussed.

  7. Identification of a Novel Indoline Derivative for in Vivo Fluorescent Imaging of Blood-Brain Barrier Disruption in Animal Models

    PubMed Central

    2013-01-01

    Disruption of the blood-brain barrier (BBB) can occur in various pathophysiological conditions. Administration of extraneous tracers that can pass the disrupted, but not the intact, BBB and detection of the extravasation have been widely used to assess BBB disruption in animal models. Although several fluorescent tracers have been successfully used, the administration of these tracers basically requires intravascular injection, which can be laborious when using small animals such as zebrafish. To identify fluorescent tracers that could be easily administered into various animal models and visualize the BBB disruption in vivo, we prepared nine structurally related indoline derivatives (IDs) as a minimum set of diverse fluorescent compounds. We found that one ID, ZMB741, had the highest affinity for serum albumin and emitted the strongest fluorescence in the presence of serum albumin of the nine IDs tested. The affinity to serum albumin and the fluorescence intensity was superior to those of Evans blue and indocyanine green that have been conventionally used to assess the BBB disruption. We showed that ZMB741 could be administered into zebrafish by static immersion or mice by intraperitoneal injection and visualizes the active disruption of their BBB. These results suggest that ZMB741 can be a convenient and versatile tool for in vivo fluorescent imaging of BBB disruption in various animal models. The strategy used in this study can also be applied to diversity-oriented libraries to identify novel fluorescent tracers that may be superior to ZMB741. PMID:23668665

  8. Acquiring 3D Full-body Motion from Noisy and Ambiguous Input

    E-print Network

    Lou, Hui

    2012-07-16

    for yoga tree motion: (top left) Kinect results superimposed on input color images; (bottom left) our results superimposed on input depth data; (top right) observed 3D depth edges in yellow and rendered 3D depth edges from our results; (bottom right) our... from camera view superimposed on input color images; (top right) results without edge for yoga triangle motion (camera view and a second view), with results from camera view superimposed on input color images; (bottom right) results with edge...

  9. Fig.1: Brain image: (a) 4x SENSE reconstruction; (b) noise reduction in [1] using a T2 weighted reference image; (c) using the wavelet-derived reference image. (d) unaccelerated image.

    E-print Network

    . Robson3 , C. A. McKenzie4 , and D. K. Sodickson2 1 Biomedical Engineering, Columbia University, New York acquired reference image. We propose a method that can adaptively generate a reference image directly from. Method In Cartesian SENSE image reconstructions, unaliased pixels can be represented by a complex vector

  10. EU-FP7-iMars: Analysis of Mars Multi-Resolution Images using Auto-Coregistration, Data Mining and Crowd Source Techniques: an overview and a request for scientific inputs.

    NASA Astrophysics Data System (ADS)

    Muller, Jan-Peter; Gwinner, Klaus; van Gasselt, Stephan; Ivanov, Anton; Morley, Jeremy; Houghton, Robert; Bamford, Steven; Yershov, Vladimir; Sidirpoulos, Panagiotis; Kim, Jungrack

    2014-05-01

    Understanding the role of different planetary surface formation processes within our Solar System is one of the fundamental goals of planetary science research. There has been a revolution in planetary surface observations over the last 7 years, especially in 3D imaging of surface shape (down to resolutions of 10cm) and subsequent terrain correction of imagery from orbiting spacecraft. This has led to the ability to be able to overlay different epochs back to the mid-1970s, examine time-varying changes (such as the recent discovery of boulder movement [Orloff et al., 2011] or the sublimation of sub-surface ice revealed by meteoritic impact [Byrne et al., 2009] as well as examine geophysical phenomena, such as surface roughness on different length scales. Consequently we are seeing a dramatic improvement in our understanding of surface formation processes. Since January 2004 the ESA Mars Express has been acquiring global data, especially HRSC stereo (12.5-25m nadir images) with 87% coverage with images ?25m and more than 65% useful for stereo mapping (e.g. atmosphere sufficiently clear). It has been demonstrated [Gwinner et al., 2010] that HRSC has the highest possible planimetric accuracy of ?25m and is well co-registered with MOLA, which represents the global 3D reference frame. HRSC 3D and terrain-corrected image products therefore represent the best available 3D reference data for Mars. NASA began imaging the surface of Mars, initially from flybys in the 1960s with the first orbiter with images ?100m in the late 1970s from Viking Orbiter. The most recent orbiter to begin imaging in November 2006 is the NASA MRO which has acquired surface imagery of around 1% of the Martian surface from HiRISE (at ?20cm) and ?5% from CTX (?6m) in stereo. Unfortunately, for most of these NASA images, especially MGS, MO, VO and HiRISE their accuracy of georeferencing is often worse than the quality of Mars reference data from HRSC. This reduces their value for analysing changes in time series. Within the iMars project (http://i-Mars.eu), a fully automated large-scale processing ('Big Data') solution is being developed to generate the best possible multi-resolution DTM of Mars co-registered to HRSC (50-100m grid) products generated at DLR from CTX (6-20m grid, loc.cit.) and HiRISE (1-3m grids) on a large-scale linux cluster based at MSSL with 224 cores and 0.25 Pb of storage. The HRSC products are employed to provide a geographic reference for all current, future and historical NASA products using automated co-registration based on feature points and initial results will be shown. The metadata already available for all orbital imagery acquired to date, with poor georeferencing information, has been employed to determine the 'sweet spots' which have long time series of measurements with different spatial resolution ranges over the last ?50 years of observations and these will be shown. In 2015, as much of the entire NASA and ESA record of orbital images will be co-registered and the updated georeferencing information employed to generate a time series of terrain relief corrected orthorectified images (ORIs) back to 1977. Web-GIS using OGC protocols will be employed to allow exploration visually of changes of the surface. Data mining processing chains are being developed to search for changes in the Martian surface from 1971-2015 and the output of this data mining will be compared against the results from citizen scientists' measurements in a specialised Zooniverse implementation. Final co-registered data sets will be distributed through both European and US channels in a manner to be decided towards the end of the project. The resultant co-registered image datasets will represent the best possible capture of changes and evolutions in the Martian surface. A workshop is planned to be held during the EGU time period to try to capture scientific input on the relative priorities of different types of changes based on these 'sweet spots'. Acknowledgements: The research leading to these results has received funding from the European

  11. Modeling Recognition Memory Using the Similarity Structure of Natural Input

    Microsoft Academic Search

    Joyca P. W. Lacroix; Jaap M. J. Murre; Eric O. Postma; H. Jaap Van Den Herik

    2006-01-01

    Abstract The Natural Input Memory,(NIM) model is a new model for recognition memory,that operates on natural visual input. A biologically-informed perceptual pre-processing method,takes local samples (eye fixations) from a natural image and translates t hese into a feature-vector representation. During recognition, the model compares incoming pre-processed natural input to stored representations. By complementing,the recognition memory,process with a perceptual front-end, the

  12. Arctic science input wanted

    NASA Astrophysics Data System (ADS)

    The Arctic Research and Policy Act (Eos, June 26, 1984, p. 412) was signed into law by President Ronald Reagan this past July. One of its objectives is to develop a 5-year research plan for the Arctic. A request for input to this plan is being issued this week to nearly 500 people in science, engineering, and industry.To promote Arctic research and to recommend research policy in the Arctic, the new law establishes a five-member Arctic Research Commission, to be appointed by the President, and establishes an Interagency Arctic Research Policy Committee, to be composed of representatives from nearly a dozen agencies having interests in the region. The commission will make policy recommendations, and the interagency committee will implement those recommendations. The National Science Foundation (NSF) has been designated as the lead agency of the interagency committee.

  13. GWT.Input.1.9 05/16/2006 DATA INPUT INSTRUCTIONS FOR GROUND-WATER

    E-print Network

    GWT.Input.1.9 05/16/2006 DATA INPUT INSTRUCTIONS FOR GROUND-WATER TRANSPORT PROCESS (GWT) Version the Ground-Water Transport Process (GWT). It is derived directly from the MOC3D model (Konikow and others solute transport in conjunction with a simulation of ground-water flow using MODFLOW. The transport name

  14. Images

    Cancer.gov

    Home News and Events Multimedia Library Images Images:  Cancer Biology Image: Cell with DNA 72 DPI | 300 DPIDrawing depicting DNA molecule unwinding from a chromosome inside the nucleus of a cell. NHGRI >> View All Cancer Pathology/Imaging Image: Female

  15. Spatiotemporal variations of snowmelt in Antarctica derived from satellite scanning multichannel microwave radiometer and Special Sensor Microwave Imager data (1978-2004)

    Microsoft Academic Search

    Hongxing Liu; Lei Wang; Kenneth C. Jezek

    2006-01-01

    We derived the extent, onset date, end date, and duration of snowmelt in Antarctica from 1978 to 2004 using satellite passive microwave scanning multichannel microwave radiometer (SMMR) and Special Sensor Microwave Imager (SSM\\/I) data. A wavelet-transform-based method was developed to determine and characterize melt occurrences. About 9-12% of the Antarctic surface experiences melt annually. This is more than twice the

  16. Spatiotemporal variations of snowmelt in Antarctica derived from satellite scanning multichannel microwave radiometer and Special Sensor Microwave Imager data (1978–2004)

    Microsoft Academic Search

    Hongxing Liu; Lei Wang; Kenneth C. Jezek

    2006-01-01

    We derived the extent, onset date, end date, and duration of snowmelt in Antarctica from 1978 to 2004 using satellite passive microwave scanning multichannel microwave radiometer (SMMR) and Special Sensor Microwave Imager (SSM\\/I) data. A wavelet-transform-based method was developed to determine and characterize melt occurrences. About 9–12% of the Antarctic surface experiences melt annually. This is more than twice the

  17. Erythrocyte-derived photo-theranostic agents: hybrid nano-vesicles containing indocyanine green for near infrared imaging and therapeutic applications

    PubMed Central

    Bahmani, Baharak; Bacon, Danielle; Anvari, Bahman

    2013-01-01

    Development of theranostic nano-constructs may enable diagnosis and treatment of diseases at high spatial resolution. Some key requirements for clinical translation of such constructs are that they must be non-toxic, non-immunogenic, biodegradable, with extended circulating lifetime. Cell-based structures, particularly those derived from erythrocytes, are promising candidate carrier systems to satisfy these requirements. One particular type of theranostic materials utilize light-sensitive agents that once photo-activated can provide diagnostic imaging capability, and elicit therapeutic effects. Here we demonstrate the first successful engineering of hybrid nano-scale constructs derived from membranes of hemoglobin-depleted erythrocytes that encapsulate the near infrared chromophore, indocyanine green. We show the utility of the constructs as photo-theranostic agents in fluorescence imaging and photothermal destruction of human cells. These erythrocyte-mimicking nano-structures can be derived autologously, and may have broad applications in personal nanomedicine ranging from imaging and photo-destruction of cancerous tissues to vascular abnormalities, and longitudinal evaluations of therapeutic interventions. PMID:23846447

  18. Erythrocyte-derived photo-theranostic agents: hybrid nano-vesicles containing indocyanine green for near infrared imaging and therapeutic applications.

    PubMed

    Bahmani, Baharak; Bacon, Danielle; Anvari, Bahman

    2013-01-01

    Development of theranostic nano-constructs may enable diagnosis and treatment of diseases at high spatial resolution. Some key requirements for clinical translation of such constructs are that they must be non-toxic, non-immunogenic, biodegradable, with extended circulating lifetime. Cell-based structures, particularly those derived from erythrocytes, are promising candidate carrier systems to satisfy these requirements. One particular type of theranostic materials utilize light-sensitive agents that once photo-activated can provide diagnostic imaging capability, and elicit therapeutic effects. Here we demonstrate the first successful engineering of hybrid nano-scale constructs derived from membranes of hemoglobin-depleted erythrocytes that encapsulate the near infrared chromophore, indocyanine green. We show the utility of the constructs as photo-theranostic agents in fluorescence imaging and photothermal destruction of human cells. These erythrocyte-mimicking nano-structures can be derived autologously, and may have broad applications in personal nanomedicine ranging from imaging and photo-destruction of cancerous tissues to vascular abnormalities, and longitudinal evaluations of therapeutic interventions. PMID:23846447

  19. Erythrocyte-derived photo-theranostic agents: hybrid nano-vesicles containing indocyanine green for near infrared imaging and therapeutic applications

    NASA Astrophysics Data System (ADS)

    Bahmani, Baharak; Bacon, Danielle; Anvari, Bahman

    2013-07-01

    Development of theranostic nano-constructs may enable diagnosis and treatment of diseases at high spatial resolution. Some key requirements for clinical translation of such constructs are that they must be non-toxic, non-immunogenic, biodegradable, with extended circulating lifetime. Cell-based structures, particularly those derived from erythrocytes, are promising candidate carrier systems to satisfy these requirements. One particular type of theranostic materials utilize light-sensitive agents that once photo-activated can provide diagnostic imaging capability, and elicit therapeutic effects. Here we demonstrate the first successful engineering of hybrid nano-scale constructs derived from membranes of hemoglobin-depleted erythrocytes that encapsulate the near infrared chromophore, indocyanine green. We show the utility of the constructs as photo-theranostic agents in fluorescence imaging and photothermal destruction of human cells. These erythrocyte-mimicking nano-structures can be derived autologously, and may have broad applications in personal nanomedicine ranging from imaging and photo-destruction of cancerous tissues to vascular abnormalities, and longitudinal evaluations of therapeutic interventions.

  20. The value of satellite-derived snow cover images for calibrating a hydrological model in snow-dominated catchments in Central Asia

    NASA Astrophysics Data System (ADS)

    Duethmann, Doris; Peters, Juliane; Blume, Theresa; Vorogushyn, Sergiy; Güntner, Andreas

    2014-03-01

    Including satellite-derived snow cover data for hydrologic model calibration can be a good way to improve model internal consistency. This study applied a multiobjective genetic algorithm to characterize the trade-off curve between model performance in terms of discharge and snow cover area (SCA). Using a Monte Carlo-based approach, we further investigated the additional information content of an increasing number of SCA scenes used in the calibration period. The study was performed in six snowmelt-dominated headwater catchments of the Karadarya Basin in Kyrgyzstan, Central Asia, using the hydrological model WASA and snow cover data from four melt seasons retrieved from AVHRR (Advanced Very High Resolution Radiometer). We generally found only small trade-offs between good simulations with respect to discharge and SCA, but good model performance with respect to discharge did not exclude low performance in terms of SCA. On average, the snow cover error in the validation period could be reduced by very few images in the calibration period. Increasing the number of images resulted in only small further improvements. However, using only a small number of images involves the risk that these particular images cause the selection of parameter sets which are not representative for the catchment. It is therefore advisable to use a larger number of images. In this study, it was necessary to include at least 10-16 images.

  1. Linear Regression in High Dimension and/or for Correlated Inputs

    NASA Astrophysics Data System (ADS)

    Jacques, J.; Fraix-Burnet, D.

    2014-01-01

    Ordinary least square is the common way to estimate linear regression models. When inputs are correlated or when they are too numerous, regression methods using derived inputs directions or shrinkage methods can be efficient alternatives. Methods using derived inputs directions build new uncorrelated variables as linear combination of the initial inputs, whereas shrinkage methods introduce regularization and variable selection by penalizing the usual least square criterion. Both kinds of methods are presented and illustrated thanks to the R software on an astronomical dataset.

  2. SDR input power estimation algorithms

    NASA Astrophysics Data System (ADS)

    Briones, J. C.; Nappier, J. M.

    The General Dynamics (GD) S-Band software defined radio (SDR) in the Space Communications and Navigation (SCAN) Testbed on the International Space Station (ISS) provides experimenters an opportunity to develop and demonstrate experimental waveforms in space. The SDR has an analog and a digital automatic gain control (AGC) and the response of the AGCs to changes in SDR input power and temperature was characterized prior to the launch and installation of the SCAN Testbed on the ISS. The AGCs were used to estimate the SDR input power and SNR of the received signal and the characterization results showed a nonlinear response to SDR input power and temperature. In order to estimate the SDR input from the AGCs, three algorithms were developed and implemented on the ground software of the SCAN Testbed. The algorithms include a linear straight line estimator, which used the digital AGC and the temperature to estimate the SDR input power over a narrower section of the SDR input power range. There is a linear adaptive filter algorithm that uses both AGCs and the temperature to estimate the SDR input power over a wide input power range. Finally, an algorithm that uses neural networks was designed to estimate the input power over a wide range. This paper describes the algorithms in detail and their associated performance in estimating the SDR input power.

  3. Digital ortho-images — a powerful tool for the extraction of spatial- and geo-information

    Microsoft Academic Search

    Emmanuel P. Baltsavias

    1996-01-01

    Digital ortho-images provide great advantages in comparison to their analogue counterparts, especially with respect to flexibility, production of derived products and combination with other data sets. Today, production of digital ortho-images has become more commonplace due to the development of more powerful computers with sufficient resources, easier acquisition of input data, increased generation of digital data, development of many commercial

  4. Serial Input Output

    SciTech Connect

    Waite, Anthony; /SLAC

    2011-09-07

    Serial Input/Output (SIO) is designed to be a long term storage format of a sophistication somewhere between simple ASCII files and the techniques provided by inter alia Objectivity and Root. The former tend to be low density, information lossy (floating point numbers lose precision) and inflexible. The latter require abstract descriptions of the data with all that that implies in terms of extra complexity. The basic building blocks of SIO are streams, records and blocks. Streams provide the connections between the program and files. The user can define an arbitrary list of streams as required. A given stream must be opened for either reading or writing. SIO does not support read/write streams. If a stream is closed during the execution of a program, it can be reopened in either read or write mode to the same or a different file. Records represent a coherent grouping of data. Records consist of a collection of blocks (see next paragraph). The user can define a variety of records (headers, events, error logs, etc.) and request that any of them be written to any stream. When SIO reads a file, it first decodes the record name and if that record has been defined and unpacking has been requested for it, SIO proceeds to unpack the blocks. Blocks are user provided objects which do the real work of reading/writing the data. The user is responsible for writing the code for these blocks and for identifying these blocks to SIO at run time. To write a collection of blocks, the user must first connect them to a record. The record can then be written to a stream as described above. Note that the same block can be connected to many different records. When SIO reads a record, it scans through the blocks written and calls the corresponding block object (if it has been defined) to decode it. Undefined blocks are skipped. Each of these categories (streams, records and blocks) have some characteristics in common. Every stream, record and block has a name with the condition that each stream, record or block name must be unique in its category (i.e. all streams must have different names, but a stream can have the same name as a record). Each category is an arbitrary length list which is handled by a 'manager' and there is one manager for each category.

  5. Learning to represent visual input

    PubMed Central

    Hinton, Geoffrey E.

    2010-01-01

    One of the central problems in computational neuroscience is to understand how the object-recognition pathway of the cortex learns a deep hierarchy of nonlinear feature detectors. Recent progress in machine learning shows that it is possible to learn deep hierarchies without requiring any labelled data. The feature detectors are learned one layer at a time and the goal of the learning procedure is to form a good generative model of images, not to predict the class of each image. The learning procedure only requires the pairwise correlations between the activations of neuron-like processing units in adjacent layers. The original version of the learning procedure is derived from a quadratic ‘energy’ function but it can be extended to allow third-order, multiplicative interactions in which neurons gate the pairwise interactions between other neurons. A technique for factoring the third-order interactions leads to a learning module that again has a simple learning rule based on pairwise correlations. This module looks remarkably like modules that have been proposed by both biologists trying to explain the responses of neurons and engineers trying to create systems that can recognize objects. PMID:20008395

  6. Validation of GOES-9 Satellite-Derived Cloud Properties over the Tropical Western Pacific Region

    NASA Technical Reports Server (NTRS)

    Khaiyer, Mandana M.; Nordeen, Michele L.; Doeling, David R.; Chakrapani, Venkatasan; Minnis, Patrick; Smith, William L., Jr.

    2004-01-01

    Real-time processing of hourly GOES-9 images in the ARM TWP region began operationally in October 2003 and is continuing. The ARM sites provide an excellent source for validating this new satellitederived cloud and radiation property dataset. Derived cloud amounts, heights, and broadband shortwave fluxes are compared with similar quantities derived from ground-based instrumentation. The results will provide guidance for estimating uncertainties in the GOES-9 products and to develop improvements in the retrieval methodologies and input.

  7. Image Calibration

    NASA Technical Reports Server (NTRS)

    Peay, Christopher S.; Palacios, David M.

    2011-01-01

    Calibrate_Image calibrates images obtained from focal plane arrays so that the output image more accurately represents the observed scene. The function takes as input a degraded image along with a flat field image and a dark frame image produced by the focal plane array and outputs a corrected image. The three most prominent sources of image degradation are corrected for: dark current accumulation, gain non-uniformity across the focal plane array, and hot and/or dead pixels in the array. In the corrected output image the dark current is subtracted, the gain variation is equalized, and values for hot and dead pixels are estimated, using bicubic interpolation techniques.

  8. Opportunities to Refine Regional Crop Modeling Using Current and Simulated Future NASA Data Inputs in RPC Framework

    NASA Astrophysics Data System (ADS)

    Mali, P.; O'Hara, C. G.; Shrestha, B.; Sinclair, T.; Toll, D.

    2006-12-01

    The Sinclair soybean prediction model requires daily meteorological data inputs of minimum and maximum temperature, solar radiation, precipitation along with data such as planting date and day length based on latitude. The model estimates daily LAI (Leaf Area Index) from the input variables to simulate yield. The Sinclair model has been used operationally by USDA/FAS PECAD to provide soybean yield forecasts before harvest. Various approaches to deriving model input parameters from remote sensing datasets have been suggested to improve model efficiency and to reduce the time and labor requirements for regional yield predictions. This research will evaluate the use of current and simulated future NASA data sources as well as model products as proxy input parameters for regional yield predication. The effort will employ NASA data streams to determine whether the current NASA datasets from MODIS (Moderate Resolution Imaging Spectroradiometer) and simulated future products from VIIRS (Visible Infrared Imager / Radiometer Suite) as well as meteorological data from NASA `LDAS' (Land Data Assimilation System) can be used as surrogate input variables to replace the current method of data input in the model so as to improve the technical methodologies of regional yield prediction using remote sensing data streams. The area of interest is in Argentina, South America, one of the largest soybean growing nations. MODIS datasets and simulated VIIRS datasets from MODIS will be compared to rapidly prototype soybean production estimation and to benchmark the ability of NASA data-streams to provide vegetation vigor as an input to the soybean prediction model to provide effective technological solutions in an RPC framework for USDA/FAS PECAD's operational efficiency.

  9. Input detection by the discrete linear cascade model

    NASA Astrophysics Data System (ADS)

    Szöll?si-Nagy, A.

    1987-01-01

    This paper discusses inverse hydrological forecasting. As opposed to output prediction from known inputs (and model parameters), the detection of inputs from known outputs (and model parameters) is considered. The model used is the recursive, deterministic, discrete linear cascade model (DLCM) derived from the one-dimensional continuous two-parameter Kalinin-Milyukov-Nash (KMN) cascade set up in linear space. Input detection requires determination of the unsteady initial conditions. This is done via observability analysis. It is shown that the DLCM is observable and the unsteady initial states of the n-dimensional DLCM are uniquely computed from the first n discrete input/output data pairs, the inverse of the observability matrix and the first n DLCM impulse-response ordinates. The initial state vector is used in the recursive deterministic input-detection algorithm. The first n detected input values are necessarily identical with the first n actual inputs. A case study is presented, using the input-detection algorithm to derive operational rules for flood-release basins.

  10. Synthesis of superparamagnetic iron oxide nanoparticles coated with a DDNP-carboxyl derivative for in vitro magnetic resonance imaging of Alzheimer's disease.

    PubMed

    Zhou, Jingting; Fa, Huanbao; Yin, Wei; Zhang, Jin; Hou, Changjun; Huo, Danqun; Zhang, Dong; Zhang, Haifeng

    2014-04-01

    Superparamagnetic iron oxide nanoparticles (SPIONs) have been proposed for use in magnetic resonance imaging as versatile ultra-sensitive nanoprobes for Alzheimer's disease imaging. In this work, we synthetized an efficient contrast agent of Alzheimer's disease using 1,1-dicyano-2-[6-(dimethylamino)naphthalene-2-yl]propene (DDNP) carboxyl derivative to functionalize the surface of SPIONs. The DDNP-SPIONs are prepared by conjugating DDNP carboxyl derivative to oleic acid-treated SPIONs through ligand exchange. The structure, size distribution and magnetic property were identified by IR, TGA-DTA, XRD, TEM, Zetasizer Nano and VSM. TEM and Zetasizer Nano observations indicated that the DDNP-SPIONs are relatively mono-dispersed spherical distribution with an average size of 11.7nm. The DDNP-SPIONs were then further analyzed for their MRI relaxation properties using MR imaging and demonstrated high T2 relaxivity of 140.57s(-1)FemM(-1), and the vitro experiment that DDNP-SPIONs binding to ?-Amyloid aggregates were then investigated by fluorophotometry, the results showed that the combination had induced the fluorescence enhancement of the DDNP-SPIONs and displayed tremendous promise for use as a contrast agent of Alzheimer's disease in MRI. PMID:24582259

  11. Reduction of shading-derived artifacts in skin chromophore imaging without measurements or assumptions about the shape of the subject

    NASA Astrophysics Data System (ADS)

    Yoshida, Kenichiro; Nishidate, Izumi; Ojima, Nobutoshi; Iwata, Kayoko

    2014-01-01

    To quantitatively evaluate skin chromophores over a wide region of curved skin surface, we propose an approach that suppresses the effect of the shading-derived error in the reflectance on the estimation of chromophore concentrations, without sacrificing the accuracy of that estimation. In our method, we use multiple regression analysis, assuming the absorbance spectrum as the response variable and the extinction coefficients of melanin, oxygenated hemoglobin, and deoxygenated hemoglobin as the predictor variables. The concentrations of melanin and total hemoglobin are determined from the multiple regression coefficients using compensation formulae (CF) based on the diffuse reflectance spectra derived from a Monte Carlo simulation. To suppress the shading-derived error, we investigated three different combinations of multiple regression coefficients for the CF. In vivo measurements with the forearm skin demonstrated that the proposed approach can reduce the estimation errors that are due to shading-derived errors in the reflectance. With the best combination of multiple regression coefficients, we estimated that the ratio of the error to the chromophore concentrations is about 10%. The proposed method does not require any measurements or assumptions about the shape of the subjects; this is an advantage over other studies related to the reduction of shading-derived errors.

  12. Combined Optical Imaging and Mammography of the Healthy Breast: Optical Contrast Derived From Breast Structure and Compression

    PubMed Central

    Fang, Qianqian; Carp, Stefan A.; Selb, Juliette; Boverman, Greg; Zhang, Quan; Kopans, Daniel B.; Moore, Richard H.; Miller, Eric L.; Brooks, Dana H.; Boas, David A.

    2009-01-01

    In this paper, we report new progress in developing the instrument and software platform of a combined X-ray mammography/diffuse optical breast imaging system. Particularly, we focus on system validation using a series of balloon phantom experiments and the optical image analysis of 49 healthy patients. Using the finite-element method for forward modeling and a regularized Gauss-Newton method for parameter reconstruction, we recovered the inclusions inside the phantom and the hemoglobin images of the human breasts. An enhanced coupling coefficient estimation scheme was also incorporated to improve the accuracy and robustness of the reconstructions. The recovered average total hemoglobin concentration (HbT) and oxygen saturation (SO2) from 68 breast measurements are 16.2 ?m and 71%, respectively, where the HbT presents a linear trend with breast density. The low HbT value compared to literature is likely due to the associated mammographic compression. From the spatially co-registered optical/X-ray images, we can identify the chest-wall muscle, fatty tissue, and fibroglandular regions with an average HbT of 20.1±6.1 ?m for fibroglandular tissue, 15.4±5.0 ?m for adipose, and 22.2±7.3 ?m for muscle tissue. The differences between fibroglandular tissue and the corresponding adipose tissue are significant (p < 0.0001). At the same time, we recognize that the optical images are influenced, to a certain extent, by mammographical compression. The optical images from a subset of patients show composite features from both tissue structure and pressure distribution. We present mechanical simulations which further confirm this hypothesis. PMID:19116186

  13. Comparison of Simulated and Measured Synthetic Aperture Radar Image Spectra with Buoy-Derived Ocean Wave Spectra During the Shuttle Imaging Radar B Mission

    Microsoft Academic Search

    Werner Alpers; Claus Bruening; Karl Richter

    1986-01-01

    During the SIR-B mission over the North Sea, two successful synthetic aperture radar (SAR) data takes with simultaneous buoy measurements of ocean wave spectra have been obtained on October 6 and 8, 1984. On October 6, the SAR imaging of ocean waves was predicted as strongly nonlinear and on October 8 as almost linear. The SIR-B experiment confirmed the theoretical

  14. Synthesis and biological evaluation of technetium-99m-labeled deoxyglucose derivatives as imaging agents for tumor.

    PubMed

    Chen, Xiangji; Li, Liang; Liu, Fei; Liu, Boli

    2006-11-01

    Three deoxyglucose (DG) derivatives, S-DG, MAG(3)-DG and MAMA-BA-DG, were synthesized and labeled successfully with high labeling yields and high radio-chemical purities. Biodistribution in tumor-bearing mice demonstrated that these three new (99m)Tc-deoxyglucose derivatives showed accumulation in tumor and high tumor-to-muscle ratios. Among them, the (99m)Tc-MAG(3)-DG showed the best characteristics as a potential tumor marker for single photon emission computed tomography (SPECT). PMID:16931003

  15. New AMD3100 derivatives for CXCR4 chemokine receptor targeted molecular imaging studies: synthesis, anti-HIV-1 evaluation and binding affinities.

    PubMed

    Poty, Sophie; Désogère, Pauline; Goze, Christine; Boschetti, Frédéric; D'huys, Thomas; Schols, Dominique; Cawthorne, Christopher; Archibald, Stephen J; Maëcke, Helmut R; Denat, Franck

    2015-03-01

    CXCR4 is a target of growing interest for the development of new therapeutic drugs and imaging agents as its role in multiple disease states has been demonstrated. AMD3100, a CXCR4 chemokine receptor antagonist that is in current clinical use as a haematopoietic stem cell mobilising drug, has been widely studied for its anti-HIV properties, potential to inhibit metastatic spread of certain cancers and, more recently, its ability to chelate radiometals for nuclear imaging. In this study, AMD3100 is functionalised on the phenyl moiety to investigate the influence of the structural modification on the anti-HIV-1 properties and receptor affinity in competition with anti-CXCR4 monoclonal antibodies and the natural ligand for CXCR4, CXCL12. The effect of complexation of nickel(ii) in the cyclam cavities has been investigated. Two amino derivatives were obtained and are suitable intermediates for conjugation reactions to obtain CXCR4 molecular imaging agents. A fluorescent probe (BODIPY) and a precursor for (18)F (positron emitting isotope) radiolabelling were conjugated to validate this route to new CXCR4 imaging agents. PMID:25640878

  16. Photochemistryand Photobiology,2005, 81: 1499-1 504 Spectral Properties of Pro-multimodal Imaging Agents Derived

    E-print Network

    Larson-Prior, Linda

    radiometal) derived from 1,4,7,10-tetraazacy- clododecane-1,4,7,10-tetraacetic acid (DOTA) and cypate, a near orbitals of transition metal DOTA complexesor free metals and the p orbitalsof cypate chromophore could properties of cypate upon conjugation with DOTA and subsequent chelation with metals. The fluorescence

  17. Teaching Image Formation by Extended Light Sources: The Use of a Model Derived from the History of Science

    ERIC Educational Resources Information Center

    Dedes, Christos; Ravanis, Konstantinos

    2009-01-01

    This research, carried out in Greece on pupils aged 12-16, focuses on the transformation of their representations concerning light emission and image formation by extended light sources. The instructive process was carried out in two stages, each one having a different, distinct target set. During the first stage, the appropriate conflict…

  18. Characterization of conductive nanobiomaterials derived from viral assemblies by low-voltage STEM imaging and Raman scattering

    NASA Astrophysics Data System (ADS)

    Plascencia-Villa, Germán; Carreño-Fuentes, Liliana; Bahena, Daniel; José-Yacamán, Miguel; Palomares, Laura A.; Ramírez, Octavio T.

    2014-09-01

    New technologies require the development of novel nanomaterials that need to be fully characterized to achieve their potential. High-resolution low-voltage scanning transmission electron microscopy (STEM) has proven to be a very powerful technique in nanotechnology, but its use for the characterization of nanobiomaterials has been limited. Rotavirus VP6 self-assembles into nanotubular assemblies that possess an intrinsic affinity for Au ions. This property was exploited to produce hybrid nanobiomaterials by the in situ functionalization of recombinant VP6 nanotubes with gold nanoparticles. In this work, Raman spectroscopy and advanced analytical electron microscopy imaging with spherical aberration-corrected (Cs) STEM and nanodiffraction at low-voltage doses were employed to characterize nanobiomaterials. STEM imaging revealed the precise structure and arrangement of the protein templates, as well as the nanostructure and atomic arrangement of gold nanoparticles with high spatial sub-Angstrom resolution and avoided radiation damage. The imaging was coupled with backscattered electron imaging, ultra-high resolution scanning electron microscopy and x-ray spectroscopy. The hybrid nanobiomaterials that were obtained showed unique properties as bioelectronic conductive devices and showed enhanced Raman scattering by their precise arrangement into superlattices, displaying the utility of viral assemblies as functional integrative self-assembled nanomaterials for novel applications.

  19. Tropical forest phenology and metabolism: Integrated analysis of tower-mounted camera images and tower derived GPP for interpreting ecosystem scale processes

    NASA Astrophysics Data System (ADS)

    Wu, J.; Restrepo-Coupe, N.; Hayek, M.; Stark, S. C.; Smith, M.; Wiedemann, K.; Marostica, S.; Ferreira, M.; Woodcock, T.; Prohaska, N.; da Silva, R.; Nelson, B. W.; Huete, A. R.; Saleska, S. R.

    2013-12-01

    Seasonal and interannual patterns of leaf development and metabolism are a central topic of global change ecology. However, the seasonality of leaf development in tropical forests remains poorly understood due to the relatively low variation in climate, the high biodiversity of tropical biomes and the limitations of current observation techniques. In this study, we aim to demonstrate the feasibility of using near-surface remote sensing techniques to understand the phenology of an evergreen tropical forest (Tapajos National Forest or TNF site, Santarem, Para, Brazil), and how this phenology affects the metabolism of tropical vegetation. Two continuous years (2010-2011) of daily images from a tower mounted three-channel (red, green, and near-infrared) TetraCAM ADC camera were analyzed for this study. A new approach was developed based on an automatic image classification scheme which decomposed the images into two components (leaves and bare wood) to extract seasonality of leaf development. A confusion matrix method was used to assess the accuracy of image classification. MODIS EVI composites (MOD13Q1) were also acquired and processed for the TNF site (5km*5km). The camera based phenology information was first compared with MODIS EVI, and then combined with tower based eddy covariance measurements at the same site to quantify the effect of canopy-scale phenology on ecosystem metabolism. We found that: (1) Tower-based images revealed a clear seasonal pattern in leaf phenology that was supported by confusion matrix analysis. Matrix analysis gave a 96.7% user accuracy (user accuracy represents the probability that an image pixel classification actually corresponds to that category on the ground) for the leaf component, based on 24 images in 2010 (2 images per month). The tower-based pattern matched that retrieved from satellites (camera-sensed leaf phenology vs monthly MODIS EVI (01/2010-12/2011, R2=0.57, P-value<0.01). This suggests that quality-controlled MODIS EVI accurately captures optical phenology patterns observed near the ground in tropical regions, strong evidence against the previously suggested idea that tropical MODIS data are contaminated by atmospheric artifacts. (2) In particular, seasonal patterns observed from satellite and tower were robust to changes in solar zenith angle (SZA), which had a small effect in camera and satellite-derived leaf phenology, but this effect was secondary to the overall seasonal pattern of leaf development detected. (3) We also found the image classification scheme to be able to monitor the phenology of individual tree species. These results suggest this method to be a feasible way to monitor the complex phenology of a tropical forest system. (4)Net leaf production was extracted by applying a first derivative of monthly camera detected leaf component percentage (termed 'leaf phenology' in this study). Monthly net leaf production (02/2010-12/2011) was correlated with monthly eddy covariance derived light use efficiency (R2=0.59, P-value<0.01), but with ~4 months time lag. This might be associated with leaf age dependent physiological status (recently matured leaves have higher photosynthetic capacity compared with both newly emerged and previous growing leaves), a hypothesis that we are currently investigating.

  20. Global sensitivity analysis of computer models with functional inputs

    E-print Network

    Iooss, Bertrand

    2008-01-01

    Global sensitivity analysis is used to quantify the influence of uncertain input parameters on the response variability of a numerical model. The common quantitative methods are applicable to computer codes with scalar input variables. This paper aims to illustrate different variance-based sensitivity analysis techniques, based on the so-called Sobol indices, when some input variables are functional, such as stochastic processes or random spatial fields. In this work, we focus on large cpu time computer codes which need a preliminary meta-modeling step before performing the sensitivity analysis. We propose the use of the joint modeling approach, i.e., modeling simultaneously the mean and the dispersion of the code outputs using two interlinked Generalized Linear Models (GLM) or Generalized Additive Models (GAM). The ``mean'' model allows to estimate the sensitivity indices of each scalar input variables, while the ``dispersion'' model allows to derive the total sensitivity index of the functional input variab...

  1. Specificity of Cone Inputs to Macaque Retinal Ganglion Cells

    PubMed Central

    Sun, Hao; Smithson, Hannah E.; Zaidi, Qasim; Lee, Barry B.

    2010-01-01

    The specificity of cone inputs to ganglion cells has implications for the development of retinal connections and the nature of information transmitted to higher areas of the brain. We introduce a rapid and precise method for measuring signs and magnitudes of cone inputs to visual neurons. Colors of stimuli are modulated around circumferences of three color planes in clockwise and counterclockwise directions. For each neuron, the projection of the preferred vector in each plane was estimated by averaging the response phases to clockwise and counterclockwise modulation. The signs and weights of cone inputs were derived directly from the preferred vectors. The efficiency of the method enables us to measure cone inputs at different temporal frequencies and short-wavelength-sensitive (S) cone adaptation levels. The results show that S-cone inputs to the parvocellular and magnocellular ganglion cells are negligible, which implies underlying connectional specificity in the retinal circuitry. PMID:16424455

  2. Specificity of Cone Inputs to Macaque Retinal Ganglion Cells

    PubMed Central

    Sun, Hao; Smithson, Hannah E.; Zaidi, Qasim; Lee, Barry B.

    2008-01-01

    The specificity of cone inputs to ganglion cells has implications for the development of retinal connections and the nature of information transmitted to higher areas of the brain. We introduce a rapid and precise method for measuring signs and magnitudes of cone inputs to visual neurons. Colors of stimuli are modulated around circumferences of three color planes in clockwise and counterclockwise directions. For each neuron, the projection of the preferred vector in each plane was estimated by averaging the response phases to clockwise and counterclockwise modulation. The signs and weights of cone inputs were derived directly from the preferred vectors. The efficiency of the method enables us to measure cone inputs at different temporal frequencies and short-wavelength-sensitive (S) cone adaptation levels. The results show that S-cone inputs to the parvocellular and magnocellular ganglion cells are negligible, which implies underlying connectional specificity in the retinal circuitry. PMID:16424450

  3. Medical image integrity control and forensics based on watermarking--approximating local modifications and identifying global image alterations.

    PubMed

    Huang, H; Coatrieux, G; Shu, H Z; Luo, L M; Roux, Ch

    2011-01-01

    In this paper we present a medical image integrity verification system that not only allows detecting and approximating malevolent local image alterations (e.g. removal or addition of findings) but is also capable to identify the nature of global image processing applied to the image (e.g. lossy compression, filtering …). For that purpose, we propose an image signature derived from the geometric moments of pixel blocks. Such a signature is computed over regions of interest of the image and then watermarked in regions of non interest. Image integrity analysis is conducted by comparing embedded and recomputed signatures. If any, local modifications are approximated through the determination of the parameters of the nearest generalized 2D Gaussian. Image moments are taken as image features and serve as inputs to one classifier we learned to discriminate the type of global image processing. Experimental results with both local and global modifications illustrate the overall performances of our approach. PMID:22256212

  4. Evaluating an Alternative Model for the Input Function in FDG-PET Studies 1

    E-print Network

    Renaut, Rosemary

    Evaluating an Alternative Model for the Input Function in FDG-PET Studies 1 Hongbin Guo 2 Rosemary-derived expressions. The new model provides an effective means to recover the input function in FDG-PET studies as compared to other models. Key words: Input Function Estimation, FDG-PET, Quantification 1 Introduction

  5. DOWN-SCALING OF SEBAL DERIVED EVAPOTRANSPIRATION MAPS1 FROM MODIS (250m) TO LANDSAT (30m) SCALE2

    E-print Network

    Borchers, Brian

    1 DOWN-SCALING OF SEBAL DERIVED EVAPOTRANSPIRATION MAPS1 FROM MODIS (250m) TO LANDSAT (30m) SCALE2). This paper15 considers the feasibility of applying various down-scaling methods to combine MODIS and16 Landsat 7 and MODIS images. Two down-scaling procedures were evaluated:19 input down-scaling and output

  6. Novel ¹?F-labeled dibenzylideneacetone derivatives as potential positron emission tomography probes for in vivo imaging of ?-amyloid plaques.

    PubMed

    Li, Zijing; Cui, Mengchao; Zhang, Jinming; Dai, Jiapei; Zhang, Xiaojun; Chen, Peng; Jia, Hongmei; Liu, Boli

    2014-09-12

    A series of dibenzylideneacetones were synthesized and evaluated as imaging probes for ?-amyloid plaques. They displayed high binding affinity to A?(1-42) aggregates (K(i) = 6.4 for 8, K(i) = 3.0 for 9), and the high binding were confirmed by in vitro autoradiography with AD human and transgenic mouse brain sections. Two of them were selected for (18)F-labeling directly on the benzene ring. In biodistribution experiments, [(18)F]8 and [(18)F]9 displayed high initial uptakes (9.29 ± 0.41 and 5.38 ± 0.68% ID/g) and rapid washouts from the normal brain (brain(2 min)/brain(60 min) ratios of 21.6 and 13.4). These preliminary results suggest that [(18)F]8 and [(18)F]9 may be used as potential PET imaging agents for the detection of A? plaques in the brain. PMID:25063945

  7. Power regulation of kinematic control inputs for forward flying Drosophila

    NASA Astrophysics Data System (ADS)

    MacFarlane, Kenneth; Faruque, Imraan; Sean Humbert, J.

    2014-12-01

    The choices of insect wing kinematic programs is not well understood, particularly the mechanism by which an insect selects a distortion to achieve flight control. A methodology to evaluate prospective kinematic control inputs is presented based on the reachable states when control actuation was constrained to a unit of power. The method implements a computationally-derived reduced order model of the insect's flight dynamics combined with calculation of power requirement. Four kinematic inputs are evaluated based on this criterion for a Drosophila size insect in forward flight. Stroke bias is shown to be the dominant control input using this power normalized evaluation measure.

  8. Synthetic Morphology Using Alternative Inputs

    PubMed Central

    Tanaka, Hiromasa; Yi, Tau-Mu

    2009-01-01

    Designing the shape and size of a cell is an interesting challenge for synthetic biology. Prolonged exposure to the mating pheromone ?-factor induces an unusual morphology in yeast cells: multiple mating projections. The goal of this work was to reproduce the multiple projections phenotype in the absence of ?-factor using a gain-of-function approach termed “Alternative Inputs (AIs)”. An alternative input is defined as any genetic manipulation that can activate the signaling pathway instead of the natural input. Interestingly, none of the alternative inputs were sufficient to produce multiple projections although some produced a single projection. Then, we extended our search by creating all combinations of alternative inputs and deletions that were summarized in an AIs-Deletions matrix. We found a genetic manipulation (AI-Ste5p ste2?) that enhanced the formation of multiple projections. Following up this lead, we demonstrated that AI-Ste4p and AI-Ste5p were sufficient to produce multiple projections when combined. Further, we showed that overexpression of a membrane-targeted form of Ste5p alone could also induce multiple projections. Thus, we successfully re-engineered the multiple projections mating morphology using alternative inputs without ?-factor. PMID:19746161

  9. Images of Gravitational and Magnetic Phenomena Derived from Two-dimensional Back-projection Doppler Tomography of Interacting Binary Stars

    NASA Astrophysics Data System (ADS)

    Richards, Mercedes T.; Cocking, Alexander S.; Fisher, John G.; Conover, Marshall J.

    2014-11-01

    We have used two-dimensional back-projection Doppler tomography as a tool to examine the influence of gravitational and magnetic phenomena in interacting binaries that undergo mass transfer from a magnetically active star onto a non-magnetic main-sequence star. This multitiered study of over 1300 time-resolved spectra of 13 Algol binaries involved calculations of the predicted dynamical behavior of the gravitational flow and the dynamics at the impact site, analysis of the velocity images constructed from tomography, and the influence on the tomograms of orbital inclination, systemic velocity, orbital coverage, and shadowing. The H? tomograms revealed eight sources: chromospheric emission, a gas stream along the gravitational trajectory, a star-stream impact region, a bulge of absorption or emission around the mass-gaining star, a Keplerian accretion disk, an absorption zone associated with hotter gas, a disk-stream impact region, and a hot spot where the stream strikes the edge of a disk. We described several methods used to extract the physical properties of the emission sources directly from the velocity images, including S-wave analysis, the creation of simulated velocity tomograms from hydrodynamic simulations, and the use of synthetic spectra with tomography to sequentially extract the separate sources of emission from the velocity image. In summary, the tomography images have revealed results that cannot be explained solely by gravitational effects: chromospheric emission moving with the mass-losing star, a gas stream deflected from the gravitational trajectory, and alternating behavior between stream state and disk state. Our results demonstrate that magnetic effects cannot be ignored in these interacting binaries.

  10. Microphysical and optical properties of ice clouds derived from the Airborne Visible\\/Infrared Imaging Spectrometer measurements

    Microsoft Academic Search

    K. Meyer; P. Yang; B. Gao; W. Wiscombe; Y. X. Hu

    2004-01-01

    In this paper, we introduce a method to simultaneously retrieve ice crystal effective size and cirrus cloud optical thickness using 1.38- and 1.88-mu m cirrus reflectance from Airborne Visible\\/Infrared Imaging Spectrometer (AVIRIS) data. Atmospheric and surface effects are removed from this data to obtain isolated cirrus reflectance. An effective size and optical thickness look-up table has been produced for each

  11. MR Elastography Derived Shear Stiffness – A New Imaging Biomarker for the Assessment of Early Tumor Response to Chemotherapy

    PubMed Central

    Pepin, Kay M.; Chen, Jun; Glaser, Kevin J.; Mariappan, Yogesh K.; Reuland, Brian; Ziesmer, Steven; Carter, Rickey; Ansell, Stephen M.; Ehman, Richard L.; McGee, Kiaran P.

    2014-01-01

    Purpose The overall goal is to develop MR Elastography (MRE) derived shear stiffness as a biomarker for the early identification of chemotherapy response, allowing dose, agent type and treatment regimen to be tailored on a per patient basis, improving therapeutic outcome and minimizing normal tissue toxicity. The specific purpose of this study is to test the feasibility of this novel biomarker to measure the treatment response in a well-known chemotherapy model. Methods Tumors were grown in the right flank of genetically modified mice by subcutaneous injection of DoHH2 (non-Hodgkin’s lymphoma) cells. MRE was used to quantify tumor stiffness before and after injection of a chemotherapeutic agent or saline. Histological tests were also performed on the tumors. Results A significant decrease (P < 0.0001) in MRE-derived tumor shear stiffness was observed within 4 days of chemotherapy treatment, while no appreciable change was observed in saline-treated tumors. No significant change in volume occurred at this early stage, but there were decreased levels of cellular proliferation in chemotherapy-treated tumors. Conclusion These results demonstrate that MRE-derived estimates of shear stiffness reflect an initial response to cytotoxic therapy and suggest that this metric could be an early and sensitive biomarker of tumor response to chemotherapy. PMID:23801372

  12. Entropy-based measures of in vivo cilia-driven microfluidic mixing derived from quantitative optical imaging

    NASA Astrophysics Data System (ADS)

    Chandrasekera, Kenny; Jonas, Stephan; Bhattacharya, Dipankan; Khokha, Mustafa; Choma, Michael A.

    2012-02-01

    Motile cilia are cellular organelles that project from different epithelial surfaces including respiratory epithelium. They generate directional fluid flow that removes harmful pathogens and particulate matter from the respiratory system. While it has been known that primary ciliary dyskinesia increases the risk of recurrent pulmonary infections, there is now heightened interest in understanding the role that cilia play in a wide-variety of respiratory diseases. Different optical imaging technologies are being investigated to visualize cilia-driven fluid flow, and quantitative image analysis is used to generate measures of ciliary performance. Here, we demonstrate the quantification of in vivo cilia-driven microfluidic mixing using spatial and temporal measures of Shannon information entropy. Using videomicroscopy, we imaged in vivo cilia-driven fluid flow generated by the epidermis of the Xenopus tropicalis embryo. Flow was seeded with either dyes or microparticles. Both spatial and temporal measures of entropy show significant levels of mixing, with maximum entropy measures of ~6.5 (out of a possible range of 0 to 8). Spatial entropy measures showed localization of mixing "hot-spots" and "cold-spots" and temporal measures showed mixing throughout.In sum, entropy-based measures of microfluidic mixing can characterize in vivo cilia-driven fluid flow and hold the potential for better characterization of ciliary dysfunction.

  13. Correlations between Functional Imaging Markers Derived from PET/CT and Diffusion-Weighted MRI in Diffuse Large B-Cell Lymphoma and Follicular Lymphoma

    PubMed Central

    Wu, Xingchen; Pertovaara, Hannu; Korkola, Pasi; Dastidar, Prasun; Järvenpää, Ritva; Eskola, Hannu; Kellokumpu-Lehtinen, Pirkko-Liisa

    2014-01-01

    Objectives To investigate the correlations between functional imaging markers derived from positron emission tomography/computed tomography (PET/CT) and diffusion-weighted magnetic resonance imaging (DWI) in diffuse large B-cell lymphoma (DLBCL) and follicular lymphoma (FL). Further to compare the usefulness of these tumor markers in differentiating diagnosis of the two common types of Non-Hodgkin's lymphoma (NHL). Materials and Methods Thirty-four consecutive pre-therapy adult patients with proven NHL (23 DLBCL and 11 FL) underwent PET/CT and MRI examinations and laboratory tests. The maximum standardized uptake value (SUVmax), metabolic tumor volume (MTV), and metabolic tumor burden (MTB) were determined from the PET/CT images. DWI was performed in addition to conventional MRI sequences using two b values (0 and 800 s/mm2). The minimum and mean apparent diffusion coefficient (ADCmin and ADCmean) were measured on the parametric ADC maps. Results The SUVmax correlated inversely with the ADCmin (r?=??0.35, p<0.05). The ADCmin, ADCmean, serum thymidine kinase (TK), Beta 2-microglobulin (B2m), lactate dehydrogenase (LD), and C-reactive protein (CRP) correlated with both whole-body MTV and whole-body MTB (p<0.05 or 0.01). The SUVmax, TK, LD, and CRP were significantly higher in the DLBCL group than in the FL group. Receiver operating characteristic curve analysis showed that they were reasonable predictors in differentiating DLBCL from FL. Conclusions The functional imaging markers determined from PET/CT and DWI are associated, and the SUVmax is superior to the ADCmin in differentiating DLBCL from FL. All the measured serum markers are associated with functional imaging markers. Serum LD, TK, and CRP are useful in differentiating DLBCL from FL. PMID:24454777

  14. Comparison of Texture Features Derived from Static and Respiratory-Gated PET Images in Non-Small Cell Lung Cancer

    PubMed Central

    Yip, Stephen; McCall, Keisha; Aristophanous, Michalis; Chen, Aileen B.

    2014-01-01

    Background PET-based texture features have been used to quantify tumor heterogeneity due to their predictive power in treatment outcome. We investigated the sensitivity of texture features to tumor motion by comparing static (3D) and respiratory-gated (4D) PET imaging. Methods Twenty-six patients (34 lesions) received 3D and 4D [18F]FDG-PET scans before the chemo-radiotherapy. The acquired 4D data were retrospectively binned into five breathing phases to create the 4D image sequence. Texture features, including Maximal correlation coefficient (MCC), Long run low gray (LRLG), Coarseness, Contrast, and Busyness, were computed within the physician-defined tumor volume. The relative difference (?3D-4D) in each texture between the 3D- and 4D-PET imaging was calculated. Coefficient of variation (CV) was used to determine the variability in the textures between all 4D-PET phases. Correlations between tumor volume, motion amplitude, and ?3D-4D were also assessed. Results 4D-PET increased LRLG (?=?1%–2%, p<0.02), Busyness (?=?7%–19%, p<0.01), and decreased MCC (?=?1%–2%, p<7.5×10?3), Coarseness (?=?5%–10%, p<0.05) and Contrast (?=?4%–6%, p>0.08) compared to 3D-PET. Nearly negligible variability was found between the 4D phase bins with CV<5% for MCC, LRLG, and Coarseness. For Contrast and Busyness, moderate variability was found with CV?=?9% and 10%, respectively. No strong correlation was found between the tumor volume and ?3D-4D for the texture features. Motion amplitude had moderate impact on ? for MCC and Busyness and no impact for LRLG, Coarseness, and Contrast. Conclusions Significant differences were found in MCC, LRLG, Coarseness, and Busyness between 3D and 4D PET imaging. The variability between phase bins for MCC, LRLG, and Coarseness was negligible, suggesting that similar quantification can be obtained from all phases. Texture features, blurred out by respiratory motion during 3D-PET acquisition, can be better resolved by 4D-PET imaging. 4D-PET textures may have better prognostic value as they are less susceptible to tumor motion. PMID:25517987

  15. Images

    Microsoft Academic Search

    Russell K. Hobbie; Bradley J. Roth

    Images are very important in the remainder of this book. They may be formed by the eye, a camera, an xray machine, a nuclear\\u000a medicine camera, magnetic resonance imaging, or ultrasound. The concepts developed in Chapter 11 can be used to understand\\u000a and describe image quality. The same concepts are also used to reconstruct computed tomographic or magnetic resonance slice

  16. High-resolution intravital imaging reveals that blood derived macrophages but not resident microglia facilitate secondary axonal dieback in traumatic spinal cord injury

    PubMed Central

    Evans, Teresa A.; Barkauskas, Deborah S.; Myers, Jay; Hare, Elisabeth G.; You, Jingquang; Ransohoff, Richard M.; Huang, Alex Y.; Silver, Jerry

    2014-01-01

    After traumatic spinal cord injury, functional deficits increase as axons die back from the center of the lesion and the glial scar forms. Axonal die back occurs in two phases: an initial axon intrinsic stage that occurs over the first several hours and a secondary phase which takes place over the first few weeks after injury. Here, we examine the secondary phase, which is marked by infiltration of macrophages. Using powerful time lapse multi-photon imaging, we captured images of interactions between Cx3cr1+/GFP macrophages and microglia and Thy-1YFP axons in a mouse dorsal column crush spinal cord injury model. Over the first few weeks after injury, axonal retraction bulbs within the lesion are static except when axonal fragments are lost by a blebbing mechanism in response to physical contact followed by phagocytosis by mobile Cx3Cr1+/GFP cells. Utilizing a radiation chimera model to distinguish marrow-derived cells from radio-resistant CNS resident microglia, we determined that the vast majority of accumulated cells in the lesion are derived from the blood and only these are associated with axonal damage. Interestingly, CNS-resident Cx3Cr1+/GFP microglia did not increasingly accumulate nor participate in neuronal destruction in the lesion during this time period. Additionally, we found that the blood-derived cells consisted mainly of singly labeled Ccr2+/RFP macrophages, singly labeled Cx3Cr1+/GFP macrophages and a small population of double-labeled cells. Since all axon destructive events were seen in contact with a Cx3Cr1+/GFP cell, we infer that the CCR2 single positive subset is likely not robustly involved in axonal dieback. Finally, in our model, deletion of CCR2, a chemokine receptor, did not alter the position of axons after dieback. Understanding the in vivo cellular interactions involved in secondary axonal injury may lead to clinical treatment candidates involving modulation of destructive infiltrating blood monocytes. PMID:24468477

  17. Respiratory input in inhalation experiments.

    PubMed Central

    Opdam, J J

    1989-01-01

    The definition of the respiratory input in experimental human exposure to volatile solvents was examined on theoretical grounds. The respiratory rate of input may be defined as the rate of uptake that equals the inhaled minus exhaled amount per minute. In the present paper the rate of respiratory input is defined as the rate of the functional intake (RFI) which equals the product of the inhaled concentration (CI) and a functional alveolar ventilation (Va). The functional Va is a virtual alveolar volume per minute which equilibrates completely with the mixed venous blood. Human subjects were exposed simultaneously to tetrachloroethene (PER, perchloroethylene) and trichloroethene (TRI) in order to study the consequences of the application of both definitions. It is shown that when using the uptake as the respiratory input some misleading conclusions may be drawn on (a) the dependence of the metabolised fraction on the duration of exposure, (b) the dependence of the kinetic characteristic on the duration and route of administration, and (c) the changes of the rate of metabolism during exposure due to physical exercise. The respiratory input defined as the rate of functional intake (RFI) rejects these misleading conclusions. PMID:2930725

  18. Bis(methylpyridine)-EDTA derivative as a potential ligand for PET imaging: synthesis, complexation, and biological evaluation.

    PubMed

    Singh, Pooja; Aggarwal, Swati; Tiwari, Anjani K; Kumar, Vikas; Pratap, Ramendra; Chuttani, Krishna; Mishra, Anil K

    2014-12-01

    A novel transitional metal ligand derivatized from EDTA-conjugated 2-amino-4-methyl pyridine, an acyclic vehicle (EDTA-Mepy2 ) was designed, synthesized, and characterized for PET imaging with ??Ga. The drug likeliness and appropriate lipophilicity were first analyzed by molecular docking studies which shows interactive property of ligand with serum albumin protein (HSA: PDB 1E78), at Lys199, Arg257, and His242 residues, which make it more appropriate in transportation as a specific ligand for PET imaging. As a confirmation, binding constant of the ligand with human serum albumin was calculated at ?ex = 350 nm which was found to be 4.9 × 10³ m?¹. The pharmacokinetics of (68) Ga-EDTA-Mepy2 was analyzed by blood kinetics (t(1/2) slow: 3 h 56 min and t(1/2) fast: 32 min) and biodistribution (maximum % ID/g was found in kidney at 1 h). Further the capability of this ligand was analyzed as optical marker also, by recording ?ex = 380 nm, RFU = 8000; 710 nm, RFU = 1000 units at fixed ?em = 280 nm. Additionally, in physiological conditions where its stability was calculated, suggests 15-20 times selectivity over the endogenously present metal ions (KG aL /KZ nL = 14.3, KG aL /KC uL = 18.1). PMID:24894071

  19. Motion-compensated mega-voltage cone beam CT using the deformation derived directly from 2D projection images.

    PubMed

    Chen, Mingqing; Cao, Kunlin; Zheng, Yefeng; Siochi, R Alfredo C

    2013-08-01

    This paper presents a novel method for respiratory motion compensated reconstruction for cone beam computed tomography (CBCT). The reconstruction is based on a time sequence of motion vector fields, which is generated by a dynamic geometrical object shape model. The dynamic model is extracted from the 2D projection images of the CBCT. The process of the motion extraction is converted into an optimal 3D multiple interrelated surface detection problem, which can be solved by computing a maximum flow in a 4D directed graph. The method was tested on 12 mega-voltage (MV) CBCT scans from three patients. Two sets of motion-artifact-free 3D volumes, full exhale (FE) and full inhale (FI) phases, were reconstructed for each daily scan. The reconstruction was compared with three other motion-compensated approaches based on quantification accuracy of motion and size. Contrast-to-noise ratio (CNR) was also quantified for image quality. The proposed approach has the best overall performance, with a relative tumor volume quantification error of 3.39 ± 3.64% and 8.57 ± 8.31% for FE and FI phases, respectively. The CNR near the tumor area is 3.85 ± 0.42 (FE) and 3.58 ± 3.33 (FI). These results show the clinical feasibility to use the proposed method to reconstruct motion-artifact-free MVCBCT volumes. PMID:23247845

  20. Comparison of temporal and spectral scattering methods using acoustically large breast models derived from magnetic resonance images.

    PubMed

    Hesford, Andrew J; Tillett, Jason C; Astheimer, Jeffrey P; Waag, Robert C

    2014-08-01

    Accurate and efficient modeling of ultrasound propagation through realistic tissue models is important to many aspects of clinical ultrasound imaging. Simplified problems with known solutions are often used to study and validate numerical methods. Greater confidence in a time-domain k-space method and a frequency-domain fast multipole method is established in this paper by analyzing results for realistic models of the human breast. Models of breast tissue were produced by segmenting magnetic resonance images of ex vivo specimens into seven distinct tissue types. After confirming with histologic analysis by pathologists that the model structures mimicked in vivo breast, the tissue types were mapped to variations in sound speed and acoustic absorption. Calculations of acoustic scattering by the resulting model were performed on massively parallel supercomputer clusters using parallel implementations of the k-space method and the fast multipole method. The efficient use of these resources was confirmed by parallel efficiency and scalability studies using large-scale, realistic tissue models. Comparisons between the temporal and spectral results were performed in representative planes by Fourier transforming the temporal results. An RMS field error less than 3% throughout the model volume confirms the accuracy of the methods for modeling ultrasound propagation through human breast. PMID:25096103

  1. Quantization noise spectrum of double-loop sigma-delta converter with sinusoidal input

    Microsoft Academic Search

    S. Rangan; B. Leung

    1994-01-01

    An exact formula for the output noise spectrum of a double-loop sigma-delta modulator, under the no overloading assumption and with a sinusoidal input, is derived without the use of a white-noise model. In the case of a sinusoidal input with irrational input amplitude and digital frequency, the result agrees with the exact formula derived by ergodic theory for two-stage modulators.

  2. Quantization noise spectrum of double-loop sigma-delta converter with sinusoidal input

    Microsoft Academic Search

    Sundeep Rangan; Bosco Leung

    1993-01-01

    An exact formula for the output noise spectrum of a double-loop sigma-delta modulator with a sinusoidal input is derived without the use of a white-noise model. In the case of a sinusoidal input with irrational input amplitude and digital frequency, the result agrees with the exact formula derived by ergodic theory for two-stage modulators. In addition, the present method also

  3. LAT1 targeted delivery of methionine based imaging probe derived from M(III) metal ions for early diagnosis of proliferating tumours using molecular imaging modalities.

    PubMed

    Hazari, Puja Panwar; Prakash, Surbhi; Meena, Virendra K; Jaswal, Ambika; Khurana, Harleen; Mishra, Surabhi Kirti; Bhonsle, Hemanth Kumar; Singh, Lokendra; Mishra, Anil K

    2015-01-01

    We investigated the potential of DTPA-bis(Methionine), a target specific amino acid based probe for detection of L-type amino acid transporters (LAT1) known to over express in proliferating tumours using multimodality imaging. The ligand, DTPA-bis(Met) was readily converted to lanthanide complexes and was found capable of targeting cancer cells using multimodality imaging. DTPA-bis(Met) complexes were synthesized and characterized by mass spectroscopy. MR longitudinal relaxivity, r(1) = 4.067 ± 0.31 mM(-1) s(-1) and transverse relaxivity, r(2) = 8.61 ± 0.07 mM(-1) s(-1)of Gd(III)-DTPA-bis(Met) were observed at pH 7.4 at 7 T. Bright, localized fluorescence of Eu(III)-DTPA-bis(Met) was observed with standard microscopy and displacement studies indicated ligand functionality. K(D) value determined for Eu(III)-DTPA-bis(Met) on U-87 MG cells was found to be 17.3 pM and showed appreciable fluorescence within the cells. Radio HPLC showed a radiochemical purity more than 95% (specific activity = 400-500 MBq/?mol, labelling efficiency 78 %) for (68)Ga(III)-DTPA-bis(Met). Pre-treatment of xenografted U-87 MG athymic mice with (68)Ga(III)-DTPA-bis(Met) following unlabelled L-methionine administration reduced tumour uptake by 10-folds in Micro PET. These data support the specific binding of (68)Ga(III)-DTPA-bis(Met) to the LAT1 transporter. To summarize, this agent possesses high stability in biological environment and exhibits effective interaction with its LAT1 transporters giving high accumulation in tumour area, excellent tumour/non-tumour ratio and low non-specific retention in vivo. PMID:25329672

  4. Mass Exchange Processes with Input

    E-print Network

    P. L. Krapivsky

    2015-03-07

    We investigate a system of interacting clusters evolving through mass exchange and supplemented by input of small clusters. Three possibilities depending on the rate of exchange generically occur when input is homogeneous: continuous growth, gelation, and instantaneous gelation. We mostly study the growth regime using scaling methods. An exchange process with reaction rates equal to the product of reactant masses admits an exact solution which allows us to justify the validity of scaling approaches in this special case. We also investigate exchange processes with a localized input. We show that if the diffusion coefficients are mass-independent, the cluster mass distribution becomes stationary and develops an algebraic tail far away from the source.

  5. Input Type and Parameter Resetting: Is Naturalistic Input Necessary?

    ERIC Educational Resources Information Center

    Rothman, Jason; Iverson, Michael

    2007-01-01

    It has been argued that extended exposure to naturalistic input provides L2 learners with more of an opportunity to converge of target morphosyntactic competence as compared to classroom-only environments, given that the former provide more positive evidence of less salient linguistic properties than the latter (e.g., Isabelli 2004). Implicitly,…

  6. Image and in situ data integration to derive sawgrass density for surface flow modelling in the Everglades, Florida, USA

    USGS Publications Warehouse

    Jones, J.W.

    2000-01-01

    The US Geological Survey is building models of the Florida Everglades to be used in managing south Florida surface water flows for habitat restoration and maintenance. Because of the low gradients in the Everglades, vegetation structural characteristics are very important and greatly influence surface water flow and distribution. Vegetation density is being evaluated as an index of surface resistance to flow. Digital multispectral videography (DMSV) has been captured over several sites just before field collection of vegetation data. Linear regression has been used to establish a relationship between normalized difference vegetation index (NDVI) values computed from the DMSV and field-collected biomass and density estimates. Spatial analysis applied to the DMSV data indicates that thematic mapper (TM) resolution is at the limit required to capture land surface heterogeneity. The TM data collected close to the time of the DMSV will be used to derive a regional sawgrass density map.

  7. Image and in situ data integration to derive sawgrass density for surface flow modelling in the Everglades, Florida, USA

    USGS Publications Warehouse

    Jones, J.W.

    2001-01-01

    The US Geological Survey is building models of the Florida Everglades to be used in managing south Florida surface water flows for habitat restoration and maintenance. Because of the low gradients in the Everglades, vegetation structural characteristics are very important and greatly influence surface water flow and distribution. Vegetation density is being evaluated as an index of surface resistance to flow. Digital multispectral videography (DMSV) has been captured over several sites just before field collection of vegetation data. Linear regression has been used to establish a relationship between normalized difference vegetation index (NDVI) values computed from the DMSV and field-collected biomass and density estimates. Spatial analysis applied to the DMSV data indicates that thematic mapper (TM) resolution is at the limit required to capture land surface heterogeneity. The TM data collected close to the time of the DMSV will be used to derive a regional sawgrass density map.

  8. Fusion of 3D models derived from TLS and image-based techniques for CH enhanced documentation

    NASA Astrophysics Data System (ADS)

    Bastonero, P.; Donadio, E.; Chiabrando, F.; Spanò, A.

    2014-05-01

    Recognizing the various advantages offered by 3D new metric survey technologies in the Cultural Heritage documentation phase, this paper presents some tests of 3D model generation, using different methods, and their possible fusion. With the aim to define potentialities and problems deriving from integration or fusion of metric data acquired with different survey techniques, the elected test case is an outstanding Cultural Heritage item, presenting both widespread and specific complexities connected to the conservation of historical buildings. The site is the Staffarda Abbey, the most relevant evidence of medieval architecture in Piedmont. This application faced one of the most topical architectural issues consisting in the opportunity to study and analyze an object as a whole, from twice location of acquisition sensors, both the terrestrial and the aerial one. In particular, the work consists in the evaluation of chances deriving from a simple union or from the fusion of different 3D cloudmodels of the abbey, achieved by multi-sensor techniques. The aerial survey is based on a photogrammetric RPAS (Remotely piloted aircraft system) flight while the terrestrial acquisition have been fulfilled by laser scanning survey. Both techniques allowed to extract and process different point clouds and to generate consequent 3D continuous models which are characterized by different scale, that is to say different resolutions and diverse contents of details and precisions. Starting from these models, the proposed process, applied to a sample area of the building, aimed to test the generation of a unique 3Dmodel thorough a fusion of different sensor point clouds. Surely, the describing potential and the metric and thematic gains feasible by the final model exceeded those offered by the two detached models.

  9. THE PULSATION OF chi CYGNI IMAGED BY OPTICAL INTERFEROMETRY: A NOVEL TECHNIQUE TO DERIVE DISTANCE AND MASS OF MIRA STARS

    SciTech Connect

    Lacour, S.; Perrin, G.; Haubois, X.; Poncelet, A. [Observatoire de Paris, LESIA, CNRS/UMR 8109, 92190 Meudon (France); Thiebaut, E. [Centre de Recherche Astrophysique de Lyon, CNRS/UMR 5574, 69561 Saint Genis Laval (France); Meimon, S. [Office National d'Etudes et de Recherches Aeronautiques, DOTA, 92322 Chatillon (France); Pedretti, E. [School of Physics and Astronomy, University of St. Andrews, North Haugh, St Andrews KY16 9SS (United Kingdom); Ridgway, S. T. [National Optical Astronomy Observatory, P.O. Box 26732, Tucson, AZ 85726-6732 (United States); Monnier, J. D. [University of Michigan, Astronomy Department, 914 Dennison Bldg., 500 Church Street, Ann Arbor, MI 40109 (United States); Berger, J. P. [LAOG-UMR 5571, CNRS and Universite Joseph Fourier, BP 53, 38041 Grenoble (France); Schuller, P. A. [Institut d'Astrophysique Spatiale, CNRS/UMR 8617, Universite Paris-Sud, 91405 Orsay (France); Woodruff, H. [Sydney Institute for Astronomy (SIfA), School of Physics, University of Sydney, NSW 2006 (Australia); Le Coroller, H. [Observatoire de Haute-Provence, OHP/CNRS, F-04870 St. Michel l'Observatoire (France); Millan-Gabet, R. [Michelson Science Center, California Institute of Technology, MS 100-22, Pasadena, CA 91125 (United States); Lacasse, M. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Traub, W. [Jet Propulsion Laboratory, California Institute of Technology, M/S 301-451, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States)

    2009-12-10

    We present infrared interferometric imaging of the S-type Mira star chi Cygni. The object was observed at four different epochs in 2005-2006 with the Infrared-Optical Telescope Array optical interferometer (H band). Images show up to 40% variation in the stellar diameter, as well as significant changes in the limb darkening and stellar inhomogeneities. Model fitting gave precise time-dependent values of the stellar diameter, and reveals presence and displacement of a warm molecular layer. The star radius, corrected for limb darkening, has a mean value of 12.1 mas and shows a 5.1 mas amplitude pulsation. Minimum diameter was observed at phase 0.94 +- 0.01. Maximum temperature was observed several days later at phase 1.02 +- 0.02. We also show that combining the angular acceleration of the molecular layer with CO (DELTAv = 3) radial velocity measurements yields a 5.9 +- 1.5 mas parallax. The constant acceleration of the CO molecules-during 80% of the pulsation cycle-lead us to argument for a free-falling layer. The acceleration is compatible with a gravitational field produced by a 2.1{sup +1.5} {sub -0.7} solar mass star. This last value is in agreement with fundamental mode pulsator models. We foresee increased development of techniques consisting in combining radial velocity with interferometric angular measurements, ultimately allowing total mapping of the speed, density, and position of the diverse species in pulsation-driven atmospheres.

  10. Synthesis, radiolabeling and evaluation of novel 4-oxo-quinoline derivatives as PET tracers for imaging cannabinoid type 2 receptor.

    PubMed

    Slavik, Roger; Herde, Adrienne Müller; Bieri, Daniel; Weber, Markus; Schibli, Roger; Krämer, Stefanie D; Ametamey, Simon M; Mu, Linjing

    2015-03-01

    Our goal is to develop a highly specific and selective PET brain tracer for imaging CB2 expression in patients with neuroinflammatory diseases. Based on our previous findings on a carbon-11 labeled 4-oxo-quinoline structure, designated KD2, further structural optimizations were performed, which led to the discovery of N-(1-adamantyl)-1-(2-ethoxyethyl)-8-methoxy-4-oxo-1,4-dihydroquinoline-3-carboxamide (RS-016). Compared to KD2, RS-016 exhibits a higher binding affinity towards CB2 (Ki = 0.7 nM) with a selectivity over CB1 of >10,000 and lower lipophilicity (logD7.4 = 2.78). [(11)C]RS-016 was obtained in ?99% radiochemical purity and up to 850GBq/?mol specific radioactivity at the end of synthesis. In vitro autoradiography on rodent spleen tissue showed high specific binding to CB2. [(11)C]RS-016 was stable in vitro in rodent and human plasma over 40 min, whereas 47% intact compound was found in vivo in rat blood plasma 20 min post injection (p.i.). High specific binding to CB2 was observed in murine spleen tissues and postmortem ALS patient spinal cord tissues in vitro autoradiography, ex vivo biodistribution data confirmed the high and specific uptake of [(11)C]RS-016 in spleen region in rats. In vivo specificity of [(11)C]RS-016 could also be shown in brain by PET imaging using a murine neuroinflammation model, which has higher CB2 receptor expression level in the brain induced by lipopolysaccharide (LPS) application. PMID:25599952

  11. Selective detection of volatile organic compounds by spectral imaging of porphyrin derivatives bound to TiO2 porous films.

    PubMed

    Roales, Javier; Pedrosa, José M; Castillero, Pedro; Cano, Manuel; Richardson, Tim H; Barranco, Ángel; González-Elipe, Agustín R

    2012-10-24

    In this work, the carboxylic acid derivatives of a free-base porphyrin, 5,10,15,20-tetrakis(4-carboxyphenyl)-21H,23H-porphyrin, and 10 of its metal derivatives (TCPPs) have been used for optical gas sensing. For this purpose, microstructured columnar TiO(2) thin films prepared by GAPVD (glancing angle physical vapor deposition) have been used as host materials for the porphyrins as they are non-dispersive and porous, allowing their use for UV-visible spectroscopy and gas sensing. The chemical binding between the dye molecules and the TiO(2) has been studied through infrared spectroscopy, and the obtained spectral changes have been found to be compatible with chelating and/or bidentate binding modes of the carboxylate groups on the TiO(2) surface. When hosted in the film, the UV-visible spectra of the porphyrins featured a blue shift and broadening of the Soret band with respect to the solution, which has been attributed to the formation of ?-? aggregates between porphyrin molecules. The composite porphyrin/TiO(2) films obtained from each of the 11 porphyrins have been exposed to 12 different volatile organic compounds (VOCs), and their respective gas-sensitive properties have been analyzed as a function of the spectral changes in their Soret band region in the presence of the analytes. The set of composite films has shown high selectivity to the analyzed volatile compounds. For each analyte, an innovative way of showing the different responses has been developed. By means of this procedure, an imagelike recognition pattern has been obtained, which allows an easy identification of every compound. The kinetics of the exposure to several analytes showed a fast, reversible and reproducible response, with response times of a few seconds, which has been attributed to both the sensitivity of the porphyrins and the high porosity of the TiO(2) films. Also, increasing concentrations of the analytes resulted in an increase in the magnitude of the response, indicating that the sensor behavior is also concentration-dependent. PMID:22985094

  12. Validation of a paleo river system derived by ground based electromagnetic induction measurements with satellite based RapidEye images

    NASA Astrophysics Data System (ADS)

    Rudolph, Sebastian; von Hebel, Christian; Ali, Mohammed; Stadler, Anja; Herbst, Michael; Montzka, Carsten; Pätzold, Stefan; Weihermüller, Lutz; van der Kruk, Jan; Vereecken, Harry

    2013-04-01

    Morphological remnants of an inactive river system that has been filled by younger sediments can provide datable proxies about past climatic conditions. However, sediment composition of their infillings is a challenge for agriculture, in particular for precision agriculture. Differential crop development and yield reduction are often a consequence of lateral and vertical textural inhomogeneities. Several studies have shown that buried river systems can be traced by the use of remote sensing. However, the appearance of crop marks strongly depends on environmental conditions, and therefore, the reliance of remotely acquired data can become time and cost expensive. Soil physical properties which are related to textural differences can be mapped fast and cost-effective by the use of near surface geophysics. Especially electromagnetic induction (EMI), which measures soil apparent conductivity (ECa), has become a tool of choice to characterize large areas in high resolution. The introduction of multiple coil EMI systems as well as the quantification of respective measurements enables a reliable multilayer inversion. The aim of this study was to map a postglacial river system on agricultural fields and to mark out buried remains such as trenches and bomb craters of World War II. In summer 2012 ten fields (17 ha) were mapped with the CMD MiniExplorer, a multiple coil EMI system especially appropriate for near surface applications, after the harvest of winter wheat and sugar beet. At elevated sandy sites meander like patterns with higher conductivity were mapped. ECa measurements were verified by textural data taken from directed soil samples and vertical ECa logs. Sediment thickness was evaluated on soil cores and electrical resistivity tomography (ERT) transects. Furthermore, ERT quantified ECa measurements were correlated with satellite as well as destructive derived leaf area index (LAI) measurements. In 3 of 71 LAI maps derived by multispectral RapidEye imagery crop marks were clearly visible following a dry season in spring 2011. These patterns are in coincidence with higher conductivity patterns caused by a higher amount of silt and clay. Good correlations were found for LAI measurements taken during a growing season with underlying sediments especially in the early stages of plant development. Finally, ECa measurements of two heterogeneous fields were used for a 3D layer inversion which will be further implemented into landscape models. This study shows that multiple EMI measurements can be successfully used to recover buried river systems, highlight possible sample locations and support farmers to manage their fields more precisely.

  13. 7 CFR 3430.907 - Stakeholder input.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...2010-01-01 2010-01-01 false Stakeholder input. 3430.907 Section 3430...Competitive Grants Program § 3430.907 Stakeholder input. CSREES shall seek and obtain stakeholder input through a variety of forums...

  14. Systems and methods for reconfiguring input devices

    NASA Technical Reports Server (NTRS)

    Lancaster, Jeff (Inventor); De Mers, Robert E. (Inventor)

    2012-01-01

    A system includes an input device having first and second input members configured to be activated by a user. The input device is configured to generate activation signals associated with activation of the first and second input members, and each of the first and second input members are associated with an input function. A processor is coupled to the input device and configured to receive the activation signals. A memory coupled to the processor, and includes a reconfiguration module configured to store the input functions assigned to the first and second input members and, upon execution of the processor, to reconfigure the input functions assigned to the input members when the first input member is inoperable.

  15. Lab Inputs for Common Micros.

    ERIC Educational Resources Information Center

    Tinker, Robert

    1984-01-01

    The game paddle inputs of Apple microcomputers provide a simple way to get laboratory measurements into the computer. Discusses these game paddles and the necessary interface software. Includes schematics for Apple built-in paddle electronics, TRS-80 game paddle I/O, Commodore circuit for user port, and bus interface for Sinclair/Timex, Commodore,…

  16. Reflectometer for receiver input system

    NASA Technical Reports Server (NTRS)

    Stelzried, C. T.

    1968-01-01

    Reflectometer, built into a microwave input system, measures the match of devices in the waveguide system of tracking receivers. Match measurements can be made on a routine calibration basis. It was installed in the S-band receiving system in the feed cone of the 210-ft antenna.

  17. Signal Prediction With Input Identification

    NASA Technical Reports Server (NTRS)

    Juang, Jer-Nan; Chen, Ya-Chin

    1999-01-01

    A novel coding technique is presented for signal prediction with applications including speech coding, system identification, and estimation of input excitation. The approach is based on the blind equalization method for speech signal processing in conjunction with the geometric subspace projection theory to formulate the basic prediction equation. The speech-coding problem is often divided into two parts, a linear prediction model and excitation input. The parameter coefficients of the linear predictor and the input excitation are solved simultaneously and recursively by a conventional recursive least-squares algorithm. The excitation input is computed by coding all possible outcomes into a binary codebook. The coefficients of the linear predictor and excitation, and the index of the codebook can then be used to represent the signal. In addition, a variable-frame concept is proposed to block the same excitation signal in sequence in order to reduce the storage size and increase the transmission rate. The results of this work can be easily extended to the problem of disturbance identification. The basic principles are outlined in this report and differences from other existing methods are discussed. Simulations are included to demonstrate the proposed method.

  18. SAM: an improved input device

    Microsoft Academic Search

    L. T. Hauck

    1992-01-01

    SAM allows people to communicate by sending Morse code with a single switch. Unlike most Morse code input devices, SAM allows extreme latitude in the timing of dots and dashes. This makes it usable by people who have trouble mastering the precise timing of conventional Morse code. SAM is portable and inexpensive-it costs about $50 to build and runs on

  19. Morphology of an ICME-event derived by Multi-point in Situ and Heliospheric Imaging Data

    NASA Astrophysics Data System (ADS)

    Rollett, Tanja; Möstl, Christian; Temmer, Manuela; Veronig, Astrid M.; Frahm, Rudy A.; Davies, Jackie A.; Vrsnak, Bojan; Farrugia, Charles J.; Amerstorfer, Ute V.

    2014-05-01

    We show the analysis of an outstanding fast interplanetary coronal mass ejection (ICME) of 07 March 2012, which has been observed stereoscopically from both STEREO spacecraft. Assuming self-similar expansion and constant direction of motion we derive the kinematical profiles for the eastern and the western part of the roughly Earth-directed ICME. As additional constraints we use the huge advantage of in situ measurements at various locations during the ICME's propagation, namely from Venus Express, Messenger, Wind and Mars Express. We found that the eastern part of the ICME had a much higher propagation speed than its western part. Using the drag-based model, a model for the propagation of ICMEs in the inner heliosphere, we analyzed the influence of the drag on both sides of the ICME due to the surrounding solar wind conditions. These different solar wind conditions could have been the reason for the differing velocities and therefore for a distortion of the ICME front. These studies are fundamental in order to deepen the understanding of ICME evolution and to enhance existing forecasting methods.

  20. Photosensitive nanocapsules for use in imaging from poly(styrene-co-divinylbenzene) cross-linked with coumarin derivatives.

    PubMed

    Sierant, Malgorzata; Paluch, Piotr; Florczak, Marcin; Rozanski, Artur; Miksa, Beata

    2013-11-01

    The study objective was to generate biocompatible probes and develop a stable macromolecule imaging system that are based on nanolipopolymersomes and can be used in living cells. We synthesized nanolipopolymersomes with a fluorescent polymer wall surrounded by an outer phospholipid shell that exhibits potential for the controlled delivery of diagnostic agents to cells. We describe a new type of probe suitable for dual detection methods (spectrophotometric and fluorescence). This aspect makes it unique among currently available probes because allows it to be detected with greater accuracy. We developed a highly fluorescent coumarinated polymer to overcome the limited brightness of conventional dyes with insufficient for long-term photostablility. Hydrophilic dyes (Lucifer yellow, Procion red, Procion blue) are entrapped in the aqueous core of stable polymeric nanocapsules with coumarin 6 embedded in a nanometre-thick poly(styrene-co-divinylbenzene) wall. Target compounds can be incorporated into nanocapsules in a single step. The hydrophilic phospholipids outer shell ensures biocompatibility and facilitates cell penetration. In this way, the novel fluorescent hybrid materials can help of nanotechnology. PMID:23893031

  1. Evaluation of monthly rainfall estimates derived from the special sensor microwave/imager (SSM/I) over the tropical Pacific

    NASA Technical Reports Server (NTRS)

    Berg, Wesley; Avery, Susan K.

    1995-01-01

    Estimates of monthly rainfall have been computed over the tropical Pacific using passive microwave satellite observations from the special sensor microwave/imager (SSM/I) for the period from July 1987 through December 1990. These monthly estimates are calibrated using data from a network of Pacific atoll rain gauges in order to account for systematic biases and are then compared with several visible and infrared satellite-based rainfall estimation techniques for the purpose of evaluating the performance of the microwave-based estimates. Although several key differences among the various techniques are observed, the general features of the monthly rainfall time series agree very well. Finally, the significant error sources contributing to uncertainties in the monthly estimates are examined and an estimate of the total error is produced. The sampling error characteristics are investigated using data from two SSM/I sensors and a detailed analysis of the characteristics of the diurnal cycle of rainfall over the oceans and its contribution to sampling errors in the monthly SSM/I estimates is made using geosynchronous satellite data. Based on the analysis of the sampling and other error sources the total error was estimated to be of the order of 30 to 50% of the monthly rainfall for estimates averaged over 2.5 deg x 2.5 deg latitude/longitude boxes, with a contribution due to diurnal variability of the order of 10%.

  2. Digital image processing of vascular angiograms

    NASA Technical Reports Server (NTRS)

    Selzer, R. H.; Blankenhorn, D. H.; Beckenbach, E. S.; Crawford, D. W.; Brooks, S. H.

    1975-01-01

    A computer image processing technique was developed to estimate the degree of atherosclerosis in the human femoral artery. With an angiographic film of the vessel as input, the computer was programmed to estimate vessel abnormality through a series of measurements, some derived primarily from the vessel edge information and others from optical density variations within the lumen shadow. These measurements were combined into an atherosclerosis index, which was found to correlate well with both visual and chemical estimates of atherosclerotic disease.

  3. Evaluation of SIR-A (Shuttle Imaging Radar) images from the Tres Marias region (Minas Gerais State, Brazil) using derived spatial features and registration with MSS-LANDSAT images

    NASA Technical Reports Server (NTRS)

    Parada, N. D. J. (principal investigator); Kux, H. J. H.; Dutra, L. V.

    1984-01-01

    Two image processing experiments are described using a MSS-LANDSAT scene from the Tres Marias region and a shuttle Imaging Radar SIR-A image digitized by a vidicon scanner. In the first experiment the study area is analyzed using the original and preprocessed SIR-A image data. The following thematic classes are obtained: (1) water, (2) dense savanna vegetation, (3) sparse savanna vegetation, (4) reforestation areas and (5) bare soil areas. In the second experiment, the SIR-A image was registered together with MSS-LANDSAT bands five, six, and seven. The same five classes mentioned above are obtained. These results are compared with those obtained using solely MSS-LANDSAT data. The spatial information as well as coregistered SIR-A and MSS-LANDSAT data can increase the separability between classes, as compared to the use of raw SIR-A data solely.

  4. Last developments of the EUMETSAT Atmospheric Motion Vector product derived from MSG images for assimilation in NWP models

    NASA Astrophysics Data System (ADS)

    Borde, Regis; Bertil Gustafsson, Jörgen; de Smet, Arthur; Dew, Greg

    2010-05-01

    Atmospheric Motion Vectors (AMVs) are one of the most important products derived from all geostationary satellites, because they constitute a very important part of the observation data provided to Numerical Weather Prediction models. The Height Assignment (HA) is currently the most difficult task in the AMV extraction scheme. Several sources of error can be introduced at the height assignment step, but one of the main difficulties is to clearly identify the pixels that lead the tracking process in the tracer box, in order to select them for the HA calculation. A good pixel selection process should ensure to keep a direct link between the feature really tracked and the calculation of the height. The most common method sorts the coldest pixels in the target box and uses them to calculate the AMV height. However, recent work showed that some of the coldest pixels can have very small and/or negative contribution to the cross correlation process. Following these findings, it is then proposed to use individual pixel contribution to the cross correlation coefficient information in the pixel selection process, in order to get a closer link between the tracked feature tracked and the HA. This method has been tested on a parallel chain at EUMETSAT for two separated periods of one month. This presentation summarizes the main results of these operational tests, which show some improvements of the new scheme on the AMV product for both the VIS0.8, HRV and IR10.8 channels, increasing the total amount of good AMVs (Quality Index QI>80) and also the amount of good AMV/radiosonde collocations. Speed biases and RMS against radiosonde observations are generally a bit larger, especially the known slow bias observed at high levels for IR10.8 AMVs, but are calculated on a bigger amount of data.

  5. An Interface for Melody Input Lutz Prechelt and Rainer Typke

    E-print Network

    Prechelt, Lutz

    performance figures, and an error analysis. Categories and Subject Descriptors: E.4 [Data]: Coding]: Miscellaneous General Terms: Algorithms, Human Factors, Performance Additional Key Words and Phrases: input mode evaluation of the new interface, including the derivation of suitable system parameters, resulting

  6. Input space versus feature space in kernel-based methods

    Microsoft Academic Search

    Bernhard Schölkopf; Sebastian Mika; Christopher J. C. Burges; Phil Knirsch; Klaus-robert Müller; Gunnar Rätsch; Alexander J. Smola

    1999-01-01

    This paper collects some ideas targeted at advancing our understanding of the feature spaces associated with support vector (SV) kernel functions. We first discuss the geometry of feature space. In particular, we review what is known about the shape of the image of input space under the feature space map, and how this influences the capacity of SV methods. Following

  7. Hyperpolarized 13C spectroscopic imaging informs on hypoxia-inducible factor-1 and Myc activity downstream of platelet-derived growth factor receptor

    PubMed Central

    Dafni, Hagit; Larson, Peder E.Z; Hu, Simon; Yoshihara, Hikari A.I.; Ward, Christopher S.; Venkatesh, Humsa S.; Wang, Chunsheng; Zhang, Xiaoliang; Vigneron, Daniel B.; Ronen, Sabrina M.

    2010-01-01

    The recent development of hyperpolarized 13C magnetic resonance spectroscopic imaging (MRSI) provides a novel method for in-vivo metabolic imaging with potential applications for detection of cancer and response to treatment. Chemotherapy-induced apoptosis was shown to decrease the flux of hyperpolarized 13C-label from pyruvate to lactate due to depletion of NADH, the coenzyme of lactate dehydrogenase (LDH). In contrast, we show here that in PC-3MM2 tumors, inhibition of platelet-derived growth factor receptor with imatinib reduces the conversion of hyperpolarized pyruvate to lactate by lowering the expression of LDH itself. This was accompanied by reduced expression of vascular endothelial growth factor and glutaminase, and is likely mediated by reduced expression of their transcriptional factors hypoxia-inducible factor-1 and c-Myc. Our results indicate that hyperpolarized 13C MRSI could potentially detect the molecular effect of various cell-signaling inhibitors, thus providing a radiation-free method to predict tumor response. PMID:20858719

  8. A 18F-labeled saxitoxin derivative for in vivo PET-MR imaging of voltage-gated sodium channel expression following nerve injury.

    PubMed

    Hoehne, Aileen; Behera, Deepak; Parsons, William H; James, Michelle L; Shen, Bin; Borgohain, Preeti; Bodapati, Deepika; Prabhakar, Archana; Gambhir, Sanjiv S; Yeomans, David C; Biswal, Sandip; Chin, Frederick T; Du Bois, J

    2013-12-01

    Both chronic and neuropathic pain conditions are associated with increased expression of certain voltage-gated sodium ion channel (NaV) isoforms in peripheral sensory neurons. A method for noninvasive imaging of these channels could represent a powerful tool for investigating aberrant expression of NaV and its role in pain pathogenesis. Herein, we describe the synthesis and evaluation of a positron emission tomography (PET) radiotracer targeting NaVs, the design of which is based on the potent, NaV-selective inhibitor saxitoxin. Both autoradiography analysis of sciatic nerves excised from injured rats as well as whole animal PET-MR imaging demonstrate that a systemically administered [(18)F]-labeled saxitoxin derivative concentrates at the site of nerve injury, consistent with upregulated sodium channel expression following axotomy. This type of PET agent has potential use for serial monitoring of channel expression levels at injured nerves throughout wound healing and/or following drug treatment. Such information may be correlated with pain behavioral analyses to help shed light on the complex molecular processes that underlie pain sensation. PMID:24261833

  9. Intravital and Whole-Organ Imaging Reveals Capture of Melanoma-Derived Antigen by Lymph Node Subcapsular Macrophages Leading to Widespread Deposition on Follicular Dendritic Cells

    PubMed Central

    Moalli, Federica; Proulx, Steven T.; Schwendener, Reto; Detmar, Michael; Schlapbach, Christoph; Stein, Jens V.

    2015-01-01

    Aberrant antigens expressed by tumor cells, such as in melanoma, are often associated with humoral immune responses, which may in turn influence tumor progression. Despite recent data showing the central role of adaptive immune responses on cancer spread or control, it remains poorly understood where and how tumor-derived antigen (TDA) induces a humoral immune response in tumor-bearing hosts. Based on our observation of TDA accumulation in B cell areas of lymph nodes (LNs) from melanoma patients, we developed a pre-metastatic B16.F10 melanoma model expressing a fluorescent fusion protein, tandem dimer tomato, as a surrogate TDA. Using intravital two-photon microscopy (2PM) and whole-mount 3D LN imaging of tumor-draining LNs in immunocompetent mice, we report an unexpectedly widespread accumulation of TDA on follicular dendritic cells (FDCs), which were dynamically scanned by circulating B cells. Furthermore, 2PM imaging identified macrophages located in the subcapsular sinus of tumor-draining LNs to capture subcellular TDA-containing particles arriving in afferent lymph. As a consequence, depletion of macrophages or genetic ablation of B cells and FDCs resulted in dramatically reduced TDA capture in tumor-draining LNs. In sum, we identified a major pathway for the induction of humoral responses in a melanoma model, which may be exploitable to manipulate anti-TDA antibody production during cancer immunotherapy.

  10. Intravital and whole-organ imaging reveals capture of melanoma-derived antigen by lymph node subcapsular macrophages leading to widespread deposition on follicular dendritic cells.

    PubMed

    Moalli, Federica; Proulx, Steven T; Schwendener, Reto; Detmar, Michael; Schlapbach, Christoph; Stein, Jens V

    2015-01-01

    Aberrant antigens expressed by tumor cells, such as in melanoma, are often associated with humoral immune responses, which may in turn influence tumor progression. Despite recent data showing the central role of adaptive immune responses on cancer spread or control, it remains poorly understood where and how tumor-derived antigen (TDA) induces a humoral immune response in tumor-bearing hosts. Based on our observation of TDA accumulation in B cell areas of lymph nodes (LNs) from melanoma patients, we developed a pre-metastatic B16.F10 melanoma model expressing a fluorescent fusion protein, tandem dimer tomato, as a surrogate TDA. Using intravital two-photon microscopy (2PM) and whole-mount 3D LN imaging of tumor-draining LNs in immunocompetent mice, we report an unexpectedly widespread accumulation of TDA on follicular dendritic cells (FDCs), which were dynamically scanned by circulating B cells. Furthermore, 2PM imaging identified macrophages located in the subcapsular sinus of tumor-draining LNs to capture subcellular TDA-containing particles arriving in afferent lymph. As a consequence, depletion of macrophages or genetic ablation of B cells and FDCs resulted in dramatically reduced TDA capture in tumor-draining LNs. In sum, we identified a major pathway for the induction of humoral responses in a melanoma model, which may be exploitable to manipulate anti-TDA antibody production during cancer immunotherapy. PMID:25821451

  11. Synthesis, (68)Ga-Radiolabeling, and Preliminary In Vivo Assessment of a Depsipeptide-Derived Compound as a Potential PET/CT Infection Imaging Agent.

    PubMed

    Mokaleng, Botshelo B; Ebenhan, Thomas; Ramesh, Suhas; Govender, Thavendran; Kruger, Hendrik G; Parboosing, Raveen; Hazari, Puja P; Mishra, Anil K; Marjanovic-Painter, Biljana; Zeevaart, Jan R; Sathekge, Mike M

    2015-01-01

    Noninvasive imaging is a powerful tool for early diagnosis and monitoring of various disease processes, such as infections. An alarming shortage of infection-selective radiopharmaceuticals exists for overcoming the diagnostic limitations with unspecific tracers such as (67/68)Ga-citrate or (18)F-FDG. We report here TBIA101, an antimicrobial peptide derivative that was conjugated to DOTA and radiolabeled with (68)Ga for a subsequent in vitro assessment and in vivo infection imaging using Escherichia coli-bearing mice by targeting bacterial lipopolysaccharides with PET/CT. Following DOTA-conjugation, the compound was verified for its cytotoxic and bacterial binding behaviour and compound stability, followed by (68)Gallium-radiolabeling. µPET/CT using (68)Ga-DOTA-TBIA101 was employed to detect muscular E. coli-infection in BALB/c mice, as warranted by the in vitro results. (68)Ga-DOTA-TBIA101-PET detected E. coli-infected muscle tissue (SUV = 1.3-2.4) > noninfected thighs (P = 0.322) > forearm muscles (P = 0.092) > background (P = 0.021) in the same animal. Normalization of the infected thigh muscle to reference tissue showed a ratio of 3.0 ± 0.8 and a ratio of 2.3 ± 0.6 compared to the identical healthy tissue. The majority of the activity was cleared by renal excretion. The latter findings warrant further preclinical imaging studies of greater depth, as the DOTA-conjugation did not compromise the TBIA101's capacity as targeting vector. PMID:25699267

  12. Structural response and input identification

    NASA Technical Reports Server (NTRS)

    Shepard, G. D.; Callahan, J. C.; Mcelman, J. A.

    1981-01-01

    Three major goals were delineated: (1) to develop a general method for determining the response of a structure to combined base and acoustic random excitation: (2) to develop parametric relationships to aid in the design of plates which are subjected to random force or random base excitation: (3) to develop a method to identify the individual acoustic and base input to a structure with only a limited number of measurement channels, when both types of excitation act simultaneously.

  13. A new interpretation and validation of variance based importance measures for models with correlated inputs

    NASA Astrophysics Data System (ADS)

    Hao, Wenrui; Lu, Zhenzhou; Li, Luyi

    2013-05-01

    In order to explore the contributions by correlated input variables to the variance of the output, a novel interpretation framework of importance measure indices is proposed for a model with correlated inputs, which includes the indices of the total correlated contribution and the total uncorrelated contribution. The proposed indices accurately describe the connotations of the contributions by the correlated input to the variance of output, and they can be viewed as the complement and correction of the interpretation about the contributions by the correlated inputs presented in "Estimation of global sensitivity indices for models with dependent variables, Computer Physics Communications, 183 (2012) 937-946". Both of them contain the independent contribution by an individual input. Taking the general form of quadratic polynomial as an illustration, the total correlated contribution and the independent contribution by an individual input are derived analytically, from which the components and their origins of both contributions of correlated input can be clarified without any ambiguity. In the special case that no square term is included in the quadratic polynomial model, the total correlated contribution by the input can be further decomposed into the variance contribution related to the correlation of the input with other inputs and the independent contribution by the input itself, and the total uncorrelated contribution can be further decomposed into the independent part by interaction between the input and others and the independent part by the input itself. Numerical examples are employed and their results demonstrate that the derived analytical expressions of the variance-based importance measure are correct, and the clarification of the correlated input contribution to model output by the analytical derivation is very important for expanding the theory and solutions of uncorrelated input to those of the correlated one.

  14. Images

    Cancer.gov

    Images can be a powerful and direct means of communicating ideas and feelings about an organization and can create a personal connection with an audience. Imagery used for the main NCI website has been selected to give a consistent look throughout the site. Here are some recommended attributes for NCI website imagery.

  15. National Hospital Input Price Index

    PubMed Central

    Freeland, Mark S.; Anderson, Gerard; Schendler, Carol Ellen

    1979-01-01

    The national community hospital input price index presented here isolates the effects of prices of goods and services required to produce hospital care and measures the average percent change in prices for a fixed market basket of hospital inputs. Using the methodology described in this article, weights for various expenditure categories were estimated and proxy price variables associated with each were selected. The index is calculated for the historical period 1970 through 1978 and forecast for 1979 through 1981. During the historical period, the input price index increased an average of 8.0 percent a year, compared with an average rate of increase of 6.6 percent for overall consumer prices. For the period 1979 through 1981, the average annual increase is forecast at between 8.5 and 9.0 percent. Using the index to deflate growth in expenses, the level of real growth in expenditures per inpatient day (net service intensity growth) averaged 4.5 percent per year with considerable annual variation related to government and hospital industry policies. PMID:10309052

  16. National hospital input price index.

    PubMed

    Freeland, M S; Anderson, G; Schendler, C E

    1979-01-01

    The national community hospital input price index presented here isolates the effects of prices of goods and services required to produce hospital care and measures the average percent change in prices for a fixed market basket of hospital inputs. Using the methodology described in this article, weights for various expenditure categories were estimated and proxy price variables associated with each were selected. The index is calculated for the historical period 1970 through 1978 and forecast for 1979 through 1981. During the historical period, the input price index increased an average of 8.0 percent a year, compared with an average rate of increase of 6.6 percent for overall consumer prices. For the period 1979 through 1981, the average annual increase is forecast at between 8.5 and 9.0 per cent. Using the index to deflate growth in expenses, the level of real growth in expenditures per inpatient day (net service intensity growth) averaged 4.5 percent per year with considerable annual variation related to government and hospital industry policies. PMID:10309052

  17. Impact of remote sensing upon the planning, management and development of water resources. Summary of computers and computer growth trends for hydrologic modeling and the input of ERTS image data processing load

    NASA Technical Reports Server (NTRS)

    Castruccio, P. A.; Loats, H. L., Jr.

    1975-01-01

    An analysis of current computer usage by major water resources users was made to determine the trends of usage and costs for the principal hydrologic users/models. The laws and empirical relationships governing the growth of the data processing loads were described and applied to project the future data loads. Data loads for ERTS CCT image processing were computed and projected through the 1985 era. The analysis showns significant impact due to the utilization and processing of ERTS CCT's data.

  18. Naval threat countermeasure simulator and the IR_CRUISE_missiles models for the generation of infrared (IR) videos of maritime targets and background for input into advanced imaging IR seekers

    NASA Astrophysics Data System (ADS)

    Taczak, Thomas M.; Dries, John W.; Gover, Robert E.; Snapp, Mary Ann; Williams, Elmer F.; Cahill, Colin P.

    2002-07-01

    A new hardware-in-the-loop modeling technique was developed at the US Naval Research Laboratory (NRL) for the evaluation of IR countermeasures against advanced IR imaging anti-ship cruise missiles. The research efforts involved the creation of tools to generate accurate IR imagery and synthesize video to inject in to real-world threat simulators. A validation study was conducted to verify the accuracy and limitations of the techniques that were developed.

  19. Predicting forest structural parameters using the image texture derived from WorldView-2 multispectral imagery in a dryland forest, Israel

    NASA Astrophysics Data System (ADS)

    Ozdemir, Ibrahim; Karnieli, Arnon

    2011-10-01

    Estimation of forest structural parameters by field-based data collection methods is both expensive and time consuming. Satellite remote sensing is a low-cost alternative in modeling and mapping structural parameters in large forest areas. The current study investigates the potential of using WordView-2 multispectral satellite imagery for predicting forest structural parameters in a dryland plantation forest in Israel. The relationships between image texture features and the several structural parameters such as Number of Trees (NT), Basal Area (BA), Stem Volume (SV), Clark-Evans Index (CEI), Diameter Differentiation Index (DDI), Contagion Index (CI), Gini Coefficient (GC), and Standard Deviation of Diameters at Breast Heights (SDDBH) were examined using correlation analyses. These variables were obtained from 30 m × 30 m square-shaped plots. The Standard Deviation of Gray Levels (SDGL) as a first order texture feature and the second order texture variables based on Gray Level Co-occurrence Matrix (GLCM) were calculated for the pixels that corresponds to field plots. The results of the correlation analysis indicate that the forest structural parameters are significantly correlated with the image texture features. The highest correlation coefficients were calculated for the relationships between the SDDBH and the contrast of red band ( r = 0.75, p < 0.01), the BA and the entropy of blue band ( r = 0.73, p < 0.01), and the GC and the contrast of blue band ( r = 0.71, p < 0.01). Each forest structural parameter was modeled as a function of texture measures derived from the satellite image using stepwise multi linear regression analyses. The determination coefficient ( R2) and root mean square error (RMSE) values of the best fitting models, respectively, are 0.38 and 109.56 ha -1 for the NT; 0.54 and 1.79 m 2 ha -1 for the BA; 0.42 and 27.18 m 3 ha -1 for the SV; 0.23 and 0.16 for the CEI; 0.32 and 0.05 for the DDI; 0.25 and 0.06 for the CI; 0.50 and 0.05 for the GC; and 0.67 and 0.70 for the SDDBH. The leave-one-out cross-validation technique was applied for validation of the best-fitted models ( R2 > 0.50). In conclusion, cross-validated statistics confirmed that the structural parameters including the BA, SDDBH, and GC can be predicted and mapped with a reasonable accuracy using the texture features extracted from the spectral bands of WorldView-2 image.

  20. Guided image filtering.

    PubMed

    He, Kaiming; Sun, Jian; Tang, Xiaoou

    2013-06-01

    In this paper, we propose a novel explicit image filter called guided filter. Derived from a local linear model, the guided filter computes the filtering output by considering the content of a guidance image, which can be the input image itself or another different image. The guided filter can be used as an edge-preserving smoothing operator like the popular bilateral filter [1], but it has better behaviors near edges. The guided filter is also a more generic concept beyond smoothing: It can transfer the structures of the guidance image to the filtering output, enabling new filtering applications like dehazing and guided feathering. Moreover, the guided filter naturally has a fast and nonapproximate linear time algorithm, regardless of the kernel size and the intensity range. Currently, it is one of the fastest edge-preserving filters. Experiments show that the guided filter is both effective and efficient in a great variety of computer vision and computer graphics applications, including edge-aware smoothing, detail enhancement, HDR compression, image matting/feathering, dehazing, joint upsampling, etc. PMID:23599054

  1. High resolution radar imaging

    NASA Astrophysics Data System (ADS)

    Snyder, Donald L.

    1988-11-01

    The goal of this project is to formulate and investigate new approaches for forming images of radar targets from spotlight-mode, delay-doppler measurements. These measurements could be acquired with a high-resolution radar-imaging system operating with an optical-or radio-frequency carrier. Two approaches are under study. The first is motivated by an image-reconstruction algorithm used in radionuclide imaging called the confidence-weighted algorithm; here, we will refer to this approach as the chirp-rate modulation approach. The second approach is based on more fundamental principles which starts with a mathematical model that accurately describes the physics of an imaging radar-system and then uses statistical-estimation theory with this model to derive processing algorithms; we will refer to this as the estimation-theory approach. Progress during this reporting period has been made on: (1) extending the estimation-theory approach to include a constraint on input signal-to-noise ratio; (2) extending the estimation-theory approach to include a sieve constraint for stabilizing image estimates, (3) extending the estimation-theory approach to include a specular or glint component in the radar-echo data; (4) analyzing the performance of the estimation-theory approach through computer simulations; and (5) modifying the chirp-rate modulation approach through the introduction of the Wigner-Ville distribution. A patent was awarded associated with the chirp-rate modulation approach.

  2. Self-consistent input-output formulation of quantum feedback

    SciTech Connect

    Yanagisawa, M. [Department of Engineering, The Australian National University, Canberra, ACT 0200 (Australia); Hope, J. J. [Department of Quantum Science, The Australian National University, Canberra, ACT 0200 (Australia)

    2010-12-15

    A simple method of analyzing quantum feedback circuits is presented. The classical analysis of feedback circuits can be generalized to apply to quantum systems by mapping the field operators of various outputs to other inputs via the standard input-output formalism. Unfortunately, this has led to unphysical results such as the violation of the Heisenberg uncertainty principle for in-loop fields. This paper shows that this general approach can be redeemed by ensuring a self-consistently Hermitian Hamiltonian. The calculations are based on a noncommutative calculus of operator derivatives. A full description of several examples of quantum linear and nonlinear feedback for optical systems is presented.

  3. Improved Quantification of Cerebral Hemodynamics Using Individualized Time Thresholds for Assessment of Peak Enhancement Parameters Derived from Dynamic Susceptibility Contrast Enhanced Magnetic Resonance Imaging

    PubMed Central

    Nasel, Christian; Kalcher, Klaudius; Boubela, Roland; Moser, Ewald

    2014-01-01

    Purpose Assessment of cerebral ischemia often employs dynamic susceptibility contrast enhanced magnetic resonance imaging (DSC-MRI) with evaluation of various peak enhancement time parameters. All of these parameters use a single time threshold to judge the maximum tolerable peak enhancement delay that is supposed to reliably differentiate sufficient from critical perfusion. As the validity of this single threshold approach still remains unclear, in this study, (1) the definition of a threshold on an individual patient-basis, nevertheless (2) preserving the comparability of the data, was investigated. Methods The histogram of time-to-peak (TTP) values derived from DSC-MRI, the so-called TTP-distribution curve (TDC), was modeled using a double-Gaussian model in 61 patients without severe cerebrovascular disease. Particular model-based zf-scores were used to describe the arterial, parenchymal and venous bolus-transit phase as time intervals Ia,p,v. Their durations (delta Ia,p,v), were then considered as maximum TTP-delays of each phase. Results Mean-R2 for the model-fit was 0.967. Based on the generic zf-scores the proposed bolus transit phases could be differentiated. The Ip-interval reliably depicted the parenchymal bolus-transit phase with durations of 3.4 s–10.1 s (median?=?4.3s), where an increase with age was noted (?30 ms/year). Conclusion Individual threshold-adjustment seems rational since regular bolus-transit durations in brain parenchyma obtained from the TDC overlap considerably with recommended critical TTP-thresholds of 4 s–8 s. The parenchymal transit time derived from the proposed model may be utilized to individually correct TTP-thresholds, thereby potentially improving the detection of critical perfusion. PMID:25521121

  4. Quantitative assessment of neurite outgrowth in human embryonic stem cell-derived hN2 cells using automated high-content image analysis.

    PubMed

    Harrill, Joshua A; Freudenrich, Theresa M; Machacek, Dave W; Stice, Steven L; Mundy, William R

    2010-06-01

    Throughout development neurons undergo a number of morphological changes including neurite outgrowth from the cell body. Exposure to neurotoxic chemicals that interfere with this process may result in permanent deficits in nervous system function. Traditionally, rodent primary neural cultures and immortalized human and non-human clonal cell lines have been used to investigate the molecular mechanisms controlling neurite outgrowth and examine chemical effects on this process. The present study characterizes the molecular phenotype of hN2 human embryonic stem cell (hESC)-derived neural cells and uses automated high-content image analysis to measure neurite outgrowth in vitro. At 24h post-plating hN2 cells express a number of protein markers indicative of a neuronal phenotype, including: nestin, beta(III)-tubulin, microtubule-associated protein 2 (MAP2) and phosphorylated neurofilaments. Neurite outgrowth in hN2 cells proceeded rapidly, with a majority of cells extending one to three neurites by 48h in culture. In addition, concentration-dependent decreases in neurite outgrowth and ATP-content were observed following treatment of hN2 cells with either bisindolylmaleimide I, U0126, lithium chloride, sodium orthovanadate and brefeldin A, all of which have previously been shown to inhibit neurite outgrowth in primary rodent neural cultures. Overall, the molecular phenotype, rate of neurite outgrowth and sensitivity of hN2 cells to neurite outgrowth inhibitors were comparable to other in vitro models previously characterized in the literature. hN2 cells provide a model in which to investigate chemical effects on neurite outgrowth in a non-transformed human-derived cells and provide an alternative to the use of primary rodent neural cultures or immortalized clonal cell lines. PMID:20188755

  5. Image-Based Quantification of Benzoporphyrin Derivative Uptake, Localization, and Photobleaching in 3D Tumor Models, for Optimization of PDT Parameters

    PubMed Central

    Glidden, Michael D.; Celli, Jonathan P.; Massodi, Iqbal; Rizvi, Imran; Pogue, Brian W.; Hasan, Tayyaba

    2012-01-01

    Photodynamic therapy (PDT) is a light-based treatment modality in which wavelength specific activation of a photosensitizer (PS) generates cytotoxic response in the irradiated region. PDT response is critically dependent on several parameters including light dose, PS dose, uptake time, fluence rate, and the mode of light delivery. While the systematic optimization of these treatment parameters can be complex, it also provides multiple avenues for enhancement of PDT efficacy under diverse treatment conditions, provided that a rational framework is established to quantify the impact of parameter selection upon treatment response. Here we present a theranostic technique, combining the inherent ability of the PS to serve simultaneously as a therapeutic and imaging agent, with the use of image-based treatment assessment in three dimensional (3D) in vitro tumor models, to comprise a platform to evaluate the impact of PDT parameters on treatment outcomes. We use this approach to visualize and quantify the uptake, localization, and photobleaching of the PS benzoporphyrin derivative monoacid ring-A (BPD) in a range of treatment conditions with varying uptake times as well as continuous and fractionated light delivery regimens in 3D cultures of AsPC-1 and PANC-1 cells. Informed by photobleaching patterns and correlation with cytotoxic response, asymmetric fractionated light delivery at 4 hours BPD uptake was found to be the most effective regimen assessed. Quantification of the spatial profile of cell killing within multicellular nodules revealed that these conditions also achieve the highest depth of cytotoxicity along the radial axis of 3D nodules. The framework introduced here provides a means for systematic assessment of PDT treatment parameters in biologically relevant 3D tumor models with potential for broader application to other systems. PMID:23082096

  6. (18)F-trifluoroborate derivatives of [des-arg(10)]kallidin for imaging bradykinin b1 receptor expression with positron emission tomography.

    PubMed

    Liu, Zhibo; Amouroux, Guillaume; Zhang, Zhengxing; Pan, Jinhe; Hundal-Jabal, Navjit; Colpo, Nadine; Lau, Joseph; Perrin, David M; Bénard, François; Lin, Kuo-Shyan

    2015-03-01

    Bradykinin B1 receptor (B1R) is involved in pain and inflammation pathways and is upregulated in inflamed tissues and cancer. Due to its minimal expression in healthy tissues, B1R is an attractive target for the development of therapeutic agents to treat inflammation, chronic pain, and cancer. The goal of this study is to synthesize and compare two (18)F-labeled peptides derived from potent B1R antagonists B9858 and B9958 for imaging B1R expression with positron emission tomography (PET). Azidoacetyl-B9858 2 and azidoacetyl-B9958 3 were synthesized by a solid-phase approach and subsequently clicked to ammoniomethyl-trifluoroborate (AmBF3)-conjugated alkyne 1 to obtain AmBF3-B9858 and AmBF3-B9958, respectively. AmBF3-B9858 and AmBF3-B9958 bound B1R with high affinity, with Ki values at 0.09 ± 0.08 and 0.46 ± 0.03 nM, respectively, as measured by in vitro competition binding assays. (18)F labeling was performed via an (18)F-(19)F isotope exchange reaction. The radiofluorinated tracers were obtained within a synthesis time of 30 min and with 23-32% non-decay-corrected radiochemical yield, >99% radiochemical purity, and 43-87 GBq/?mol specific activity at the end of the synthesis. PET imaging and biodistribution studies were carried out in mice bearing both B1R-positive (B1R(+)) HEK293T::hB1R and B1R-negative (B1R(-)) HEK293T tumors. Both tracers cleared rapidly from most organs/tissues, mainly through the renal pathway. High uptake in B1R(+) tumors ((18)F-AmBF3-B9858: 3.94 ± 1.24% ID/g, tumor-to-muscle ratio 21.3 ± 4.33; (18)F-AmBF3-B9958: 4.20 ± 0.98% ID/g, tumor-to-muscle ratio 48.6 ± 10.7) was observed at 1 h postinjection. These results indicate that (18)F-AmBF3-B9858 and (18)F-AmBF3-B9958 are promising agents for the in vivo imaging of B1R expression with PET. PMID:25629412

  7. High Throughput Measurement of Ca2+ Dynamics for Drug Risk Assessment in Human Stem Cell-derived Cardiomyocytes by Kinetic Image Cytometry

    PubMed Central

    Cerignoli, Fabio; Charlot, David; Whittaker, Ross; Ingermanson, Randy; Gehalot, Piyush; Savtchenko, Alex; Gallacher, David J.; Towart, Rob; Price, Jeffrey H.; McDonough, Patrick M.; Mercola, Mark

    2013-01-01

    Current methods to measure physiological properties of cardiomyocytes and predict fatal arrhythmias that can cause sudden death, such as Torsade de Pointes, lack either the automation and throughput needed for early-stage drug discovery and/or have poor predictive value. To increase throughput and predictive power of in vitro assays, we developed kinetic imaging cytometry (KIC) for automated cell-by-cell analyses via intracellular fluorescence Ca2+ indicators. The KIC instrument simultaneously records and analyzes intracellular calcium concentration [Ca2+]i at 30-ms resolution from hundreds of individual cells/well of 96-well plates in seconds, providing kinetic details not previously possible with well averaging technologies such as plate readers. Analyses of human embryonic stem cell and induced pluripotent stem cell-derived cardiomyocytes revealed effects of known cardiotoxic and arrhythmogenic drugs on kinetic parameters of Ca2+ dynamics, suggesting that KIC will aid in the assessment of cardiotoxic risk and in the elucidation of pathogenic mechanisms of heart disease associated with drugs treatment and/or genetic background. PMID:22926323

  8. Detection and localization of novel hordatine-like compounds and glycosylated derivates of hordatines by imaging mass spectrometry of barley seeds.

    PubMed

    Gorzolka, Karin; Bednarz, Hanna; Niehaus, Karsten

    2014-06-01

    Mass spectrometry imaging was applied on germinated barley for the detailed localization of metabolites in longitudinal and transversal seed sections. Among others, 20 m/z signals occurred in three regular peak clusters with specific, distinct localizations in embryo tissues. High resolution FT-ICR MS, MALDI-TOF MS/MS, and UHPLC-ESI MS/MS served for the identification and structural characterization of these compounds. Only five metabolites were published in their structures, namely the antifungal compounds hordatine A and B in non-glycosylated and glycosylated forms. All other non-identified cluster compounds were of hordatine-like structure and differed by systematic O-methylations, hydroxylations, and glycosylations. These differences in molecular structures correlated to distinct localization patterns within the embryo and might serve for the regulation of antifungal properties. Based on the structural investigations by mass spectrometry, an array of different hordatines that comprises the five published hordatines, 15 novel hordatine derivates and their six precursors could be localized in the embryo of germinated barley. Implications for the biosynthetic pathway and transport processes are discussed. PMID:24671626

  9. Longitudinal monitoring adipose-derived stem cell survival by PET imaging hexadecyl-4-¹²?I-iodobenzoate in rat myocardial infarction model.

    PubMed

    Kim, Min Hwan; Woo, Sang-Keun; Lee, Kyo Chul; An, Gwang Il; Pandya, Darpan; Park, Noh Won; Nahm, Sang-Soep; Eom, Ki Dong; Kim, Kwang Il; Lee, Tae Sup; Kim, Chan Wha; Kang, Joo Hyun; Yoo, Jeongsoo; Lee, Yong Jin

    2015-01-01

    This study aims to monitor how the change of cell survival of transplanted adipose-derived stem cells (ADSCs) responds to myocardial infarction (MI) via the hexadecyl-4-(124)I-iodobenzoate ((124)I-HIB) mediated direct labeling method in vivo. Stem cells have shown the potential to improve cardiac function after MI. However, monitoring of the fate of transplanted stem cells at target sites is still unclear. Rat ADSCs were labeled with (124)I-HIB, and radiolabeled ADSCs were transplanted into the myocardium of normal and MI model. In the group of (124)I-HIB-labeled ADSC transplantation, in vivo imaging was performed using small-animal positron emission tomography (PET)/computed tomography (CT) for 9 days. Twenty-one days post-transplantation, histopathological analysis and apoptosis assay were performed. ADSC viability and differentiation were not affected by (124)I-HIB labeling. In vivo tracking of the (124)I-HIB-labeled ADSCs was possible for 9 and 3 days in normal and MI model, respectively. Apoptosis of transplanted cells increased in the MI model compared than that in normal model. We developed a direct labeling agent, (124)I-HIB, and first tried to longitudinally monitor transplanted stem cell to MI. This approach may provide new insights on the roles of stem cell monitoring in living bodies for stem cell therapy from pre-clinical studies to clinical trials. PMID:25446095

  10. Quantitative prediction of radio frequency induced local heating derived from measured magnetic field maps in magnetic resonance imaging: A phantom validation at 7 T

    NASA Astrophysics Data System (ADS)

    Zhang, Xiaotong; Van de Moortele, Pierre-Francois; Liu, Jiaen; Schmitter, Sebastian; He, Bin

    2014-12-01

    Electrical Properties Tomography (EPT) technique utilizes measurable radio frequency (RF) coil induced magnetic fields (B1 fields) in a Magnetic Resonance Imaging (MRI) system to quantitatively reconstruct the local electrical properties (EP) of biological tissues. Information derived from the same data set, e.g., complex numbers of B1 distribution towards electric field calculation, can be used to estimate, on a subject-specific basis, local Specific Absorption Rate (SAR). SAR plays a significant role in RF pulse design for high-field MRI applications, where maximum local tissue heating remains one of the most constraining limits. The purpose of the present work is to investigate the feasibility of such B1-based local SAR estimation, expanding on previously proposed EPT approaches. To this end, B1 calibration was obtained in a gelatin phantom at 7 T with a multi-channel transmit coil, under a particular multi-channel B1-shim setting (B1-shim I). Using this unique set of B1 calibration, local SAR distribution was subsequently predicted for B1-shim I, as well as for another B1-shim setting (B1-shim II), considering a specific set of parameter for a heating MRI protocol consisting of RF pulses plaid at 1% duty cycle. Local SAR results, which could not be directly measured with MRI, were subsequently converted into temperature change which in turn were validated against temperature changes measured by MRI Thermometry based on the proton chemical shift.

  11. Fundamentals of! Image Processing!

    E-print Network

    Erdem, Erkut

    : Hoiem! Matching with filters" · Goal: find in image! · Method 2: SSD! ! Input! 1- sqrt(SSD)! Thresholded in image! · Method 2: SSD! ! Input! 1- sqrt(SSD)! 2 , )],[],[(],[ lnkmflkgnmh lk ++-= What s the potential downside of SSD?! Slide: Hoiem! SSD sensitive to average intensity! Matching with filters" · Goal: find

  12. Fundamentals of Image Processing

    E-print Network

    Erdem, Erkut

    ;Slide: Hoiem Matching with filters · Goal: find in image · Method 2: SSD Input 1- sqrt(SSD: find in image · Method 2: SSD Input 1- sqrt(SSD) 2 , )],[],[(],[ lnkmflkgnmh lk ++-= What's the potential downside of SSD? Slide: Hoiem SSD sensitive to average intensity #12;Matching with filters

  13. On the Variability of Wind Power Input to the Oceans with a Focus on the Subpolar North Atlantic

    E-print Network

    Wunsch, Carl

    On the Variability of Wind Power Input to the Oceans with a Focus on the Subpolar North Atlantic of power inputs from winds and buoyancy exchange is complex in part because it depends upon knowing a great determined mainly by the wind field itself. The input of buoyancy- derived power has been generally regarded

  14. Modeling, analysis and design for hybrid power systems with dual-input DC\\/DC converter

    Microsoft Academic Search

    Yan Li; Xinbo Ruan; Dongsheng Yang; Fuxin Liu

    2009-01-01

    Hybrid power systems derive power simultaneously from several renewable energy sources and deliver power continuously to the load. For such systems, the use of a multiple-input converter (MIC) has the advantage of simpler circuit design and lower cost, compared to the conventional use of several single-input converters. Taking dual-input Buck converter as the example in this paper, a new power

  15. Input/output properties of the lateral vestibular nucleus

    NASA Technical Reports Server (NTRS)

    Boyle, R.; Bush, G.; Ehsanian, R.

    2004-01-01

    This article is a review of work in three species, squirrel monkey, cat, and rat studying the inputs and outputs from the lateral vestibular nucleus (LVN). Different electrophysiological shock paradigms were used to determine the synaptic inputs derived from thick to thin diameter vestibular nerve afferents. Angular and linear mechanical stimulations were used to activate and study the combined and individual contribution of inner ear organs and neck afferents. The spatio-temporal properties of LVN neurons in the decerebrated rat were studied in response to dynamic acceleration inputs using sinusoidal linear translation in the horizontal head plane. Outputs were evaluated using antidromic identification techniques and identified LVN neurons were intracellularly injected with biocytin and their morphology studied.

  16. Multiple input electrode gap controller

    DOEpatents

    Hysinger, C.L.; Beaman, J.J.; Melgaard, D.K.; Williamson, R.L.

    1999-07-27

    A method and apparatus for controlling vacuum arc remelting (VAR) furnaces by estimation of electrode gap based on a plurality of secondary estimates derived from furnace outputs. The estimation is preferably performed by Kalman filter. Adaptive gain techniques may be employed, as well as detection of process anomalies such as glows. 17 figs.

  17. 7 CFR 3430.607 - Stakeholder input.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...AWARD ADMINISTRATIVE PROVISIONS Beginning Farmer and Rancher Development Program § 3430.607 Stakeholder input. CSREES shall...g., public meetings, request for input and/or via Web site), as well as through a notice in the Federal...

  18. 7 CFR 3430.607 - Stakeholder input.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...AWARD ADMINISTRATIVE PROVISIONS Beginning Farmer and Rancher Development Program § 3430.607 Stakeholder input. CSREES shall...e.g., public meetings, request for input and/or via Web site), as well as through a notice in the Federal...

  19. 7 CFR 3430.607 - Stakeholder input.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...AWARD ADMINISTRATIVE PROVISIONS Beginning Farmer and Rancher Development Program § 3430.607 Stakeholder input. NIFA shall...e.g., public meetings, request for input and/or via Web site), as well as through a notice in the Federal...

  20. 7 CFR 3430.607 - Stakeholder input.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...AWARD ADMINISTRATIVE PROVISIONS Beginning Farmer and Rancher Development Program § 3430.607 Stakeholder input. NIFA shall...e.g., public meetings, request for input and/or via Web site), as well as through a notice in the Federal...

  1. Flight Test Validation of Optimal Input Design and Comparison to Conventional Inputs

    NASA Technical Reports Server (NTRS)

    Morelli, Eugene A.

    1997-01-01

    A technique for designing optimal inputs for aerodynamic parameter estimation was flight tested on the F-18 High Angle of Attack Research Vehicle (HARV). Model parameter accuracies calculated from flight test data were compared on an equal basis for optimal input designs and conventional inputs at the same flight condition. In spite of errors in the a priori input design models and distortions of the input form by the feedback control system, the optimal inputs increased estimated parameter accuracies compared to conventional 3-2-1-1 and doublet inputs. In addition, the tests using optimal input designs demonstrated enhanced design flexibility, allowing the optimal input design technique to use a larger input amplitude to achieve further increases in estimated parameter accuracy without departing from the desired flight test condition. This work validated the analysis used to develop the optimal input designs, and demonstrated the feasibility and practical utility of the optimal input design technique.

  2. Capacity of Power Constrained Memoryless AWGN Channels with Fixed Input Constellations

    E-print Network

    Kavcic, Aleksandar

    Capacity of Power Constrained Memoryless AWGN Channels with Fixed Input Constellations #3; Nedeljko constellation constraint and 2) a maximum power constraint. We also consider nearly optimal codes derived from

  3. 77 FR 54902 - Proposed Information Collection; Comment Request; Input From Hawaii's Boat-based Anglers

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-09-06

    ...Collection; Comment Request; Input From Hawaii's Boat-based Anglers AGENCY: National...National Data Standards. The State of Hawaii is developing a comprehensive data collection...fishing catch and effort derived from Hawaii's private boaters--a required...

  4. apART: system for the acquisition, processing, archiving, and retrieval of digital images in an open, distributed imaging environment

    NASA Astrophysics Data System (ADS)

    Schneider, Uwe; Strack, Ruediger

    1992-04-01

    apART reflects the structure of an open, distributed environment. According to the general trend in the area of imaging, network-capable, general purpose workstations with capabilities of open system image communication and image input are used. Several heterogeneous components like CCD cameras, slide scanners, and image archives can be accessed. The system is driven by an object-oriented user interface where devices (image sources and destinations), operators (derived from a commercial image processing library), and images (of different data types) are managed and presented uniformly to the user. Browsing mechanisms are used to traverse devices, operators, and images. An audit trail mechanism is offered to record interactive operations on low-resolution image derivatives. These operations are processed off-line on the original image. Thus, the processing of extremely high-resolution raster images is possible, and the performance of resolution dependent operations is enhanced significantly during interaction. An object-oriented database system (APRIL), which can be browsed, is integrated into the system. Attribute retrieval is supported by the user interface. Other essential features of the system include: implementation on top of the X Window System (X11R4) and the OSF/Motif widget set; a SUN4 general purpose workstation, inclusive ethernet, magneto optical disc, etc., as the hardware platform for the user interface; complete graphical-interactive parametrization of all operators; support of different image interchange formats (GIF, TIFF, IIF, etc.); consideration of current IPI standard activities within ISO/IEC for further refinement and extensions.

  5. MegaPipe: the MegaCam image stacking pipeline at the Canadian Astronomical Data Centre

    E-print Network

    Stephen. D. J. Gwyn

    2007-10-01

    This paper describes the MegaPipe image processing pipeline at the Canadian Astronomical Data Centre. The pipeline combines multiple images from the MegaCam mosaic camera on CFHT and combines them into a single output image. MegaPipe takes as input detrended MegaCam images and does a careful astrometric and photometric calibration on them. The calibrated images are then resampled and combined into image stacks. The astrometric calibration of the output images is accurate to within 0.15 arcseconds relative to external reference frames and 0.04 arcseconds internally. The photometric calibration is good to within 0.03 magnitudes. The stacked images and catalogues derived from these images are available through the CADC website:

  6. Input Locality and Hardness Amplification Andrej Bogdanov

    E-print Network

    Rosen, Alon

    Input Locality and Hardness Amplification Andrej Bogdanov Alon Rosen Abstract We establish new hardness amplification results for one-way functions in which each input bit influences only a small number is injective then it is equally hard to invert f on a (1 - )-fraction of inputs. · If f is regular

  7. Single-Electron Devices With Input Discretizer

    Microsoft Academic Search

    Yoshinao Mizugaki; Masashi Takiguchi; Shota Hayami; Akio Kawai; Masataka Moriya; Kouichi Usami; Tadayuki Kobayashi; Hiroshi Shimada

    2008-01-01

    We propose an input discretizer for single-electron (SE) devices. The input discretizer is composed of one small tunnel junction and two capacitances. Adjusting the capacitances to be equal discretizes the gate charge with interval of a half of the elementary charge e, which enhances the performance of SE devices. An SE transistor with the input discretizer has abrupt switchings of

  8. Input filter compensation for switching regulators

    NASA Technical Reports Server (NTRS)

    Lee, F. C.

    1984-01-01

    Problems caused by input filter interaction and conventional input filter design techniques are discussed. The concept of feedforward control is modeled with an input filter and a buck regulator. Experimental measurement and comparison to the analytical predictions is carried out. Transient response and the use of a feedforward loop to stabilize the regulator system is described. Other possible applications for feedforward control are included.

  9. Effects of Auditory Input in Individuation Tasks

    ERIC Educational Resources Information Center

    Robinson, Christopher W.; Sloutsky, Vladimir M.

    2008-01-01

    Under many conditions auditory input interferes with visual processing, especially early in development. These interference effects are often more pronounced when the auditory input is unfamiliar than when the auditory input is familiar (e.g. human speech, pre-familiarized sounds, etc.). The current study extends this research by examining how…

  10. Textual Enhancement of Input: Issues and Possibilities

    ERIC Educational Resources Information Center

    Han, ZhaoHong; Park, Eun Sung; Combs, Charles

    2008-01-01

    The input enhancement hypothesis proposed by Sharwood Smith (1991, 1993) has stimulated considerable research over the last 15 years. This article reviews the research on textual enhancement of input (TE), an area where the majority of input enhancement studies have aggregated. Methodological idiosyncrasies are the norm of this body of research.…

  11. Input Decimation Ensembles: Decorrelation through Dimensionality Reduction

    E-print Network

    Tumer, Kagan

    Input Decimation Ensembles: Decorrelation through Dimensionality Reduction Nikunj C. Oza1 and Kagan' performance levels high is a promising research topic. In this paper, we describe input decimation, a method [15], we showed the theoretical benefits of input decimation and presented its application

  12. Synthesis and preclinical evaluation of a new C-6 alkylated pyrimidine derivative as a PET imaging agent for HSV1-tk gene expression

    PubMed Central

    Müller, Ursina; Ross, Tobias L; Ranadheera, Charlene; Slavik, Roger; Müller, Adrienne; Born, Mariana; Trauffer, Evelyn; Sephton, Selena Milicevic; Scapozza, Leonardo; Krämer, Stefanie D; Ametamey, Simon M

    2013-01-01

    [18F]FHOMP (6-((1-[18F]-fluoro-3-hydroxypropan-2-yloxy)methyl)-5-methylpyrimidine-2,4(1H,3H)-dione), a C-6 substituted pyrimidine derivative, has been synthesized and evaluated as a potential PET agent for imaging herpes simplex virus type 1 thymidine kinase (HSV1-tk) gene expression. [18F]FHOMP was prepared by the reaction of the tosylated precursor with tetrabutylammonium [18F]-fluoride followed by acidic cleavage of the protecting groups. In vitro cell accumulation of [18F]FHOMP and [18F]FHBG (reference) was studied with HSV1-tk transfected HEK293 (HEK293TK+) cells. Small animal PET and biodistribution studies were performed with HEK293TK+ xenograft-bearing nude mice. The role of equilibrative nucleoside transporter 1 (ENT1) in the transport and uptake of [18F] FHOMP was also examined in nude mice after treatment with ENT1 inhibitor nitrobenzylmercaptopurine ribonucleoside phosphate (NBMPR-P). [18F]FHOMP was obtained in a radiochemical yield of ~25% (decay corrected) and the radiochemical purity was greater than 95%. The uptake of [18F]FHOMP in HSV1-TK containing HEK293TK+ cells was 52 times (at 30 min) and 244 times (at 180 min) higher than in control HEK293 cells. The uptake ratios between HEK293TK+ and HEK293 control cells for [18F]FHBG were significantly lower i.e. 5 (at 30 min) and 81 (240 min). In vivo, [18F]FHOMP accumulated to a similar extend in HEK293TK+ xenografts as [18F]FHBG but with a higher general background. Blocking of ENT1 reduced [18F]FHOMP uptake into brain from a standardized uptake value (SUV) of 0.10±0.01 to 0.06±0.02, but did not reduce the general background signal in PET. Although [18F]FHOMP does not outperform [18F]FHBG in its in vivo performance, this novel C-6 pyrimidine derivative may be a useful probe for monitoring HSV1-tk gene expression in vivo. PMID:23342302

  13. Tetraamine-derived bifunctional chelators for technetium-99m labelling: synthesis, bioconjugation and evaluation as targeted SPECT imaging probes for GRP-receptor-positive tumours.

    PubMed

    Abiraj, Keelara; Mansi, Rosalba; Tamma, Maria-Luisa; Forrer, Flavio; Cescato, Renzo; Reubi, Jean Claude; Akyel, Kayhan G; Maecke, Helmut R

    2010-02-15

    Owing to its optimal nuclear properties, ready availability, low cost and favourable dosimetry, (99m)Tc continues to be the ideal radioisotope for medical-imaging applications. Bifunctional chelators based on a tetraamine framework exhibit facile complexation with Tc(V)O(2) to form monocationic species with high in vivo stability and significant hydrophilicity, which leads to favourable pharmacokinetics. The synthesis of a series of 1,4,8,11-tetraazaundecane derivatives (01-06) containing different functional groups at the 6-position for the conjugation of biomolecules and subsequent labelling with (99m)Tc is described herein. The chelator 01 was used as a starting material for the facile synthesis of chelators functionalised with OH (02), N(3) (04) and O-succinyl ester (05) groups. A straightforward and easy synthesis of carboxyl-functionalised tetraamine-based chelator 06 was achieved by using inexpensive and commercially available starting materials. Conjugation of 06 to a potent bombesin-antagonist peptide and subsequent labelling with (99m)Tc afforded the radiotracer (99m)Tc-N4-BB-ANT, with radiolabelling yields of >97% at a specific activity of 37 GBq micromol(-1). An IC(50) value of (3.7+/-1.3) nM was obtained, which confirmed the high affinity of the conjugate to the gastrin-releasing-peptide receptor (GRPr). Immunofluorescence and calcium mobilisation assays confirmed the strong antagonist properties of the conjugate. In vivo pharmacokinetic studies of (99m)Tc-N4-BB-ANT showed high and specific uptake in PC3 xenografts and in other GRPr-positive organs. The tumour uptake was (22.5+/-2.6)% injected activity per gram (% IA g(-1)) at 1 h post injection (p.i.). and increased to (29.9+/-4.0)% IA g(-1) at 4 h p.i. The SPECT/computed tomography (CT) images showed high tumour uptake, clear background and negligible radioactivity in the abdomen. The promising preclinical results of (99m)Tc-N4-BB-ANT warrant its potential candidature for clinical translation. PMID:20066690

  14. Derivatives Page

    NSDL National Science Digital Library

    Derivatives are financial securities whose value is derived from another "underlying" financial security. Options, futures, swaps, swaptions, and structured notes are all examples of derivative securities. Derivatives can be used in hedging, protecting against financial risk, or can be used to speculate on the movement of commodity or security prices, interest rates, or the levels of financial indices. The valuation of derivatives makes use of the statistical mathematics of uncertainty. With links to related articles. See also Derivatives Concepts A-Z, glossary of derivatives-related terminology designed to make the other articles in the Financial Pipeline's Derivatives section easier to understand.

  15. Analytical derivation of distortion constraints and their verification in a learning vector quantization-based target recognition system

    NASA Astrophysics Data System (ADS)

    Iftekharuddin, Khan M.; Razzaque, Mohammad A.

    2005-06-01

    We obtain a novel analytical derivation for distortion-related constraints in a neural network- (NN)-based automatic target recognition (ATR) system. We obtain two types of constraints for a realistic ATR system implementation involving 4-f correlator architecture. The first constraint determines the relative size between the input objects and input correlation filters. The second constraint dictates the limits on amount of rotation, translation, and scale of input objects for system implementation. We exploit these constraints in recognition of targets varying in rotation, translation, scale, occlusion, and the combination of all of these distortions using a learning vector quantization (LVQ) NN. We present the simulation verification of the constraints using both the gray-scale images and Defense Advanced Research Projects Agency's (DARPA's) Moving and Stationary Target Recognition (MSTAR) synthetic aperture radar (SAR) images with different depression and pose angles.

  16. The response of gross nitrogen mineralization to labile carbon inputs

    NASA Astrophysics Data System (ADS)

    Bengtson, Per

    2014-05-01

    Input of labile carbon sources to forest soils commonly result in priming, i.e. an increase in the microbial decomposition of soil organic matter. Efforts aimed at quantifying the extent of priming have, to date, largely focused on soil organic matter decomposition manifested as soil respiration. Less is known about how gross nitrogen mineralization responds to input of labile carbon. It is often assumed that increased priming results in decreased soil carbon stocks. However, microbial mineralization of organic nitrogen into plant available forms is a major factor limiting primary production in forests. If increased decomposition of soil organic matter in response to labile carbon is accompanied by a concurrent increased nitrogen mineralization, this could result in elevated primary production and higher rates of plant derived organic matter input to soils. Therefore, in order to fully understand the effect of priming on net ecosystem exchange and soil carbon stocks, it is vital to consider if increased decomposition of soil organic matter caused by priming also results in increased nitrogen mineralization. Here I present the results from a series of experiments aimed at determining if, and to which extent, gross nitrogen mineralization is stimulated by input of labile carbon. The results suggest that it is by no means uncommon to find an increase in gross N mineralization rates in response to labile carbon inputs. The magnitude of the increase seems dependent on the nitrogen status of the soil, as well as the concentration and rate of labile carbon inputs. However, continuous input of labile carbon sources that also contains nitrogen, e.g. amino acids, seems to inhibit rather than increase the mineralization of organic nitrogen. These findings suggest that there is a potential for a positive feedback between priming and primary production that needs to be considered in order to fully understand the influence of priming on net ecosystem exchange and soil carbon stocks.

  17. Programmable remapper for image processing

    NASA Technical Reports Server (NTRS)

    Juday, Richard D. (inventor); Sampsell, Jeffrey B. (inventor)

    1991-01-01

    A video-rate coordinate remapper includes a memory for storing a plurality of transformations on look-up tables for remapping input images from one coordinate system to another. Such transformations are operator selectable. The remapper includes a collective processor by which certain input pixels of an input image are transformed to a portion of the output image in a many-to-one relationship. The remapper includes an interpolative processor by which the remaining input pixels of the input image are transformed to another portion of the output image in a one-to-many relationship. The invention includes certain specific transforms for creating output images useful for certain defects of visually impaired people. The invention also includes means for shifting input pixels and means for scrolling the output matrix.

  18. Labeling Human Embryonic Stem Cell-Derived Cardiomyocytes With Indocyanine Green for Noninvasive Tracking With Optical Imaging: An FDA-Compatible Alternative to Firefly Luciferase

    PubMed Central

    Boddington, Sophie E.; Henning, Tobias D.; Jha, Priyanka; Schlieve, Christopher R.; Mandrussow, Lydia; DeNardo, David; Bernstein, Harold S.; Ritner, Carissa; Golovko, Daniel; Lu, Ying; Zhao, Shoujun; Daldrup-Link, Heike E.

    2010-01-01

    Human embryonic stem cell-derived cardiomyocytes (hESC-CMs) have demonstrated the ability to improve myocardial function following transplantation into an ischemic heart; however, the functional benefits are transient possibly due to poor cell retention. A diagnostic technique that could visualize transplanted hESC-CMs could help to optimize stem cell delivery techniques. Thus, the purpose of this study was to develop a labeling technique for hESCs and hESC-CMs with the FDA-approved contrast agent indocyanine green (ICG) for optical imaging (OI). hESCs were labeled with 0.5, 1.0, 2.0, and 2.5 mg/ml of ICG for 30, 45, and 60 min at 37°C. Longitudinal OI studies were performed with both hESCs and hESC-CMs. The expression of surface proteins was assessed with immunofluorescent staining. hESCs labeled with 2 mg ICG/ml for 60 min achieved maximum fluorescence. Longitudinal studies revealed that the fluorescent signal was equivalent to controls at 120 h postlabeling. The fluorescence signal of hESCs and hESC-CMs at 1, 24, and 48 h was significantly higher compared to precontrast data (p < 0.05). Immunocytochemistry revealed retention of cell-specific surface and nuclear markers postlabeling. These data demonstrate that hESCs and hESC-CMs labeled with ICG show a significant fluorescence up to 48 h and can be visualized with OI. The labeling procedure does not impair the viability or functional integrity of the cells. The technique may be useful for assessing different delivery routes in order to improve the engraftment of transplanted hESC-CMs or other stem cell progenitors. PMID:20370988

  19. Honeybee navigation: odometry with monocular input.

    PubMed

    Srinivasan; Zhang; Lehrer

    1998-11-01

    Recent studies have revealed that navigating honeybees, Apis mellifera, estimate the distance to a food source by integrating over time the image motion that they experience en route. Here we examine the ability of honeybees to gauge distance travelled when visual input is available primarily to one eye. Bees were trained to fly into a tunnel, lined with textured patterns, to collect a reward at a feeder placed at a certain distance. Their ability to estimate distance flown was then assessed by testing them in a fresh tunnel without the feeder. The results show that (1) bees can estimate distance flown under monocular conditions, performing nearly as accurately as when information is available to both eyes; (2) bees can learn to fly two different distances, where each distance is measured in terms of the image motion experienced by a different eye; and (3) bees that have acquired information on the distance to a food source using one eye can measure out the same distance when they are required to use the other (naive) eye. The need to measure distance using signals from a single eye becomes important when a bee flies to a food source along the face of a cliff or the edge of a forest. Furthermore, under such conditions, it is important to be able to deal with odometric signals that are transposed interocularly when the bee returns home from the food source. This is because, although distances are learnt primarily on the way to a food source, foraging bees monitor distance flown on the homebound as well as the outbound routes. Copyright 1998 The Association for the Study of Animal Behaviour. PMID:9819342

  20. Correcting saturation effects of the arterial input function in dynamic susceptibility contrast-enhanced MRI: a Monte Carlo simulation.

    PubMed

    Brunecker, Peter; Villringer, Arno; Schultze, Jörg; Nolte, Christian H; Jungehülsing, Gerhard Jan; Endres, Matthias; Steinbrink, Jens

    2007-11-01

    To prevent systematic errors in quantitative brain perfusion studies using dynamic susceptibility contrast-enhanced magnetic resonance imaging (DSC-MRI), a reliable determination of the arterial input function (AIF) is essential. We propose a novel algorithm for correcting distortions of the AIF caused by saturation of the peak amplitude and discuss its relevance for longitudinal studies. The algorithm is based on the assumption that the AIF can be separated into a reliable part at low contrast agent concentrations and an unreliable part at high concentrations. This unreliable part is reconstructed, applying a theoretical framework based on a transport-diffusion theory and using the bolus-shape in the tissue. A validation of the correction scheme is tested by a Monte Carlo simulation. The input of the simulation was a wide range of perfusion, and the main aim was to compare this input to the determined perfusion parameters. Another input of the simulation was an AIF template derived from in vivo measurements. The distortions of this template was modeled via a Rician distribution for image intensities. As for a real DSC-MRI experiment, the simulation returned the AIF and the tracer concentration-dependent signal in the tissue. The novel correction scheme was tested by deriving perfusion parameters from the simulated data for the corrected and the uncorrected case. For this analysis, a common truncated singular value decomposition approach was applied. We find that the saturation effect caused by Rician-distributed noise leads to an overestimation of regional cerebral blood flow and regional cerebral blood volume, as compared to the input parameter. The aberration can be amplified by a decreasing signal-to-noise ratio (SNR) or an increasing tracer concentration. We also find that the overestimation can be successfully eliminated by the proposed saturation-correction scheme. In summary, the correction scheme will allow DSC-MRI to be expanded towards higher tracer concentrations and lower SNR and will help to increase the measurement to measurement reproducibility for longitudinal studies. PMID:17462846

  1. A Comparison Between Tilt-input and Facial Tracking as Input Methods for Mobile Games

    E-print Network

    MacKenzie, Scott

    -in accelerometer [5]. Some games, such as Imangi Studios' Temple Run, an infinite-runner game, effectively use tilt-input while also relying on touch-based input. 1 http://en.wikipedia.org/wiki/Snake_(video_game) Fig. 1. SegaA Comparison Between Tilt-input and Facial Tracking as Input Methods for Mobile Games Justin

  2. Turn customer input into innovation.

    PubMed

    Ulwick, Anthony W

    2002-01-01

    It's difficult to find a company these days that doesn't strive to be customer-driven. Too bad, then, that most companies go about the process of listening to customers all wrong--so wrong, in fact, that they undermine innovation and, ultimately, the bottom line. What usually happens is this: Companies ask their customers what they want. Customers offer solutions in the form of products or services. Companies then deliver these tangibles, and customers just don't buy. The reason is simple--customers aren't expert or informed enough to come up with solutions. That's what your R&D team is for. Rather, customers should be asked only for outcomes--what they want a new product or service to do for them. The form the solutions take should be up to you, and you alone. Using Cordis Corporation as an example, this article describes, in fine detail, a series of effective steps for capturing, analyzing, and utilizing customer input. First come indepth interviews, in which a moderator works with customers to deconstruct a process or activity in order to unearth "desired outcomes." Addressing participants' comments one at a time, the moderator rephrases them to be both unambiguous and measurable. Once the interviews are complete, researchers then compile a comprehensive list of outcomes that participants rank in order of importance and degree to which they are satisfied by existing products. Finally, using a simple mathematical formula called the "opportunity calculation," researchers can learn the relative attractiveness of key opportunity areas. These data can be used to uncover opportunities for product development, to properly segment markets, and to conduct competitive analysis. PMID:12964470

  3. PREVIMER : Meteorological inputs and outputs

    NASA Astrophysics Data System (ADS)

    Ravenel, H.; Lecornu, F.; Kerléguer, L.

    2009-09-01

    PREVIMER is a pre-operational system aiming to provide a wide range of users, from private individuals to professionals, with short-term forecasts about the coastal environment along the French coastlines bordering the English Channel, the Atlantic Ocean, and the Mediterranean Sea. Observation data and digital modelling tools first provide 48-hour (probably 96-hour by summer 2009) forecasts of sea states, currents, sea water levels and temperatures. The follow-up of an increasing number of biological parameters will, in time, complete this overview of coastal environment. Working in partnership with the French Naval Hydrographic and Oceanographic Service (Service Hydrographique et Océanographique de la Marine, SHOM), the French National Weather Service (Météo-France), the French public science and technology research institute (Institut de Recherche pour le Développement, IRD), the European Institute of Marine Studies (Institut Universitaire Européen de la Mer, IUEM) and many others, IFREMER (the French public institute fo marine research) is supplying the technologies needed to ensure this pertinent information, available daily on Internet at http://www.previmer.org, and stored at the Operational Coastal Oceanographic Data Centre. Since 2006, PREVIMER publishes the results of demonstrators assigned to limited geographic areas and to specific applications. This system remains experimental. The following topics are covered : Hydrodynamic circulation, sea states, follow-up of passive tracers, conservative or non-conservative (specifically of microbiological origin), biogeochemical state, primary production. Lastly, PREVIMER provides researchers and R&D departments with modelling tools and access to the database, in which the observation data and the modelling results are stored, to undertake environmental studies on new sites. The communication will focus on meteorological inputs to and outputs from PREVIMER. It will draw the lessons from almost 3 years during which the system has been operational almost everyday and propose perspectives in terms of technical improvements and possible business models.

  4. Gradient echo plural contrast imaging--signal model and derived contrasts: T2*, T1, phase, SWI, T1f, FST2*and T2*-SWI.

    PubMed

    Luo, Jie; Jagadeesan, Bharathi D; Cross, Anne H; Yablonskiy, Dmitriy A

    2012-04-01

    Gradient Echo Plural Contrast Imaging (GEPCI) is a post processing technique that, based on a widely available multiple gradient echo sequence, allows simultaneous generation of naturally co-registered images with various contrasts: T1 weighted, R2*=1/T2* maps and frequency (f) maps. Herein, we present results demonstrating the capability of GEPCI technique to generate image sets with additional contrast characteristics obtained by combing the information from these three basic contrast maps. Specifically, we report its ability to generate GEPCI-susceptibility weighted images (GEPCI-SWI) with improved SWI contrast that is free of T1 weighting and RF inhomogeneities; GEPCI-SWI-like images with the contrast similar to original SWI; T1f images that offer superior GM/WM matter contrast obtained by combining the GEPCI T1 and frequency map data; Fluid Suppressed T2* (FST2*) images that utilize GEPCI T1 data to suppress CSF signal in T2* maps and provide contrast similar to FLAIR T2 weighted images; and T2*-SWI images that combine SWI contrast with quantitative T2* map and offer advantages of visualizing venous structure with hyperintense T2* lesions (e.g. MS lesions). To analyze GEPCI images we use an improved algorithm for combining data from multi-channel RF coils and a method for unwrapping phase/frequency maps that takes advantage of the information on phase evolution as a function of gradient echo time in GEPCI echo train. PMID:22305993

  5. Recognition and Age Prediction with Digital Images of Missing Children

    E-print Network

    Pollett, Chris

    by 100 pixels) Assign 200 female pairs as training images Assign 150 male pairs as training images Separately reconstruct remaining female and male input images Example training image Example input images #12Recognition and Age Prediction with Digital Images of Missing Children By Wallun Chan Advisor: Dr

  6. Single-image superresolution based on local regression and nonlocal self-similarity

    NASA Astrophysics Data System (ADS)

    Hu, Jing; Luo, Yupin

    2014-05-01

    The challenge of learning-based superresolution (SR) is to predict the relationships between low-resolution (LR) patches and their corresponding high-resolution (HR) patches. By learning such relationships from external training images, the existing learning-based SR approaches are often affected by the relevance between the training data and the LR input image. Therefore, we propose a single-image SR method that learns the LR-HR relations from the given LR image itself instead of any external images. Both the local regression model and nonlocal patch redundancy are exploited in the proposed method. The local regression model is employed to derive the mapping functions between self-LR-HR example patches, and the nonlocal self-similarity gives rise to a high-order derivative estimation of the derived mapping function. Moreover, to fully exploit the multiscale similarities inside the LR input image, we accumulate the previous reconstruction results and their corresponding LR versions as additional example patches for the subsequent estimation process, and adopt a gradual magnification scheme to achieve the desired zooming size step by step. Extensive experiments on benchmark images have validated the effectiveness of the proposed method. Compared to other state-of-the-art SR approaches, the proposed method provides photorealistic HR images with sharp edges.

  7. Evaluation of limited blood sampling population input approaches for kinetic quantification of [18F]fluorothymidine PET data

    PubMed Central

    2012-01-01

    Background Quantification of kinetic parameters of positron emission tomography (PET) imaging agents normally requires collecting arterial blood samples which is inconvenient for patients and difficult to implement in routine clinical practice. The aim of this study was to investigate whether a population-based input function (POP-IF) reliant on only a few individual discrete samples allows accurate estimates of tumour proliferation using [18F]fluorothymidine (FLT). Methods Thirty-six historical FLT-PET data with concurrent arterial sampling were available for this study. A population average of baseline scans blood data was constructed using leave-one-out cross-validation for each scan and used in conjunction with individual blood samples. Three limited sampling protocols were investigated including, respectively, only seven (POP-IF7), five (POP-IF5) and three (POP-IF3) discrete samples of the historical dataset. Additionally, using the three-point protocol, we derived a POP-IF3M, the only input function which was not corrected for the fraction of radiolabelled metabolites present in blood. The kinetic parameter for net FLT retention at steady state, Ki, was derived using the modified Patlak plot and compared with the original full arterial set for validation. Results Small percentage differences in the area under the curve between all the POP-IFs and full arterial sampling IF was found over 60 min (4.2%-5.7%), while there were, as expected, larger differences in the peak position and peak height. A high correlation between Ki values calculated using the original arterial input function and all the population-derived IFs was observed (R2 = 0.85-0.98). The population-based input showed good intra-subject reproducibility of Ki values (R2 = 0.81-0.94) and good correlation (R2 = 0.60-0.85) with Ki-67. Conclusions Input functions generated using these simplified protocols over scan duration of 60 min estimate net PET-FLT retention with reasonable accuracy. PMID:22444834

  8. Input estimation from measured structural response

    SciTech Connect

    Harvey, Dustin [Los Alamos National Laboratory; Cross, Elizabeth [Los Alamos National Laboratory; Silva, Ramon A [Los Alamos National Laboratory; Farrar, Charles R [Los Alamos National Laboratory; Bement, Matt [Los Alamos National Laboratory

    2009-01-01

    This report will focus on the estimation of unmeasured dynamic inputs to a structure given a numerical model of the structure and measured response acquired at discrete locations. While the estimation of inputs has not received as much attention historically as state estimation, there are many applications where an improved understanding of the immeasurable input to a structure is vital (e.g. validating temporally varying and spatially-varying load models for large structures such as buildings and ships). In this paper, the introduction contains a brief summary of previous input estimation studies. Next, an adjoint-based optimization method is used to estimate dynamic inputs to two experimental structures. The technique is evaluated in simulation and with experimental data both on a cantilever beam and on a three-story frame structure. The performance and limitations of the adjoint-based input estimation technique are discussed.

  9. Input filter compensation for switching regulators

    NASA Technical Reports Server (NTRS)

    Lee, F. C.; Kelkar, S. S.

    1982-01-01

    The problems caused by the interaction between the input filter, output filter, and the control loop are discussed. The input filter design is made more complicated because of the need to avoid performance degradation and also stay within the weight and loss limitations. Conventional input filter design techniques are then dicussed. The concept of pole zero cancellation is reviewed; this concept is the basis for an approach to control the peaking of the output impedance of the input filter and thus mitigate some of the problems caused by the input filter. The proposed approach for control of the peaking of the output impedance of the input filter is to use a feedforward loop working in conjunction with feedback loops, thus forming a total state control scheme. The design of the feedforward loop for a buck regulator is described. A possible implementation of the feedforward loop design is suggested.

  10. Tracking of In-111-labeled human umbilical tissue-derived cells (hUTC) in a rat model of cerebral ischemia using SPECT imaging

    PubMed Central

    2012-01-01

    Background In order to increase understanding of how infused cells work, it becomes important to track their initial movement, localization, and engraftment efficiency following transplantation. However, the available in vivo cell tracking techniques are suboptimal. The study objective was to determine the biodistribution of intravenously administered Indium-111 (In-111) oxine labeled human umbilical tissue-derived cells (hUTC) in a rat model of transient middle cerebral occlusion (tMCAo) using single photon emission computed tomography (SPECT). Methods Rats received 3 million In-111 labeled hUTC (i.v.) 48?hrs after tMCAo. Following the administration of either hUTC or equivalent dose of In-111-oxine (18.5?MBq), animals underwent SPECT imaging on days 0, 1, and 3. Radioactivity in various organs as well as in the stroke area and contralateral hemisphere was determined, decay corrected and normalized to the total (whole body including head) radioactivity on day 0. Immunohistochemical analysis was also performed to confirm the beneficial effects of hUTC on vascular and synaptic density, and apoptosis. Results Most of the radioactivity (43.36±23.07% on day 0) trafficked to the lungs immediately following IV administration of In-111 labeled hUTC (day 0) and decreased drastically to 8.81±7.75 and 4.01±4.52% on days 1 and 3 post-injection, respectively. In contrast, radioactivity measured in the lung of animals that received In-111-oxine alone remained relatively unchanged from day 0 to day 1 (18.38±5.45% at day 0 to 12.59±5.94%) and decreased to 8.34±4.25% on day 3. Significantly higher radioactivity was observed in stroke areas of animals that received In-111 labeled hUTC indicating the presence of cells at the site of injury representing approximately 1% of total administered dose. In addition, there was significant increase in vascular and synaptophysin immunoreactivity in stroke areas of rats that received In-111 labeled hUTC. Conclusions The present studies showed the tracking of In-111 labeled hUTC to the sites of stroke in a rat model of tMCAo using SPECT. Animals treated with In-111 labeled hUTC showed histological improvements, with higher vascular and synaptic densities observed in the ischemic boundary zone (IBZ). PMID:23217090

  11. High-performance optical input servovalve

    NASA Astrophysics Data System (ADS)

    Harrington, Carlos E.

    1995-05-01

    In support of the Fly-by-Light Advanced Systems Hardware (FLASH) Program, Moog has developed and continues to refine a high performance optical input servovalve. This servovalve features no external electrical connections, with all control inputs commanding the valve via an optical fiber. This valve has already demonstrated dynamic and static performance that exceeds most aerospace servovalve requirements, requiring less than 100 milliwatts of optical input power.

  12. Software for device-independent graphical input

    SciTech Connect

    Hamlin, G.

    1982-01-01

    A three-level model and a graphics software structure based on the model that was developed with the goal of making graphical applications independent of the input devices are described. The software structure makes graphical applications independent of the input devices in a manner similar to the way the SIGGRAPH CORE proposal makes them independent of the output devices. A second goal was to provide a convenient means for application programmers to specify the user-input language for their applications. The software consists of an input handler and a table-driven parser. The input handler manages a CORE-like event queue, changing input events into terminal symbols and making their terminal symbols available to the parser in a uniform manner. It also removes most device dependencies. The parser is table driven from a Backus-Naur form (BNF) grammer that specifies the user-input language. The lower level grammar rules remove the remaining device dependencies from the input, and the higher level grammar rules specify legal sentences in the user-input language. Implementation of this software is on a table-top minicomputer. Experience with retrofitting existing applications indicates that one can find a grammar that removes essentially all the device dependencies from the application proper.

  13. Generation of RTL verification input stimulus

    E-print Network

    Selvarathinam, Anand Manivannan

    2001-01-01

    ) commercial tools have been developed for generating input vectors at the gate-level. This research uses a conventional ATPG tool Atalanta for gate-level input vector generation. This tool is based on FAN (fan-out-oriented test generation algorithm) [8...]. The algorithm is shown to be faster and more efficient than earlier algorithms for generating input vectors. Atalanta tool has the capability to generate exhaustive input vectors for the target gate? level design. The tests are obtained based on the stuck...

  14. Quantitative assessment of multiple sclerosis lesion load using CAD and expert input

    NASA Astrophysics Data System (ADS)

    Gertych, Arkadiusz; Wong, Alexis; Sangnil, Alan; Liu, Brent J.

    2008-03-01

    Multiple sclerosis (MS) is a frequently encountered neurological disease with a progressive but variable course affecting the central nervous system. Outline-based lesion quantification in the assessment of lesion load (LL) performed on magnetic resonance (MR) images is clinically useful and provides information about the development and change reflecting overall disease burden. Methods of LL assessment that rely on human input are tedious, have higher intra- and inter-observer variability and are more time-consuming than computerized automatic (CAD) techniques. At present it seems that methods based on human lesion identification preceded by non-interactive outlining by CAD are the best LL quantification strategies. We have developed a CAD that automatically quantifies MS lesions, displays 3-D lesion map and appends radiological findings to original images according to current DICOM standard. CAD is also capable to display and track changes and make comparison between patient's separate MRI studies to determine disease progression. The findings are exported to a separate imaging tool for review and final approval by expert. Capturing and standardized archiving of manual contours is also implemented. Similarity coefficients calculated from quantities of LL in collected exams show a good correlation of CAD-derived results vs. those incorporated as expert's reading. Combining the CAD approach with an expert interaction may impact to the diagnostic work-up of MS patients because of improved reproducibility in LL assessment and reduced time for single MR or comparative exams reading. Inclusion of CAD-generated outlines as DICOM-compliant overlays into the image data can serve as a better reference in MS progression tracking.

  15. PET Analysis Challenging Problems in PET Imaging

    E-print Network

    Renaut, Rosemary

    PET Analysis Challenging Problems in PET Imaging Estimating the Input Function for a Human Brain here on the input function step Aspen December 2004 ­ p.7 #12;PET Analysis Representative input22 = 30m. Aspen December 2004 ­ p.8 #12;PET Analysis Measured Input Function­Arterial Blood Samples 0

  16. Fingerprint Image Enhancement: Algorithm and Performance Evaluation

    Microsoft Academic Search

    Lin Hong; Yifei Wan; Anil K. Jain

    1998-01-01

    A critical step in automatic fingerprint matching is to automatically and reliably extract minutiae from the input fingerprint images. However, the performance of a minutiae extraction algorithm relies heavily on the quality of the input fingerprint images. In order to ensure that the performance of an automatic fingerprint identification\\/verification system will be robust with respect to the quality of input

  17. EDP Applications to Musical Bibliography: Input Considerations

    ERIC Educational Resources Information Center

    Robbins, Donald C.

    1972-01-01

    The application of Electronic Data Processing (EDP) has been a boon in the analysis and bibliographic control of music. However, an extra step of encoding must be undertaken for input of music. The best hope to facilitate musical input is the development of an Optical Character Recognition (OCR) music-reading machine. (29 references) (Author/NH)

  18. Supporting Incremental Join Queries on Ranked Inputs

    Microsoft Academic Search

    Apostol Natsev; Yuan-chi Chang; John R. Smith; Chung-sheng Li; Jeffrey Scott Vitter

    2001-01-01

    This paper investigates the problem of incremen- tal joins of multiple ranked data sets when the join condition is a list of arbitrary user-defined predi- cates on the input tuples. This problem arises in many important applications dealing with ordered inputs and multiple ranked data sets, and requiring the top solutions. We use multimedia applica- tions as the motivating examples

  19. The design space of input devices

    Microsoft Academic Search

    Stuart K. Card; Jock D. Mackinlay; George G. Robertson

    1990-01-01

    A bewildering variety of devices for communication from humans to computers now exists on the market. In order to make sense of this variety, and to aid in the design of new input devices, we propose a framework for describing and analyzing input devices. Following Mackinlay's semantic analysis of the design space for graphical presentations, our goal is to provide

  20. Mercury inputs into the Amazon Region, Brazil

    Microsoft Academic Search

    W. C. Pfeiffer; L. Drude de Lacerda

    1988-01-01

    Mercury inputs into the Brazilian Amazon ecosystem due to goldmining activities are quantified based on data from various Brazilian Mineral and Environmental Agencies as well as field works. Total losses of Hg were estimated to be 1.32 kg Hg\\/kg Au from which 45% are released into rivers and 55% into the atmosphere. Total Hg input to the Amazon may contribute

  1. High-performance optical input servovalve

    Microsoft Academic Search

    Carlos Harrington

    1995-01-01

    In support of the Fly-by-Light Advanced Systems Hardware (FLASH) Program, Moog has developed and continues to refine a high performance optical input servovalve. This servovalve features no external electrical connections, with all control inputs commanding the valve via an optical fiber. This valve has already demonstrated dynamic and static performance that exceeds most aerospace servovalve requirements, requiring less than 100

  2. Computing Functions by Approximating the Input

    ERIC Educational Resources Information Center

    Goldberg, Mayer

    2012-01-01

    In computing real-valued functions, it is ordinarily assumed that the input to the function is known, and it is the output that we need to approximate. In this work, we take the opposite approach: we show how to compute the values of some transcendental functions by approximating the input to these functions, and obtaining exact answers for their…

  3. Gravity Transform for Input Conditioning in

    E-print Network

    Paiva, António R. C.

    position Multiple input linear filter, followed by hard threshold Memory embedding: 10-tap delay line, filter weights measure modeling relevance of neurons and taps. Input variance i 2 must also be accounted for. In this work, the average "sensitivity" (over the taps) of the desired response to the i

  4. The Hipparcos Input Catalogue. Volumes 1 - 7

    Microsoft Academic Search

    C. Turon; M. Crézé; D. Egret; A. Gómez; M. Grenon; H. Jahreiß; Y. Réquième; A. N. Argue; A. Bec-Borsenberger; J. Dommanget; M. O. Mennessier; F. Arenou; M. Chareton; F. Crifo; J. C. Mermilliod; D. Morin; B. Nicolet; O. Nys; L. Prévot; M. Rousseau; M. A. C. Perryman; J. E. Arlot; A. Baglin; D. Barthès; M. O. Baylac; P. Brosche; M. Burnet; J. Delhaye; C. Dettbarn; M. Erbach; F. Figueras; W. Fricke; L. Helmer; P. Hemenway; C. Jordi; P. Lampens; T. Lederle; J. Lub; J. Manfroid; J. A. Mattei; J. M. Mazurier; M. Mermilliod; L. V. Morisson; C. A. Murray; E. Oblak; J. P. Périé; B. Pernier; R. S. Le Poole; L. Quijano; M. Rapaport; A. Sellier; J. Torra; H.-J. Tucholke; C. de Vegt; E. Høg; J. Kovalevsky; F. van Leeuwen; L. Lindegren; A. Schütz; H. Schrijver

    1992-01-01

    Vol. 1 - 5: The Hipparcos Input Catalogue. Vol. 6: Annex 1. Double and multiple stars. Vol. 7: Annex 2. The atlas of identification charts for faint stars. Annex 3. Identification charts for stars in galactic open clusters. Annex 4. Identification charts for stars in the Magellanic Clouds. The Hipparcos Input Catalogue was constructed as the observing programme for the

  5. Decorrelation of cortical inputs and motoneuron output.

    PubMed

    Negro, Francesco; Farina, Dario

    2011-11-01

    Oscillations in the primary motor cortex are transmitted through the corticospinal tract to the motoneuron pool. This pathway is believed to produce an effective and direct command from the motor cortex to the spinal motoneurons for the modulation of the force output. In this study, we used a computational model of a population of motoneurons to investigate the factors that can influence the transmission of the cortical input to the output of motoneurons, since it can be quantified by coherence analysis. The simulations demonstrated that, despite the nonlinearity of the motoneurons, oscillations present in the cortical input are transmitted to the output of the motoneuron pool at the same frequency. However, the interference introduced by the nonlinearity of the system increases the variability of the oscillations in output, introducing spectral lines whose frequency depends on the input frequencies and the motoneuron discharge rates. Moreover, an additional source of synaptic input common to all motoneurons but independent from the corticospinal component decorrelates the cortical input and motoneuron output and, thus, decreases the magnitude of the estimated coherence, even if the effective cortical drive does not change. These results indicate that the corticospinal input can effectively be sampled by a small population of motoneurons. However, the transmission of a corticospinal drive to the motoneuron pool is influenced by the nonlinearity of the spiking processes of the active motoneurons and by synaptic inputs common to the motoneuron population but independent from the cortical input. PMID:21795617

  6. Input-Output Analysis in Public Education.

    ERIC Educational Resources Information Center

    Cohn, Elchanan; And Others

    This study explores some techniques that could assist education managers in their attempt to arrive at more optimal input and output mixes. The first part (Chapters 1-4) provides an overview of the input-output concept in relation to its employment in the educational setting, along with a review of the literature on the educational production…

  7. Transliteration Based Text Input Methods for Telugu

    Microsoft Academic Search

    V. B. Sowmya; Vasudeva Varma

    2009-01-01

    Telugu is the third most spoken language in India and one of the fif- teen most spoken languages in the world. But, there is no standardized input method for Telugu, which has a widespread use. Since majority of users of Te- lugu typing tools on the computers are familiar with English, we propose a transliteration based text input method in

  8. Pseudo-telepathy: input cardinality and Bell-type inequalities

    E-print Network

    Gisin, Nicolas; Scarani, V

    2006-01-01

    Pseudo-telepathy is the most recent form of rejection of locality. Many of its properties have already been discovered: for instance, the minimal entanglement, as well as the minimal cardinality of the output sets, have been characterized. This paper contains two main results. First, we prove that no bipartite pseudo-telepathy game exists, in which one of the partners receives only two questions; as a corollary, we show that the minimal "input cardinality", that is, the minimal number of questions required in a bipartite pseudo-telepathy game, is 3x3. Second, we study the Bell-type inequality derived from the pseudo-telepathy game known as the Magic Square game: we demonstrate that it is a tight inequality for 3 inputs and 4 outputs on each side and discuss its weak resistance to noise.

  9. Pseudo-telepathy: input cardinality and Bell-type inequalities

    E-print Network

    N. Gisin; A. A. Methot; V. Scarani

    2006-10-20

    Pseudo-telepathy is the most recent form of rejection of locality. Many of its properties have already been discovered: for instance, the minimal entanglement, as well as the minimal cardinality of the output sets, have been characterized. This paper contains two main results. First, we prove that no bipartite pseudo-telepathy game exists, in which one of the partners receives only two questions; as a corollary, we show that the minimal "input cardinality", that is, the minimal number of questions required in a bipartite pseudo-telepathy game, is 3x3. Second, we study the Bell-type inequality derived from the pseudo-telepathy game known as the Magic Square game: we demonstrate that it is a tight inequality for 3 inputs and 4 outputs on each side and discuss its weak resistance to noise.

  10. Statistical identification of effective input variables. [SCREEN

    SciTech Connect

    Vaurio, J.K.

    1982-09-01

    A statistical sensitivity analysis procedure has been developed for ranking the input data of large computer codes in the order of sensitivity-importance. The method is economical for large codes with many input variables, since it uses a relatively small number of computer runs. No prior judgemental elimination of input variables is needed. The sceening method is based on stagewise correlation and extensive regression analysis of output values calculated with selected input value combinations. The regression process deals with multivariate nonlinear functions, and statistical tests are also available for identifying input variables that contribute to threshold effects, i.e., discontinuities in the output variables. A computer code SCREEN has been developed for implementing the screening techniques. The efficiency has been demonstrated by several examples and applied to a fast reactor safety analysis code (Venus-II). However, the methods and the coding are general and not limited to such applications.

  11. Microchannel cross load array with dense parallel input

    DOEpatents

    Swierkowski, Stefan P.

    2004-04-06

    An architecture or layout for microchannel arrays using T or Cross (+) loading for electrophoresis or other injection and separation chemistry that are performed in microfluidic configurations. This architecture enables a very dense layout of arrays of functionally identical shaped channels and it also solves the problem of simultaneously enabling efficient parallel shapes and biasing of the input wells, waste wells, and bias wells at the input end of the separation columns. One T load architecture uses circular holes with common rows, but not columns, which allows the flow paths for each channel to be identical in shape, using multiple mirror image pieces. Another T load architecture enables the access hole array to be formed on a biaxial, collinear grid suitable for EDM micromachining (square holes), with common rows and columns.

  12. An image-processing approach to dotplots: an X-Window-based program for interactive analysis of dotplots derived from sequence and structural data.

    PubMed

    Trelles-Salazar, O; Zapata, E L; Dopazo, J; Coulson, A F; Carazo, J M

    1995-06-01

    We present an approach to the study of the relationships between biological sequences and structures applying image analysis methods to dotplots. We introduce a set of analytical tools based on different types of digital image-processing filters that are new within the context of dotplots. We have reformulated some of the usual approaches in dotplot analysis as mathematical operations on images within the framework of mathematical morphology. An X-Window-based implementation of this new approach has been developed and is available by anonymous FTP. PMID:7583699

  13. Synthesis and biological evaluation of a novel (99m)Tc labeled 2-nitroimidazole derivative as a potential agent for imaging tumor hypoxia.

    PubMed

    Joyard, Yoann; Le Joncour, Vadim; Castel, Hélène; Diouf, Chérif Bounana; Bischoff, Laurent; Papamicaël, Cyril; Levacher, Vincent; Vera, Pierre; Bohn, Pierre

    2013-07-01

    Tumor hypoxia plays a major role in reducing the efficacy of therapeutic modalities like chemotherapy and radiation therapy in combating cancer. In order to target hypoxic tissues, a tripeptide ligand having a 2-nitroimidazole moiety, as a bioreductive species, was synthesized. The latter was radiolabeled with (99m)Tc for imaging hypoxic regions of tumors and was characterized by means of its rhenium analogue. The biodistribution and scintigraphic image of the corresponding (99m)Tc-complex showed accumulation in tumor and these results suggest that it could be a marker for imaging tumor hypoxia. PMID:23726027

  14. Initial evaluation of virtual un-enhanced imaging derived from fast kVp-switching dual energy contrast enhanced CT for the abdomen

    NASA Astrophysics Data System (ADS)

    Joshi, M.; Mendonca, P.; Okerlund, D.; Lamb, P.; Kulkarni, N.; Pinho, D.; Sahani, D.; Bhotika, R.

    2011-03-01

    The feasibility and utility of creating virtual un-enhanced images from contrast enhanced data acquired using a fast switching dual energy CT acquisition, is explored. Utilizing projection based material decomposition data, monochromatic images are generated and a Multi-material decomposition technique is applied. Quantitative and qualitative evaluation is performed to assess the equivalence of Virtual Un-Enhanced (VUE) and True Un-enhanced (TUE) for multiple tissue types and different organs in the abdomen. Ten patient cases were analyzed where a TUE and a subsequent Contrast Enhanced (CE) acquisition were obtained using fast kVp-switching dual energy CT utilizing Gemstone Spectral Imaging. Quantitative measurements were made by placing multiple Regions of Interest on the different tissues and organs in both the TUE and the VUE images. The absolute Hounsfield Unit (HU) differences in the mean values between TUE & VUE were calculated as well as the differences of the standard deviations. Qualitative analysis was done by two radiologists for overall image quality, presence of residual contrast, appearance of pathology, appearance and contrast of normal tissues and organs in comparison to the TUE. There is a very strong correlation between the TUE and VUE images.

  15. Quantum filtering for multiple input multiple output systems driven by arbitrary zero-mean jointly Gaussian input fields

    NASA Astrophysics Data System (ADS)

    Nurdin, H. I.

    2014-07-01

    In this paper, we treat the quantum filtering problem for multiple input multiple output (MIMO) Markovian open quantum systems coupled to multiple boson fields in an arbitrary zero-mean jointly Gaussian state, using the reference probability approach formulated by Bouten and van Handel as a quantum version of a well-known method of the same name from classical nonlinear filtering theory, and exploiting the generalized Araki-Woods representation of Gough. This includes Gaussian field states such as vacuum, squeezed vacuum, thermal, and squeezed thermal states as special cases. The contribution is a derivation of the general quantum filtering equation (or stochastic master equation as they are known in the quantum optics community) in the full MIMO setup for any zero-mean jointly Gaussian input field states, up to some mild rank assumptions on certain matrices relating to the measurement vector.

  16. A-Coord Input: Coordinating Auxiliary Input Streams for Augmenting Contextual Pen-Based Interactions

    E-print Network

    1 A-Coord Input: Coordinating Auxiliary Input Streams for Augmenting Contextual Pen a pen to write or draw. For this reason, digital pens are now embedded with auxiliary input sensors channels in conjunction which can facilitate a number of common tasks can on the pen. Author Keywords Pen

  17. Convergence of sensory inputs upon projection neurons of somatosensory cortex: Vestibular, neck, head, and forelimb inputs

    Microsoft Academic Search

    P. Zarzecki; P. S. Blum; D. A. Bakker; D. Herman

    1983-01-01

    Cortico-cortical neurons and pyramidal tract (PT) neurons of the cat cerebral cortex were tested for convergent inputs from electrically stimulated vestibular, neck, head and forelimb nerves. Neurons were recorded within forelimb and vestibular projection regions of cortical area 3a. Consideration was given to both suprathreshold and subthreshold inputs. Neither vestibular, neck nor head inputs were detected in the forelimb region

  18. Image enhancement by non-linear extrapolation in frequency space

    NASA Technical Reports Server (NTRS)

    Anderson, Charles H. (Inventor); Greenspan, Hayit K. (Inventor)

    1998-01-01

    An input image is enhanced to include spatial frequency components having frequencies higher than those in an input image. To this end, an edge map is generated from the input image using a high band pass filtering technique. An enhancing map is subsequently generated from the edge map, with the enhanced map having spatial frequencies exceeding an initial maximum spatial frequency of the input image. The enhanced map is generated by applying a non-linear operator to the edge map in a manner which preserves the phase transitions of the edges of the input image. The enhanced map is added to the input image to achieve a resulting image having spatial frequencies greater than those in the input image. Simplicity of computations and ease of implementation allow for image sharpening after enlargement and for real-time applications such as videophones, advanced definition television, zooming, and restoration of old motion pictures.

  19. A new synthesis for terrestrial nitrogen inputs

    NASA Astrophysics Data System (ADS)

    Houlton, B. Z.; Morford, S. L.

    2014-09-01

    Nitrogen (N) inputs sustain many different aspects of local soil processes, their services, and their interactions with the broader Earth system. We present a new synthesis for terrestrial N inputs that considers both rock and atmospheric sources. We review evidence for state-factor regulation over biological N fixation, deposition and rock weathering inputs from local to global scales and in transient vs. steady-state landscapes. Our framework highlights strong organism and topographic (relief) controls over all three N input pathways, with the anthropogenic factor clearly important in rising N deposition rates. In addition, the climate, parent material and time factors are shown to influence patterns of fixation and rock-weathering inputs of N in diverse soil-systems. Data reanalysis suggests that weathering of N-rich parent material could resolve several known cases of "missing N inputs" in ecosystems, and demonstrates how the inclusion of rock N sources into modern concepts can lead to a richer understanding of spatial and temporal patterns of ecosystem N availability. For example, explicit consideration of rock N inputs into classic pedogenic models (e.g., Walker and Syers model) yields a fundamentally different expectation from the standard case: weathering of N-rich parent material could enhance N availability and facilitate terrestrial succession in developmentally young sites even in the absence of N-fixing organisms. We conclude that a state-factor framework for N complements our growing understanding multiple-source controls on phosphorus and cation availability in Earth's soil; but with significant exceptions given the lack of an N fixation analogue in all other biogeochemical cycles. Rather, a state-factor analysis of N must recognize non-symmetrical feedbacks among input pathways, whereby high N inputs via deposition or rock weathering have the potential to reduce biological fixation rates within a given state-factor.

  20. Deriving adaptive MRF coefficients from previous normal-dose CT scan for low-dose image reconstruction via penalized weighted least-squares minimization

    PubMed Central

    Zhang, Hao; Han, Hao; Wang, Jing; Ma, Jianhua; Liu, Yan; Moore, William; Liang, Zhengrong

    2014-01-01

    Purpose: Repeated computed tomography (CT) scans are required for some clinical applications such as image-guided interventions. To optimize radiation dose utility, a normal-dose scan is often first performed to set up reference, followed by a series of low-dose scans for intervention. One common strategy to achieve the low-dose scan is to lower the x-ray tube current and exposure time (mAs) or tube voltage (kVp) setting in the scanning protocol, but the resulted image quality by the conventional filtered back-projection (FBP) method may be severely degraded due to the excessive noise. Penalized weighted least-squares (PWLS) image reconstruction has shown the potential to significantly improve the image quality from low-mAs acquisitions, where the penalty plays an important role. In this work, the authors' explore an adaptive Markov random field (MRF)-based penalty term by utilizing previous normal-dose scan to improve the subsequent low-dose scans image reconstruction. Methods: In this work, the authors employ the widely-used quadratic-form MRF as the penalty model and explore a novel idea of using the previous normal-dose scan to obtain the MRF coefficients for adaptive reconstruction of the low-dose images. In the coefficients determination, the authors further explore another novel idea of using the normal-dose scan to obtain a scale map, which describes an optimal neighborhood for the coefficients determination such that a local uniform region has a small spread of frequency spectrum and, therefore, a small MRF window, and vice versa. The proposed penalty term is incorporated into the PWLS image reconstruction framework, and the low-dose images are reconstructed via the PWLS minimization. Results: The presented adaptive MRF based PWLS algorithm was validated by physical phantom and patient data. The experimental results demonstrated that the presented algorithm is superior to the PWLS reconstruction using the conventional Gaussian MRF penalty or the edge-preserving Huber penalty and the conventional FBP method, in terms of image noise reduction and edge/detail/contrast preservation. Conclusions: This study demonstrated the feasibility and efficacy of the proposed scheme in utilizing previous normal-dose CT scan to improve the subsequent low-dose scans. PMID:24694147

  1. A comparison of rat SPECT images obtained using 99mTc derived from 99Mo produced by an electron accelerator with that from a reactor

    NASA Astrophysics Data System (ADS)

    Galea, R.; Wells, R. G.; Ross, C. K.; Lockwood, J.; Moore, K.; Harvey, J. T.; Isensee, G. H.

    2013-05-01

    Recent shortages of molybdenum-99 (99Mo) have led to an examination of alternate production methods that could contribute to a more robust supply. An electron accelerator and the photoneutron reaction were used to produce 99Mo from which technetium-99m (99mTc) is extracted. SPECT images of rat anatomy obtained using the accelerator-produced 99mTc with those obtained using 99mTc from a commercial generator were compared. Disks of 100Mo were irradiated with x-rays produced by a 35 MeV electron beam to generate about 1110 MBq (30 mCi) of 99Mo per disk. After target dissolution, a NorthStar ARSII unit was used to separate the 99mTc, which was subsequently used to tag pharmaceuticals suitable for cardiac and bone imaging. SPECT images were acquired for three rats and compared to images for the same three rats obtained using 99mTc from a standard reactor 99Mo generator. The efficiency of 99Mo-99mTc separation was typically greater than 90%. This study demonstrated the delivery of 99mTc from the end of beam to the end user of approximately 30 h. Images obtained using the heart and bone scanning agents using reactor and linac-produced 99mTc were comparable. High-power electron accelerators are an attractive option for producing 99Mo on a national scale.

  2. An Image Completion Algorithm Using Occlusion-Free Images from Internet Photo Sharing Sites

    NASA Astrophysics Data System (ADS)

    Amirshahi, Hanieh; Kondo, Satoshi; Ito, Koichi; Aoki, Takafumi

    In this paper, we propose an image completion algorithm which takes advantage of the countless number of images available on Internet photo sharing sites to replace occlusions in an input image. The algorithm 1) automatically selects the most suitable images from a database of downloaded images and 2) seamlessly completes the input image using the selected images with minimal user intervention. Experimental results on input images captured at various locations and scene conditions demonstrate the effectiveness of the proposed technique in seamlessly reconstructing user-defined occlusions.

  3. Staring 2-D hadamard transform spectral imager

    DOEpatents

    Gentry, Stephen M. (Albuquerque, NM); Wehlburg, Christine M. (Albuquerque, NM); Wehlburg, Joseph C. (Albuquerque, NM); Smith, Mark W. (Albuquerque, NM); Smith, Jody L. (Albuquerque, NM)

    2006-02-07

    A staring imaging system inputs a 2D spatial image containing multi-frequency spectral information. This image is encoded in one dimension of the image with a cyclic Hadamarid S-matrix. The resulting image is detecting with a spatial 2D detector; and a computer applies a Hadamard transform to recover the encoded image.

  4. Quantization noise in single-loop sigma-delta modulation with sinusoidal inputs

    Microsoft Academic Search

    ROBERT M. GRAY; W. Chou; P. W. Wong

    1989-01-01

    An exact nonlinear difference equation is derived and solved for a simple sigma-delta modulator consisting of a discrete-time integrator and a binary quantizer inside a single feedback loop and an arbitrary input signal. It is shown that the system can be represented as an affine operation (discrete-time integration of a biased input) followed by a memoryless nonlinearity. An extension of

  5. Lateralized inhibitory input to an identified nonspiking local interneuron in the crayfish mechanosensory system

    Microsoft Academic Search

    Wulf Dieter Krenz; Heinrich Reichert

    1985-01-01

    1.The LDS interneuron is an identified, nonspiking, local interneuron which mediates across-the-midline lateral inhibition of anteriorally projecting mechanosensory interneurons in the crayfish terminal ganglion (Fig. 1). We used single electrode current clamp techniques to investigate the nature of the synaptic input to the LDS inter-neuron.2.Afferent derived sensory input to an LDS interneuron consists of EPSPs and IPSPs both of which

  6. Input Estimation Method Including Finite-Element Scheme for Solving Inverse Heat Conduction Problems

    Microsoft Academic Search

    Tsung-Chien Chen; Pan-Chio Tuan

    2005-01-01

    This work presents an inverse method based on the input estimation method including the finite-element scheme to estimate unknown heat flux. The input estimation method is comprised of the Kalman filtering technique and a recursive least-squares estimator. This recursive least-squares estimator is weighted by the forgetting factor ?. It is derived using the residual innovation sequence to compute the magnitude

  7. Stability analysis of converter-grid interaction using the converter input admittance

    Microsoft Academic Search

    Lennart Harnefors; Massimo Bongiorno; Stefan Lundberg

    2007-01-01

    A grid-connected power electronic converter can cause local instabilities when interacting other subsystems-particularly poorly damped resonances-that are electrically nearby. However, oscillations at a certain frequency cannot build up due to the converter if its differential input admittance has positive conductance (real part) at that frequency, since power is then dissipated. Input-admittance expressions for a voltage-source converter are derived in this

  8. Synthesis of a potent and selective 18F-labeled ?-opioid receptor antagonist derived from the Dmt-Tic pharmacophore for PET imaging

    PubMed Central

    Ryu, Eun Kyoung; Wu, Zhanhong; Chen, Kai; Lazarus, Lawrence H.; Marczak, Ewa, D.; Sasaki, Yusuke; Ambo, Akihiro; Salvadori, Severo; Ren, Chuancheng; Zhao, Heng; Balboni, Gianfranco; Chen, Xiaoyuan

    2009-01-01

    H-Dmt-Tic-?-Lys(Z)-OH (1) was used in the synthesis of 18F-labeled opioids for positron emission tomography (PET) imaging by coupling N-succinimidyl-4-[18F]fluorobenzoate ([18F]SFB) with Boc-Dmt-Tic-?-Lys(Z)-OH under slightly basic conditions at 37 °C for 15 min, deprotected with TFA and HPLC purification in 120 min with a decay-corrected radiochemical 25–30% yield of [18F]-1 (n = 5) and specific activity ca. 46 GBq/µmol. Autoradiography uptake of [18F]-1 in striatum and cortex was blocked by 1 and UFP-501 demonstrating specific binding to ?-opioid receptors. MicroPET imaging revealed the absence of [18F]-1 in rat brain, suggesting its suitability for imaging peripheral ?-opioid receptors. PMID:18311909

  9. Two Input Polyhedra User Correspondence Specification

    E-print Network

    Whitton, Mary C.

    Two Input Polyhedra User Correspondence Specification through Decomposition into Mapping Merging Reconstruction Merged Polyhedron Isomorphic Polyhedra Editing of Morphing Trajectories Interpolation of Morphing-specified morphing between arbitrary polyhedra Department of Computer Science University of North Carolina at Chapel

  10. 7 CFR 3430.15 - Stakeholder input.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...input. Section 103(c)(2) of the Agricultural Research, Extension, and Education Reform Act of 1998...program RFA from persons who conduct agricultural research, education, and extension for use in formulating future RFAs...

  11. Some applications of three-dimensional input

    E-print Network

    Schmandt, Christopher

    1980-01-01

    Three-dimensional, six degree of freedom input is explored in an interactive computer graphics environment. A particular device, the ROPAMS of Polhemus Navigational Sciences, Inc. is an accurate, unencumbering device based ...

  12. Optimal input signals for bandlimited scanning systems

    E-print Network

    Fleming, Andrew J.

    dynamics. We focus on designing inputs for scanning probe microscope nano-positioning stages, as reviewed nanopositioning stage. Experimental results are followed by conclusions in Section 5. 2. SIGNAL OPTIMIZATION

  13. Derivation of formulas for root-mean-square errors in location, orientation, and shape in triangulation solution of an elongated object in space

    NASA Technical Reports Server (NTRS)

    Long, S. A. T.

    1974-01-01

    Formulas are derived for the root-mean-square (rms) displacement, slope, and curvature errors in an azimuth-elevation image trace of an elongated object in space, as functions of the number and spacing of the input data points and the rms elevation error in the individual input data points from a single observation station. Also, formulas are derived for the total rms displacement, slope, and curvature error vectors in the triangulation solution of an elongated object in space due to the rms displacement, slope, and curvature errors, respectively, in the azimuth-elevation image traces from different observation stations. The total rms displacement, slope, and curvature error vectors provide useful measure numbers for determining the relative merits of two or more different triangulation procedures applicable to elongated objects in space.

  14. Unlimited-size mosaicking of airborne image data

    NASA Astrophysics Data System (ADS)

    Jiang, Nan; Li, Changchun; Abousleman, Glen; Si, Jennie

    2007-04-01

    This paper presents a system that creates and navigates an unlimited-size mosaic with geographical information. The input is a sequence of airborne images with or without telemetry data, and the output is a mosaic with a combined geographical coordinate layer inherited from the input images. Rather than registering input images with an orthoimage, which is popular in existing applications, the proposed system only takes use of telemetry data as prior information. The airborne images embedded with geo-information are pair-wise registered, based on image feature correspondence. We extract feature points and form a modified EDGE-based descriptor for image registration. Subsequently, the geographical coordinate layers derived from the telemetry data stream are fused using a registration matrix computed from the previous step. However, due to the unreliability of the telemetry data, the new geodetic coordinate layer might be inconsistent with the image coordinate layer and therefore requires rectification to minimize the squared error between the mosaic coordinate layer and the warped geographical coordinate layer. The above process is incorporated into a cluster framework so that the output mosaic is extensible to an infinite size. That is, once the current mosaic size has expanded beyond computer memory limitations, the image is saved to a database. Its spatial relationship with respect to the world coordinate system is also saved to the database so that the system can navigate the collection of image mosaic data by querying the spatial database and retrieving the relevant mosaics. This method is especially suitable for video sequences spanning large regions, such as surveillance video from a micro UAV. Results with real-world UAV video are provided to demonstrate the performance of the proposed system.

  15. Significance of input correlations in striatal function.

    PubMed

    Yim, Man Yi; Aertsen, Ad; Kumar, Arvind

    2011-11-01

    The striatum is the main input station of the basal ganglia and is strongly associated with motor and cognitive functions. Anatomical evidence suggests that individual striatal neurons are unlikely to share their inputs from the cortex. Using a biologically realistic large-scale network model of striatum and cortico-striatal projections, we provide a functional interpretation of the special anatomical structure of these projections. Specifically, we show that weak pairwise correlation within the pool of inputs to individual striatal neurons enhances the saliency of signal representation in the striatum. By contrast, correlations among the input pools of different striatal neurons render the signal representation less distinct from background activity. We suggest that for the network architecture of the striatum, there is a preferred cortico-striatal input configuration for optimal signal representation. It is further enhanced by the low-rate asynchronous background activity in striatum, supported by the balance between feedforward and feedback inhibitions in the striatal network. Thus, an appropriate combination of rates and correlations in the striatal input sets the stage for action selection presumably implemented in the basal ganglia. PMID:22125480

  16. Hippocampal phase precession from dual input components.

    PubMed

    Chance, Frances S

    2012-11-21

    Phase precession is a well known phenomenon in which a hippocampal place cell will fire action potentials at successively earlier phases (relative to the theta-band oscillations recorded in the local field potential) as an animal moves through the cell's receptive field (also known as a place field). We present a model in which CA1 pyramidal cell spiking is driven by dual input components arising from CA3 and EC3. The receptive fields of these two input components overlap but are offset in space from each other such that as the animal moves through the model place field, action potentials are driven first by the CA3 input component and then the EC3 input component. As CA3 synaptic input is known to arrive in CA1 at a later theta phase than EC3 input (Mizuseki et al., 2009; Montgomery et al., 2009), CA1 spiking advances in phase as the model transitions from CA3-driven spiking to EC3-driven spiking. Here spike phase is a function of animal location, placing our results in agreement with many experimental observations characterizing CA1 phase precession (O'Keefe and Recce, 1993; Huxter et al., 2003; Geisler et al., 2007). We predict that experimental manipulations that dramatically enhance or disrupt activity in either of these areas should have a significant effect on phase precession observed in CA1. PMID:23175823

  17. Input filter compensation for switching regulators

    NASA Technical Reports Server (NTRS)

    Kelkar, S. S.; Lee, F. C.

    1983-01-01

    A novel input filter compensation scheme for a buck regulator that eliminates the interaction between the input filter output impedance and the regulator control loop is presented. The scheme is implemented using a feedforward loop that senses the input filter state variables and uses this information to modulate the duty cycle signal. The feedforward design process presented is seen to be straightforward and the feedforward easy to implement. Extensive experimental data supported by analytical results show that significant performance improvement is achieved with the use of feedforward in the following performance categories: loop stability, audiosusceptibility, output impedance and transient response. The use of feedforward results in isolating the switching regulator from its power source thus eliminating all interaction between the regulator and equipment upstream. In addition the use of feedforward removes some of the input filter design constraints and makes the input filter design process simpler thus making it possible to optimize the input filter. The concept of feedforward compensation can also be extended to other types of switching regulators.

  18. Rapid Airplane Parametric Input Design (RAPID)

    NASA Technical Reports Server (NTRS)

    Smith, Robert E.

    1995-01-01

    RAPID is a methodology and software system to define a class of airplane configurations and directly evaluate surface grids, volume grids, and grid sensitivity on and about the configurations. A distinguishing characteristic which separates RAPID from other airplane surface modellers is that the output grids and grid sensitivity are directly applicable in CFD analysis. A small set of design parameters and grid control parameters govern the process which is incorporated into interactive software for 'real time' visual analysis and into batch software for the application of optimization technology. The computed surface grids and volume grids are suitable for a wide range of Computational Fluid Dynamics (CFD) simulation. The general airplane configuration has wing, fuselage, horizontal tail, and vertical tail components. The double-delta wing and tail components are manifested by solving a fourth order partial differential equation (PDE) subject to Dirichlet and Neumann boundary conditions. The design parameters are incorporated into the boundary conditions and therefore govern the shapes of the surfaces. The PDE solution yields a smooth transition between boundaries. Surface grids suitable for CFD calculation are created by establishing an H-type topology about the configuration and incorporating grid spacing functions in the PDE equation for the lifting components and the fuselage definition equations. User specified grid parameters govern the location and degree of grid concentration. A two-block volume grid about a configuration is calculated using the Control Point Form (CPF) technique. The interactive software, which runs on Silicon Graphics IRIS workstations, allows design parameters to be continuously varied and the resulting surface grid to be observed in real time. The batch software computes both the surface and volume grids and also computes the sensitivity of the output grid with respect to the input design parameters by applying the precompiler tool ADIFOR to the grid generation program. The output of ADIFOR is a new source code containing the old code plus expressions for derivatives of specified dependent variables (grid coordinates) with respect to specified independent variables (design parameters). The RAPID methodology and software provide a means of rapidly defining numerical prototypes, grids, and grid sensitivity of a class of airplane configurations. This technology and software is highly useful for CFD research for preliminary design and optimization processes.

  19. Assessing and predicting biodiversity in a floodplain ecosystem: Assimilation of net primary production derived from imaging spectrometer data into a dynamic vegetation model

    Microsoft Academic Search

    Lammert Kooistra; Wieger Wamelink; Gabriela Schaepman-Strub; Michael Schaepman; Han van Dobben; Uchenna Aduaka; Okke Batelaan

    2008-01-01

    New concepts for river management in northwestern Europe are being developed which aim at both flood protection and nature conservation. As a result, methods are required that assess the effect of management activities on the biodiversity of floodplain ecosystems. In this paper, we show that dynamic vegetation models (DVMs) in combination with regional scale derived remote sensing products can be

  20. Input functions for 6-[fluorine-18]Fluorodopa quantitation in parkinsonism: Comparative studies and clinical correlations

    SciTech Connect

    Takikawa, S.; Dhawan, V.; Chaly, T.; Robeson, W.; Dahl, R.; Zanzi, I.; Mandel, F.; Spetsieris, P.; Eidelberg, D. [North Shore Univ. Hospital/Cornell Univ., Medical College, Manhasset, NY (United States)

    1994-06-01

    PET has been used to quantify striatal 6-[{sup 18}F]fluro-L-dopa (FDOPA) uptake as a measure of presynaptic dopaminergic function. Striatal FDOPA uptake rate constants (K{sub 1}) can be calculated using dynamic PET imaging with measurements of the plasma FDOPA input function determined either directly or by several estimation procedures. The authors assessed the comparative clinical utility of these methods by calculating the striato-occipital ratio (SOR) and striatal K{sub 1} values in 12 patients with mild to moderate PD and 12 age-matched normal volunteers. The plasma FDOPA time-activity curve (K{sub 1}{sup FD}); the plasma {sup 18}F time-activity curve (K{sub i}{sup P}); the occipital time-activity curve (K{sub i}{sup OCC}); and a simplified population-derived FDOPA input function (K{sub i}{sup EFD}) were used to calculate striatal K{sub i}. Mean values for all striatal K{sub i} estimates and SOR were significantly lower in the PD group. Although all measured parameters discriminated PD patients with normals, K{sub i}{sup FD} and K{sub i}{sup EFD} provided the best between-group separation. K{sub i}{sup FD}, K{sub i}{sup EFD}, and K{sub i}{sup OCC} measures correlated significantly with quantitative disease severity ratings, although K{sub i}{sup FD} predicted quantitative clinical disability most accurately. These results suggest that K{sub i}{sup FD} may be an optimal marker of the parkinsonian disease process. K{sub i}{sup EFD} may be a useful alternative to K{sub i}{sup FD} for most clinical research applications. 40 refs., 4 figs., 7 tabs.

  1. The computational complexity of matching an input fingerprint against every entry in a large-scale fingerprint

    E-print Network

    Ross, Arun Abraham

    1 Abstract The computational complexity of matching an input fingerprint against every entry in a large-scale fingerprint database can be prohibitive. In fingerprint indexing, a small set of candidate fingerprints is selected from the database and only images in this set are compared against the input probe

  2. Velocital information feature for charting spatio-temporal changes in digital image sequences

    NASA Astrophysics Data System (ADS)

    Power, Gregory J.; Karim, Mohammad A.; Ahmed, Farid

    1999-04-01

    This paper introduces a velocital information feature that is extracted for each frame of an image sequence. The feature is based on the optical flow in each frame. A mathematical formulation for the velocital information feature is derived. Charting the feature over a sequence produces a quality metric called velocital information content (VIC). The relationship of VIC to the spatial and temporal information content is shown. VIC offers a different role from traditional transmission-based quality metrics which require two images: the original input image and degraded output image to calculate the quality metric. VIC can detect artifacts from a single image sequence by charting variations from the norm. Therefore, VIC offers a metric for judging the quality of the image frames prior to transmission, without a transmission system or without any knowledge of the higher quality image input. The differences between VIC and transmission-oriented quality metrics, can provide a different role for VIC in analysis and image sequence processing. Results show that VIC is able to detect gradual and sudden changes in an image sequence. Results are shown for using VIC as a filter on electro-optical infrared image sequences where VIC detects frames suffering from erratic noise.

  3. Input-output parametric models for non-linear systems Part I: deterministic non-linear systems

    Microsoft Academic Search

    I. J. LEONTARITIS; S. A. BILLINGS

    1985-01-01

    Recursive input-output models for non-linear multivariate discrete-time systems are derived, and sufficient conditions for their existence are defined. The paper is divided into two parts. The first part introduces and defines concepts such as Nerode realization, multistructural forms and results from differential geometry which are then used to derive a recursive input-output model for multivariable deterministic non-linear systems. The second

  4. Influences of urbanization on surface characteristics as derived from the Moderate-Resolution Imaging Spectroradiometer: A case study for the Beijing metropolitan area

    Microsoft Academic Search

    Kaicun Wang; Jiankai Wang; Pucai Wang; Michael Sparrow; Juan Yang; Hongbin Chen

    2007-01-01

    Moderate-Resolution Imaging Spectroradiometer (MODIS) global land surface temperature\\/emissivity (LST), vegetation indices, BRDF\\/Albedo and land cover products collected for the period of March 2000 to March 2006 are combined with the surface heat fluxes retrieved from MODIS as well as meteorological data to investigate the influence of urbanization associated with the surface characteristics of the city of Beijing. The results show

  5. Derivative chameleons

    SciTech Connect

    Noller, Johannes, E-mail: johannes.noller08@imperial.ac.uk [Theoretical Physics, Blackett Laboratory, Imperial College London, Prince Consort Road, London, SW7 2BZ (United Kingdom)

    2012-07-01

    We consider generalized chameleon models where the conformal coupling between matter and gravitational geometries is not only a function of the chameleon field ?, but also of its derivatives via higher order co-ordinate invariants (such as ?{sub ?}??{sup ?}?,??,...). Specifically we consider the first such non-trivial conformal factor A(?,?{sub ?}??{sup ?}?). The associated phenomenology is investigated and we show that such theories have a new generic mass-altering mechanism, potentially assisting the generation of a sufficiently large chameleon mass in dense environments. The most general effective potential is derived for such derivative chameleon setups and explicit examples are given. Interestingly this points us to the existence of a purely derivative chameleon protected by a shift symmetry for ? ? ?+c. We also discuss potential ghost-like instabilities associated with mass-lifting mechanisms and find another, mass-lowering and instability-free, branch of solutions. This suggests that, barring fine-tuning, stable derivative models are in fact typically anti-chameleons that suppress the field's mass in dense environments. Furthermore we investigate modifications to the thin-shell regime and prove a no-go theorem for chameleon effects in non-conformal geometries of the disformal type.

  6. Cumulative input function method for linear compartmental models and spectral analysis in PET

    PubMed Central

    Simoncic, Urban; Jeraj, Robert

    2011-01-01

    Compartmental modeling and spectral analysis are often used for tracer kinetic modeling in positron emission tomography (PET). The concentrations in kinetic equations are usually considered to be instantaneous, whereas PET data are inherently integrated over time, which leads to uncertainties in the results. A new formalism for kinetic analysis that uses cumulative tracer concentrations and avoids approximating the image-derived input function and PET measurements with midframe instantanous values was developed. We assessed the improvements of the new formalism over the midframe approximation methods for three commonly used radiopharmaceuticals: [11C]raclopride, 2?-deoxy-2?-[18F]fluoro--glucose (FDG), and 3?-deoxy-3?-[18F]fluoro-thymidine (FLT). We found that improvements are case dependent and often not negligible. Improvements for determination of binding potential for [11C]raclopride ranged from 5% to 25%. Improvements in estimation accuracy of FDG and FLT microparameters ranged up to 25%. On the other hand, estimation of macroparameter Ki=K1k3/(k2+k3) for FDG or FLT did not show significant benefit with the new method; only modest improvement up to 2% was observed. Assessment of the benefits of using new method is far from being exhaustive, but possibly significant improvement was demonstrated. Therefore, we consider the proposed algorithm a necessary component of any kinetic analysis software. PMID:20808319

  7. Input permutation method to detect active voxels in fMRI study?

    PubMed Central

    Lee, Sang H.; Lim, Johan; Park, DoHwan; Biswal, Bharat B.; Petkova, Eva

    2013-01-01

    Correctly identifying voxels or regions of interest (ROI) that actively respond to a given stimulus is often an important objective/step in many functional magnetic resonance imaging (fMRI) studies. In this article, we study a nonparametric method to detect active voxels, which makes minimal assumption about the distribution of blood oxygen level-dependent (BOLD) signals. Our proposal has several interesting features. It uses time lagged correlation to take into account the delay in response to the stimulus, due to hemodynamic variations. We introduce an input permutation method (IPM), a type of block permutation method, to approximate the null distribution of the test statistic. Also, we propose to pool the permutation-derived statistics of preselected voxels for a better approximation to the null distribution. Finally, we control multiple testing error rate using the local false discovery rate (FDR) by Efron [Correlation and large-scale simultaneous hypothesis testing. J Am Stat Assoc 102 (2007) 93–103] and Park et al. [Estimation of empirical null using a mixture of normals and its use in local false discovery rate. Comput Stat Data Anal 55 (2011) 2421–2432] to select the active voxels. PMID:22819177

  8. Scaling of increased dissolved organic carbon inputs by forest clear-cutting - What arrives downstream?

    NASA Astrophysics Data System (ADS)

    Schelker, Jakob; Öhman, Karin; Löfgren, Stefan; Laudon, Hjalmar

    2014-05-01

    Forest clear-cutting has been found to significantly increase concentrations of dissolved organic carbon (DOC) in boreal first-order streams. Here, we address the questions of 1) how the additional inputs of DOC by upstream forest harvesting affect downstream locations within a stream network and 2) what catchment area has to be harvested to cause a significant downstream increase in DOC concentration. We combined the use of primary data from a paired-catchment experiment, clear-cut history of a nested stream network derived from satellite images with a mixing-model approach in order to quantify the importance of upstream clear-cuts on two downstream sites with different catchment sizes. Modeled [DOC] agreed well with the measured concentrations in the smaller, 8.7 km2 catchment located above a larger wetland area, but discrepancies occurred for the larger 22.9 km2 catchment located downstream of the wetland. Estimates of the critical area (Acritical) needed to be harvested to cause a significant impact on downstream DOC concentrations was quantified to be 11% for p

  9. An update of input instructions to TEMOD

    NASA Technical Reports Server (NTRS)

    1973-01-01

    The theory and operation of a FORTRAN 4 computer code, designated as TEMOD, used to calcuate tubular thermoelectric generator performance is described in WANL-TME-1906. The original version of TEMOD was developed in 1969. A description is given of additions to the mathematical model and an update of the input instructions to the code. Although the basic mathematical model described in WANL-TME-1906 has remained unchanged, a substantial number of input/output options were added to allow completion of module performance parametrics as required in support of the compact thermoelectric converter system technology program.

  10. Using digital image processing to characterize the Campbell-Stokes sunshine recorder and to derive high-temporal resolution direct solar irradiance

    NASA Astrophysics Data System (ADS)

    Sanchez-Romero, A.; González, J. A.; Calbó, J.; Sanchez-Lorenzo, A.

    2014-09-01

    The Campbell-Stokes sunshine recorder (CSSR) has been one of the most commonly used instruments for measuring sunshine duration (SD) through the burn length of a given CSSR card. Many authors have used SD to obtain information about cloudiness and solar radiation (by using Ångström-Prescott type formulas). Contrarily, the burn width has not been used systematically. In principle, the burn width increases for increasing direct beam irradiance. The aim of this research is to show the relationship between burn width and direct solar irradiance (DSI), and to prove whether this relationship depends on the type of CSSR and burning card. A semi-automatic method based on image processing of digital scanned images of burnt cards is presented. With this method, the temporal evolution of the burn width with 1 min resolution can be obtained. From this, SD is easily calculated and compared with the traditional (i.e. visual) determination. The method tends to slightly overestimate SD but the thresholds that are used in the image processing could be adjusted to obtain an unbiased estimation. Regarding the burn width, results show that there is a high correlation between two different models of CSSRs, as well as a strong relationship between burn widths and DSI at a high-temporal resolution. Thus, for example, hourly DSI may be estimated from the burn width with higher accuracy than based on burn length (for one of the CSSR, relative root mean squared error 24 and 30% respectively; mean bias error -0.6 and -30.0 W m-2 respectively). The method offers a practical way to exploit long-term sets of CSSR cards to create long time series of DSI. Since DSI is affected by atmospheric aerosol content, CSSR records may also become a proxy measurement for turbidity and atmospheric aerosol loading.

  11. Using digital image processing to characterize the Campbell-Stokes sunshine recorder and to derive high-temporal resolution direct solar irradiance

    NASA Astrophysics Data System (ADS)

    Sanchez-Romero, A.; González, J. A.; Calbó, J.; Sanchez-Lorenzo, A.

    2015-01-01

    The Campbell-Stokes sunshine recorder (CSSR) has been one of the most commonly used instruments for measuring sunshine duration (SD) through the burn length of a given CSSR card. Many authors have used SD to obtain information about cloudiness and solar radiation (by using Ångström-Prescott type formulas), but the burn width has not been used systematically. In principle, the burn width increases for increasing direct beam irradiance. The aim of this research is to show the relationship between burn width and direct solar irradiance (DSI) and to prove whether this relationship depends on the type of CSSR and burning card. A method of analysis based on image processing of digital scanned images of burned cards is used. With this method, the temporal evolution of the burn width with 1 min resolution can be obtained. From this, SD is easily calculated and compared with the traditional (i.e., visual) determination. The method tends to slightly overestimate SD, but the thresholds that are used in the image processing could be adjusted to obtain an improved estimation. Regarding the burn width, experimental results show that there is a high correlation between two different models of CSSRs, as well as a strong relationship between burn widths and DSI at a high-temporal resolution. Thus, for example, hourly DSI may be estimated from the burn width with higher accuracy than based on burn length (for one of the CSSR, relative root mean squared error is 24 and 30%, respectively; mean bias error is -0.6 and -30.0 W m-2, respectively). The method offers a practical way to exploit long-term sets of CSSR cards to create long time series of DSI. Since DSI is affected by atmospheric aerosol content, CSSR records may also become a proxy measurement for turbidity and atmospheric aerosol loading.

  12. Three-input majority logic gate and multiple input logic circuit based on DNA strand displacement.

    PubMed

    Li, Wei; Yang, Yang; Yan, Hao; Liu, Yan

    2013-06-12

    In biomolecular programming, the properties of biomolecules such as proteins and nucleic acids are harnessed for computational purposes. The field has gained considerable attention due to the possibility of exploiting the massive parallelism that is inherent in natural systems to solve computational problems. DNA has already been used to build complex molecular circuits, where the basic building blocks are logic gates that produce single outputs from one or more logical inputs. We designed and experimentally realized a three-input majority gate based on DNA strand displacement. One of the key features of a three-input majority gate is that the three inputs have equal priority, and the output will be true if any of the two inputs are true. Our design consists of a central, circular DNA strand with three unique domains between which are identical joint sequences. Before inputs are introduced to the system, each domain and half of each joint is protected by one complementary ssDNA that displays a toehold for subsequent displacement by the corresponding input. With this design the relationship between any two domains is analogous to the relationship between inputs in a majority gate. Displacing two or more of the protection strands will expose at least one complete joint and return a true output; displacing none or only one of the protection strands will not expose a complete joint and will return a false output. Further, we designed and realized a complex five-input logic gate based on the majority gate described here. By controlling two of the five inputs the complex gate can realize every combination of OR and AND gates of the other three inputs. PMID:23710909

  13. Highly selective turn-on fluorescent sensor for nanomolar detection of biologically important Zn2+ based on isonicotinohydrazide derivative: application in cellular imaging.

    PubMed

    Tayade, Kundan; Sahoo, Suban K; Bondhopadhyay, Banashree; Bhardwaj, Vimal K; Singh, Narinder; Basu, Anupam; Bendre, Ratnamala; Kuwar, Anil

    2014-11-15

    A new Zn(2+) selective chemosensor (3) was synthesized by condensation of commercially available substituted salicylaldehyde and isonicotinohydrazide, and characterized by single crystal X-ray crystallography. Receptor 3 with Zn(2+) exhibited a highly selective and pronounced enhancement in the fluorescence emission among different cations by forming a 2:1 complex. The receptor can detect Zn(2+) up to nanomolar level (6.75 nM) with good tolerance of other metal ions and can be used for in vitro cellular imaging. PMID:24934743

  14. Contrast-guided image interpolation.

    PubMed

    Wei, Zhe; Ma, Kai-Kuang

    2013-11-01

    In this paper a contrast-guided image interpolation method is proposed that incorporates contrast information into the image interpolation process. Given the image under interpolation, four binary contrast-guided decision maps (CDMs) are generated and used to guide the interpolation filtering through two sequential stages: 1) the 45(°) and 135(°) CDMs for interpolating the diagonal pixels and 2) the 0(°) and 90(°) CDMs for interpolating the row and column pixels. After applying edge detection to the input image, the generation of a CDM lies in evaluating those nearby non-edge pixels of each detected edge for re-classifying them possibly as edge pixels. This decision is realized by solving two generalized diffusion equations over the computed directional variation (DV) fields using a derived numerical approach to diffuse or spread the contrast boundaries or edges, respectively. The amount of diffusion or spreading is proportional to the amount of local contrast measured at each detected edge. The diffused DV fields are then thresholded for yielding the binary CDMs, respectively. Therefore, the decision bands with variable widths will be created on each CDM. The two CDMs generated in each stage will be exploited as the guidance maps to conduct the interpolation process: for each declared edge pixel on the CDM, a 1-D directional filtering will be applied to estimate its associated to-be-interpolated pixel along the direction as indicated by the respective CDM; otherwise, a 2-D directionless or isotropic filtering will be used instead to estimate the associated missing pixels for each declared non-edge pixel. Extensive simulation results have clearly shown that the proposed contrast-guided image interpolation is superior to other state-of-the-art edge-guided image interpolation methods. In addition, the computational complexity is relatively low when compared with existing methods; hence, it is fairly attractive for real-time image applications. PMID:23846469

  15. Periocular and Intra-Articular Injection of Canine Adipose-Derived Mesenchymal Stem Cells: An In Vivo Imaging and Migration Study

    PubMed Central

    Wood, Joshua A.; Chung, Dai-Jung; Park, Shin Ae; Zwingenberger, Allison L.; Reilly, Christopher M.; Ly, Irene; Walker, Naomi J.; Vernau, William; Hayashi, Kei; Wisner, Erik R.; Cannon, Matthew S.; Kass, Philip H.; Cherry, Simon R.; Borjesson, Dori L.; Russell, Paul

    2012-01-01

    Abstract Purpose Immune-mediated diseases affect millions of people worldwide with an economic impact measured in the billions of dollars. Mesenchymal stem cells (MSCs) are being investigated in the treatment of certain immune mediated diseases, but their application in the treatment of the majority of these disorders remains largely unexplored. Keratoconjunctivitis sicca can occur as a result of progressive immune-mediated destruction of lacrimal tissue in dogs and humans, and immune-mediated joint disease is common to both species. In dogs, allogeneic MSC engraftment and migration have yet to be investigated in vivo in the context of repeated injections. Methods With these aims in mind, the engraftment of allogeneic canine MSCs after an injection into the periocular and intra-articular regions was followed in vivo using magnetic resonance and fluorescent imaging. Results The cells were shown to be resident near the site of the injection for a minimum of 2 weeks. Analysis of 61 tissues demonstrated preferential migration and subsequent engraftment of MSCs in the thymus as well as the gastrointestinal tract. These results also detail a novel in vivo imaging technique and demonstrate the differential spatial distribution of MSCs after migration away from the sites of local delivery. Conclusion The active engraftment of the MSCs in combination with their previously documented immunomodulatory capabilities suggests the potential for therapeutic benefit in using MSCs for the treatment of periocular and joint diseases with immune involvement. PMID:22175793

  16. Evaluation of entropy and JM-distance criterions as features selection methods using spectral and spatial features derived from LANDSAT images

    NASA Technical Reports Server (NTRS)

    Parada, N. D. J. (principal investigator); Dutra, L. V.; Mascarenhas, N. D. A.; Mitsuo, Fernando Augusta, II

    1984-01-01

    A study area near Ribeirao Preto in Sao Paulo state was selected, with predominance in sugar cane. Eight features were extracted from the 4 original bands of LANDSAT image, using low-pass and high-pass filtering to obtain spatial features. There were 5 training sites in order to acquire the necessary parameters. Two groups of four channels were selected from 12 channels using JM-distance and entropy criterions. The number of selected channels was defined by physical restrictions of the image analyzer and computacional costs. The evaluation was performed by extracting the confusion matrix for training and tests areas, with a maximum likelihood classifier, and by defining performance indexes based on those matrixes for each group of channels. Results show that in spatial features and supervised classification, the entropy criterion is better in the sense that allows a more accurate and generalized definition of class signature. On the other hand, JM-distance criterion strongly reduces the misclassification within training areas.

  17. Long run input use-input price relations and the cost function Hessian

    Microsoft Academic Search

    Ian Steedman

    By definition, to compare alternative long run equilibria is to compare alternative points on the real input price frontier. It follows at once that one can never move between long run equilibria by changing just one input price; one must change at least two. And in some cases, indeed, such as the Wicksellian one, to change one price is ipso

  18. Parametric images of myocardial metabolic rate of glucose generated from dynamic cardiac PET and 2-( sup 18 F)fluoro-2-deoxy-d-glucose studies

    SciTech Connect

    Choi, Y.; Hawkins, R.A.; Huang, S.C.; Gambhir, S.S.; Brunken, R.C.; Phelps, M.E.; Schelbert, H.R. (UCLA School of Medicine (USA))

    1991-04-01

    We describe a method for generating parametric images of the myocardial metabolic rate of glucose (MMRGlc) with positron emission tomography (PET). The method employs serially acquired images of 2-({sup 18}F)fluoro-2-deoxy-D-glucose (FDG) uptake and a Patlak graphical analysis of the image data. The arterial input function is derived from images of the left ventricular blood pool calibrated with {sup 18}F-plasma measurements. The approach is computationally fast enough to be used in a clinical environment. The MMRGlc parametric images improve myocardial contrast relative to non-parametric images, especially in studies with poor myocardial uptake of FDG. In addition, MMRGlc parametric images consolidate the large amount of data in a dynamic PET study into a clinically usable image set.

  19. BIL 415 -Image Processing Practicum Department of Computer Engineering

    E-print Network

    Erdem, Erkut

    BIL 415 - Image Processing Practicum Department of Computer Engineering Problem Set 2 Fall '2014-2015 Dr. Erkut Erdem TAs. Levent Karacan Create Your Own Image Effects Due Date: 23:59pm on Friday, October 31st, 2014 a) Input b)Created Effect Figure 1: Input image and created image effect by using

  20. Hydrogen Generation Rate Model Calculation Input Data

    SciTech Connect

    KUFAHL, M.A.

    2000-04-27

    This report documents the procedures and techniques utilized in the collection and analysis of analyte input data values in support of the flammable gas hazard safety analyses. This document represents the analyses of data current at the time of its writing and does not account for data available since then.

  1. Voice Input: Implications for Business Education.

    ERIC Educational Resources Information Center

    Andera, Frank

    1989-01-01

    In the future, business education curricula using electronic data processing will need to incorporate voice input into the various courses. Skill development in the creation of written communication by voice will require the emphasis of dictation skills, while the use of shorthand to record dictation will become obsolete. (JOW)

  2. Micromachined dual input axis rate gyroscope

    Microsoft Academic Search

    Thor Nelson Juneau

    1997-01-01

    The need for inexpensive yet reliable angular rate sensors in fields ranging from automotive to consumer electronics has motivated prolific micromachined rate gyroscope research. The vast majority of research has focused on single input axis rate gyroscopes based upon either translational resonance, such as tuning forks, or structural mode resonance, such as vibrating rings. However, this work presents a novel,

  3. MODEL PREDICTIVE CONTROL WITH GENERALIZED INPUT PARAMETRIZATION

    E-print Network

    Van den Hof, Paul

    MODEL PREDICTIVE CONTROL WITH GENERALIZED INPUT PARAMETRIZATION Edwin T. van Donkelaar, Okko H.t.vandonkelaar@wbmt.tudelft.nl Keywords : model predictive control, parametrization. Abstract In this article it is investigated how in model predictive control to improve the trade-o between performance and com- plexity. An e cient

  4. Gas compressor directly driven through heat input

    Microsoft Academic Search

    Eder

    1988-01-01

    A thermomechanical converter driven through heat input is described comprising: a primary circuit including: a working cylinder; an axial displacement reciprocating piston in the cylinder defining first and second zones on opposite sides of the piston, respectively containing a hot portion of a working gas and a cool portion of the working gas; a cooler connected to the outlet and

  5. Input and Intake in Language Acquisition

    ERIC Educational Resources Information Center

    Gagliardi, Ann C.

    2012-01-01

    This dissertation presents an approach for a productive way forward in the study of language acquisition, sealing the rift between claims of an innate linguistic hypothesis space and powerful domain general statistical inference. This approach breaks language acquisition into its component parts, distinguishing the input in the environment from…

  6. Consanguine Calculations Input File: blood.in

    E-print Network

    California at Berkeley, University of

    1 of 20 Problem A+ Consanguine Calculations Input File: blood.in Every person's blood has 2 markers in a particular ABO blood type for that person. Combination ABO Blood Type AA A AB AB AO A BB B BO B OO O Likewise, every person has two alleles for the blood Rh factor, represented by the characters + and -. Someone who

  7. DO MODEL UNCERTAINTY WITH CORRELATED INPUTS

    EPA Science Inventory

    The effect of correlation among the input parameters and variables on the output uncertainty of the Streeter-Phelps water quality model is examined. hree uncertainty analysis techniques are used: sensitivity analysis, first-order error analysis, and Monte Carlo simulation. odifie...

  8. Selecting training inputs via greedy rank covering

    SciTech Connect

    Buchsbaum, A.L.; Santen, J.P.H. van [AT& T Bell Laboratories, Murray Hill, NJ (United States)

    1996-12-31

    We present a general method for selecting a small set of training inputs, the observations of which will suffice to estimate the parameters of a given linear model. We exemplify the algorithm in terms of predicting segmental duration of phonetic-segment feature vectors in a text-to-speech synthesizer, but the algorithm will work for any linear model and its associated domain.

  9. Adaptive Random Testing with Combinatorial Input Domain

    PubMed Central

    Lu, Yansheng

    2014-01-01

    Random testing (RT) is a fundamental testing technique to assess software reliability, by simply selecting test cases in a random manner from the whole input domain. As an enhancement of RT, adaptive random testing (ART) has better failure-detection capability and has been widely applied in different scenarios, such as numerical programs, some object-oriented programs, and mobile applications. However, not much work has been done on the effectiveness of ART for the programs with combinatorial input domain (i.e., the set of categorical data). To extend the ideas to the testing for combinatorial input domain, we have adopted different similarity measures that are widely used for categorical data in data mining and have proposed two similarity measures based on interaction coverage. Then, we propose a new version named ART-CID as an extension of ART in combinatorial input domain, which selects an element from categorical data as the next test case such that it has the lowest similarity against already generated test cases. Experimental results show that ART-CID generally performs better than RT, with respect to different evaluation metrics. PMID:24772036

  10. Soil Organic Carbon Input from Urban Turfgrasses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Turfgrass is a major vegetation type in the urban and suburban environment. Management practices such as species selection, irrigation, and mowing may affect carbon (C) input and storage in these systems. Research was conducted to determine the rate of soil organic carbon (SOC) changes, soil carbon ...

  11. Image processing and recognition for biological images

    PubMed Central

    Uchida, Seiichi

    2013-01-01

    This paper reviews image processing and pattern recognition techniques, which will be useful to analyze bioimages. Although this paper does not provide their technical details, it will be possible to grasp their main tasks and typical tools to handle the tasks. Image processing is a large research area to improve the visibility of an input image and acquire some valuable information from it. As the main tasks of image processing, this paper introduces gray-level transformation, binarization, image filtering, image segmentation, visual object tracking, optical flow and image registration. Image pattern recognition is the technique to classify an input image into one of the predefined classes and also has a large research area. This paper overviews its two main modules, that is, feature extraction module and classification module. Throughout the paper, it will be emphasized that bioimage is a very difficult target for even state-of-the-art image processing and pattern recognition techniques due to noises, deformations, etc. This paper is expected to be one tutorial guide to bridge biology and image processing researchers for their further collaboration to tackle such a difficult target. PMID:23560739

  12. Successful Fluorescence-Guided Surgery on Human Colon Cancer Patient-Derived Orthotopic Xenograft Mouse Models Using a Fluorophore-Conjugated Anti-CEA Antibody and a Portable Imaging System

    PubMed Central

    Hiroshima, Yukihiko; Maawy, Ali; Metildi, Cristina A.; Zhang, Yong; Uehara, Fuminari; Miwa, Shinji; Yano, Shuya; Sato, Sho; Murakami, Takashi; Momiyama, Masashi; Chishima, Takashi; Tanaka, Kuniya; Endo, Itaru; Hoffman, Robert M.

    2014-01-01

    Abstract Background: Fluorescence-guided surgery (FGS) can enable successful cancer surgery where bright-light surgery often cannot. There are three important issues for FGS going forward toward the clinic: (a) proper tumor labeling, (b) a simple portable imaging system for the operating room, and (c) patient-like mouse models in which to develop the technology. The present report addresses all three. Materials and Methods: Patient colon tumors were initially established subcutaneously in nonobese diabetic (NOD)/severe combined immune deficiency (SCID) mice immediately after surgery. The tumors were then harvested from NOD/SCID mice and passed orthotopically in nude mice to make patient-derived orthotopic xenograft (PDOX) models. Eight weeks after orthotopic implantation, a monoclonal anti-carcinoembryonic antigen (CEA) antibody conjugated with AlexaFluor® 488 (Molecular Probes Inc., Eugene, OR) was delivered to the PDOX models as a single intravenous dose 24 hours before laparotomy. A hand-held portable fluorescence imaging device was used. Results: The primary tumor was clearly visible at laparotomy with the portable fluorescence imaging system. Frozen section microscopy of the resected specimen demonstrated that the anti-CEA antibody selectively labeled cancer cells in the colon cancer PDOX. The tumor was completely resected under fluorescence navigation. Histologic evaluation of the resected specimen demonstrated that cancer cells were not present in the margins, indicating successful tumor resection. The FGS animals remained tumor free for over 6 months. Conclusions: The results of the present report indicate that FGS using a fluorophore-conjugated anti-CEA antibody and portable imaging system improves efficacy of resection for CEA-positive colorectal cancer. These data provide the basis for clinical trials. PMID:24494971

  13. Prestack time imaging algorithm with simultaneous velocity estimation in hard rock environments

    NASA Astrophysics Data System (ADS)

    Tertyshnikov, Konstantin 12Bóna, Andrej 1Pevzner, Roman

    2014-09-01

    Reflection seismic imaging faces several difficulties in hard rock environments. One of them is the estimation of the propagation velocity of seismic waves. Therefore, imaging algorithms that do not require prior construction of a velocity model seem promising for such environments. In this paper we illustrate an application of prestack time migration, which does not require an input velocity model, to hard rock conditions, and we demonstrate its effectiveness on synthetic data. This approach is based on an estimation of local event slopes (horizontal slownesses) in common-shot and common-receiver gathers and a subsequent calculation of the migration attributes (migration velocity, vertical traveltime and horizontal coordinates of the migrated reflection point). These attributes allow us to derive all the information needed to construct a time-migrated image. We also use the obtained migration velocities as an input velocity model for Kirchhoff prestack time migration (PSTM) and compare the results of the proposed approach with a conventional Kirchhoff migration using as an input the picked NMO velocity model. This application to a hard rock synthetic model illustrates the potential of the presented migration algorithm for imaging in hard rock seismic exploration. We believe that this approach can be used in hard rock seismic processing workflows as an automatic tool to obtain an input velocity model for the Kirchhoff PSTM.

  14. Radiofluorinated derivatives of 2-(phosphonomethyl)pentanedioic acid as inhibitors of prostate specific membrane antigen (PSMA) for the imaging of prostate cancer.

    PubMed

    Graham, Keith; Lesche, Ralf; Gromov, Alexey V; Böhnke, Niels; Schäfer, Martina; Hassfeld, Jorma; Dinkelborg, Ludger; Kettschau, Georg

    2012-11-26

    For prostate cancer, prostate specific membrane antigen (PSMA) has been identified as a diagnostic and therapeutic target. Fluorinated derivatives of 2-(phosphonomethyl)pentanedioic acid were designed and synthesized to explore whether this fluorine-substituent is tolerated in the pentanedioic acid moiety that is common to almost all PSMA targeting small molecule inhibitors. The binding affinities of the racemic and individual stereoisomers of 2-fluoro-4-(phosphonomethyl)pentanedioic acid were determined and showed that the introduction of fluorine was well tolerated. The radiosynthesis of the analogous 2-[(18)F]fluoro-4-(phosphonomethyl)pentanedioic acid was developed and evaluated in vivo with the PSMA positive LNCaP human prostate cancer cell. The biological results demonstrated specific binding of the tracer to PSMA positive tumors in mice. These results warrant the further evaluation of this class of compounds as radiolabeled tracers for the detection and staging of prostate cancer. PMID:23025786

  15. Discrimination between glioblastoma multiforme and solitary metastasis using morphological features derived from the p:q tensor decomposition of diffusion tensor imaging.

    PubMed

    Yang, Guang; Jones, Timothy L; Barrick, Thomas R; Howe, Franklyn A

    2014-09-01

    The management and treatment of high-grade glioblastoma multiforme (GBM) and solitary metastasis (MET) are very different and influence the prognosis and subsequent clinical outcomes. In the case of a solitary MET, diagnosis using conventional radiology can be equivocal. Currently, a definitive diagnosis is based on histopathological analysis on a biopsy sample. Here, we present a computerised decision support framework for discrimination between GBM and solitary MET using MRI, which includes: (i) a semi-automatic segmentation method based on diffusion tensor imaging; (ii) two-dimensional morphological feature extraction and selection; and (iii) a pattern recognition module for automated tumour classification. Ground truth was provided by histopathological analysis from pre-treatment stereotactic biopsy or at surgical resection. Our two-dimensional morphological analysis outperforms previous methods with high cross-validation accuracy of 97.9% and area under the receiver operating characteristic curve of 0.975 using a neural networks-based classifier. PMID:25066520

  16. Characterization of the Campbell-Stokes sunshine duration recorder and its ability to derive direct solar radiation by using digital image processing

    NASA Astrophysics Data System (ADS)

    Sanchez-Romero, Alejandro; González, Josep-Abel; Calbó, Josep; Sanchez-Lorenzo, Arturo

    2014-05-01

    The World Meteorological Organization defines the sunshine duration (SD) as the time that, along a given period, direct solar irradiance (DSI) exceeds the threshold level of 120 W/m2. Since the end of 19th century, the Campbell-Stokes sunshine recorder (CSSR) has been the most commonly used instrument used for measuring SD. Due to the large number of long records that exist worldwide, valuable climatic information can be extracted from them. Many authors have used the daily SD (as obtained from the measurement of the length of burn for a given card) to obtain additional information about solar radiation, by using Ångström-Prescott type formulas. Contrarily, the burn width has not been systematically used. Theoretically, the burn is wider (narrower) when the direct insolation is stronger (weaker). The aim of this research is to show the relationship between burn width and DSI, and to prove whether this relationship depends on the type of CSSR and burning card. The research has been carried out in Girona (NE Spain) for a period of two years (from January 2012 to January 2014). Two different models of CSSR (which use different types of cards) and a pyrheliometer from Kipp&Zonen were used to measure SD and DSI, respectively. A semi-automatic method based on image processing of digital scanned images of burnt cards is presented. The method can be summarized in four steps: (i) scan each band on a green background; (ii) apply a digital process to increase the contrast of the burn; (iii) define two/three points in the image, depending of the geometry of the card, to point the center of the day (12.00 TST) on the image and define the trajectory of the sun with 1-minute intervals; and (iv) apply a program to make cross-sections every minute and measure the width of burn. So, after all of this process, we obtain a temporal evolution of the burn width with 1-minute resolution and distinguishing between morning and afternoon. The results show that there is a good correlation between the burn widths obtained from the two types of CSSR. We also observe a quite good correlation with DSI, which is consistent with our hypothesis. However, if we study the threshold value, we obtain a wide range of values that are almost always higher than 120 W/m2, with a significant difference between the morning and afternoon records. Consequently, we consider that the behaviour of cards may also depend on other meteorological variables (temperature, humidity…) affecting the burn. The physical characteristics of the heliograph and of the cardboard from which the bands are made may also have an important role in this relationship. The method was applied to a limited series of cards, but could offer a practical way to exploit the worldwide sets of long-term CSSR data to create long time series of DSI. As there are methods to extract atmospheric aerosol content based on DSI (Linke turbidity factor, Ångström's turbidity coefficient, etc.), SD may become a proxy measurement for turbidity and atmospheric aerosol loading since the late 19th century.

  17. Label-free, live optical imaging of reprogrammed bipolar disorder patient-derived cells reveals a functional correlate of lithium responsiveness

    PubMed Central

    Wang, J L; Shamah, S M; Sun, A X; Waldman, I D; Haggarty, S J; Perlis, R H

    2014-01-01

    Development of novel treatments and diagnostic tools for psychiatric illness has been hindered by the absence of cellular models of disease. With the advent of cellular reprogramming, it may be possible to recapitulate the disease biology of psychiatric disorders using patient skin cells transdifferentiated to neurons. However, efficiently identifying and characterizing relevant neuronal phenotypes in the absence of well-defined pathophysiology remains a challenge. In this study, we collected fibroblast samples from patients with bipolar 1 disorder, characterized by their lithium response (n=12), and healthy control subjects (n=6). We identified a cellular phenotype in reprogrammed neurons using a label-free imaging assay based on a nanostructured photonic crystal biosensor and found that an optical measure of cell adhesion was associated with clinical response to lithium treatment. This cellular phenotype may represent a useful biomarker to evaluate drug response and screen for novel therapeutics. PMID:25158003

  18. Development of Purine-Derived 18F-Labeled Pro-drug Tracers for Imaging of MRP1 Activity with PET

    PubMed Central

    2014-01-01

    Multidrug resistance-associated protein 1 (MRP1) is a drug efflux transporter that has been implicated in the pathology of several neurological diseases and is associated with development of multidrug resistance. To enable measurement of MRP1 function in the living brain, a series of 6-halopurines decorated with fluorinated side chains have been synthesized and evaluated as putative pro-drug tracers. The tracers were designed to undergo conjugation with glutathione within the brain and hence form the corresponding MRP1 substrate tracers in situ. 6-Bromo-7-(2-[18F]fluoroethyl)purine showed good brain uptake and rapid metabolic conversion. Dynamic PET imaging demonstrated a marked difference in brain clearance rates between wild-type and mrp1 knockout mice, suggesting that the tracer can allow noninvasive assessment of MRP1 activity in vivo. PMID:24456310

  19. Modular use of peripheral input channels tunes motion-detecting circuitry

    PubMed Central

    Silies, Marion; Gohl, Daryl M.; Fisher, Yvette E.; Freifeld, Limor; Clark, Damon A.; Clandinin, Thomas R.

    2013-01-01

    SUMMARY In the visual system, peripheral processing circuits are often tuned to specific stimulus features. How this selectivity arises and how these circuits are organized to inform specific visual behaviors is incompletely understood. Using forward genetics and quantitative behavioral studies, we uncover a new input channel to motion detecting circuitry in Drosophila. The second order neuron L3 acts combinatorially with two previously known inputs, L1 and L2, to inform circuits specialized to detect moving light and dark edges. In vivo calcium imaging of L3, combined with neuronal silencing experiments, suggests a neural mechanism to achieve selectivity for moving dark edges. We further demonstrate that different innate behaviors, turning and forward movement, can be independently modulated by visual motion. These two behaviors make use of different combinations of input channels. Such modular use of input channels to achieve feature extraction and behavioral specialization likely represents a general principle in sensory systems. PMID:23849199

  20. Long term functional plasticity of sensory inputs mediated by olfactory learning

    PubMed Central

    Abraham, Nixon M; Vincis, Roberto; Lagier, Samuel; Rodriguez, Ivan; Carleton, Alan

    2014-01-01

    Sensory inputs are remarkably organized along all sensory pathways. While sensory representations are known to undergo plasticity at the higher levels of sensory pathways following peripheral lesions or sensory experience, less is known about the functional plasticity of peripheral inputs induced by learning. We addressed this question in the adult mouse olfactory system by combining odor discrimination studies with functional imaging of sensory input activity in awake mice. Here we show that associative learning, but not passive odor exposure, potentiates the strength of sensory inputs up to several weeks after the end of training. We conclude that experience-dependent plasticity can occur in the periphery of adult mouse olfactory system, which should improve odor detection and contribute towards accurate and fast odor discriminations. DOI: http://dx.doi.org/10.7554/eLife.02109.001 PMID:24642413

  1. 5-Aminolevulinic Acid-derived Tumor Fluorescence: The Diagnostic Accuracy of Visible Fluorescence Qualities as Corroborated by Spectrometry and Histology and Postoperative Imaging

    PubMed Central

    Tonn, Jörg-Christian; Goetz, Claudia; Ullrich, Winfried; Stepp, Herbert; Bink, Andrea; Pietsch, Thorsten; Pichlmeier, Uwe

    2013-01-01

    BACKGROUND: 5-Aminolevulinic acid is used for fluorescence-guided resections. During resection, different macroscopic fluorescence qualities (“strong,” “weak”) can be distinguished that help guide resections. OBJECTIVE: This prospective study was designed to assess the reliability of visible fluorescence qualities by spectrometry, pathology, and imaging. METHODS: Thirty-three patients with malignant gliomas received 5-aminolevulinic acid (20 mg/kg). After debulking surgery, standardized biopsies were obtained from tissues with “weak” and “strong” fluorescence and from nonfluorescing near and distant brain for blinded assessment of cell density and tissue type (necrosis, solid or infiltrating tumor, normal tissue). The positive predictive value was calculated. Unresected fluorescing tissue was navigated for blinded correlation to postoperative magnetic resonance imaging (MRI). Receiver operating characteristic curves were generated for assessing the classification efficiency of spectrometry. RESULTS: “Strong” fluorescence corresponded to greater spectrometric fluorescence, solidly proliferating tumor, and high cell densities, whereas “weak” fluorescence corresponded to lower spectrometric fluorescence, infiltrating tumor, and medium cell densities. The positive predictive value was 100% in strongly fluorescing tissue and 95% in weakly fluorescing tissue. Spectrometric fluorescence was detected in marginal tissue without macroscopic fluorescence. Depending on the threshold, spectrometry displayed greater sensitivity but lower specificity (accuracy 88.4%). Residual MRI enhancement in the tumor bed was detected in 15 of 23 (65%) patients with residual fluorescence, but in none of the patients without residual fluorescence. CONCLUSION: Macroscopic fluorescence qualities predict solid and infiltrating tumor, providing useful information during resection. Fluorescence appears superior to contrast enhancement on MRI for indicating residual tumor. Spectrometry, on the other hand, is more sensitive but less specific, depending on threshold definition. ABBREVIATIONS: 5-ALA, 5-aminolevulinic acid CI, confidence interval gamma-GT, gamma-glutamyl transpeptidase GBM, glioblastoma multiforme NPV, negative predictive value PPIX, protoporphyrin IX PPV, positive predictive value SD, standard deviation WHO, World Health Organization PMID:24335821

  2. Level 2 processing for the imaging Fourier transform spectrometer GLORIA: derivation and validation of temperature and trace gas volume mixing ratios from calibrated dynamics mode spectra

    NASA Astrophysics Data System (ADS)

    Ungermann, J.; Blank, J.; Dick, M.; Ebersoldt, A.; Friedl-Vallon, F.; Giez, A.; Guggenmoser, T.; Höpfner, M.; Jurkat, T.; Kaufmann, M.; Kaufmann, S.; Kleinert, A.; Krämer, M.; Latzko, T.; Oelhaf, H.; Olchewski, F.; Preusse, P.; Rolf, C.; Schillings, J.; Suminska-Ebersoldt, O.; Tan, V.; Thomas, N.; Voigt, C.; Zahn, A.; Zöger, M.; Riese, M.

    2014-12-01

    The Gimballed Limb Observer for Radiance Imaging of the Atmosphere (GLORIA) is an airborne infrared limb-imager combining a two-dimensional infrared detector with a Fourier transform spectrometer. It was operated aboard the new German Gulfstream G550 research aircraft HALO during the Transport And Composition in the upper Troposphere/lowermost Stratosphere (TACTS) and Earth System Model Validation (ESMVAL) campaigns in summer 2012. This paper describes the retrieval of temperature and trace gas (H2O, O3, HNO3) volume mixing ratios from GLORIA dynamics mode spectra. 26 integrated spectral windows are employed in a joint fit to retrieve seven targets using consecutively a fast and an accurate tabulated radiative transfer model. Typical diagnostic quantities are provided including effects of uncertainties in the calibration and horizontal resolution along the line-of-sight. Simultaneous in-situ observations by the BAsic HALO Measurement And Sensor System (BAHAMAS), the Fast In-Situ Stratospheric Hygrometer (FISH), FAIRO, and the Atmospheric chemical Ionization Mass Spectrometer (AIMS) allow a validation of retrieved values for three flights in the upper troposphere/lowermost stratosphere region spanning polar and sub-tropical latitudes. A high correlation is achieved between the remote sensing and the in-situ trace gas data, and discrepancies can to a large fraction be attributed to differences in the probed air masses caused by different sampling characteristics of the instruments. This 1-D processing of GLORIA dynamics mode spectra provides the basis for future tomographic inversions from circular and linear flight paths to better understand selected dynamical processes of the upper troposphere and lowermost stratosphere.

  3. Clouds of Venus. Input to VIRA.

    NASA Astrophysics Data System (ADS)

    Ignatiev, Nikolay; Zasova, Ludmila

    2012-07-01

    Venus is completely covered by a thick clod deck. Its' total optical depth in the visible is equal to 30+/-10. Original VIRA model based on the measurements from Pioneer Venus descent probes and orbiter described mainly cloud particle sizes, properties and their vertical distribution. Later measurements from Venera-15 and Venus Express permitted more detailed studies of horizontal and vertical variations. Imaging of Venus in the UV range shows variety of cloud features that include mottled and streaky clouds in the low latitudes, bright mid-latitude belt and ``polar cap'' with imbedded oval polar dipole. Despite this non-uniform picture the location of the upper boundary of the clouds, derived from the observation of the absorption bands in the reflected IR spectrum, demonstrates a smooth systematic behavior with the latitudinal trends symmetric with respect to equator. In low and middle latitudes the cloud top is located at 72+/-1 km. It decreases poleward of +/-50 degrees and reaches 63--69 km in polar regions. This depression coincides with the eye of the planetary vortex. The effective average particle size radius is equal to (1.3+/-0.5) micron at latitudes of 0--70, with a peak value some 50% larger in the polar regions. Cloud top can experience fast variations of about metricconverterProductID1 km1 km in tens of hours, while larger long-term variations of several kilometers have been observed only at high latitudes. UV markings correlate with the cloud altimetry, however the difference between adjacent UV dark and bright regions never exceeds few hundred meters. Ultraviolet dark spiral arms, which are often seen at about --70 degress, correspond to higher altitudes or to the regions with strong latitudinal gradient of the cloud top altitude. In contrast to the relatively uniform upper cloud boundary, strong variations of the brightness temperature at specific near infrared wavelengths, especially in low latitudes, are related to variations of the cloud thickness in the middle and low cloud decks consistent with significant convective activity at these levels. The morphology of the holes tends from highly variable orientations of features with aspect ratios of nearly one at low latitudes, to very large aspect ratios and zonally oriented features at higher latitudes.

  4. Investigation of Effects of Varying Model Inputs on Mercury Deposition Estimates in the Southwest US

    EPA Science Inventory

    The Community Multiscale Air Quality (CMAQ) model version 4.7.1 was used to simulate mercury wet and dry deposition for a domain covering the continental United States (US). The simulations used MM5-derived meteorological input fields and the US Environmental Protection Agency (E...

  5. Chandrasekhar equations for infinite dimensional systems. Part 2: Unbounded input and output case

    NASA Technical Reports Server (NTRS)

    Ito, Kazufumi; Powers, Robert K.

    1987-01-01

    A set of equations known as Chandrasekhar equations arising in the linear quadratic optimal control problem is considered. In this paper, we consider the linear time-invariant system defined in Hilbert spaces involving unbounded input and output operators. For a general class of such systems, the Chandrasekhar equations are derived and the existence, uniqueness, and regularity of the results of their solutions established.

  6. A modified-forward multi-input power converter for solar energy and wind power generation

    Microsoft Academic Search

    Chih-Lung Shen; Cheng-Tao Tsai; Yu-En Wu; Chun-Chuan Chen

    2009-01-01

    In this paper a modified-forward multi-input converter (MFMIC) for renewable energy is proposed, which can not only process solar energy but deal with wind power. The proposed converter is derived from series forward structure to step down voltage for charger systems or dc distribution applications. The MFMIC mainly contains an upper forward, a lower forward, a common output inductor, and

  7. Modeling cancellation of periodic inputs with burst-STDP and feedback

    E-print Network

    Mejías, Jorge F.

    -like structure in wave-type electric fish. Our biologi- cally plausible mechanism is motivated by experimental-dependent learning rule, which in turn affects the feedback input and thus the burst rate. We show how the mean strength is also derived. Our results shed light on why bursts rather than single spikes can drive learning

  8. Influence of streamside vegetation on inputs of terrestrial invertebrates to salmonid food webs

    E-print Network

    Wagner, Diane

    Influence of streamside vegetation on inputs of terrestrial invertebrates to salmonid food webs J, and spawning migrations. We examined the contribution of terrestrially derived invertebrates (TI) to juvenile of invertebrate mass averaged across all sites; no significant differences associated with location (plant

  9. How to Generate Ordered Maps by Maximizing the Mutual Information between Input and Output Signals

    Microsoft Academic Search

    Ralph Linsker

    1989-01-01

    A learning rule that performs gradient ascent in the average mutual information between input and an output signal is derived for a system having feedforward and lateral interactions. Several processes emerge as components of this learning rule: Hebb-like modification, and cooperation and competition among processing nodes. Topographic map formation is demonstrated using the learning rule. An analytic expression relating the

  10. Defect detection in aluminum foil by input-estimate-based chi-square detector

    Microsoft Academic Search

    Ming Zhai; Zhongliang Jing; Shan Fu; Xinbin Luo

    2009-01-01

    Quality inspection of aluminum foil products plays an important role for aluminum foil manufactures. We present a method that uses input estimate (IE)-based chi-square detectors for defect detection in aluminum foil. It is assumed that the intensity of the aluminum foil image is Gaussian distributed, and the distribution of the defect intensity is different from the normal. Under these assumptions,

  11. The Evolution of Prefrontal Inputs to the Cortico-pontine System: Diffusion

    E-print Network

    Kastner, Sabine

    The Evolution of Prefrontal Inputs to the Cortico-pontine System: Diffusion Imaging Evidence from Macaque Monkeys and Humans Narender Ramnani1,2 , Timothy E.J. Behrens2 , Heidi Johansen-Berg2 , Marlene C and macaque monkeys. We confirm the dominant contribution of the cortical motor areas to the macaque monkey

  12. Lineaments derived from analysis of linear features mapped from Landsat images of the Four Corners region of the Southwestern United States

    USGS Publications Warehouse

    Knepper, Daniel H.

    1982-01-01

    Linear features are relatively short, distinct, non-cultural linear elements mappable on Landsat multispectral scanner images (MSS). Most linear features are related to local topographic features, such as cliffs, slope breaks, narrow ridges, and stream valley segments that are interpreted as reflecting directed aspects of local geologic structure including faults, zones of fracturing (joints), and the strike of tilted beds. 6,050 linear features were mapped on computer-enhanced Landsat MSS images of 11 Landsat scenes covering an area from the Rio Grande rift zone on the east to the Grand Canyon on the west and from the San Juan Mountains, Colorado, on the north to the Mogollon Rim on the south. Computer-aided statistical analysis of the linear feature data revealed 5 statistically important trend intervals: 1.) N. 10W.-N.16E., 2.) N.35-72E., 3.) N.33-59W., 4.) N. 74-83W., and 5.) N.89-9-W. and N. 89-90E. Subsequent analysis of the distribution of the linear features indicated that only the first three trend intervals are of regional geologic significance. Computer-generated maps of the linear features in each important trend interval were prepared, as well as contour maps showing the relative concentrations of linear features in each trend interval. These maps were then analyzed for patterns suggestive of possible regional tectonic lines. 20 possible tectonic lines, or lineaments, were interpreted from the maps. One lineament is defined by an obvious change in overall linear feature concentrations along a northwest-trending line cutting across northeastern Arizona. Linear features are abundant northeast of the line and relatively scarce to the southwest. The remaining 19 lineaments represent the axes of clusters of parallel linear features elongated in the direction of the linear feature trends. Most of these lineaments mark previously known structural zones controlled by linear features in the Precambrian basement or show newly recognized relationships to geological and/or geophysical patterns that suggest probable influence by buried basement features. The remaining few lineaments are not strongly correlative with geological or geophysical patterns, but on the basis of existing data they cannot be dismissed as being possible expressions of basement features.

  13. Image, Image, Image

    ERIC Educational Resources Information Center

    Howell, Robert T.

    2004-01-01

    With all the talk today about accountability, budget cuts, and the closing of programs in public education, teachers cannot overlook the importance of image in the field of industrial technology. It is very easy for administrators to cut ITE (industrial technology education) programs to save school money--money they might shift to teaching the…

  14. In vivo selective imaging and inhibition of leukemia stem-like cells using the fluorescent carbocyanine derivative, DiOC5(3).

    PubMed

    Zhang, Beibei; Shimada, Yasuhito; Kuroyanagi, Junya; Ariyoshi, Michiko; Nomoto, Tsuyoshi; Shintou, Taichi; Umemoto, Noriko; Nishimura, Yuhei; Miyazaki, Takeshi; Tanaka, Toshio

    2015-06-01

    Elimination of leukemia stem cells (LSCs) is necessary for the destruction of malignant cell populations. Owing to the very small number of LSCs in leukemia cells, xenotransplantation studies are difficult in terms of functionally and pathophysiologically replicating clinical conditions of cell culture experiments. There is currently a limited number of lead compounds that target LSCs. Using the LSC-xenograft zebrafish screening method we previously developed, we found that the fluorescent compound 3,3'-dipentyloxacarbocyanine iodide (DiOC5(3)) selectively marked LSCs and suppressed their proliferation in vivo and in vitro. DiOC5(3) had no obvious toxicity to human umbilical cord blood CD34+ progenitor cells and normal zebrafish. It accumulated in mitochondria through organic anion transporter polypeptides that are overexpressed in the plasma membrane of LSCs, and induced apoptosis via ROS overproduction. DiOC5(3) also inhibited the nuclear translocation of NF-?B through the downregulation of LSC-selective pathways, as indicated from DNA microarray analysis. In summary, DiOC5(3) is a new type of anti-LSC compound available for diagnostic imaging and therapeutics that has the advantage of being a single fluorescent chemical. PMID:25818410

  15. Comparative live bioluminescence imaging of monkeypox virus dissemination in a wild-derived inbred mouse (Mus musculus castaneus) and outbred African dormouse (Graphiurus kelleni).

    PubMed

    Earl, Patricia L; Americo, Jeffrey L; Cotter, Catherine A; Moss, Bernard

    2015-01-15

    Monkeypox virus belongs to the orthopoxvirus genus, infects rodents and monkeys in Africa, produces a smallpox-like zoonotic disease in humans, and has the potential for global spread and exploitation for bioterrorism. Several small animal models for studying monkeypox virus pathogenesis have been investigated. The African dormouse is a candidate natural host but is outbred and no immunological reagents exist. Although not a natural host, the CAST/EiJ mouse is inbred and animals and reagents are commercially available. We compared the dissemination of monkeypox virus by bioluminescence imaging in CAST/EiJ mice and dormice. In CAST/EiJ mice, intense replication occurred at the intranasal site of inoculation and virus spread rapidly to lungs and abdominal organs, which had a lower virus burden. Compared to CAST/EiJ mice, dormice exhibited a greater variation of virus spread, a slower time course, less replication in the head and chest, and more replication in abdominal organs prior to death. PMID:25462355

  16. Desert Dust Air Mass Mapping in the Western Sahara, using Particle Properties Derived from Space-based Multi-angle Imaging

    NASA Technical Reports Server (NTRS)

    Kahn, Ralph; Petzold, Andreas; Wendisch, Manfred; Bierwirth, Eike; Dinter, Tilman; Fiebig, Marcus; Schladitz, Alexander; von Hoyningen-Huene, Wolfgang

    2008-01-01

    Coincident observations made over the Moroccan desert during the SAhara Mineral dUst experiMent (SAMUM) 2006 field campaign are used both to validate aerosol amount and type retrieved from Multi-angle Imaging SpectroRadiometer (MISR) observations, and to place the sub-orbital aerosol measurements into the satellite's larger regional context. On three moderately dusty days for which coincident observations were made, MISR mid-visible aerosol optical thickness (AOT) agrees with field measurements point-by-point to within 0.05 to 0.1. This is about as well as can be expected given spatial sampling differences; the space-based observations capture AOT trends and variability over an extended region. The field data also validate MISR's ability to distinguish and to map aerosol air masses, from the combination of retrieved constraints on particle size, shape, and single-scattering albedo. For the three study days, the satellite observations (a) highlight regional gradients in the mix of dust and background spherical particles, (b) identify a dust plume most likely part of a density flow, and (c) show an air mass containing a higher proportion of small, spherical particles than the surroundings, that appears to be aerosol pollution transported from several thousand kilometers away.

  17. An evaluation of the variability of tumor-shape definition derived by experienced observers from CT images of supraglottic carcinomas (ACRIN protocol 6658)

    SciTech Connect

    Cooper, Jay S. [Department of Radiation Oncology, Maimonides Medical Center, Brooklyn, NY (United States)]. E-mail: jcooper@maimonidesmed.org; Mukherji, Suresh K. [Department of Radiology, University of Michigan Health System, Ann Arbor, MI (United States); Department of Otolaryngology Head Neck Surgery, University of Michigan Health System, Ann Arbor, MI (United States); Toledano, Alicia Y. [Center for Statistical Sciences, Brown University, Providence, RI (United States); Beldon, Clifford [Department of Radiology, State University of New York, Albany Medical School, Albany, NY (United States); Schmalfuss, Ilona M. [Department of Radiology, University of Florida School of Medicine, Gainesville, FL (United States); Amdur, Robert [Department of Radiation Oncology, University of Florida School of Medicine, Gainesville, FL (United States); Sailer, Scott [Department of Radiation Oncology, University of North Carolina School of Medicine, Chapel Hill, NC (United States); Loevner, Laurie A. [Department of Radiology, University of Pennsylvania School of Medicine, Philadelphia, PA (United States); Kousouboris, Phil [Department of Radiology, Bryn Mawr Hospital, Bryn Mawr, PA (United States); Ang, K. Kian [Department of Radiation Oncology, M. D. Anderson Cancer Center, Houston, TX (United States); Cormack, Jean [Center for Statistical Sciences, Brown University, Providence, RI (United States); Sicks, JoRean M.S. [Center for Statistical Sciences, Brown University, Providence, RI (United States)

    2007-03-15

    Purpose: Accurate target definition is considered essential for sophisticated, image-guided radiation therapy; however, relatively little information has been reported that measures our ability to identify the precise shape of targets accurately. We decided to assess the manner in which eight 'experts' interpreted the size and shape of tumors based on 'real-life' contrast-enhanced computed tomographic (CT) scans. Methods and Materials: Four neuroradiologists and four radiation oncologists (the authors) with considerable experience and presumed expertise in treating head-and-neck tumors independently contoured, slice-by-slice, his/her interpretation of the precise gross tumor volume (GTV) on each of 20 sets of CT scans taken from 20 patients who previously were enrolled in Radiation Therapy Oncology Group protocol 91-11. Results: The average proportion of overlap (i.e., the degree of agreement) was 0.532 (95% confidence interval 0.457 to 0.606). There was a slight tendency for the proportion of overlap to increase with increasing average GTV. Conclusions: Our work suggests that estimation of tumor shape currently is imprecise, even for experienced physicians. In consequence, there appears to be a practical limit to the current trend of smaller fields and tighter margins.

  18. Desert Dust Aerosol Air Mass Mapping in the Western Sahara, Using Particle Properties Derived from Space-Based Multi-Angle Imaging

    NASA Technical Reports Server (NTRS)

    Kahn, Ralph; Petzold, Andreas; Wendisch, Manfred; Bierwirth, Eike; Dinter, Tilman; Esselborn, Michael; Fiebig, Marcus; Heese, Birgit; Knippertz, Peter; Mueller, Detlef; Schladitz, Alexander; Von Hoyningen-Huene, Wolfgang

    2008-01-01

    Coincident observations made over the Moroccan desert during the Sahara mineral dust experiment (SAMUM) 2006 field campaign are used both to validate aerosol amount and type retrieved from multi-angle imaging spectroradiometer (MISR) observations, and to place the suborbital aerosol measurements into the satellite s larger regional context. On three moderately dusty days during which coincident observations were made, MISR mid-visible aerosol optical thickness (AOT) agrees with field measurements point-by-point to within 0.05 0.1. This is about as well as can be expected given spatial sampling differences; the space-based observations capture AOT trends and variability over an extended region. The field data also validate MISR s ability to distinguish and to map aerosol air masses, from the combination of retrieved constraints on particle size, shape and single-scattering albedo. For the three study days, the satellite observations (1) highlight regional gradients in the mix of dust and background spherical particles, (2) identify a dust plume most likely part of a density flow and (3) show an aerosol air mass containing a higher proportion of small, spherical particles than the surroundings, that appears to be aerosol pollution transported from several thousand kilometres away.

  19. FORMULAS FOR MODAL DENSITY AND FOR INPUT POWER FROM MECHANICAL AND FLUID POINT SOURCES IN FLUID FILLED PIPES

    Microsoft Academic Search

    S. Finnveden

    1997-01-01

    Simple expressions for the modal density of fluid filled pipes and for the input power from mechanical and fluid point sources are derived. The derivations are based on a previously reported, simplified theory for the radial–axial motion of fluid filled pipes. These equations are recapitulated and criteria for their application are given. The accuracy of the resulting expressions for modal

  20. Input-output characterization of fiber composites by SH waves

    NASA Technical Reports Server (NTRS)

    Renneisen, John D.; Williams, James H., Jr.

    1988-01-01

    Input-output characterization of fiber composites is studied theoretically by tracing SH waves in the media. A fiberglass epoxy composite is modeled as a homogeneous transversely isotropic continuum plate. The reflection of an SH wave at a stress-free plane boundary in a semi-infinite transversely isotropic medium is considered first. It is found that an incident SH wave reflects only a similar SH wave back into the medium. It is also established that the angle of reflection of the reflected wave is equal to the angle of incidence of the incident wave. The phase velocity of the SH waves and the delay time of the SH waves in reaching the receiving transducer are computed as functions of a reflection index, defined as the number of reflections of the SH waves from the bottom face of the continuum plate. The directivity function corresponding to the shear stress associated with the SH waves in the continuum plate is also derived as a function of the reflection index. A theoretical output voltage from the receiving transducer is calculated for a tone burst (a periodic input voltage of finite duration). The output voltage is shown for tone bursts of duration 60 microseconds and center frequencies of 0.75, 1.00, and 1.25 MHz. The study enhances the quantitative and qualitative understanding of the nondestructive evaluation (NDE) of fiber composites which can be modeled as transversely isotropic media.

  1. Multimodal interfaces with voice and gesture input

    SciTech Connect

    Milota, A.D.; Blattner, M.M.

    1995-07-20

    The modalities of speech and gesture have different strengths and weaknesses, but combined they create synergy where each modality corrects the weaknesses of the other. We believe that a multimodal system such a one interwining speech and gesture must start from a different foundation than ones which are based solely on pen input. In order to provide a basis for the design of a speech and gesture system, we have examined the research in other disciplines such as anthropology and linguistics. The result of this investigation was a taxonomy that gave us material for the incorporation of gestures whose meanings are largely transparent to the users. This study describes the taxonomy and gives examples of applications to pen input systems.

  2. Input on NIH Toolbox inclusion criteria

    PubMed Central

    Victorson, David; Debb, Scott M.; Gershon, Richard C.

    2013-01-01

    Objective: The NIH Toolbox is intended to be responsive to the needs of investigators evaluating neurologic and behavioral function in diverse settings. Early phases of the project involved gathering information and input from potential end users. Methods: Information was collected through literature and instrument database reviews, requests for information, consensus meetings, and expert interviews and integrated into the NIH Toolbox development process in an iterative manner. Results: Criteria for instrument inclusion, subdomains to be assessed, and preferences regarding instrument cost and length were obtained. Existing measures suitable for inclusion in the NIH Toolbox and areas requiring new measure development were identified. Conclusion: The NIH Toolbox was developed with explicit input from potential end users regarding many of its key features. PMID:23479548

  3. Controlling Synfire Chain by Inhibitory Synaptic Input

    NASA Astrophysics Data System (ADS)

    Shinozaki, Takashi; Câteau, Hideyuki; Urakubo, Hidetoshi; Okada, Masato

    2007-04-01

    The propagation of highly synchronous firings across neuronal networks, called the synfire chain, has been actively studied both theoretically and experimentally. The temporal accuracy and remarkable stability of the propagation have been repeatedly examined in previous studies. However, for such a mode of signal transduction to play a major role in processing information in the brain, the propagation should also be controlled dynamically and flexibly. Here, we show that inhibitory but not excitatory input can bidirectionally modulate the propagation, i.e., enhance or suppress the synchronous firings depending on the timing of the input. Our simulations based on the Hodgkin-Huxley neuron model demonstrate this bidirectional modulation and suggest that it should be achieved with any biologically inspired modeling. Our finding may help describe a concrete scenario of how multiple synfire chains lying in a neuronal network are appropriately controlled to perform significant information processing.

  4. Interactive specification and acquisition of depth from single images

    E-print Network

    Chen, Max, 1977-

    2001-01-01

    We describe a system for interactively acquiring depth for an image-based representation consisting of a single input image. We use layers of images with depth to represent the scene. Unlike traditional 3D modeling and ...

  5. Synthetic Fingerprint-Image Generation

    Microsoft Academic Search

    Raffaele Cappelli; Dario Maio; Davide Maltoni; Ali Erol

    2000-01-01

    Introduces a method for the generation of synthetic fingerprint images. Gabor-like space-variant filters are used for iteratively expanding an initially empty image containing just one or a few seeds. A directional image model, whose inputs are the number and location of the fingerprint cores and deltas, is used for tuning the filters according to the underlying ridge orientation. Very realistic

  6. Apple Image Processing Educator

    NASA Technical Reports Server (NTRS)

    Gunther, F. J.

    1981-01-01

    A software system design is proposed and demonstrated with pilot-project software. The system permits the Apple II microcomputer to be used for personalized computer-assisted instruction in the digital image processing of LANDSAT images. The programs provide data input, menu selection, graphic and hard-copy displays, and both general and detailed instructions. The pilot-project results are considered to be successful indicators of the capabilities and limits of microcomputers for digital image processing education.

  7. Optimum employment of satellite indirect soundings as numerical model input

    NASA Technical Reports Server (NTRS)

    Horn, L. H.; Derber, J. C.; Koehler, T. L.; Schmidt, B. D.

    1981-01-01

    The characteristics of satellite-derived temperature soundings that would significantly affect their use as input for numerical weather prediction models were examined. Independent evaluations of satellite soundings were emphasized to better define error characteristics. Results of a Nimbus-6 sounding study reveal an underestimation of the strength of synoptic scale troughs and ridges, and associated gradients in isobaric height and temperature fields. The most significant errors occurred near the Earth's surface and the tropopause. Soundings from the TIROS-N and NOAA-6 satellites were also evaluated. Results again showed an underestimation of upper level trough amplitudes leading to weaker thermal gradient depictions in satellite-only fields. These errors show a definite correlation to the synoptic flow patterns. In a satellite-only analysis used to initialize a numerical model forecast, it was found that these synoptically correlated errors were retained in the forecast sequence.

  8. On the input of a measurement process

    NASA Astrophysics Data System (ADS)

    Mari, Luca; Giordani, Alessandro

    2015-02-01

    It is assumed sometimes that the input of a measurement, and therefore the entity with which a measuring system interacts, is a quantity value, possibly the (true) measurand value, and from this hypothesis the model of ideal measurement as an identity process is formulated. In this paper we show that this position is based on an inappropriate superposition of quantities and quantity values, and therefore should be discarded.

  9. Three-dimensional data input by tablet

    Microsoft Academic Search

    IVAN E. SUTHERLAND

    1974-01-01

    A large-area multiple-pen tablet system for three-dimensional data input is described. The large tablet area provides space for simultaneous use of several views of the three-dimensional object being digitized. The multiple pens enable the user to indicate a single point simultaneously in two such views, thus defining the three-dimensional position of the point. Five significant techniques are outlined. First, the

  10. Generalized Input-Output Inequality Systems

    SciTech Connect

    Liu Yingfan [Department of Mathematics, Nanjing University of Post and Telecommunications, Nanjing 210009 (China)], E-mail: yingfanliu@hotmail.com; Zhang Qinghong [Department of Mathematics and Computer Science, Northern Michigan University, Marquette, MI 49855 (United States)], E-mail: qzhang@nmu.edu

    2006-09-15

    In this paper two types of generalized Leontief input-output inequality systems are introduced. The minimax properties for a class of functions associated with the inequalities are studied. Sufficient and necessary conditions for the inequality systems to have solutions are obtained in terms of the minimax value. Stability analysis for the solution set is provided in terms of upper semi-continuity and hemi-continuity of set-valued maps.

  11. Sensory synergy as environmental input integration

    PubMed Central

    Alnajjar, Fady; Itkonen, Matti; Berenz, Vincent; Tournier, Maxime; Nagai, Chikara; Shimoda, Shingo

    2015-01-01

    The development of a method to feed proper environmental inputs back to the central nervous system (CNS) remains one of the challenges in achieving natural movement when part of the body is replaced with an artificial device. Muscle synergies are widely accepted as a biologically plausible interpretation of the neural dynamics between the CNS and the muscular system. Yet the sensorineural dynamics of environmental feedback to the CNS has not been investigated in detail. In this study, we address this issue by exploring the concept of sensory synergy. In contrast to muscle synergy, we hypothesize that sensory synergy plays an essential role in integrating the overall environmental inputs to provide low-dimensional information to the CNS. We assume that sensor synergy and muscle synergy communicate using these low-dimensional signals. To examine our hypothesis, we conducted posture control experiments involving lateral disturbance with nine healthy participants. Proprioceptive information represented by the changes on muscle lengths were estimated by using the musculoskeletal model analysis software SIMM. Changes on muscles lengths were then used to compute sensory synergies. The experimental results indicate that the environmental inputs were translated into the two dimensional signals and used to move the upper limb to the desired position immediately after the lateral disturbance. Participants who showed high skill in posture control were found to be likely to have a strong correlation between sensory and muscle signaling as well as high coordination between the utilized sensory synergies. These results suggest the importance of integrating environmental inputs into suitable low-dimensional signals before providing them to the CNS. This mechanism should be essential when designing the prosthesis' sensory system to make the controller simpler. PMID:25628523

  12. Minimizing structural vibrations with Input Shaping (TM)

    NASA Technical Reports Server (NTRS)

    Singhose, Bill; Singer, Neil

    1995-01-01

    A new method for commanding machines to move with increased dynamic performance was developed. This method is an enhanced version of input shaping, a patented vibration suppression algorithm. This technique intercepts a command input to a system command that moves the mechanical system with increased performance and reduced residual vibration. This document describes many advanced methods for generating highly optimized shaping sequences which are tuned to particular systems. The shaping sequence is important because it determines the trade off between move/settle time of the system and the insensitivity of the input shaping algorithm to variations or uncertainties in the machine which can be controlled. For example, a system with a 5 Hz resonance that takes 1 second to settle can be improved to settle instantaneously using a 0.2 shaping sequence (thus improving settle time by a factor of 5). This system could vary by plus or minus 15% in its natural frequency and still have no apparent vibration. However, the same system shaped with a 0.3 second shaping sequence could tolerate plus or minus 40% or more variation in natural frequency. This document describes how to generate sequences that maximize performance, sequences that maximize insensitivity, and sequences that trade off between the two. Several software tools are documented and included.

  13. An in situ approach to detect tree root ecology: linking ground-penetrating radar imaging to isotope-derived water acquisition zones.

    PubMed

    Isaac, Marney E; Anglaaere, Luke C N

    2013-05-01

    Tree root distribution and activity are determinants of belowground competition. However, studying root response to environmental and management conditions remains logistically challenging. Methodologically, nondestructive in situ tree root ecology analysis has lagged. In this study, we tested a nondestructive approach to determine tree coarse root architecture and function of a perennial tree crop, Theobroma cacao L., at two edaphically contrasting sites (sandstone and phyllite-granite derived soils) in Ghana, West Africa. We detected coarse root vertical distribution using ground-penetrating radar and root activity via soil water acquisition using isotopic matching of ?(18)O plant and soil signatures. Coarse roots were detected to a depth of 50 cm, however, intraspecifc coarse root vertical distribution was modified by edaphic conditions. Soil ?(18)O isotopic signature declined with depth, providing conditions for plant-soil ?(18)O isotopic matching. This pattern held only under sandstone conditions where water acquisition zones were identifiably narrow in the 10-20 cm depth but broader under phyllite-granite conditions, presumably due to resource patchiness. Detected coarse root count by depth and measured fine root density were strongly correlated as were detected coarse root count and identified water acquisition zones, thus validating root detection capability of ground-penetrating radar, but exclusively on sandstone soils. This approach was able to characterize trends between intraspecific root architecture and edaphic-dependent resource availability, however, limited by site conditions. This study successfully demonstrates a new approach for in situ root studies that moves beyond invasive point sampling to nondestructive detection of root architecture and function. We discuss the transfer of such an approach to answer root ecology questions in various tree-based landscapes. PMID:23762519

  14. An in situ approach to detect tree root ecology: linking ground-penetrating radar imaging to isotope-derived water acquisition zones

    PubMed Central

    Isaac, Marney E; Anglaaere, Luke C N

    2013-01-01

    Tree root distribution and activity are determinants of belowground competition. However, studying root response to environmental and management conditions remains logistically challenging. Methodologically, nondestructive in situ tree root ecology analysis has lagged. In this study, we tested a nondestructive approach to determine tree coarse root architecture and function of a perennial tree crop, Theobroma cacao L., at two edaphically contrasting sites (sandstone and phyllite–granite derived soils) in Ghana, West Africa. We detected coarse root vertical distribution using ground-penetrating radar and root activity via soil water acquisition using isotopic matching of ?18O plant and soil signatures. Coarse roots were detected to a depth of 50 cm, however, intraspecifc coarse root vertical distribution was modified by edaphic conditions. Soil ?18O isotopic signature declined with depth, providing conditions for plant–soil ?18O isotopic matching. This pattern held only under sandstone conditions where water acquisition zones were identifiably narrow in the 10–20 cm depth but broader under phyllite–granite conditions, presumably due to resource patchiness. Detected coarse root count by depth and measured fine root density were strongly correlated as were detected coarse root count and identified water acquisition zones, thus validating root detection capability of ground-penetrating radar, but exclusively on sandstone soils. This approach was able to characterize trends between intraspecific root architecture and edaphic-dependent resource availability, however, limited by site conditions. This study successfully demonstrates a new approach for in situ root studies that moves beyond invasive point sampling to nondestructive detection of root architecture and function. We discuss the transfer of such an approach to answer root ecology questions in various tree-based landscapes. PMID:23762519

  15. Writing to your car: handwritten text input while driving

    Microsoft Academic Search

    Dagmar Kern; Albrecht Schmidt; Jonas Arnsmann; Thorsten Appelmann; Nillakshi Pararasasegaran; Benjamin Piepiera

    2009-01-01

    For in-car navigation, information and entertainment systems, text input is increasingly important. We investigate handwriting as a text input modality and assess where to best position the input surface and how to provide feedback. For this purpose, we created different prototypes that allow text input on the steering wheel and in the central console, as well as visual feedback on

  16. Inadvertent Intruder Analysis Input for Radiological Performance Assessments

    SciTech Connect

    LEE, PATRICIAL.

    2004-07-22

    This report describes and identifies input parameter values used for the hypothetical inadvertent intruder analyses for Radiological PAs at SRS. It is intended to describe and document the input parameters residing in the input file Intruder input of the intruder analysis application developed by Koffman (2004).

  17. Effective feature selection for image steganalysis using extreme learning machine

    NASA Astrophysics Data System (ADS)

    Feng, Guorui; Zhang, Haiyan; Zhang, Xinpeng

    2014-11-01

    Image steganography delivers secret data by slight modifications of the cover. To detect these data, steganalysis tries to create some features to embody the discrepancy between the cover and steganographic images. Therefore, the urgent problem is how to design an effective classification architecture for given feature vectors extracted from the images. We propose an approach to automatically select effective features based on the well-known JPEG steganographic methods. This approach, referred to as extreme learning machine revisited feature selection (ELM-RFS), can tune input weights in terms of the importance of input features. This idea is derived from cross-validation learning and one-dimensional (1-D) search. While updating input weights, we seek the energy decreasing direction using the leave-one-out (LOO) selection. Furthermore, we optimize the 1-D energy function instead of directly discarding the least significant feature. Since recent Liu features can gain considerable low detection errors compared to a previous JPEG steganalysis, the experimental results demonstrate that the new approach results in less classification error than other classifiers such as SVM, Kodovsky ensemble classifier, direct ELM-LOO learning, kernel ELM, and conventional ELM in Liu features. Furthermore, ELM-RFS achieves a similar performance with a deep Boltzmann machine using less training time.

  18. Motion-gated acquisition for in vivo optical imaging

    PubMed Central

    Gioux, Sylvain; Ashitate, Yoshitomo; Hutteman, Merlijn; Frangioni, John V.

    2009-01-01

    Wide-field continuous wave fluorescence imaging, fluorescence lifetime imaging, frequency domain photon migration, and spatially modulated imaging have the potential to provide quantitative measurements in vivo. However, most of these techniques have not yet been successfully translated to the clinic due to challenging environmental constraints. In many circumstances, cardiac and respiratory motion greatly impair image quality and?or quantitative processing. To address this fundamental problem, we have developed a low-cost, field-programmable gate array–based, hardware-only gating device that delivers a phase-locked acquisition window of arbitrary delay and width that is derived from an unlimited number of pseudo-periodic and nonperiodic input signals. All device features can be controlled manually or via USB serial commands. The working range of the device spans the extremes of mouse electrocardiogram (1000 beats per minute) to human respiration (4 breaths per minute), with timing resolution ?0.06%, and jitter ?0.008%, of the input signal period. We demonstrate the performance of the gating device, including dramatic improvements in quantitative measurements, in vitro using a motion simulator and in vivo using near-infrared fluorescence angiography of beating pig heart. This gating device should help to enable the clinical translation of promising new optical imaging technologies. PMID:20059276

  19. Quantum Hilbert Image Scrambling

    NASA Astrophysics Data System (ADS)

    Jiang, Nan; Wang, Luo; Wu, Wen-Ya

    2014-07-01

    Analogies between quantum image processing (QIP) and classical one indicate that quantum image scrambling (QIS), as important as quantum Fourier transform (QFT), quantum wavelet transform (QWT) and etc., should be proposed to promote QIP. Image scrambling technology is commonly used to transform a meaningful image into a disordered image by permutating the pixels into new positions. Although image scrambling on classical computers has been widely studied, we know much less about QIS. In this paper, the Hilbert image scrambling algorithm, which is commonly used in classical image processing, is carried out in quantum computer by giving the scrambling quantum circuits. First, a modified recursive generation algorithm of Hilbert scanning matrix is given. Then based on the flexible representation of quantum images, the Hilbert scrambling quantum circuits, which are recursive and progressively layered, is proposed. Theoretical analysis indicates that the network complexity scales squarely with the size of the circuit's input n.

  20. [(68)Ga]FSC-(RGD)3 a trimeric RGD peptide for imaging ?v?3 integrin expression based on a novel siderophore derived chelating scaffold-synthesis and evaluation.

    PubMed

    Knetsch, Peter A; Zhai, Chuangyan; Rangger, Christine; Blatzer, Michael; Haas, Hubertus; Kaeopookum, Piriya; Haubner, Roland; Decristoforo, Clemens

    2015-02-01

    Over the last years Gallium-68 ((68)Ga) has received tremendous attention for labeling of radiopharmaceuticals for positron emission tomography (PET). (68)Ga labeling of biomolecules is currently based on bifunctional chelators containing aminocarboxylates (mainly DOTA and NOTA). We have recently shown that cyclic peptide siderophores have very good complexing properties for (68)Ga resulting in high specific activities and excellent metabolic stabilities, in particular triacetylfusarinine-C (TAFC). We postulated, that, starting from its deacetylated form (Fusarinine-C (FSC)) trimeric bioconjugates are directly accessible to develop novel targeting peptide based (68)Ga labeled radiopharmaceuticals. As proof of principle we report on the synthesis and (68)Ga-radiolabeling of a trimeric FSC-RGD conjugate, [(68)Ga]FSC-(RGD)3, targeting ?v?3 integrin, which is highly expressed during tumor-induced angiogenesis. Synthesis of the RGD peptide was carried out applying solid phase peptide synthesis (SPPS), followed by the coupling to the siderophore [Fe]FSC via in situ activation using HATU/HOAt and DIPEA. Subsequent demetalation allowed radiolabeling of FSC-(RGD)3 with (68)Ga. The radiolabeling procedure was optimized regarding peptide amount, reaction time, temperature as well buffer systems. For in vitro evaluation partition coefficient, protein binding, serum stability, ?v?3 integrin binding affinity, and tumor cell uptake were determined. For in vitro tests as well as for the biodistribution studies ?v?3 positive human melanoma M21 and ?v?3 negative M21-L cells were used. [(68)Ga]FSC-(RGD)3 was prepared with high radiochemical yield (>98%). Distribution coefficient was -3.6 revealing a hydrophilic character, and an IC50 value of 1.8±0.6 nM was determined indicating a high binding affinity for ?v?3 integrin. [(68)Ga]FSC-(RGD)3 was stable in PBS (pH7.4), FeCl3- and DTPA-solution as well as in fresh human serum at 37°C for 2hours. Biodistribution assay confirmed the receptor specific uptake found in vitro. Uptake in the ?v?3 positive tumor was 4.3% ID/g 60min p.i. which was 3-fold higher than the monomeric [(68)Ga]NODAGA-RGD. Tumor to blood ratio of approx. 8 and tumor to muscle ratio of approx. 7 were observed. [(68)Ga]FSC-(RGD)3 serves as an example for the feasibility of a novel class of bifunctional chelators based on cyclic peptide siderophores and shows excellent targeting properties for ?v?3 integrin in vivo for imaging tumor-induced neovascularization. PMID:25459110