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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. A method of generating image derived input function in quantitative 18F-FDG PET study based on the monotonicity of the input and output function curve

    PubMed Central

    Zhou, Shan; Chen, Kewei; Reiman, Eric M; Li, De-min; Shan, Baoci

    2013-01-01

    Objective A method for defining image-derived input function (IDIF) has been introduced and evaluated for the quantification of the regional cerebral metabolic rate of glucose in positron emission tomography studies. Methods The voxels in the brain vasculature are extracted based on the different monotonicity between the input and output function curves. The TACs of such voxels are averaged to get the uncorrected TAC of the brain vasculature. The IDIF was obtained from the raw TAC after correcting for the partial volume and spillover effects by an empirical formula in conjunction with single blood sample and the TAC of the brain tissue. Data from 16 human subjects were used to test the proposed method. The Patlak approach is used to calculate the net FDG clearance with plasma-derived input function (PDIF) and our generated IDIF, respectively. Results the net FDG clearances calculated with the image-derived input function generated by our approach are not only highly correlated (correlation coefficients close to 1) to, but also highly comparable (regression slopes close to 1, and intercepts close to 0) with those calculated with plasma-derived input function. Conclusion The method used in the present work is feasible and accurate. PMID:22262245

  3. Combining MRI with PET for partial volume correction improves image-derived input functions in mice

    PubMed Central

    Evans, Eleanor; Buonincontri, Guido; Izquierdo, David; Methner, Carmen; Hawkes, Rob C.; Ansorge, Richard E.; Krieg, Thomas; Carpenter, T. Adrian; Sawiak, Stephen J.

    2015-01-01

    Accurate kinetic modelling using dynamic PET requires knowledge of the tracer concentration in plasma, known as the arterial input function (AIF). AIFs are usually determined by invasive blood sampling, but this is prohibitive in murine studies due to low total blood volumes. As a result of the low spatial resolution of PET, image-derived input functions (IDIFs) must be extracted from left ventricular blood pool (LVBP) ROIs of the mouse heart. This is challenging because of partial volume and spillover effects between the LVBP and myocardium, contaminating IDIFs with tissue signal. We have applied the geometric transfer matrix (GTM) method of partial volume correction (PVC) to 12 mice injected with 18F-FDG affected by a Myocardial Infarction (MI), of which 6 were treated with a drug which reduced infarction size [1]. We utilised high resolution MRI to assist in segmenting mouse hearts into 5 classes: LVBP, infarcted myocardium, healthy myocardium, lungs/body and background. The signal contribution from these 5 classes was convolved with the point spread function (PSF) of the Cambridge split magnet PET scanner and a non-linear fit was performed on the 5 measured signal components. The corrected IDIF was taken as the fitted LVBP component. It was found that the GTM PVC method could recover an IDIF with less contamination from spillover than an IDIF extracted from PET data alone. More realistic values of Ki were achieved using GTM IDIFs, which were shown to be significantly different (p<0.05) between the treated and untreated groups. PMID:26213413

  4. Image-derived input function obtained in a 3TMR-brainPET

    NASA Astrophysics Data System (ADS)

    da Silva, N. A.; Herzog, H.; Weirich, C.; Tellmann, L.; Rota Kops, E.; Hautzel, H.; Almeida, P.

    2013-02-01

    Aim: The combination of a high-resolution MR-compatible BrainPET insert operated within a 3 T MAGNETOM Trio MR scanner is an excellent tool for obtaining an image derived input function (IDIF), due to simultaneous imaging. In this work, we explore the possibility of obtaining an IDIF from volumes of interest (VOI) defined over the carotid arteries (CAs) using the MR data. Material and methods: FDG data from three patients without brain disorders were included. VOIs were drawn bilaterally over the CAs on a MPRAGE image using a 50% isocontour (MR50VOI). CA PET/MR co-registration was examined based on an individual and combined CA co-registration. After that, to estimate the IDIF, the MR50VOI average (IDIF-A), four hottest pixels per plane (IDIF-4H) and four hottest pixels in VOI (IDIF-4V) were considered. A model-based correction for residual partial volume effects involving venous blood samples was applied, from which partial volume (PV) and spillover (SP) coefficients were estimated. Additionally, a theoretical PV coefficient (PVt) was calculated based on MR50VOI. Results: The results show an excellent co-registration between the MR and PET, with an area under the curve ratio between both co-registration methods of 1.00±0.04. A good agreement between PV and PVt was found for IDIF-A, with PV of 0.39±0.06 and PVt 0.40±0.03, and for IDIF-4H, with PV of 0.47±0.05 and PVt 0.47±0.03. The SPs were 0.20±0.03 and 0.21±0.03 for IDIF-A and IDIF-4H, respectively. Conclusion: The integration of a high resolution BrainPET in an MR scanner allows to obtain an IDIF from an MR-based VOI. This must be corrected for a residual partial volume effect.

  5. 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.

  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. Image-derived and arterial blood sampled input functions for quantitative PET imaging of the angiotensin II subtype 1 receptor in the kidney

    SciTech Connect

    Feng, Tao; Tsui, Benjamin M. W.; Li, Xin; Vranesic, Melin; Lodge, Martin A.; Gulaldi, Nedim C. M.; Szabo, Zsolt

    2015-11-15

    Purpose: The radioligand {sup 11}C-KR31173 has been introduced for positron emission tomography (PET) imaging of the angiotensin II subtype 1 receptor in the kidney in vivo. To study the biokinetics of {sup 11}C-KR31173 with a compartmental model, the input function is needed. Collection and analysis of arterial blood samples are the established approach to obtain the input function but they are not feasible in patients with renal diseases. The goal of this study was to develop a quantitative technique that can provide an accurate image-derived input function (ID-IF) to replace the conventional invasive arterial sampling and test the method in pigs with the goal of translation into human studies. Methods: The experimental animals were injected with [{sup 11}C]KR31173 and scanned up to 90 min with dynamic PET. Arterial blood samples were collected for the artery derived input function (AD-IF) and used as a gold standard for ID-IF. Before PET, magnetic resonance angiography of the kidneys was obtained to provide the anatomical information required for derivation of the recovery coefficients in the abdominal aorta, a requirement for partial volume correction of the ID-IF. Different image reconstruction methods, filtered back projection (FBP) and ordered subset expectation maximization (OS-EM), were investigated for the best trade-off between bias and variance of the ID-IF. The effects of kidney uptakes on the quantitative accuracy of ID-IF were also studied. Biological variables such as red blood cell binding and radioligand metabolism were also taken into consideration. A single blood sample was used for calibration in the later phase of the input function. Results: In the first 2 min after injection, the OS-EM based ID-IF was found to be biased, and the bias was found to be induced by the kidney uptake. No such bias was found with the FBP based image reconstruction method. However, the OS-EM based image reconstruction was found to reduce variance in the subsequent phase of the ID-IF. The combined use of FBP and OS-EM resulted in reduced bias and noise. After performing all the necessary corrections, the areas under the curves (AUCs) of the AD-IF were close to that of the AD-IF (average AUC ratio =1 ± 0.08) during the early phase. When applied in a two-tissue-compartmental kinetic model, the average difference between the estimated model parameters from ID-IF and AD-IF was 10% which was within the error of the estimation method. Conclusions: The bias of radioligand concentration in the aorta from the OS-EM image reconstruction is significantly affected by radioligand uptake in the adjacent kidney and cannot be neglected for quantitative evaluation. With careful calibrations and corrections, the ID-IF derived from quantitative dynamic PET images can be used as the input function of the compartmental model to quantify the renal kinetics of {sup 11}C-KR31173 in experimental animals and the authors intend to evaluate this method in future human studies.

  8. 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.

  9. 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.

  10. Fuzzy Vision: Multiple Inputs Speed Image Understanding

    NASA Astrophysics Data System (ADS)

    Meier, Robert J.

    1985-12-01

    Fuzzy Vision is an architecture being considered at Nasa for the interpretation of multiple successive images. Its goal is the development of a system that can accept a sequence of images from several sensors, and update an image interpretation fast enough to direct an autonomous vehicle. Fuzzy Vision is relatively noise insensitive, and can be mapped directly onto parallel procesing hardware using the Grundy [1] parallel processing system. Fuzzy Vision breaks the image interpretation problem into two distinct subsystems that access a semantic net [2] called the region structure. The sensors and a set of masks (arbitrary functions) comprise the first subsystem called the region generator. The region generator updates the values in the semantic net. The interconnectivity of the region structure is fixed, but the information stored at the nodes and links is altered. The second subystem is an expert system called the viewer that produces the object list which is the system output. The two subsystems operate asynchronously. The Fuzzy Visionarchitecture accepts several technologies and component implementations. The region generator can comprise slow scan cameras, ordinary cameras, radars, operator input, and other sensor input. Likewise, the viewer consists of several cooperating expert systems operating asynchronously. If noise is added to the picture, only the data in the region structure is altered, the stability of the viewer is not affected, and noise insensitivity is achieved. Since the region structure is specified, the viewer can be simpler than the expert systems usually used. Local autonomous navigation (under 10m) is too close for practical use of radar, and most laser techniques require cooperation from the target. Malfunctioning satellites or those built without reflectors cannot be easily serviced. A vision system that can interpret raster images into a list of objects in real time would allow autonomous astrogation in close quarters or perhaps on another satellite. A computer or remote operator can interrogate Fuzzy Vision, reducing bandwidth requirements by a factor of 1 million or more. There has been success with current vision understanding systems such as ACRONYM [3], but these systems, require large periods of time (hours) to analyze a simple image, will not accept data from other sources such as radar, and are often unstable in the presence of noise.

  11. PRINCIPLES OF TOMOGRAPHICAL IMAGING WITH LIMITED-ANGLE INPUT

    SciTech Connect

    Tam, K. C.; Perez-Mendez, V.

    1980-09-01

    The theory of tomographical imaging with limited-angular input is discussed , from which two reconstruction algorithms are derived. The existence of missing information due to incomplete angular coverage is demonstrated. and an iteration algorithm to recover this information from a priori knowledge on the finite extent of the object developed. Smoothing algorithms to stabilize reconstructions in the presence of noise are given. The effects of digitization and finite truncation of the reconstruction region in numerical computation are also analysed. It is shown that the limited-angle problem is governed by a set of eigenvalues whose spectrum is determined by the imaging angle and the finite extent of the object. The distortion on a point source caused by the missing information is calculated; from the results some properties of the iteration scheme, such as spatial uniformity, are derived.

  12. Fuzzy vision - Multiple inputs speed image understanding

    NASA Technical Reports Server (NTRS)

    Meier, R. J., Jr.

    1985-01-01

    The fuzzy vision system designed for the interpretation of multiple successive images is described. The system is noise insensitive and can be mapped directly onto parallel processing hardware. The system consists of a region generator and a viewer which access a common semantic net; the components and operation of these subsystems are examined. The advantages and disadvantages of the fuzzy vision system are discussed. Diagrams of the region generator, viewer, and a semantic net are provided. An example depicting the operation of the fuzzy vision system is presented.

  13. 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.

  14. Robust image retrieval from noisy inputs using lattice associative memories

    NASA Astrophysics Data System (ADS)

    Urcid, Gonzalo; Nieves-V., José Angel; García-A., Anmi; Valdiviezo-N., Juan Carlos

    2009-02-01

    Lattice associative memories also known as morphological associative memories are fully connected feedforward neural networks with no hidden layers, whose computation at each node is carried out with lattice algebra operations. These networks are a relatively recent development in the field of associative memories that has proven to be an alternative way to work with sets of pattern pairs for which the storage and retrieval stages use minimax algebra. Different associative memory models have been proposed to cope with the problem of pattern recall under input degradations, such as occlusions or random noise, where input patterns can be composed of binary or real valued entries. In comparison to these and other artificial neural network memories, lattice algebra based memories display better performance for storage and recall capability; however, the computational techniques devised to achieve that purpose require additional processing or provide partial success when inputs are presented with undetermined noise levels. Robust retrieval capability of an associative memory model is usually expressed by a high percentage of perfect recalls from non-perfect input. The procedure described here uses noise masking defined by simple lattice operations together with appropriate metrics, such as the normalized mean squared error or signal to noise ratio, to boost the recall performance of either the min or max lattice auto-associative memories. Using a single lattice associative memory, illustrative examples are given that demonstrate the enhanced retrieval of correct gray-scale image associations from inputs corrupted with random noise.

  15. 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.

  16. 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.

  17. The effect of input data transformations on object-based image analysis

    PubMed Central

    LIPPITT, CHRISTOPHER D.; COULTER, LLOYD L.; FREEMAN, MARY; LAMANTIA-BISHOP, JEFFREY; PANG, WYSON; STOW, DOUGLAS A.

    2011-01-01

    The effect of using spectral transform images as input data on segmentation quality and its potential effect on products generated by object-based image analysis are explored in the context of land cover classification in Accra, Ghana. Five image data transformations are compared to untransformed spectral bands in terms of their effect on segmentation quality and final product accuracy. The relationship between segmentation quality and product accuracy is also briefly explored. Results suggest that input data transformations can aid in the delineation of landscape objects by image segmentation, but the effect is idiosyncratic to the transformation and object of interest. PMID:21673829

  18. Image tube. [deriving electron beam replica of image

    NASA Technical Reports Server (NTRS)

    Hallam, K. L.; Johnson, C. B. (Inventor)

    1974-01-01

    An optical image is projected onto a planar surface of a photocathode that derives an electron beam replica of the image. A target electrode displaced relative to the photocathode so that it does not obstruct the optical image includes a planar surface for receiving and deriving an accurate replica of the electron beam image. The two planar surfaces are parallel. The electron beam image is focused on the target electrode by providing throughout a region that extends between the planar surfaces of the photocathode and receiving electrode, constant homogeneous dc electric and magnetic fields. The electric field extends in a direction perpendicular to the planar surfaces while the magnetic field extends along a straight line that intersects the photocathode and target electrode at an acute angle.

  19. MRI-derived arterial input functions for PET kinetic modelling in rats

    NASA Astrophysics Data System (ADS)

    Evans, Eleanor; Sawiak, Stephen J.; Adrian Carpenter, T.

    2013-02-01

    Simultaneous PET-MR acquisition provides the high temporal and spatial resolution of MRI with the specificity of PET. In PET, accurate modelling of physiological function in vivo requires the time-activity curve of tracer in blood plasma, known as the arterial input function (AIF). As the gold standard method of blood sampling is inherently prohibitive in the small animal case, here we discuss how we prepare to rapidly sample MRI signals from gadolinium-doped tracer to obtain the tracer input functions from a simultaneous PET-MR measurement. ΔR2* measurements taken from EPI images were used to obtain first pass bolus AIFs in the rat brain from DSC-MRI datasets of 5 rats. AIFs obtained using our automatic algorithm were found to be consistent between animals and compared well with manual methods without need for a priori voxel selection. A variable flip angle FLASH sequence used for T1 mapping was successfully tested in a phantom study, providing accurate measurements of Gd concentration.

  20. 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.

  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. 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.

  3. 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.

  4. Forecasting future phosphorus export to the Laurentian Great Lakes from land-derived nutrient inputs

    NASA Astrophysics Data System (ADS)

    LaBeau, M. B.; Robertson, D. M.; Mayer, A. S.; Pijanowski, B. C.

    2011-12-01

    Anthropogenic use of the land through agricultural and urban activities has significantly increased phosphorus loading to rivers that flow to the Great Lakes. Phosphorus (P) is a critical element in the eutrophication of the freshwater ecosystems, most notably the Great Lakes. To better understand factors influencing phosphorus delivery to aquatic systems and thus their potential harmful effects to lake ecosystems, models that predict P export should incorporate account for changing changes in anthropogenic activities. Land-derived P from high yielding sources, such as agriculture and urban areas, affect eutrophication at various scales (e.g. specific bays to all of Lake Erie). SPARROW (SPAtially Referenced Regression On Watershed attributes) is a spatially explicit watershed model that has been used to understand linkages between land-derived sources and nutrient transport to the Great Lakes. The Great Lakes region is expected to experience a doubling of urbanized areas along with a ten percent increase in agricultural use over the next 40 years, which is likely to increase P loading. To determine how these changes will impact P loading, SPARROW have been developed that relate changes in land use to changes in nutrient sources, including relationships between row crop acreage and fertilizer intensity and urban land use and point source intensity. We used land use projections from the Land Transformation Model, a, spatially explicit, neural-net based land change model. Land use patterns from current to 2040 were used as input into HydroSPARROW, a forecasting tool that enables SPARROW to simulate the effects of various land-use and climate scenarios. Consequently, this work is focusing on understanding the effects of how specific agriculture and urbanization activities affect P loading in the watersheds of the Laurentian Great Lakes to potentially find strategies to reduce the extent and severity of future eutrophication.

  5. Ground Motion Simulations for Bursa Region (Turkey) Using Input Parameters derived from the Regional Seismic Network

    NASA Astrophysics Data System (ADS)

    Unal, B.; Askan, A.

    2014-12-01

    Earthquakes are among the most destructive natural disasters in Turkey and it is important to assess seismicity in different regions with the use of seismic networks. Bursa is located in Marmara Region, Northwestern Turkey and to the south of the very active North Anatolian Fault Zone. With around three million inhabitants and key industrial facilities of the country, Bursa is the fourth largest city in Turkey. Since most of the focus is on North Anatolian Fault zone, despite its significant seismicity, Bursa area has not been investigated extensively until recently. For reliable seismic hazard estimations and seismic design of structures, assessment of potential ground motions in this region is essential using both recorded and simulated data. In this study, we employ stochastic finite-fault simulation with dynamic corner frequency approach to model previous events as well to assess potential earthquakes in Bursa. To ensure simulations with reliable synthetic ground motion outputs, the input parameters must be carefully derived from regional data. In this study, using strong motion data collected at 33 stations in the region, site-specific parameters such as near-surface high frequency attenuation parameter and amplifications are obtained. Similarly, source and path parameters are adopted from previous studies that as well employ regional data. Initially, major previous events in the region are verified by comparing the records with the corresponding synthetics. Then simulations of scenario events in the region are performed. We present the results in terms of spatial distribution of peak ground motion parameters and time histories at selected locations.

  6. Image processing software for providing radiometric inputs to land surface climatology models

    NASA Technical Reports Server (NTRS)

    Newcomer, Jeffrey A.; Goetz, Scott J.; Strebel, Donald E.; Hall, Forrest G.

    1989-01-01

    During the First International Land Surface Climatology Project (ISLSCP) Field Experiment (FIFE), 80 gigabytes of image data were generated from a variety of satellite and airborne sensors in a multidisciplinary attempt to study energy and mass exchange between the land surface and the atmosphere. To make these data readily available to researchers with a range of image data handling experience and capabilities, unique image-processing software was designed to perform a variety of nonstandard image-processing manipulations and to derive a set of standard-format image products. The nonconventional features of the software include: (1) adding new layers of geographic coordinates, and solar and viewing conditions to existing data; (2) providing image polygon extraction and calibration of data to at-sensor radiances; and, (3) generating standard-format derived image products that can be easily incorporated into radiometric or climatology models. The derived image products consist of easily handled ASCII descriptor files, byte image data files, and additional per-pixel integer data files (e.g., geographic coordinates, and sun and viewing conditions). Details of the solutions to the image-processing problems, the conventions adopted for handling a variety of satellite and aircraft image data, and the applicability of the output products to quantitative modeling are presented. They should be of general interest to future experiment and data-handling design considerations.

  7. 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.

  8. 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

  9. Derivation of Auroral Conductances from IMAGE FUV

    NASA Astrophysics Data System (ADS)

    Immel, T. J.; Mende, S. B.; Frey, H. U.; Gerard, J.; Hubert, B.

    2001-05-01

    Auroral emissions are observed in 3 separate Far-Ultraviolet (FUV) wavelength regimes by IMAGE. The Wideband Imaging Camera (WIC) is sensitive mainly to N2 LBH and N I emissions in the 140-190-nm range, while the Spectrographic Imager (SI) spectrally separates the OI 135.6-nm emission and Doppler shifted hydrogen emissions of the proton aurora at 121.8 nm. The brightness of the N2 LBH and OI 135.6-nm emissions depend in part on the spectrum and total energy flux of incoming electrons, and on the height-density profile of the respective species, and O2. Due mainly to these atmospheric factors, the ratio of the N2 and OI emissions depends strongly on the characteristic energy of precipitating electrons which, once estimated, can in turn be used to calculate the total energy flux. The proton aurora generates secondary electrons, which excite additional emissions of N2 and OI. It is not possible to absolutely determine either the total proton energy flux or the characteristic proton energy () with a single proton imaging channel. However, the proton-induced N2 and OI emissions depend mainly on the total proton energy flux, so reasonable estimates of can be used in the calculation of proton energy input. Ground-based or in-situ observations of proton energies can help in this determination. With accurate corrections for N2 and OI airglow emissions, and formulae such as those provided by Robinson et al. [1987], IMAGE FUV can provide global maps of height-integrated conductivity (conductance) in the auroral oval. It is also possible to examine the degree to which the proton aurora contributes to enhanced conductance on a global scale. The promise of providing these conductances using IMAGE's real-time capabilities will be discussed. Robinson, R. M., R. R. Vondrak, K. Miller, T. Dabbs, and D. Hardy, On Calculating Ionospheric Conductances from the Flux and Energy of Precipitating Electrons, J. Geophys. Res., 92, 2566, 1987.

  10. Multimedia input in automated image annotation and content-based retrieval

    NASA Astrophysics Data System (ADS)

    Srihari, Rohini K.

    1995-03-01

    This research explores the interaction of linguistic and photographic information in an integrated text/image database. By utilizing linguistic descriptions of a picture (speech and text input) coordinated with pointing references to the picture, we extract information useful in two aspects: image interpretation and image retrieval. In the image interpretation phase, objects and regions mentioned in the text are identified; the annotated image is stored in a database for future use. We incorporate techniques from our previous research on photo understanding using accompanying text: a system, PICTION, which identifies human faces in a newspaper photograph based on the caption. In the image retrieval phase, images matching natural language queries are presented to a user in a ranked order. This phase combines the output of (1) the image interpretation/annotation phase, (2) statistical text retrieval methods, and (3) image retrieval methods (e.g., color indexing). The system allows both point and click querying on a given image as well as intelligent querying across the entire text/image database.

  11. 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. )

    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.

  12. Global Auroral Energy Deposition Derived from Polar UVI Images

    NASA Technical Reports Server (NTRS)

    Fillingim, M. O.; Brittnacher, M. J.; Elsen, R.; Parks, G. K.; Spann, J. F., Jr.; Germany, G. A.

    1997-01-01

    Quantitative measurement of the transfer of energy and momentum to the ionosphere from the solar wind is one of the main objectives of the ISTP program. Global measurement of auroral energy deposition derived from observations of the longer wavelength LBH band emissions made by the Ultraviolet Imager on the Polar spacecraft is one of the key elements in this satellite and ground-based instrument campaign. These "measurements" are inferred by combining information from consecutive images using different filters and have a time resolution on the average of three minutes and are made continuously over a 5 to 8 hour period during each 18 hour orbit of the Polar spacecraft. The energy deposition in the ionosphere from auroral electron precipitation augments are due to Joule heating associated with field aligned currents. Assuming conjugacy of energy deposition between the two hemispheres the total energy input to the ionosphere through electron precipitation can be determined at high time resolution. Previously, precipitating particle measurements along the tracks of low altitude satellites provided only local measurements and the global energy precipitation could be inferred through models but not directly measured. We use the UVI images for the entire month of January 1997 to estimate the global energy deposition at high time resolution. We also sort the energy deposition into sectors to find possible trends, for example, on the dayside and nightside, or the dawn and dusk sides.

  13. Multiple-input multiple-output 3D imaging laser radar

    NASA Astrophysics Data System (ADS)

    Liu, Chunbo; Wu, Chao; Han, Xiang'e.

    2015-10-01

    A 3D (angle-angle-range) imaging laser radar (LADAR) based on multiple-input multiple-output structure is proposed. In the LADAR, multiple coherent beams are randomly phased to form the structured light field and an APD array detector is utilized to receive the echoes from target. The sampled signals from each element of APD are correlated with the referenced light to reconstruct the local 3D images of target. The 3D panorama of target can be obtained by stitching the local images of all the elements. The system composition is described first, then the operation principle is presented and numerical simulations are provided to show the validity of the proposed scheme.

  14. Glutamate Synaptic Inputs to Ventral Tegmental Area Neurons in the Rat Derive Primarily from Subcortical Sources

    PubMed Central

    Omelchenko, Natalia; Sesack, Susan R.

    2007-01-01

    Dopamine and GABA neurons in the ventral tegmental area project to the nucleus accumbens and prefrontal cortex and modulate locomotor and reward behaviors as well as cognitive and affective processes. Both midbrain cell types receive synapses from glutamate afferents that provide an essential control of behaviorally-linked activity patterns, although the sources of glutamate inputs have not yet been completely characterized. We used antibodies against the vesicular glutamate transporters VGlut1 and VGlut2 to investigate the morphology and synaptic organization of axons containing these proteins as putative markers of glutamate afferents from cortical versus subcortical sites, respectively. We also characterized the ventral tegmental area cell populations receiving VGlut1+ or VGlut2+ synapses according to their transmitter phenotype (dopamine or GABA) and major projection target (nucleus accumbens or prefrontal cortex). By light and electron microscopic examination, VGlut2+ as opposed to VGlut1+ axon terminals were more numerous, had a larger average size, synapsed more proximally, and were more likely to form convergent synapses onto the same target. Both axon types formed predominantly asymmetric synapses, although VGlut2+ terminals more often formed synapses with symmetric morphology. No absolute selectivity was observed for VGlut1+ or VGlut2+ axons to target any particular cell population. However, the synapses onto mesoaccumbens neurons more often involved VGlut2+ terminals, whereas mesoprefrontal neurons received relatively equal synaptic inputs from VGlut1+ and VGlut2+ profiles. The distinct morphological features of VGlut1 and VGlut2 positive axons suggest that glutamate inputs from presumed cortical and subcortical sources, respectively, differ in the nature and intensity of their physiological actions on midbrain neurons. More specifically, our findings imply that subcortical glutamate inputs to the ventral tegmental area expressing VGlut2 predominate over cortical sources of excitation expressing VGlut1 and are more likely to drive the behaviorally-linked bursts in dopamine cells that signal future expectancy or attentional shifting. PMID:17391856

  15. Improved factor analysis of dynamic PET images to estimate arterial input function and tissue curves

    NASA Astrophysics Data System (ADS)

    Boutchko, Rostyslav; Mitra, Debasis; Pan, Hui; Jagust, William; Gullberg, Grant T.

    2015-03-01

    Factor analysis of dynamic structures (FADS) is a methodology of extracting time-activity curves (TACs) for corresponding different tissue types from noisy dynamic images. The challenges of FADS include long computation time and sensitivity to the initial guess, resulting in convergence to local minima far from the true solution. We propose a method of accelerating and stabilizing FADS application to sequences of dynamic PET images by adding preliminary cluster analysis of the time activity curves for individual voxels. We treat the temporal variation of individual voxel concentrations as a set of time-series and use a partial clustering analysis to identify the types of voxel TACs that are most functionally distinct from each other. These TACs provide a good initial guess for the temporal factors for subsequent FADS processing. Applying this approach to a set of single slices of dynamic 11C-PIB images of the brain allows identification of the arterial input function and two different tissue TACs that are likely to correspond to the specific and non-specific tracer binding-tissue types. These results enable us to perform direct classification of tissues based on their pharmacokinetic properties in dynamic PET without relying on a compartment-based kinetic model, without identification of the reference region, or without using any external methods of estimating the arterial input function, as needed in some techniques.

  16. 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

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

    NASA Astrophysics Data System (ADS)

    Ikeda, Kanami; Watanabe, Eriko

    2015-02-01

    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.

  18. Estimation of Enterococci Input from Bathers and Animals on A Recreational Beach Using Camera Images

    PubMed Central

    D, Wang John; M, Solo-Gabriele Helena; M, Abdelzaher Amir; E, Fleming Lora

    2010-01-01

    Enterococci, are used nationwide as a water quality indicator of marine recreational beaches. Prior research has demonstrated that enterococci inputs to the study beach site (located in Miami, FL) are dominated by non-point sources (including humans and animals). We have estimated their respective source functions by developing a counting methodology for individuals to better understand their non-point source load impacts. The method utilizes camera images of the beach taken at regular time intervals to determine the number of people and animal visitors. The developed method translates raw image counts for weekdays and weekend days into daily and monthly visitation rates. Enterococci source functions were computed from the observed number of unique individuals for average days of each month of the year, and from average load contributions for humans and for animals. Results indicate that dogs represent the larger source of enterococci relative to humans and birds. PMID:20381094

  19. Design method of input phase mask to improve light use efficiency and reconstructed image quality for holographic memory.

    PubMed

    Saita, Yusuke; Nomura, Takanori

    2014-07-01

    A design method of an input phase mask for holographic memory is proposed. In the method, a modification of a design procedure and another restraint condition are applied to our conventional design method. The light use efficiency and the quality of a reconstructed image are improved. The performance of an input phase mask designed by the method is confirmed by numerical simulations. Finally, a suitable design condition of an input phase mask is determined from simulation results. PMID:25089971

  20. Spatially multiplexed multi-input-multi-output optical imaging system in a turbid, turbulent atmosphere.

    PubMed

    Hajjarian, Zeinab; Kavehrad, Mohsen; Fadlullah, Jarir

    2010-03-20

    Active optical imaging is preferred over radio frequency counterparts due to its higher resolution, faster area search rate, and relatively easier learning and interpretation of the image by a human observer. However, in imaging through atmosphere, one should consider dispersive effects of multiple scatterings and turbulence-induced wave perturbations, which give rise to intensity fluctuations and wavefront distortions. All these phenomena broaden and distort the spatial impulse response known as the point spread function (PSF). In this paper, a spatially multiplexed multi-input-multi-output imaging system design, inspired by multispot diffuse indoor communications configuration first introduced by Yun and Kavehrad [IEEE International Conference Selected Topics in Wireless Communications (IEEE, 1992), pp 262-265], is presented. At the transmitter, a computer-generated holographic beam splitter is used to generate arrays of beamlets, providing a faster area search rate and a uniformly distributed illumination over the entire target area. Then, at the receiver, an array of photodetectors is used to collect the reflected rays. While a Monte Carlo ray-tracing algorithm developed at Pennsylvania State University, Center for Information and Communications Research (CICTR), is used to model imaging in multiple-scattering turbid media, phase screens are employed to simulate turbulence-induced wavefront distortions. Hence, a comprehensive framework is exploited that takes into account possible sources of degradation. Using this framework, system performance is analyzed under different meteorological conditions. Restoration techniques such as adaptive-optics corrections, blind deconvolution, and time gating are used to improve the contrast and enhance the sharpness and resolution of the images. PMID:20300147

  1. Cattle-derived microbial input to source water catchments: An experimental assessment of stream crossing modification.

    PubMed

    Smolders, Andrew; Rolls, Robert J; Ryder, Darren; Watkinson, Andrew; Mackenzie, Mark

    2015-06-01

    The provision of safe drinking water is a global issue, and animal production is recognized as a significant potential origin of human infectious pathogenic microorganisms within source water catchments. On-farm management can be used to mitigate livestock-derived microbial pollution in source water catchments to reduce the risk of contamination to potable water supplies. We applied a modified Before-After Control Impact (BACI) design to test if restricting the access of livestock to direct contact with streams prevented longitudinal increases in the concentrations of faecal indicator bacteria and suspended solids. Significant longitudinal increases in pollutant concentrations were detected between upstream and downstream reaches of the control crossing, whereas such increases were not detected at the treatment crossing. Therefore, while the crossing upgrade was effective in preventing cattle-derived point source pollution by between 112 and 158%, diffuse source pollution to water supplies from livestock is not ameliorated by this intervention alone. Our findings indicate that stream crossings that prevent direct contact between livestock and waterways provide a simple method for reducing pollutant loads in source water catchments, which ultimately minimises the likelihood of pathogenic microorganisms passing through source water catchments and the drinking water supply system. The efficacy of the catchment as a primary barrier to pathogenic risks to drinking water supplies would be improved with the integration of management interventions that minimise direct contact between livestock and waterways, combined with the mitigation of diffuse sources of livestock-derived faecal matter from farmland runoff to the aquatic environment. PMID:25841195

  2. Groundwater-derived nutrient inputs to the Upper Gulf of Thailand

    NASA Astrophysics Data System (ADS)

    Burnett, William C.; Wattayakorn, Gullaya; Taniguchi, Makoto; Dulaiova, Henrieta; Sojisuporn, Pramot; Rungsupa, Sompop; Ishitobi, Tomotoshi

    2007-01-01

    We report here the first direct measurements of nutrient fluxes via groundwater discharge into the Upper Gulf of Thailand. Nutrient and standard oceanographic surveys were conducted during the wet and dry seasons along the Chao Phraya River, Estuary and out into the Upper Gulf of Thailand. Additional measurements in selected near-shore regions of the Gulf included manual and automatic seepage meter deployments, as well as nutrient evaluations of seepage and coastal waters. The river transects characterized the distribution of biogeochemical parameters in this highly contaminated urban environment. Seepage flux measurements together with nutrient analyses of seepage fluids were used to estimate nutrient fluxes via groundwater pathways for comparison to riverine fluxes. Our findings show that disseminated seepage of nutrient-rich mostly saline groundwater into the Upper Gulf of Thailand is significant. Estimated fluxes of dissolved inorganic nitrogen (DIN) supplied via groundwater discharge were 40-50% of that delivered by the Chao Phraya River, inorganic phosphate was 60-70%, and silica was 15-40%. Dissolved organic nitrogen (DON) and phosphorus (DOP) groundwater fluxes were also high at 30-40% and 30-130% of the river inputs, respectively. These observations are especially impressive since the comparison is being made to the river that is the largest source of fresh water into the Gulf of Thailand and flows directly through the megacity of Bangkok with high nutrient loadings from industrial and domestic sources.

  3. Derivation of input function from FDG-PET studies in small hearts

    SciTech Connect

    Wu, Hsiao-Ming; Huang, Sung-Cheng; Allada, V.

    1996-10-01

    The extraction of pure arterial time-activity curves (TACs) from dynamic PET images of a small animal heart using factor analysis of dynamic structures (FADS) was found to be unsuccessful due to the small size of the cardiac chamber that causes extensive mixture of TACs of different structures. In this study, we used digital phantoms of the left ventricle (LV cavity size: 1-2 cm) and small monkey (LV cavity size: {approx} 2 cm) dynamic FDG PET studies to evaluate FADS for extracting the pure blood-pool TACs by adding a single blood sample (taken at a late scan time) constraint. In the digital phantom studies, spillover fractions in the extracted blood-pool TACs using FADS without a blood sample constraint (FADS(-)) and with a blood sample constraint (FADS(+)) were 3%-91% and < 3%, respectively. In the monkey studies (n = 4), FADS(+) extracted blood-pool TACs matched well with the arterialized well counter measurements (% differences of curve integration: FADS(-) < 82%; FADS(+) < 9%). The microparameters (K*{sub 1}, k*{sub 2}, k*{sub 3}, k*{sub 4}) and macroparameters (K{sub nlr}), obtained from the FADS(+) blood-pool TACs, were similar to those obtained from plasma samples in a three-compartment model fitting (% differences of K{sub nlr}: phantom studies < 5%; monkey studies < 9%). The FADS technique with a single-blood sample has the potential to extract the pure blood-pool TACs directly from dynamic PET images of a small animal without multiple blood sampling, region of interest definition or spillover correction. 14 refs., 5 figs., 3 tabs.

  4. Combustion-derived substances in deep basins of Puget Sound: historical inputs from fossil fuel and biomass combustion.

    PubMed

    Kuo, Li-Jung; Louchouarn, Patrick; Herbert, Bruce E; Brandenberger, Jill M; Wade, Terry L; Crecelius, Eric

    2011-04-01

    Reconstructions of 250 years historical inputs of two distinct types of black carbon (soot/graphitic black carbon (GBC) and char-BC) were conducted on sediment cores from two basins of the Puget Sound, WA. Signatures of polycyclic aromatic hydrocarbons (PAHs) were also used to support the historical reconstructions of BC to this system. Down-core maxima in GBC and combustion-derived PAHs occurred in the 1940s in the cores from the Puget Sound Main Basin, whereas in Hood Canal such peak was observed in the 1970s, showing basin-specific differences in inputs of combustion byproducts. This system showed relatively higher inputs from softwood combustion than the northeastern U.S. The historical variations in char-BC concentrations were consistent with shifts in climate indices, suggesting an influence of climate oscillations on wildfire events. Environmental loading of combustion byproducts thus appears as a complex function of urbanization, fuel usage, combustion technology, environmental policies, and climate conditions. PMID:21236534

  5. Multi-modal pharmacokinetic modelling for DCE-MRI: using diffusion weighted imaging to constrain the local arterial input function

    NASA Astrophysics Data System (ADS)

    Hamy, Valentin; Modat, Marc; Shipley, Rebecca; Dikaios, Nikos; Cleary, Jon; Punwani, Shonit; Ourselin, Sebastien; Atkinson, David; Melbourne, Andrew

    2014-03-01

    The routine acquisition of multi-modal magnetic resonance imaging data in oncology yields the possibility of combined model fitting of traditionally separate models of tissue structure and function. In this work we hypothesise that diffusion weighted imaging data may help constrain the fitting of pharmacokinetic models to dynamic contrast enhanced (DCE) MRI data. Parameters related to tissue perfusion in the intra-voxel incoherent motion (IVIM) modelling of diffusion weighted MRI provide local information on how tissue is likely to perfuse that can be utilised to guide DCE modelling via local modification of the arterial input function (AIF). In this study we investigate, based on multi-parametric head and neck MRI of 8 subjects (4 with head and neck tumours), the benefit of incorporating parameters derived from the IVIM model within the DCE modelling procedure. Although we find the benefit of this procedure to be marginal on the data used in this work, it is conceivable that a technique of this type will be of greater use in a different application.

  6. Determination of electron and proton auroral energy inputs from FUV-IMAGE

    NASA Astrophysics Data System (ADS)

    Grard, J.; Hubert, B.; Meurant, M.; Frey, H. U.; Mende, S. B.; Immel, T.; Bisikalo, D. V.; Shematovich, V. I.; Gladstone, G. R.

    2001-05-01

    The FUV experiment onboard the IMAGE spacecraft offers the unique possibility to obtain simultaneous snapshots of the global north aurora every 2 minutes in three different spectral channels. The WIC camera has a broadband channel covering the 135-190 nm interval including the N2 LBH bands, part of which may be absorbed by O2. The SI13 channel is centered on the OI 135.6 nm line which is optically thin and includes a ~ 40% LBH contribution. Finally, the SI12 camera images the Doppler-shifted Ly-? emission excited by the proton aurora. This set of instrumentation is combined with auroral models to determine the electron and the proton energy fluxes from the magnetosphere. Examples will be presented and compared with the values deduced from the NOAA satellites. Simultaneous in-situ measurements of the particle characteristic energy have been combined with the data extracted from the FUV images to validate the models and derive empirical relationships between the particle flux measured by the detectors and the brightness observed by FUV-IMAGE at the footprint of the same magnetic field line. Finally, we will assess the ability to deduce the characteristic energy of the auroral particles from the ratio of co-registered images in the WIC and SI13 cameras. This method is based on the difference of vertical distribution of the LBH and the OI 135.6 nm emissions. It offers the potential to globally remotely sense not only the energy flux from the magnetosphere but also the main features of the electron characteristic energy.

  7. 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

  8. 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.

  9. Landsat Thematic Mapper image-derived MTF

    NASA Technical Reports Server (NTRS)

    Schowengerdt, R. A.; Archwamety, C.; Wrigley, R. C.

    1985-01-01

    The Landsat Image Data Quality Analysis (LIDQA) Program conducted by NASA has the objective to quantify the performance of the Thematic Mapper (TM) on the Landsat-4 and Landsat-5 spacecraft. The interest in the spatial resolution performance of the TM is partly related to the decrease of the instantaneous field of view (IFOV) from 80 m for the MSS to 30 m for the TM. Studies related to the preflight line spread function (LSF), square wave response (SWR), and theoretical component modeling of the TM system modulation transfer function (MTF) have been conducted. However, the need remains to estimate the MTF of the complete system. The present paper is concerned with investigations related to this task. Attention is given to three approaches for measuring the MTF of the TM system from imagery.

  10. Dual-input two-compartment pharmacokinetic model of dynamic contrast-enhanced magnetic resonance imaging in hepatocellular carcinoma

    PubMed Central

    Yang, Jian-Feng; Zhao, Zhen-Hua; Zhang, Yu; Zhao, Li; Yang, Li-Ming; Zhang, Min-Ming; Wang, Bo-Yin; Wang, Ting; Lu, Bao-Chun

    2016-01-01

    AIM: To investigate the feasibility of a dual-input two-compartment tracer kinetic model for evaluating tumorous microvascular properties in advanced hepatocellular carcinoma (HCC). METHODS: From January 2014 to April 2015, we prospectively measured and analyzed pharmacokinetic parameters [transfer constant (Ktrans), plasma flow (Fp), permeability surface area product (PS), efflux rate constant (kep), extravascular extracellular space volume ratio (ve), blood plasma volume ratio (vp), and hepatic perfusion index (HPI)] using dual-input two-compartment tracer kinetic models [a dual-input extended Tofts model and a dual-input 2-compartment exchange model (2CXM)] in 28 consecutive HCC patients. A well-known consensus that HCC is a hypervascular tumor supplied by the hepatic artery and the portal vein was used as a reference standard. A paired Student’s t-test and a nonparametric paired Wilcoxon rank sum test were used to compare the equivalent pharmacokinetic parameters derived from the two models, and Pearson correlation analysis was also applied to observe the correlations among all equivalent parameters. The tumor size and pharmacokinetic parameters were tested by Pearson correlation analysis, while correlations among stage, tumor size and all pharmacokinetic parameters were assessed by Spearman correlation analysis. RESULTS: The Fp value was greater than the PS value (FP = 1.07 mL/mL per minute, PS = 0.19 mL/mL per minute) in the dual-input 2CXM; HPI was 0.66 and 0.63 in the dual-input extended Tofts model and the dual-input 2CXM, respectively. There were no significant differences in the kep, vp, or HPI between the dual-input extended Tofts model and the dual-input 2CXM (P = 0.524, 0.569, and 0.622, respectively). All equivalent pharmacokinetic parameters, except for ve, were correlated in the two dual-input two-compartment pharmacokinetic models; both Fp and PS in the dual-input 2CXM were correlated with Ktrans derived from the dual-input extended Tofts model (P = 0.002, r = 0.566; P = 0.002, r = 0.570); kep, vp, and HPI between the two kinetic models were positively correlated (P = 0.001, r = 0.594; P = 0.0001, r = 0.686; P = 0.04, r = 0.391, respectively). In the dual input extended Tofts model, ve was significantly less than that in the dual input 2CXM (P = 0.004), and no significant correlation was seen between the two tracer kinetic models (P = 0.156, r = 0.276). Neither tumor size nor tumor stage was significantly correlated with any of the pharmacokinetic parameters obtained from the two models (P > 0.05). CONCLUSION: A dual-input two-compartment pharmacokinetic model (a dual-input extended Tofts model and a dual-input 2CXM) can be used in assessing the microvascular physiopathological properties before the treatment of advanced HCC. The dual-input extended Tofts model may be more stable in measuring the ve; however, the dual-input 2CXM may be more detailed and accurate in measuring microvascular permeability. PMID:27053857

  11. Automated reference region extraction and population-based input function for brain [11C]TMSX PET image analyses

    PubMed Central

    Rissanen, Eero; Tuisku, Jouni; Luoto, Pauliina; Arponen, Eveliina; Johansson, Jarkko; Oikonen, Vesa; Parkkola, Riitta; Airas, Laura; Rinne, Juha O

    2015-01-01

    [11C]TMSX ([7-N-methyl-11C]-(E)-8-(3,4,5-trimethoxystyryl)-1,3,7-trimethylxanthine) is a selective adenosine A2A receptor (A2AR) radioligand. In the central nervous system (CNS), A2AR are linked to dopamine D2 receptor function in striatum, but they are also important modulators of inflammation. The golden standard for kinetic modeling of brain [11C]TMSX positron emission tomography (PET) is to obtain arterial input function via arterial blood sampling. However, this method is laborious, prone to errors and unpleasant for study subjects. The aim of this work was to evaluate alternative input function acquisition methods for brain [11C]TMSX PET imaging. First, a noninvasive, automated method for the extraction of gray matter reference region using supervised clustering (SCgm) was developed. Second, a method for obtaining a population-based arterial input function (PBIF) was implemented. These methods were created using data from 28 study subjects (7 healthy controls, 12 multiple sclerosis patients, and 9 patients with Parkinson's disease). The results with PBIF correlated well with original plasma input, and the SCgm yielded similar results compared with cerebellum as a reference region. The clustering method for extracting reference region and the population-based approach for acquiring input for dynamic [11C]TMSX brain PET image analyses appear to be feasible and robust methods, that can be applied in patients with CNS pathology. PMID:25370856

  12. Data-derived spatiotemporal resolution constraints for global auroral imagers

    NASA Astrophysics Data System (ADS)

    Uritsky, Vadim M.; Donovan, Eric; Trondsen, Trond; Pineau, Deanna; Kozelov, Boris V.

    2010-09-01

    We present new data-derived constraints on spatiotemporal resolution of global auroral imagers. The reported results are based on an extensive set of images from two previously flown instruments, POLAR UVI and IMAGE WIC, processed using the event detection methodology developed by Uritsky et al. (2002, 2003, 2006). We use the cross-scale analysis of ground-based and spacecraft observations of auroral emission regions by Kozelov et al. (2004) to derive the power law exponent relating spatial and temporal scales of auroral precipitation events, and estimate the normalization factor entering this relation using the satellite data. Our results show the existence of a nontrivial scaling relation between the relaxation time and the spatial dimension of auroral emission events. We use this relation as a proxi to the resolution scaling function providing non-redundant combinations of spatial and temporal resolution of an optimized auroral imager consistent with the dynamics of multiscale auroral precipitation.

  13. 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

  14. Modular toolbox for derivative-based medical image registration

    NASA Astrophysics Data System (ADS)

    Franz, Astrid; Carlsen, Ingwer C.; Kabus, Sven; Netsch, Thomas; Pekar, Vladimir

    2005-04-01

    Registration of medical images, i.e. the integration of two or more images into a common geometrical system of reference so that corresponding image structures correctly align, is an active field of current research. Registration algorithms in general are composed of three main building blocks: a geometrical transformation is applied in order to transform the images into the geometrical system of reference, a similarity measure puts the comparison of the images into quantifiable terms, and an optimization algorithm searches for that transformation that leads to optimal similarity between the images. Whereas in the literature fixed configurations of registration algorithms are investigated, here we present a modular toolbox containing several similarity measures, transformation classes and optimization strategies. Derivative-free optimization is applicable for any similarity measure, but is not fast enough in clinical practice. Hence we consider much faster derivative-based Gauss-Newton and Levenberg-Marquardt optimization algorithms that can be used in conjunction with frequently needed similarity measures for which derivatives can be easily obtained. The implemented similarity measures, geometrical transformations and optimization methods can be freely combined in order to configure a registration algorithm matching the requirements of a particular clinical application. Test examples show that particular algorithm configurations out of this toolbox allow e.g. for an improved lesion identification and localization in PET-CT or MR registration applications.

  15. Priming in permafrost soils: High vulnerability of arctic soil organic carbon to increased input of plant-derived compounds

    NASA Astrophysics Data System (ADS)

    Wild, Birgit; Gentsch, Norman; Capek, Petr; Diakova, Katerina; Alves, Ricardo; Barta, Jiri; Gittel, Antje; Guggenberger, Georg; Lashchinskiy, Nikolay; Knoltsch, Anna; Mikutta, Robert; Santruckova, Hana; Schnecker, Jörg; Shibistova, Olga; Takriti, Mounir; Urich, Tim; Watzka, Margarete; Richter, Andreas

    2015-04-01

    Arctic ecosystems are warming rapidly, resulting in a stimulation of both plant primary production and soil organic matter (SOM) decomposition. In addition to this direct stimulation, SOM decomposition might also be indirectly affected by rising temperatures mediated by the increase in plant productivity. Higher root litter production for instance might decrease SOM decomposition by providing soil microorganisms with alternative C and N sources ("negative priming"), or might increase SOM decomposition by facilitating microbial growth and enzyme production ("positive priming"). With about 1,700 Pg of organic C stored in arctic soils, and 88% of that in horizons deeper than 30 cm, it is crucial to understand the controls on SOM decomposition in different horizons of arctic permafrost soils, and thus the vulnerability of SOM to changes in C and N availability in a future climate. We here report on the vulnerability of SOM in arctic permafrost soils to an increased input of plant-derived organic compounds, and on its variability across soil horizons and sites. We simulated an increased input of plant-derived compounds by amending soil samples with 13C-labelled cellulose or protein, and compared the mineralization of native, unlabelled soil organic C (SOC) to unamended control samples. Our experiment included 119 individual samples of arctic permafrost soils, covering four sites across the Siberian Arctic, and five soil horizons, i.e., organic topsoil, mineral topsoil, mineral subsoil and cryoturbated material (topsoil material buried in the subsoil by freeze-thaw processes) from the active layer, as well as thawed material from the upper permafrost. Our findings suggest that changes in C and N availability in Arctic soils, such as mediated by plants, have a high potential to alter the decomposition of SOM, but also point at fundamental differences between soil horizons. In the organic topsoil, SOC mineralization increased by 51% after addition of protein, but was not affected by cellulose, suggesting predominant N limitation of the microbial decomposer community, and a high vulnerability of SOM to increases in N availability. In contrast, in mineral subsoil and thawed permafrost, SOC mineralization was stimulated by both cellulose and protein (between 23 and 120%), cellulose- and protein-derived C was efficiently incorporated into the microbial biomass, and effects of both cellulose and protein were significantly correlated. These findings suggest predominant C limitation of the microbial decomposer community in deeper, mineral horizons of arctic permafrost soils, and point at a high vulnerability of SOM to increased C availability, e.g., due to higher root litter production. We estimate that on a circum-arctic scale, increases in C and N availability have the potential to stimulate SOC mineralization in the order of several Tg C per day. Together with the direct stimulation of SOC mineralization by rising temperatures, this indirect stimulation can counteract the increased CO2 fixation by plants, and thus reduce the C sink strength of arctic ecosystems or even provoke net ecosystem C losses that might induce a positive feedback to global warming.

  16. Inner Magnetospheric Electric Fields Derived from IMAGE EUV

    NASA Technical Reports Server (NTRS)

    Gallagher, D. L.; Adrian, M. L.

    2007-01-01

    The local and global patterns of plasmaspheric plasma transport reflect the influence of electric fields imposed by all sources in the inner magnetosphere. Image sequences of thermal plasma G:istribution obtained from the IMAGE Mission Extreme Ultraviolet Imager can be used to derive plasma motions and, using a magnetic field model, the corresponding electric fields. These motions and fields directly reflect the dynamic coupling of injected plasmasheet plasma and the ionosphere, in addition to solar wind and atmospheric drivers. What is being learned about the morphology of inner magnetospheric electric fields during storm and quite conditions from this new empirical tool will be presented and discussed.

  17. 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

  18. Antibody-Derived In Vivo Imaging of Tau Pathology

    PubMed Central

    Krishnaswamy, Senthilkumar; Lin, Yan; Rajamohamedsait, Wajitha J.; Rajamohamedsait, Hameetha B.; Krishnamurthy, Pavan

    2014-01-01

    Antibodies or their derivatives as imaging probes for pathological tau protein have great potential, but have not been well studied. In particular, smaller, single-chain-variable antibody fragments (scFv's) are attractive for detecting tau lesions in live subjects. Here, we generated libraries of scFv's and identified numerous phospho-tau-selective scFv's. Peripheral injection of one of these scFv's consistently resulted in a strong in vivo brain signal in transgenic tauopathy mice, but not in wild-type or amyloid-β plaque mice. The parent tau antibody provided similar results, albeit with a weaker signal intensity. The imaging signal correlated very well with colocalization of the probe with intraneuronal tau aggregates. Both were associated with markers of endosomes, autophagosomes, and lysosomes, suggesting their interaction in these degradation pathways. Such specific antibody-derived imaging probes have great potential as diagnostic markers for Alzheimer's disease and related tauopathies. PMID:25505335

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

    NASA Astrophysics Data System (ADS)

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

    2011-03-01

    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 2003 along two major sediment transport pathways south and west of the Mississippi River mouth. Lignin profiles in these age-dated cores (210Pb geochronology) indicate artificial reservoir retention as a primary control on organic carbon quantity and quality reaching the margin post-1950, whereas pre-1950 sediments may reflect soil erosion due to land clearing and farming practices. Lignin (?8) concentrations (range 0.2 to 1.7) also indicate that TOCT delivery rates/decay processes have probably remained relatively consistent from proximal to distal stations along transects. The down-core profile at the Canyon station seems to be temporally linked and connected to inner shelf deposition, suggestive of rapid cross-shelf transport. Sources of terrestrially derived organic carbon were reflective of mixed angiosperms over the last 150 years in cores west and south of the Mississippi River delta. The lignin-phenol vegetation index (LPVI) (range 130.0 to 510) proved to be a sensitive indicator of source changes in these sediments and eliminated some of the variability compared to C/V (range 0.01 to 0.4) and S/V (range 0.9 to 2.1) ratios. Stochastic events such as hurricanes and large river floods have a measurable, albeit ephemeral, effect on the shelf TOCT record. Burial of TOCT on the river-dominated Louisiana continental margin is largely driven by anthropogenic land-use alterations in the last 150 years. Land-use changes in the Mississippi River basin and river damming have likely affected carbon cycling and TOCT burial on the Louisiana continental margin over a large spatial extent as observed by similar trends in cores from across and along the margin.

  20. 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 μm2 and 256 gray levels was used. To image synthesized encryption kinoforms phase LC SLM HoloEye PLUTO VIS with 1920×1080 pixels 8×8 μm2 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.

  1. 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

    Prvost, 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

  2. 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…

  3. Intensity Inhomogeneity Correction of Structural MR Images: A Data-Driven Approach to Define Input Algorithm Parameters

    PubMed Central

    Ganzetti, Marco; Wenderoth, Nicole; Mantini, Dante

    2016-01-01

    Intensity non-uniformity (INU) in magnetic resonance (MR) imaging is a major issue when conducting analyses of brain structural properties. An inaccurate INU correction may result in qualitative and quantitative misinterpretations. Several INU correction methods exist, whose performance largely depend on the specific parameter settings that need to be chosen by the user. Here we addressed the question of how to select the best input parameters for a specific INU correction algorithm. Our investigation was based on the INU correction algorithm implemented in SPM, but this can be in principle extended to any other algorithm requiring the selection of input parameters. We conducted a comprehensive comparison of indirect metrics for the assessment of INU correction performance, namely the coefficient of variation of white matter (CVWM), the coefficient of variation of gray matter (CVGM), and the coefficient of joint variation between white matter and gray matter (CJV). Using simulated MR data, we observed the CJV to be more accurate than CVWM and CVGM, provided that the noise level in the INU-corrected image was controlled by means of spatial smoothing. Based on the CJV, we developed a data-driven approach for selecting INU correction parameters, which could effectively work on actual MR images. To this end, we implemented an enhanced procedure for the definition of white and gray matter masks, based on which the CJV was calculated. Our approach was validated using actual T1-weighted images collected with 1.5 T, 3 T, and 7 T MR scanners. We found that our procedure can reliably assist the selection of valid INU correction algorithm parameters, thereby contributing to an enhanced inhomogeneity correction in MR images. PMID:27014050

  4. Robust image region descriptor using local derivative ordinal binary pattern

    NASA Astrophysics Data System (ADS)

    Shang, Jun; Chen, Chuanbo; Pei, Xiaobing; Liang, Hu; Tang, He; Sarem, Mudar

    2015-05-01

    Binary image descriptors have received a lot of attention in recent years, since they provide numerous advantages, such as low memory footprint and efficient matching strategy. However, they utilize intermediate representations and are generally less discriminative than floating-point descriptors. We propose an image region descriptor, namely local derivative ordinal binary pattern, for object recognition and image categorization. In order to preserve more local contrast and edge information, we quantize the intensity differences between the central pixels and their neighbors of the detected local affine covariant regions in an adaptive way. These differences are then sorted and mapped into binary codes and histogrammed with a weight of the sum of the absolute value of the differences. Furthermore, the gray level of the central pixel is quantized to further improve the discriminative ability. Finally, we combine them to form a joint histogram to represent the features of the image. We observe that our descriptor preserves more local brightness and edge information than traditional binary descriptors. Also, our descriptor is robust to rotation, illumination variations, and other geometric transformations. We conduct extensive experiments on the standard ETHZ and Kentucky datasets for object recognition and PASCAL for image classification. The experimental results show that our descriptor outperforms existing state-of-the-art methods.

  5. Genetic dissection of retinal inputs to brainstem nuclei controlling image stabilization.

    PubMed

    Dhande, Onkar S; Estevez, Maureen E; Quattrochi, Lauren E; El-Danaf, Rana N; Nguyen, Phong L; Berson, David M; Huberman, Andrew D

    2013-11-01

    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

  6. 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

  7. Neutral hydrogen density profiles derived from geocoronal imaging

    NASA Astrophysics Data System (ADS)

    Ostgaard, N.; Mende, S. B.; Frey, H. U.; Gladstone, R.

    2002-05-01

    The geocorona is produced when solar Lyman α radiation is resonance scattered by neutral hydrogen in the exosphere. Measurements of the geocoronal brightness from space can therefore be used to derive the density profile of neutral hydrogen sorrounding the Earth. The Geocorononal Imager (GEO) which is part of the FUV imaging system onboard the IMAGE satellite, is designed to measure the geocoronal Lyman α emissions. In this paper we present radial density profiles of the neutral hydrogen in the magnetosphere derived from the GEO data of Lyman α column brightness. The variable solar Lyman α flux is obtained from the UARS/SOLSTICE measurements and the scattered solar Lyman α emissions from interplanetary hydrogen is obtained from a model. At high altitudes (>3RE) we assume that the exosphere can be considered as an optical thin medium. Assuming that the hydrogen density profile can be expressed as a double exponential it is shown that the Lyman α column brightness can be converted to hydrogen density profiles in each local time sector. Our results show the same shape but indicate higher hydrogen density >5RE than has been reported earlier. Our results are valid >3RE.

  8. Single input state, single-mode fiber-based polarization-sensitive optical frequency domain imaging by eigenpolarization referencing.

    PubMed

    Lippok, Norman; Villiger, Martin; Jun, Changsu; Bouma, Brett E

    2015-05-01

    Fiber-based polarization-sensitive optical frequency domain imaging is more challenging than free-space implementations. Using multiple input states, fiber-based systems provide sample birefringence information with the benefit of a flexible sample arm but come at the cost of increased system and acquisition complexity, and either reduce acquisition speed or require increased acquisition bandwidth. Here we show that with the calibration of a single polarization state, fiber-based configurations can approach the conceptual simplicity of traditional free-space configurations. We remotely control the polarization state of the light incident at the sample using the eigenpolarization states of a wave plate as a reference, and determine the Jones matrix of the output fiber. We demonstrate this method for polarization-sensitive imaging of biological samples. PMID:25927775

  9. 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.

  10. Identifying the arterial input function from dynamic contrast-enhanced magnetic resonance images using an apex-seeking technique

    NASA Astrophysics Data System (ADS)

    Martel, Anne L.

    2004-04-01

    In order to extract quantitative information from dynamic contrast-enhanced MR images (DCE-MRI) it is usually necessary to identify an arterial input function. This is not a trivial problem if there are no major vessels present in the field of view. Most existing techniques rely on operator intervention or use various curve parameters to identify suitable pixels but these are often specific to the anatomical region or the acquisition method used. They also require the signal from several pixels to be averaged in order to improve the signal to noise ratio, however this introduces errors due to partial volume effects. We have described previously how factor analysis can be used to automatically separate arterial and venous components from DCE-MRI studies of the brain but although that method works well for single slice images through the brain when the blood brain barrier technique is intact, it runs into problems for multi-slice images with more complex dynamics. This paper will describe a factor analysis method that is more robust in such situations and is relatively insensitive to the number of physiological components present in the data set. The technique is very similar to that used to identify spectral end-members from multispectral remote sensing images.

  11. Functional Imaging of the Human Brainstem during Somatosensory Input and Autonomic Output

    PubMed Central

    Henderson, Luke A.; Macefield, Vaughan G.

    2013-01-01

    Over the past half a century, many investigations in experimental animal have explored the functional roles of specific regions in the brainstem. Despite the accumulation of a considerable body of knowledge in, primarily, anesthetized preparations, relatively few studies have explored brainstem function in awake humans. It is important that human brainstem function is explored given that many neurological conditions, from obstructive sleep apnea, chronic pain, and hypertension, likely involve significant changes in the processing of information within the brainstem. Recent advances in the collection and processing of magnetic resonance images have resulted in the possibility of exploring brainstem activity changes in awake healthy individuals and in those with various clinical conditions. We and others have begun to explore changes in brainstem activity in humans during a number of challenges, including cutaneous and muscle pain, as well as during maneuvers that evoke increases in sympathetic nerve activity. More recently we have successfully recorded sympathetic nerve activity concurrently with functional magnetic resonance imaging of the brainstem, which will allow us, for the first time to explore brainstem sites directly responsible for conditions such as hypertension. Since many pathophysiological conditions no doubt involve changes in brainstem function and structure, defining these changes will likely result in a greater ability to develop more effective treatment regimens. PMID:24062670

  12. 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.

  13. High resolution fire danger modeling : integration of quantitative precipitation amount estimates derived from weather radars as an input of FWI

    NASA Astrophysics Data System (ADS)

    Cloppet, E.; Regimbeau, M.

    2009-09-01

    Fire meteo indices provide efficient guidance tools for the prevention, early warning and surveillance of forest fires. The indices are based on meteorological input data. The underlying approach is to exploit meteorological information as fully as possible to model the soil water content, biomass condition and fire danger. Fire meteorological danger is estimated by Météo-France at national level through the use of Fire Weather Index. The fire index services developed within the PREVIEW project (2005-2008) offer for the first time very high resolution mapping of forest fire risk. The high resolution FWI has been implemented in France complementary to the existing EFFIS operated by the Joint Research Center. A new method (ANTILOPE method) of combining precipitation data originating from different sources like rain gauges and weather radar measurements has been applied in the new service. Some of the advantages of this new service are: · Improved detection of local features of fire risk · More accurate analysis of meteorological input data used in forest fire index models providing added value for forest fire risk forecasts · Use of radar precipitation data "as is” utilizing the higher resolution, i.e. avoiding averaging operations The improved accuracy and spatial resolution of the indices provide a powerful early warning tool for national and regional civil protection and fire fighting authorities to alert and initiate forest fire fighting actions and measures.

  14. 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.

  15. The evolution of prefrontal inputs to the cortico-pontine system: diffusion imaging evidence from Macaque monkeys and humans.

    PubMed

    Ramnani, Narender; Behrens, Timothy E J; Johansen-Berg, Heidi; Richter, Marlene C; Pinsk, Mark A; Andersson, Jesper L R; Rudebeck, Peter; Ciccarelli, Olga; Richter, Wolfgang; Thompson, Alan J; Gross, Charles G; Robson, Matthew D; Kastner, Sabine; Matthews, Paul M

    2006-06-01

    The cortico-ponto-cerebellar system is one of the largest projection systems in the primate brain, but in the human brain the nature of the information processing in this system remains elusive. Determining the areas of the cerebral cortex which contribute projections to this system will allow us to better understand information processing within it. Information from the cerebral cortex is conveyed to the cerebellum by topographically arranged fibres in the cerebral peduncle - an important fibre system in which all cortical outputs spatially converge on their way to the cerebellum via the pontine nuclei. Little is known of their anatomical organization in the human brain. New in vivo diffusion imaging and probabilistic tractography methods now offer a way in which input tracts in the cerebral peduncle can be characterized in detail. Here we use these methods to contrast their organization in humans and macaque monkeys. We confirm the dominant contribution of the cortical motor areas to the macaque monkey cerebral peduncle. However, we also present novel anatomical evidence for a relatively large prefrontal contribution to the human cortico-ponto-cerebellar system in the cerebral peduncle. These findings suggest the selective evolution of prefrontal inputs to the human cortico-ponto-cerebellar system. PMID:16120793

  16. Single input state, single–mode fiber–based polarization sensitive optical frequency domain imaging by eigenpolarization referencing

    PubMed Central

    Lippok, Norman; Villiger, Martin; Jun, Chang–Su; Bouma, Brett E.

    2015-01-01

    Fiber–based polarization sensitive OFDI is more challenging than free–space implementations. Using multiple input states, fiber–based systems provide sample birefringence information with the benefit of a flexible sample arm but come at the cost of increased system and acquisition complexity, and either reduce acquisition speed or require increased acquisition bandwidth. Here we show that with the calibration of a single polarization state, fiber–based configurations can approach the conceptual simplicity of traditional free–space configurations. We remotely control the polarization state of the light incident at the sample using the eigenpolarization states of a wave plate as a reference, and determine the Jones matrix of the output fiber. We demonstrate this method for polarization sensitive imaging of biological samples. PMID:25927775

  17. 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, Bruce 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.

  18. 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

  19. 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.

  20. Detection and characterization of local to regional groundwater inputs to rivers, lakes and oceans with electrical imaging (Invited)

    NASA Astrophysics Data System (ADS)

    Cardenas, M. B.; Befus, K. M.; Markowski, M.; Ong, J.; Zamora, P. B.; Siringan, F. P.; Zlotnik, V. A.

    2010-12-01

    Surface water (SW) and groundwater (GW) interact at multiple levels in myriad settings and their interaction is an important hydrogeologic process that impacts ecological and biogeochemical functions. GW discharge and associated mixing with SW in these settings have been challenging to map with sufficient detail and coverage. Three examples are presented on the application of electrical resistivity imaging (ERI) for mapping GW discharge and for understanding SW-GW interactions: (1) a large regulated river, (2) several neighboring lakes, and (3) a fringing coral reef. (1) Time-lapse ERI was conducted at the Colorado River, Texas where the river stage varied by 0.7 m due to dam operations. Submerged and towed electrode cables were used to capture the subsurface mixing dynamics of SW and GW. Using temporal variability in electrical resistivity (ER) signatures, we identified a shallow well-flushed hyporheic zone, a transition zone where SW and GW mix, and a stable deep zone hosting only GW. (2) Towed ER surveys in alkaline lakes in the Nebraska Sand Hills helped distinguishing flow-through lakes, which have decreasing subsurface ER from GW inflow to outflow area, from pure GW discharge lakes, which have uniformly stratified increasing-with-depth ER profiles. (3) More than 30 km of ER profiles collected via towed surveys over a fringing coral reef in the Philippines identified areas of high ER within the reef that coincide with resistive zones in the seawater. Analysis of 222Rn of bottom waters and vertical conductivity-temperature-depth measurements show the persistence of fresh GW input into the ocean where low salinity and high 222Rn areas coincided with high ER areas. A 3D map showing sources and pathways for GW across the reef is developed. ERI is a powerful and convenient tool for mapping GW discharge and SW-GW interactions in rivers, lakes, and oceans.

  1. 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.

  2. 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

  3. 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.

  4. Application research on enhancing near-infrared micro-imaging quality by 2nd derivative

    NASA Astrophysics Data System (ADS)

    Wang, Dong; Ma, Zhi-hong; Zhao, Liu; Wang, Bei-hong; Han, Ping; Pan, Li-gang; Wang, Ji-hua

    2013-08-01

    Near-infrared micro-imaging will not only provide the sample's spatial distribution information, but also the spectroscopic information of each pixel. In this thesis, it took the artificial sample of wheat flour and formaldehyde sodium sulfoxylate distribution given for example to research the data processing method for enhancing the quality of near-infrared micro-imaging. Near-infrared spectroscopic feature of wheat flour and formaldehyde sodium sulfoxylate being studied on, compare correlation imaging and 2nd derivative imaging were applied in the imaging processing of the near-infrared micro-image of the artificial sample. Furthermore, the two methods were combined, i.e. 2nd derivative compare correlation imaging was acquired. The result indicated that the difference of the correlation coefficients between the two substances, i.e. wheat flour and formaldehyde sodium sulfoxylate, and the reference spectrum has been increased from 0.001 in compare correlation image to 0.796 in 2nd derivative compare correlation image respectively, which enhances the imaging quality efficiently. This study will, to some extent, be of important reference significance to near-infrared micro-imaging method research of agricultural products and foods.

  5. Loop Input.

    ERIC Educational Resources Information Center

    Woodward, Tessa

    2003-01-01

    Discusses loop input, a specific type of experiential teacher training process that involves an alignment of the process and content of learning. This concept has gradually gained ground in English language teacher training since 1986 when the term was coined. (Author/VWL)

  6. Ceres Survey Atlas derived from Dawn Framing Camera images

    NASA Astrophysics Data System (ADS)

    Roatsch, Th.; Kersten, E.; Matz, K.-D.; Preusker, F.; Scholten, F.; Jaumann, R.; Raymond, C. A.; Russell, C. T.

    2016-02-01

    The Dawn Framing Camera (FC) acquired almost 900 clear filter images of Ceres with a resolution of about 400 m/pixels during the seven cycles in the Survey orbit in June 2015. We ortho-rectified 42 images from the third cycle and produced a global, high-resolution, controlled mosaic of Ceres. This global mosaic is the basis for a high-resolution Ceres atlas that consists of 3 tiles mapped at a scale of 1:2,000,000. The nomenclature used in this atlas was proposed by the Dawn team and was approved by the International Astronomical Union (IAU). The whole atlas is available to the public through the Dawn GIS web page.

  7. Benzothiadiazole Derivatives as Fluorescence Imaging Probes: Beyond Classical Scaffolds.

    PubMed

    Neto, Brenno A D; Carvalho, Pedro H P R; Correa, Jose R

    2015-06-16

    This Account describes the origins, features, importance, and trends of the use of fluorescent small-molecule 2,1,3-benzothiadiazole (BTD) derivatives as a new class of bioprobes applied to bioimaging analyses of several (live and fixed) cell types. BTDs have been successfully used as probes for a plethora of biological analyses for only a few years, and the impressive responses obtained by using this important class of heterocycle are fostering the development of new fluorescent BTDs and expanding the biological applications of such derivatives. The first use of a fluorescent small-molecule BTD derivative as a selective cellular probe dates back to 2010, and since then impressive advances have been described by us and others. The well-known limitations of classical scaffolds urged the development of new classes of bioprobes. Although great developments have been achieved by using classical scaffolds such as coumarins, BODIPYs, fluoresceins, rhodamines, cyanines, and phenoxazines, there is still much to be done, and BTDs aim to succeed where these dyes have shown their limitations. Important organelles and cell components such as nuclear DNA, mitochondria, lipid droplets, and others have already been successfully labeled by fluorescent small-molecule BTD derivatives. New technological systems that use BTDs as the fluorophores for bioimaging experiments have been described in recent scientific literature. The successful application of BTDs as selective bioprobes has led some groups to explore their potential for use in studying membrane pores or tumor cells under hypoxic conditions. Finally, BTDs have also been used as fluorescent tags to investigate the action mechanism of some antitumor compounds. The attractive photophysical data typically observed for π-extended BTD derivatives is fostering interest in the use of this new class of bioprobes. Large Stokes shifts, large molar extinction coefficients, high quantum yields, high stability when stored in solution or as pure solids, no fading even after long periods of irradiation, bright emissions with no blinking, good signal-to-noise ratios, efficiency to transpose the cell membrane, and irradiation preferentially in the visible-light region are just some features noted by using BTDs. As the pioneering group in the use of fluorescent small-molecule BTDs for bioimaging purposes, we feel pleased to share our experience, results, advances, and personal perspectives with the readers of this Account. The readers will clearly note the huge advantages of using fluorescent BTDs over classical scaffolds, and hopefully they will be inspired and motivated to further BTD technology in the fields of molecular and cellular biology. PMID:25978615

  8. 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 Δz 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.

  9. 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

  10. 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.

  11. Detecting curvatures in digital images using filters derived from differential geometry

    NASA Astrophysics Data System (ADS)

    Toro Giraldo, Juanita

    2015-09-01

    Detection of curvature in digital images is an important theoretical and practical problem in image processing. Many important features in an image are associated with curvature and the detection of such features is reduced to detection and characterization of curvatures. Differential geometry studies many kinds of curvature operators and from these curvature operators is possible to derive powerful filters for image processing which are able to detect curvature in digital images and videos. The curvature operators are formulated in terms of partial differential operators which can be applied to images via convolution with generalized kernels derived from the the Korteweg- de Vries soliton . We present an algorithm for detection of curvature in digital images which is implemented using the Maple package ImageTools. Some experiments were performed and the results were very good. In a future research will be interesting to compare the results using the Korteweg-de Vries soliton with the results obtained using Airy derivatives. It is claimed that the resulting curvature detectors could be incorporated in standard programs for image processing.

  12. 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.

  13. 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.

  14. 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.

  15. Imaging and Tracking of Bone Marrow-Derived Immune and Stem Cells

    PubMed Central

    Zhao, Youbo; Bower, Andrew J.; Graf, Benedikt W.; Boppart, Marni D.; Boppart, Stephen A.

    2014-01-01

    Bone marrow (BM)-derived stem and immune cells play critical roles in maintaining the health, regeneration, and repair of many tissues. Given their important functions in tissue regeneration and therapy, tracking the dynamic behaviors of BM-derived cells has been a long-standing research goal of both biologists and engineers. Because of the complex cellular-level processes involved, real-time imaging technologies that have sufficient spatial and temporal resolution to visualize them are needed. In addition, in order to track cellular dynamics, special attention is needed to account for changes in the microenvironment where the cells reside, for example, tissue contraction, stretching, development, etc. In this chapter, we introduce methods for real-time imaging and longitudinal tracking of BM-derived immune and stem cells in in vivo three-dimensional (3-D) tissue environments with an integrated optical microscope. The integrated microscope combines multiple imaging functions derived from optical coherence tomography (OCT) and multiphoton microscopy (MPM), including optical coherence microscopy (OCM), micro-vasculature imaging, two-photon excited fluorescence (TPEF), and second harmonic generation (SHG) microscopy. Short- and long-term tracking of the dynamic behavior of BM-derived cells involved in cutaneous wound healing and skin grafting in green fluorescent protein (GFP) BM-transplanted mice is demonstrated. Methods and algorithms for nonrigid registration of time-lapse images are introduced, which allows for long-term tracking of cell dynamics over several months. PMID:23737096

  16. A spatial-spectral approach for deriving high signal quality eigenvectors for remote sensing image transformations

    NASA Astrophysics Data System (ADS)

    Rogge, Derek; Bachmann, Martin; Rivard, Benoit; Nielsen, Allan Aasbjerg; Feng, Jilu

    2014-02-01

    Spectral decorrelation (transformations) methods have long been used in remote sensing. Transformation of the image data onto eigenvectors that comprise physically meaningful spectral properties (signal) can be used to reduce the dimensionality of hyperspectral images as the number of spectrally distinct signal sources composing a given hyperspectral scene is generally much less than the number of spectral bands. Determining eigenvectors dominated by signal variance as opposed to noise is a difficult task. Problems also arise in using these transformations on large images, multiple flight-line surveys, or temporal data sets as computational burden becomes significant. In this paper we present a spatial-spectral approach to deriving high signal quality eigenvectors for image transformations which possess an inherently ability to reduce the effects of noise. The approach applies a spatial and spectral subsampling to the data, which is accomplished by deriving a limited set of eigenvectors for spatially contiguous subsets. These subset eigenvectors are compiled together to form a new noise reduced data set, which is subsequently used to derive a set of global orthogonal eigenvectors. Data from two hyperspectral surveys are used to demonstrate that the approach can significantly speed up eigenvector derivation, successfully be applied to multiple flight-line surveys or multi-temporal data sets, derive a representative eigenvector set for the full image data set, and lastly, improve the separation of those eigenvectors representing signal as opposed to noise.

  17. Comprehensive Population-Averaged Arterial Input Function for Dynamic Contrast–Enhanced vMagnetic Resonance Imaging of Head and Neck Cancer

    SciTech Connect

    Onxley, Jennifer D.; Yoo, David S.; Muradyan, Naira; MacFall, James R.; Brizel, David M.; Craciunescu, Oana I.

    2014-07-01

    Purpose: To generate a population-averaged arterial input function (PA-AIF) for quantitative analysis of dynamic contrast-enhanced MRI data in head and neck cancer patients. Methods and Materials: Twenty patients underwent dynamic contrast-enhanced MRI during concurrent chemoradiation therapy. Imaging consisted of 2 baseline scans 1 week apart (B1/B2) and 1 scan after 1 week of chemoradiation therapy (Wk1). Regions of interest (ROIs) in the right and left carotid arteries were drawn on coronal images. Plasma concentration curves of all ROIs were averaged and fit to a biexponential decay function to obtain the final PA-AIF (AvgAll). Right-sided and left-sided ROI plasma concentration curves were averaged separately to obtain side-specific AIFs (AvgRight/AvgLeft). Regions of interest were divided by time point to obtain time-point-specific AIFs (AvgB1/AvgB2/AvgWk1). The vascular transfer constant (K{sub trans}) and the fractional extravascular, extracellular space volume (V{sub e}) for primaries and nodes were calculated using the AvgAll AIF, the appropriate side-specific AIF, and the appropriate time-point-specific AIF. Median K{sub trans} and V{sub e} values derived from AvgAll were compared with those obtained from the side-specific and time-point-specific AIFs. The effect of using individual AIFs was also investigated. Results: The plasma parameters for AvgAll were a{sub 1,2} = 27.11/17.65 kg/L, m{sub 1,2} = 11.75/0.21 min{sup −1}. The coefficients of repeatability (CRs) for AvgAll versus AvgLeft were 0.04 min{sup −1} for K{sub trans} and 0.02 for V{sub e}. For AvgAll versus AvgRight, the CRs were 0.08 min{sup −1} for K{sub trans} and 0.02 for V{sub e}. When AvgAll was compared with AvgB1/AvgB2/AvgWk1, the CRs were slightly higher: 0.32/0.19/0.78 min{sup −1}, respectively, for K{sub trans}; and 0.07/0.08/0.09 for V{sub e}. Use of a PA-AIF was not significantly different from use of individual AIFs. Conclusion: A PA-AIF for head and neck cancer was generated that accounts for differences in right carotid artery versus left carotid artery, day-to-day fluctuations, and early treatment-induced changes. The small CRs obtained for K{sub trans} and V{sub e} indicate that side-specific AIFs are not necessary. However, a time-point-specific AIF may improve pharmacokinetic accuracy.

  18. Auroral energy deposition rate, characteristic electron energy, and ionospheric parameters derived from Dynamics Explorer 1 images

    NASA Technical Reports Server (NTRS)

    Rees, M. H.; Lummerzheim, D.; Roble, R. G.; Winningham, J. D.; Craven, J. D.

    1988-01-01

    Auroral images obtained by the Spin Scan Auroral Imager (SAI) aboard the DE-1 satellite were used to derive auroral energy deposition rate, characteristic electron energy, and ionospheric parameters. The principles involved in the imaging technique and the physical mechanisms that underlie the relationship between the spectral images and the geophysical parameters are discussed together with the methodology for implementing such analyses. It is shown that images obtained with the SAI provide global parameters at 12-min temporal resolution; the spatial resolution is limited by the field of view of a pixel. The analysis of the 12-min images presented yielded a representation of ionospheric parameters that was better than can be obtained using empirical models based on local measurements averaged over long periods of time.

  19. 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

  20. Adjusting the input ultrasound image data and the atherosclerotic plaque detection in the carotid artery by the FOTOMNG system

    PubMed Central

    Ličev, Lačezar; Tomeček, Jan; Farana, Radim

    2014-01-01

    Stroke is the third most frequent cause of death. Specifically, ischemic stroke accounts for the largest group of this kind of cases. Despite all the advances in medical therapeutic methods, no methods that would reliably reduce mortality from ischemic stroke have been found. Prevention is still the most significant way to combat stroke. When the frequent cause of ischemic stroke is atherosclerotic plaque in the carotid artery, its exploration can help to determine the development of the disease. These problems were very extensively discussed in October 2013 during the XVI International Neurosonology Congress in Sofia organized under the auspices of World Research Neurosonology Group, Bulgarian Neurosonology and Cerebral Hemodynamics Association. Our goal was to develop special modules for carotid artery picture processing (AVI file processing, reparation and reconstruction) and modules containing tools for automated carotid artery plaque detection; and to solve its measurement and three-dimensional modelling of the carotid artery and the plaque. New modules were implemented into the FOTOMNG system and tested on appropriate input data files, which verified their functionality and applicability. PMID:26019544

  1. Highly sensitive image-derived indices of water-stressed plants using hyperspectral imaging in SWIR and histogram analysis

    NASA Astrophysics Data System (ADS)

    Kim, David M.; Zhang, Hairong; Zhou, Haiying; Du, Tommy; Wu, Qian; Mockler, Todd C.; Berezin, Mikhail Y.

    2015-11-01

    The optical signature of leaves is an important monitoring and predictive parameter for a variety of biotic and abiotic stresses, including drought. Such signatures derived from spectroscopic measurements provide vegetation indices - a quantitative method for assessing plant health. However, the commonly used metrics suffer from low sensitivity. Relatively small changes in water content in moderately stressed plants demand high-contrast imaging to distinguish affected plants. We present a new approach in deriving sensitive indices using hyperspectral imaging in a short-wave infrared range from 800 nm to 1600 nm. Our method, based on high spectral resolution (1.56 nm) instrumentation and image processing algorithms (quantitative histogram analysis), enables us to distinguish a moderate water stress equivalent of 20% relative water content (RWC). The identified image-derived indices 15XX nm/14XX nm (i.e. 1529 nm/1416 nm) were superior to common vegetation indices, such as WBI, MSI, and NDWI, with significantly better sensitivity, enabling early diagnostics of plant health.

  2. Highly sensitive image-derived indices of water-stressed plants using hyperspectral imaging in SWIR and histogram analysis.

    PubMed

    Kim, David M; Zhang, Hairong; Zhou, Haiying; Du, Tommy; Wu, Qian; Mockler, Todd C; Berezin, Mikhail Y

    2015-01-01

    The optical signature of leaves is an important monitoring and predictive parameter for a variety of biotic and abiotic stresses, including drought. Such signatures derived from spectroscopic measurements provide vegetation indices - a quantitative method for assessing plant health. However, the commonly used metrics suffer from low sensitivity. Relatively small changes in water content in moderately stressed plants demand high-contrast imaging to distinguish affected plants. We present a new approach in deriving sensitive indices using hyperspectral imaging in a short-wave infrared range from 800 nm to 1600 nm. Our method, based on high spectral resolution (1.56 nm) instrumentation and image processing algorithms (quantitative histogram analysis), enables us to distinguish a moderate water stress equivalent of 20% relative water content (RWC). The identified image-derived indices 15XX nm/14XX nm (i.e. 1529 nm/1416 nm) were superior to common vegetation indices, such as WBI, MSI, and NDWI, with significantly better sensitivity, enabling early diagnostics of plant health. PMID:26531782

  3. Highly sensitive image-derived indices of water-stressed plants using hyperspectral imaging in SWIR and histogram analysis

    PubMed Central

    Kim, David M.; Zhang, Hairong; Zhou, Haiying; Du, Tommy; Wu, Qian; Mockler, Todd C.; Berezin, Mikhail Y.

    2015-01-01

    The optical signature of leaves is an important monitoring and predictive parameter for a variety of biotic and abiotic stresses, including drought. Such signatures derived from spectroscopic measurements provide vegetation indices – a quantitative method for assessing plant health. However, the commonly used metrics suffer from low sensitivity. Relatively small changes in water content in moderately stressed plants demand high-contrast imaging to distinguish affected plants. We present a new approach in deriving sensitive indices using hyperspectral imaging in a short-wave infrared range from 800 nm to 1600 nm. Our method, based on high spectral resolution (1.56 nm) instrumentation and image processing algorithms (quantitative histogram analysis), enables us to distinguish a moderate water stress equivalent of 20% relative water content (RWC). The identified image-derived indices 15XX nm/14XX nm (i.e. 1529 nm/1416 nm) were superior to common vegetation indices, such as WBI, MSI, and NDWI, with significantly better sensitivity, enabling early diagnostics of plant health. PMID:26531782

  4. Simultaneous Two-photon In Vivo Imaging of Synaptic Inputs and Postsynaptic Targets in the Mouse Retrosplenial Cortex.

    PubMed

    Łukasiewicz, Kacper; Robacha, Magdalena; Bożycki, Łukasz; Radwanska, Kasia; Czajkowski, Rafał

    2016-01-01

    This video shows the craniotomy procedure that allows chronic imaging of neurons in the mouse retrosplenial cortex (RSC) using in vivo two-photon microscopy in Thy1-GFP transgenic mouse line. This approach creates a possibility to investigate the correlation of behavioural manipulations with changes in neuronal morphology in vivo. The cranial window implantation procedure was considered to be limited only to the easily accessible cortex regions such as the barrel field. Our approach allows visualization of neurons in the highly vascularized RSC. RSC is an important element of the brain circuit responsible for spatial memory, previously deemed to be problematic for in vivo two-photon imaging. The cranial window implantation over the RSC is combined with an injection of mCherry-expressing recombinant adeno-associated virus (rAAV(mCherry)) into the dorsal hippocampus. The expressed mCherry spreads out to axonal projections from the hippocampus to RSC, enabling the visualization of changes in both presynaptic axonal boutons and postsynaptic dendritic spines in the cortex. This technique allows long-term monitoring of experience-dependent structural plasticity in RSC. PMID:27022883

  5. Derivation of planetary topography using multi-image shape-from-shading

    USGS Publications Warehouse

    Lohse, V.; Heipke, C.; Kirk, R.L.

    2006-01-01

    In many cases, the derivation of high-resolution digital terrain models (DTMs) from planetary surfaces using conventional digital image matching is a problem. The matching methods need at least one stereo pair of images with sufficient texture. However, many space missions provide only a few stereo images and planetary surfaces often possess insufficient texture. This paper describes a method for the generation of high-resolution DTMs from planetary surfaces, which has the potential to overcome the described problem. The suggested method, developed by our group, is based on shape-from-shading using an arbitrary number of digital optical images, and is termed "multi-image shape-from-shading" (MI-SFS). The paper contains an explanation of the theory of MI-SFS, followed by a presentation of current results, which were obtained using images from NASA's lunar mission Clementine, and constitute the first practical application with our method using extraterrestrial imagery. The lunar surface is reconstructed under the assumption of different kinds of reflectance models (e.g. Lommel-Seeliger and Lambert). The represented results show that the derivation of a high-resolution DTM of real digital planetary images by means of MI-SFS is feasible. ?? 2006 Elsevier Ltd. All rights reserved.

  6. Image method for the derivation of point sources in elastostatic problems with plane interfaces

    NASA Technical Reports Server (NTRS)

    Fares, Nabil; Li, Victor C.

    1986-01-01

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

  7. 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.

  8. 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.

  9. 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

    2015-09-01

    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.

  10. Two-dimensional superresolution multiple-input multiple-output and inverse synthetic aperture radar imaging based on spatial frequency ambiguity resolving

    NASA Astrophysics Data System (ADS)

    Yang, Jianchao; Su, Weimin; Gu, Hong

    2015-01-01

    Combining multiple-input multiple-output (MIMO) radar and inverse synthetic aperture radar (ISAR) techniques can reduce the number of antennas used and shorten the radar integrated time compared with the single-channel ISAR for the same cross-range resolution. In existing MIMO-ISAR processing, the echoes of different sensors are rearranged into an equivalent single-channel ISAR signal. A new method without echo rearrangement is proposed for two-dimensional (2-D) MIMO-ISAR imaging. A 2-D frequency estimation algorithm based on Unitary ESPRIT and projection transformation is used to obtain the spatial and Doppler frequencies of scatterers, and a high cross-range resolution can be achieved. The relationship between the two frequencies is exploited to resolve the ambiguity of spatial frequency. The analysis and simulation results show that, compared with the existing method, the proposed method can decrease the relative rotation angle (or integrated time) required for imaging. Thus, this method is more suitable for imaging targets with limited rotation or high maneuvering.

  11. Validation of spectral sky radiance derived from all-sky camera images - a case study

    NASA Astrophysics Data System (ADS)

    Tohsing, K.; Schrempf, M.; Riechelmann, S.; Seckmeyer, G.

    2014-07-01

    Spectral sky radiance (380-760 nm) is derived from measurements with a hemispherical sky imager (HSI) system. The HSI consists of a commercial compact CCD (charge coupled device) camera equipped with a fish-eye lens and provides hemispherical sky images in three reference bands such as red, green and blue. To obtain the spectral sky radiance from these images, non-linear regression functions for various sky conditions have been derived. The camera-based spectral sky radiance was validated using spectral sky radiance measured with a CCD spectroradiometer. The spectral sky radiance for complete distribution over the hemisphere between both instruments deviates by less than 20% at 500 nm for all sky conditions and for zenith angles less than 80°. The reconstructed spectra of the wavelengths 380-760 nm between both instruments at various directions deviate by less than 20% for all sky conditions.

  12. Validation of spectral sky radiance derived from all-sky camera images - a case study

    NASA Astrophysics Data System (ADS)

    Tohsing, K.; Schrempf, M.; Riechelmann, S.; Seckmeyer, G.

    2014-01-01

    Spectral sky radiance (380-760 nm) is derived from measurements with a Hemispherical Sky Imager (HSI) system. The HSI consists of a commercial compact CCD (charge coupled device) camera equipped with a fish-eye lens and provides hemispherical sky images in three reference bands such as red, green and blue. To obtain the spectral sky radiance from these images non-linear regression functions for various sky conditions have been derived. The camera-based spectral sky radiance was validated by spectral sky radiance measured with a CCD spectroradiometer. The spectral sky radiance for complete distribution over the hemisphere between both instruments deviates by less than 20% at 500 nm for all sky conditions and for zenith angles less than 80°. The reconstructed spectra of the wavelength 380 nm to 760 nm between both instruments at various directions deviate by less then 20% for all sky conditions.

  13. 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.

  14. Multispectral image classification of MRI data using an empirically-derived clustering algorithm

    SciTech Connect

    Horn, K.M.; Osbourn, G.C.; Bouchard, A.M.; Sanders, J.A. |

    1998-08-01

    Multispectral image analysis of magnetic resonance imaging (MRI) data has been performed using an empirically-derived clustering algorithm. This algorithm groups image pixels into distinct classes which exhibit similar response in the T{sub 2} 1st and 2nd-echo, and T{sub 1} (with ad without gadolinium) MRI images. The grouping is performed in an n-dimensional mathematical space; the n-dimensional volumes bounding each class define each specific tissue type. The classification results are rendered again in real-space by colored-coding each grouped class of pixels (associated with differing tissue types). This classification method is especially well suited for class volumes with complex boundary shapes, and is also expected to robustly detect abnormal tissue classes. The classification process is demonstrated using a three dimensional data set of MRI scans of a human brain tumor.

  15. Using Geotags to Derive Rich Tag-Clouds for Image Annotation

    NASA Astrophysics Data System (ADS)

    Joshi, Dhiraj; Luo, Jiebo; Yu, Jie; Lei, Phoury; Gallagher, Andrew

    Geotagging has become popular for many multimedia applications. In this chapter, we present an integrated and intuitive system for location-driven tag suggestion, in the form of tag-clouds, for geotagged photos. Potential tags from multiple sources are extracted and weighted. Sources include points of interest (POI) tags from a public Geographic Names Information System (GNIS) database, community tags from Flickr® pictures, and personal tags shared through users' own, family, and friends' photo collections. To increase the effectiveness of GNIS POI tags, bags of place-name tags are first retrieved, clustered, and then re-ranked using a combined tf-idf and spatial distance criteria. The community tags from photos taken in the vicinity of the input geotagged photo are ranked according to distance and visual similarity to the input photo. Personal tags from other personally related photos inherently carry a significant weight due more to their high relevance than to both the generic place-name tags and community tags, and are ranked by weights that decay over time and distance differences. Finally, a rich set of the most relevant location-driven tags is presented to the user in the form of individual tag clouds under the three mentioned source categories. The tag clouds act as intuitive suggestions for tagging an input image. We also discuss quantitative and qualitative findings from a user study that we conducted. Evaluation has revealed the respective benefits of the three categories toward the effectiveness of the integrated tag suggestion system.

  16. Thermokarst Lake Gyre Flow Speed and Direction Derivation Using Image Matching from Sequential Satellite Images

    NASA Astrophysics Data System (ADS)

    Zhan, S.; Wang, S.; Beck, R. A.; Liu, H.; Hinkel, K. M.

    2014-12-01

    Thermokarst lakes on the Arctic Coastal Plain of northern Alaska are closely coupled with the regional climate through energy, water and carbon budgets. These lakes exhibit striking elongated shapes perpendicular to the prevailing wind direction. This has led to the hypothesis that the expansion of lakes is caused by thermomechanical processes induced by wind-driven water circulation. The predominant bimodal wind regime in the region (easterly and westerly wind) redistributes lake sediment towards the west and east shores to form protective littoral shelves while the north and south shores are preferentially eroded. Previous research on wind-driven circulation in thermokarst lakes was mainly based on in situ studies which can only collect sparse measurements and is time-consuming. Examination of satellite imagery clearly reveals the wide-spread presence of gyres in thermokarst lakes. It allows the study of gyres and other circulation patterns at both lake and regional scales. This study examines the movement (speed, direction) of a 10-km-wide gyre using a Landsat-7 and an ASTER scene taken about 40 minutes apart. These two images are matched using a robust image matching technique based on cross-correlation. Flow speed and direction for the gyre are extracted from the images and are compared with the in situ measurements collected during previous field work. This study provides insight into the evolution of thermokarst lakes and their interaction with the local climate by quantifying gyre circulation rates over entire lakes.

  17. 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

  18. Resolution and shutter speed measurements of an MCPII with a 270-ps whole image shutter for a point-source input

    SciTech Connect

    Thomas, M.C.; Yates, G.J.; Zagarino, P.

    1995-07-01

    The modulation transfer function (MF) of a shuttered, 18-mm-diameter, proximity-focused microchemical-plate image intensifier (MCPII) was measured as a function of time in the shutter sequence. Electrical gate pulses were delivered to the MCPII with microstrip impedance transformers for reduced pulse dispersion and reflections. Using 30 ps FWHM, 600 nm pulses from a sync-pumped dye, argon-ion laser as a probe, the MCPII`s shutter speed for point-source (6-{mu}m-diameter) illumination and 230 ps FWHM, {minus}590 V gate pulses was measured to be between 200 and 250 ps FWHM. The MF of the MCPII was measured by analyzing the point spread function (PSF) for inputs at several different locations on the MCPII and at different times in the shuttering sequence. The best 50% MF resolution of 16.2 lp/mm was found with illumination near the edge where the gate pulse enters the MCPII and at 120 ps into the shutter sequence. The whole image (18-mm-diameter) shutter speed (off-to-off) of the MCPII was measured to be 270 ps.

  19. 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.

  20. 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

  1. Geo-accurate model extraction from three-dimensional image-derived point clouds

    NASA Astrophysics Data System (ADS)

    Nilosek, David; Sun, Shaohui; Salvaggio, Carl

    2012-06-01

    A methodology is proposed for automatically extracting primitive models of buildings in a scene from a three-dimensional point cloud derived from multi-view depth extraction techniques. By exploring the information provided by the two-dimensional images and the three-dimensional point cloud and the relationship between the two, automated methods for extraction are presented. Using the inertial measurement unit (IMU) and global positioning system (GPS) data that accompanies the aerial imagery, the geometry is derived in a world-coordinate system so the model can be used with GIS software. This work uses imagery collected by the Rochester Institute of Technology's Digital Imaging and Remote Sensing Laboratory's WASP sensor platform. The data used was collected over downtown Rochester, New York. Multiple target buildings have their primitive three-dimensional model geometry extracted using modern point-cloud processing techniques.

  2. The methods research of deriving bamboo information based on IKONOS image

    NASA Astrophysics Data System (ADS)

    Guo, Zheng; Jiang, Hong; Chen, Jian; Cheng, Miaomiao; Jiang, Zishan

    2009-10-01

    Bamboo is an important forest resource at sub-tropical regions in China, which continuous expansion has taken place in China during the last 20 years. Monitoring its distribution has important significance. It provide a possibility that we can extract accurate information among vegetation types as result of detailed texture features, patterns, optical information can be obtained from IKONOS image. In this paper, Anji Country in Zhejiang province was selected, deriving bamboo information from IKONOS image by using Iterative Self-Organizing Data Analysis Technique(ISODATA) classify method, Decision Tree method based on NDVI and texture and Object-oriented classification algorithm based on texture and spectral bands were discussed. The results showed that Decision Tree method based on NDVI and texture demonstrated high accuracy (Kappa=0.7428). Additional, Object-oriented classification algorithm based on texture and spectral bands suggested the highest user's accuracy 93% and producer's 78% at deriving bamboo information, which can be adapted to deriving bamboo information from IKONOS image at subtropical regions in China.

  3. Hyaluronic acid and its derivatives in drug delivery and imaging: Recent advances and challenges.

    PubMed

    Tripodo, Giuseppe; Trapani, Adriana; Torre, Maria Luisa; Giammona, Gaetano; Trapani, Giuseppe; Mandracchia, Delia

    2015-11-01

    Hyaluronic acid (HA) is a biodegradable, biocompatible, nontoxic, and non-immunogenic glycosaminoglycan used for various biomedical applications. The interaction of HA with the CD44 receptor, whose expression is elevated on the surface of many types of tumor cells, makes this polymer a promising candidate for intracellular delivery of imaging and anticancer agents exploiting a receptor-mediated active targeting strategy. Therefore, HA and its derivatives have been most investigated for the development of several carrier systems intended for cancer diagnosis and therapy. Nonetheless, different and important delivery applications of the polysaccharide have also been described, including gene and peptide/protein drugs delivery. The aim of this review was to provide an overview of the existing recent literature on the use of HA and its derivatives for drug delivery and imaging. Notable attention is given to nanotheranostic systems obtained after conjugation of HA to nanocarriers as quantum dots, carbon nanotubes and graphene. Meanwhile, attention is also paid to some challenging aspects that need to be addressed in order to allow translation of preclinical models based on HA and its derivatives for drug delivery and imaging purposes to clinical testing and further their development. PMID:26614559

  4. Derivation of the scan time requirement for maintaining a consistent PET image quality

    NASA Astrophysics Data System (ADS)

    Kim, Jin Su; Lee, Jae Sung; Kim, Seok-Ki

    2015-05-01

    Objectives: the image quality of PET for larger patients is relatively poor, even though the injection dose is optimized considering the NECR characteristics of the PET scanner. This poor image quality is due to the lower level of maximum NECR that can be achieved in these large patients. The aim of this study was to optimize the PET scan time to obtain a consistent PET image quality regardless of the body size, based on the relationship between the patient specific NECR (pNECR) and body weight. Methods: eighty patients (M/F=53/27, body weight: 059 ± 1 kg) underwent whole-body FDG PET scans using a Philips GEMINI GS PET/CT scanner after an injection of 0.14 mCi/kg FDG. The relationship between the scatter fraction (SF) and body weight was determined by repeated Monte Carlo simulations using a NEMA scatter phantom, the size of which varied according to the relationship between the abdominal circumference and body weight. Using this information, the pNECR was calculated from the prompt and delayed PET sinograms to obtain the prediction equation of NECR vs. body weight. The time scaling factor (FTS) for the scan duration was finally derived to make PET images with equivalent SNR levels. Results: the SF and NECR had the following nonlinear relationships with the body weight: SF=0.15 ṡ body weight0.3 and NECR = 421.36 (body weight)-0.84. The equation derived for FTS was 0.01ṡ body weight + 0.2, which means that, for example, a 120-kg person should be scanned 1.8 times longer than a 70 kg person, or the scan time for a 40-kg person can be reduced by 30%. Conclusion: the equation of the relative time demand derived in this study will be useful for maintaining consistent PET image quality in clinics.

  5. Camera motion tracking of real bronchoscope using epipolar geometry analysis and CT-derived bronchoscopic images

    NASA Astrophysics Data System (ADS)

    Deguchi, Daisuke; Mori, Kensaku; Hasegawa, Jun-ichi; Toriwaki, Jun-ichiro; Takabatake, Hirotsugu; Natori, Hiroshi

    2002-04-01

    This paper describes a method to track camera motion of a real endoscope by using epipolar geometry analysis and CT derived virtual endoscopic images. A navigation system for a flexible endoscope guides medical doctors by providing navigation information during endoscope examinations. This paper tries to estimate the motion from an endoscopic video image based on epipolar geometry analysis and image registration between virtual endoscopic (VE) and real endoscopic (RE) images. The method consists of three parts: (a) direct estimation of camera motion by using epipolar geometry analysis, (b) precise estimation by using image registration, and (c) detection of bubble frames for avoiding miss-registration. First we calculate optical flow patterns from two consecutive frames. The camera motion is computed by substituting the obtained flows into the epipolar equations. Then we find the observation parameter of a virtual endoscopy system that generates the most similar endoscopic view to the current RE frame. We execute these processes for all frames of RE videos except for frames where bubbles appear. We applied the proposed method to RE videos of three patients who have CT images. The experimental results show the method can track camera motion for over 500 frames continuously in the best case.

  6. 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.

  7. Characterisation of radioiodinated flavonoid derivatives for SPECT imaging of cerebral prion deposits

    PubMed Central

    Fuchigami, Takeshi; Yamashita, Yuki; Kawasaki, Masao; Ogawa, Ayaka; Haratake, Mamoru; Atarashi, Ryuichiro; Sano, Kazunori; Nakagaki, Takehiro; Ubagai, Kaori; Ono, Masahiro; Yoshida, Sakura; Nishida, Noriyuki; Nakayama, Morio

    2015-01-01

    Prion diseases are fatal neurodegenerative diseases characterised by deposition of amyloid plaques containing abnormal prion protein aggregates (PrPSc). This study aimed to evaluate the potential of radioiodinated flavonoid derivatives for single photon emission computed tomography (SPECT) imaging of PrPSc. In vitro binding assays using recombinant mouse PrP (rMoPrP) aggregates revealed that the 4-dimethylamino-substituted styrylchromone derivative (SC-NMe2) had higher in vitro binding affinity (Kd = 24.5 nM) and capacity (Bmax = 36.3 pmol/nmol protein) than three other flavonoid derivatives (flavone, chalcone, and aurone). Fluorescent imaging using brain sections from mouse-adapted bovine spongiform encephalopathy (mBSE)-infected mice demonstrated that SC-NMe2 clearly labelled PrPSc-positive prion deposits in the mice brain. Two methoxy SC derivatives, SC-OMe and SC-(OMe)2, also showed high binding affinity for rMoPrP aggregates with Ki values of 20.8 and 26.6 nM, respectively. In vitro fluorescence and autoradiography experiments demonstrated high accumulation of [125I]SC-OMe and [125I]SC-(OMe)2 in prion deposit-rich regions of the mBSE-infected mouse brain. SPECT/computed tomography (CT) imaging and ex vivo autoradiography demonstrated that [123I]SC-OMe showed consistent brain distribution with the presence of PrPSc deposits in the mBSE-infected mice brain. In conclusion, [123I]SC-OMe appears a promising SPECT radioligand for monitoring prion deposit levels in the living brain. PMID:26669576

  8. Characterisation of radioiodinated flavonoid derivatives for SPECT imaging of cerebral prion deposits.

    PubMed

    Fuchigami, Takeshi; Yamashita, Yuki; Kawasaki, Masao; Ogawa, Ayaka; Haratake, Mamoru; Atarashi, Ryuichiro; Sano, Kazunori; Nakagaki, Takehiro; Ubagai, Kaori; Ono, Masahiro; Yoshida, Sakura; Nishida, Noriyuki; Nakayama, Morio

    2015-01-01

    Prion diseases are fatal neurodegenerative diseases characterised by deposition of amyloid plaques containing abnormal prion protein aggregates (PrP(Sc)). This study aimed to evaluate the potential of radioiodinated flavonoid derivatives for single photon emission computed tomography (SPECT) imaging of PrP(Sc). In vitro binding assays using recombinant mouse PrP (rMoPrP) aggregates revealed that the 4-dimethylamino-substituted styrylchromone derivative (SC-NMe2) had higher in vitro binding affinity (Kd = 24.5 nM) and capacity (Bmax = 36.3 pmol/nmol protein) than three other flavonoid derivatives (flavone, chalcone, and aurone). Fluorescent imaging using brain sections from mouse-adapted bovine spongiform encephalopathy (mBSE)-infected mice demonstrated that SC-NMe2 clearly labelled PrP(Sc)-positive prion deposits in the mice brain. Two methoxy SC derivatives, SC-OMe and SC-(OMe)2, also showed high binding affinity for rMoPrP aggregates with Ki values of 20.8 and 26.6 nM, respectively. In vitro fluorescence and autoradiography experiments demonstrated high accumulation of [(125)I]SC-OMe and [(125)I]SC-(OMe)2 in prion deposit-rich regions of the mBSE-infected mouse brain. SPECT/computed tomography (CT) imaging and ex vivo autoradiography demonstrated that [(123)I]SC-OMe showed consistent brain distribution with the presence of PrP(Sc) deposits in the mBSE-infected mice brain. In conclusion, [(123)I]SC-OMe appears a promising SPECT radioligand for monitoring prion deposit levels in the living brain. PMID:26669576

  9. Automatic derivation of programs for image processing from natural language descriptions

    NASA Astrophysics Data System (ADS)

    Ren, Fuji; Zaima, Yasumichi

    1999-10-01

    In this paper we describe AIDPG, an interactive prototype system, which derives computer programs from their natural language descriptions. AIDPG shows how to analyze natural language, resolve ambiguities using knowledge, and generates programs. AIDPG consists of a natural language input model, a natural language analysis model, a program generation model (PGG-Model) and a human machine interface control model. The PGG model has three sub-models, program structure manage sub-model, a data structure and type manage sub- model, and program base manage sub-model. We used an arithmetic problem, which, described in Japanese, was passed to AIDPG and got run-possible C programs. Although AIDPG is basic currently we got a significant result.

  10. 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.

  11. 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. Institute of Northern Forestry, Fairbanks, AK )

    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.

  12. (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.

  13. Characterising the composition of waste-derived fuels using a novel image analysis tool.

    PubMed

    Peddireddy, S; Longhurst, P J; Wagland, S T

    2015-06-01

    An experimental study was completed using a previously developed and innovative image analysis approach, which has been applied here to shredded waste materials representative of waste-derived fuels. Waste components were collected from source-segregated recycling containers and shredded to <150 mm. These materials were then used to produce 3× samples of different composition. The samples were spread to represent materials on a conveyor belt, and multiple images of each sample were captured using 10×10 cm and 20×20 cm quadrats. The images were processed using ERDAS Imagine software to determine the area covered by each waste component. This coverage was converted into a mass using density data determined as part of this study, yielding a determined composition which was then compared with the known composition of the samples. The image analysis results indicated a strong correlation with the actual values (mean r=0.89). The area coverage of the sample (10×10 cm or 20×20 cm) contributes to the accuracy as the dot-grid approach used with the particle size within the samples may result in components not being sufficiently monitored. This manuscript presents initial results of the application of an adapted innovative image-based method, and critically assesses how the technique could be improved and developed in the future. PMID:25827256

  14. 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

  15. Development of (68)Ga-labeled multivalent nitroimidazole derivatives for hypoxia imaging.

    PubMed

    Seelam, Sudhakara Reddy; Lee, Ji Youn; Lee, Yun-Sang; Hong, Mi Kyung; Kim, Young Joo; Banka, Vinay Kumar; Lee, Dong Soo; Chung, June-Key; Jeong, Jae Min

    2015-12-15

    Radiolabeled nitroimidazole (NI) derivatives have been extensively studied for imaging hypoxia. To increase the hypoxic tissue uptake, we developed (68)Ga-labeled agents based on mono-, bis-, and trisnitroimidazole conjugates with the chelating agent 1,4,7-triazacyclononane-1,4,7-tris[methyl(2-carboxyethyl)phosphinic acid] (TRAP). All the three agents showed high radiolabeling yields (>96%) and were found to be stable up to 4h in prepared medium at room temperature and in human serum at 37°C. The trivalent agent showed a significant increase in hypoxic to normoxic uptake ratio (p <0.005) according to the in vitro cell uptake experiments. Immunohistochemical analysis confirmed the presence of hypoxia in xenografted CT26 tumor tissue. The trivalent derivative ((68)Ga-3: 0.17±0.04, (68)Ga-4: 0.33±0.04, (68)Ga-5: 0.45±0.09, and (68)Ga-6: 0.47±0.05% ID/g) showed the highest uptake by tumor cells according to the biodistribution studies in CT-26 xenografted mice. All the nitroimidazole derivatives showed significantly higher uptake by tumor cells than the control agent (p <0.05) at 1h post-injection. The trivalent derivative ((68)Ga-3: 0.10±0.06; (68)Ga-4: 0.20±0.06; (68)Ga-5: 0.33±0.08; (68)Ga-6: 0.59±0.09) also showed the highest standard uptake value for tumor cells at 1h post-injection in animal PET studies using CT-26 xenografted mice. In conclusion, we successfully synthesized multivalent (68)Ga-labeled NI derivatives for imaging hypoxia. Among them, the trivalent agent showed the highest tumor uptake in biodistribution and animal PET studies. PMID:26643217

  16. Feasibility of poly(ethylene glycol) derivatives as diagnostic drug carriers for tumor imaging.

    PubMed

    Kanazaki, Kengo; Sano, Kohei; Makino, Akira; Yamauchi, Fumio; Takahashi, Atsushi; Homma, Tsutomu; Ono, Masahiro; Saji, Hideo

    2016-03-28

    Poly(ethylene glycol) (PEG) is an artificial but biocompatible hydrophilic polymer that has been widely used in clinical products. To evaluate the feasibility of using PEG derivative itself as a tumor imaging carrier via an enhanced permeability and retention (EPR) effect, we prepared indium-111-labeled PEG ((111)In-DTPA-PEG) and indocyanine green (ICG)-labeled PEG (ICG-PEG) with PEG molecular weights of 5-40kDa and investigated their in vivo biodistribution in colon26 tumor-bearing mice. Thereafter, single-photon emission computed tomography (SPECT) and photoacoustic (PA) imaging studies were performed. The in vivo biodistribution studies demonstrated increased tumor uptake and a prolongation of circulation half-life as the molecular weight of PEG increased. Although the observed differences in in vivo biodistribution were dependent on the labeling method ((111)In or ICG), the tumor-to-normal tissue ratios were comparable. Because PEG-based probes with a molecular weight of 20kDa (PEG20) showed a preferable biodistribution (highest accumulation among tissues excised and relatively high tumor-to-blood ratios), an imaging study using (111)In-DTPA-PEG20 and ICG-PEG20 was performed. Colon26 tumors inoculated in the right shoulder were clearly visualized by SPECT 24h after administration. Furthermore, PA imaging using ICG-PEG20 also detected tumor regions, and the detected PA signals increased in proportion with the injected dose. These results suggest that PEG derivatives (20kDa) serve as robust diagnostic drug carriers for tumor imaging. PMID:26869546

  17. Assessment of image-derived risk factors for natural course of unruptured cerebral aneurysms.

    PubMed

    Ramachandran, Manasi; Retarekar, Rohini; Raghavan, Madhavan L; Berkowitz, Benjamin; Dickerhoff, Benjamin; Correa, Tatiana; Lin, Steve; Johnson, Kevin; Hasan, David; Ogilvy, Christopher; Rosenwasser, Robert; Torner, James; Bogason, Einar; Stapleton, Christopher J; Harbaugh, Robert E

    2016-02-01

    OBJECT The goal of this prospective longitudinal study was to test whether image-derived metrics can differentiate unruptured aneurysms that will become unstable (grow and/or rupture) from those that will remain stable. METHODS One hundred seventy-eight patients harboring 198 unruptured cerebral aneurysms for whom clinical observation and follow-up with imaging surveillance was recommended at 4 clinical centers were prospectively recruited into this study. Imaging data (predominantly CT angiography) at initial presentation was recorded. Computational geometry was used to estimate numerous metrics of aneurysm morphology that described the size and shape of the aneurysm. The nonlinear, finite element method was used to estimate uniform pressure-induced peak wall tension. Computational fluid dynamics was used to estimate blood flow metrics. The median follow-up period was 645 days. Longitudinal outcome data on these aneurysm patients-whether their aneurysms grew or ruptured (the unstable group) or remained unchanged (the stable group)-was documented based on follow-up at 4 years after the beginning of recruitment. RESULTS Twenty aneurysms (10.1%) grew, but none ruptured. One hundred forty-nine aneurysms (75.3%) remained stable and 29 (14.6%) were lost to follow-up. None of the metrics-including aneurysm size, nonsphericity index, peak wall tension, and low shear stress area-differentiated the stable from unstable groups with statistical significance. CONCLUSIONS The findings in this highly selected group do not support the hypothesis that image-derived metrics can predict aneurysm growth in patients who have been selected for observation and imaging surveillance. If aneurysm shape is a significant determinant of invasive versus expectant management, selection bias is a key limitation of this study. PMID:26381246

  18. The Impact of Arterial Input Function Determination Variations on Prostate Dynamic Contrast-Enhanced Magnetic Resonance Imaging Pharmacokinetic Modeling: A Multicenter Data Analysis Challenge

    PubMed Central

    Huang, Wei; Chen, Yiyi; Fedorov, Andriy; Li, Xia; Jajamovich, Guido H.; Malyarenko, Dariya I.; Aryal, Madhava P.; LaViolette, Peter S.; Oborski, Matthew J.; O'Sullivan, Finbarr; Abramson, Richard G.; Jafari-Khouzani, Kourosh; Afzal, Aneela; Tudorica, Alina; Moloney, Brendan; Gupta, Sandeep N.; Besa, Cecilia; Kalpathy-Cramer, Jayashree; Mountz, James M.; Laymon, Charles M.; Muzi, Mark; Schmainda, Kathleen; Cao, Yue; Chenevert, Thomas L.; Taouli, Bachir; Yankeelov, Thomas E.; Fennessy, Fiona; Li, Xin

    2016-01-01

    Dynamic contrast-enhanced MRI (DCE-MRI) has been widely used in tumor detection and therapy response evaluation. Pharmacokinetic analysis of DCE-MRI time-course data allows estimation of quantitative imaging biomarkers such as Ktrans(rate constant for plasma/interstitium contrast reagent (CR) transfer) and ve (extravascular and extracellular volume fraction). However, the use of quantitative DCE-MRI in clinical prostate imaging islimited, with uncertainty in arterial input function (AIF, i.e., the time rate of change of the concentration of CR in the blood plasma) determination being one of the primary reasons. In this multicenter data analysis challenge to assess the effects of variations in AIF quantification on estimation of DCE-MRI parameters, prostate DCE-MRI data acquired at one center from 11 prostate cancer patients were shared among nine centers. Each center used its site-specific method to determine the individual AIF from each data set and submitted the results to the managing center. Along with a literature population averaged AIF, these AIFs and their reference-tissue-adjusted variants were used by the managing center to perform pharmacokinetic analysis of the DCE-MRI data sets using the Tofts model (TM). All other variables including tumor region of interest (ROI) definition and pre-contrast T1 were kept the same to evaluate parameter variations caused by AIF variations only. Considerable pharmacokinetic parameter variations were observed with the within-subject coefficient of variation (wCV) of Ktrans obtained with unadjusted AIFs as high as 0.74. AIF-caused variations were larger in Ktrans than ve and both were reduced when reference-tissue-adjusted AIFs were used. The parameter variations were largely systematic, resulting in nearly unchanged parametric map patterns. The CR intravasation rate constant, kep (= Ktrans/ve), was less sensitive to AIF variation than Ktrans (wCV for unadjusted AIFs: 0.45 for kep vs. 0.74 for Ktrans), suggesting that it might be a more robust imaging biomarker of prostate microvasculature than Ktrans. PMID:27200418

  19. Bioluminescence Reporter Gene Imaging Characterize Human Embryonic Stem Cell-Derived Teratoma Formation

    PubMed Central

    Su, Weijun; Zhou, Manqian; Zheng, Yizhou; Fan, Yan; Han, Zhongchao; Kong, Deling; Wu, Joseph C.; Xiang, Rong; Li, Zongjin

    2011-01-01

    Human embryonic stem (hES) cells are capable of differentiation into virtually all cell types and hold tremendous potential as cell sources for regenerative therapies. However, teratoma formation can be the main obstacle for hES cells therapy. In order to understand the biology and physiology of hES cells teratoma formation, we investigated the angiogenic process within teratomas and characterized teratoma cells. In this study, hES cells transduced with double fusion reporter gene that consists of firefly luciferase and enhanced green fluorescent protein (Fluc-eGFP) were injected into hind limbs of SCID mice and performed longitudinal bioluminescence imaging on these animals. To test angiogenic contribution of teratoma from host or hES cells, human and mouse endothelial cells marker CD31 was stained respectively. To further explore the characterization of teratoma derived cells, flow cytometry analysis was carried out and GFP+/SSEA-4+ cells were isolated and subcultured. Then, we re-injected the isolated GFP+/SSEA-4+ teratoma cells into SCID mice and observed by imaging. Our results show that the reporter gene imaging is an ideal technology for monitoring long-term stem cell viability, death, and proliferation. Teratomas contained vasculatures are from hES cells and host. hESCs derived teratomas express a high level of undifferentiated marker SSEA-4 and CD56, and subcultured GFP+/SSEA-4+ cells had similar expression pattern comparing to undifferentiated hES cells, except for a very high level of CD56 and a little lower expression of undifferentiated markers, such as SSEA-3, SSEA-4, TRA-1-60, and TRA-1-81. Moreover, the SSEA-4+ teratoma cells can form teratomas in SCID mice, and this type teratomas grow at a lower rate compared to teratomas derived from hES cells, and are more differentiated. PMID:21328457

  20. A New Highly Reactive and Low Lipophilicity Fluorine-18 Labeled Tetrazine Derivative for Pretargeted PET Imaging.

    PubMed

    Keinänen, Outi; Li, Xiang-Guo; Chenna, Naveen K; Lumen, Dave; Ott, Jennifer; Molthoff, Carla F M; Sarparanta, Mirkka; Helariutta, Kerttuli; Vuorinen, Tapani; Windhorst, Albert D; Airaksinen, Anu J

    2016-01-14

    A new (18)F-labeled tetrazine derivative was developed aiming at optimal radiochemistry, fast reaction kinetics in inverse electron-demand Diels-Alder cycloaddition (IEDDA), and favorable pharmacokinetics for in vivo bioorthogonal chemistry. The radiolabeling of the tetrazine was achieved in high yield, purity, and specific activity under mild reaction conditions via conjugation with 5-[(18)F]fluoro-5-deoxyribose, providing a glycosylated tetrazine derivative with low lipophilicity. The (18)F-tetrazine showed fast reaction kinetics toward the most commonly used dienophiles in IEDDA reactions. It exhibited excellent chemical and enzymatic stability in mouse plasma and in phosphate-buffered saline (pH 7.41). Biodistribution in mice revealed favorable pharmacokinetics with major elimination via urinary excretion. The results indicate that the glycosylated (18)F-labeled tetrazine is an excellent candidate for in vivo bioorthogonal chemistry applications in pretargeted PET imaging approaches. PMID:26819667

  1. Near-infrared-fluorescence imaging of lymph nodes by using liposomally formulated indocyanine green derivatives.

    PubMed

    Toyota, Taro; Fujito, Hiromichi; Suganami, Akiko; Ouchi, Tomoki; Ooishi, Aki; Aoki, Akira; Onoue, Kazutaka; Muraki, Yutaka; Madono, Tomoyuki; Fujinami, Masanori; Tamura, Yutaka; Hayashi, Hideki

    2014-01-15

    Liposomally formulated indocyanine green (LP-ICG) has drawn much attention as a highly sensitive near-infrared (NIR)-fluorescence probe for tumors or lymph nodes in vivo. We synthesized ICG derivatives tagged with alkyl chains (ICG-Cn), and we examined NIR-fluorescence imaging for lymph nodes in the lower extremities of mice by using liposomally formulated ICG-Cn (LP-ICG-Cn) as well as conventional liposomally formulated ICG (LP-ICG) and ICG. Analysis with a noninvasive preclinical NIR-fluorescence imaging system revealed that LP-ICG-Cn accumulates in only the popliteal lymph node 1h after injection into the footpad, whereas LP-ICG and ICG accumulate in the popliteal lymph node and other organs like the liver. This result indicates that LP-ICG-Cn is a useful NIR-fluorescence probe for noninvasive in vivo bioimaging, especially for the sentinel lymph node. PMID:24393719

  2. 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.

  3. Tryptophan PET Imaging of the Kynurenine Pathway in Patient-Derived Xenograft Models of Glioblastoma.

    PubMed

    Guastella, Anthony R; Michelhaugh, Sharon K; Klinger, Neil V; Kupsky, William J; Polin, Lisa A; Muzik, Otto; Juhász, Csaba; Mittal, Sandeep

    2016-01-01

    Increasing evidence demonstrates the immunosuppressive kynurenine pathway's (KP) role in the pathophysiology of human gliomas. To study the KP in vivo, we used the noninvasive molecular imaging tracer α-[(11)C]-methyl-l-tryptophan (AMT). The AMT-positron emission tomography (PET) has shown high uptake in high-grade gliomas and predicted survival in patients with recurrent glioblastoma (GBM). We generated patient-derived xenograft (PDX) models from dissociated cells, or tumor fragments, from 5 patients with GBM. Mice bearing subcutaneous tumors were imaged with AMT-PET, and tumors were analyzed to detect the KP enzymes indoleamine 2,3-dioxygenase (IDO) 1, IDO2, tryptophan 2,3-dioxygenase, kynureninase, and kynurenine 3-monooxygenase. Overall, PET imaging showed robust tumoral AMT uptake in PDX mice with prolonged tracer accumulation over 60 minutes, consistent with AMT trapping seen in humans. Immunostained tumor tissues demonstrated positive detection of multiple KP enzymes. Furthermore, intracranial implantation of GBM cells was performed with imaging at both 9 and 14 days postimplant, with a marked increase in AMT uptake at 14 days and a corresponding high level of tissue immunostaining for KP enzymes. These results indicate that our PDX mouse models recapitulate human GBM, including aberrant tryptophan metabolism, and offer an in vivo system for development of targeted therapeutics for patients with GBM. PMID:27151136

  4. Fluorescent carbon nanoparticles derived from natural materials of mango fruit for bio-imaging probes

    NASA Astrophysics Data System (ADS)

    Jeong, Chan Jin; Roy, Arup Kumer; Kim, Sung Han; Lee, Jung-Eun; Jeong, Ji Hoon; Insik; Park, Sung Young

    2014-11-01

    Water soluble fluorescent carbon nanoparticles (FCP) obtained from a single natural source, mango fruit, were developed as unique materials for non-toxic bio-imaging with different colors and particle sizes. The prepared FCPs showed blue (FCP-B), green (FCP-G) and yellow (FCP-Y) fluorescence, derived by the controlled carbonization method. The FCPs demonstrated hydrodynamic diameters of 5-15 nm, holding great promise for clinical applications. The biocompatible FCPs demonstrated great potential in biological fields through the results of in vitro imaging and in vivo biodistribution. Using intravenously administered FCPs with different colored particles, we precisely defined the clearance and biodistribution, showing rapid and efficient urinary excretion for safe elimination from the body. These findings therefore suggest the promising possibility of using natural sources for producing fluorescent materials.Water soluble fluorescent carbon nanoparticles (FCP) obtained from a single natural source, mango fruit, were developed as unique materials for non-toxic bio-imaging with different colors and particle sizes. The prepared FCPs showed blue (FCP-B), green (FCP-G) and yellow (FCP-Y) fluorescence, derived by the controlled carbonization method. The FCPs demonstrated hydrodynamic diameters of 5-15 nm, holding great promise for clinical applications. The biocompatible FCPs demonstrated great potential in biological fields through the results of in vitro imaging and in vivo biodistribution. Using intravenously administered FCPs with different colored particles, we precisely defined the clearance and biodistribution, showing rapid and efficient urinary excretion for safe elimination from the body. These findings therefore suggest the promising possibility of using natural sources for producing fluorescent materials. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr04805a

  5. Partial correlation analyses of global diffusion tensor imaging-derived metrics in glioblastoma multiforme: Pilot study

    PubMed Central

    Cortez-Conradis, David; Rios, Camilo; Moreno-Jimenez, Sergio; Roldan-Valadez, Ernesto

    2015-01-01

    AIM: To determine existing correlates among diffusion tensor imaging (DTI)-derived metrics in healthy brains and brains with glioblastoma multiforme (GBM). METHODS: Case-control study using DTI data from brain magnetic resonance imaging of 34 controls (mean, 41.47; SD, ± 21.94 years; range, 21-80 years) and 27 patients with GBM (mean, SD; 48.41 ± 15.18 years; range, 18-78 years). Image postprocessing using FSL software calculated eleven tensor metrics: fractional (FA) and relative anisotropy; pure isotropic (p) and anisotropic diffusions (q), total magnitude of diffusion (L); linear (Cl), planar (Cp) and spherical tensors (Cs); mean (MD), axial (AD) and radial diffusivities (RD). Partial correlation analyses (controlling the effect of age and gender) and multivariate Mancova were performed. RESULTS: There was a normal distribution for all metrics. Comparing healthy brains vs brains with GBM, there were significant very strong bivariate correlations only depicted in GBM: [FA↔Cl (+)], [FA↔q (+)], [p↔AD (+)], [AD↔MD (+)], and [MD↔RD (+)]. Among 56 pairs of bivariate correlations, only seven were significantly different. The diagnosis variable depicted a main effect [F-value (11, 23) = 11.842, P ≤ 0.001], with partial eta squared = 0.850, meaning a large effect size; age showed a similar result. The age also had a significant influence as a covariate [F (11, 23) = 10.523, P < 0.001], with a large effect size (partial eta squared = 0.834). CONCLUSION: DTI-derived metrics depict significant differences between healthy brains and brains with GBM, with specific magnitudes and correlations. This study provides reference data and makes a contribution to decrease the underlying empiricism in the use of DTI parameters in brain imaging. PMID:26644826

  6. Enhancing Proprioceptive Input to Motoneurons Differentially Affects Expression of Neurotrophin 3 and Brain-Derived Neurotrophic Factor in Rat Hoffmann-Reflex Circuitry

    PubMed Central

    Gajewska-Woźniak, Olga; Skup, Małgorzata; Kasicki, Stefan; Ziemlińska, Ewelina; Czarkowska-Bauch, Julita

    2013-01-01

    The importance of neurotrophin 3 (NT-3) for motor control prompted us to ask the question whether direct electrical stimulation of low-threshold muscle afferents, strengthening the proprioceptive signaling, could effectively increase the endogenous pool of this neurotrophin and its receptor TrkC in the Hoffmann-reflex (H-reflex) circuitry. The effects were compared with those of brain-derived neurotrophic factor (BDNF) and its TrkB receptor. Continuous bursts of stimuli were delivered unilaterally for seven days, 80 min daily, by means of a cuff-electrode implanted over the tibial nerve in awake rats. The H-reflex was recorded in the soleus muscle to control the strength of stimulation. Stimulation aimed at activation of Ia fibers produced a strong increase of NT-3 protein, measured with ELISA, in the lumbar L3-6 segments of the spinal cord and in the soleus muscle. This stimulation exerted much weaker effect on BDNF protein level which slightly increased only in L3-6 segments of the spinal cord. Increased protein level of NT-3 and BDNF corresponded to the changes of NT-3 mRNA and BDNF mRNA expression in L3-6 segments but not in the soleus muscle. We disclosed tissue-specificity of TrkC mRNA and TrkB mRNA responses. In the spinal cord TrkC and TrkB transcripts tended to decrease, whereas in the soleus muscle TrkB mRNA decreased and TrkC mRNA expression strongly increased, suggesting that stimulation of Ia fibers leads to sensitization of the soleus muscle to NT-3 signaling. The possibility of increasing NT-3/TrkC signaling in the neuromuscular system, with minor effects on BDNF/TrkB signaling, by means of low-threshold electrical stimulation of peripheral nerves, which in humans might be applied in non-invasive way, offers an attractive therapeutic tool. PMID:23776573

  7. Enhancing proprioceptive input to motoneurons differentially affects expression of neurotrophin 3 and brain-derived neurotrophic factor in rat hoffmann-reflex circuitry.

    PubMed

    Gajewska-Woźniak, Olga; Skup, Małgorzata; Kasicki, Stefan; Ziemlińska, Ewelina; Czarkowska-Bauch, Julita

    2013-01-01

    The importance of neurotrophin 3 (NT-3) for motor control prompted us to ask the question whether direct electrical stimulation of low-threshold muscle afferents, strengthening the proprioceptive signaling, could effectively increase the endogenous pool of this neurotrophin and its receptor TrkC in the Hoffmann-reflex (H-reflex) circuitry. The effects were compared with those of brain-derived neurotrophic factor (BDNF) and its TrkB receptor. Continuous bursts of stimuli were delivered unilaterally for seven days, 80 min daily, by means of a cuff-electrode implanted over the tibial nerve in awake rats. The H-reflex was recorded in the soleus muscle to control the strength of stimulation. Stimulation aimed at activation of Ia fibers produced a strong increase of NT-3 protein, measured with ELISA, in the lumbar L3-6 segments of the spinal cord and in the soleus muscle. This stimulation exerted much weaker effect on BDNF protein level which slightly increased only in L3-6 segments of the spinal cord. Increased protein level of NT-3 and BDNF corresponded to the changes of NT-3 mRNA and BDNF mRNA expression in L3-6 segments but not in the soleus muscle. We disclosed tissue-specificity of TrkC mRNA and TrkB mRNA responses. In the spinal cord TrkC and TrkB transcripts tended to decrease, whereas in the soleus muscle TrkB mRNA decreased and TrkC mRNA expression strongly increased, suggesting that stimulation of Ia fibers leads to sensitization of the soleus muscle to NT-3 signaling. The possibility of increasing NT-3/TrkC signaling in the neuromuscular system, with minor effects on BDNF/TrkB signaling, by means of low-threshold electrical stimulation of peripheral nerves, which in humans might be applied in non-invasive way, offers an attractive therapeutic tool. PMID:23776573

  8. COLLINARUS: collection of image-derived non-linear attributes for registration using splines

    NASA Astrophysics Data System (ADS)

    Chappelow, Jonathan; Bloch, B. Nicolas; Rofsky, Neil; Genega, Elizabeth; Lenkinski, Robert; DeWolf, William; Viswanath, Satish; Madabhushi, Anant

    2009-02-01

    We present a new method for fully automatic non-rigid registration of multimodal imagery, including structural and functional data, that utilizes multiple texutral feature images to drive an automated spline based non-linear image registration procedure. Multimodal image registration is significantly more complicated than registration of images from the same modality or protocol on account of difficulty in quantifying similarity between different structural and functional information, and also due to possible physical deformations resulting from the data acquisition process. The COFEMI technique for feature ensemble selection and combination has been previously demonstrated to improve rigid registration performance over intensity-based MI for images of dissimilar modalities with visible intensity artifacts. Hence, we present here the natural extension of feature ensembles for driving automated non-rigid image registration in our new technique termed Collection of Image-derived Non-linear Attributes for Registration Using Splines (COLLINARUS). Qualitative and quantitative evaluation of the COLLINARUS scheme is performed on several sets of real multimodal prostate images and synthetic multiprotocol brain images. Multimodal (histology and MRI) prostate image registration is performed for 6 clinical data sets comprising a total of 21 groups of in vivo structural (T2-w) MRI, functional dynamic contrast enhanced (DCE) MRI, and ex vivo WMH images with cancer present. Our method determines a non-linear transformation to align WMH with the high resolution in vivo T2-w MRI, followed by mapping of the histopathologic cancer extent onto the T2-w MRI. The cancer extent is then mapped from T2-w MRI onto DCE-MRI using the combined non-rigid and affine transformations determined by the registration. Evaluation of prostate registration is performed by comparison with the 3 time point (3TP) representation of functional DCE data, which provides an independent estimate of cancer extent. The set of synthetic multiprotocol images, acquired from the BrainWeb Simulated Brain Database, comprises 11 pairs of T1-w and proton density (PD) MRI of the brain. Following the application of a known warping to misalign the images, non-rigid registration was then performed to recover the original, correct alignment of each image pair. Quantitative evaluation of brain registration was performed by direct comparison of (1) the recovered deformation field to the applied field and (2) the original undeformed and recovered PD MRI. For each of the data sets, COLLINARUS is compared with the MI-driven counterpart of the B-spline technique. In each of the quantitative experiments, registration accuracy was found to be significantly (p < 0.05) for COLLINARUS compared with MI-driven B-spline registration. Over 11 slices, the mean absolute error in the deformation field recovered by COLLINARUS was found to be 0.8830 mm.

  9. 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.

  10. 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

  11. Imagery-derived modulation transfer function and its applications for underwater imaging

    NASA Astrophysics Data System (ADS)

    Hou, Weilin; Weidemann, Alan D.; Gray, Deric J.; Fournier, Georges R.

    2007-09-01

    The main challenge working with underwater imagery results from both rapid decay of signals due to absorption, which leads to poor signal to noise returns, and the blurring caused by strong scattering by the water itself and constituents within, especially particulates. The modulation transfer function (MTF) of an optical system gives the detailed and precise information regarding the system behavior. Underwater imageries can be better restored with the knowledge of the system MTF or the point spread function (PSF), the Fourier transformed equivalent, extending the performance range as well as the information retrieval from underwater electro-optical system. This is critical in many civilian and military applications, including target and especially mine detection, search and rescue, and diver visibility. This effort utilizes test imageries obtained by the Laser Underwater Camera Imaging Enhancer (LUCIE) from Defense Research and Development Canada (DRDC), during an April-May 2006 trial experiment in Panama City, Florida. Imaging of a standard resolution chart with various spatial frequencies were taken underwater in a controlled optical environment, at varying distances. In-water optical properties during the experiment were measured, which included the absorption and attenuation coefficients, particle size distribution, and volume scattering function. Resulting images were preprocessed to enhance signal to noise ratio by averaging multiple frames, and to remove uneven illumination at target plane. The MTF of the medium was then derived from measurement of above imageries, subtracting the effect of the camera system. PSFs converted from the measured MTF were then used to restore the blurred imageries by different deconvolution methods. The effects of polarization from source to receiver on resulting MTFs were examined and we demonstrate that matching polarizations do enhance system transfer functions. This approach also shows promise in deriving medium optical properties including absorption and attenuation.

  12. Labeling pluripotent stem cell-derived neural progenitors with iron oxide particles for magnetic resonance imaging.

    PubMed

    Sart, Sébastien; Bejarano, Fabian Calixto; Yan, Yuanwei; Grant, Samuel C; Li, Yan

    2015-01-01

    Due to the unlimited proliferation capacity and the unique differentiation ability of pluripotent stem cells (PSCs), including both embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs), large numbers of PSC-derived cell products are in demand for applications in drug screening, disease modeling, and especially cell therapy. In stem cell-based therapy, tracking transplanted cells with magnetic resonance imaging (MRI) has emerged as a powerful technique to reveal cell survival and distribution. This chapter illustrated the basic steps of labeling PSC-derived neural progenitors (NPs) with micron-sized particles of iron oxide (MPIO, 0.86 μm) for MRI analysis. The protocol described PSC expansion and differentiation into NPs, and the labeling of the derived cells either after replating on adherent surface or in suspension. The labeled cells can be analyzed using in vitro MRI analysis. The methods presented here can be easily adapted for cell labeling in cell processing facilities under current Good Manufacturing Practices (cGMP). The iron oxide-labeled NPs can be used for cellular monitoring of in vitro cultures and in vivo transplantation. PMID:25304204

  13. 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.

  14. Label-free imaging of metabolism and oxidative stress in human induced pluripotent stem cell-derived cardiomyocytes

    PubMed Central

    Datta, Rupsa; Heylman, Christopher; George, Steven C.; Gratton, Enrico

    2016-01-01

    In this work we demonstrate a label-free optical imaging technique to assess metabolic status and oxidative stress in human induced pluripotent stem cell-derived cardiomyocytes by two-photon fluorescence lifetime imaging of endogenous fluorophores. Our results show the sensitivity of this method to detect shifts in metabolism and oxidative stress in the cardiomyocytes upon pathological stimuli of hypoxia and cardiotoxic drugs. This non-invasive imaging technique could prove beneficial for drug development and screening, especially for in vitro cardiac models created from stem cell-derived cardiomyocytes and to study the pathogenesis of cardiac diseases and therapy. PMID:27231614

  15. 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.

  16. The evaluation of NIR-absorbing porphyrin derivatives as contrast agents in photoacoustic imaging.

    PubMed

    Abuteen, Akram; Zanganeh, Saeid; Akhigbe, Joshua; Samankumara, Lalith P; Aguirre, Andres; Biswal, Nrusingh; Braune, Marcel; Vollertsen, Anke; Röder, Beate; Brückner, Christian; Zhu, Quing

    2013-11-14

    Six free base tetrapyrrolic chromophores, three quinoline-annulated porphyrins and three morpholinobacteriochlorins, that absorb light in the near-IR range and possess, in comparison to regular porphyrins, unusually low fluorescence emission and (1)O2 quantum yields were tested with respect to their efficacy as novel molecular photo-acoustic imaging contrast agents in a tissue phantom, providing an up to ∼2.5-fold contrast enhancement over that of the benchmark contrast agent ICG. The testing protocol compares the photoacoustic signal output strength upon absorption of approximately the same light energy. Some relationships between photophysical parameters of the dyes and the resulting photoacoustic signal strength could be derived. PMID:24071709

  17. Synthesis, and Fluorescence Properties of Coumarin and Benzocoumarin Derivatives Conjugated Pyrimidine Scaffolds for Biological Imaging Applications.

    PubMed

    Al-Masoudi, Najim A; Al-Salihi, Niran J; Marich, Yossra A; Markus, Timo

    2015-11-01

    Series of coumarin and 5,6-benzomcomarin substituted pyrimidine derivatives 11-15 and 22-25 were synthesized, aiming to develop new imaging fluorescent agents. Analogously, treatment of 4-chloropyrimidine analog 16 with coumarin 3-carbohyrazide 5 under MWI condition followed by boiling with NH4OAc in HOAc furnished coumarin-1,2,4-triazolo-pyrimidine analog 18. The fluorescence property was investigated spectrophotometrically in MeOH with Rhodamine 6G as standard dye. All the compounds showed emission in the region between 331 and 495 nm. The quantum yield of all the compounds were found to be weak, except methyl benzocoumarin 3-carboxylate 22 which showed (ΦF = 0.98) in comparison to Rhodamine 6G as standard (ΦF = 0.95). PMID:26477837

  18. A seed expanding cluster algorithm for deriving upwelling areas on sea surface temperature images

    NASA Astrophysics Data System (ADS)

    Nascimento, Susana; Casca, Sérgio; Mirkin, Boris

    2015-12-01

    In this paper a novel clustering algorithm is proposed as a version of the seeded region growing (SRG) approach for the automatic recognition of coastal upwelling from sea surface temperature (SST) images. The new algorithm, one seed expanding cluster (SEC), takes advantage of the concept of approximate clustering due to Mirkin (1996, 2013) to derive a homogeneity criterion in the format of a product rather than the conventional difference between a pixel value and the mean of values over the region of interest. It involves a boundary-oriented pixel labeling so that the cluster growing is performed by expanding its boundary iteratively. The starting point is a cluster consisting of just one seed, the pixel with the coldest temperature. The baseline version of the SEC algorithm uses Otsu's thresholding method to fine-tune the homogeneity threshold. Unfortunately, this method does not always lead to a satisfactory solution. Therefore, we introduce a self-tuning version of the algorithm in which the homogeneity threshold is locally derived from the approximation criterion over a window around the pixel under consideration. The window serves as a boundary regularizer. These two unsupervised versions of the algorithm have been applied to a set of 28 SST images of the western coast of mainland Portugal, and compared against a supervised version fine-tuned by maximizing the F-measure with respect to manually labeled ground-truth maps. The areas built by the unsupervised versions of the SEC algorithm are significantly coincident over the ground-truth regions in the cases at which the upwelling areas consist of a single continuous fragment of the SST map.

  19. Plasma Distribution in Mercury's Magnetosphere Derived from MESSENGER Magnetometer and Fast Imaging Plasma Spectrometer Observations

    NASA Technical Reports Server (NTRS)

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

    2014-01-01

    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 10months 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 approximately 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.

  20. 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.

  1. Synthesis and evaluation of (18)F-trifluoroborate derivatives of triphenylphosphonium for myocardial perfusion imaging.

    PubMed

    Zhang, Zhengxing; Jenni, Silvia; Zhang, Chengcheng; Merkens, Helen; Lau, Joseph; Liu, Zhibo; Perrin, David M; Bénard, François; Lin, Kuo-Shyan

    2016-04-01

    Four trifluoroborate derivatives of phosphonium cations 2a-d were radiolabeled with fluorine-18 ((18)F) and evaluated for imaging myocardial perfusion with positron emission tomography (PET). Tracers were radiolabeled simply via (18)F-(19)F isotope exchange reaction in acidic (pH 2) aqueous solution. On average, [(18)F]2a-d were obtained in 10-17% non-decay-corrected radiochemical yield with 25.9-48.1GBq/μmol specific activity, and >96% radiochemical purity. In vitro stability study showed no decomposition of [(18)F]2a-d after being incubated in mouse plasma for up to 2h. Myocardial uptake in mice was visualized in PET images by using [(18)F]2b-d but not [(18)F]2a. [(18)F]2a-d were stable against in vivo defluorination as no significant bone uptake was observed. Despite sub-optimal heart uptake of [(18)F]2b-d, we successfully demonstrated that (18)F-(19)F isotope exchange reaction on trifluoroborates could be a promising strategy for the design of potential (18)F-labeled tracers even for intracellular targets. PMID:26922139

  2. Automatic Identification and Truncation of Boundary Outlets in Complex Imaging-Derived Biomedical Geometries

    SciTech Connect

    Jiao, Xiangmin; Einstein, Daniel R.; Dyedov, Volodymyr; Carson, James P.

    2009-09-01

    Fast and accurate reconstruction of imaging-derived geometries and subsequent quality mesh generation for biomedical computation are enabling technologies for both clinical and research simulations. Often, the transformation of image to mesh is the rate-limiting step, requiring arduous manual manipulations. A challenging part of this process is the introduction of computable, orthogonal boundary patches, namely the outlets, into treed structures, such as vasculature, arterial or airway trees. Herein, we present efficient and robust algorithms for automatically identifying and truncating the outlets for complex biomedical geometries. Our approach is based on a conceptual decomposition of objects into three different types of local structures, including tips, segments, and branches, where the tips determine the outlets. We define the tips by introducing a novel geometric concept called the average interior center of curvature (AICC), and identify those that are physically stable and numerically noise resistant through successive inflation and deflation tests. We compute well-defined orthogonal planes, which truncate the tips into outlets. The rims of the outlets are then connected into curves, and the outlets are then closed using Delaunay triangulation with the curves as the boundary constraints. Our approach is efficient, with near linear time complexity. We illustrate the effectiveness and robustness of our approach with a variety of complex lung and coronary artery geometries.

  3. Monosodium glutamate derived tricolor fluorescent carbon nanoparticles for cell-imaging application.

    PubMed

    Zheng, Nannan; Ding, Sha; Zhou, Xingping

    2016-06-01

    Fluorescent carbon nanoparticle (FCN) is a new type of carbon-based materials. Because of its wide raw material sources, excellent optical properties and good biocompatibility, FCN is getting more and more attentions. However, its synthesis from resources at low cost under mild conditions is still a challenge. Here we report a novel and simple method derived from monosodium glutamate carbonization to make tricolor fluorescent carbon nanoparticles with an average size below 10nm, a high yield up to 35.2% based on the carbon content in the resource, a long life-time of 3.71ns, and a high fluorescence quantum yield up to 51.5% by using quinine sulfate as the standard substance. We discovered that the fluorescent stability of the FCNs was very excellent under UV irradiation for hours in aqueous solutions of pH ranged from 2.0 to 9.0. The cell viability tested under a pretty high concentration of FCNs indicated their safety for biological applications. Based on their high fluorescence quantum efficiency and the advantages mentioned above, these FCNs were then used for cell imaging and exhibited a perfect performance under 3 kinds of excitation bands (UV, blue, and green lights). Thus, they can be practically applied to immune labeling and imaging in vivo in the near future. PMID:26945164

  4. 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.

  5. Derivatives of dibenzothiophene for PET imaging of α7-Nicotinic Acetylcholine Receptors

    PubMed Central

    Gao, Yongjun; Kellar, Kenneth J.; Yasuda, Robert P.; Tran, Thao; Xiao, Yingxian; Dannals, Robert F.; Horti, Andrew G.

    2013-01-01

    A new series of derivatives of 3-(1,4-diazabicyclo[3.2.2]nonan-4-yl)dibenzo[b,d]thiophene 5,5-dioxide with high binding affinities and selectivity for α7-nicotinic acetylcholine receptors (α7-nAChRs) (Ki = 0.4 – 20 nM) has been synthesized for PET imaging of α7-nAChRs. Two radiolabeled members of the series [18F]7a (Ki = 0.4 nM) and [18F]7c (Ki = 1.3 nM) were synthesized. [18F]7a and [18F]7c readily entered the mouse brain and specifically labeled α7-nAChRs. The α7-nAChR selective ligand 1 (SSR180711) blocked the binding of [18F]7a in the mouse brain in a dose-dependent manner. The mouse blocking studies with non-α7-nAChR CNS drugs demonstrated that [18F]7a is highly α7-nAChR selective. In agreement with its binding affinity the binding potential of [18F]7a (BPND = 5.3 – 8.0) in control mice is superior to previous α7-nAChR PET radioligands. Thus, [18F]7a displays excellent imaging properties in mice and has been chosen for further evaluation as a potential PET radioligand for imaging of α7-nAChR in non-human primates. PMID:24050653

  6. 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

  7. Synthesis of [18F]-labelled Maltose Derivatives as PET Tracers for Imaging Bacterial Infection

    PubMed Central

    Namavari, Mohammad; Gowrishankar, Gayatri; Hoehne, Aileen; Jouannot, Erwan; Gambhir, Sanjiv S

    2015-01-01

    Purpose To develop novel positron emission tomography (PET) agents for visualization and therapy monitoring of bacterial infections. Procedures It is known that maltose and maltodextrins are energy sources for bacteria. Hence, 18F-labelled maltose derivatives could be a valuable tool for imaging bacterial infections. We have developed methods to synthesize 4-O-(α-D-glucopyranosyl)-6-deoxy-6-[18F]fluoro-D-glucopyranoside (6-[18F]fluoromaltose) and 4-O-(α-D-glucopyranosyl)-1-deoxy-1-[18F]fluoro-D-glucopyranoside (1-[18F]fluoromaltose) as bacterial infection PET imaging agents. 6-[18F]fluoromaltose was prepared from precursor 1,2,3-tri-O-acetyl-4-O-(2′,3′,-di-O-acetyl-4′,6′-benzylidene-α-D-glucopyranosyl)-6-deoxy-6-nosyl-D-glucopranoside (5). The synthesis involved the radio-fluorination of 5 followed by acidic and basic hydrolysis to give 6-[18F]fluoromaltose. In an analogous procedure, 1-[18F]fluoromaltose was synthesized from 2,3, 6-tri-O-acetyl-4-O-(2′,3′,4′,6-tetra-O-acetyl-α-D-glucopyranosyl)-1-deoxy-1-O-triflyl-D-glucopranoside (9). Stability of 6-[18F]fluoromaltose in phosphate-buffered saline (PBS) and human and mouse serum at 37 °C was determined. Escherichia coli uptake of 6-[18F]fluoromaltose was examined. Results A reliable synthesis of 1- and 6-[18F]fluoromaltose has been accomplished with 4–6 and 5–8 % radiochemical yields, respectively (decay-corrected with 95 % radiochemical purity). 6-[18F]fluoromaltose was sufficiently stable over the time span needed for PET studies (~96 % intact compound after 1-h and ~65 % after 2-h incubation in serum). Bacterial uptake experiments indicated that E. coli transports 6-[18F]fluoromaltose. Competition assays showed that the uptake of 6-[18F]fluoromaltose was completely blocked by co-incubation with 1 mM of the natural substrate maltose. Conclusion We have successfully synthesized 1- and 6-[18F]fluoromaltose via direct fluorination of appropriate protected maltose precursors. Bacterial uptake experiments in E. coli and stability studies suggest a possible application of 6-[18F]fluoromaltose as a new PET imaging agent for visualization and monitoring of bacterial infections. PMID:25277604

  8. Hyperpolarized (3)He magnetic resonance imaging-derived pulmonary pressure-volume curves.

    PubMed

    Choy, Stephen; Wheatley, Andrew; McCormack, David G; Parraga, Grace

    2010-08-01

    We aimed to evaluate the potential for the use of hyperpolarized helium-3 magnetic resonance imaging (MRI) apparent diffusion coefficient (ADC) surrogates of alveolar size, together with literature-based morphological parameters in a theoretical model of lung mechanics to simulate noninvasive transpulmonary pressure-volume curves. Fourteen ex-smokers with chronic obstructive pulmonary disease (COPD) (n = 8 stage II, n = 6 stage III/IV COPD) and five age-matched never-smokers, provided written, informed consent and were evaluated at baseline and 26 + or - 2 mo later (n = 15 subjects) using plethysmography, spirometry, and (3)He MRI at 3.0 T. Total lung capacity, residual volume, and literature-based morphological parameters were used with alveolar volumes derived from (3)He ADC to simulate noninvasive pressure-volume curves. The resultant anterior-posterior transpulmonary pressure gradient was significantly decreased for stage II COPD (P < 0.01) and stage III COPD subjects (P < 0.001) compared with healthy volunteers. Both COPD subgroups showed increased alveolar radius compared with healthy subjects (P < 0.01, stage II COPD; P < 0.001, stage III COPD). In addition, surface area and surface tension were significantly increased in stage III COPD compared with healthy volunteers (P < 0.01). These results suggest that (3)He MRI provides a potential noninvasive approach to evaluate lung mechanics regionally and further supports the use of ADC values as a regional noninvasive probe of pulmonary microstructure and compliance. PMID:20538846

  9. Natural-color and color-infrared image mosaics of the Colorado River corridor in Arizona derived from the May 2009 airborne image collection

    USGS Publications Warehouse

    Davis, Philip A.

    2013-01-01

    The Grand Canyon Monitoring and Research Center (GCMRC) of the U.S. Geological Survey (USGS) periodically collects airborne image data for the Colorado River corridor within Arizona (fig. 1) to allow scientists to study the impacts of Glen Canyon Dam water release on the corridor’s natural and cultural resources. These data are collected from just above Glen Canyon Dam (in Lake Powell) down to the entrance of Lake Mead, for a total distance of 450 kilometers (km) and within a 500-meter (m) swath centered on the river’s mainstem and its seven main tributaries (fig. 1). The most recent airborne data collection in 2009 acquired image data in four wavelength bands (blue, green, red, and near infrared) at a spatial resolution of 20 centimeters (cm). The image collection used the latest model of the Leica ADS40 airborne digital sensor (the SH52), which uses a single optic for all four bands and collects and stores band radiance in 12-bits. Davis (2012) reported on the performance of the SH52 sensor and on the processing steps required to produce the nearly flawless four-band image mosaic (sectioned into map tiles) for the river corridor. The final image mosaic has a total of only 3 km of surface defects in addition to some areas of cloud shadow because of persistent inclement weather during data collection. The 2009 four-band image mosaic is perhaps the best image dataset that exists for the entire Arizona part of the Colorado River. Some analyses of these image mosaics do not require the full 12-bit dynamic range or all four bands of the calibrated image database, in which atmospheric scattering (or haze) had not been removed from the four bands. To provide scientists and the general public with image products that are more useful for visual interpretation, the 12-bit image data were converted to 8-bit natural-color and color-infrared images, which also removed atmospheric scattering within each wavelength-band image. The conversion required an evaluation of the histograms of each band’s digital-number population within each map tile throughout the corridor and the determination of the digital numbers corresponding to the lower and upper one percent of the picture-element population within each map tile. Visual examination of the image tiles that were given a 1-percent stretch (whereby the lower 1- percent 12-bit digital number is assigned an 8-bit value of zero and the upper 1-percent 12-bit digital number is assigned an 8-bit value of 255) indicated that this stretch sufficiently removed atmospheric scattering, which provided improved image clarity and true natural colors for all surface materials. The lower and upper 1-percent, 12-bit digital numbers for each wavelength-band image in the image tiles exhibit erratic variations along the river corridor; the variations exhibited similar trends in both the lower and upper 1-percent digital numbers for all four wavelength-band images (figs. 2–5). The erratic variations are attributed to (1) daily variations in atmospheric water-vapor content due to monsoonal storms, (2) variations in channel water color due to variable sediment input from tributaries, and (3) variations in the amount of topographic shadows within each image tile, in which reflectance is dominated by atmospheric scattering. To make the surface colors of the stretched, 8-bit images consistent among adjacent image tiles, it was necessary to average both the lower and upper 1-percent digital values for each wavelength-band image over 20 river miles to subdue the erratic variations. The average lower and upper 1-percent digital numbers for each image tile (figs. 2–5) were used to convert the 12-bit image values to 8-bit values and the resulting 8-bit four-band images were stored as natural-color (red, green, and blue wavelength bands) and color-infrared (near-infrared, red, and green wavelength bands) images in embedded geotiff format, which can be read and used by most geographic information system (GIS) and image-processing software. The tiff world files (tfw) are provided, even though they are generally not needed for most software to read an embedded geotiff image. All image data are projected in the State Plane (SP) map projection using the central Arizona zone (202) and the North American Datum of 1983 (NAD83). The map-tile scheme used to segment the corridor image mosaic followed the standard USGS quarter-quadrangle (QQ) map borders, but the high resolution (20 cm) of the images required further quarter segmentation (QQQ) of the standard QQ tiles, where the image mosaic covered a large fraction of a QQ map tile (segmentation shown in (figure 6), where QQ_1 to QQ_4 shows the number convention used to designate a quarter of a QQ tile). To minimize the size of each image tile, each image or map tile was subset to only include that part of the tile that had image data. In addition, some QQQ image tiles within a QQ tile were combined when adjacent QQQ map tiles were small. Thus, some image tiles consist of combinations of QQQ map tiles, some consist of an entire QQ map tile, and some consist of two adjoining QQ map tiles. The final image tiles number 143, which is a large number of files to list on the Internet for both the natural-color and color-infrared images. Thus, the image tiles were placed in seven file folders based on the one-half-degree geographic boundaries within the study area (fig. 7). The map tiles in each file folder were compressed to minimize folder size for more efficient downloading. The file folders are sequentially referred to as zone 1 through zone 7, proceeding down river (fig. 7). The QQ designations of the image tiles contained within each folder or zone are shown on the index map for each respective zone (figs. 8–14).

  10. A statistical protocol for describing global land-cover characterizations derived from remotely-sensed images

    NASA Astrophysics Data System (ADS)

    Fosnight, Eugene Alan

    Statistical measures are evaluated and recommended for use in a protocol to describe land-cover characterizations (often with more than 100 classes), to identify classes needing further evaluation, and to support mapping the land-cover characterization classes into user-specified land-cover classes (often with fewer than 20 classes). The data sets studied are the Land-Cover Characterization database derived from AVHRR images (1992--1993) for the conterminous U.S., the USGS Land-Use Land-Cover database derived from aerial photography (1960s and 1970s), and the USFS coordinated ground-sampled Land-Cover Characterization Validation database (1993--1994). A set of overall, class-specific and class-pairs measures of association with distinct statistical properties is incorporated into the protocol. Three overall measures, Proportional Reduction in Error (PRE), Proportion of Explained Variance (PEV), and Cramer's V, quantify the relationship between land-cover characterizations and landcover classifications. Using a Monte Carlo simulation, at sample sizes less than 0.1% the population parameters are no longer contained within the interquartile range of the estimates. Standardized conditional variants of PEV and PRE are used to identify classes whose distributions of counts differ statistically from the marginal frequencies. The Chi-square, correlation coefficient, Yule's Q and deviance residuals quantify the associations between land-cover characterization and land-cover classification class-pairs. The Chi-square statistic identifies statistically independent class-pairs. The other three measures allow class-pairs to be ranked. The protocol was used to compare the three data sets for 2,523 sample plots (0.0327% of the population). The Land-Cover Characterization was slightly more closely associated with the USGS classification than was the USFS classification. The strongest associations for each Land-Cover Characterization class, in general, support the interpreted land-cover labels. A few Land-Cover Characterization classes with no, or only weak, associations with the interpreted class warrant further analysis. A comparison of the reference classifications identified potential sources of confusion. Techniques described in the remote-sensing literature for the analysis of contingency tables are designed to assess accuracy or agreement. The protocol and measures described in this dissertation provide a valuable set of tools for use by the resource scientist to efficiently and effectively handle the very large number of classes and relationships that exist in general global land-cover characterizations.

  11. 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.

  12. 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

  13. 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 (1σ 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.

  14. 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, (α,β)-2-deoxy-2-amino(ethylcarbamate)-D-glucose (ECB-DG) and (α,β)-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

  15. Reproducibility of the Structural Brain Connectome Derived from Diffusion Tensor Imaging

    PubMed Central

    Bonilha, Leonardo; Gleichgerrcht, Ezequiel; Fridriksson, Julius; Rorden, Chris; Breedlove, Jesse L.; Nesland, Travis; Paulus, Walter; Helms, Gunther; Focke, Niels K.

    2015-01-01

    Rationale Disruptions of brain anatomical connectivity are believed to play a central role in several neurological and psychiatric illnesses. The structural brain connectome is typically derived from diffusion tensor imaging (DTI), which may be influenced by methodological factors related to signal processing, MRI scanners and biophysical properties of neuroanatomical regions. In this study, we evaluated how these variables affect the reproducibility of the structural connectome. Methods Twenty healthy adults underwent 3 MRI scanning sessions (twice in the same MRI scanner and a third time in a different scanner unit) within a short period of time. The scanning sessions included similar T1 weighted and DTI sequences. Deterministic or probabilistic tractography was performed to assess link weight based on the number of fibers connecting gray matter regions of interest (ROI). Link weight and graph theory network measures were calculated and reproducibility was assessed through intra-class correlation coefficients, assuming each scanning session as a rater. Results Connectome reproducibility was higher with data from the same scanner. The probabilistic approach yielded larger reproducibility, while the individual variation in the number of tracked fibers from deterministic tractography was negatively associated with reproducibility. Links connecting larger and anatomically closer ROIs demonstrated higher reproducibility. In general, graph theory measures demonstrated high reproducibility across scanning sessions. Discussion Anatomical factors and tractography approaches can influence the reproducibility of the structural connectome and should be factored in the interpretation of future studies. Our results demonstrate that connectome mapping is a largely reproducible technique, particularly as it relates to the geometry of network architecture measured by graph theory methods. PMID:26332788

  16. The Kepler Input Catalog

    NASA Astrophysics Data System (ADS)

    Latham, D. W.; Brown, T. M.; Monet, D. G.; Everett, M.; Esquerdo, G. A.; Hergenrother, C. W.

    2005-12-01

    The Kepler mission will monitor 170,000 planet-search targets during the first year, and 100,000 after that. The Kepler Input Catalog (KIC) will be used to select optimum targets for the search for habitable earth-like transiting planets. The KIC will include all known catalogued stars in an area of about 177 square degrees centered at RA 19:22:40 and Dec +44:30 (l=76.3 and b=+13.5). 2MASS photometry will be supplemented with new ground-based photometry obtained in the SDSS g, r, i, and z bands plus a custom filter centered on the Mg b lines, using KeplerCam on the 48-inch telescope at the Whipple Observatory on Mount Hopkins, Arizona. The photometry will be used to estimate stellar characteristics for all stars brighter than K 14.5 mag. The KIC will include effective temperature, surface gravity, metallicity, reddening, distance, and radius estimates for these stars. The CCD images are pipeline processed to produce instrumental magnitudes at PSI. The photometry is then archived and transformed to the SDSS system at HAO, where the astrophysical analysis of the stellar characteristics is carried out. The results are then merged with catalogued data at the USNOFS to produce the KIC. High dispersion spectroscopy with Hectochelle on the MMT will be used to supplement the information for many of the most interesting targets. The KIC will be released before launch for use by the astronomical community and will be available for queries over the internet. Support from the Kepler mission is gratefully acknowledged.

  17. [F-18]-Fluoromisonidazole Quantification of Hypoxia in Human Cancer Patients using Image-derived Blood Surrogate Tissue Reference Regions

    PubMed Central

    Muzi, Mark; Peterson, Lanell M.; O’Sullivan, Janet N.; Fink, James R.; Rajendran, Joseph G.; McLaughlin, Lena J.; Muzi, John P.; Mankoff, David A.; Krohn, Kenneth A.

    2015-01-01

    18F-FMISO is the most widely used PET agent for imaging hypoxia, a condition associated with resistance to tumor therapy. 18F-FMISO equilibrates in normoxic tissues, but is retained under hypoxic conditions because of reduction and binding to macromolecules. A simple tissue-to-blood ratio (TB) is suitable for quantifying hypoxia. A threshold of TB ≥ 1.2 is useful in discriminating the hypoxic volume (HV) of tissue; TBmax is the maximum intensity of the hypoxic region and does not invoke a threshold. Because elimination of blood sampling would simplify clinical use, we tested the validity of using imaging regions as a surrogate for blood sampling. Methods Patients underwent 20 min 18F-FMISO scans during the 90–140 min interval post-injection with venous blood sampling. 223 18F-FMISO patient studies had detectable surrogate blood regions in the field-of-view. Quantitative parameters of hypoxia (TBmax, HV) derived from blood samples were compared to values using surrogate blood regions derived from heart, aorta and/or cerebellum. In a subset of brain cancer patients, parameters from blood samples and from cerebellum were compared for their ability to independently predict outcome. Results Vascular regions of heart showed the highest correlation to measured blood activity (R2 = 0.84). For brain studies, cerebellar activity was similarly correlated to blood samples. In brain cancer patients, Kaplan-Meier analysis showed that image-derived reference regions had nearly identical predictive power as parameters derived from blood, thus obviating the need for venous sampling in these patients. Conclusions Simple static analysis of 18F-FMISO PET captures both the intensity (TBmax) and spatial extent (HV) of tumor hypoxia. An image-derived region to assess blood activity can be used as a surrogate for blood sampling in quantification of hypoxia. PMID:26112020

  18. High input impedance amplifier

    NASA Technical Reports Server (NTRS)

    Kleinberg, Leonard L.

    1995-01-01

    High input impedance amplifiers are provided which reduce the input impedance solely to a capacitive reactance, or, in a somewhat more complex design, provide an extremely high essentially infinite, capacitive reactance. In one embodiment, where the input impedance is reduced in essence, to solely a capacitive reactance, an operational amplifier in a follower configuration is driven at its non-inverting input and a resistor with a predetermined magnitude is connected between the inverting and non-inverting inputs. A second embodiment eliminates the capacitance from the input by adding a second stage to the first embodiment. The second stage is a second operational amplifier in a non-inverting gain-stage configuration where the output of the first follower stage drives the non-inverting input of the second stage and the output of the second stage is fed back to the non-inverting input of the first stage through a capacitor of a predetermined magnitude. These amplifiers, while generally useful, are very useful as sensor buffer amplifiers that may eliminate significant sources of error.

  19. 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.

  20. Processing distributed inputs in coupled excitable lasers

    SciTech Connect

    Gonzalez, Cristina M.; Torrent, M. C.; Garcia-Ojalvo, Jordi; Buldu, Javier M.

    2007-11-15

    In many instances, networks of dynamical elements are subject to distributed input signals that enter the network through different nodes. In these cases, processing of the input signals may be mediated by coupling, in what constitutes an emerging property of the network. Here we study experimentally this effect in two mutually injected semiconductor lasers with optical feedback, operating in an excitable regime. The lasers are subject to different periodic input signals in their pump current, with distinct frequencies. Our results show that when the signals are harmonics of an absent fundamental, the laser array is able to process these signals and respond at the missing fundamental frequency. When the input frequencies are rigidly shifted from their harmonic values, the response frequency follows a simple law derived from a linear sum of the inputs, even though the array integrates the electrical inputs after having transduced them optically. The results are reproduced numerically with a dynamical model of the laser array.

  1. 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].

  2. A coumarin derivative as a fluorogenic glycoproteomic probe for biological imaging.

    PubMed

    Rong, Lei; Liu, Li-Han; Chen, Si; Cheng, Han; Chen, Chang-Sheng; Li, Ze-Yong; Qin, Si-Yong; Zhang, Xian-Zheng

    2014-01-21

    Fluorescence imaging in living cells is typically carried out using a functionalized fluorescent dye. But it often causes strong background noise under many conditions where washing is not applicable. Here, we report on a coumarin based fluorogenic probe, which can be used as a bioorthogonal-labeling tool for glycoproteins. The results indicated that the probe was able to image glycoproteins in living cells and it may also be suitable for intracellular imaging. PMID:24281692

  3. 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.

  4. 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

  5. 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

  6. Texture Descriptors Ensembles Enable Image-Based Classification of Maturation of Human Stem Cell-Derived Retinal Pigmented Epithelium

    PubMed Central

    Caetano dos Santos, Florentino Luciano; Skottman, Heli; Juuti-Uusitalo, Kati; Hyttinen, Jari

    2016-01-01

    Aims A fast, non-invasive and observer-independent method to analyze the homogeneity and maturity of human pluripotent stem cell (hPSC) derived retinal pigment epithelial (RPE) cells is warranted to assess the suitability of hPSC-RPE cells for implantation or in vitro use. The aim of this work was to develop and validate methods to create ensembles of state-of-the-art texture descriptors and to provide a robust classification tool to separate three different maturation stages of RPE cells by using phase contrast microscopy images. The same methods were also validated on a wide variety of biological image classification problems, such as histological or virus image classification. Methods For image classification we used different texture descriptors, descriptor ensembles and preprocessing techniques. Also, three new methods were tested. The first approach was an ensemble of preprocessing methods, to create an additional set of images. The second was the region-based approach, where saliency detection and wavelet decomposition divide each image in two different regions, from which features were extracted through different descriptors. The third method was an ensemble of Binarized Statistical Image Features, based on different sizes and thresholds. A Support Vector Machine (SVM) was trained for each descriptor histogram and the set of SVMs combined by sum rule. The accuracy of the computer vision tool was verified in classifying the hPSC-RPE cell maturation level. Dataset and Results The RPE dataset contains 1862 subwindows from 195 phase contrast images. The final descriptor ensemble outperformed the most recent stand-alone texture descriptors, obtaining, for the RPE dataset, an area under ROC curve (AUC) of 86.49% with the 10-fold cross validation and 91.98% with the leave-one-image-out protocol. The generality of the three proposed approaches was ascertained with 10 more biological image datasets, obtaining an average AUC greater than 97%. Conclusions Here we showed that the developed ensembles of texture descriptors are able to classify the RPE cell maturation stage. Moreover, we proved that preprocessing and region-based decomposition improves many descriptors’ accuracy in biological dataset classification. Finally, we built the first public dataset of stem cell-derived RPE cells, which is publicly available to the scientific community for classification studies. The proposed tool is available at https://www.dei.unipd.it/node/2357 and the RPE dataset at http://www.biomeditech.fi/data/RPE_dataset/. Both are available at https://figshare.com/s/d6fb591f1beb4f8efa6f. PMID:26895509

  7. COMETARY SCIENCE. 67P/Churyumov-Gerasimenko surface properties as derived from CIVA panoramic images.

    PubMed

    Bibring, J-P; Langevin, Y; Carter, J; Eng, P; Gondet, B; Jorda, L; Le Mouélic, S; Mottola, S; Pilorget, C; Poulet, F; Vincendon, M

    2015-07-31

    The structure and composition of cometary constituents, down to their microscopic scale, are critical witnesses of the processes and ingredients that drove the formation and evolution of planetary bodies toward their present diversity. On board Rosetta's lander Philae, the Comet Infrared and Visible Analyser (CIVA) experiment took a series of images to characterize the surface materials surrounding the lander on comet 67P/Churyumov-Gerasimenko. Images were collected twice: just after touchdown, and after Philae finally came to rest, where it acquired a full panorama. These images reveal a fractured surface with complex structure and a variety of grain scales and albedos, possibly constituting pristine cometary material. PMID:26228154

  8. 67P/Churyumov-Gerasimenko surface properties as derived from CIVA panoramic images

    NASA Astrophysics Data System (ADS)

    Bibring, J.-P.; Langevin, Y.; Carter, J.; Eng, P.; Gondet, B.; Jorda, L.; Le Mouélic, S.; Mottola, S.; Pilorget, C.; Poulet, F.; Vincendon, M.

    2015-07-01

    The structure and composition of cometary constituents, down to their microscopic scale, are critical witnesses of the processes and ingredients that drove the formation and evolution of planetary bodies toward their present diversity. On board Rosetta’s lander Philae, the Comet Infrared and Visible Analyser (CIVA) experiment took a series of images to characterize the surface materials surrounding the lander on comet 67P/Churyumov-Gerasimenko. Images were collected twice: just after touchdown, and after Philae finally came to rest, where it acquired a full panorama. These images reveal a fractured surface with complex structure and a variety of grain scales and albedos, possibly constituting pristine cometary material.

  9. Tailoring inputs to achieve maximal neuronal firing

    PubMed Central

    2011-01-01

    We consider the constrained optimization of excitatory synaptic input patterns to maximize spike generation in leaky integrate-and-fire (LIF) and theta model neurons. In the case of discrete input kicks with a fixed total magnitude, optimal input timings and strengths are identified for each model using phase plane arguments. In both cases, optimal features relate to finding an input level at which the drop in input between successive spikes is minimized. A bounded minimizing level always exists in the theta model and may or may not exist in the LIF model, depending on parameter tuning. We also provide analytical formulas to estimate the number of spikes resulting from a given input train. In a second case of continuous inputs of fixed total magnitude, we analyze the tuning of an input shape parameter to maximize the number of spikes occurring in a fixed time interval. Results are obtained using numerical solution of a variational boundary value problem that we derive, as well as analysis, for the theta model and using a combination of simulation and analysis for the LIF model. In particular, consistent with the discrete case, the number of spikes in the theta model rises and then falls again as the input becomes more tightly peaked. Under a similar variation in the LIF case, we numerically show that the number of spikes increases monotonically up to some bound and we analytically constrain the times at which spikes can occur and estimate the bound on the number of spikes fired. PMID:22656323

  10. Reproducibility of subregional trabecular bone micro-architectural measures derived from 7-Tesla magnetic resonance images.

    PubMed

    Chang, Gregory; Wang, Ligong; Liang, Guoyuan; Babb, James S; Saha, Punam K; Regatte, Ravinder R

    2011-06-01

    High-resolution magnetic resonance imaging (MRI) of trabecular bone combined with quantitative image analysis represents a powerful technique to gain insight into trabecular bone micro-architectural derangements in osteoporosis and osteoarthritis. The increased signal-to-noise ratio of ultra high-field MR (≥7 Tesla) permits images to be obtained with higher resolution and/or decreased scan time compared to scanning at 1.5/3T. In this small feasibility study, we show high measurement precision for subregional trabecular bone micro-architectural analysis performed on 7T knee MR images. The results provide further support for the use of trabecular bone measures as biomarkers in clinical studies of bone disorders. PMID:21221706

  11. 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.

  12. Texture analysis on parametric maps derived from dynamic contrast-enhanced magnetic resonance imaging in head and neck cancer

    PubMed Central

    Jansen, Jacobus FA; Lu, Yonggang; Gupta, Gaorav; Lee, Nancy Y; Stambuk, Hilda E; Mazaheri, Yousef; Deasy, Joseph O; Shukla-Dave, Amita

    2016-01-01

    AIM: To investigate the merits of texture analysis on parametric maps derived from pharmacokinetic modeling with dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) as imaging biomarkers for the prediction of treatment response in patients with head and neck squamous cell carcinoma (HNSCC). METHODS: In this retrospective study, 19 HNSCC patients underwent pre- and intra-treatment DCE-MRI scans at a 1.5T MRI scanner. All patients had chemo-radiation treatment. Pharmacokinetic modeling was performed on the acquired DCE-MRI images, generating maps of volume transfer rate (Ktrans) and volume fraction of the extravascular extracellular space (ve). Image texture analysis was then employed on maps of Ktrans and ve, generating two texture measures: Energy (E) and homogeneity. RESULTS: No significant changes were found for the mean and standard deviation for Ktrans and ve between pre- and intra-treatment (P > 0.09). Texture analysis revealed that the imaging biomarker E of ve was significantly higher in intra-treatment scans, relative to pretreatment scans (P < 0.04). CONCLUSION: Chemo-radiation treatment in HNSCC significantly reduces the heterogeneity of tumors. PMID:26834947

  13. 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.

  14. 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.

  15. Susceptibility of the wild-derived inbred CAST/Ei mouse to infection by orthopoxviruses analyzed by live bioluminescence imaging

    SciTech Connect

    Americo, Jeffrey L.; Sood, Cindy L.; Cotter, Catherine A.; Vogel, Jodi L.; Kristie, Thomas M.; Moss, Bernard Earl, Patricia L.

    2014-01-20

    Classical inbred mice are extensively used for virus research. However, we recently found that some wild-derived inbred mouse strains are more susceptible than classical strains to monkeypox virus. Experiments described here indicated that the 50% lethal dose of vaccinia virus (VACV) and cowpox virus (CPXV) were two logs lower in wild-derived inbred CAST/Ei mice than classical inbred BALB/c mice, whereas there was little difference in the susceptibility of the mouse strains to herpes simplex virus. Live bioluminescence imaging was used to follow spread of pathogenic and attenuated VACV strains and CPXV virus from nasal passages to organs in the chest and abdomen of CAST/Ei mice. Luminescence increased first in the head and then simultaneously in the chest and abdomen in a dose-dependent manner. The spreading kinetics was more rapid with VACV than CPXV although the peak photon flux was similar. These data suggest advantages of CAST/Ei mice for orthopoxvirus studies. - Highlights: • Wild-derived inbred CAST/Ei mice are susceptible to vaccinia virus and cowpox virus. • Morbidity and mortality from orthopoxviruses are greater in CAST/Ei than BALB/c mice. • Morbidity and mortality from herpes simplex virus type 1 are similar in both mice. • Imaging shows virus spread from nose to lungs, abdominal organs and brain. • Vaccinia virus spreads more rapidly than cowpox virus.

  16. Sulfonamide derivative targeting carbonic anhydrase IX as a nuclear imaging probe for colorectal cancer detection in vivo

    PubMed Central

    Guan, Siao-Syun; Cheng, Chun-Chia; Ho, Ai-Sheng; Wang, Chia-Chi; Luo, Tsai-Yueh; Liao, Tse-Zung; Chang, Jungshan; Wu, Cheng-Tien; Liu, Shing-Hwa

    2015-01-01

    Hypoxic microenvironment is a common situation in solid tumors. Carbonic anhydrase IX (CA9) is one of the reliable cellular biomarkers of hypoxia. The role of CA9 in colorectal cancer (CRC) remains to be clarified. CA9 inhibitor such as sulfonamides is known to block CA9 activation and reduce tumor growth consequently. Here, we aimed to investigate the CA9 expression in serum and tumor from different stages of CRC patients and utilize sulfonamide derivative with indium-111 labeling as a probe for CRC nuclear imaging detection in vivo. The serum CA9 was correlated with the tumor CA9 levels in different stages of CRC patients. Hypoxia increased cell viability and CA9 expression in colorectal cancer HCT-15 cells. Sulfonamide derivative 5-(2-aminoethyl)thiophene-2-sulfonamide (ATS) could bind with CA9 in vitro under hypoxia. Moreover, tumor tissues in HCT-15-induced xenograft mice possessed higher hypoxic fluorescence signal as compared with other organs. We also found that the radioisotope signal of indium-111 labeled ATS, which was utilized for CRC detection in HCT-15-induced xenograft mice, was markedly enhanced in tumors as compared with non-ATS control. Taken together, these findings suggest that CA9 is a potential hypoxic CRC biomarker and measurement of serum CA9 can be as a potential tool for diagnosing CA9 expressions in CRC clinical practice. The radioisotope-labeled sulfonamide derivative (ATS) may be useful to apply in CRC patients for nuclear medicine imaging. PMID:26447758

  17. Direct imaging of biological sulfur dioxide derivatives in vivo using a two-photon phosphorescent probe.

    PubMed

    Li, Guanying; Chen, Yu; Wang, Jinquan; Wu, Jingheng; Gasser, Gilles; Ji, Liangnian; Chao, Hui

    2015-09-01

    Sulfur dioxide (SO2) and its derivatives sulfite and bisulfite play important roles in biological systems. However, in vivo detection of sulfite/bisulfite remains challenging. In this study, we developed a dinuclear Ir(III) complex (Ir4) as a two-photon phosphorescent probe for sulfite and bisulfite. Ir4 selectively and rapidly responded, with high sensitivity, to sulfite/bisulfite over other bio-related ions and molecules. One-photon and two-photon microscopy images revealed that Ir4 preferentially targeted mitochondria and was capable of imaging biological sulfite/bisulfite levels in vitro and in vivo. In situ sulfite generation in Caenorhabditis elegans was visualized by two-photon excitation real-time imaging. Finally, Ir4 was employed to monitor sulfite distribution in rat brain and other tissues. This study is the first report of the direct visualization of SO2 derivatives in vivo. These results provide new insights into the biological importance of SO2. PMID:26100342

  18. Accurate photometric light curves of the lensed components of Q2237+0305 derived with an optimal image subtraction technique: Evidence for microlensing in image A

    NASA Astrophysics Data System (ADS)

    Moreau, O.; Libbrecht, C.; Lee, D.-W.; Surdej, J.

    2005-06-01

    Using an optimal image subtraction technique, we have derived the V and R light curves of the four lensed QSO components of Q2237+0305 from the monitoring CCD frames obtained by the GLITP collaboration with the 2.6 m NOT telescope in 1999/2000 (Alcalde et al. 2002). We give here a detailed account of the data reduction and analysis and of the error estimates. In agreement with Wo?niak et al. (2000a,b), the good derived photometric accuracy of the GLITP data allows to discuss the possible interpretation of the light curve of component A as due to a microlensing event taking place in the deflecting galaxy. This interpretation is strengthened by the colour dependence of the early rise of the light curve of component A, as it probably corresponds to a caustics crossing by the QSO source.

  19. 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.

  20. Sparse regularization for EIT reconstruction incorporating structural information derived from medical imaging.

    PubMed

    Gong, Bo; Schullcke, Benjamin; Krueger-Ziolek, Sabine; Mueller-Lisse, Ullrich; Moeller, Knut

    2016-06-01

    Electrical impedance tomography (EIT) reconstructs the conductivity distribution of a domain using electrical data on its boundary. This is an ill-posed inverse problem usually solved on a finite element mesh. For this article, a special regularization method incorporating structural information of the targeted domain is proposed and evaluated. Structural information was obtained either from computed tomography images or from preliminary EIT reconstructions by a modified k-means clustering. The proposed regularization method integrates this structural information into the reconstruction as a soft constraint preferring sparsity in group level. A first evaluation with Monte Carlo simulations indicated that the proposed solver is more robust to noise and the resulting images show fewer artifacts. This finding is supported by real data analysis. The structure based regularization has the potential to balance structural a priori information with data driven reconstruction. It is robust to noise, reduces artifacts and produces images that reflect anatomy and are thus easier to interpret for physicians. PMID:27203627

  1. Fluorescent Tobacco mosaic virus-Derived Bio-Nanoparticles for Intravital Two-Photon Imaging

    PubMed Central

    Niehl, Annette; Appaix, Florence; Boscá, Sonia; van der Sanden, Boudewijn; Nicoud, Jean-François; Bolze, Frédéric; Heinlein, Manfred

    2016-01-01

    Multi-photon intravital imaging has become a powerful tool to investigate the healthy and diseased brain vasculature in living animals. Although agents for multi-photon fluorescence microscopy of the microvasculature are available, issues related to stability, bioavailability, toxicity, cost or chemical adaptability remain to be solved. In particular, there is a need for highly fluorescent dyes linked to particles that do not cross the blood brain barrier (BBB) in brain diseases like tumor or stroke to estimate the functional blood supply. Plant virus particles possess a number of distinct advantages over other particles, the most important being the multi-valency of chemically addressable sites on the particle surface. This multi-valency, together with biological compatibility and inert nature, makes plant viruses ideal carriers for in vivo imaging agents. Here, we show that the well-known Tobacco mosaic virus is a suitable nanocarrier for two-photon dyes and for intravital imaging of the mouse brain vasculature. PMID:26793221

  2. Fluorescent Tobacco mosaic virus-Derived Bio-Nanoparticles for Intravital Two-Photon Imaging.

    PubMed

    Niehl, Annette; Appaix, Florence; Boscá, Sonia; van der Sanden, Boudewijn; Nicoud, Jean-François; Bolze, Frédéric; Heinlein, Manfred

    2015-01-01

    Multi-photon intravital imaging has become a powerful tool to investigate the healthy and diseased brain vasculature in living animals. Although agents for multi-photon fluorescence microscopy of the microvasculature are available, issues related to stability, bioavailability, toxicity, cost or chemical adaptability remain to be solved. In particular, there is a need for highly fluorescent dyes linked to particles that do not cross the blood brain barrier (BBB) in brain diseases like tumor or stroke to estimate the functional blood supply. Plant virus particles possess a number of distinct advantages over other particles, the most important being the multi-valency of chemically addressable sites on the particle surface. This multi-valency, together with biological compatibility and inert nature, makes plant viruses ideal carriers for in vivo imaging agents. Here, we show that the well-known Tobacco mosaic virus is a suitable nanocarrier for two-photon dyes and for intravital imaging of the mouse brain vasculature. PMID:26793221

  3. Cirrus cloud characteristics derived from volume imaging lidar, high spectral resolution lidar, HIS radiometer, and satellite

    NASA Technical Reports Server (NTRS)

    Grund, Christian J.; Ackerman, Steven A.; Eloranta, Edwin W.; Knutsen, Robert O.; Revercomb, Henry E.; Smith, William L.; Wylie, Donald P.

    1990-01-01

    Preliminary measurement results are presented from the Cirrus Remote Sensing Pilot Experiment which used a unique suite of instruments to simultaneously retrieve cirrus cloud visible and IR optical properties, while addressing the disparities between satellite volume averages and local point measurements. The experiment employed a ground-based high resolution interferometer sounder (HIS) and a second Fourier transform spectrometer to measure the spectral radiance in the 4-20 micron band, a correlated high spectral resolution lidar, a volume imaging lidar, a CLASS radiosonde system, the Scripps Whole Sky Imager, and multispectral VAS, HIRS, and AVHRR satellite data from polar orbiting and geostationary satellites. Data acquired during the month long experiment included continuous daytime monitoring with the Whole Sky Imager.

  4. On the camparability of cloud fractions derived from whole sky imager and ceilometer data

    SciTech Connect

    Rodriguez, D.

    1998-01-30

    The Atmospheric Radiation Measurement (ARM) Program`s most heavily instrumented site is its central facility in Lamont, OK. With respect to cloud observations, the instrumentation included a whole sky imager, ceilometers, lidar, millimeter cloud radar, microwave profilers, and radiosondes. Data from three of these instrument--the Whole Sky Imager (WSI), Belfort Laser Ceilometer (BLC) and Micropulse Lidar (MPL)-- are used in this study primarily to investigate the utility of using ceilometers, now strategically emplaced at four additional locations along the perimeter of the site.

  5. Differential input preamplifier

    NASA Technical Reports Server (NTRS)

    Callaway, P. W.

    1972-01-01

    Preamplifier chops and amplifies very low level output of thermopile infrared detectors that will be used to measure thermal energy flux of Jupiter and its departure from a blackbody spectrum. Output signal has negligible phase shift. AC signal is RC-coupled to input stage of other amplifiers.

  6. Efficient nano iron particle-labeling and noninvasive MR imaging of mouse bone marrow-derived endothelial progenitor cells

    PubMed Central

    Chen, Rong; Yu, Hui; Jia, Zhen-Yu; Yao, Qun-Li; Teng, Gao-Jun

    2011-01-01

    In this study, we sought to label mouse bone marrow-derived endothelial progenitor cells (EPCs) with Resovist® in vitro and to image them using 7.0 Tesla (T) magnetic resonance imaging (MRI). Mouse bone marrow-derived EPCs were cultured in endothelial basal medium with endothelial growth supplement. They were then characterized by immunocytochemistry, flow cytometry, and fluorescence quantitative polymerase chain reaction. Their functions were evaluated by measuring their uptake of 1,1-dioctadecyl-3,3,3,3-tetramethylindocarbocyanine-labeled acetylated low-density lipoprotein (Dil-Ac-LDL), binding of fluorine isothiocyanate (FITC)-labeled Ulex europaeus agglutinin (UEA), and formation of capillary-like networks. EPCs were labeled with superparamagnetic iron oxide (SPIO) and their proliferation was then assessed in a water-soluble tetrazolium (WST-8)-based cell proliferation assay. Spin echo sequence (multislice, multiecho [MSME]) and gradient echo sequence (2D-FLASH) were used to detect differences in the numbers of labeled cells by 7.0 T MRI. The results showed that the cultured cells were of “cobblestone”-like shape and positive for CD133, CD34, CD31, von Willebrand factor, kinase domain receptor, and CD45, but negative for F4/80. They could take up Dil-Ac-LDL, bind FITC-UEA, and form capillary-like networks on Matrigel in vitro. Prussian-blue staining demonstrated that the cells were efficiently labeled with SPIO. The single-cell T2* effect was more obvious in the 2D-FLASH sequence than in the MSME sequence. Further, there were almost no adverse effects on cell vitality and proliferation. In conclusion, mouse bone marrow-derived EPCs can be efficiently labeled with SPIO and imaged with 7.0-T MRI. They may thus be traced by MRI following transplantation for blood vessel disorders and cancer treatment. PMID:21468354

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

    SciTech Connect

    Tun, Samuel D.; Vourlidas, A.

    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.

  8. Deriving statistical significance maps for support vector regression using medical imaging data

    PubMed Central

    Gaonkar, Bilwaj; Sotiras, Aristeidis; Davatzikos, Christos

    2013-01-01

    Regression analysis involves predicting a continuous variable using imaging data. The Support Vector Regression (SVR) algorithm has previously been used in addressing regression analysis in neuroimaging. However, identifying the regions of the image that the SVR uses to model the dependence of a target variable remains an open problem. It is an important issue when one wants to biologically interpret the meaning of a pattern that predicts the variable(s) of interest, and therefore to understand normal or pathological process. One possible approach to the identification of these regions is the use of permutation testing. Permutation testing involves 1) generation of a large set of ‘null SVR models’ using randomly permuted sets of target variables, and 2) comparison of the SVR model trained using the original labels to the set of null models. These permutation tests often require prohibitively long computational time. Recent work in support vector classification shows that it is possible to analytically approximate the results of permutation testing in medical image analysis. We propose an analogous approach to approximate permutation testing based analysis for support vector regression with medical imaging data. In this paper we present 1) the theory behind our approximation, and 2) experimental results using two real datasets. PMID:25328907

  9. Differential behaviour of cationic triphenylamine derivatives in fixed and living cells: triggering and imaging cell death.

    PubMed

    Chennoufi, R; Bougherara, H; Gagey-Eilstein, N; Dumat, B; Henry, E; Subra, F; Mahuteau-Betzer, F; Tauc, P; Teulade-Fichou, M-P; Deprez, E

    2015-10-14

    Triphenylamines are on/off fluorescent DNA minor groove binders, allowing nuclear staining of fixed cells. By contrast, they accumulate in the cytoplasm of living cells and efficiently trigger cell apoptosis upon prolonged visible light irradiation. This process occurs concomitantly with their subcellular re-localization to the nucleus, enabling fluorescence imaging of apoptosis. PMID:26303028

  10. 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

  11. Picture-based physics: Using POD derived process constraints to enhance imaging of groundwater systems

    NASA Astrophysics Data System (ADS)

    Moysey, S. M.; Oware, E. K.; Khan, T.

    2012-12-01

    Geophysical imaging techniques are increasingly important tools for developing conceptual models of subsurface processes and characterizing hydrogeologic properties. In particular, recent studies have shown that coupled inversion, i.e., using coupled hydrologic process and geophysical instrument simulators as a single forward model, can lead to vast improvements in our ability to accurately constrain estimates of aquifer hydraulic properties with a limited amount of geophysical data. In this case, the hydrologic model acts as an implicit process constraint that regularizes the inverse problem. A major challenge with the coupled approach, however, is that the hydrologic process model is a hard constraint on the inverse problem; it is not possible to accurately reproduce subsurface behaviors when the conceptualization of the hydrologic model is incorrect. To overcome this issue, we take an image-processing perspective to develop physics-based constraints for inverse problems. Philosophically our approach is analogous to the use of images as training data for inferring multiple point geostatistics. In our case, however, we instead use training images to extract a set of basis vectors using proper orthogonal decomposition (POD) that can be used to constrain the inverse problem. Careful selection of a basis for an inverse problem is important as an appropriate basis can significantly improve estimation efficiency and accuracy. A key element of our approach is that the training images are generated using Monte Carlo simulations of the physical groundwater process of interest (e.g., flow and transport). As a result the training images and POD basis provide a site specific, non-parametric representation of the processes driving the groundwater system. A consequence is that a limited number of POD basis vectors can be used to compactly capture complex heterogeneities within the subsurface, thereby reducing the dimensionality of parameter space and effectively regularizing the inverse problem. In this talk we provide a conceptual understanding of POD and its application to inverse problems. We then provide examples where the POD inversion strategy is used to enhance geophysical imaging of unsaturated flow in the vadose zone and solute transport in an aquifer. Finally, we discuss how the POD approach can be extended for applications such as hydraulic tomography and general geostatistical estimation problems.

  12. Scanning Tunneling Imaging of Bio-Organic Molecules and Their Tunneling Properties: Fatty Acids, Their Derivatives and Cholesteryl Stearate

    NASA Astrophysics Data System (ADS)

    Yoshimura, Kousei; Arakawa, Hideo; Ikai, Atsushi

    1995-06-01

    Scanning tunneling microscopy imaging was applied to long-chain fatty acids, their derivatives and cholesteryl stearate in the adsorbed state at the liquid-solid interface between phenyloctane and highly oriented pyrolytic graphite. Cerotic acid, lignoceric acid, stearic acid, sodium stearate, stearoyl amide, and stearoyl anilide all produced regular arrays of dark and bright bands. Bright bands in the images of all execept the last compound were assigned as side-by-side alignment of hydrocarbon chains based on the variation of the band width between the three fatty acids. In the case of stearoyl anilide, the bright part was assigned to aromatic ring structure and the wider dark area to the hydrocarbon part.

  13. 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

  14. Homologous RBC-derived vesicles as ultrasmall carriers of iron oxide for magnetic resonance imaging of stem cells

    NASA Astrophysics Data System (ADS)

    Chang, Microsugar; Hsiao, Jong-Kai; Yao, Ming; Chien, Li-Ying; Hsu, Szu-Chun; Ko, Bor-Sheng; Chen, Shin-Tai; Liu, Hon-Man; Chen, Yao-Chang; Yang, Chung-Shi; Huang, Dong-Ming

    2010-06-01

    Ultrasmall superparamagnetic iron oxide (USPIO) particles are very useful for cellular magnetic resonance imaging (MRI), which plays a key role in developing successful stem cell therapies. However, their low intracellular labeling efficiency, and biosafety concerns associated with their use, have limited their potential usage. In this study we develop a novel system composed of RBC-derived vesicles (RDVs) for efficient delivery of USPIO particles into human bone marrow mesenchymal stem cells (MSCs) for cellular MRI in vitro and in vivo. RDVs are highly biosafe to their autologous MSCs as manifested by cell viability, differentiation, and gene microarray assays. The data demonstrate the potential of RDVs as intracellular delivery vehicles for biomedical applications.

  15. [18F-Berberine Derivatives: a Potential Molecular Imaging Agent for Tumor Targeting by PET/CT Tumor].

    PubMed

    Mei, Xiaoli; Wu, Xiaoai; Zhang, Tong; Liang, Meng; Fan, Chengzhong

    2015-04-01

    Cancer is one of the main causes of death for human beings. Clinical oncologists increasingly rely upon imaging for diagnosis, stage, response assessment, and follow-up in cancer patient. However, 18F-FDG is not a tumor specific agent, inflammation and infection also have intensive uptake of 18F-FDG, resulting in false positive diagnosis, and some tumors have low uptake of 18F-FDG or even do not uptake 18F-FDG, leading to false negative diagnosis. So it is urgent to develop non-18F-FDG novel tumor targeting agent. Recently, a large number of researches in vitro have demonstrated that berberine has anti-tumor activity against a variety of tumor cells by inducing tumor cell apoptosis through inhibition of mitochondrial respiratory chain etc. So far, there is no credible evidence of berberine targeting in tumor in vivo. We proposed a hypothesis that berberine has the characteristics of tumor targeting biodistribution in vivo, and verified the proposal by 18F-berberine PET/CT imaging in VX2 muscle tumor-bearing rabbit model. In this review, we intend to give an overview of the progress of berberine anticancer, the structural bases of berberine anticancer and the uderlying molecular mechanisms of berberine anticancer indentified so far. We also introduce the first visualization of 18F labeled berberine derivatives targeting tumor in VX2 muscle tumor-bearing rabbit model by PET/CT. These breakthrough findings suggest that 18F-berberine derivatives as a potential PET/CT tumor targeted molecular imaging agent may have important implications for cancer targeting therapy, molecular imaging and modernization of Traditional Chinese Medicine. PMID:26211272

  16. 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.

  17. High-resolution Vesta Low Altitude Mapping Orbit Atlas derived from Dawn Framing Camera images

    NASA Astrophysics Data System (ADS)

    Roatsch, Th.; Kersten, E.; Matz, K.-D.; Preusker, F.; Scholten, F.; Elgner, S.; Jaumann, R.; Raymond, C. A.; Russell, C. T.

    2013-09-01

    The Dawn Framing Camera (FC) acquired close to 10,000 clear filter images of Vesta with a resolution of about 20 m/pixel during the Low Altitude Mapping Orbit (LAMO) between December 2011 and April 2012. We ortho-rectified these images and produced a global high-resolution uncontrolled mosaic of Vesta. This global mosaic is the baseline for a high-resolution Vesta atlas that consists of 30 tiles mapped at a scale between 1:200,000 and 1:225,180. The nomenclature used in this atlas was proposed by the Dawn team and was approved by the International Astronomical Union (IAU). The whole atlas is available to the public through the Dawn GIS web page [http://dawn_gis.dlr.de/atlas].

  18. Electrical resistivity image of the South Atlantic continental margin derived from onshore and offshore magnetotelluric data

    NASA Astrophysics Data System (ADS)

    Kapinos, G.; Weckmann, U.; Jegen-Kulcsar, M.; Meqbel, N.; Neska, A.; Katjiuongua, T. T.; Hoelz, S.; Ritter, O.

    2016-01-01

    We present a deep electrical resistivity image from the passive continental margin in Namibia. The approximately 700 km long magnetotelluric profile follows the Walvis Ridge offshore, continues onshore across the Kaoko Mobile Belt and reaches onto the Congo Craton. Two-dimensional inversion reveals moderately resistive material offshore, atypically low for oceanic lithosphere, reaching depths of 15-20 km. Such moderate resistivities are consistent with seismic P wave velocity models, which suggest up to 35 km thick crust. The Neoproterozoic rocks of the Kaoko Mobile Belt are resistive, but NNW-striking major shear-zones are imaged as subvertical, conductive structures in the upper and middle crust. Since the geophysical imprint of the shear zones is intact, opening of the South Atlantic in the Cretaceous did not alter the middle crust. The transition into the cratonic region coincides with a deepening of the high-resistive material to depths of more than 60 km.

  19. A pyrene derivative for Hg(2+) -selective fluorescent sensing and its application in in vivo imaging.

    PubMed

    Wang, Guang Ke; Mi, Qi Li; Zhao, Li Yun; Hu, Jun Jie; Guo, Lin E; Zou, Xiao Ju; Liu, Bo; Xie, Xiao Guang; Zhang, Jun Feng; Zhao, Qi Hua; Zhou, Ying

    2014-03-01

    An Hg(2+) -selective fluorescent sensor (1) bearing pyrene as a fluorophore was synthesized. A sandwich-stacking binding mode was formed during the binding process, which increased the excimer fluorescence 22-fold at 490 nm. Compound 1 was successfully applied in in vivo imaging to trace the enrichment and distribution of mercury in the nervous system, digestive system, and reproductive system of Caenorhabditis elegans, as well as the organs of zebrafish. PMID:24323430

  20. Visualizing 2D Probability Distributions from Satellite Image-Derived Data

    NASA Technical Reports Server (NTRS)

    Kao, David; Dungan, Jennifer; Pang, Alex; Biegel, Bryan (Technical Monitor)

    2002-01-01

    Creating maps of biophysical and geophysical variables using Earth Observing System (EOS) satellite image data is an important component of Earth science. These 2D maps have a single value at every location and standard techniques are used to visualize them. Current tools fall short, however, when it is necessary to describe a distribution of values at each location. Distributions may represent a frequency of occurrence over time, frequency of occurrence from multiple runs of an ensemble forecast or possible values from an uncertainty model. 'Distribution data sets' are described, then a case study is presented to visualize such 2D distributions. Distribution data sets are different from multivariate data sets in the sense that the values are for a single variable instead of multiple variables. Our case study data consists of multiple realizations of percent forest cover, generated using a geostatistical technique that combines ground measurements and satellite imagery to model uncertainty about forest cover. We present several approaches for analyzing and visualizing such data sets. The first is a pixel-wise analysis of the probability density functions for the 2D image while the second is an analysis of features identified within the image. Such pixel-wise and feature-wise views will give Earth scientists a more complete understanding of distribution data sets.

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

    PubMed Central

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

    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 of experience with microcirculatory OPS imaging, premeditated qualifications for a simple, translucent and reproducible way of flow scoring were defined. Consecutively, a single-centre prospective observational validation study was performed in a group of 12 patients with an abdominal sepsis and a new stoma. Flow images of the microcirculation in vascular beds of the sublingual and stoma region were obtained, processed and analysed in a standardised way. We validated intra-observer and inter-observer reproducibility with kappa cross-tables for both types of microvascular beds. Results Agreement and kappa coefficients were >85% and >0.75, respectively, for interrater and intrarater variability in quantification of flow abnormalities during sepsis, in different subsets of microvascular architecture. Conclusion Semi-quantitative analysis of microcirculatory flow, as described, provides a reproducible and transparent tool in clinical research to monitor and evaluate the microcirculation during sepsis. PMID:16280059

  2. High-resolution Ceres Survey ATLAS derived from Dawn FC images

    NASA Astrophysics Data System (ADS)

    Roatsch, T.; Kersten, E.; Matz, K.-D.; Preusker, F.; Scholten, F.; Jaumann, R.; Raymond, C. A.; Russell, C. T.

    2015-10-01

    NASA's Dawn spacecraft will orbit the dwarf planet Ceres in June 2015 with an altitude of about 4,400 km to characterize the geology, elemental and mineralogical composition, topography, shape, and internal structure of Ceres before it will be transferred to lower orbits. One of the major goals of the mission is a global mapping of Ceres. Data: The Dawn mission will map Ceres from three different orbital heights during Survey orbit (4,424 km altitude), HAMO (High Altitude Mapping Orbit, 1474 km altitude), and LAMO (Low Altitude Mapping Orbit, 374 km altitude) [1]. The Dawn mission is equipped with a framing camera (FC) [2]. Dawn will orbited Ceres during Survey in 7 cycles in June 2015. The framing camera will take about 700 clear filter images with a resolution of about 400 m/pixel during these cycles. The images will be taken with different viewing angles and different illumination conditions. We will select the nadir looking images with similar illumination conditions for the global mosaic of Ceres.

  3. Seismic Velocities Imaging around "AFA" Hydrothermal Area in West Java, Indonesia derived from Dense Seimometer Network

    NASA Astrophysics Data System (ADS)

    Fanani Akbar, Akhmad; Nugraha, Andri Dian; Jousset, Philippe GM; Ryannugroho, Riskiray; Gassner, Alexandra; Jaya, Makky S.; Sule, Rachmat; Diningrat, Wahyuddin; Hendryana, Andri; Kusnadi, Yosep; Umar, Muksin; Indrinanto, Yudi; Erbas, Kemal

    2015-04-01

    We have deployed about 48 three component seismometers around "AFA" hydrothermal are in West Java, Indonesia from October 2012 up to October 2014 in order to detect microseismic event and to enhance our knowledge about subsurface seismic stucture. The seismometer network in this study, is the first dense seismometer array monitoring around hydrothermal area in Indonesia so far. We analyzed a huge waveform data set to distinguish microseismic, local and regional events. Then, we picked the onset of P-and S-wave arrival of microseismic events carefully visually by eye. We determined the initial microseismic event by applying Geiger's method with uniform seismic velocity model. Totally, we have been successfully determined 2,497 microseismic events around this hydrothermal area. We also improved 1D seismic velocities (Vp, Vs) and simultaneously with hypocenter adjustment as input for the tomography inversion in this study. Overall, the microseismic events are concentrated around production area activities and we also found strong cluster microseismic event in Southern part of this region which still need to be investigated in more details. Now, we are going on tomographic inversion step by using double-difference method. We are going to show more information during the meeting.

  4. Cellular Bioenergetics is an Important Determinant of the Molecular Imaging Signal Derived from Luciferase and the Sodium-Iodide Symporter

    PubMed Central

    Chang, Connie; Chan, Angel; Lin, Xiaoping; Higuchi, Takahiro; Terrovitis, John; Afzal, Junaid M.; Rittenbach, Andrew; Sun, Dongdong; Vakrou, Styliani; Woldemichael, Kirubel; O’Rourke, Brian; Wahl, Richard; Pomper, Martin; Tsui, Benjamin; Abraham, M. Roselle

    2013-01-01

    Rationale Molecular imaging is useful for longitudinal assessment of engraftment. However, it is not known which factors, other than cell number can influence the molecular imaging signal obtained from reporter genes. Objective The effects of cell dissociation/suspension on cellular bioenergetics and the signal obtained by firefly luciferase(fluc) and human Na-I symporter(hNIS) labeling of cardiosphere-derived cells (CDCs) was investigated. Methods and Results 18FDG uptake, ATP levels, 99mTc-pertechnetate uptake and bioluminescence were measured in vitro, in adherent and suspended CDCs. In vivo dual isotope SPECT-CT imaging or bioluminescence imaging (BLI) were performed 1hr and 24hrs following CDC transplantation. SPECT quantification was performed using a phantom for signal calibration. Cell loss between 1hr & 24hrs post-transplantation was quantified by qPCR and ex vivo luciferase assay. Cell dissociation followed by suspension for 1hr resulted in decreased glucose uptake, cellular ATP, 99mTc uptake and BLI signal by 82%, 43%, 42%, and 44% respectively, when compared to adherent cells, in vitro. In vivo 99mTc uptake was significantly lower at 1hr, when compared to 24hrs following cell transplantation in the non-infarct (p<0.001, n=3) and infarct (p<0.001, n =4) model, despite significant cell loss during this period. The in vivo BLI signal was significantly higher at 1hr than at 24hrs (p<0.01), with the BLI signal being higher when CDCs were suspended in glucose-containing medium compared to saline(PBS). Conclusion Adhesion is an important determinant of cellular bioenergetics, 99mTc-pertechnetate uptake and BLI signal. BLI and NIS imaging may be useful for in vivo optimization of bioenergetics in transplanted cells. PMID:23255420

  5. Sol-gel-derived ferroelectric films as pyroelectric detectors in imaging applications

    NASA Astrophysics Data System (ADS)

    Teowee, Gimtong T.; McCarthy, K.; Uhlmann, Donald R.

    1996-06-01

    This paper reviews the latest developments in pyroelectric devices for IR detection based on sol-gel derived ferroelectric thin films, highlighted by recent results from our laboratories. The optimization of sol-gel processing has led to ferroelectric films with pyroelectric coefficients as high as 200 nC/cm2-K. Some modeling results of the thin film devices, which aid in device design, are also discussed. At the film level, various factors such as chemistries, microstructures and processing conditions all affect the final pyroelectric properties of the films. At the device level, processing compatibility and device layout need to be taken into account to optimize fully the device performance.

  6. 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.

  7. Quantitative Live Imaging of Human Embryonic Stem Cell Derived Neural Rosettes Reveals Structure-Function Dynamics Coupled to Cortical Development

    PubMed Central

    Mutukula, Naresh; Edri, Reuven; Elkabetz, Yechiel

    2015-01-01

    Neural stem cells (NSCs) are progenitor cells for brain development, where cellular spatial composition (cytoarchitecture) and dynamics are hypothesized to be linked to critical NSC capabilities. However, understanding cytoarchitectural dynamics of this process has been limited by the difficulty to quantitatively image brain development in vivo. Here, we study NSC dynamics within Neural Rosettes—highly organized multicellular structures derived from human pluripotent stem cells. Neural rosettes contain NSCs with strong epithelial polarity and are expected to perform apical-basal interkinetic nuclear migration (INM)—a hallmark of cortical radial glial cell development. We developed a quantitative live imaging framework to characterize INM dynamics within rosettes. We first show that the tendency of cells to follow the INM orientation—a phenomenon we referred to as radial organization, is associated with rosette size, presumably via mechanical constraints of the confining structure. Second, early forming rosettes, which are abundant with founder NSCs and correspond to the early proliferative developing cortex, show fast motions and enhanced radial organization. In contrast, later derived rosettes, which are characterized by reduced NSC capacity and elevated numbers of differentiated neurons, and thus correspond to neurogenesis mode in the developing cortex, exhibit slower motions and decreased radial organization. Third, later derived rosettes are characterized by temporal instability in INM measures, in agreement with progressive loss in rosette integrity at later developmental stages. Finally, molecular perturbations of INM by inhibition of ACTIN or NON-MUSCLE MYOSIN-II (NMII) reduced INM measures. Our framework enables quantification of cytoarchitecture NSC dynamics and may have implications in functional molecular studies, drug screening, and iPS cell-based platforms for disease modeling. PMID:26473351

  8. Stress orientation on the Norwegian continental shelf derived from borehole failures observed in high-resolution borehole imaging logs

    NASA Astrophysics Data System (ADS)

    Brudy, Martin; Kjrholt, Halvor

    2001-07-01

    Knowledge of stress orientation is crucial for the understanding of many processes in the earth's crust such as tectonic development, earthquake occurrence, and fluid transport along faults. In the case of the Norwegian continental shelf, which is a prolific area for hydrocarbon production, this knowledge also plays an important role for engineering decisions with respect to wellbore stability and reservoir management. Therefore, data on stress orientation have been collected extensively over the past few years in this region. However, nearly all data published for the Norwegian continental shelf for depths less than 6 km are based on the evaluation of four-arm caliper data, a method with intrinsic limitations. For greater depths stress orientation is derived from earthquake focal plane mechanisms. This article presents stress orientation data derived from an extensive set of image logs throughout the Norwegian continental shelf. The analysis is based on the identification of compressive and tensile failures of the borehole wall in electrical and acoustic borehole imaging logs. This method for the determination of the stress orientation is found to be highly reliable and capable of delivering detailed and accurate results, and thus is far superior to the analysis of breakouts from four-arm caliper logs. The analysis of image logs shows that the stress orientation is consistent both regionally and with depth. Strong variations in stress orientation, which are often interpreted from earlier analyses of four-arm caliper data, are not observed. This may indicate that some of the earlier four-arm caliper analyses may have been biased by the misinterpretation of drilling-induced artefacts as stress-induced breakouts. Stress-induced failures of the borehole wall are observed in only about 40% of the wells analysed in this paper. This does not support the conclusion that the horizontal stresses are isotropic. It just indicates that the stress difference in combination with the borehole conditions (downhole pressure and temperature) was insufficient to induce these failures.

  9. Effect of chirality on cellular uptake, imaging and photodynamic therapy of photosensitizers derived from chlorophyll-a.

    PubMed

    Srivatsan, Avinash; Pera, Paula; Joshi, Penny; Wang, Yanfang; Missert, Joseph R; Tracy, Erin C; Tabaczynski, Walter A; Yao, Rutao; Sajjad, Munawwar; Baumann, Heinz; Pandey, Ravindra K

    2015-07-01

    We have previously shown that the (124)I-analog of methyl 3-(1'-m-iodobenzyloxy) ethyl-3-devinyl-pyropheophorbide-a derived as racemic mixture from chlorophyll-a can be used for PET (positron emission tomography)-imaging in animal tumor models. On the other hand, as a non-radioactive analog, it showed excellent fluorescence and photodynamic therapy (PDT) efficacy. Thus, a single agent in a mixture of radioactive ((124)I-) and non-radioactive ((127)I) material can be used for both dual-imaging and PDT of cancer. Before advancing to Phase I human clinical trials, we evaluated the activity of the individual isomers as well as the impact of a chiral center at position-3(1) in directing in vitro/in vivo cellular uptake, intracellular localization, epithelial tumor cell-specific retention, fluorescence/PET imaging, and photosensitizing ability. The results indicate that both isomers (racemates), either as methyl ester or carboxylic acid, were equally effective. However, the methyl ester analogs, due to subcellular deposition into vesicular structures, were preferentially retained. All derivatives containing carboxylic acid at the position-17(2) were noted to be substrate for the ABCG2 (a member of the ATP binding cassette transporters) protein explaining their low retention in lung tumor cells expressing this transporter. The compounds in which the chirality at position-3 has been substituted by a non-chiral functionality showed reduced cellular uptake, retention and lower PDT efficacy in mice bearing murine Colon26 tumors. PMID:25936263

  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 encapsulated [111In]-Labeled Liposome showed major uptake in RES in both PET and SPECT images. ROI analysis of SPECT image enabled by 111In corresponded with PET image enabled by 18F demonstrating the feasibility of dual tracer imaging from the single nanoconstruct. Future work involves the intensive in vitro characterization of [18F]-FCP encapsulated [ 111In]-Labeled Liposome and detailed in vivo evaluation of [ 18F]-FCP encapsulated [111In]-Labeled Liposome in various tumor models.

  11. Statistical storm time examination of MLT-dependent plasmapause location derived from IMAGE EUV

    NASA Astrophysics Data System (ADS)

    Katus, R. M.; Gallagher, D. L.; Liemohn, M. W.; Keesee, A. M.; Sarno-Smith, L. K.

    2015-07-01

    The location of the outer edge of the plasmasphere (the plasmapause) as a function of geomagnetic storm time is identified and investigated statistically in regard 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 rejoins the corotationally driven plasma while the average plasmapause location moves farther from the Earth. The results are also examined in terms of the solar wind driver. We find evidence that shows that the different categories of solar wind drivers result in different plasmaspheric configurations. During magnetic cloud-driven events the plasmaspheric drainage plume appears at the start of the main phase. During sheath-driven events the plume forms later but typically extends further in MLT.

  12. Transition between scanning tunneling microscopy images of alkane derivatives on graphite

    NASA Astrophysics Data System (ADS)

    Hibino, Masahiro; Tsuchiya, Hiroshi

    2015-12-01

    Self-assembled monolayers of alkylated sulfides containing two alkyl chains and a sulfur atom positioned at the center of the molecules were studied on a graphite surface using scanning tunneling microscopy (STM). STM images of the closed-packed alkyl chains that extend linearly from the sulfur atoms change reversibly between a zigzag pattern and an aligned bright spot pattern on a time scale of minutes. The observation times of the zigzag and aligned bright spot patterns indicate that the difference between the free energies of these two stable molecular configurations with respect to the graphite surface is smaller than their thermal energies in the presence of a solvent, and 10 times smaller than the theoretical free energy between parallel and perpendicular configurations of the alkyl chains on graphite under vacuum. The change in the contrast of the STM images occurred owing to the electronic effects that depend on the registry of the alkyl chains on the graphite surface, and not by the classical observation of transfer between parallel and perpendicular orientations of alkyl chains on the surface.

  13. Fluorescent labelling of DNA on superparamagnetic nanoparticles by a perylene bisimide derivative for cell imaging.

    PubMed

    Maltas, Esra; Malkondu, Sait; Uyar, Pembegul; Ozmen, Mustafa

    2015-03-01

    N,N'-Bis[tris-(2-aminoethyl) amine]-3,4,9,10-perylenetetracarboxylic diimide (PBI-TRIS), nonfluorescent dye was used to fluorescent labelling of DNA. For this aim, (3-aminopropyl) triethoxysilane (APTS) modified superparamagnetic iron oxide nanoparticles (SPIONs) were synthesized to provide a suitable surface for binding of DNA. Amine functionalized nanoparticles showed a high immobilization capacity (82.70%) at 25mg of nanoparticle concentration for Calf thymus DNA. Binding capacity of PBI-TRIS to DNA-SPION was also found as 1.93?M on 25mg of nanoparticles by using UV-vis spectroscopy. Binding of PBI-TRIS to DNA onto nanoparticles was also characterized by scanning electron microscopy and infrared spectroscopy. The confocal images of PBI-TRIS labelled DNA-SPION and breast cells were taken at 488 and 561.7nm of excitation wavelengths. Cell image was also compared with a commercial dye, DAPI at 403.7nm of excitation wavelength. Results showed that PBI-TRIS can be used for cell staining. PMID:25579900

  14. Flight investigation of various control inputs intended for parameter estimation

    NASA Technical Reports Server (NTRS)

    Shafer, M. F.

    1984-01-01

    NASA's F-8 digital fly-by-wire aircraft has been subjected to stability and control derivative assessments, leading to the proposal of improved control inputs for more efficient control derivative estimation. This will reduce program costs by reducing flight test and data analysis requirements. Inputs were divided into sinusoidal types and cornered types. Those with corners produced the best set of stability and control derivatives for the unaugmented flight control system mode. Small inputs are noted to have provided worse derivatives than larger ones.

  15. High-resolution three-dimensional imaging of the rich membrane structures of bone marrow-derived mast cells

    PubMed Central

    Zink, T.; Deng, Z.; Chen, H.; Yu, L.; Liu, F. T.; Liu, G. Y.

    2016-01-01

    Atomic force microscopy (AFM) enables high-resolution and three-dimensional (3D) imaging of cultured bone marrow-derived mast cells (BMMCs). Cells were immobilized by a quick centrifugation and fixation to preserve their transient cellular morphologies followed by AFM characterization in buffer. This “fix-and-look” approach preserve the structural integrity of individual cells. Well-known membrane morphologies, such as ridges and microvilli, are visualized, in consistent with prior electron microscopy observations. Additional information including the three-dimensional measurements of these characteristic features are attained from AFM topographs. Filopodia and lamellopodia, associated with cell spreading, were captured and visualized in three-dimensions. New morphologies are also revealed, such as high-density ridges and micro-craters. This investigation demonstrates that the “fix-and-look” approach followed by AFM imaging provides an effective means to characterize the membrane structure of hydrated cells with high-resolution. The quantitative imaging and measurements pave the way for systematic correlation of membrane structural features with the biological status of individual cells. PMID:18790570

  16. Lysosomal ATP imaging in living cells by a water-soluble cationic polythiophene derivative.

    PubMed

    Huang, Bing-Huan; Geng, Zhi-Rong; Ma, Xiao-Yan; Zhang, Cui; Zhang, Zhi-Yang; Wang, Zhi-Lin

    2016-09-15

    Lysosomes in astrocytes and microglia can release ATP as the signaling molecule for the cells through ca(2+)-dependent exocytosis in response to various stimuli. At present, fluorescent probes that can detect ATP in lysosomes have not been reported. In this work, we have developed a new water-soluble cationic polythiophene derivative that can be specifically localized in lysosomes and can be utilized as a fluorescent probe to sense ATP in cells. PEMTEI exhibits high selectivity and sensitivity to ATP at physiological pH values and the detection limit of ATP is as low as 10(-11)M. The probe has low cytotoxicity, good permeability and high photostability in living cells and has been applied successfully to real-time monitoring of the change in concentrations of ATP in lysosomes though fluorescence microscopy. We also demonstrated that lysosomes in Hela cells can release ATP through Ca(2+)-dependent exocytosis in response to drug stimuli. PMID:27131993

  17. Two-input programmable optical processing units.

    PubMed

    Craig, R G

    1992-11-10

    Descriptions of several two-input programmable Boolean optical processing units are presented. These units were designed specifically for use within the optical cellular logic image processor architecture. Results from an experimental implementation of one of these processors are given. Expansion upon one of these units to produce a serial full-adder and subtractor circuit is also shown to be possible. PMID:20733921

  18. Competitive Mirror Image Phage Display Derived Peptide Modulates Amyloid Beta Aggregation and Toxicity

    PubMed Central

    Rudolph, Stephan; Klein, Antonia Nicole; Tusche, Markus; Schlosser, Christine; Elfgen, Anne; Brener, Oleksandr; Teunissen, Charlotte; Gremer, Lothar; Funke, Susanne Aileen; Kutzsche, Janine; Willbold, Dieter

    2016-01-01

    Alzheimer´s disease is the most prominent type of dementia and currently no causative treatment is available. According to recent studies, oligomeric species of the amyloid beta (Aβ) peptide appear to be the most toxic Aβ assemblies. Aβ monomers, however, may be not toxic per se and may even have a neuroprotective role. Here we describe a competitive mirror image phage display procedure that allowed us to identify preferentially Aβ1–42 monomer binding and thereby stabilizing peptides, which destabilize and thereby eliminate toxic oligomer species. One of the peptides, called Mosd1 (monomer specific d-peptide 1), was characterized in more detail. Mosd1 abolished oligomers from a mixture of Aβ1–42 species, reduced Aβ1–42 toxicity in cell culture, and restored the physiological phenotype in neuronal cells stably transfected with the gene coding for human amyloid precursor protein. PMID:26840229

  19. Competitive Mirror Image Phage Display Derived Peptide Modulates Amyloid Beta Aggregation and Toxicity.

    PubMed

    Rudolph, Stephan; Klein, Antonia Nicole; Tusche, Markus; Schlosser, Christine; Elfgen, Anne; Brener, Oleksandr; Teunissen, Charlotte; Gremer, Lothar; Funke, Susanne Aileen; Kutzsche, Janine; Willbold, Dieter

    2016-01-01

    Alzheimer´s disease is the most prominent type of dementia and currently no causative treatment is available. According to recent studies, oligomeric species of the amyloid beta (Aβ) peptide appear to be the most toxic Aβ assemblies. Aβ monomers, however, may be not toxic per se and may even have a neuroprotective role. Here we describe a competitive mirror image phage display procedure that allowed us to identify preferentially Aβ1-42 monomer binding and thereby stabilizing peptides, which destabilize and thereby eliminate toxic oligomer species. One of the peptides, called Mosd1 (monomer specific d-peptide 1), was characterized in more detail. Mosd1 abolished oligomers from a mixture of Aβ1-42 species, reduced Aβ1-42 toxicity in cell culture, and restored the physiological phenotype in neuronal cells stably transfected with the gene coding for human amyloid precursor protein. PMID:26840229

  20. 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.

  1. Demonstration of a Sucrose-derived Contrast Agent for Magnetic Resonance Imaging of the GI Tract

    PubMed Central

    Martinez, Gary V.; Navath, Suryakiran; Sewda, Kamini; Rao, Venkataramanarao; Foroutan, Parastou; Alleti, Ramesh; Moberg, Valerie E.; Ahad, Ali M.; Coppola, Domenico; Lloyd, Mark C.; Gillies, Robert J.; Morse, David L.; Mash, Eugene A.

    2013-01-01

    A scaffold bearing eight terminal alkyne groups was synthesized from sucrose, and copies of an azide-terminated Gd-DOTA complex were attached via copper(I)-catalyzed azide-alkyne cycloaddition. The resulting contrast agent (CA) was administered by gavage to C3H mice. Passage of the CA through the gastrointestinal (GI) tract was followed by T1-weighted magnetic resonance imaging (MRI) over a period of 47 hours, by which time the CA had exited the GI tract. No evidence for leakage of the CA from the GI tract was observed. Thus, a new, orally administered CA for MRI of the GI tract has been developed and successfully demonstrated. PMID:23481651

  2. Demonstration of a sucrose-derived contrast agent for magnetic resonance imaging of the GI tract.

    PubMed

    Martinez, Gary V; Navath, Suryakiran; Sewda, Kamini; Rao, Venkataramanarao; Foroutan, Parastou; Alleti, Ramesh; Moberg, Valerie E; Ahad, Ali M; Coppola, Domenico; Lloyd, Mark C; Gillies, Robert J; Morse, David L; Mash, Eugene A

    2013-04-01

    A scaffold bearing eight terminal alkyne groups was synthesized from sucrose, and copies of an azide-terminated Gd-DOTA complex were attached via copper(I)-catalyzed azide-alkyne cycloaddition. The resulting contrast agent (CA) was administered by gavage to C3H mice. Passage of the CA through the gastrointestinal (GI) tract was followed by T1-weighted magnetic resonance imaging (MRI) over a period of 47h, by which time the CA had exited the GI tract. No evidence for leakage of the CA from the GI tract was observed. Thus, a new, orally administered CA for MRI of the GI tract has been developed and successfully demonstrated. PMID:23481651

  3. Improving the Altimeter Derived Geostrophic Currents Using High Resolution Sea Surface Temperature Images: A Feasibility Study

    NASA Astrophysics Data System (ADS)

    Rio, M.-H.; Santoleri, R.; Giffa, A.; Piterbarg, L.

    2015-12-01

    Accurate knowledge of spatial and temporal ocean surface currents at high resolution is essential for a variety of applications. The altimeter observing system, by providing global and repetitive measurements of the Sea Surface Height, has been by far the most exploited system to estimate ocean surface currents in the past 20 years. However it does not allow observing currents departing from the geostrophic equilibrium, nor is capable to resolve the shortest spatial scales of the currents. In order to go beyond these limits, we investigate how the high spatial and temporal resolution information from Sea Surface Temperature (SST) images can improve the altimeter currents by adapting a method first proposed by [1]. It consists in inverting the SST evolution equation for the velocity by prescribing the source and sink terms and by using the altimeter currents as background. The method feasibility is tested using simulated data based on the Mercator-Ocean system.

  4. 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.

  5. 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.

  6. Practical labeling methodology for choline-derived lipids and applications in live cell fluorescence imaging.

    PubMed

    Li, Caishun; Key, Jessie A; Jia, Feng; Dandapat, Arpan; Hur, Soo; Cairo, Christopher W

    2014-01-01

    Lipids of the plasma membrane participate in a variety of biological processes, and methods to probe their function and cellular location are essential to understanding biochemical mechanisms. Previous reports have established that phosphocholine-containing lipids can be labeled by alkyne groups through metabolic incorporation. Herein, we have tested alkyne, azide and ketone-containing derivatives of choline as metabolic labels of choline-containing lipids in cells. We also show that 17-octadecynoic acid can be used as a complementary metabolic label for lipid acyl chains. We provide methods for the synthesis of cyanine-based dyes that are reactive with alkyne, azide and ketone metabolic labels. Using an improved method for fluorophore conjugation to azide or alkyne-modified lipids by Cu(I)-catalyzed azide-alkyne cycloaddition (CuAAC), we apply this methodology in cells. Lipid-labeled cell membranes were then interrogated using flow cytometry and fluorescence microscopy. Furthermore, we explored the utility of this labeling strategy for use in live cell experiments. We demonstrate measurements of lipid dynamics (lateral mobility) by fluorescence photobleaching recovery (FPR). In addition, we show that adhesion of cells to specific surfaces can be accomplished by chemically linking membrane lipids to a functionalized surface. The strategies described provide robust methods for introducing bioorthogonal labels into native lipids. PMID:24383866

  7. Deriving a blood-mimicking fluid for particle image velocimetry in Sylgard-184 vascular models.

    PubMed

    Yousif, Majid Y; Holdsworth, David W; Poepping, Tamie L

    2009-01-01

    A new blood-mimicking fluid (BMF) has been developed for particle image velocimetry (PIV), which enables flow studies in vascular models (phantoms). A major difficulty in PIV that affects measurement accuracy is the refraction and distortion of light passing through the interface between the model and the fluid, due to the difference in refractive index (n) between the two materials. The problem can be eliminated by using a fluid with a refractive index matching that of the model. Such fluids are not commonly available, especially for vascular research where the fluid should also have a viscosity similar to human blood. In this work, a blood-mimicking fluid, composed of water (47.38% by weight), glycerol (36.94% by weight) and sodium iodide salt (15.68% by weight), was developed for compatibility with our silicone (Sylgard 184; n = 1.414) phantoms. The fluid exhibits a dynamic viscosity of 4.31+/-0.03 cP which lies within the range of human blood viscosity (4.4+/-0.6 cP). Both refractive index and viscosity were attained at 22.2+/-0.2 degrees C, which is a feasible room temperature, thus eliminating the need for a temperature-control system. The fluid will be used to study hemodynamics in vascular flow models fabricated from Sylgard 184. PMID:19964526

  8. 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.

  9. 131I-Zn-Chlorophyll derivative photosensitizer for tumor imaging and photodynamic therapy.

    PubMed

    Ocakoglu, Kasim; Er, Ozge; Kiyak, Guven; Lambrecht, Fatma Yurt; Gunduz, Cumhur; Kayabasi, Cagla

    2015-09-30

    In recent years, the photodynamic therapy studies have gained considerable attention as an alternative method to surgery, chemotherapy and radiotherapy which is commonly used to fight cancer. In this study, biological potentials of a benzyloxy bearing zinc(II) pheophorbide-a (Zn-PH-A) were investigated via in vivo and in vitro experiments. Zn-PH-A was labeled with (131)I with high efficiency (95.3 ± 2.7%) and its biodistribution studies were investigated on female Albino Wistar rats. The radiolabeled photosensitizer had been intravenously injected into the tail vein, and then the animals were sacrificed at 30, 60 and 120 min post injection. The percent of radioactivity per gram of organs (%ID/g) was determined. The radiolabeled Zn-PH-A showed high uptake in ovary. In addition, photodynamic therapy studies of the photosensitizer were conducted in EMT6, murine mammary carcinoma and HeLa, human cervix carcinoma cell lines. For the photodynamic therapy studies, the cells with Zn-PH-A were exposed to red light (650 nm) at the doses of 10-30 J/cm(2). The results showed that Zn-PH-A has stronger PDT effect in EMT6 than HeLa cell. Our present work demonstrates (131)I-labeled photosensitizer as a bifunctional agent (PDT and nuclear imaging) which could be improved in future by using EMT6 growing tumor in nude mice. PMID:26226337

  10. The cochlear size of bats and rodents derived from MRI images and histology.

    PubMed

    Hsiao, Chun Jen; Jen, Philip Hung-Sun; Wu, Chung Hsin

    2015-05-27

    From the evolutionary perspective, the ear of each animal species is built for effective processing of the biologically relevant signals used for communication and acoustically guided orientation. Because the sound pulses used by echolocating bats for orientation and rodents for communication are quite different, the basic design of the mammalian auditory system commonly shared by echolocating bats must be specialized in some manner to effectively process their species-specific sounds. The present study examines the difference in the cochlea of these animal species using MRI images and histological techniques. We report here that, although all these animal species share a similar cochlear structure, they vary in their cochlear size and turns. Bats using constant frequency-frequency-modulated pulses (CF-FM bats) and frequency-modulated pulses (FM bats) for echolocation have a larger cochlear size and more cochlear turns than rodents (mice and rats). However, CF-FM bats have the largest cochlear size and most cochlear turns. This difference in cochlear size and turns of these animal species is discussed in relation to their biologically relevant sounds and acoustic behavior. PMID:25919995

  11. 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.

  12. 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

  13. 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 μm compared to OCTRIMA, and 42 +/- 14 μm compared to RTVue MM6). All RTVue GCC measurements were significantly thicker (mean difference between 6 and 12 μm) 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.

  14. Modeling techniques and fluorescence imaging investigation of the interactions of an anthraquinone derivative with HSA and ctDNA.

    PubMed

    Fu, Zheng; Cui, Yanrui; Cui, Fengling; Zhang, Guisheng

    2016-01-15

    A new anthraquinone derivative (AORha) was synthesized. Its interactions with human serum albumin (HSA) and calf thymus DNA (ctDNA) were investigated by fluorescence spectroscopy, UV-visible absorption spectroscopy and molecular modeling. Cell viability assay and cell imaging experiment were performed using cervical cancer cells (HepG2 cells). The fluorescence results revealed that the quenching mechanism was static quenching. At different temperatures (290, 300, 310 K), the binding constants (K) and the number of binding sites (n) were determined, respectively. The positive ΔH and ΔS values showed that the binding of AORha with HSA was hydrophobic force, which was identical with the molecular docking result. Studying the fluorescence spectra, UV spectra and molecular modeling also verified that the binding mode of AORha and ctDNA might be intercalative. When HepG2 cells were treated with AORha, the fluorescence became brighter and turned green, which could be used for bioimaging. PMID:26436845

  15. Comparison of Magnetic Resonance Imaging and Serum Biomarkers for Detection of Human Pluripotent Stem Cell-Derived Teratomas.

    PubMed

    Riegler, Johannes; Ebert, Antje; Qin, Xulei; Shen, Qi; Wang, Mouer; Ameen, Mohamed; Kodo, Kazuki; Ong, Sang-Ging; Lee, Won Hee; Lee, Grace; Neofytou, Evgenios; Gold, Joseph D; Connolly, Andrew J; Wu, Joseph C

    2016-02-01

    The use of cells derived from pluripotent stem cells (PSCs) for regenerative therapies confers a considerable risk for neoplastic growth and teratoma formation. Preclinical and clinical assessment of such therapies will require suitable monitoring strategies to understand and mitigate these risks. Here we generated human-induced pluripotent stem cells (iPSCs), selected clones that continued to express reprogramming factors after differentiation into cardiomyocytes, and transplanted these cardiomyocytes into immunocompromised rat hearts post-myocardial infarction. We compared magnetic resonance imaging (MRI), cardiac ultrasound, and serum biomarkers for their ability to delineate teratoma formation and growth. MRI enabled the detection of teratomas with a volume >8mm(3). A combination of three plasma biomarkers (CEA, AFP, and HCG) was able to detect teratomas with a volume >17mm(3) and with a sensitivity of more than 87%. Based on our findings, a combination of serum biomarkers with MRI screening may offer the highest sensitivity for teratoma detection and tracking. PMID:26777057

  16. Modeling techniques and fluorescence imaging investigation of the interactions of an anthraquinone derivative with HSA and ctDNA

    NASA Astrophysics Data System (ADS)

    Fu, Zheng; Cui, Yanrui; Cui, Fengling; Zhang, Guisheng

    2016-01-01

    A new anthraquinone derivative (AORha) was synthesized. Its interactions with human serum albumin (HSA) and calf thymus DNA (ctDNA) were investigated by fluorescence spectroscopy, UV-visible absorption spectroscopy and molecular modeling. Cell viability assay and cell imaging experiment were performed using cervical cancer cells (HepG2 cells). The fluorescence results revealed that the quenching mechanism was static quenching. At different temperatures (290, 300, 310 K), the binding constants (K) and the number of binding sites (n) were determined, respectively. The positive ΔH and ΔS values showed that the binding of AORha with HSA was hydrophobic force, which was identical with the molecular docking result. Studying the fluorescence spectra, UV spectra and molecular modeling also verified that the binding mode of AORha and ctDNA might be intercalative. When HepG2 cells were treated with AORha, the fluorescence became brighter and turned green, which could be used for bioimaging.

  17. 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.

  18. 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.

  19. Multiple-Input Multiple-Output (MIMO) Linear Systems Extreme Inputs/Outputs

    DOE PAGESBeta

    Smallwood, David O.

    2007-01-01

    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 autospectral densities of the inputs are specified, the phase relationships between the inputs are derived that will minimize or maximize the trace of the autospectral 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 autospectral density matrix are derived. It is shown that other phase relationships and ordinary coherence less than one willmore » 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.« less

  20. Photometric parameter maps of the Moon derived from LROC WAC images

    NASA Astrophysics Data System (ADS)

    Sato, H.; Robinson, M. S.; Hapke, B. W.; Denevi, B. W.; Boyd, A. K.

    2013-12-01

    Spatially resolved photometric parameter maps were computed from 21 months of Lunar Reconnaissance Orbiter Camera (LROC) Wide Angle Camera (WAC) images. Due to a 60° field-of-view (FOV), the WAC achieves nearly global coverage of the Moon each month with more than 50% overlap from orbit-to-orbit. From the repeat observations at various viewing and illumination geometries, we calculated Hapke bidirectional reflectance model parameters [1] for 1°x1° "tiles" from 70°N to 70°S and 0°E to 360°E. About 66,000 WAC images acquired from February 2010 to October 2011 were converted from DN to radiance factor (I/F) though radiometric calibration, partitioned into gridded tiles, and stacked in a time series (tile-by-tile method [2]). Lighting geometries (phase, incidence, emission) were computed using the WAC digital terrain model (100 m/pixel) [3]. The Hapke parameters were obtained by model fitting against I/F within each tile. Among the 9 parameters of the Hapke model, we calculated 3 free parameters (w, b, and hs) by setting constant values for 4 parameters (Bco=0, hc=1, θ, φ=0) and interpolating 2 parameters (c, Bso). In this simplification, we ignored the Coherent Backscatter Opposition Effect (CBOE) to avoid competing CBOE and Shadow Hiding Opposition Effect (SHOE). We also assumed that surface regolith porosity is uniform across the Moon. The roughness parameter (θ) was set to an averaged value from the equator (× 3°N). The Henyey-Greenstein double lobe function (H-G2) parameter (c) was given by the 'hockey stick' relation [4] (negative correlation) between b and c based on laboratory measurements. The amplitude of SHOE (Bso) was given by the correlation between w and Bso at the equator (× 3°N). Single scattering albedo (w) is strongly correlated to the photometrically normalized I/F, as expected. The c shows an inverse trend relative to b due to the 'hockey stick' relation. The parameter c is typically low for the maria (0.08×0.06) relative to the highlands (0.47×0.16). Since c controls the fraction of backward/forward scattering in H-G2, lower c for the maria indicates more forward scattering relative to the highlands. This trend is opposite to what was expected because darker particles are usually more backscattering. However, the lower albedo of the maria is due to the higher abundance of ilmenite, which is an opaque mineral that scatters all of the light by specular reflection from the its surface. If their surface facets are relatively smooth the ilmenite particles will be forward scattering. Other factors (e.g. grain shape, grain size, porosity, maturity) besides the mineralogy might also be affecting c. The angular-width of SHOE (hs) typically shows lower values (0.047×0.02) for the maria relative to the highlands (0.074×0.025). An increase in hs for the maria theoretically suggests lower porosity or a narrower grain size distribution [1], but the link between actual materials and hs is not well constrained. Further experiments using both laboratory and spacecraft observations will help to unravel the photometric properties of the surface materials of the Moon. [1] Hapke, B.: Cambridge Univ. Press, 2012. [2] Sato, H. et al.: 42nd LPSC, abstract #1974, 2011. [3] Scholten, F. et al.: JGR, 117, E00H17, 2012. [4] Hapke, B.: Icarus, 221(2), p1079-1083, 2012.

  1. 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.

  2. 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.

  3. 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.

  4. Input-output transformation in the visuo-oculomotor loop: comparison of real-time optical imaging recordings in V1 to ocular following responses upon center-surround stimulation.

    PubMed

    Reynaud, A; Barthélemy, F V; Masson, G S; Chavane, F

    2007-11-01

    In psychophysics and physiology, it is well established that lateral interactions are crucial mechanisms to constrain response normalization and contextual modulations. To study the cortical mechanisms involved in the contextual modulation of the behavioral contrast response function, we compared in behaving monkeys the Ocular Following Response (OFR) to V1 population activity measured using Optical Imaging of Voltage-Sensitive Dyes (VSD). If contrast response functions (CRF) to a simple local stimulus are similar in V1 and in the OFR, lateral interaction leads however to quite different modulation at those two levels. At the behavioural level, contrast response function is strongly suppressed by lateral interactions, and this suppression is stronger for higher contrasts. In V1, we showed a slow dynamic of facilitation for low contrasts integration and a fast suppression operating on high contrasts. These modulatory interactions influence differently the contrast response functions, interrupting the dynamic increase of contrast sensitivity in OFR, but not in V1 response. The temporal properties of those effects lead us to hypothesize that horizontal and feedback connectivity have differential effect on low and high contrasts integration in V1. V1 provides then an input to MT whose contextual dependency is not totally determined and must be refined before affecting the behavioural OFR. PMID:18075119

  5. The integration of digital camera derived images with a computer based diabetes register for use in retinal screening.

    PubMed

    Taylor, D J; Jacob, J S; Tooke, J E

    2000-07-01

    Exeter district provides a retinal screening service based on a mobile non-mydriatic camera operated by a dedicated retinal screener visiting general practices on a 2-yearly cycle. Digital attachments to eye cameras can now provide a cost effective alternative to the use of film in population based eye screening programmes. Whilst the manufacturers of digital cameras provide a database for the storage of pictures, the images do not as yet interface readily with the rest of the patient's computer held data or allow for a sophisticated grading, reporting and administration system. The system described is a development of the Exeter diabetes register (EXSYST) which can import digitally derived pictures from either Ris-Lite TM and Imagenet TM camera systems or scanned Polaroids Pictures can be reported by the screener, checked by a consultant ophthalmologist via the hospital network, and a report, consisting of colour pictures, map of relevant pathology and referral recommendations produced. This concise report can be hard copied inexpensively on a high resolution ink-jet printer to be returned to the patient's general practitioner. Eye images remain available within the hospital diabetes centre computer network to facilitate shared care. This integrated system would form an ideal platform for the addition of computer based pathology recognition and total paperless transmission when suitable links to GP surgeries become available. PMID:10837903

  6. High-performance dendritic contrast agents for X-ray computed tomography imaging using potent tetraiodobenzene derivatives.

    PubMed

    You, Suyeon; Jung, Hye-Youn; Lee, Chaewoon; Choe, Yun Hui; Heo, Ju Young; Gang, Gil-Tae; Byun, Sang-Kyung; Kim, Won Kon; Lee, Chul-Ho; Kim, Dong-Eog; Kim, Young Il; Kim, Yoonkyung

    2016-03-28

    The use of computed tomography (CT) for vascular imaging is critical in medical emergencies requiring urgent diagnostic decisions, such as cerebral ischemia and many cardiovascular diseases. Small-molecule iodinated contrast media are often injected intravenously as radiopaque agents during CT imaging to achieve high contrast enhancement of vascular systems. The rapid excretion rate of these agents is overcome by injecting a significantly high dose of iodine, which can have serious side effects. Here we report a simple method to prepare blood-pool contrast agents for CT based on dendrimers for the first time using tetraiodobenzene derivatives as potent radiopaque moieties. Excellent in vivo safety has been demonstrated for these small (13-22nm) unimolecular water-soluble dendritic contrast agents, which exhibit high contrast enhancement in the blood-pool and effectively extend their blood half-lives. Our method is applicable to virtually any scaffold with suitable surface groups and may fulfill the current need for safer, next-generation iodinated CT contrast agents. PMID:26812006

  7. 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; Čermak, 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

  8. Development of a 111In-labeled peptide derivative targeting a chemokine receptor, CXCR4, for imaging tumors.

    PubMed

    Hanaoka, Hirofumi; Mukai, Takahiro; Tamamura, Hirokazu; Mori, Tomohiko; Ishino, Seigo; Ogawa, Kazuma; Iida, Yasuhiko; Doi, Ryuichiro; Fujii, Nobutaka; Saji, Hideo

    2006-05-01

    The chemokine receptor CXCR4 is highly expressed in tumor cells and plays an important role in tumor metastasis. The aim of this study was to develop a radiopharmaceutical for the imaging of CXCR4-expressing tumors in vivo. Based on structure-activity relationships, we designed a 14-residue peptidic CXCR4 inhibitor, Ac-TZ14011, as a precursor for radiolabeled peptides. For 111In-labeling, diethylenetriaminepentaacetic acid (DTPA) was attached to the side chain of d-Lys(8) which is distant from the residues indispensable for the antagonistic activity. In-DTPA-Ac-TZ14011 inhibited the binding of a natural ligand, stromal cell-derived factor-1alpha, to CXCR4 in a concentration-dependent manner with an IC50 of 7.9 nM (Ac-TZ14011: 1.2 nM). In biodistribution experiments, more 111In-DTPA-Ac-TZ14011 accumulated in the CXCR4-expressing tumor than in blood or muscle. Furthermore, the tumor-to-blood and tumor-to-muscle ratios were significantly reduced by coinjection of Ac-TZ14011, indicating a CXCR4-mediated accumulation in tumor. These findings suggested that 111In-DTPA-Ac-TZ14011 would be a potential agent for the imaging of CXCR4 expression in metastatic tumors in vivo. PMID:16720240

  9. Modeling and generating input processes

    SciTech Connect

    Johnson, M.E.

    1987-01-01

    This tutorial paper provides information relevant to the selection and generation of stochastic inputs to simulation studies. The primary area considered is multivariate but much of the philosophy at least is relevant to univariate inputs as well. 14 refs.

  10. Input Multiplicities in Process Control.

    ERIC Educational Resources Information Center

    Koppel, Lowell B.

    1983-01-01

    Describes research investigating potential effect of input multiplicity on multivariable chemical process control systems. Several simple processes are shown to exhibit the possibility of theoretical developments on input multiplicity and closely related phenomena are discussed. (JN)

  11. 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 Union's Seventh Framework Programme (FP7/2007-2013) under iMars grant agreement n° 607379. References: [1] Orloff et al. (2011) Boulder movement at high northern latitudes of Mars. J Geophys Res-Planet, 116: E11006-1-12; [2] Byrne et al. (2009) Distribution of mid-latitude ground ice on Mars from new impact craters. Science, 325: 1674-1676; [3] Gwinner, K., F. et al. (2010) Topography of Mars from global mapping by HRSC high-resolution digital terrain models and orthoimages: characteristics and performance. Earth and Planetary Science Letters 294, 506-519, doi:10.1016/j.epsl.2009.11.007, 2010.

  12. Input in Second Language Acquisition.

    ERIC Educational Resources Information Center

    Gass, Susan M., Ed.; Madden, Carolyn G., Ed.

    This collection of conference papers includes: "When Does Teacher Talk Work as Input?"; "Cultural Input in Second Language Learning"; "Skilled Variation in a Kindergarten Teacher's Use of Foreigner Talk"; "Teacher-Pupil Interaction in Second Language Development"; "Foreigner Talk in the University Classroom"; "Input and Interaction in the

  13. Intensive Input in Language Acquisition.

    ERIC Educational Resources Information Center

    Trimino, Andy; Ferguson, Nancy

    This paper discusses the role of input as one of the universals in second language acquisition theory. Considerations include how language instructors can best organize and present input and when certain kinds of input are more important. A self-administered program evaluation exercise using relevant theoretical and methodological contributions…

  14. Spatial and temporal variability in Moderate Resolution Imaging Spectroradiometer-derived surface albedo over global arid regions

    NASA Astrophysics Data System (ADS)

    Tsvetsinskaya, Elena A.; Schaaf, Crystal B.; Gao, Feng; Strahler, Alan H.; Dickinson, Robert E.

    2006-10-01

    We derive spectral and broadband surface albedo for global arid regions from data collected by the Moderate Resolution Imaging Spectroradiometer (MODIS) aboard the Terra spacecraft, at 1 km spatial resolution for 2001. MODIS data show considerable spatial variability both across various arid regions of the globe (from the bright deserts of northern Africa and the Arabian peninsula to substantially less reflective American and Asian deserts) and within regions (variability related to soil and rock types). For example, over arid northern Africa and the Arabian peninsula, albedo in the visible broadband varies by a factor of over 2, from the brightest sand sheets to the darkest luvisols. Few, if any, global and regional land-atmosphere models capture this observed spatial variability in surface albedo over arid regions. We suggest a scheme that relates soil groups (based on the United Nations Food and Agriculture Organization (FAO) soil classification) to MODIS-derived surface albedo statistics. This approach allows for an efficient representation in climate and weather forecasting models of the observed spatial and temporal variability in surface albedo over global deserts. Observed variability in albedo was reduced to a small (1-13, depending on the region) number of soil-related classes (end-members) that could be used in climate models. We also addressed the temporal evolution of albedo during 2001 over global deserts. Regions/soils of stable albedo with very low temporal variability were identified. For other regions/soils, temporal signals in albedo were related to ephemeral inundation with water or variations in sample size.

  15. 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.

  16. Imaging of hepatocellular carcinoma patient-derived xenografts using 89Zr-labeled anti-glypican-3 monoclonal antibody

    PubMed Central

    Yang, Xiaoyang; Liu, Hongguang; Sun, Chris K.; Natarajan, Arutselvan; Hu, Xiang; Wang, Xiaolin; Allegretta, Mark; Guttmann, Ronald D.; Gambhir, Sanjiv S.; Chua, Mei-Sze; Cheng, Zhen; So, Samuel K.

    2015-01-01

    Imaging probes for early detection of hepatocellular carcinoma (HCC) are highly desired to overcome current diagnostic limitations which lead to poor prognosis. The membrane protein glypican-3 (GPC3) is a potential molecular target for early HCC detection as it is over-expressed in >50% of HCCs, and is associated with early hepatocarcinogenesis. We synthesized the positron emission tomography (PET) probe 89Zr-DFO-1G12 by bioconjugating and radiolabeling the anti-GPC3 monoclonal antibody (clone 1G12) with 89Zr, and evaluated its tumor-targeting capacity. In vitro, 89Zr-DFO-1G12 was specifically taken up into GPC3-positive HCC cells only, but not in the GPC3-negative prostate cancer cell line (PC3). In vivo, 89Zr-DFO-1G12 specifically accumulated in subcutaneous GPC3-positive HCC xenografts only, but not in PC3 xenografts. Importantly, 89Zr-DFO-1G12 delineated orthotopic HCC xenografts from surrounding normal liver, with tumor/liver (T/L) ratios of 6.65 ± 1.33 for HepG2, and 4.29 ± 0.52 for Hep3B xenografts. It also delineated orthotopic xenografts derived from three GPC3-positive HCC patient specimens, with T/L ratios of 4.21 ± 0.64, 2.78 ± 0.26, and 2.31 ± 0.38 at 168 h p.i. Thus, 89Zr-DFO-1G12 is a highly translatable probe for the specific and high contrast imaging of GPC3-positive HCCs, which may aid early detection of HCC to allow timely intervention. PMID:24836949

  17. Imaging of hepatocellular carcinoma patient-derived xenografts using ⁸⁹Zr-labeled anti-glypican-3 monoclonal antibody.

    PubMed

    Yang, Xiaoyang; Liu, Hongguang; Sun, Chris K; Natarajan, Arutselvan; Hu, Xiang; Wang, Xiaolin; Allegretta, Mark; Guttmann, Ronald D; Gambhir, Sanjiv S; Chua, Mei-Sze; Cheng, Zhen; So, Samuel K

    2014-08-01

    Imaging probes for early detection of hepatocellular carcinoma (HCC) are highly desired to overcome current diagnostic limitations which lead to poor prognosis. The membrane protein glypican-3 (GPC3) is a potential molecular target for early HCC detection as it is over-expressed in >50% of HCCs, and is associated with early hepatocarcinogenesis. We synthesized the positron emission tomography (PET) probe (89)Zr-DFO-1G12 by bioconjugating and radiolabeling the anti-GPC3 monoclonal antibody (clone 1G12) with (89)Zr, and evaluated its tumor-targeting capacity. In vitro, (89)Zr-DFO-1G12 was specifically taken up into GPC3-positive HCC cells only, but not in the GPC3-negative prostate cancer cell line (PC3). In vivo, (89)Zr-DFO-1G12 specifically accumulated in subcutaneous GPC3-positive HCC xenografts only, but not in PC3 xenografts. Importantly, (89)Zr-DFO-1G12 delineated orthotopic HCC xenografts from surrounding normal liver, with tumor/liver (T/L) ratios of 6.65 ± 1.33 for HepG2, and 4.29 ± 0.52 for Hep3B xenografts. It also delineated orthotopic xenografts derived from three GPC3-positive HCC patient specimens, with T/L ratios of 4.21 ± 0.64, 2.78 ± 0.26, and 2.31 ± 0.38 at 168 h p.i. Thus, (89)Zr-DFO-1G12 is a highly translatable probe for the specific and high contrast imaging of GPC3-positive HCCs, which may aid early detection of HCC to allow timely intervention. PMID:24836949

  18. 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.

  19. 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.

  20. Virtual input device with diffractive optical element

    NASA Astrophysics Data System (ADS)

    Wu, Ching Chin; Chu, Chang Sheng

    2005-02-01

    As a portable device, such as PDA and cell phone, a small size build in virtual input device is more convenient for complex input demand. A few years ago, a creative idea called 'virtual keyboard' is announced, but up to now there's still no mass production method for this idea. In this paper we'll show the whole procedure of making a virtual keyboard. First of all is the HOE (Holographic Optical Element) design of keyboard image which yields a fan angle about 30 degrees, and then use the electron forming method to copy this pattern in high precision. And finally we can product this element by inject molding. With an adaptive lens design we can get a well correct keyboard image in distortion and a wilder fan angle about 70 degrees. With a batter alignment of HOE pattern lithography, we"re sure to get higher diffraction efficiency.

  1. 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; Šarić, 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

  2. Comparison of Magnetic Resonance Imaging and Serum Biomarkers for Detection of Human Pluripotent Stem Cell-Derived Teratomas

    PubMed Central

    Riegler, Johannes; Ebert, Antje; Qin, Xulei; Shen, Qi; Wang, Mouer; Ameen, Mohamed; Kodo, Kazuki; Ong, Sang-Ging; Lee, Won Hee; Lee, Grace; Neofytou, Evgenios; Gold, Joseph D.; Connolly, Andrew J.; Wu, Joseph C.

    2016-01-01

    Summary The use of cells derived from pluripotent stem cells (PSCs) for regenerative therapies confers a considerable risk for neoplastic growth and teratoma formation. Preclinical and clinical assessment of such therapies will require suitable monitoring strategies to understand and mitigate these risks. Here we generated human-induced pluripotent stem cells (iPSCs), selected clones that continued to express reprogramming factors after differentiation into cardiomyocytes, and transplanted these cardiomyocytes into immunocompromised rat hearts post-myocardial infarction. We compared magnetic resonance imaging (MRI), cardiac ultrasound, and serum biomarkers for their ability to delineate teratoma formation and growth. MRI enabled the detection of teratomas with a volume >8 mm3. A combination of three plasma biomarkers (CEA, AFP, and HCG) was able to detect teratomas with a volume >17 mm3 and with a sensitivity of more than 87%. Based on our findings, a combination of serum biomarkers with MRI screening may offer the highest sensitivity for teratoma detection and tracking. PMID:26777057

  3. Fluorescent detection and imaging of Hg(2+) using a novel phenanthroline derivative based single- and two-photon excitation.

    PubMed

    Zhang, Xian; Li, Long-long; Liu, Ying-kai

    2016-02-01

    A novel phenanthroline derivative, 4-[4-(N-methyl)styrene]-imidazo[4,5-f][1,10]phenanthroline-benzene iodated salt (MSIPBI), was synthesized, and the linear absorption and fluorescent spectra of MSIPBI in different solvents were investigated. The photophysical properties in unbound and in ligand-metal complexes were evaluated by UV absorption and one- and two-photon fluorescent spectra, and the quantum yields, two-photon active cross-sections and the binding constant of dye-metal were calculated. The results indicated that MSIPBI has a large Stokes shift (more than 167nm), and the dye was selective and sensitive for the detection of Hg(2+) with a two-photon active cross-section of 55.5GM in tris-HCl buffer solution at 800nm. Furthermore, the results of the fluorescence microscopy imaging indicated that MSIPBI is an efficient fluorescent probe for the detection of Hg(2+) in living cells by one- and two-photon excitation. Moreover, the experiments of determination Hg(2+) in river water and tap water were finished. PMID:26652448

  4. 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

  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. Nanoparticles based on quantum dots and a luminol derivative: implications for in vivo imaging of hydrogen peroxide by chemiluminescence resonance energy transfer.

    PubMed

    Lee, Eun Sook; Deepagan, V G; You, Dong Gil; Jeon, Jueun; Yi, Gi-Ra; Lee, Jung Young; Lee, Doo Sung; Suh, Yung Doug; Park, Jae Hyung

    2016-03-01

    Overproduction of hydrogen peroxide is involved in the pathogenesis of inflammatory diseases such as cancer and arthritis. To image hydrogen peroxide via chemiluminescence resonance energy transfer in the near-infrared wavelength range, we prepared quantum dots functionalized with a luminol derivative. PMID:26857551

  8. 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…

  9. 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

  10. Synthesis and evaluation of novel F-18 labeled 4-aminoquinazoline derivatives: potential PET imaging agents for tumor detection.

    PubMed

    Chen, Yurong; Feng, Man; Li, Shilei; Xu, Jingli; Ning, Hongyu; He, Yong; Wang, Xiao; Ding, Rui; Qi, Chuanmin

    2012-07-15

    Three novel (18)F-labeled 4-aminoquinazoline derivatives, N-(3-chloro-4-fluorophenyl)-6-(2-[(18)F]fluoroethoxy)-7-methoxyquinazolin-4-amine([(18)F]1), N-(3-ethynylphenyl)-6-(2-[(18)F]fluoroethoxy)-7-methoxyquinazolin-4-amine([(18)F]2), and N-(3-bromophenyl)-6-(2-[(18)F]fluoroethoxy)-7-methoxyquinazolin-4-amine([(18)F]3) were synthesized and radiolabeled by two-step reaction with overall radiochemical yield of 21-24% (without decay corrected). Then we carried out their biodistribution experiments in S180 tumor-bearing mice. Results showed that they had certain concentration accumulation in tumor and fast clearance from muscle and blood. It was encouraging that [(18)F]3 was competitive among three (18)F-labeled 4-aminoquinazoline derivatives in some aspects such as tumor/muscle uptake ratio reaching 7.70 at 60 min post-injection, tumor/blood uptake ratio reaching 6.61 at 120 min post-injection. So we compared radioactivity characteristics of [(18)F]3 with those of [(18)F]-FDG and L-[(18)F]-FET in the same animal model. The absolute radioactivity uptake of [(18)F]3 in tumor reached 3.31 at 60 min p.i., which was slightly higher than [(18)F]-FDG (2.16) and L-[(18)F]-FET (2.75) at the same time phase. For [(18)F]3, tumor/muscle uptake ratio peaked 7.70 at 60 min, which was obviously superior to those of [(18)F]-FDG and L-[(18)F]-FET at all time points. The tumor/brain uptake ratios of [(18)F]3 were 10.36, 17.42, 41.11 at 30 min, 60 min and 120 min post-injection, respectively, and are much higher than those of L-[(18)F] FET (2.54, 2.92 and 2.95) and [(18)F]-FDG (0.61, 1.02 and 1.33) at the same time points. All these results indicate that [(18)F]3 is promising to become a potential PET tumor imaging agent. PMID:22704892

  11. Temporal and Spatial Assessment of Yearly Solar Maps Derived from Satellite Images over the UAE and Qatar

    NASA Astrophysics Data System (ADS)

    Eissa, Y.; Marpu, P. R.; Ghedira, H.; Chiesa, M.

    2012-12-01

    The unique climate of countries located within the Arabian Peninsula, characterized by high dust concentrations, high humidity and modest cloud coverage, requires regional models to retrieve the solar irradiance components from satellite images. An artificial neural network (ANN) model has shown promising results in estimating the direct normal, diffuse horizontal and global horizontal irradiances using thermal satellite channels over the United Arab Emirates (UAE). This model is trained with six thermal channels of the SEVIRI instrument, onboard Meteosat Second Generation, along with the solar zenith angle, day number, solar time and eccentricity correction. The outputs of this model are the solar irradiance components at 15-min temporal and 3-km spatial resolutions, which are then utilized to derive the daily, monthly and yearly irradiation maps over the UAE and Qatar. The purpose of this research is to examine the temporal and spatial variations for annual irradiation maps over the UAE and Qatar, derived using the ANN approach. For the period ranging from 2008 to 2010, the year of 2009 shows the lowest annual direct normal and global horizontal irradiation, and the highest diffuse horizontal irradiation. That is due to frequent dust events which occurred during 2009. The annual direct normal irradiation maps for 2008 to 2010 show the same trend, with the higher irradiation values in the southern area of UAE and the values decreasing as the coast approaches in the northern region. For any given year, Qatar generally shows lower direct normal irradiation values than the UAE. This might be explained by higher humidity in Qatar due to its coastal climate. As for the annual diffuse horizontal irradiation maps, the lower irradiation values are observed in the southern area of UAE and along some coastal regions, with the higher values being in the middle. Qatar shows higher values in the western region, due to the increased airborne dust coming from Saudi Arabia, as opposed to the eastern coast which is along the Arabian Gulf. The annual global horizontal irradiation maps show less spatial variations. For the UAE the values consistently increase from north to south, while for Qatar lower values are observed along the eastern coast and the higher values are in the inland and southern locations. The direct normal irradiation map over the UAE and Qatar for the year 2010, which had values greater than 2008 and 2009.

  12. Coordination Polymers Derived from Non-Steroidal Anti-Inflammatory Drugs for Cell Imaging and Drug Delivery.

    PubMed

    Paul, Mithun; Dastidar, Parthasarathi

    2016-01-01

    A new series of Mn(II) coordination polymers, namely, [{Mn(L)(H2 O)2 }⋅2 Nap]∞ (CP1), [{Mn(L)(Ibu)2 (H2 O)2 }]∞ (CP2), [{Mn(L)(Flr)2 (H2 O)2 }]∞ (CP3), [{Mn(L)(Ind)2 (H2 O)2 }⋅H2 O]∞ (CP4), [{Mn2 (L)2 (μ-Flu)4 (H2 O)}⋅L]∞ (CP5), [{Mn2 (L)2 (μ-Tol)4 (H2 O)2 }]∞ (CP6) and [{Mn2 (L)2 (μ-Mef)4 (H2 O)2 }]∞ (CP7) (Nap=naproxen, Ibu=ibuprofen, Flr=flurbiprofen, Ind=indometacin, Flu=flufenamic acid, Tol=tolfenamic acid and Mef=mefenamic acid) derived from various non-steroidal anti-inflammatory drugs (NSAIDs) and the organic linker 1,2-bis(4-pyridyl)ethylene (L) have been synthesized with the aim of being used for cell imaging and drug delivery. Single-crystal X-ray diffraction (SXRD) studies revealed that the NSAID molecules were part of the coordination polymeric network either through coordination to the metal center (in the majority of the cases) or through hydrogen bonding. Remarkably, all the Mn(II) coordination polymers were found to be soluble in DMSO, thereby making them particularly suitable for the desired biological applications. Two of the coordination polymers (namely, CP1 and CP3) reported herein, were found to be photoluminescent both in the solid as well as in the solution state. Subsequent experiments (namely, MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide), and PGE2 (prostaglandin E2 ) assays) established their biocompatibility and anti-inflammatory response. In vitro studies by using a macrophage cell line (i.e., RAW 264.7) revealed that both CP1 and CP3 were excellent cell imaging agents. Finally, biodegradability studies under simulated physiological conditions in phosphate-buffered saline (PBS) at pH 7.6 showed that slow and sustained release of the corresponding NSAID was indeed possible from both CP1 and CP3. PMID:26660274

  13. Evaluation of Modified PEG-Anilinoquinazoline Derivatives as Potential Agents for EGFR Imaging in Cancer by Small Animal PET

    PubMed Central

    Mishani, Eyal; Nanni, Cristina; Landuzzi, Lorena; Boschi, Stefano; Nicoletti, Giordano; Dissoki, Samar; Paterini, Paola; Piccaluga, Pier Poalo; Lodi, Filippo; Lollini, Pier-Luigi; Fanti, Stefano; Biasco, Guido

    2010-01-01

    Purpose The in vivo evaluation of three modified polyethylene glycol (PEG)-anilinoquinazoline derivatives labeled with 124I, 18F, and 11C as potential positron emission tomography (PET) bioprobes for visualizing epidermal growth factor receptor (EGFR) in cancer using small animal PET. Procedures Xenograft mice with the human glioblastoma cell lines U138MG (lacking EGFR expression) and U87MG.wtEGFR (transfected with an overexpressing human wild-type EGFR gene) were used. Static and dynamic PET imaging was conducted for all three PEGylated compounds. Tumor necrosis, microvessel density, and EGFR levels were evaluated by histopathology and enzyme-linked immunosorbent assay. Results Nineteen animal models were generated (two U138MG, three U87MG, 14 with both U138MG and U87MG bilateral masses). In static images, a slight increase in tracer uptake was observed in tumors, but in general, there was no retention of tracer uptake over time and no difference in uptake between U138MG and U87MG masses. In addition, no significant uptake was demonstrated in dynamic scans of the 18F-PEG tracer. No necrosis was present except in four animals. MVD was 9.6 and 48 microvessels/×400 field in the U138GM and U87GM masses, respectively (p = 0.00008). Similarly, the microvessel grades were generally higher in the U87GM group (p = 0.002). Total EGFR amount was higher in U87MG than U138MG masses (p = 0.001), but the ratio of activated (pY1068) to total EGFR did not differ (p = 0.95). Conclusions PEGylated tracers labeled with 11C, 124I, and 18F showed no significant difference in uptake between U138MG and U87MG glioblastoma xenograft mice. The tracer binding with EGFR could be influenced by activation of the tyrosine kinase portion of the receptor which was similar in U138MG and U87MG. Despite these results, these tracers should be investigated in animal models with mutant EGFR genes to determine whether aberrant receptor function plays a role in tumor uptake. PMID:20379787

  14. Nile Red Derivative-Modified Nanostructure for Upconversion Luminescence Sensing and Intracellular Detection of Fe(3+) and MR Imaging.

    PubMed

    Wei, Ruoyan; Wei, Zuwu; Sun, Lining; Zhang, Jin Z; Liu, Jinliang; Ge, Xiaoqian; Shi, Liyi

    2016-01-13

    Iron ion (Fe(3+)) which is the physiologically most abundant and versatile transition metal in biological systems, has been closely related to many certain cancers, metabolism, and dysfunction of organs, such as the liver, heart, and pancreas. In this Research Article, a novel Nile red derivative (NRD) fluorescent probe was synthesized and, in conjunction with polymer-modified core-shell upconversion nanoparticles (UCNPs), demonstrated in the detection of Fe(3+) ion with high sensitivity and selectivity. The core-shell UCNPs were surface modified using a synthesized PEGylated amphiphilic polymer (C18PMH-mPEG), and the resulting mPEG modified core-shell UCNPs (mPEG-UCNPs) show good water solubility. The overall Fe(3+)-responsive upconversion luminescence nanostructure was fabricated by linking the NRD to the mPEG-UCNPs, denoted as mPEG-UCNPs-NRD. In the nanostructure, the core-shell UCNPs, NaYF4:Yb,Er,Tm@NaGdF4, serve as the energy donor while the Fe(3+)-responsive NRD as the energy acceptor, which leads to efficient luminescence resonance energy transfer (LRET). The mPEG-UCNPs-NRD nanostructure shows high selectivity and sensitivity for detecting Fe(3+) in water. In addition, benefited from the good biocompatibility, the nanostructure was successfully applied for detecting Fe(3+) in living cells based on upconversion luminescence (UCL) from the UCNPs. Furthermore, the doped Gd(3+) ion in the UCNPs endows the mPEG-UCNPs-NRD nanostructure with effective T1 signal enhancement, making it a potential magnetic resonance imaging (MRI) contrast agent. This work demonstrates a simple yet powerful strategy to combine metal ion sensing with multimodal bioimaging based on upconversion luminescence for biomedical applications. PMID:26702512

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

    NASA Astrophysics Data System (ADS)

    Jacques, J.; Fraix-Burnet, D.

    2014-12-01

    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.

  16. Deformation field correction for spatial normalization of PET images using a population-derived partial least squares model

    PubMed Central

    Bilgel, Murat; Carass, Aaron; Resnick, Susan M.; Wong, Dean F.; Prince, Jerry L.

    2014-01-01

    Spatial normalization of positron emission tomography (PET) images is essential for population studies, yet work on anatomically accurate PET-to-PET registration is limited. We present a method for the spatial normalization of PET images that improves their anatomical alignment based on a deformation correction model learned from structural image registration. To generate the model, we first create a population-based PET template with a corresponding structural image template. We register each PET image onto the PET template using deformable registration that consists of an affine step followed by a diffeomorphic mapping. Constraining the affine step to be the same as that obtained from the PET registration, we find the diffeomorphic mapping that will align the structural image with the structural template. We train partial least squares (PLS) regression models within small neighborhoods to relate the PET intensities and deformation fields obtained from the diffeomorphic mapping to the structural image deformation fields. The trained model can then be used to obtain more accurate registration of PET images to the PET template without the use of a structural image. A cross validation based evaluation on 79 subjects shows that our method yields more accurate alignment of the PET images compared to deformable PET-to-PET registration as revealed by 1) a visual examination of the deformed images, 2) a smaller error in the deformation fields, and 3) a greater overlap of the deformed anatomical labels with ground truth segmentations. PMID:25383393

  17. Cross-sensor SAR image offsets for deriving coseismic displacements: Application to the 2001 Bhuj (India) earthquake using ERS and Envisat data

    NASA Astrophysics Data System (ADS)

    Wang, T.; Wei, S.; Jonsson, S.; Avouac, J. P.

    2014-12-01

    Synthetic Aperture Radar (SAR) is a powerful imaging technique for measuring ground deformation, either through Interferometric SAR (InSAR) or image offset tracking. However, these methods are only applied to SAR images acquired by the same satellite, which limits the measurement capability for many earthquakes. Here we propose a novel approach that allows for calculating offsets between images acquired from the European ERS and Envisat satellites. To achieve this cross-sensor offset calculation, we first coregister pre-event (ERS) and post-event (Envisat) SAR images separately to generate averaged pre- and post-event SAR amplitude maps. We then compute the orbital offsets between these two maps in order to resample the ERS average map onto the grid of the averaged Envisat image. We finally calculate the cross-sensor image offsets based on cross-correlating selected sub-images distributed throughout the coregistered averaged SAR maps. Application to the 2001 Bhuj earthquake reveals, for the first time, its near-field coseismic displacement field right above the epicenter. We compare our measurements with the surface displacement field predicted from the published source model of Copley et al. [2011]. This model was derived from tele-seismic waveforms and limited far-field geodetic data. The comparison between the two displacement maps shows consistent displacement patterns, yet a systematic shift, which likely is due to the limited near-fault resolution of the data used in the previous model. We then perform a joint inversion using the newly derived SAR image offsets and tele-seismic waveforms. The preferred source model suggests a compact slip pattern at depths of 20-30 km with a peak slip of ~10 meters and a fairly short rise time (<3s). The large slip rate and low attenuation in the crust are likely responsible for the widely felt ground shaking despite of its compact source area. The result demonstrates that it is possible to correlate non-coherent SAR images acquired by different sensors to measure surface displacements. This approach extends further the possibility of mining the archive of SAR images for various types of earth-science studies.

  18. Eyewear-style three-dimensional endoscope derived from microstructured polymer fiber with the function of image transmission

    NASA Astrophysics Data System (ADS)

    Kong, De-Peng; Wang, Li-Li; He, Zheng-Quan; Chu, Jiu-Rong; Ma, Tian

    2013-02-01

    A method of fabricating multi-core polymer image fiber is proposed. Image fiber preform is fabricated by stacking thousands of polymer fibers each with a 0.25-mm diameter orderly in a die by only one step. The preform is heated and stretched into image fiber with an outer diameter of 2 mm. Then a portable eyewear-style three-dimensional (3D) endoscope system is designed, fabricated, and characterized. This endoscopic system is composed of two graded index lenses, two pieces of 0.35-m length image guide fibers, and a pair of oculars. It shows good flexibility and portability, and can provide the depth information accordingly.

  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. Derivation of a MODIS-compatible enhanced vegetation index from visible infrared imaging radiometer suite spectral reflectances using vegetation isoline equations

    NASA Astrophysics Data System (ADS)

    Obata, Kenta; Miura, Tomoaki; Yoshioka, Hiroki; Huete, Alfredo R.

    2013-01-01

    We developed a unique methodology that spectrally translates the enhanced vegetation index (EVI) across sensors for data continuity based on vegetation isoline equations and derived a moderate resolution imaging spectroradiometer (MODIS)-compatible EVI for the visible/infrared imager/radiometer suite (VIIRS) sensor. The derived equation had four coefficients that were a function of soil, canopy, and atmosphere, e.g., soil line slope, leaf area index (LAI), and aerosol optical thickness (AOT). The PROSAIL canopy reflectance and 6S atmospheric models were employed to numerically characterize the MODIS-compatible VIIRS EVI. MODIS-compatible VIIRS EVI values only differed from those of MODIS EVI by, at most, 0.002 EVI units, whereas VIIRS and MODIS EVI values differed by 0.018 EVI units. The derived coefficients were sensitive mainly to LAI and AOT for the full- and a partial-covered canopy, respectively. The MODIS-compatible EVI resulted in a reasonable level of accuracy when the coefficients were fixed at values found via optimization for model-simulated and actual sensor data (83 and 41% reduction in the root mean square error, respectively), demonstrating the potential practical utility of the derived equation. The developed methodology can be used to obtain a spectrally compatible EVI for any pair of sensors in the data continuity context.

  1. Self-Assembly of Electron Donor-Acceptor-Based Carbazole Derivatives: Novel Fluorescent Organic Nanoprobes for Both One- and Two-Photon Cellular Imaging.

    PubMed

    Zhang, Jinfeng; Chen, Wencheng; Kalytchuk, Sergii; Li, King Fai; Chen, Rui; Adachi, Chihaya; Chen, Zhan; Rogach, Andrey L; Zhu, Guangyu; Yu, Peter K N; Zhang, Wenjun; Cheah, Kok Wai; Zhang, Xiaohong; Lee, Chun-Sing

    2016-05-11

    In this study, we report fluorescent organic nanoprobes with intense blue, green, and orange-red emissions prepared by self-assembling three carbazole derivatives into nanorods/nanoparticles. The three compounds consist of two or four electron-donating carbazole groups linked to a central dicyanobenzene electron acceptor. Steric hindrance from the carbazole groups leads to noncoplanar 3D molecular structures favorable to fluorescence in the solid state, while the donor-acceptor structures endow the molecules with good two-photon excited emission properties. The fluorescent organic nanoprobes exhibit good water dispersibility, low cytotoxicity, superior resistance against photodegradation and photobleaching. Both one- and two-photon fluorescent imaging were shown in the A549 cell line. Two-photon fluorescence imaging with the fluorescent probes was demonstrated to be more effective in visualizing and distinguishing cellular details compared to conventional one-photon fluorescence imaging. PMID:27097920

  2. Comparison of correlation performance of smart ternary phase-amplitude filters with gray-scale and binary input scenes

    NASA Astrophysics Data System (ADS)

    Flannery, David L.; Phillips, William E., III; Reel, Richard L.; Goldstein, Dennis H.

    1992-07-01

    The ternary phase-amplitude filter (TPAF) is by definition restricted to the modulation values -1, 0, and 1, thus comprising a binary phase-only filter (BPOF) multiplied by a binary- amplitude pattern, i.e., a region of support. The TPAF offers an attractive combination of real-time implementation with available devices and good correlation performance. Smart (optimized distortion-invariant) TPAF formulations have been developed. The TPAF enables filter implementation with magneto-optic devices and these devices also can also be used for image input if gray scale scenes can be binarized while preserving good correlation performance. We provide simulation results addressing the comparative performance of TPAF correlation using gray scale and binary images derived from identical edge-enhanced version of original scenes. Experimental correlations verifying the results for the binary input cases are provided.

  3. 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

  4. Characterization of membrane protein interactions in plasma membrane derived vesicles with quantitative imaging Förster resonance energy transfer.

    PubMed

    Sarabipour, Sarvenaz; Del Piccolo, Nuala; Hristova, Kalina

    2015-08-18

    Here we describe an experimental tool, termed quantitative imaging Förster resonance energy transfer (QI-FRET), that enables the quantitative characterization of membrane protein interactions. The QI-FRET methodology allows us to acquire binding curves and calculate association constants for complex membrane proteins in the native plasma membrane environment. The method utilizes FRET detection, and thus requires that the proteins of interest are labeled with florescent proteins, either FRET donors or FRET acceptors. Since plasma membranes of cells have complex topologies precluding the acquisition of two-dimensional binding curves, the FRET measurements are performed in plasma membrane derived vesicles that bud off cells as a result of chemical or osmotic stress. The results overviewed here are acquired in vesicles produced with an osmotic vesiculation buffer developed in our laboratory, which does not utilize harsh chemicals. The concentrations of the donor-labeled and the acceptor-labeled proteins are determined, along with the FRET efficiencies, in each vesicle. The experiments utilize transient transfection, such that a wide variety of concentrations is sampled. Then, data from hundreds of vesicles are combined to yield dimerization curves. Here we discuss recent findings about the dimerization of receptor tyrosine kinases (RTKs), membrane proteins that control cell growth and differentiation via lateral dimerization in the plasma membrane. We focus on the dimerization of fibroblast growth factor receptor 3 (FGFR3), a RTK that plays a critically important role in skeletal development. We study the role of different FGFR3 domains in FGFR3 dimerization in the absence of ligand, and we show that FGFR3 extracellular domains inhibit unliganded dimerization, while contacts between the juxtamembrane domains, which connect the transmembrane domains to the kinase domains, stabilize the unliganded FGFR3 dimers. Since FGFR3 has been documented to harbor many pathogenic single amino acid mutations that cause skeletal and cranial dysplasias, as well as cancer, we also study the effects of these mutations on dimerization. First, we show that the A391E mutation, linked to Crouzon syndrome with acanthosis nigricans and to bladder cancer, significantly enhances FGFR3 dimerization in the absence of ligand and thus induces aberrant receptor interactions. Second, we present results about the effect of three cysteine mutations that cause thanatophoric dysplasia, a lethal phenotype. Such cysteine mutations have been hypothesized previously to cause constitutive dimerization, but we find instead that they have a surprisingly modest effect on dimerization. Most of the studied pathogenic mutations also altered FGFR3 dimer structure, suggesting that both increases in dimerization propensities and changes in dimer structure contribute to the pathological phenotypes. The results acquired with the QI-FRET method further our understanding of the interactions between FGFR3 molecules and RTK molecules in general. Since RTK dimerization regulates RTK signaling, our findings advance our knowledge of RTK activity in health and disease. The utility of the QI-FRET method is not restricted to RTKs, and we thus hope that in the future the QI-FRET method will be applied to other classes of membrane proteins, such as channels and G protein-coupled receptors. PMID:26244699

  5. New Local DEM Derived from Combination of High-Resolution Viking Images and the High-Precision MOLA Data Set

    NASA Astrophysics Data System (ADS)

    Baratoux, D. B.; Delacourt, C. D.; Allemand, P. A.

    2001-03-01

    Topographic mapping is essential for understanding geologic processes. DEM of Mars can be computed from interpolated MOLA or stereophotogrammetric analysis of Viking images. We present a method to registrate and combine these two data sets.

  6. Aerosol and Cloud Properties at the Huygens Entry Site as Derived from the Descent Imager/Spectral

    NASA Technical Reports Server (NTRS)

    Doose, L. R.; Engel, S.; Tomasko, M. G.; Dafoe, L. E.; West, R.; Lemmon, M.

    2005-01-01

    The Huygens Probe descended through Titan s atmosphere on January 14, 2005. The Descent Imager/Spectral Radiometer (DISR) instrument made optical measurements which constrain the nature and vertical distribution and of the aerosols in the atmosphere.

  7. Long-term time-lapse multimodal intravital imaging of regeneration and bone-marrow-derived cell dynamics in skin

    PubMed Central

    Graf, Benedikt W.; Chaney, Eric J.; Marjanovic, Marina; Adie, Steven G.; De Lisio, Michael; Valero, M. Carmen; Boppart, Marni D.; Boppart, Stephen A.

    2014-01-01

    A major challenge for translating cell-based therapies is understanding the dynamics of cells and cell populations in complex in vivo environments. Intravital microscopy has shown great promise for directly visualizing cell behavior in vivo. However, current methods are limited to relatively short imaging times (hours), by ways to track cell and cell population dynamics over extended time-lapse periods (days to weeks to months), and by relatively few imaging contrast mechanisms that persist over extended investigations. We present technology to visualize and quantify complex, multifaceted dynamic changes in natural deformable skin over long time periods using novel multimodal imaging and a non-rigid image registration method. These are demonstrated in green fluorescent protein (GFP) bone marrow (BM) transplanted mice to study dynamic skin regeneration. This technology provides a novel perspective for studying dynamic biological processes and will enable future studies of stem, immune, and tumor cell biology in vivo. PMID:25089085

  8. Spatially and Temporally Resolved Images of Electric Field and Conductivity derived from Incoherent Scatter Radar measurements (Invited)

    NASA Astrophysics Data System (ADS)

    Nicolls, M. J.; Cosgrove, R. B.; Bahcivan, H.; Hampton, D. L.; Conde, M.

    2013-12-01

    Auroral forms involve spatial scales that are small in comparison with the magnetosphere-ionosphere (MI) system, and yet these forms are thought to be closely tied to the overall system response. Spatially resolved measurements of the horizontal ionospheric current can, in principle, be used to determine the field-aligned currents that are responsible for energy transfer between the ionosphere and magnetosphere, leading to heating and acceleration of the neutral gas, substorms, and other instabilities. Optical emissions allow imaging the dynamics of auroral forms in 2D, and our picture of neutral wind forcing has progressed significantly with spatially resolved optical spectrometry. However, similarly resolved images of electric fields, conductivities, and ultimately currents are not yet routinely available, although they are needed to properly characterize the magnetosphere-ionosphere interaction. Multi-beam incoherent scatter radars such as the system at Poker Flat have the potential to fill this gap. However, there exists a potentially crippling trade-off between time resolution, spatial resolution, and spatial coverage, in addition to the inherent difficulty of resolving a vector field with a monostatic radar. In this work, we attempt to overcome some of these difficulties by exploring mathematical imaging and data fusion techniques, and obtain two-dimensional images of the electric field, and three-dimensional images of the conductivity. We consider applications to stable auroral arcs, substorm triggering events, and the westward-traveling surge, and assess the reliability of the images produced, with the ultimate goal being diagnosis of ionospheric current closure.

  9. Multiple input/output random vibration control system

    NASA Technical Reports Server (NTRS)

    Unruh, James F.

    1988-01-01

    A multi-input/output random vibration control algorithm was developed based on system identification concepts derived from random vibration spectral analysis theory. The unique features of the algorithm are: (1) the number of input excitors and the number of output control responses need not be identical; (2) the system inverse response matrix is obtained directly from the input/output spectral matrix; and (3) the system inverse response matrix is updated every control loop cycle to accommodate system amplitude nonlinearities. A laboratory demonstration case of two imputs with three outputs is presented to demonstrate the system capabilities.

  10. 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.

  11. Segmentation and learning in the quantitative analysis of microscopy images

    NASA Astrophysics Data System (ADS)

    Ruggiero, Christy; Ross, Amy; Porter, Reid

    2015-02-01

    In material science and bio-medical domains the quantity and quality of microscopy images is rapidly increasing and there is a great need to automatically detect, delineate and quantify particles, grains, cells, neurons and other functional "objects" within these images. These are challenging problems for image processing because of the variability in object appearance that inevitably arises in real world image acquisition and analysis. One of the most promising (and practical) ways to address these challenges is interactive image segmentation. These algorithms are designed to incorporate input from a human operator to tailor the segmentation method to the image at hand. Interactive image segmentation is now a key tool in a wide range of applications in microscopy and elsewhere. Historically, interactive image segmentation algorithms have tailored segmentation on an image-by-image basis, and information derived from operator input is not transferred between images. But recently there has been increasing interest to use machine learning in segmentation to provide interactive tools that accumulate and learn from the operator input over longer periods of time. These new learning algorithms reduce the need for operator input over time, and can potentially provide a more dynamic balance between customization and automation for different applications. This paper reviews the state of the art in this area, provides a unified view of these algorithms, and compares the segmentation performance of various design choices.

  12. 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.

  13. Small Iminocoumarin Derivatives as Red Emitters: From Biological Imaging to Highly Photoluminescent Non-doped Micro- and Nanofibres.

    PubMed

    Khemakhem, Kacem; Soulié, Marine; Brousses, Rémy; Ammar, Houcine; Abid, Souhir; Fery-Forgues, Suzanne

    2015-05-18

    The fluorescence properties of four derivatives of 3-thienyl-2-(N-dicyanovinyl)iminocoumarin, bearing a diethylamino group in the 7-position or a methoxy group in the 6, 7 and 8 positions, were compared in solution and in the solid state. The 7-diethylamino derivative was strongly fluorescent in various solvents, with marked solvatochromism. Its fluorescence was quenched by aggregation. In contrast, the methoxy derivatives were only moderately or weakly fluorescent in solution, but two of them were strongly photoluminescent in the crystalline state, owing to favourable molecular packing. The 6-methoxy derivative even exhibited spectacular crystallization-enhanced emission, examples of which are particularly rare for this type of dyes. Dyes were tested for biological use. The 7-diethylamino derivative led to particularly strong fluorescence staining of the cytoplasm of HCT-116 colon cancer cells. No fading was observed over prolonged illumination by the microscope light beam, but a phototoxic effect was detected. The use of the dyes as red-emitting materials was also investigated. Using easy-to-implement preparation methods, the compounds self- assembled to give one-dimensional nano- and microsized particles, including millimeter-long microfibres that exhibited clear wave-guiding properties. This study shows the value of these low molecular-weight molecules for the preparation of new orange and red-emitting fluorescent materials based on totally pure dye. PMID:25873140

  14. 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.

  15. Analog Input Data Acquisition Software

    NASA Technical Reports Server (NTRS)

    Arens, Ellen

    2009-01-01

    DAQ Master Software allows users to easily set up a system to monitor up to five analog input channels and save the data after acquisition. This program was written in LabVIEW 8.0, and requires the LabVIEW runtime engine 8.0 to run the executable.

  16. World Input-Output Network.

    PubMed

    Cerina, Federica; Zhu, Zhen; Chessa, Alessandro; Riccaboni, Massimo

    2015-01-01

    Production systems, traditionally analyzed as almost independent national systems, are increasingly connected on a global scale. Only recently becoming available, the World Input-Output Database (WIOD) is one of the first efforts to construct the global multi-regional input-output (GMRIO) tables. By viewing the world input-output system as an interdependent network where the nodes are the individual industries in different economies and the edges are the monetary goods flows between industries, we analyze respectively the global, regional, and local network properties of the so-called world input-output network (WION) and document its evolution over time. At global level, we find that the industries are highly but asymmetrically connected, which implies that micro shocks can lead to macro fluctuations. At regional level, we find that the world production is still operated nationally or at most regionally as the communities detected are either individual economies or geographically well defined regions. Finally, at local level, for each industry we compare the network-based measures with the traditional methods of backward linkages. We find that the network-based measures such as PageRank centrality and community coreness measure can give valuable insights into identifying the key industries. PMID:26222389

  17. World Input-Output Network

    PubMed Central

    Cerina, Federica; Zhu, Zhen; Chessa, Alessandro; Riccaboni, Massimo

    2015-01-01

    Production systems, traditionally analyzed as almost independent national systems, are increasingly connected on a global scale. Only recently becoming available, the World Input-Output Database (WIOD) is one of the first efforts to construct the global multi-regional input-output (GMRIO) tables. By viewing the world input-output system as an interdependent network where the nodes are the individual industries in different economies and the edges are the monetary goods flows between industries, we analyze respectively the global, regional, and local network properties of the so-called world input-output network (WION) and document its evolution over time. At global level, we find that the industries are highly but asymmetrically connected, which implies that micro shocks can lead to macro fluctuations. At regional level, we find that the world production is still operated nationally or at most regionally as the communities detected are either individual economies or geographically well defined regions. Finally, at local level, for each industry we compare the network-based measures with the traditional methods of backward linkages. We find that the network-based measures such as PageRank centrality and community coreness measure can give valuable insights into identifying the key industries. PMID:26222389

  18. The advanced LIGO input optics

    NASA Astrophysics Data System (ADS)

    Mueller, Chris L.; Arain, Muzammil A.; Ciani, Giacomo; DeRosa, Ryan. T.; Effler, Anamaria; Feldbaum, David; Frolov, Valery V.; Fulda, Paul; Gleason, Joseph; Heintze, Matthew; Kawabe, Keita; King, Eleanor J.; Kokeyama, Keiko; Korth, William Z.; Martin, Rodica M.; Mullavey, Adam; Peold, Jan; Quetschke, Volker; Reitze, David H.; Tanner, David B.; Vorvick, Cheryl; Williams, Luke F.; Mueller, Guido

    2016-01-01

    The advanced LIGO gravitational wave detectors are nearing their design sensitivity and should begin taking meaningful astrophysical data in the fall of 2015. These resonant optical interferometers will have unprecedented sensitivity to the strains caused by passing gravitational waves. The input optics play a significant part in allowing these devices to reach such sensitivities. Residing between the pre-stabilized laser and the main interferometer, the input optics subsystem is tasked with preparing the laser beam for interferometry at the sub-attometer level while operating at continuous wave input power levels ranging from 100 mW to 150 W. These extreme operating conditions required every major component to be custom designed. These designs draw heavily on the experience and understanding gained during the operation of Initial LIGO and Enhanced LIGO. In this article, we report on how the components of the input optics were designed to meet their stringent requirements and present measurements showing how well they have lived up to their design.

  19. The advanced LIGO input optics.

    PubMed

    Mueller, Chris L; Arain, Muzammil A; Ciani, Giacomo; DeRosa, Ryan T; Effler, Anamaria; Feldbaum, David; Frolov, Valery V; Fulda, Paul; Gleason, Joseph; Heintze, Matthew; Kawabe, Keita; King, Eleanor J; Kokeyama, Keiko; Korth, William Z; Martin, Rodica M; Mullavey, Adam; Peold, Jan; Quetschke, Volker; Reitze, David H; Tanner, David B; Vorvick, Cheryl; Williams, Luke F; Mueller, Guido

    2016-01-01

    The advanced LIGO gravitational wave detectors are nearing their design sensitivity and should begin taking meaningful astrophysical data in the fall of 2015. These resonant optical interferometers will have unprecedented sensitivity to the strains caused by passing gravitational waves. The input optics play a significant part in allowing these devices to reach such sensitivities. Residing between the pre-stabilized laser and the main interferometer, the input optics subsystem is tasked with preparing the laser beam for interferometry at the sub-attometer level while operating at continuous wave input power levels ranging from 100 mW to 150 W. These extreme operating conditions required every major component to be custom designed. These designs draw heavily on the experience and understanding gained during the operation of Initial LIGO and Enhanced LIGO. In this article, we report on how the components of the input optics were designed to meet their stringent requirements and present measurements showing how well they have lived up to their design. PMID:26827334

  20. 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.

  1. Design, synthesis, linear and nonlinear photophysical properties and biological imaging application of a novel Λ-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-π-A-π-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.

  2. 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…

  3. 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.

  4. Direct Solvent-Derived Polymer-Coated Nitrogen-Doped Carbon Nanodots with High Water Solubility for Targeted Fluorescence Imaging of Glioma.

    PubMed

    Wang, Yi; Meng, Ying; Wang, Shanshan; Li, Chengyi; Shi, Wei; Chen, Jian; Wang, Jianxin; Huang, Rongqin

    2015-08-01

    Cancer imaging requires biocompatible and bright contrast-agents with selective and high accumulation in the tumor region but low uptake in normal tissues. Herein, 1-methyl-2-pyrrolidinone (NMP)-derived polymer-coated nitrogen-doped carbon nanodots (pN-CNDs) with a particle size in the range of 5-15 nm are prepared by a facile direct solvothermal reaction. The as-prepared pN-CNDs exhibit stable and adjustable fluorescence and excellent water solubility. Results of a cell viability test (CCK-8) and histology analysis both demonstrate that the pN-CNDs have no obvious cytotoxicity. Most importantly, the pN-CNDs can expediently enter glioma cells in vitro and also mediate glioma fluorescence imaging in vivo with good contrast via elevated passive targeting. PMID:25808813

  5. 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.

  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. 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.

  8. 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.

  9. Identifying local and descending inputs for primary sensory neurons.

    PubMed

    Zhang, Yi; Zhao, Shengli; Rodriguez, Erica; Takatoh, Jun; Han, Bao-Xia; Zhou, Xiang; Wang, Fan

    2015-10-01

    Primary pain and touch sensory neurons not only detect internal and external sensory stimuli, but also receive inputs from other neurons. However, the neuronal derived inputs for primary neurons have not been systematically identified. Using a monosynaptic rabies viruses-based transneuronal tracing method combined with sensory-specific Cre-drivers, we found that sensory neurons receive intraganglion, intraspinal, and supraspinal inputs, the latter of which are mainly derived from the rostroventral medulla (RVM). The viral-traced central neurons were largely inhibitory but also consisted of some glutamatergic neurons in the spinal cord and serotonergic neurons in the RVM. The majority of RVM-derived descending inputs were dual GABAergic and enkephalinergic (opioidergic). These inputs projected through the dorsolateral funiculus and primarily innervated layers I, II, and V of the dorsal horn, where pain-sensory afferents terminate. Silencing or activation of the dual GABA/enkephalinergic RVM neurons in adult animals substantially increased or decreased behavioral sensitivity, respectively, to heat and mechanical stimuli. These results are consistent with the fact that both GABA and enkephalin can exert presynaptic inhibition of the sensory afferents. Taken together, this work provides a systematic view of and a set of tools for examining peri- and extrasynaptic regulations of pain-afferent transmission. PMID:26426077

  10. Identifying local and descending inputs for primary sensory neurons

    PubMed Central

    Zhang, Yi; Zhao, Shengli; Rodriguez, Erica; Takatoh, Jun; Han, Bao-Xia; Zhou, Xiang; Wang, Fan

    2015-01-01

    Primary pain and touch sensory neurons not only detect internal and external sensory stimuli, but also receive inputs from other neurons. However, the neuronal derived inputs for primary neurons have not been systematically identified. Using a monosynaptic rabies viruses–based transneuronal tracing method combined with sensory-specific Cre-drivers, we found that sensory neurons receive intraganglion, intraspinal, and supraspinal inputs, the latter of which are mainly derived from the rostroventral medulla (RVM). The viral-traced central neurons were largely inhibitory but also consisted of some glutamatergic neurons in the spinal cord and serotonergic neurons in the RVM. The majority of RVM-derived descending inputs were dual GABAergic and enkephalinergic (opioidergic). These inputs projected through the dorsolateral funiculus and primarily innervated layers I, II, and V of the dorsal horn, where pain-sensory afferents terminate. Silencing or activation of the dual GABA/enkephalinergic RVM neurons in adult animals substantially increased or decreased behavioral sensitivity, respectively, to heat and mechanical stimuli. These results are consistent with the fact that both GABA and enkephalin can exert presynaptic inhibition of the sensory afferents. Taken together, this work provides a systematic view of and a set of tools for examining peri- and extrasynaptic regulations of pain-afferent transmission. PMID:26426077

  11. Images of gravitational and magnetic phenomena derived from two-dimensional back-projection Doppler tomography of interacting binary stars

    SciTech Connect

    Richards, Mercedes T.; Cocking, Alexander S.; Fisher, John G.; Conover, Marshall J. E-mail: asc5097@psu.edu

    2014-11-10

    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 Hα 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.

  12. Magnetic resonance imaging of (1)H long lived states derived from parahydrogen induced polarization in a clinical system.

    PubMed

    Graafen, Dirk; Franzoni, María Belén; Schreiber, Laura M; Spiess, Hans W; Münnemann, Kerstin

    2016-01-01

    Hyperpolarization is a powerful tool to overcome the low sensitivity of nuclear magnetic resonance (NMR). However, applications are limited due to the short lifetime of this non equilibrium spin state caused by relaxation processes. This issue can be addressed by storing hyperpolarization in slowly decaying singlet spin states which was so far mostly demonstrated for non-proton spin pairs, e.g. (13)C-(13)C. Protons hyperpolarized by parahydrogen induced polarization (PHIP) in symmetrical molecules, are very well suited for this strategy because they naturally exhibit a long-lived singlet state. The conversion of the NMR silent singlet spin state to observable magnetization can be achieved by making use of singlet-triplet level anticrossings. In this study, a low-power radiofrequency pulse sequence is used for this purpose, which allows multiple successive singlet-triplet conversions. The generated magnetization is used to record proton images in a clinical magnetic resonance imaging (MRI) system, after 3min waiting time. Our results may open unprecedented opportunities to use the standard MRI nucleus (1)H for e.g. metabolic imaging in the future. PMID:26754064

  13. 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.

  14. Spatial distribution and abundance of red snow algae on the Harding Icefield, Alaska derived from a satellite image

    NASA Astrophysics Data System (ADS)

    Takeuchi, Nozomu; Dial, Roman; Kohshima, Shiro; Segawa, Takahiro; Uetake, Jun

    2006-11-01

    Red snow caused by algal bloom is common on glaciers and snowfields worldwide. Description of spatial distributions of snow algal blooms is important for understanding snow algae's unique life in an extremely cold environment and for determining the effect of algae through the reduction of surface albedo. Here we present the spatial distribution of red snow algae on the Harding Icefield, Alaska retrieved from a satellite image. Field observations on the icefield conducted in August 2001 revealed visible red snow, particularly near the snowline. Field measurements of spectral reflectance on the surface revealed the specific spectral absorption of algal pigments. We found a significant correlation between snow algal biomass and a reflectance ratio of SPOT (Satellite Probatoire d' Observation de la Terre) satellite band of wavelength 610-680 nm to band 500-590 nm. Using this relationship between the reflectance ratio and algal biomass, we estimated the distribution and abundance of red snow across the icefield using a SPOT satellite image. The spatial distribution of red snow on the icefield obtained by mapping the reflectance ratio matched field observations across the icefield with more red algal blooms on the continental than the maritime side of the icefield. Area averaged mean carbon content estimated from the red algal biomass for the icefield on the image was 1.2 kg km-2.

  15. Magnetic resonance imaging of 1H long lived states derived from parahydrogen induced polarization in a clinical system

    NASA Astrophysics Data System (ADS)

    Graafen, Dirk; Franzoni, María Belén; Schreiber, Laura M.; Spiess, Hans W.; Münnemann, Kerstin

    2016-01-01

    Hyperpolarization is a powerful tool to overcome the low sensitivity of nuclear magnetic resonance (NMR). However, applications are limited due to the short lifetime of this non equilibrium spin state caused by relaxation processes. This issue can be addressed by storing hyperpolarization in slowly decaying singlet spin states which was so far mostly demonstrated for non-proton spin pairs, e.g. 13C-13C. Protons hyperpolarized by parahydrogen induced polarization (PHIP) in symmetrical molecules, are very well suited for this strategy because they naturally exhibit a long-lived singlet state. The conversion of the NMR silent singlet spin state to observable magnetization can be achieved by making use of singlet-triplet level anticrossings. In this study, a low-power radiofrequency pulse sequence is used for this purpose, which allows multiple successive singlet-triplet conversions. The generated magnetization is used to record proton images in a clinical magnetic resonance imaging (MRI) system, after 3 min waiting time. Our results may open unprecedented opportunities to use the standard MRI nucleus 1H for e.g. metabolic imaging in the future.

  16. Micro-CT image-derived metrics quantify arterial wall distensibility reduction in a rat model of pulmonary hypertension

    NASA Astrophysics Data System (ADS)

    Johnson, Roger H.; Karau, Kelly L.; Molthen, Robert C.; Haworth, Steven T.; Dawson, Christopher A.

    2000-04-01

    We developed methods to quantify arterial structural and mechanical properties in excised rat lungs and applied them to investigate the distensibility decrease accompanying chronic hypoxia-induced pulmonary hypertension. Lungs of control and hypertensive (three weeks 11% O2) animals were excised and a contrast agent introduced before micro-CT imaging with a special purpose scanner. For each lung, four 3D image data sets were obtained, each at a different intra-arterial contrast agent pressure. Vessel segment diameters and lengths were measured at all levels in the arterial tree hierarchy, and these data used to generate features sensitive to distensibility changes. Results indicate that measurements obtained from 3D micro-CT images can be used to quantify vessel biomechanical properties in this rat model of pulmonary hypertension and that distensibility is reduced by exposure to chronic hypoxia. Mechanical properties can be assessed in a localized fashion and quantified in a spatially-resolved way or as a single parameter describing the tree as a whole. Micro-CT is a nondestructive way to rapidly assess structural and mechanical properties of arteries in small animal organs maintained in a physiological state. Quantitative features measured by this method may provide valuable insights into the mechanisms causing the elevated pressures in pulmonary hypertension of differing etiologies and should become increasingly valuable tools in the study of complex phenotypes in small-animal models of important diseases such as hypertension.

  17. Synthesis and in vitro affinities of various MDL 100907 derivatives as potential 18F-radioligands for 5-HT2A receptor imaging with PET.

    PubMed

    Herth, Matthias M; Kramer, Vasko; Piel, Markus; Palner, Mikael; Riss, Patrick J; Knudsen, Gitte M; Rösch, Frank

    2009-04-15

    Radiolabelled piperidine derivatives such as [(11)C]MDL 100907 and [(18)F]altanserin have played an important role in diagnosing malfunction in the serotonergic neurotransmission. A variety of novel piperidine MDL 100907 derivatives, possible to label with (18)F-fluorine, were synthesized to improve molecular imaging properties of [(11)C]MDL 100907. Their in vitro affinities to a broad spectrum of neuroreceptors and their lipophilicities were determined and compared to the clinically used reference compounds MDL 100907 and altanserin. The novel compounds MA-1 (53) and (R)-MH.MZ (56) show K(i)-values in the nanomolar range towards the 5-HT(2A) receptor and insignificant binding to other 5-HT receptor subtypes or receptors. Interestingly, compounds MA-1 (53), MH.MZ (55) and (R)-MH.MZ (56) provide a receptor selectivity profile similar to MDL 100907. These compounds could possibly be preferable antagonistic (18)F-tracers for visualization of the 5-HT(2A) receptor status. Medium affine compounds (VK-1 (32), (51), (52), (54)) were synthesized and have K(i) values between 30 and 120 nM. All promising compounds show logP values between 2 and 3, that is, within the range of those for the established radiotracers altanserin and MDL 100907. The novel compounds MA-1 (53) and (R)-MH.MZ (56) thus appear to be promising high affine and selective tracers of (18)F-labelled analogues for 5-HT(2A) imaging with PET. PMID:19329329

  18. The IVS data input to ITRF2014

    NASA Astrophysics Data System (ADS)

    Nothnagel, Axel; Alef, Walter; Amagai, Jun; Andersen, Per Helge; Andreeva, Tatiana; Artz, Thomas; Bachmann, Sabine; Barache, Christophe; Baudry, Alain; Bauernfeind, Erhard; Baver, Karen; Beaudoin, Christopher; Behrend, Dirk; Bellanger, Antoine; Berdnikov, Anton; Bergman, Per; Bernhart, Simone; Bertarini, Alessandra; Bianco, Giuseppe; Bielmaier, Ewald; Boboltz, David; Böhm, Johannes; Böhm, Sigrid; Boer, Armin; Bolotin, Sergei; Bougeard, Mireille; Bourda, Geraldine; Buttaccio, Salvo; Cannizzaro, Letizia; Cappallo, Roger; Carlson, Brent; Carter, Merri Sue; Charlot, Patrick; Chen, Chenyu; Chen, Maozheng; Cho, Jungho; Clark, Thomas; Collioud, Arnaud; Colomer, Francisco; Colucci, Giuseppe; Combrinck, Ludwig; Conway, John; Corey, Brian; Curtis, Ronald; Dassing, Reiner; Davis, Maria; de-Vicente, Pablo; Diakov, Alexey; Dickey, John; Diegel, Irv; Doi, Koichiro; Drewes, Hermann; Dube, Maurice; Elgered, Gunnar; Engelhardt, Gerald; Evangelista, Mark; Fan, Qingyuan; Fedotov, Leonid; Fey, Alan; Figueroa, Ricardo; Fukuzaki, Yoshihiro; Gambis, Daniel; Garcia-Espada, Susana; Gaume, Ralph; Gaylard, Michael; Geiger, Nicole; Gipson, John; Gomez, Frank; Gomez-Gonzalez, Jesus; Gordon, David; Govind, Ramesh; Gubanov, Vadim; Gulyaev, Sergei; Haas, Ruediger; Hall, David; Halsig, Sebastian; Hammargren, Roger; Hase, Hayo; Heinkelmann, Robert; Helldner, Leif; Herrera, Cristian; Himwich, Ed; Hobiger, Thomas; Holst, Christoph; Hong, Xiaoyu; Honma, Mareki; Huang, Xinyong; Hugentobler, Urs; Ichikawa, Ryuichi; Iddink, Andreas; Ihde, Johannes; Ilijin, Gennadiy; Ipatov, Alexander; Ipatova, Irina; Ishihara, Misao; Ivanov, D. V.; Jacobs, Chris; Jike, Takaaki; Johansson, Karl-Ake; Johnson, Heidi; Johnston, Kenneth; Ju, Hyunhee; Karasawa, Masao; Kaufmann, Pierre; Kawabata, Ryoji; Kawaguchi, Noriyuki; Kawai, Eiji; Kaydanovsky, Michael; Kharinov, Mikhail; Kobayashi, Hideyuki; Kokado, Kensuke; Kondo, Tetsuro; Korkin, Edward; Koyama, Yasuhiro; Krasna, Hana; Kronschnabl, Gerhard; Kurdubov, Sergey; Kurihara, Shinobu; Kuroda, Jiro; Kwak, Younghee; La Porta, Laura; Labelle, Ruth; Lamb, Doug; Lambert, Sébastien; Langkaas, Line; Lanotte, Roberto; Lavrov, Alexey; Le Bail, Karine; Leek, Judith; Li, Bing; Li, Huihua; Li, Jinling; Liang, Shiguang; Lindqvist, Michael; Liu, Xiang; Loesler, Michael; Long, Jim; Lonsdale, Colin; Lovell, Jim; Lowe, Stephen; Lucena, Antonio; Luzum, Brian; Ma, Chopo; Ma, Jun; Maccaferri, Giuseppe; Machida, Morito; MacMillan, Dan; Madzak, Matthias; Malkin, Zinovy; Manabe, Seiji; Mantovani, Franco; Mardyshkin, Vyacheslav; Marshalov, Dmitry; Mathiassen, Geir; Matsuzaka, Shigeru; McCarthy, Dennis; Melnikov, Alexey; Michailov, Andrey; Miller, Natalia; Mitchell, Donald; Mora-Diaz, Julian Andres; Mueskens, Arno; Mukai, Yasuko; Nanni, Mauro; Natusch, Tim; Negusini, Monia; Neidhardt, Alexander; Nicolson, George; Niell, Arthur; Nikitin, Pavel; Nilsson, Tobias; Ning, Tong; Nishikawa, Takashi; Noll, Carey; Nozawa, Kentarou; Ogaja, Clement; Oh, Hongjong; Olofsson, Hans; Opseth, Per Erik; Orfei, Sandro; Pacione, Rosa; Pazamickas, Katherine; Petrachenko, William; Pettersson, Lars; Pino, Pedro; Plank, Lucia; Ploetz, Christian; Poirier, Michael; Poutanen, Markku; Qian, Zhihan; Quick, Jonathan; Rahimov, Ismail; Redmond, Jay; Reid, Brett; Reynolds, John; Richter, Bernd; Rioja, Maria; Romero-Wolf, Andres; Ruszczyk, Chester; Salnikov, Alexander; Sarti, Pierguido; Schatz, Raimund; Scherneck, Hans-Georg; Schiavone, Francesco; Schreiber, Ulrich; Schuh, Harald; Schwarz, Walter; Sciarretta, Cecilia; Searle, Anthony; Sekido, Mamoru; Seitz, Manuela; Shao, Minghui; Shibuya, Kazuo; Shu, Fengchun; Sieber, Moritz; Skjaeveland, Asmund; Skurikhina, Elena; Smolentsev, Sergey; Smythe, Dan; Sousa, Don; Sovers, Ojars; Stanford, Laura; Stanghellini, Carlo; Steppe, Alan; Strand, Rich; Sun, Jing; Surkis, Igor; Takashima, Kazuhiro; Takefuji, Kazuhiro; Takiguchi, Hiroshi; Tamura, Yoshiaki; Tanabe, Tadashi; Tanir, Emine; Tao, An; Tateyama, Claudio; Teke, Kamil; Thomas, Cynthia; Thorandt, Volkmar; Thornton, Bruce; Tierno Ros, Claudia; Titov, Oleg; Titus, Mike; Tomasi, Paolo; Tornatore, Vincenza; Trigilio, Corrado; Trofimov, Dmitriy; Tsutsumi, Masanori; Tuccari, Gino; Tzioumis, Tasso; Ujihara, Hideki; Ullrich, Dieter; Uunila, Minttu; Venturi, Tiziana; Vespe, Francesco; Vityazev, Veniamin; Volvach, Alexandr; Vytnov, Alexander; Wang, Guangli; Wang, Jinqing; Wang, Lingling; Wang, Na; Wang, Shiqiang; Wei, Wenren; Weston, Stuart; Whitney, Alan; Wojdziak, Reiner; Yatskiv, Yaroslav; Yang, Wenjun; Ye, Shuhua; Yi, Sangoh; Yusup, Aili; Zapata, Octavio; Zeitlhoefler, Reinhard; Zhang, Hua; Zhang, Ming; Zhang, Xiuzhong; Zhao, Rongbing; Zheng, Weimin; Zhou, Ruixian; Zubko, Nataliya

    2015-01-01

    Very Long Baseline Interferometry (VLBI) is a primary space-geodetic technique for determining precise coordinates on the Earth, for monitoring the variable Earth rotation and orientation with highest precision, and for deriving many other parameters of the Earth system. The International VLBI Service for Geodesy and Astrometry (IVS, http://ivscc.gsfc.nasa.gov/) is a service of the International Association of Geodesy (IAG) and the International Astronomical Union (IAU). The datasets published here are the results of individual Very Long Baseline Interferometry (VLBI) sessions in the form of normal equations in SINEX 2.0 format (http://www.iers.org/IERS/EN/Organization/AnalysisCoordinator/SinexFormat/sinex.html, the SINEX 2.0 description is attached as pdf) provided by IVS as the input for the next release of the International Terrestrial Reference System (ITRF): ITRF2014. This is a new version of the ITRF2008 release (Bockmann et al., 2009). For each session/ file, the normal equation systems contain elements for the coordinate components of all stations having participated in the respective session as well as for the Earth orientation parameters (x-pole, y-pole, UT1 and its time derivatives plus offset to the IAU2006 precession-nutation components dX, dY (https://www.iau.org/static/resolutions/IAU2006_Resol1.pdf). The terrestrial part is free of datum. The data sets are the result of a weighted combination of the input of several IVS Analysis Centers. The IVS contribution for ITRF2014 is described in Bachmann et al (2015), Schuh and Behrend (2012) provide a general overview on the VLBI method, details on the internal data handling can be found at Behrend (2013).

  19. 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.

  20. Inputs for subject-specific computational fluid dynamics simulation of blood flow in the mouse aorta.

    PubMed

    Van Doormaal, Mark; Zhou, Yu-Qing; Zhang, Xiaoli; Steinman, David A; Mark Henkelman, R

    2014-10-01

    Mouse models are an important way for exploring relationships between blood hemodynamics and eventual plaque formation. We have developed a mouse model of aortic regurgitation (AR) that produces large changes in plaque burden with charges in hemodynamics [Zhou et al., 2010, "Aortic Regurgitation Dramatically Alters the Distribution of Atherosclerotic Lesions and Enhances Atherogenesis in Mice," Arterioscler. Thromb. Vasc. Biol., 30(6), pp. 1181-1188]. In this paper, we explore the amount of detail needed for realistic computational fluid dynamics (CFD) calculations in this experimental model. The CFD calculations use inputs based on experimental measurements from ultrasound (US), micro computed tomography (CT), and both anatomical magnetic resonance imaging (MRI) and phase contrast MRI (PC-MRI). The adequacy of five different levels of model complexity (a) subject-specific CT data from a single mouse; (b) subject-specific CT centerlines with radii from US; (c) same as (b) but with MRI derived centerlines; (d) average CT centerlines and averaged vessel radius and branching vessels; and (e) same as (d) but with averaged MRI centerlines) is evaluated by demonstrating their impact on relative residence time (RRT) outputs. The paper concludes by demonstrating the necessity of subject-specific geometry and recommends for inputs the use of CT or anatomical MRI for establishing the aortic centerlines, M-mode US for scaling the aortic diameters, and a combination of PC-MRI and Doppler US for estimating the spatial and temporal characteristics of the input wave forms. PMID:25070260

  1. Deriving urban dynamic evolution rules from self-adaptive cellular automata with multi-temporal remote sensing images

    NASA Astrophysics Data System (ADS)

    He, Yingqing; Ai, Bin; Yao, Yao; Zhong, Fajun

    2015-06-01

    Cellular automata (CA) have proven to be very effective for simulating and predicting the spatio-temporal evolution of complex geographical phenomena. Traditional methods generally pose problems in determining the structure and parameters of CA for a large, complex region or a long-term simulation. This study presents a self-adaptive CA model integrated with an artificial immune system to discover dynamic transition rules automatically. The model's parameters are allowed to be self-modified with the application of multi-temporal remote sensing images: that is, the CA can adapt itself to the changed and complex environment. Therefore, urban dynamic evolution rules over time can be efficiently retrieved by using this integrated model. The proposed AIS-based CA model was then used to simulate the rural-urban land conversion of Guangzhou city, located in the core of China's Pearl River Delta. The initial urban land was directly classified from TM satellite image in the year 1990. Urban land in the years 1995, 2000, 2005, 2009 and 2012 was correspondingly used as the observed data to calibrate the model's parameters. With the quantitative index figure of merit (FoM) and pattern similarity, the comparison was further performed between the AIS-based model and a Logistic CA model. The results indicate that the AIS-based CA model can perform better and with higher precision in simulating urban evolution, and the simulated spatial pattern is closer to the actual development situation.

  2. Labeling of cynomolgus monkey bone marrow-derived mesenchymal stem cells for cell tracking by multimodality imaging.

    PubMed

    Ren, ZhenHua; Wang, JiaYin; Zou, ChunLin; Guan, YunQian; Zhang, Yu Alex

    2011-11-01

    Recently, transplantation of allogeneic and autologous cells has been used for regenerative medicine. A critical issue is monitoring migration and homing of transplanted cells, as well as engraftment efficiency and functional capability in vivo. Monitoring of superparamagnetic iron oxide (SPIO) particles by magnetic resonance imaging (MRI) has been used in animal models and clinical settings to track labeled cells. A major limitation of MRI is that the signals do not show biological characteristics of transplanted cells in vivo. Bone marrow mesenchymal stem cells (MSCs) have been extensively investigated for their various therapeutic properties, and exhibit the potential to differentiate into cells of diverse lineages. In this study, cynomolgus monkey MSCs (cMSCs) were labeled with Molday ION Rhodamine-B™ (MIRB), a new SPIO agent, to investigate and characterize the biophysical and MRI properties of labeled cMSCs in vitro and in vivo. The results indicate that MIRB is biocompatible and useful for cMSCs labeling and cell tracking by multimodality imaging. Our method is helpful for detection of transplanted stem cells in vivo, which is required for understanding mechanisms of cell therapy. PMID:22173303

  3. Mitochondria-targeted Triphenylamine Derivatives Activatable by Two-Photon Excitation for Triggering and Imaging Cell Apoptosis.

    PubMed

    Chennoufi, Rahima; Bougherara, Houcine; Gagey-Eilstein, Nathalie; Dumat, Blaise; Henry, Etienne; Subra, Frédéric; Bury-Moné, Stéphanie; Mahuteau-Betzer, Florence; Tauc, Patrick; Teulade-Fichou, Marie-Paule; Deprez, Eric

    2016-01-01

    Photodynamic therapy (PDT) leads to cell death by using a combination of a photosensitizer and an external light source for the production of lethal doses of reactive oxygen species (ROS). Since a major limitation of PDT is the poor penetration of UV-visible light in tissues, there is a strong need for organic compounds whose activation is compatible with near-infrared excitation. Triphenylamines (TPAs) are fluorescent compounds, recently shown to efficiently trigger cell death upon visible light irradiation (458 nm), however outside the so-called optical/therapeutic window. Here, we report that TPAs target cytosolic organelles of living cells, mainly mitochondria, triggering a fast apoptosis upon two-photon excitation, thanks to their large two-photon absorption cross-sections in the 760-860 nm range. Direct ROS imaging in the cell context upon multiphoton excitation of TPA and three-color flow cytometric analysis showing phosphatidylserine externalization indicate that TPA photoactivation is primarily related to the mitochondrial apoptotic pathway via ROS production, although significant differences in the time courses of cell death-related events were observed, depending on the compound. TPAs represent a new class of water-soluble organic photosensitizers compatible with direct two-photon excitation, enabling simultaneous multiphoton fluorescence imaging of cell death since a concomitant subcellular TPA re-distribution occurs in apoptotic cells. PMID:26947258

  4. Mitochondria-targeted Triphenylamine Derivatives Activatable by Two-Photon Excitation for Triggering and Imaging Cell Apoptosis

    PubMed Central

    Chennoufi, Rahima; Bougherara, Houcine; Gagey-Eilstein, Nathalie; Dumat, Blaise; Henry, Etienne; Subra, Frédéric; Bury-Moné, Stéphanie; Mahuteau-Betzer, Florence; Tauc, Patrick; Teulade-Fichou, Marie-Paule; Deprez, Eric

    2016-01-01

    Photodynamic therapy (PDT) leads to cell death by using a combination of a photosensitizer and an external light source for the production of lethal doses of reactive oxygen species (ROS). Since a major limitation of PDT is the poor penetration of UV-visible light in tissues, there is a strong need for organic compounds whose activation is compatible with near-infrared excitation. Triphenylamines (TPAs) are fluorescent compounds, recently shown to efficiently trigger cell death upon visible light irradiation (458 nm), however outside the so-called optical/therapeutic window. Here, we report that TPAs target cytosolic organelles of living cells, mainly mitochondria, triggering a fast apoptosis upon two-photon excitation, thanks to their large two-photon absorption cross-sections in the 760–860 nm range. Direct ROS imaging in the cell context upon multiphoton excitation of TPA and three-color flow cytometric analysis showing phosphatidylserine externalization indicate that TPA photoactivation is primarily related to the mitochondrial apoptotic pathway via ROS production, although significant differences in the time courses of cell death-related events were observed, depending on the compound. TPAs represent a new class of water-soluble organic photosensitizers compatible with direct two-photon excitation, enabling simultaneous multiphoton fluorescence imaging of cell death since a concomitant subcellular TPA re-distribution occurs in apoptotic cells. PMID:26947258

  5. 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

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

    PubMed Central

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

    2014-01-01

    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

  7. Evaluation of the Iron(iii) Complex of the 3,5 - Derivative of Catechol as AN Organ-Selective Magnetic Resonance Imaging Contrast Agent.

    NASA Astrophysics Data System (ADS)

    Sayed, M. Gary

    The iron (III) diethylsulfonamide derivative of catechol (Fe(III)-DESAC) is a new target selective magnetic resonance imaging contrast agent based on the second-sphere interaction mechanism. It is a highly stable tris-complex that was chemically characterized for potential use as a magnetopharmaceutical. The contrast agent was evaluated for gross toxicity and biodistribution in a Fisher 344 rat model. The agent showed no significant acute toxicity at low doses. At a higher dose, 0.15 mmol/kg, the contrast agent exhibited toxic effects in test animals. No signs of abnormal behavior or chronic toxicity was noted. Biodistribution studies revealed increased uptake by the liver parenchyma and the kidneys suggesting combined hepatobiliary and renal excretion. Its potential as a magnetopharmaceutical was evaluated using a GE Signa MRI scanner at 0.1 mmol/kg doses in phantom and an animal model. Relaxivity measurements resulted in R_1 and R_2 relaxivity values of 2.47 mM^{ -1} sec^{-1} and 3.16 mM^{-1} sec ^{-1}, respectively. T _1-weighted MR images showed 63% increase in the liver image values and 99% increase in the kidney values. This contrast enhancement was approximately 75% greater in the healthy parenchyma compared to the imbedded mammary adenocarcinoma.

  8. Image

    Energy Science and Technology Software Center (ESTSC)

    2007-08-31

    The computer side of the IMAGE project consists of a collection of Perl scripts that perform a variety of tasks; scripts are available to insert, update and delete data from the underlying Oracle database, download data from NCBI's Genbank and other sources, and generate data files for download by interested parties. Web scripts make up the tracking interface, and various tools available on the project web-site (image.llnl.gov) that provide a search interface to the database.

  9. 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.

  10. 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.

  11. 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.

  12. Fuzzy ARTMAP with input relevances.

    PubMed

    Andonie, Răzvan; Sasu, Lucian

    2006-07-01

    We introduce a new fuzzy ARTMAP (FAM) neural network: Fuzzy ARTMAP with relevance factor (FAMR). The FAMR architecture is able to incrementally "grow" and to sequentially accommodate input-output sample pairs. Each training pair has a relevance factor assigned to it, proportional to the importance of that pair during the learning phase. The relevance factors are user-defined or computed. The FAMR can be trained as a classifier and, at the same time, as a nonparametric estimator of the probability that an input belongs to a given class. The FAMR probability estimation converges almost surely and in the mean square to the posterior probability. Our theoretical results also characterize the convergence rate of the approximation. Using a relevance factor adds more flexibility to the training phase, allowing ranking of sample pairs according to the confidence we have in the information source. We analyze the FAMR capability for mapping noisy functions when training data originates from multiple sources with known levels of noise. PMID:16856656

  13. Dendritic Organization of Olfactory Inputs to Medial Amygdala Neurons.

    PubMed

    Keshavarzi, Sepideh; Power, John M; Albers, Eva H H; Sullivan, Robert K S; Sah, Pankaj

    2015-09-23

    The medial amygdala (MeA) is a central hub in the olfactory neural network. It receives vomeronasal information directly from the accessory olfactory bulb (AOB) and main olfactory information largely via odor-processing regions such as the olfactory cortical amygdala (CoA). How these inputs are processed by MeA neurons is poorly understood. Using the GAD67-GFP mouse, we show that MeA principal neurons receive convergent AOB and CoA inputs. Somatically recorded AOB synaptic inputs had slower kinetics than CoA inputs, suggesting that they are electrotonically more distant. Field potential recording, pharmacological manipulation, and Ca(2+) imaging revealed that AOB synapses are confined to distal dendrites and segregated from the proximally located CoA synapses. Moreover, unsynchronized AOB inputs had significantly broader temporal summation that was dependent on the activation of NMDA receptors. These findings show that MeA principal neurons process main and accessory olfactory inputs differentially in distinct dendritic compartments. Significance statement: In most vertebrates, olfactory cues are processed by two largely segregated neural pathways, the main and accessory olfactory systems, which are specialized to detect odors and nonvolatile chemosignals, respectively. Information from these two pathways ultimately converges at higher brain regions, one of the major hubs being the medial amygdala. Little is known about how olfactory inputs are processed by medial amygdala neurons. This study shows that individual principal neurons in this region receive input from both pathways and that these synapses are spatially segregated on their dendritic tree. We provide evidence suggesting that this dendritic segregation leads to distinct input integration and impact on neuronal output; hence, dendritic mechanisms control olfactory processing in the amygdala. PMID:26400933

  14. Synthesis and evaluation of a radioiodinated 4,6-diaryl-3-cyano-2-pyridinone derivative as a survivin targeting SPECT probe for tumor imaging.

    PubMed

    Fuchigami, Takeshi; Mizoguchi, Tatsuya; Ishikawa, Natsumi; Haratake, Mamoru; Yoshida, Sakura; Magata, Yasuhiro; Nakayama, Morio

    2016-02-01

    Survivin is overexpressed in most of the cancerous tissues but not in terminally differentiated normal tissues, making it an attractive target for diagnosis and therapy of various types of cancers. In this study, we aimed to develop 4,6-diaryl-3-cyano-2-pyridinone (DCP) derivatives, as novel cancer imaging probes that target survivin. Chloro and iodo analogs of DCP (CDCP and IDCP, respectively) were successfully synthesized by using a previously unreported carbon monoxide-free procedure. IDCP exhibited a slightly higher binding affinity for recombinant human survivin (Kd=34nM) than that of CDCP (Kd=44nM). Fluorescence staining indicated that both CDCP and IDCP showed high signals in MDA-MB-231 cells with high levels of survivin expression. Significantly low fluorescent signals were observed in MCF-10A cells, which showed low levels of survivin expression. [(125)I]IDCP was synthesized for the application of IDCP to single photon emission computed tomography (SPECT) imaging. Quantitative in vitro binding of [(125)I]IDCP in cell cultures showed results consistent to those observed after fluorescent staining. In vivo biodistribution studies in tumor-bearing mice demonstrated that the tumor uptake of [(125)I]IDCP increased gradually with time and was 0.65% injected dose per gram (% ID/g) at 180min. The maximum tumor/blood and tumor/muscle ratio at 60min were 0.87 and 2.27, respectively, indicating inadequate [(125)I]IDCP accumulation in tumors necessary for in vivo imaging. Although further structural modifications are necessary to improve pharmacokinetic properties of IDCP, this study demonstrates the feasibility of using the DCP backbone as a scaffold for the development of survivin-targeting tumor imaging probes. PMID:26733475

  15. Observation of WINDII polar hemispheric spiral patterns in wind and emission rate as a measure of energy input to the ionosphere-atmosphere system

    NASA Astrophysics Data System (ADS)

    Shepherd, G. G.; Cho, Y.

    2013-12-01

    Polar hemispheric images of the atomic oxygen O1S green line 557.7 nm thermospheric dayglow emission and winds derived from that emission provide a measure of energy input from the magnetosphere, delivered through the aurora to the ionosphere-thermosphere system. These images, provided by the WINDII (WIND Imaging Interferometer) instrument, operated on NASA's UARS (Upper Atmosphere Research Satellite) from 1991 to 2003, are spatio-temporal patterns obtained during a single day, a composite of data from all orbits for that day. These images regularly reveal spiral patterns, originating in the auroral region and extending to the equator. This dayglow emission, obtained from 250 km altitude, is normally dominated by photoelectron impact on atomic oxygen, but model results indicate that the spiral enhancements are the result of the dissociative recombination of O2+, which along with other evidence suggests a relationship to TIDs (Travelling Ionospheric Disturbances); the wind observations support that interpretation. Direct observation confirming the emission ionospheric source is sought. Nighttime images show very weak emission that can only be produced by the dissociative recombination source. A clue to the dominant daytime source may be the Doppler temperature of the green line emission, which would be hot (non-thermal) for dissociative recombination. In this presentation, an earlier case study for a single day is extended to a series of days corresponding to a wide range of energy input with the objective of relating that input to the observed characteristics of these daily emission rate and wind spiral patterns.

  16. 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.

  17. Power spectra of the natural input to the visual system.

    PubMed

    Pamplona, D; Triesch, J; Rothkopf, C A

    2013-05-01

    The efficient coding hypothesis posits that sensory systems are adapted to the regularities of their signal input so as to reduce redundancy in the resulting representations. It is therefore important to characterize the regularities of natural signals to gain insight into the processing of natural stimuli. While measurements of statistical regularity in vision have focused on photographic images of natural environments it has been much less investigated, how the specific imaging process embodied by the organism's eye induces statistical dependencies on the natural input to the visual system. This has allowed using the convenient assumption that natural image data are homogeneous across the visual field. Here we give up on this assumption and show how the imaging process in a human model eye influences the local statistics of the natural input to the visual system across the entire visual field. Artificial scenes with three-dimensional edge elements were generated and the influence of the imaging projection onto the back of a spherical model eye were quantified. These distributions show a strong radial influence of the imaging process on the resulting edge statistics with increasing eccentricity from the model fovea. This influence is further quantified through computation of the second order intensity statistics as a function of eccentricity from the center of projection using samples from the dead leaves image model. Using data from a naturalistic virtual environment, which allows generation of correctly projected images onto the model eye across the entire field of view, we quantified the second order dependencies as function of the position in the visual field using a new generalized parameterization of the power spectra. Finally, we compared this analysis with a commonly used natural image database, the van Hateren database, and show good agreement within the small field of view available in these photographic images. We conclude by providing a detailed quantitative analysis of the second order statistical dependencies of the natural input to the visual system across the visual field and demonstrating the importance of considering the influence of the sensory system on the statistical regularities of the input to the visual system. PMID:23458676

  18. Multiple input electrode gap controller

    DOEpatents

    Hysinger, Christopher L.; Beaman, Joseph J.; Melgaard, David K.; Williamson, Rodney L.

    1999-01-01

    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.

  19. 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.

  20. Single Particle Dynamic Imaging and Fe(3+) Sensing with Bright Carbon Dots Derived from Bovine Serum Albumin Proteins.

    PubMed

    Yang, Qingxiu; Wei, Lin; Zheng, Xuanfang; Xiao, Lehui

    2015-01-01

    In this work, we demonstrated a convenient and green strategy for the synthesis of highly luminescent and water-soluble carbon dots (Cdots) by carbonizing carbon precursors, i.e., Bovine serum albumin (BSA) nanoparticles, in water solution. Without post surface modification, the as-synthesized Cdots exhibit fluorescence quantum yield (Q.Y.) as high as 34.8% and display superior colloidal stability not only in concentrated salt solutions (e.g. 2 M KCl) but also in a wide range of pH solutions. According to the FT-IR measurements, the Cdots contain many carboxyl groups, providing a versatile route for further chemical and biological functionalization. Through conjugation of Cdots with the transacting activator of transcription (TAT) peptide (a kind of cell penetration peptide (CPP)) derived from human immunodeficiency virus (HIV), it is possible to directly monitor the dynamic interactions of CPP with living cell membrane at single particle level. Furthermore, these Cdots also exhibit a dosage-dependent selectivity toward Fe(3+) among other metal ions, including K(+), Na(+), Mg(2+), Hg(2+), Co(2+), Cu(2+), Pb(2+) and Al(3+). We believed that the Cdots prepared by this strategy would display promising applications in various areas, including analytical chemistry, nanomedicine, biochemistry and so on. PMID:26634992

  1. Single Particle Dynamic Imaging and Fe3+ Sensing with Bright Carbon Dots Derived from Bovine Serum Albumin Proteins

    NASA Astrophysics Data System (ADS)

    Yang, Qingxiu; Wei, Lin; Zheng, Xuanfang; Xiao, Lehui

    2015-12-01

    In this work, we demonstrated a convenient and green strategy for the synthesis of highly luminescent and water-soluble carbon dots (Cdots) by carbonizing carbon precursors, i.e., Bovine serum albumin (BSA) nanoparticles, in water solution. Without post surface modification, the as-synthesized Cdots exhibit fluorescence quantum yield (Q.Y.) as high as 34.8% and display superior colloidal stability not only in concentrated salt solutions (e.g. 2 M KCl) but also in a wide range of pH solutions. According to the FT-IR measurements, the Cdots contain many carboxyl groups, providing a versatile route for further chemical and biological functionalization. Through conjugation of Cdots with the transacting activator of transcription (TAT) peptide (a kind of cell penetration peptide (CPP)) derived from human immunodeficiency virus (HIV), it is possible to directly monitor the dynamic interactions of CPP with living cell membrane at single particle level. Furthermore, these Cdots also exhibit a dosage-dependent selectivity toward Fe3+ among other metal ions, including K+, Na+, Mg2+, Hg2+, Co2+, Cu2+, Pb2+ and Al3+. We believed that the Cdots prepared by this strategy would display promising applications in various areas, including analytical chemistry, nanomedicine, biochemistry and so on.

  2. The influence on sarcopenia of muscle quality and quantity derived from magnetic resonance imaging and neuromuscular properties.

    PubMed

    Power, Geoffrey A; Allen, Matti D; Booth, William J; Thompson, R Terry; Marsh, Greg D; Rice, Charles L

    2014-06-01

    The relative contributions of intrinsic and extrinsic neuromuscular factors on sarcopenia are poorly understood. The associations among age-related declines of strength, muscle mass, and muscle quality in response to motor unit (MU) loss have not been systematically investigated in the same groups of subjects. The purpose was to assess MU loss, MRI-derived muscle cross-sectional area (CSA), muscle protein quantity (MPQ), and normalized strength of the dorsiflexors in one group of young (~25 years) adult males compared with two groups of healthy men aged 60–85 years. Muscle strength was assessed on a dynamometer and was ~25 % lower in both older groups, but CSA was less only in the older (>75 years) men, with no differences between the young and old (60–73 years). Normalized strength tended to be lower in both groups of aged men compared to young. For MPQ, only the older men showed ~8 % lower values than the young and old men. Older men had fewer functioning MUs than old, and both groups of aged men had fewer MUs than young men. Muscle quality appears to be maintained in the old likely due to compensatory MU remodeling, but in the older group (>75 years), MU loss was higher and MPQ was lower. PMID:24658708

  3. Single Particle Dynamic Imaging and Fe3+ Sensing with Bright Carbon Dots Derived from Bovine Serum Albumin Proteins

    PubMed Central

    Yang, Qingxiu; Wei, Lin; Zheng, Xuanfang; Xiao, Lehui

    2015-01-01

    In this work, we demonstrated a convenient and green strategy for the synthesis of highly luminescent and water-soluble carbon dots (Cdots) by carbonizing carbon precursors, i.e., Bovine serum albumin (BSA) nanoparticles, in water solution. Without post surface modification, the as-synthesized Cdots exhibit fluorescence quantum yield (Q.Y.) as high as 34.8% and display superior colloidal stability not only in concentrated salt solutions (e.g. 2 M KCl) but also in a wide range of pH solutions. According to the FT-IR measurements, the Cdots contain many carboxyl groups, providing a versatile route for further chemical and biological functionalization. Through conjugation of Cdots with the transacting activator of transcription (TAT) peptide (a kind of cell penetration peptide (CPP)) derived from human immunodeficiency virus (HIV), it is possible to directly monitor the dynamic interactions of CPP with living cell membrane at single particle level. Furthermore, these Cdots also exhibit a dosage-dependent selectivity toward Fe3+ among other metal ions, including K+, Na+, Mg2+, Hg2+, Co2+, Cu2+, Pb2+ and Al3+. We believed that the Cdots prepared by this strategy would display promising applications in various areas, including analytical chemistry, nanomedicine, biochemistry and so on. PMID:26634992

  4. Live Cell Imaging During Germination Reveals Dynamic Tubular Structures Derived from Protein Storage Vacuoles of Barley Aleurone Cells

    PubMed Central

    Ibl, Verena; Stoger, Eva

    2014-01-01

    The germination of cereal seeds is a rapid developmental process in which the endomembrane system undergoes a series of dynamic morphological changes to mobilize storage compounds. The changing ultrastructure of protein storage vacuoles (PSVs) in the cells of the aleurone layer has been investigated in the past, but generally this involved inferences drawn from static pictures representing different developmental stages. We used live cell imaging in transgenic barley plants expressing a TIP3-GFP fusion protein as a fluorescent PSV marker to follow in real time the spatially and temporally regulated remodeling and reshaping of PSVs during germination. During late-stage germination, we observed thin, tubular structures extending from PSVs in an actin-dependent manner. No extensions were detected following the disruption of actin microfilaments, while microtubules did not appear to be involved in the process. The previously-undetected tubular PSV structures were characterized by complex movements, fusion events and a dynamic morphology. Their function during germination remains unknown, but might be related to the transport of solutes and metabolites. PMID:27135513

  5. Representations of modality-specific affective processing for visual and auditory stimuli derived from functional magnetic resonance imaging data.

    PubMed

    Shinkareva, Svetlana V; Wang, Jing; Kim, Jongwan; Facciani, Matthew J; Baucom, Laura B; Wedell, Douglas H

    2014-07-01

    There is converging evidence that people rapidly and automatically encode affective dimensions of objects, events, and environments that they encounter in the normal course of their daily routines. An important research question is whether affective representations differ with sensory modality. This research examined the nature of the dependency of affect and sensory modality at a whole-brain level of analysis in an incidental affective processing paradigm. Participants were presented with picture and sound stimuli that differed in positive or negative valence in an event-related functional magnetic resonance imaging experiment. Global statistical tests, applied at a level of the individual, demonstrated significant sensitivity to valence within modality, but not valence across modalities. Modality-general and modality-specific valence hypotheses predict distinctly different multidimensional patterns of the stimulus conditions. Examination of lower dimensional representation of the data demonstrated separable dimensions for valence processing within each modality. These results provide support for modality-specific valence processing in an incidental affective processing paradigm at a whole-brain level of analysis. Future research should further investigate how stimulus-specific emotional decoding may be mediated by the physical properties of the stimuli. PMID:24302696

  6. Activatable fluorescent cys-diabody conjugated with indocyanine green derivative: consideration of fluorescent catabolite kinetics on molecular imaging

    PubMed Central

    Sano, Kohei; Nakajima, Takahito; Ali, Towhid; Bartlett, Derek W.; Wu, Anna M.; Kim, Insook; Paik, Chang H.; Choyke, Peter L.

    2013-01-01

    Abstract. Antibody fragments including diabodies have more desirable pharmacokinetic characteristics than whole antibodies. An activatable optical imaging probe based on a cys-diabody targeting prostate-specific membrane antigen conjugated with the near-infrared fluorophore, indocyanine green (ICG), was designed such that it can only be activated when bound to the tumor, leading to high signal-to-background ratios. We employed short polyethylene glycol (PEG) linkers between the ICG and the reactive functional group (Sulfo-OSu group), resulting in covalent conjugation of ICG to the cys-diabody, which led to lower dissociation of ICG from cys-diabody early after injection, reducing hepatic uptake. However, unexpectedly, high and long-term fluorescence was observed in the kidneys, liver, and blood pool more than 1 h after injection of the cys-diabody PEG-ICG conjugate. A biodistribution study using I125-labeled cys-diabody-ICG showed immediate uptake in the kidneys followed by a rapid decrease, while gastric activity increased due to released radioiodine during rapid cys-diabody-ICG catabolism in the kidneys. To avoid this catabolic pathway, it would be preferable to use antibody fragments large enough not to be filtered through glomerulus or to conjugate the fragments with fluorescent dyes that are readily excreted into urine when cleaved from the cys-diabody to achieve high tumor-specific detection. PMID:23752742

  7. Rational design of a fluorescent NADPH derivative imaging constitutive nitric-oxide synthases upon two-photon excitation.

    PubMed

    Li, Yun; Wang, Huan; Tarus, Bogdan; Perez, Miguel Romero; Morellato, Laurence; Henry, Etienne; Berka, Vladimir; Tsai, Ah-Lim; Ramassamy, Booma; Dhimane, Hamid; Dessy, Chantal; Tauc, Patrick; Boucher, Jean-Luc; Deprez, Eric; Slama-Schwok, Anny

    2012-07-31

    We report the structure-based design and synthesis of a unique NOS inhibitor, called nanoshutter NS1, with two-photon absorption properties. NS1 targets the NADPH site of NOS by a nucleotide moiety mimicking NADPH linked to a conjugated push-pull chromophore with nonlinear absorption properties. Because NS1 could not provide reducing equivalents to the protein and competed with NADPH binding, it efficiently inhibited NOS catalysis. NS1 became fluorescent once bound to NOS with an excellent signal-to-noise ratio because of two-photon excitation avoiding interference from the flavin-autofluorescence and because free NS1 was not fluorescent in aqueous solutions. NS1 fluorescence enhancement was selective for constitutive NOS in vitro, in particular for endothelial NOS (eNOS). Molecular dynamics simulations suggested that two variable residues among NOS isoforms induced differences in binding of NS1 and in local solvation around NS1 nitro group, consistent with changes of NS1 fluorescence yield. NS1 colocalized with eNOS in living human umbilical vein endothelial cells. Thus, NS1 constitutes a unique class of eNOS probe with two-photon excitation in the 800-950-nm range, with great perspectives for eNOS imaging in living tissues. PMID:22802674

  8. Retrospective analysis of outcomes after IVF using an aneuploidy risk model derived from time-lapse imaging without PGS.

    PubMed

    Campbell, Alison; Fishel, Simon; Bowman, Natalie; Duffy, Samantha; Sedler, Mark; Thornton, Simon

    2013-08-01

    Time-lapse imaging of human preimplantation IVF embryos has enabled objective algorithms based on novel observations of development (morphokinetics) to be used for clinical selection of embryos. Embryo aneuploidy, a major cause of IVF failure, has been correlated with specific morphokinetic variables used previously to develop an aneuploidy risk classification model. The purpose of this study was to evaluate the effectiveness and potential impact of this model for unselected IVF patients without biopsy and preimplantation genetic screening (PGS). Embryo outcomes - no implantation, fetal heart beat (FHB) and live birth (LB) - of 88 transferred blastocysts were compared according to calculated aneuploidy risk classes (low, medium, high). A significant difference was seen for FHB (P<0.0001) and LB (P<0.01) rates between embryos classified as low and medium risk. Within the low-risk class, relative increases of 74% and 56%, compared with rates for all blastocysts, were observed for FHB and LB respectively. The area under the receiver operating characteristic curve was 0.75 for FHB and 0.74 for LB. This study demonstrates the clinical relevance of the aneuploidy risk classification model and introduces a novel, non-invasive method of embryo selection to yield higher implantation and live birth rates without PGS. PMID:23683847

  9. Hemodynamic assessment of partial mechanical circulatory support: data derived from computed tomography angiographic images and computational fluid dynamics

    PubMed Central

    Karmonik, Christof; Rengier, Fabian; Meredig, Hagen; Farag, Mina Berty; Müller-Eschner, Matthias; Arif, Rawa; Popov, Aron-Frederik; Kauczor, Hans-Ulrich; Karck, Matthias; Ruhparwar, Arjang

    2015-01-01

    Partial mechanical circulatory support represents a new concept for the treatment of advanced heart failure. The Circulite Synergy Micro Pump®, where the inflow cannula is connected to the left atrium and the outflow cannula to the right subclavian artery, was one of the first devices to introduce this concept to the clinic. Using computational fluid dynamics (CFD) simulations, hemodynamics in the aortic tree was visualized and quantified from computed tomography angiographic (CTA) images in two patients. A realistic computational model was created by integrating flow information from the native heart and from the Circulite device. Diastolic flow augmentation in the descending aorta but competing/antagonizing flow patterns in the proximal innominate artery was observed. Velocity time curves in the ascending aorta correlated well with those in the left common carotid, the left subclavian and the descending aorta but poorly with the one in the innominate. Our results demonstrate that CFD may be useful in providing a better understanding of the main flow patterns in mechanical circulatory support devices. PMID:25984458

  10. Laser scanning graphic input system

    NASA Astrophysics Data System (ADS)

    Junkins, John L.; Gadhok, Jagmohan S.

    1993-12-01

    A novel method for digitization of hand-written and hand-drawn information is presented. Two or more resonant laser scanners sweep out a plane, the interruption of these laser beams by a hand-held stylus and the beams' angular positions are detected. These data can be used to digitize coordinates along the hand-drawn lines with high precision (approximately 1 part in 10,000) and digitization rates (> 150 HZ). The data input surface can vary from small to large (permitting digitization on wall-sized writing surfaces), thus enabling a new family of applications. We discuss a novel application of this laser digitizing system, in conjunction with emerging radio modem and pen-computer technology, to the automation of class or conference room note-taking.

  11. Functional transformations of odor inputs in the mouse olfactory bulb

    PubMed Central

    Adam, Yoav; Livneh, Yoav; Miyamichi, Kazunari; Groysman, Maya; Luo, Liqun; Mizrahi, Adi

    2014-01-01

    Sensory inputs from the nasal epithelium to the olfactory bulb (OB) are organized as a discrete map in the glomerular layer (GL). This map is then modulated by distinct types of local neurons and transmitted to higher brain areas via mitral and tufted cells. Little is known about the functional organization of the circuits downstream of glomeruli. We used in vivo two-photon calcium imaging for large scale functional mapping of distinct neuronal populations in the mouse OB, at single cell resolution. Specifically, we imaged odor responses of mitral cells (MCs), tufted cells (TCs) and glomerular interneurons (GL-INs). Mitral cells population activity was heterogeneous and only mildly correlated with the olfactory receptor neuron (ORN) inputs, supporting the view that discrete input maps undergo significant transformations at the output level of the OB. In contrast, population activity profiles of TCs were dense, and highly correlated with the odor inputs in both space and time. Glomerular interneurons were also highly correlated with the ORN inputs, but showed higher activation thresholds suggesting that these neurons are driven by strongly activated glomeruli. Temporally, upon persistent odor exposure, TCs quickly adapted. In contrast, both MCs and GL-INs showed diverse temporal response patterns, suggesting that GL-INs could contribute to the transformations MCs undergo at slow time scales. Our data suggest that sensory odor maps are transformed by TCs and MCs in different ways forming two distinct and parallel information streams. PMID:25408637

  12. Effects of control inputs on the estimation of stability and control parameters of a light airplane

    NASA Technical Reports Server (NTRS)

    Cannaday, R. L.; Suit, W. T.

    1977-01-01

    The maximum likelihood parameter estimation technique was used to determine the values of stability and control derivatives from flight test data for a low-wing, single-engine, light airplane. Several input forms were used during the tests to investigate the consistency of parameter estimates as it relates to inputs. These consistencies were compared by using the ensemble variance and estimated Cramer-Rao lower bound. In addition, the relationship between inputs and parameter correlations was investigated. Results from the stabilator inputs are inconclusive but the sequence of rudder input followed by aileron input or aileron followed by rudder gave more consistent estimates than did rudder or ailerons individually. Also, square-wave inputs appeared to provide slightly improved consistency in the parameter estimates when compared to sine-wave inputs.

  13. 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.

  14. Spatial Habitat Features Derived from Multiparametric Magnetic Resonance Imaging Data Are Associated with Molecular Subtype and 12-Month Survival Status in Glioblastoma Multiforme

    PubMed Central

    Lee, Joonsang; Narang, Shivali; Martinez, Juan; Rao, Ganesh; Rao, Arvind

    2015-01-01

    One of the most common and aggressive malignant brain tumors is Glioblastoma multiforme. Despite the multimodality treatment such as radiation therapy and chemotherapy (temozolomide: TMZ), the median survival rate of glioblastoma patient is less than 15 months. In this study, we investigated the association between measures of spatial diversity derived from spatial point pattern analysis of multiparametric magnetic resonance imaging (MRI) data with molecular status as well as 12-month survival in glioblastoma. We obtained 27 measures of spatial proximity (diversity) via spatial point pattern analysis of multiparametric T1 post-contrast and T2 fluid-attenuated inversion recovery MRI data. These measures were used to predict 12-month survival status (?12 or >12 months) in 74 glioblastoma patients. Kaplan-Meier with receiver operating characteristic analyses was used to assess the relationship between derived spatial features and 12-month survival status as well as molecular subtype status in patients with glioblastoma. Kaplan-Meier survival analysis revealed that 14 spatial features were capable of stratifying overall survival in a statistically significant manner. For prediction of 12-month survival status based on these diversity indices, sensitivity and specificity were 0.86 and 0.64, respectively. The area under the receiver operating characteristic curve and the accuracy were 0.76 and 0.75, respectively. For prediction of molecular subtype status, proneural subtype shows highest accuracy of 0.93 among all molecular subtypes based on receiver operating characteristic analysis. We find that measures of spatial diversity from point pattern analysis of intensity habitats from T1 post-contrast and T2 fluid-attenuated inversion recovery images are associated with both tumor subtype status and 12-month survival status and may therefore be useful indicators of patient prognosis, in addition to providing potential guidance for molecularly-targeted therapies in Glioblastoma multiforme. PMID:26368923

  15. Inner Heliospheric Evolution of a 'Stealth' CME Derived From Multi-view Imaging and Multipoint In-situ observations

    NASA Astrophysics Data System (ADS)

    Nieves-Chinchilla, T.; Vourlidas, A.; Stenborg, G.; Savani, N.; Koval, A.; Szabo, A.; Jian, L.; Hidalgo, M.; Lepping, R. P.

    2013-12-01

    Coronal mass ejections (CMEs) are the main driver of Space Weather. Therefore, a precise forecasting of their likely geo-effectiveness relies on an accurate tracking of their morphological and kinematical evolution throughout the interplanetary medium. However, single view-point observations require many assumptions to model the development of the features of CMEs. Before of the STEREO mission, the most common hypotheses were those of radial propagation and self-similar expansion. The use of different view-points shows that at least for some cases, those assumptions are no longer valid. Typical attributes that can now been confirmed to exist are departures from radial propagation, over-expansion, and rotation along the propagation axis. Understanding of the 3D development and evolution of the CME features is therefore of utmost importance to help establish the connection between remote and in-situ observations, and hence help forecast Space Weather. We present on analysis of the morphological and kinematical evolution of a STEREO B-directed CME on 2009 August 25-27. By means of a comprehensive analysis of remote imaging observations provided by SOHO, STEREO and SDO missions, and in-situ measurements recorded by Wind, ACE, and Messenger, we prove in this paper that the event exhibits signatures of rotation, changes in the direction of propagation, and/or interaction with other magnetic obstacles. We propose a method to investigate the change of the CME Tilt from the analysis of Height-Time measurements and we found that the results are consistent with in-situ reconstructions and solar source analysis. If this result is validated in further work, it may have important implications for space weather studies and new generation of inner heliospheric missions because it will allow us to infer the ICME orientation at 1 AU using remote sensing observations of the first stages of the CME.

  16. Convergence of multisensory inputs in the Xenopus tadpole tectum

    PubMed Central

    Hiramoto, Masateru; Cline, Hollis

    2010-01-01

    The integration of multisensory information takes place in the optic tectum where visual and auditory/mechanosensory inputs converge and regulate motor outputs. The circuits which integrate multisensory information are poorly understood. In an effort to identify the basic components of a multisensory integrative circuit, we determined the projections of the mechanosensory input from the periphery to the optic tectum and compared their distribution to the retinotectal inputs in Xenopus laevis tadpoles using dye-labelling methods. The peripheral ganglia of the lateral line system project to the ipsilateral hindbrain and the axons representing mechanosensory inputs along the anterior/posterior body axis are mapped along the ventrodorsal axis in the axon tract in the dorsal column of the hindbrain. Hindbrain neurons project axons to the contralateral optic tectum. The neurons from anterior and posterior hindbrain regions project axons to the dorsal and ventral tectum, respectively. While the retinotectal axons project to a superficial lamina in the tectal neuropil, the hindbrain axons project to a deep neuropil layer. Calcium imaging showed that multimodal inputs converge on tectal neurons. The layer specific projections of the hindbrain and retinal axons suggest a functional segregation of sensory inputs to proximal and distal tectal cell dendrites, respectively. PMID:19813244

  17. Assessment of urban tree growth from structure, nutrients and composition data derived from airborne lidar and imaging spectroscopy

    NASA Astrophysics Data System (ADS)

    Gu, H.; Townsend, P. A.; Singh, A.

    2014-12-01

    Urban forests provide important ecosystem services related to climate, nutrients, runoff and aesthetics. Assessment of variations in urban forest growth is critical to urban management and planning, as well as to identify responses to climate and other environmental changes. We estimated annual relative basal area increment by tree rings from 37 plots in Madison, Wisconsin and neighboring municipalities. We related relative basal area growth to variables of vegetation traits derived from remote sensing, including structure (aboveground biomass, diameter, height, basal area, crown width and crown length) from discrete-return airborne lidar, and biochemical variables (foliar nitrogen, carbon, lignin, cellulose, fiber and LMA), spectral indices (NDVI, NDWI, PRI, NDII etc.) and species composition from AVIRIS hyperspectral imagery. Variations in tree growth was mainly correlated with tree species composition (R2 = 0.29, RMSE = 0.004) with coniferous stands having a faster growth rate than broadleaf plots. Inclusion of stand basal area improved model prediction from R2 = 0.29 to 0.35, with RMSE = 0.003. Then, we assessed the growth by functional type, we found that foliar lignin concentration and the proportion of live coniferous trees explained 57% variance in the growth of conifer stands. In contrast, broadleaf forest growth was more strongly correlated with species composition and foliar carbon (R2 = 0.59, RMSE = 0.003). Finally, we compared the relative basal area growth by species. In our study area, red pine and white pine exhibited higher growth rates than other species, while white oak plots grew slowest. There is a significant negative relationship between tree height and the relative growth in red pine stands (r = -0.95), as well as a strong negative relationship between crown width and the relative growth in white pine stands (r = -0.87). Growth declines as trees grow taller and wider may partly be the result of reduced photosynthesis and water availability. We also found that canopy cellulose content was negatively correlated with growth in white oak (r = -0.59), which could be caused by trade off of carbon allocation from shoot storage to leaves. These results demonstrate the potential of lidar and hyperspectral imagery to characterize important traits associated with biomass accumulation in urban forests.

  18. Novel fluorine-18 labeled 5-(1-pyrrolidinylsulfonyl)-7-azaisatin derivatives as potential PET tracers for in vivo imaging of activated caspases in apoptosis.

    PubMed

    Waldmann, Christopher M; Hermann, Sven; Faust, Andreas; Riemann, Burkhard; Schober, Otmar; Schäfers, Michael; Haufe, Günter; Kopka, Klaus

    2015-09-01

    The programmed type I cell death, defined as apoptosis, is induced by complex regulated signaling pathways that trigger the intracellular activation of executioner caspases-3, -6 and -7. Once activated, these enzymes initiate cellular death through cleavage of proteins which are responsible for DNA repair, signaling and cell maintenance. Several radiofluorinated inhibitors of caspases-3 and -7, comprising a moderate lipophilic 5-(1-pyrrolidinylsulfonyl)isatin lead structure, are currently being investigated for imaging apoptosis in vivo by us and others. The purpose of this study was to increase the intrinsic hydrophilicity of the aforementioned lead structure to alter the pharmacokinetic behavior of the resulting caspase-3 and -7 targeted radiotracer. Therefore, fluorinated and non-fluorinated derivatives of 5-(1-pyrrolidinylsulfonyl)-7-azaisatin were synthesized and tested for their inhibitory properties against recombinant caspases-3 and -7. Fluorine-18 has been introduced by copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) of an alkyne precursor with 2-[(18)F]fluoroethylazide. Using dynamic micro-PET biodistribution studies in vivo the kinetic behavior of one promising PET-compatible 5-pyrrolidinylsulfonyl 7-azaisatin derivative has been compared to a previously described isatin based radiotracer. PMID:26210158

  19. Patch-Clamp Recordings and Calcium Imaging Followed by Single-Cell PCR Reveal the Developmental Profile of 13 Genes in iPSC-Derived Human Neurons

    PubMed Central

    Belinsky, Glenn S.; Rich, Matthew T.; Sirois, Carissa L.; Short, Shaina M.; Pedrosa, Erika; Lachman, Herbert M.; Antic, Srdjan D.

    2013-01-01

    Molecular genetic studies are typically performed on homogenized biological samples, resulting in contamination from non-neuronal cells. To improve expression profiling of neurons we combined patch recordings with single-cell PCR. Two iPSC lines (healthy subject and 22q11.2 deletion), were differentiated into neurons. Patch electrode recordings were performed on 229 human cells from Day-13 to Day-88, followed by capture and single-cell PCR for 13 genes: ACTB, HPRT, vGLUT1, ?TUBIII, COMT, DISC1, GAD1, PAX6, DTNBP1, ERBB4, FOXP1, FOXP2, and GIRK2. Neurons derived from both iPSC lines expressed ?TUBIII, fired action potentials, and experienced spontaneous depolarizations (UP states) ~2 weeks before vGLUT1, GAD1 and GIRK2 appeared. Multisite calcium imaging revealed that these UP states were not synchronized among hESC-H9-derived neurons. The expression of FOXP1, FOXP2 and vGLUT1 was lost after 50 days in culture, in contrast to other continuously expressed genes. When gene expression was combined with electrophysiology, two subsets of genes were apparent; those irrelevant to spontaneous depolarizations (including vGLUT1, GIRK2, FOXP2 and DISC1) and those associated with spontaneous depolarizations (GAD1 and ERBB4). The results demonstrate that in the earliest stages of neuron development, it is useful to combine genetic analysis with physiological characterizations, on a cell-to-cell basis. PMID:24157591

  20. Present State of the Long Valley Caldera/California Derived From DC-Resistivity Imaging and Self-Potential Measurements

    NASA Astrophysics Data System (ADS)

    Flechsig, C.; Schuetze, C.; Jacobs, F.; Serfling, U.

    2001-12-01

    The geoelectrical methods make sense to apply in volcanic areas since porosity, permeability, ionic mobility, ionic concentration in rock fluids, and cation exchange capability are modified by volcanic - magmatic activity directly and processes generated by volcanism (geothermal systems). Resistivity of volcanic rocks is a meaningful indicator for changes in porosity and ionic mobility, ionic concentrations in fluids, mobility of fluids caused by changes in temperature. A large-scale Direct-Current (DC) imaging investigation of the Long Valley system included both an active 21 km DC-survey line across the caldera and the mapping of natural self-potential (SP) anomalies in the western and central part. The deep sounding Electrical Resistivity Tomography (ERT) was applied successfully. The 21 km long dipole-dipole profile in east-west direction according to Wannamaker et al. (1991) was selected deliberately in order to compare the results. For the detection of the potential differences special stand alone transient recorders were applied. This kind of signal recording offers the possibility of statistical methods for signal enhancement. The recorded time series yield information not only about the DC-resistivity than special effects like induced polarization events and self-potentials. The first application of tomographic resistivity sounding in Long Valley is resulting in a recent 2-D model of resistivity distribution in subsurface after the resurgence of volcanic activity in the 80ies. The inversion result reveals numerous resistivity structures which are in very good correlation with known geologic and tectonic structures. The tomographical inversion of DC-data was carried out with the goal to study the geological structures of the Long Valley Caldera down to 3-4 km, especially in the part affected by the resurgent dome and the hydrothermal system by use of geoelectrical parameters. The important structural components include low-resistivity regions beneath the western half of caldera, which are originated by the shallow hydrothermal system. A large conductive segment under the Medial Graben, already described by Wannamaker et al. (1991), can also be seen, whereas the majority of resurgent dome appears highly resistive. The interpretation of the resistivity model is sustained by self-potential anomalies, measured in the western part of caldera, by the comparison with known fault zones and by implications for fluid flow inferred from geothermal data, whereupon the resurgent dome is not influenced by the present hydrothermal fluid flow.

  1. A ¹¹C-labeled 1,4-dihydroquinoline derivative as a potential PET tracer for imaging of redox status in mouse brain.

    PubMed

    Okamura, Toshimitsu; Okada, Maki; Kikuchi, Tatsuya; Wakizaka, Hidekatsu; Zhang, Ming-Rong

    2015-12-01

    A disturbance in redox balance has been implicated in the pathogenesis of a number of diseases. This study sought to examine the feasibility of imaging brain redox status using a (11)C-labeled dihydroquinoline derivative ([(11)C]DHQ1) for positron emission tomography (PET). The lipophilic PET tracer [(11)C]DHQ1 was rapidly oxidized to its hydrophilic form in mouse brain homogenate. The redox modulators diphenyleneiodonium and apocynin significantly reduced the initial velocity of [(11)C]DHQ1 oxidation, and apocynin also caused concentration-dependent inhibition of the initial velocity. Moreover, [(11)C]DHQ1 readily entered the brain by diffusion after administration and underwent oxidation into the hydrophilic cationic form, which then slowly decreased. By contrast, apocynin treatment inhibited the in vivo oxidation of [(11)C]DHQ1 to the hydrophilic cationic form, leading to a rapid decrease of radioactivity in the brain. Thus, the difference in the [(11)C]DHQ1 kinetics reflects the alteration in redox status caused by apocynin. In conclusion, [(11)C]DHQ1 is a potential PET tracer for imaging of redox status in the living brain. PMID:26082015

  2. 99mTc(CO)3-Labeled Benzothiazole Derivatives Preferentially Bind Cerebrovascular Amyloid: Potential Use as Imaging Agents for Cerebral Amyloid Angiopathy.

    PubMed

    Jia, Jianhua; Cui, Mengchao; Dai, Jiapei; Liu, Boli

    2015-08-01

    Cerebral amyloid angiopathy (CAA) is a disorder affecting the elderly that is characterized by amyloid-β (Aβ) deposition in blood vessel walls of the brain. A series of 99mTc(CO)3-labeled benzothiazole derivatives as potential SPECT imaging probes for cerebrovascular Aβ deposition is reported. Rhenium surrogate displayed high affinities to Aβ aggregates with Ki values ranging from 106 to 42 nM, and they strongly stained Aβ deposits in transgenic mice (Tg) and Alzheimer's disease (AD) patients. In vitro autoradiography on brain sections of Tg and AD patients confirmed that [99mTc]24 possessed sufficient affinity for Aβ plaques, and [99mTc]24 could only label Aβ deposition in blood vessels but not Aβ plaques in the parenchyma of the brain of AD patients. Moreover, [99mTc]24 possessed favorable initial uptake (1.21% ID/g) and fast blood washout (blood2 min/blood60 min=23) in normal mice. These preliminary results suggest that [99mTc]24 may be used as an Aβ imaging probe for the detection of CAA. PMID:26065726

  3. 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

  4. 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. PMID:25821451

  5. Model based inversion for deriving maps of histological parameters characteristic of cancer from ex-vivo multispectral images of the colon.

    PubMed

    Claridge, Ela; Hidović-Rowe, Džena

    2014-04-01

    A model-based inversion method was used to obtain quantitative estimates of histological parameters from multispectral images of the colon and to examine their potential for discriminating between normal and pathological tissues. Pixel-wise estimates of the mucosal blood volume fraction, density of the scattering particles and thickness were derived using a two-stage method. In the first (forward) stage reflectance spectra corresponding to given instances of the parameter values were computed using Monte Carlo simulation of photon propagation through a multi-layered tissue. In the second (inversion) stage the parameter values were obtained via optimization using an iterated conditional modes algorithm based on Discrete Markov Random Fields. The method was validated on computer generated data contaminated with noise giving a mean normalized root mean square deviation (NRMSD) of 2.04. Validation on ex vivo images demonstrated that parametric maps show gross correspondence with histological features of mucosa characteristic of cancerous, precancerous and noncancerous colon lesions. The key signs of abnormality were shown to be the increase in the blood volume fraction and decrease in the density of scattering particles. PMID:24239991

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

    PubMed Central

    Mokaleng, Botshelo B.; Ebenhan, Thomas; Ramesh, Suhas; Govender, Thavendran; Kruger, Hendrik G.; 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 67/68Ga-citrate or 18F-FDG. We report here TBIA101, an antimicrobial peptide derivative that was conjugated to DOTA and radiolabeled with 68Ga 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 68Gallium-radiolabeling. µPET/CT using 68Ga-DOTA-TBIA101 was employed to detect muscular E. coli-infection in BALB/c mice, as warranted by the in vitro results. 68Ga-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

  7. Repositioning Recitation Input in College English Teaching

    ERIC Educational Resources Information Center

    Xu, Qing

    2009-01-01

    This paper tries to discuss how recitation input helps overcome the negative influences on the basis of second language acquisition theory and confirms the important role that recitation input plays in improving college students' oral and written English.

  8. Detection of Floating Inputs in Logic Circuits

    NASA Technical Reports Server (NTRS)

    Cash, B.; Thornton, M. G.

    1984-01-01

    Simple modification of oscilloscope probe allows easy detection of floating inputs or tristate outputs in digital-IC's. Oscilloscope probe easily modified with 1/4 W resistor and switch for detecting floating inputs in CMOS logic circuits.

  9. Investigating the robustness of the new Landsat-8 Operational Land Imager derived texture metrics in estimating plantation forest aboveground biomass in resource constrained areas

    NASA Astrophysics Data System (ADS)

    Dube, Timothy; Mutanga, Onisimo

    2015-10-01

    The successful launch of the 30-m Landsat-8 Operational Land Imager (OLI) pushbroom sensor offers a new primary data source necessary for aboveground biomass (AGB) estimation, especially in resource-limited environments. In this work, the strength and performance of Landsat-8 OLI image derived texture metrics (i.e. texture measures and texture ratios) in estimating plantation forest species AGB was investigated. It was hypothesized that the sensor's pushbroom design, coupled with the presence of refined spectral properties, enhanced radiometric resolution (i.e. from 8 bits to 12 bits) and improved signal-to-noise ratio have the potential to provide detailed spectral information necessary for significantly strengthening AGB estimation in medium-density forest canopies. The relationship between image texture metrics and measurements of forest attributes can be used to help characterize complex forests, and enhance fine vegetation biophysical properties, a difficult challenge when using spectral vegetation indices especially in closed canopies. This study examines the prospects of using Landsat-8 OLI sensor derived texture metrics for estimating AGB for three medium-density plantation forest species in KwaZulu Natal, South Africa. In order to achieve this objective, three unique data pre-processing techniques were tested (analysis I: Landsat-8 OLI raw spectral-bands vs. raw texture bands; analysis II: Landsat-8 OLI raw spectral-band ratios vs. texture band ratios and analysis III: Landsat-8 OLI derived vegetation indices vs. texture band ratios). The landsat-8 OLI derived texture parameters were examined for robustness in estimating AGB using linear regression, stepwise-multiple linear regression and stochastic gradient boosting regression models. The results of this study demonstrated that all texture parameters particularly band texture ratios calculated using a 3 × 3 window size, could enhance AGB estimation when compared to simple spectral reflectance, simple band ratios and the most popular spectral vegetation indices. For instance, the use of combined texture ratios yielded the highest R2 values of 0.76 (RMSE = 9.55 t ha-1 (18.07%) and CV-RMSE of 0.18); 0.74 (RMSE = 12.81 t ha-1 (17.72%) and CV-RMSE of 0.08); 0.74 (RMSE = 12.67 t ha-1 (06.15%) and CV-RMSE of 0.06) and 0.53 (RMSE = 20.15 t ha-1 (14.40%) and CV-RMSE of 0.15) overall for Eucalyptus dunii, Eucalyptus grandis, Pinus taeda individually and all species, respectively. Overall, the findings of this study provide the necessary insight and motivation to the remote sensing community, particularly in resource constrained regions, to shift towards embracing various texture metrics obtained from the readily-available and cheap multispectral Landsat-8 OLI sensor.

  10. Biogenic inputs to ocean mixing.

    PubMed

    Katija, Kakani

    2012-03-15

    Recent studies have evoked heated debate about whether biologically generated (or biogenic) fluid disturbances affect mixing in the ocean. Estimates of biogenic inputs have shown that their contribution to ocean mixing is of the same order as winds and tides. Although these estimates are intriguing, further study using theoretical, numerical and experimental techniques is required to obtain conclusive evidence of biogenic mixing in the ocean. Biogenic ocean mixing is a complex problem that requires detailed understanding of: (1) marine organism behavior and characteristics (i.e. swimming dynamics, abundance and migratory behavior), (2) mechanisms utilized by swimming animals that have the ability to mix stratified fluids (i.e. turbulence and fluid drift) and (3) knowledge of the physical environment to isolate contributions of marine organisms from other sources of mixing. In addition to summarizing prior work addressing the points above, observations on the effect of animal swimming mode and body morphology on biogenic fluid transport will also be presented. It is argued that to inform the debate on whether biogenic mixing can contribute to ocean mixing, our studies should focus on diel vertical migrators that traverse stratified waters of the upper pycnocline. Based on our understanding of mixing mechanisms, body morphologies, swimming modes and body orientation, combined with our knowledge of vertically migrating populations of animals, it is likely that copepods, krill and some species of gelatinous zooplankton and fish have the potential to be strong sources of biogenic mixing. PMID:22357597

  11. 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.

  12. 7 CFR 3430.15 - Stakeholder input.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 15 2012-01-01 2012-01-01 false Stakeholder input. 3430.15 Section 3430.15... ADMINISTRATIVE PROVISIONS Pre-award: Solicitation and Application § 3430.15 Stakeholder input. Section 103(c)(2... programs. NIFA will provide instructions for submission of stakeholder input in the RFA. NIFA will...

  13. 7 CFR 3430.607 - Stakeholder input.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 15 2012-01-01 2012-01-01 false Stakeholder input. 3430.607 Section 3430.607... ADMINISTRATIVE PROVISIONS Beginning Farmer and Rancher Development Program § 3430.607 Stakeholder input. NIFA shall seek and obtain stakeholder input through a variety of forums (e.g., public meetings, request...

  14. 7 CFR 3430.15 - Stakeholder input.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 15 2014-01-01 2014-01-01 false Stakeholder input. 3430.15 Section 3430.15... ADMINISTRATIVE PROVISIONS Pre-award: Solicitation and Application § 3430.15 Stakeholder input. Section 103(c)(2... programs. NIFA will provide instructions for submission of stakeholder input in the RFA. NIFA will...

  15. 7 CFR 3430.15 - Stakeholder input.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 15 2011-01-01 2011-01-01 false Stakeholder input. 3430.15 Section 3430.15... ADMINISTRATIVE PROVISIONS Pre-award: Solicitation and Application § 3430.15 Stakeholder input. Section 103(c)(2... programs. CSREES will provide instructions for submission of stakeholder input in the RFA. CSREES...

  16. 7 CFR 3430.15 - Stakeholder input.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 15 2013-01-01 2013-01-01 false Stakeholder input. 3430.15 Section 3430.15... ADMINISTRATIVE PROVISIONS Pre-award: Solicitation and Application § 3430.15 Stakeholder input. Section 103(c)(2... programs. NIFA will provide instructions for submission of stakeholder input in the RFA. NIFA will...

  17. 7 CFR 3430.607 - Stakeholder input.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 15 2014-01-01 2014-01-01 false Stakeholder input. 3430.607 Section 3430.607... ADMINISTRATIVE PROVISIONS Beginning Farmer and Rancher Development Program § 3430.607 Stakeholder input. NIFA shall seek and obtain stakeholder input through a variety of forums (e.g., public meetings, request...

  18. 7 CFR 3430.15 - Stakeholder input.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 15 2010-01-01 2010-01-01 false Stakeholder input. 3430.15 Section 3430.15... Stakeholder input. Section 103(c)(2) of the Agricultural Research, Extension, and Education Reform Act of 1998... RFAs for competitive programs. CSREES will provide instructions for submission of stakeholder input...

  19. 7 CFR 3430.907 - Stakeholder input.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 15 2014-01-01 2014-01-01 false Stakeholder input. 3430.907 Section 3430.907... ADMINISTRATIVE PROVISIONS New Era Rural Technology Competitive Grants Program § 3430.907 Stakeholder input. NIFA shall seek and obtain stakeholder input through a variety of forums (e.g., public meetings, requests...

  20. 7 CFR 3430.607 - Stakeholder input.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 15 2011-01-01 2011-01-01 false Stakeholder input. 3430.607 Section 3430.607... ADMINISTRATIVE PROVISIONS Beginning Farmer and Rancher Development Program § 3430.607 Stakeholder input. CSREES shall seek and obtain stakeholder input through a variety of forums (e.g., public meetings, request...

  1. 7 CFR 3430.607 - Stakeholder input.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 15 2013-01-01 2013-01-01 false Stakeholder input. 3430.607 Section 3430.607... ADMINISTRATIVE PROVISIONS Beginning Farmer and Rancher Development Program § 3430.607 Stakeholder input. NIFA shall seek and obtain stakeholder input through a variety of forums (e.g., public meetings, request...

  2. 7 CFR 3430.907 - Stakeholder input.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 15 2013-01-01 2013-01-01 false Stakeholder input. 3430.907 Section 3430.907... ADMINISTRATIVE PROVISIONS New Era Rural Technology Competitive Grants Program § 3430.907 Stakeholder input. NIFA shall seek and obtain stakeholder input through a variety of forums (e.g., public meetings, requests...

  3. 7 CFR 3430.907 - Stakeholder input.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 15 2012-01-01 2012-01-01 false Stakeholder input. 3430.907 Section 3430.907... ADMINISTRATIVE PROVISIONS New Era Rural Technology Competitive Grants Program § 3430.907 Stakeholder input. NIFA shall seek and obtain stakeholder input through a variety of forums (e.g., public meetings, requests...

  4. 7 CFR 3430.907 - Stakeholder input.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 15 2011-01-01 2011-01-01 false Stakeholder input. 3430.907 Section 3430.907... ADMINISTRATIVE PROVISIONS New Era Rural Technology Competitive Grants Program § 3430.907 Stakeholder input. CSREES shall seek and obtain stakeholder input through a variety of forums (e.g., public...

  5. 7 CFR 3430.607 - Stakeholder input.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 15 2010-01-01 2010-01-01 false Stakeholder input. 3430.607 Section 3430.607 Agriculture Regulations of the Department of Agriculture (Continued) COOPERATIVE STATE RESEARCH, EDUCATION... § 3430.607 Stakeholder input. CSREES shall seek and obtain stakeholder input through a variety of...

  6. 7 CFR 3430.907 - Stakeholder input.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 15 2010-01-01 2010-01-01 false Stakeholder input. 3430.907 Section 3430.907 Agriculture Regulations of the Department of Agriculture (Continued) COOPERATIVE STATE RESEARCH, EDUCATION... Program § 3430.907 Stakeholder input. CSREES shall seek and obtain stakeholder input through a variety...

  7. 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.…

  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. Input Devices for Young Handicapped Children.

    ERIC Educational Resources Information Center

    Morris, Karen

    The versatility of the computer can be expanded considerably for young handicapped children by using input devices other than the typewriter-style keyboard. Input devices appropriate for young children can be classified into four categories: alternative keyboards, contact switches, speech input devices, and cursor control devices. Described are…

  10. 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.

  11. 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.

  12. 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

  13. PREVIMER : Meteorological inputs and outputs

    NASA Astrophysics Data System (ADS)

    Ravenel, H.; Lecornu, F.; Kerlguer, 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 Ocanographique de la Marine, SHOM), the French National Weather Service (Mto-France), the French public science and technology research institute (Institut de Recherche pour le Dveloppement, IRD), the European Institute of Marine Studies (Institut Universitaire Europen 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.

  14. Kinetic quantitation of cerebral PET-FDG studies without concurrent blood sampling: statistical recovery of the arterial input function.

    PubMed

    O'Sullivan, F; Kirrane, J; Muzi, M; O'Sullivan, J N; Spence, A M; Mankoff, D A; Krohn, K A

    2010-03-01

    Kinetic quantitation of dynamic positron emission tomography (PET) studies via compartmental modeling usually requires the time-course of the radio-tracer concentration in the arterial blood as an arterial input function (AIF). For human and animal imaging applications, significant practical difficulties are associated with direct arterial sampling and as a result there is substantial interest in alternative methods that require no blood sampling at the time of the study. A fixed population template input function derived from prior experience with directly sampled arterial curves is one possibility. Image-based extraction, including requisite adjustment for spillover and recovery, is another approach. The present work considers a hybrid statistical approach based on a penalty formulation in which the information derived from a priori studies is combined in a Bayesian manner with information contained in the sampled image data in order to obtain an input function estimate. The absolute scaling of the input is achieved by an empirical calibration equation involving the injected dose together with the subject's weight, height and gender. The technique is illustrated in the context of (18)F -Fluorodeoxyglucose (FDG) PET studies in humans. A collection of 79 arterially sampled FDG blood curves are used as a basis for a priori characterization of input function variability, including scaling characteristics. Data from a series of 12 dynamic cerebral FDG PET studies in normal subjects are used to evaluate the performance of the penalty-based AIF estimation technique. The focus of evaluations is on quantitation of FDG kinetics over a set of 10 regional brain structures. As well as the new method, a fixed population template AIF and a direct AIF estimate based on segmentation are also considered. Kinetics analyses resulting from these three AIFs are compared with those resulting from radially sampled AIFs. The proposed penalty-based AIF extraction method is found to achieve significant improvements over the fixed template and the segmentation methods. As well as achieving acceptable kinetic parameter accuracy, the quality of fit of the region of interest (ROI) time-course data based on the extracted AIF, matches results based on arterially sampled AIFs. In comparison, significant deviation in the estimation of FDG flux and degradation in ROI data fit are found with the template and segmentation methods. The proposed AIF extraction method is recommended for practical use. PMID:19709971

  15. 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.

  16. A Web Browsing System by Eye-gaze Input

    NASA Astrophysics Data System (ADS)

    Abe, Kiyohiko; Owada, Kosuke; Ohi, Shoichi; Ohyama, Minoru

    We have developed an eye-gaze input system for people with severe physical disabilities, such as amyotrophic lateral sclerosis (ALS) patients. This system utilizes a personal computer and a home video camera to detect eye-gaze under natural light. The system detects both vertical and horizontal eye-gaze by simple image analysis, and does not require special image processing units or sensors. We also developed the platform for eye-gaze input based on our system. In this paper, we propose a new web browsing system for physically disabled computer users as an application of the platform for eye-gaze input. The proposed web browsing system uses a method of direct indicator selection. The method categorizes indicators by their function. These indicators are hierarchized relations; users can select the felicitous function by switching indicators group. This system also analyzes the location of selectable object on web page, such as hyperlink, radio button, edit box, etc. This system stores the locations of these objects, in other words, the mouse cursor skips to the object of candidate input. Therefore it enables web browsing at a faster pace.

  17. CARMENES. III. CARMENCITA, the input catalogue

    NASA Astrophysics Data System (ADS)

    Caballero, J. A.; Cortés-Contreras, M.; López-Santiago, J.; Alonso-Floriano, F. J.; Klutsch, A.; Montes, D.; Morales, J. C.; Mundt, R.; Ribas, I.; Reiners, A.; Quirrenbach, A.; Amado, P. J.; Carmenes Consortium

    2013-05-01

    CARMENES, the new near-infrared/optical high-resolution spectrograph for the 3.5 m Calar Alto Telescope, is expected to see its first light in early 2014. Before that, we must have chosen carefully the 300 M dwarfs to which CARMENES will look for terrestrial exoplanets with the radial-velocity method under guaranteed time. CARMENCITA, the CARMENES Cool dwarf Information and daTa Archive, our ``input catalogue'', will be the most comprehensive database of M dwarfs ever built. It already contains dozens of parameters measured by us or compiled from the literature for over 1300 bright M dwarfs in the solar neighbourhood: coordinates, spectral indices, photometry at different bandpasses, parallaxes and spectro-photometric distances, rotational and radial velocities, Hα equivalent widths, X-ray count rates and hardness ratios, close and wide multiplicity data, proper motions, Galactocentric space velocities, full references, and much more parameters. The private on-line catalogue, including preparatory science (i.e., high-resolution imaging, low- and high-resolution spectroscopy), will be eventually public as a CARMENES legacy.

  18. Synchronized amplification of local information transmission by peripheral retinal input.

    PubMed

    Jadzinsky, Pablo D; Baccus, Stephen A

    2015-01-01

    Sensory stimuli have varying statistics influenced by both the environment and by active sensing behaviors that rapidly and globally change the sensory input. Consequently, sensory systems often adjust their neural code to the expected statistics of their sensory input to transmit novel sensory information. Here, we show that sudden peripheral motion amplifies and accelerates information transmission in salamander ganglion cells in a 50 ms time window. Underlying this gating of information is a transient increase in adaptation to contrast, enhancing sensitivity to a broader range of stimuli. Using a model and natural images, we show that this effect coincides with an expected increase in information in bipolar cells after a global image shift. Our findings reveal the dynamic allocation of energy resources to increase neural activity at times of expected high information content, a principle of adaptation that balances the competing requirements of conserving spikes and transmitting information. PMID:26568312

  19. 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

  20. Semi-automated segmentation of solid and GGO nodules in lung CT images using vessel-likelihood derived from local foreground structure

    NASA Astrophysics Data System (ADS)

    Yaguchi, Atsushi; Okazaki, Tomoya; Takeguchi, Tomoyuki; Matsumoto, Sumiaki; Ohno, Yoshiharu; Aoyagi, Kota; Yamagata, Hitoshi

    2015-03-01

    Reflecting global interest in lung cancer screening, considerable attention has been paid to automatic segmentation and volumetric measurement of lung nodules on CT. Ground glass opacity (GGO) nodules deserve special consideration in this context, since it has been reported that they are more likely to be malignant than solid nodules. However, due to relatively low contrast and indistinct boundaries of GGO nodules, segmentation is more difficult for GGO nodules compared with solid nodules. To overcome this difficulty, we propose a method for accurately segmenting not only solid nodules but also GGO nodules without prior information about nodule types. First, the histogram of CT values in pre-extracted lung regions is modeled by a Gaussian mixture model and a threshold value for including high-attenuation regions is computed. Second, after setting up a region of interest around the nodule seed point, foreground regions are extracted by using the threshold and quick-shift-based mode seeking. Finally, for separating vessels from the nodule, a vessel-likelihood map derived from elongatedness of foreground regions is computed, and a region growing scheme starting from the seed point is applied to the map with the aid of fast marching method. Experimental results using an anthropomorphic chest phantom showed that our method yielded generally lower volumetric measurement errors for both solid and GGO nodules compared with other methods reported in preceding studies conducted using similar technical settings. Also, our method allowed reasonable segmentation of GGO nodules in low-dose images and could be applied to clinical CT images including part-solid nodules.

  1. Longitudinal monitoring adipose-derived stem cell survival by PET imaging hexadecyl-4-{sup 124}I-iodobenzoate in rat myocardial infarction model

    SciTech Connect

    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

    2015-01-02

    Highlights: • We developed a safe, simple and appropriate stem cell labeling method with {sup 124}I-HIB. • ADSC survival can be monitored with PET in MI model via direct labeling. • Tracking of ADSC labeled with {sup 124}I-HIB was possible for 3 days in MI model using PET. • ADSC viability and differentiation were not affected by {sup 124}I-HIB labeling. • Survival of ADSC in living bodies can be longitudinally tracked with PET imaging. - Abstract: 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-{sup 124}I-iodobenzoate ({sup 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 {sup 124}I-HIB, and radiolabeled ADSCs were transplanted into the myocardium of normal and MI model. In the group of {sup 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 {sup 124}I-HIB labeling. In vivo tracking of the {sup 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, {sup 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.

  2. SU-C-BRE-05: PTV Margin Determination Based On Tumor Radiobiological Characteristics and Geometric Uncertainties Derived From Daily Cone- Beam CT Images

    SciTech Connect

    Selvaraj, J

    2014-06-15

    Purpose: To determine required PTV margins for ≤1% loss in mean population TCP using systematic (Σ) and random (σ) errors calculated from daily cone-beam CT (CBCT) images of head and neck patients. Methods: Daily CBCT images were acquired for 50 head and neck patients. The CBCT image sets acquired at each fraction were registered with planning CT to obtain positional errors for each patient for each fraction. Systematic and random errors were calculated from data collected for 50 patients as described in IPEM On Target report. CTV delineation uncertainty of 2mm is added quadratically to systematic error. Assuming a spherical target volume, the dose in each voxel of target volume is summed for each fraction in the treatment by shifting the dose grid to calculate mean population TCP inclusive of geometric uncertainties using a Monte Carlo method. These simulations were repeated for the set of Σ and σ in each axis for different PTV margins and drop in TCP for each margin are obtained. In order to study the effect of dose-response curve on PTV margins, two different σα of 0.048 Gy-1 and 0.218 Gy-1 representing steep and shallow dose-response curves are studied. Σ were 2.5, 2.5, 2.1 mm and σ were 0.3, 0.3 0.2 mm respectively in x, y and z axis respectively. Results: PTV margins based on tumor radiobiological characteristics are 4.8, 4.8 and 4 mm in x, y and z axis assuming 25 treatment fractions for σα 0.048 Gy-1 (steep) and 4.2,4.2 and 2.2 for σα of 0.218 Gy-1 (shallow). While the TCP-based margins did not differ much in x and y axis, it is considerably smaller in z axis for shallow DRC. Conclusion: TCP based margins are substantially smaller than physical dose-based margin recipes. This study also demonstrates the importance of considering tumor radiobiological characteristics while deriving margins.

  3. The use of mass spectrometry imaging to predict treatment response of patient-derived xenograft models of triple-negative breast cancer.

    PubMed

    Mascini, Nadine E; Eijkel, Gert B; ter Brugge, Petra; Jonkers, Jos; Wesseling, Jelle; Heeren, Ron M A

    2015-02-01

    In recent years, mass spectrometry imaging (MSI) has been shown to be a promising technique in oncology. The effective application of MSI, however, is hampered by the complexity of the generated data. Bioinformatic approaches that reduce the complexity of these data are needed for the effective use in a (bio)medical setting. This holds especially for the analysis of tissue microarrays (TMA), which consist of hundreds of small tissue cores. Here we present an approach that combines MSI on tissue microarrays with principal component linear discriminant analysis (PCA-LDA) to predict treatment response. The feasibility of such an approach was evaluated on a set of patient-derived xenograft models of triple-negative breast cancer (TNBC). PCA-LDA was used to classify TNBC tumor tissues based on the proteomic information obtained with matrix-assisted laser desorption ionization (MALDI) MSI from the TMA surface. Classifiers based on two different tissue microarrays from the same tumor models showed overall classification accuracies between 59 and 77%, as determined by cross-validation. Reproducibility tests revealed that the two models were similar. A clear effect of intratumor heterogeneity of the classification scores was observed. These results demonstrate that the analysis of MALDI-MSI data by PCA-LDA is a valuable approach for the classification of treatment response and tumor heterogeneity in breast cancer. PMID:25553735

  4. Quantitative prediction of radio frequency induced local heating derived from measured magnetic field maps in magnetic resonance imaging: A phantom validation at 7 T

    SciTech Connect

    Zhang, Xiaotong; Liu, Jiaen; Van de Moortele, Pierre-Francois; Schmitter, Sebastian; He, Bin

    2014-12-15

    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.

  5. 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.

  6. Design, Synthesis, and Evaluation of 1,4,7,10-Tetraazacyclododecane-1,4,7-triacetic Acid-Derived, Redox-Sensitive Contrast Agents for Magnetic Resonance Imaging

    PubMed Central

    Raghunand, Natarajan; Guntle, Gerald P.; Gokhale, Vijay; Nichol, Gary S.; Mash, Eugene A.; Jagadish, Bhumasamudram

    2010-01-01

    The design and synthesis of three 1,4,7,10-tetraazacyclododecane-1,4,7-triacetic acid (DO3A) derivatives bearing linkers with terminal thiol groups and a preliminary evaluation of their potential for use in assembling redox-sensitive Magnetic Resonance Imaging (MRI) contrast agents are reported. The linkers were selected based on computational docking with a crystal structure of human serum albumin (HSA). Gd(III)-DO3A and Eu(III)-DO3A complexes were synthesized, and the structure of one complex was established by X-ray crystallographic analysis. The binding to HSA of a Gd(III)-DO3A complex bearing a thiol-terminated 3,6-dioxanonyl chain was competitively inhibited by homocysteine and by the corresponding Eu chelate. Binding to HSA was abolished when the terminal thiol group of this complex was absent. The longitudinal water-proton relaxivities (r1) of the three Gd(III)-DO3A complexes and of two Gd(III)-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) complexes were measured in saline at 7 Tesla. The DO3A complexes exhibited smaller r1 values, in both bound and free states, than the DOTA complexes. PMID:20722424

  7. Input estimation from measured structural response

    SciTech Connect

    Harvey, Dustin; Cross, Elizabeth; Silva, Ramon A; Farrar, Charles R; Bement, Matt

    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.

  8. 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.

  9. In Acute Stroke, Can CT Perfusion-Derived Cerebral Blood Volume Maps Substitute for Diffusion-Weighted Imaging in Identifying the Ischemic Core?

    PubMed Central

    Copen, William A.; Morais, Livia T.; Wu, Ona; Schwamm, Lee H.; Schaefer, Pamela W.; González, R. Gilberto; Yoo, Albert J.

    2015-01-01

    Background and Purpose In the treatment of patients with suspected acute ischemic stroke, increasing evidence suggests the importance of measuring the volume of the irreversibly injured “ischemic core.” The gold standard method for doing this in the clinical setting is diffusion-weighted magnetic resonance imaging (DWI), but many authors suggest that maps of regional cerebral blood volume (CBV) derived from computed tomography perfusion imaging (CTP) can substitute for DWI. We sought to determine whether DWI and CTP-derived CBV maps are equivalent in measuring core volume. Methods 58 patients with suspected stroke underwent CTP and DWI within 6 hours of symptom onset. We measured low-CBV lesion volumes using three methods: “objective absolute,” i.e. the volume of tissue with CBV below each of six published absolute thresholds (0.9–2.5 mL/100 g), “objective relative,” whose six thresholds (51%-60%) were fractions of mean contralateral CBV, and “subjective,” in which two radiologists (R1, R2) outlined lesions subjectively. We assessed the sensitivity and specificity of each method, threshold, and radiologist in detecting infarction, and the degree to which each over- or underestimated the DWI core volume. Additionally, in the subset of 32 patients for whom follow-up CT or MRI was available, we measured the proportion of CBV- or DWI-defined core lesions that exceeded the follow-up infarct volume, and the maximum amount by which this occurred. Results DWI was positive in 72% (42/58) of patients. CBV maps’ sensitivity/specificity in identifying DWI-positive patients were 100%/0% for both objective methods with all thresholds, 43%/94% for R1, and 83%/44% for R2. Mean core overestimation was 156–699 mL for objective absolute thresholds, and 127–200 mL for objective relative thresholds. For R1 and R2, respectively, mean±SD subjective overestimation were -11±26 mL and -11±23 mL, but subjective volumes differed from DWI volumes by up to 117 and 124 mL in individual patients. Inter-rater agreement regarding the presence of infarction on CBV maps was poor (kappa = 0.21). Core lesions defined by the six objective absolute CBV thresholds exceeded follow-up infarct volumes for 81%-100% of patients, by up to 430–1002 mL. Core estimates produced by objective relative thresholds exceeded follow-up volumes in 91% of patients, by up to 210-280 mL. Subjective lesions defined by R1 and R2 exceeded follow-up volumes in 18% and 26% of cases, by up to 71 and 15 mL, respectively. Only 1 of 23 DWI lesions (4%) exceeded final infarct volume, by 3 mL. Conclusion CTP-derived CBV maps cannot reliably substitute for DWI in measuring core volume, or even establish which patients have DWI lesions. PMID:26193486

  10. Input apparatus for dynamic signature verification systems

    DOEpatents

    EerNisse, Errol P.; Land, Cecil E.; Snelling, Jay B.

    1978-01-01

    The disclosure relates to signature verification input apparatus comprising a writing instrument and platen containing piezoelectric transducers which generate signals in response to writing pressures.

  11. Performance evaluation of input and output queueing techniques in ATM switching systems

    NASA Astrophysics Data System (ADS)

    Delre, Enrico; Fantacci, Romano

    1993-10-01

    In this paper, alternatives to model a fast packet switching system are analyzed. A nonblocking switch fabric which runs at the same speed as the input/output links is considered. The performance of the considered approaches have been derived by theoretical analysis and computer simulations. Performance comparison between input queueing approaches with different selection policies are presented. Novel input and output queueing techniques are also proposed. In particular it is shown that, depending on the implementation, the novel input queueing approach studied in this paper achieves the same performance as the optimum (output) queueing alternative, without resorting to a faster packet switch fabric.

  12. Using model order tests to determine sensory inputs in a motion study

    NASA Technical Reports Server (NTRS)

    Repperger, D. W.; Junker, A. M.

    1977-01-01

    In the study of motion effects on tracking performance, a problem of interest is the determination of what sensory inputs a human uses in controlling his tracking task. In the approach presented here a simple canonical model (FID or a proportional, integral, derivative structure) is used to model the human's input-output time series. A study of significant changes in reduction of the output error loss functional is conducted as different permutations of parameters are considered. Since this canonical model includes parameters which are related to inputs to the human (such as the error signal, its derivatives and integration), the study of model order is equivalent to the study of which sensory inputs are being used by the tracker. The parameters are obtained which have the greatest effect on reducing the loss function significantly. In this manner the identification procedure converts the problem of testing for model order into the problem of determining sensory inputs.

  13. A hyperspectral image analysis workbench for environmental science applications

    SciTech Connect

    Christiansen, J.H.; Zawada, D.G.; Simunich, K.L.; Slater, J.C.

    1992-10-01

    A significant challenge to the information sciences is to provide more powerful and accessible means to exploit the enormous wealth of data available from high-resolution imaging spectrometry, or ``hyperspectral`` imagery, for analysis, for mapping purposes, and for input to environmental modeling applications. As an initial response to this challenge, Argonne`s Advanced Computer Applications Center has developed a workstation-based prototype software workbench which employs Al techniques and other advanced approaches to deduce surface characteristics and extract features from the hyperspectral images. Among its current capabilities, the prototype system can classify pixels by abstract surface type. The classification process employs neural network analysis of inputs which include pixel spectra and a variety of processed image metrics, including image ``texture spectra`` derived from fractal signatures computed for subimage tiles at each wavelength.

  14. A hyperspectral image analysis workbench for environmental science applications

    SciTech Connect

    Christiansen, J.H.; Zawada, D.G.; Simunich, K.L.; Slater, J.C.

    1992-01-01

    A significant challenge to the information sciences is to provide more powerful and accessible means to exploit the enormous wealth of data available from high-resolution imaging spectrometry, or hyperspectral'' imagery, for analysis, for mapping purposes, and for input to environmental modeling applications. As an initial response to this challenge, Argonne's Advanced Computer Applications Center has developed a workstation-based prototype software workbench which employs Al techniques and other advanced approaches to deduce surface characteristics and extract features from the hyperspectral images. Among its current capabilities, the prototype system can classify pixels by abstract surface type. The classification process employs neural network analysis of inputs which include pixel spectra and a variety of processed image metrics, including image texture spectra'' derived from fractal signatures computed for subimage tiles at each wavelength.

  15. Managing Input during Assistive Technology Product Design

    ERIC Educational Resources Information Center

    Choi, Young Mi

    2011-01-01

    Many different sources of input are available to assistive technology innovators during the course of designing products. However, there is little information on which ones may be most effective or how they may be efficiently utilized within the design process. The aim of this project was to compare how three types of input--from simulation tools,…

  16. Input Effects within a Constructionist Framework

    ERIC Educational Resources Information Center

    Boyd, Jeremy K.; Goldberg, Adele E.

    2009-01-01

    Constructionist approaches to language hypothesize that grammar can be learned from the input using domain-general mechanisms. This emphasis has engendered a great deal of research--exemplified in the present issue--that seeks to illuminate the ways in which input-related factors can both drive and constrain constructional acquisition. In this…

  17. Modality of Input and Vocabulary Acquisition

    ERIC Educational Resources Information Center

    Sydorenko, Tetyana

    2010-01-01

    This study examines the effect of input modality (video, audio, and captions, i.e., on-screen text in the same language as audio) on (a) the learning of written and aural word forms, (b) overall vocabulary gains, (c) attention to input, and (d) vocabulary learning strategies of beginning L2 learners. Twenty-six second-semester learners of Russian

  18. 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…

  19. 39 CFR 3020.92 - Public input.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 39 Postal Service 1 2014-07-01 2014-07-01 false Public input. 3020.92 Section 3020.92 Postal Service POSTAL REGULATORY COMMISSION PERSONNEL PRODUCT LISTS Requests Initiated by the Postal Service to Change the Mail Classification Schedule § 3020.92 Public input. The Commission shall publish...

  20. 39 CFR 3020.92 - Public input.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 39 Postal Service 1 2013-07-01 2013-07-01 false Public input. 3020.92 Section 3020.92 Postal Service POSTAL REGULATORY COMMISSION PERSONNEL PRODUCT LISTS Requests Initiated by the Postal Service to Change the Mail Classification Schedule § 3020.92 Public input. The Commission shall publish...

  1. 39 CFR 3020.92 - Public input.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 39 Postal Service 1 2012-07-01 2012-07-01 false Public input. 3020.92 Section 3020.92 Postal Service POSTAL REGULATORY COMMISSION PERSONNEL PRODUCT LISTS Requests Initiated by the Postal Service to Change the Mail Classification Schedule § 3020.92 Public input. The Commission shall publish...

  2. 39 CFR 3020.92 - Public input.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 39 Postal Service 1 2011-07-01 2011-07-01 false Public input. 3020.92 Section 3020.92 Postal Service POSTAL REGULATORY COMMISSION PERSONNEL PRODUCT LISTS Requests Initiated by the Postal Service to Change the Mail Classification Schedule § 3020.92 Public input. The Commission shall publish...

  3. Modality of Input and Vocabulary Acquisition

    ERIC Educational Resources Information Center

    Sydorenko, Tetyana

    2010-01-01

    This study examines the effect of input modality (video, audio, and captions, i.e., on-screen text in the same language as audio) on (a) the learning of written and aural word forms, (b) overall vocabulary gains, (c) attention to input, and (d) vocabulary learning strategies of beginning L2 learners. Twenty-six second-semester learners of Russian…

  4. Response of traveling waves to transient inputs in neural fields

    NASA Astrophysics Data System (ADS)

    Kilpatrick, Zachary P.; Ermentrout, Bard

    2012-02-01

    We analyze the effects of transient stimulation on traveling waves in neural field equations. Neural fields are modeled as integro-differential equations whose convolution term represents the synaptic connections of a spatially extended neuronal network. The adjoint of the linearized wave equation can be used to identify how a particular input will shift the location of a traveling wave. This wave response function is analogous to the phase response curve of limit cycle oscillators. For traveling fronts in an excitatory network, the sign of the shift depends solely on the sign of the transient input. A complementary estimate of the effective shift is derived using an equation for the time-dependent speed of the perturbed front. Traveling pulses are analyzed in an asymmetric lateral inhibitory network and they can be advanced or delayed, depending on the position of spatially localized transient inputs. We also develop bounds on the amplitude of transient input necessary to terminate traveling pulses, based on the global bifurcation structure of the neural field.

  5. 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.

  6. Pulmonary Arterial Hypertension: MR Imaging-derived First-Pass Bolus Kinetic Parameters Are Biomarkers for Pulmonary Hemodynamics, Cardiac Function, and Ventricular Remodeling

    PubMed Central

    Skrok, Jan; Shehata, Monda L.; Mathai, Stephen; Girgis, Reda E.; Zaiman, Ari; Mudd, James O.; Boyce, Danielle; Lechtzin, Noah; Lima, João A. C.; Bluemke, David A.; Hassoun, Paul M.

    2012-01-01

    Purpose: To prospectively compare contrast material–enhanced (CE) magnetic resonance (MR) imaging–derived right-to-left ventricle pulmonary transit time (PTT), left ventricular (LV) full width at half maximum (FWHM), and LV time to peak (TTP) between patients with pulmonary arterial hypertension (PAH) and healthy volunteers and to correlate these measurements with survival markers in patients with PAH. Materials and Methods: This HIPAA-compliant study received institutional review board approval. Written informed consent was obtained from all participants. Forty-three patients (32 with PAH [29 women; median age, 55.4 years], 11 with scleroderma but not PAH [seven women; median age, 58.9 years]) underwent right-sided heart catheterization and 3-T CE cardiac MR imaging. Eighteen age- and sex-matched healthy control subjects (12 women; median age, 51.7 years) underwent only CE MR imaging. A short-axis saturation-recovery gradient-echo section was acquired in the basal third of both ventricles, and right-to-left-ventricle PTT, LV FWHM, and LV TTP were calculated. Statistical analysis included Kruskal-Wallis test, Wilcoxon rank sum test, Spearman correlation coefficient, multiple linear regression analysis, and Lin correlation coefficient analysis. Results: Patients had significantly longer PTT (median, 8.2 seconds; 25th–75th percentile, 6.9–9.9 seconds), FWHM (median, 8.2 seconds; 25th–75th percentile, 5.7–11.4 seconds), and TTP (median, 4.8 seconds; 25th–75th percentile, 3.9–6.5 seconds) than did control subjects (median, 6.4 seconds; 25th–75th percentile, 5.7–7.1 seconds; median, 5.2 seconds; 25th–75th percentile, 4.1–6.1 seconds; median, 3.2 seconds; 25th–75th percentile, 2.8–3.8 seconds, respectively; P < .01 for each) and subjects with scleroderma but not PAH (median, 6.5 seconds; 25th–75th percentile, 5.6–7.0 seconds; median, 5.0 seconds; 25th–75th percentile, 4.0–7.3 seconds; median, 3.6 seconds; 25th–75th percentile, 2.7–4.0 seconds, respectively; P < .02 for each). PTT, LV FWHM, and LV TTP correlated with pulmonary vascular resistance index (P < .01), right ventricular stroke volume index (P ≤ .01), and pulmonary artery capacitance (P ≤ .02). In multiple linear regression models, PTT, FWHM, and TTP were associated with mean pulmonary arterial pressure and cardiac index. Conclusion: CE MR-derived PTT, LV FWHM, and LV TTP are noninvasive compound markers of pulmonary hemodynamics and cardiac function in patients with PAH. Their predictive value for patient outcome warrants further investigation. © RSNA, 2012 Supplemental materialhttp://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.12111001/-/DC1 PMID:22509050

  7. Comparison of image derived, measured and modeled SWE in relation to snow-melt runoff for the Senator Beck basin, CO during the spring of 2010

    NASA Astrophysics Data System (ADS)

    Frankenstein, S.; Deeb, E. J.; Koenig, G. G.

    2010-12-01

    Strong correlation between passive microwave derived snow ripening and the onset of snowmelt flooding was found in several very large basins in Alaska and Yukon Territory where pixel heterogeneity is limited. These studies did not investigate either the impact of subpixel heterogeneity on microwave sensor observations or the factors responsible for the lag between the onset of snowmelt and increased stream flow. To help us address these questions we compare modeled snow extent and SWE against ground-, air-, and space-based measurements. The snow model we used is part of the land surface model FASST (Fast All-season Soil Strength). In April of this year an intensive ground truth campaign was conducted in coordination with several ground-, air-,and space-based image acquisitions including hyperspectral (AVIRIS and field spectroscopy), multispectral (MODIS), laser (ground-based scanning LiDAR), active (C- and X-Band radar) and passive (SSM/I and AMSR-E) microwave systems in the Senator Beck basin. The basin is located in the San Juan mountains of Southwest Colorado. It has been used as an intense snow study area since 2004 and is characterized as sub-alpine to alpine with mixed vegetation. Part of the permanent instrumentation includes three stream gauges and two meteorological stations. Using this mixed, rich data set we begin to quantify the terrain and meteorological mechanisms responsible for the observed lag between the onset of snowmelt and increased stream flow as well as enhancing our ability to predict SWE in remote, heterogeneous regions. The next step is to test our findings in other basins.

  8. Measuring Input Thresholds on an Existing Board

    NASA Technical Reports Server (NTRS)

    Kuperman, Igor; Gutrich, Daniel G.; Berkun, Andrew C.

    2011-01-01

    A critical PECL (positive emitter-coupled logic) interface to Xilinx interface needed to be changed on an existing flight board. The new Xilinx input interface used a CMOS (complementary metal-oxide semiconductor) type of input, and the driver could meet its thresholds typically, but not in worst-case, according to the data sheet. The previous interface had been based on comparison with an external reference, but the CMOS input is based on comparison with an internal divider from the power supply. A way to measure what the exact input threshold was for this device for 64 inputs on a flight board was needed. The measurement technique allowed an accurate measurement of the voltage required to switch a Xilinx input from high to low for each of the 64 lines, while only probing two of them. Directly driving an external voltage was considered too risky, and tests done on any other unit could not be used to qualify the flight board. The two lines directly probed gave an absolute voltage threshold calibration, while data collected on the remaining 62 lines without probing gave relative measurements that could be used to identify any outliers. The PECL interface was forced to a long-period square wave by driving a saturated square wave into the ADC (analog to digital converter). The active pull-down circuit was turned off, causing each line to rise rapidly and fall slowly according to the input s weak pull-down circuitry. The fall time shows up as a change in the pulse width of the signal ready by the Xilinx. This change in pulse width is a function of capacitance, pulldown current, and input threshold. Capacitance was known from the different trace lengths, plus a gate input capacitance, which is the same for all inputs. The pull-down current is the same for all inputs including the two that are probed directly. The data was combined, and the Excel solver tool was used to find input thresholds for the 62 lines. This was repeated over different supply voltages and temperatures to show that the interface had voltage margin under all worst case conditions. Gate input thresholds are normally measured at the manufacturer when the device is on a chip tester. A key function of this machine was duplicated on an existing flight board with no modifications to the nets to be tested, with the exception of changes in the FPGA program.

  9. Single-image phase retrieval using an edge illumination X-ray phase-contrast imaging setup

    PubMed Central

    Diemoz, Paul C.; Vittoria, Fabio A.; Hagen, Charlotte K.; Endrizzi, Marco; Coan, Paola; Brun, Emmanuel; Wagner, Ulrich H.; Rau, Christoph; Robinson, Ian K.; Bravin, Alberto; Olivo, Alessandro

    2015-01-01

    A method is proposed which enables the retrieval of the thickness or of the projected electron density of a sample from a single input image acquired with an edge illumination phase-contrast imaging setup. The method assumes the case of a quasi-homogeneous sample, i.e. a sample with a constant ratio between the real and imaginary parts of its complex refractive index. Compared with current methods based on combining two edge illumination images acquired in different configurations of the setup, this new approach presents advantages in terms of simplicity of acquisition procedure and shorter data collection time, which are very important especially for applications such as computed tomography and dynamical imaging. Furthermore, the fact that phase information is directly extracted, instead of its derivative, can enable a simpler image interpretation and be beneficial for subsequent processing such as segmentation. The method is first theoretically derived and its conditions of applicability defined. Quantitative accuracy in the case of homogeneous objects as well as enhanced image quality for the imaging of complex biological samples are demonstrated through experiments at two synchrotron radiation facilities. The large range of applicability, the robustness against noise and the need for only one input image suggest a high potential for investigations in various research subjects. PMID:26134813

  10. Single-image phase retrieval using an edge illumination X-ray phase-contrast imaging setup.

    PubMed

    Diemoz, Paul C; Vittoria, Fabio A; Hagen, Charlotte K; Endrizzi, Marco; Coan, Paola; Brun, Emmanuel; Wagner, Ulrich H; Rau, Christoph; Robinson, Ian K; Bravin, Alberto; Olivo, Alessandro

    2015-07-01

    A method is proposed which enables the retrieval of the thickness or of the projected electron density of a sample from a single input image acquired with an edge illumination phase-contrast imaging setup. The method assumes the case of a quasi-homogeneous sample, i.e. a sample with a constant ratio between the real and imaginary parts of its complex refractive index. Compared with current methods based on combining two edge illumination images acquired in different configurations of the setup, this new approach presents advantages in terms of simplicity of acquisition procedure and shorter data collection time, which are very important especially for applications such as computed tomography and dynamical imaging. Furthermore, the fact that phase information is directly extracted, instead of its derivative, can enable a simpler image interpretation and be beneficial for subsequent processing such as segmentation. The method is first theoretically derived and its conditions of applicability defined. Quantitative accuracy in the case of homogeneous objects as well as enhanced image quality for the imaging of complex biological samples are demonstrated through experiments at two synchrotron radiation facilities. The large range of applicability, the robustness against noise and the need for only one input image suggest a high potential for investigations in various research subjects. PMID:26134813

  11. Input-shaped actuation of electromagnetic MEMS mirrors

    NASA Astrophysics Data System (ADS)

    Reitterer, Jrg; Fidler, Franz; Schmid, Gerhard; Hambeck, Christian; Saint Julien-Wallsee, Ferdinand; Leeb, Walter; Schmid, Ulrich

    2015-05-01

    For many applications of MEMS actuators a well-defined trajectory of the movable device component is crucial when using a simple and inexpensive open-loop controller. We have applied to quasi-statically actuated electromagnetic MEMS mirrors the control technique called "input shaping", which is widely used for systems at the macro-scale and to a lesser extent also to systems at the micro-scale. We derive the impulse response of a filter which suppresses the excitation of undesired resonant modes and present simulation and measurement results of the oscillation-free linear MEMS mirror movement. The robustness of different input shaping filter types with respect to errors in the estimation of the system parameters, i.e., resonance frequency and damping ratio, is analyzed.

  12. 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.

  13. High Temporal Resolution Dynamic MRI and Arterial Input Function for Assessment of GFR in Pediatric Subjects

    PubMed Central

    Yoruk, Umit; Saranathan, Manojkumar; Loening, Andreas M; Hargreaves, Brian A; Vasanawala, Shreyas S

    2015-01-01

    Purpose To introduce a respiratory-gated high-spatiotemporal-resolution dynamic-contrast-enhanced MRI technique and a high-temporal-resolution aortic input function (HTR-AIF) estimation method for glomerular filtration rate (GFR) assessment in children. Methods A high-spatiotemporal-resolution DCE-MRI method with view-shared reconstruction was modified to incorporate respiratory-gating, and an AIF estimation method that uses a fraction of the k-space data from each respiratory period was developed (HTR-AIF). The method was validated using realistic digital phantom simulations and demonstrated on clinical subjects. The GFR estimates using HTR-AIF were compared to estimates obtained by using an AIF derived directly from the view-shared images. Results Digital phantom simulations showed that using the HTR-AIF technique gives more accurate AIF estimates (RMSE = 0.0932) compared to the existing estimation method (RMSE = 0.2059) that used view-sharing (VS). For simulated GFR > 27 ml/min, GFR estimation error was between 32% and 17% using view-shared AIF, whereas estimation error was less than 10% using HTR-AIF. In all clinical subjects, the HTR-AIF method resulted in higher GFR estimations than the view-shared method. Conclusion The HTR-AIF method improves the accuracy of both the AIF and GFR estimates derived from the respiratory-gated acquisitions, and makes GFR estimation feasible in free-breathing pediatric subjects. PMID:25946307

  14. Wireless, relative-motion computer input device

    DOEpatents

    Holzrichter, John F.; Rosenbury, Erwin T.

    2004-05-18

    The present invention provides a system for controlling a computer display in a workspace using an input unit/output unit. A train of EM waves are sent out to flood the workspace. EM waves are reflected from the input unit/output unit. A relative distance moved information signal is created using the EM waves that are reflected from the input unit/output unit. Algorithms are used to convert the relative distance moved information signal to a display signal. The computer display is controlled in response to the display signal.

  15. Optical input impedance of nanostrip antennas

    NASA Astrophysics Data System (ADS)

    Wang, Ivan; Du, Ya-ping

    2012-05-01

    We conduct an investigation into optical nanoantennas in the form of a strip dipole made from aluminum. With the finite-difference time domain simulation both optical input impedance and radiation efficiency of nanostrip antennas are addressed. An equivalent circuit is presented as well for the nanostrip antennas at optical resonances. The optical input resistance can be adjusted by varying the geometric parameters of antenna strips. By changing both strip area and strip length simultaneously, optical input resistance can be adjusted for matching impedance with an external feeding or loading circuit. It is found that the optical radiation efficiency does not change significantly when the size of a nanostrip antenna varies moderately.

  16. 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.

  17. 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.

  18. 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.

  19. Feature maps driven no-reference image quality prediction of authentically distorted images

    NASA Astrophysics Data System (ADS)

    Ghadiyaram, Deepti; Bovik, Alan C.

    2015-03-01

    Current blind image quality prediction models rely on benchmark databases comprised of singly and synthetically distorted images, thereby learning image features that are only adequate to predict human perceived visual quality on such inauthentic distortions. However, real world images often contain complex mixtures of multiple distortions. Rather than a) discounting the effect of these mixtures of distortions on an image's perceptual quality and considering only the dominant distortion or b) using features that are only proven to be efficient for singly distorted images, we deeply study the natural scene statistics of authentically distorted images, in different color spaces and transform domains. We propose a feature-maps-driven statistical approach which avoids any latent assumptions about the type of distortion(s) contained in an image, and focuses instead on modeling the remarkable consistencies in the scene statistics of real world images in the absence of distortions. We design a deep belief network that takes model-based statistical image features derived from a very large database of authentically distorted images as input and discovers good feature representations by generalizing over different distortion types, mixtures, and severities, which are later used to learn a regressor for quality prediction. We demonstrate the remarkable competence of our features for improving automatic perceptual quality prediction on a benchmark database and on the newly designed LIVE Authentic Image Quality Challenge Database and show that our approach of combining robust statistical features and the deep belief network dramatically outperforms the state-of-the-art.

  20. Micromachined dual input axis rate gyroscope

    NASA Astrophysics Data System (ADS)

    Juneau, Thor Nelson

    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, contrasting approach based on angular resonance of a rotating rigid rotor suspended by torsional springs. The inherent symmetry of the circular design allows angular rate measurement about two axes simultaneously, hence the name micromachined dual-axis rate gyroscope. The underlying theory of operation, mechanical structure design optimization, electrical interface circuitry, and signal processing are described in detail. Several operational versions were fabricated using two different fully integrated surface micromachining processes as proof of concept. The heart of the dual-axis rate gyroscope is a ˜2 mum thick polysilicon disk or rotor suspended above the substrate by a four beam suspension. When this rotor in driven into angular oscillation about the axis perpendicular to the substrate, a rotation rate about the two axes parallel to the substrate invokes an out of plane rotor tilting motion due to Coriolis acceleration. This tilting motion is capacitively measured and on board integrated signal processing provides two output voltages proportional to angular rate input about the two axes parallel to the substrate. The design process begins with the derivation of gyroscopic dynamics. The equations suggest that tuning sense mode frequencies to the drive oscillation frequency can vastly increase mechanical sensitivity. Hence the supporting four beam suspension is designed such that electrostatic tuning can match modes despite process variations. The electrostatic tuning range is limited only by rotor collapse to the substrate when tuning-voltage induced electrostatic forces over power the beam suspension. Multivariable design optimization is used to maximize performance given process constraints. All electronics needed to sustain rotor oscillation, control oscillation amplitude, sense rotor tilting due to Coriolis acceleration, and process sense signals to produce voltage outputs are explained. A voltage controlled oscillator slaved to the structure oscillation through a phase-lock-loop is used as the master clock to produce all signals needed for signal processing and amplitude control. Thus, the micromachine serves as both a rotation sensor and a frequency reference. Final versions fabricated by Sandia National Laboratory were fully integrated and therefore required only passive components and electrical sources off-chip. Without electrostatic tuning, dual-axis rate gyroscopes achieved 0.1sp°/sec/sqrt{Hz} noise level. This provided automotive grade performance of approximately 1sp°/sec noise floor over a 100 Hz bandwidth. Electrical tuning decreased noise to below 0.02sp°/sec/sqrt{Hz}. However, open-loop operation with nearly matched sense and drive modes can result in higher cross-axis sensitivity, scale factor drift, and phase errors. Closed-loop feedback methods which alleviate these problems as well as reduce offset drift due to quadrature error are presented as future directions.

  1. Spectral reproduction from scene to hardcopy: II. Image processing

    NASA Astrophysics Data System (ADS)

    Rosen, Mitchell; Imai, Francisco H.; Jiang, Xiaoyun; Ohta, Noboru

    2000-12-01

    Traditional image processing techniques used for 3- and 4- band images are not suited to the many-band character of spectral images. A sparse multi-dimensional lookup table with inter-node interpolation is a typical image processing technique used for applying either a known model or an empirically derived mapping to an image. Such an approach for spectral images becomes problematic because input dimensionality of lookup tables is proportional to the number of source image bands and the size of lookup table sis exponentially related to the number of input dimensions. While an RGB or CMY source images would require a 3D lookup table, a 31-band spectral image would need a 31-dimensional lookup table. A 31-dimensional lookup table would be absurdly large. A novel approach to spectral image processing is explored. This approach combines a low-cost spectral analysis followed by application of one from a set of low-dimensional lookup tables. The method is computationally feasible and does not make excessive demands on disk space or run-time memory.

  2. 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.

  3. Synthesis and evaluation of (18)F-labeled 4-nitrobenzyl derivatives for imaging tumor hypoxia with positron emission tomography: Comparison of 2-[(18)F]fluoroethyl carbonate and 2-[(18)F]fluoroethyl carbamate.

    PubMed

    Zhang, Zhengxing; Lau, Joseph; Kuo, Hsiou-Ting; Zhang, Chengcheng; Hundal-Jabal, Navjit; Colpo, Nadine; Bénard, François; Lin, Kuo-Shyan

    2016-01-15

    Two 4-nitrobenzyl derivatives, 2-fluoroethyl 4-nitrobenzyl carbonate 1 and 4-nitrobenzyl N-2-fluoroethyl carbamate 2, were radiolabeled with (18)F and evaluated for imaging tumor hypoxia with positron emission tomography. Although good tumor uptake was observed for [(18)F]1 and [(18)F]2 (>2.5%ID/g at 3-h post-injection), the tracers cleared slowly from nontarget tissues (>1.5%ID/g) and exhibited extensive defluorination in vivo (>4.0%ID/g for bone). Therefore, [(18)F]1 and [(18)F]2 are not suitable for imaging tumor hypoxia due to suboptimal tumor-to-background contrasts. PMID:26646218

  4. Scaling of global input-output networks

    NASA Astrophysics Data System (ADS)

    Liang, Sai; Qi, Zhengling; Qu, Shen; Zhu, Ji; Chiu, Anthony S. F.; Jia, Xiaoping; Xu, Ming

    2016-06-01

    Examining scaling patterns of networks can help understand how structural features relate to the behavior of the networks. Input-output networks consist of industries as nodes and inter-industrial exchanges of products as links. Previous studies consider limited measures for node strengths and link weights, and also ignore the impact of dataset choice. We consider a comprehensive set of indicators in this study that are important in economic analysis, and also examine the impact of dataset choice, by studying input-output networks in individual countries and the entire world. Results show that Burr, Log-Logistic, Log-normal, and Weibull distributions can better describe scaling patterns of global input-output networks. We also find that dataset choice has limited impacts on the observed scaling patterns. Our findings can help examine the quality of economic statistics, estimate missing data in economic statistics, and identify key nodes and links in input-output networks to support economic policymaking.

  5. Adaptive input filter compensation for switching regulators

    NASA Astrophysics Data System (ADS)

    Kelkar, S. S.; Lee, F. C.

    1984-01-01

    An input filter is frequently employed between a switching regulator and its power source. However, its presence often results in degradation of dynamic performances and stability. The detrimental interaction is between an input filter and a switching regulator and is a function of the input filter parameters and also of the supply voltage. An earlier paper presented an analysis and design procedure aimed at developing a feed-forward loop to cancel this undesirable interaction. The feed-forward design is extended here to encompass a scheme that automatically accounts for changes in the supply voltage; the result is an adaptive compensation that tracks the input voltage variations. Experimental results are presented that confirm the adaptive nature of the design.

  6. 39 CFR 3020.92 - Public input.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Change the Mail Classification Schedule § 3020.92 Public input. The Commission shall publish Postal... opportunity to comment on whether the planned changes are inconsistent with 39 U.S.C. 3642....

  7. Kernel principal component analysis for stochastic input model generation

    SciTech Connect

    Ma Xiang; Zabaras, Nicholas

    2011-08-10

    Highlights: {yields} KPCA is used to construct a reduced order stochastic model of permeability. {yields} A new approach is proposed to solve the pre-image problem in KPCA. {yields} Polynomial chaos is used to provide a parametric stochastic input model. {yields} Flow in porous media with channelized permeability is considered. - Abstract: Stochastic analysis of random heterogeneous media provides useful information only if realistic input models of the material property variations are used. These input models are often constructed from a set of experimental samples of the underlying random field. To this end, the Karhunen-Loeve (K-L) expansion, also known as principal component analysis (PCA), is the most popular model reduction method due to its uniform mean-square convergence. However, it only projects the samples onto an optimal linear subspace, which results in an unreasonable representation of the original data if they are non-linearly related to each other. In other words, it only preserves the first-order (mean) and second-order statistics (covariance) of a random field, which is insufficient for reproducing complex structures. This paper applies kernel principal component analysis (KPCA) to construct a reduced-order stochastic input model for the material property variation in heterogeneous media. KPCA can be considered as a nonlinear version of PCA. Through use of kernel functions, KPCA further enables the preservation of higher-order statistics of the random field, instead of just two-point statistics as in the standard Karhunen-Loeve (K-L) expansion. Thus, this method can model non-Gaussian, non-stationary random fields. In this work, we also propose a new approach to solve the pre-image problem involved in KPCA. In addition, polynomial chaos (PC) expansion is used to represent the random coefficients in KPCA which provides a parametric stochastic input model. Thus, realizations, which are statistically consistent with the experimental data, can be generated in an efficient way. We showcase the methodology by constructing a low-dimensional stochastic input model to represent channelized permeability in porous media.

  8. 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.

  9. Significance of Input Correlations in Striatal Function

    PubMed Central

    Yim, Man Yi; Aertsen, Ad; Kumar, Arvind

    2011-01-01

    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

  10. 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.

  11. 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

  12. A new synthesis for terrestrial nitrogen inputs

    NASA Astrophysics Data System (ADS)

    Houlton, B. Z.; Morford, S. L.

    2015-04-01

    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 explicitly considers both rock and atmospheric sources of N. We review evidence for state-factor regulation over biological fixation, deposition, and rock-weathering inputs from local to global scales and in transient vs. steady-state landscapes. Our investigation 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., the 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, non-symmetrical feedbacks among input pathways in which high N inputs via deposition or rock-weathering sources have the potential to reduce biological fixation rates mark N as fundamentally different from other nutrients. The new synthesis for terrestrial N inputs provides a novel set of research issues and opportunities in the multidisciplinary Earth system sciences, with implications for patterns of N limitation, tectonic controls over biogeochemical cycling, and carbon-nutrient-climate interactions.

  13. 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.

  14. Noise facilitates transcriptional control under dynamic inputs.

    PubMed

    Kellogg, Ryan A; Tay, Savaş

    2015-01-29

    Cells must respond sensitively to time-varying inputs in complex signaling environments. To understand how signaling networks process dynamic inputs into gene expression outputs and the role of noise in cellular information processing, we studied the immune pathway NF-κB under periodic cytokine inputs using microfluidic single-cell measurements and stochastic modeling. We find that NF-κB dynamics in fibroblasts synchronize with oscillating TNF signal and become entrained, leading to significantly increased NF-κB oscillation amplitude and mRNA output compared to non-entrained response. Simulations show that intrinsic biochemical noise in individual cells improves NF-κB oscillation and entrainment, whereas cell-to-cell variability in NF-κB natural frequency creates population robustness, together enabling entrainment over a wider range of dynamic inputs. This wide range is confirmed by experiments where entrained cells were measured under all input periods. These results indicate that synergy between oscillation and noise allows cells to achieve efficient gene expression in dynamically changing signaling environments. PMID:25635454

  15. Six axis force feedback input device

    NASA Technical Reports Server (NTRS)

    Ohm, Timothy (Inventor)

    1998-01-01

    The present invention is a low friction, low inertia, six-axis force feedback input device comprising an arm with double-jointed, tendon-driven revolute joints, a decoupled tendon-driven wrist, and a base with encoders and motors. The input device functions as a master robot manipulator of a microsurgical teleoperated robot system including a slave robot manipulator coupled to an amplifier chassis, which is coupled to a control chassis, which is coupled to a workstation with a graphical user interface. The amplifier chassis is coupled to the motors of the master robot manipulator and the control chassis is coupled to the encoders of the master robot manipulator. A force feedback can be applied to the input device and can be generated from the slave robot to enable a user to operate the slave robot via the input device without physically viewing the slave robot. Also, the force feedback can be generated from the workstation to represent fictitious forces to constrain the input device's control of the slave robot to be within imaginary predetermined boundaries.

  16. A step-versus-short-pulse input technique to demonstrate acceleration response using an LDV

    NASA Astrophysics Data System (ADS)

    Bruce, Robert A.

    2004-06-01

    This technique for extracting acceleration-like signals from a laser Doppler vibrometer (LDV) depends on comparing the responses of structures to specific impulsive inputs. What is compared here is the derivative-like response of a sufficiently short pulse to that of a step input. This is derivative-like because the pulse itself consists of an abrupt up-thrust followed shortly by an identical, but inverted down-thrust. The short pulse response emulates the negative numerator of the derivative definition in analog fashion. Certain structures excited by long pulses with equal widely-spaced rising and falling step inputs, respond such that the up and down- thrusts responses are exact inverted copies of each other regardless of the structural modes excited. Adjusting this pulse-width to be much smaller than the period of the highest frequency response component forms this derivative responses. Three validation tests are discussed. A consistency check shows the LDV pulse response is close to that of the finite difference scan of the LDV step response. The next test compares LDV pulse responses relative to differing input pulse-widths. The last test correlates the step input response of a mounted accelerometer on a test fixture to that of the pulse input response of an LDV focused on top. This technique should be helpful in comparing the LDV-to-accelerometer responses in mechanical setups where this derivative character of impulse inputs is valid. Since this comparison encompasses multiple excited modes, one can check or validate device calibrations at these different frequencies. It may be useful in some tests as an analog means of simulating acceleration using the velocity output of a no-mass-load LDV.

  17. Computer Generated Inputs for NMIS Processor Verification

    SciTech Connect

    J. A. Mullens; J. E. Breeding; J. A. McEvers; R. W. Wysor; L. G. Chiang; J. R. Lenarduzzi; J. T. Mihalczo; J. K. Mattingly

    2001-06-29

    Proper operation of the Nuclear Identification Materials System (NMIS) processor can be verified using computer-generated inputs [BIST (Built-In-Self-Test)] at the digital inputs. Preselected sequences of input pulses to all channels with known correlation functions are compared to the output of the processor. These types of verifications have been utilized in NMIS type correlation processors at the Oak Ridge National Laboratory since 1984. The use of this test confirmed a malfunction in a NMIS processor at the All-Russian Scientific Research Institute of Experimental Physics (VNIIEF) in 1998. The NMIS processor boards were returned to the U.S. for repair and subsequently used in NMIS passive and active measurements with Pu at VNIIEF in 1999.