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Sample records for partial volume correction

  1. Partial Volume Effects correction in emission tomography

    International Nuclear Information System (INIS)

    Le Pogam, Adrien

    2010-01-01

    Partial Volume Effects (PVE) designates the blur commonly found in nuclear medicine images and this PhD work is dedicated to their correction with the objectives of qualitative and quantitative improvement of such images. PVE arise from the limited spatial resolution of functional imaging with either Positron Emission Tomography (PET) or Single Photon Emission Computed Tomography (SPECT). They can be defined as a signal loss in tissues of size similar to the Full Width at Half Maximum (FWHM) of the PSF of the imaging device. In addition, PVE induce activity cross contamination between adjacent structures with different tracer uptakes. This can lead to under or over estimation of the real activity of such analyzed regions. Various methodologies currently exist to compensate or even correct for PVE and they may be classified depending on their place in the processing chain: either before, during or after the image reconstruction process, as well as their dependency on co-registered anatomical images with higher spatial resolution, for instance Computed Tomography (CT) or Magnetic Resonance Imaging (MRI). The voxel-based and post-reconstruction approach was chosen for this work to avoid regions of interest definition and dependency on proprietary reconstruction developed by each manufacturer, in order to improve the PVE correction. Two different contributions were carried out in this work: the first one is based on a multi-resolution methodology in the wavelet domain using the higher resolution details of a co-registered anatomical image associated to the functional dataset to correct. The second one is the improvement of iterative deconvolution based methodologies by using tools such as directional wavelets and curvelets extensions. These various developed approaches were applied and validated using synthetic, simulated and clinical images, for instance with neurology and oncology applications in mind. Finally, as currently available PET/CT scanners incorporate more

  2. Different partial volume correction methods lead to different conclusions

    DEFF Research Database (Denmark)

    Greve, Douglas N; Salat, David H; Bowen, Spencer L

    2016-01-01

    A cross-sectional group study of the effects of aging on brain metabolism as measured with (18)F-FDG-PET was performed using several different partial volume correction (PVC) methods: no correction (NoPVC), Meltzer (MZ), Müller-Gärtner (MG), and the symmetric geometric transfer matrix (SGTM) usin...

  3. SPAM-assisted partial volume correction algorithm for PET

    International Nuclear Information System (INIS)

    Cho, Sung Il; Kang, Keon Wook; Lee, Jae Sung; Lee, Dong Soo; Chung, June Key; Soh, Kwang Sup; Lee, Myung Chul

    2000-01-01

    A probabilistic atlas of the human brain (Statistical Probability Anatomical Maps: SPAM) was developed by the International Consortium for Brain Mapping (ICBM). It will be a good frame for calculating volume of interest (VOI) according to statistical variability of human brain in many fields of brain images. We show that we can get more exact quantification of the counts in VOI by using SPAM in the correlation of partial volume effect for simulated PET image. The MRI of a patient with dementia was segmented into gray matter and white matter, and then they were smoothed to PET resolution. Simulated PET image was made by adding one third of the smoothed white matter to the smoothed gray matter. Spillover effect and partial volume effect were corrected for this simulated PET image with the aid of the segmented and smoothed MR images. The images were spatially normalized to the average brain MRI atlas of ICBM, and were multiplied by the probablities of 98 VOIs of SPAM images of Montreal Neurological Institute. After the correction of partial volume effect, the counts of frontal, partietal, temporal, and occipital lobes were increased by 38±6%, while those of hippocampus and amygdala by 4±3%. By calculating the counts in VOI using the product of probability of SPAM images and counts in the simulated PET image, the counts increase and become closer to the true values. SPAM-assisted partial volume correction is useful for quantification of VOIs in PET images

  4. SPAM-assisted partial volume correction algorithm for PET

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Sung Il; Kang, Keon Wook; Lee, Jae Sung; Lee, Dong Soo; Chung, June Key; Soh, Kwang Sup; Lee, Myung Chul [College of Medicine, Seoul National Univ., Seoul (Korea, Republic of)

    2000-07-01

    A probabilistic atlas of the human brain (Statistical Probability Anatomical Maps: SPAM) was developed by the International Consortium for Brain Mapping (ICBM). It will be a good frame for calculating volume of interest (VOI) according to statistical variability of human brain in many fields of brain images. We show that we can get more exact quantification of the counts in VOI by using SPAM in the correlation of partial volume effect for simulated PET image. The MRI of a patient with dementia was segmented into gray matter and white matter, and then they were smoothed to PET resolution. Simulated PET image was made by adding one third of the smoothed white matter to the smoothed gray matter. Spillover effect and partial volume effect were corrected for this simulated PET image with the aid of the segmented and smoothed MR images. The images were spatially normalized to the average brain MRI atlas of ICBM, and were multiplied by the probablities of 98 VOIs of SPAM images of Montreal Neurological Institute. After the correction of partial volume effect, the counts of frontal, partietal, temporal, and occipital lobes were increased by 38{+-}6%, while those of hippocampus and amygdala by 4{+-}3%. By calculating the counts in VOI using the product of probability of SPAM images and counts in the simulated PET image, the counts increase and become closer to the true values. SPAM-assisted partial volume correction is useful for quantification of VOIs in PET images.

  5. Partial volume correction in SPECT reconstruction with OSEM

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    Erlandsson, Kjell, E-mail: k.erlandsson@ucl.ac.uk [Institute of Nuclear Medicine, University College London and University College London Hospital, London NW1 2BU (United Kingdom); Thomas, Ben; Dickson, John; Hutton, Brian F. [Institute of Nuclear Medicine, University College London and University College London Hospital, London NW1 2BU (United Kingdom)

    2011-08-21

    SPECT images suffer from poor spatial resolution, which leads to partial volume effects due to cross-talk between different anatomical regions. By utilising high-resolution structural images (CT or MRI) it is possible to compensate for these effects. Traditional partial volume correction (PVC) methods suffer from various limitations, such as correcting a single region only, returning only regional mean values, or assuming a stationary point spread function (PSF). We recently presented a novel method in which PVC was combined with the reconstruction process in order to take into account the distance dependent PSF in SPECT, which was based on filtered backprojection (FBP) reconstruction. We now present a new method based on the iterative OSEM algorithm, which has advantageous noise properties compared to FBP. We have applied this method to a series of 10 brain SPECT studies performed on healthy volunteers using the DATSCAN tracer. T1-weighted MRI images were co-registered to the SPECT data and segmented into 33 anatomical regions. The SPECT data were reconstructed using OSEM, and PVC was applied in the projection domain at each iteration. The correction factors were calculated by forward projection of a piece-wise constant image, generated from the segmented MRI. Images were also reconstructed using FBP and standard OSEM with and without resolution recovery (RR) for comparison. The images were evaluated in terms of striatal contrast and regional variability (CoV). The mean striatal contrast obtained with OSEM, OSEM-RR and OSEM-PVC relative to FBP were 1.04, 1.42 and 1.53, respectively, and the mean striatal CoV values are 1.05, 1.53, 1.07. Both OSEM-RR and OSEM-PVC results in images with significantly higher contrast as compared to FBP or OSEM, but OSEM-PVC avoids the increased regional variability of OSEM-RR due to improved structural definition.

  6. Noise suppressed partial volume correction for cardiac SPECT/CT

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    Chan, Chung; Liu, Chi, E-mail: chi.liu@yale.edu [Department of Radiology and Biomedical Imaging, Yale University, New Haven, Connecticut 06520 (United States); Liu, Hui [Department of Radiology and Biomedical Imaging, Yale University, New Haven, Connecticut 06520 and Key Laboratory of Particle and Radiation Imaging (Tsinghua University), Ministry of Education, Beijing 100084 (China); Grobshtein, Yariv [GE Healthcare, Haifa 3910101 (Israel); Stacy, Mitchel R. [Department of Internal Medicine, Yale University, New Haven, Connecticut 06520 (United States); Sinusas, Albert J. [Department of Radiology and Biomedical Imaging, Yale University, New Haven, Connecticut 06520 and Department of Internal Medicine, Yale University, New Haven, Connecticut 06520 (United States)

    2016-09-15

    Purpose: Partial volume correction (PVC) methods typically improve quantification at the expense of increased image noise and reduced reproducibility. In this study, the authors developed a novel voxel-based PVC method that incorporates anatomical knowledge to improve quantification while suppressing noise for cardiac SPECT/CT imaging. Methods: In the proposed method, the SPECT images were first reconstructed using anatomical-based maximum a posteriori (AMAP) with Bowsher’s prior to penalize noise while preserving boundaries. A sequential voxel-by-voxel PVC approach (Yang’s method) was then applied on the AMAP reconstruction using a template response. This template response was obtained by forward projecting a template derived from a contrast-enhanced CT image, and then reconstructed using AMAP to model the partial volume effects (PVEs) introduced by both the system resolution and the smoothing applied during reconstruction. To evaluate the proposed noise suppressed PVC (NS-PVC), the authors first simulated two types of cardiac SPECT studies: a {sup 99m}Tc-tetrofosmin myocardial perfusion scan and a {sup 99m}Tc-labeled red blood cell (RBC) scan on a dedicated cardiac multiple pinhole SPECT/CT at both high and low count levels. The authors then applied the proposed method on a canine equilibrium blood pool study following injection with {sup 99m}Tc-RBCs at different count levels by rebinning the list-mode data into shorter acquisitions. The proposed method was compared to MLEM reconstruction without PVC, two conventional PVC methods, including Yang’s method and multitarget correction (MTC) applied on the MLEM reconstruction, and AMAP reconstruction without PVC. Results: The results showed that the Yang’s method improved quantification, however, yielded increased noise and reduced reproducibility in the regions with higher activity. MTC corrected for PVE on high count data with amplified noise, although yielded the worst performance among all the methods

  7. Anatomically guided voxel-based partial volume effect correction in brain PET : Impact of MRI segmentation

    NARCIS (Netherlands)

    Gutierrez, Daniel; Montandon, Marie-Louise; Assal, Frederic; Allaoua, Mohamed; Ratib, Osman; Loevblad, Karl-Olof; Zaidi, Habib

    2012-01-01

    Partial volume effect is still considered one of the main limitations in brain PET imaging given the limited spatial resolution of current generation PET scanners. The accuracy of anatomically guided partial volume effect correction (PVC) algorithms in brain PET is largely dependent on the

  8. Hitchhiker'S Guide to Voxel Segmentation for Partial Volume Correction of in Vivo Magnetic Resonance Spectroscopy

    Directory of Open Access Journals (Sweden)

    Scott Quadrelli

    2016-01-01

    Full Text Available Partial volume effects have the potential to cause inaccuracies when quantifying metabolites using proton magnetic resonance spectroscopy (MRS. In order to correct for cerebrospinal fluid content, a spectroscopic voxel needs to be segmented according to different tissue contents. This article aims to detail how automated partial volume segmentation can be undertaken and provides a software framework for researchers to develop their own tools. While many studies have detailed the impact of partial volume correction on proton magnetic resonance spectroscopy quantification, there is a paucity of literature explaining how voxel segmentation can be achieved using freely available neuroimaging packages.

  9. Optimal transformation for correcting partial volume averaging effects in magnetic resonance imaging

    International Nuclear Information System (INIS)

    Soltanian-Zadeh, H.; Windham, J.P.; Yagle, A.E.

    1993-01-01

    Segmentation of a feature of interest while correcting for partial volume averaging effects is a major tool for identification of hidden abnormalities, fast and accurate volume calculation, and three-dimensional visualization in the field of magnetic resonance imaging (MRI). The authors present the optimal transformation for simultaneous segmentation of a desired feature and correction of partial volume averaging effects, while maximizing the signal-to-noise ratio (SNR) of the desired feature. It is proved that correction of partial volume averaging effects requires the removal of the interfering features from the scene. It is also proved that correction of partial volume averaging effects can be achieved merely by a linear transformation. It is finally shown that the optimal transformation matrix is easily obtained using the Gram-Schmidt orthogonalization procedure, which is numerically stable. Applications of the technique to MRI simulation, phantom, and brain images are shown. They show that in all cases the desired feature is segmented from the interfering features and partial volume information is visualized in the resulting transformed images

  10. Apparent CBF decrease with normal aging due to partial volume effects: MR-based partial volume correction on CBF SPECT.

    Science.gov (United States)

    Inoue, Kentaro; Ito, Hiroshi; Goto, Ryoi; Nakagawa, Manabu; Kinomura, Shigeo; Sato, Tachio; Sato, Kazunori; Fukuda, Hiroshi

    2005-06-01

    Several studies using single photon emission tomography (SPECT) have shown changes in cerebral blood flow (CBF) with age, which were associated with partial volume effects by some authors. Some studies have also demonstrated gender-related differences in CBF. The present study aimed to examine age and gender effects on CBF SPECT images obtained using the 99mTc-ethyl cysteinate dimer and a SPECT scanner, before and after partial volume correction (PVC) using magnetic resonance (MR) imaging. Forty-four healthy subjects (29 males and 15 females; age range, 27-64 y; mean age, 50.0 +/- 9.8 y) participated. Each MR image was segmented to yield grey and white matter images and coregistered to a corresponding SPECT image, followed by convolution to approximate the SPECT spatial resolution. PVC-SPECT images were produced using the convoluted grey matter MR (GM-MR) and white matter MR images. The age and gender effects were assessed using SPM99. Decreases with age were detected in the anterolateral prefrontal cortex and in areas along the lateral sulcus and the lateral ventricle, bilaterally, in the GM-MR images and the SPECT images. In the PVC-SPECT images, decreases in CBF in the lateral prefrontal cortex lost their statistical significance. Decreases in CBF with age found along the lateral sulcus and the lateral ventricle, on the other hand, remained statistically significant, but observation of the spatially normalized MR images suggests that these findings are associated with the dilatation of the lateral sulcus and lateral ventricle, which was not completely compensated for by the spatial normalization procedure. Our present study demonstrated that age effects on CBF in healthy subjects could reflect morphological differences with age in grey matter.

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

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    Evans, Eleanor; Buonincontri, Guido [Wolfson Brain Imaging Centre, University of Cambridge, Cambridge (United Kingdom); Izquierdo, David [Athinoula A Martinos Centre, Harvard University, Cambridge, MA (United States); Methner, Carmen [Department of Medicine, University of Cambridge, Cambridge (United Kingdom); Hawkes, Rob C [Wolfson Brain Imaging Centre, University of Cambridge, Cambridge (United Kingdom); Ansorge, Richard E [Department of Physics, University of Cambridge, Cambridge (United Kingdom); Kreig, Thomas [Department of Medicine, University of Cambridge, Cambridge (United Kingdom); Carpenter, T Adrian [Wolfson Brain Imaging Centre, University of Cambridge, Cambridge (United Kingdom); Sawiak, Stephen J [Wolfson Brain Imaging Centre, University of Cambridge, Cambridge (United Kingdom); Behavioural and Clinical Neurosciences Institute, University of Cambridge, Cambridge (United Kingdom)

    2014-07-29

    Kinetic modelling in PET requires the arterial input function (AIF), defined as the time-activity curve (TAC) in plasma. This measure is challenging to obtain in mice due to low blood volumes, resulting in a reliance on image-based methods for AIF derivation. We present a comparison of PET- and MR-based region-of-interest (ROI) analysis to obtain image-derived AIFs from the left ventricle (LV) of a mouse model. ROI-based partial volume correction (PVC) was performed to improve quantification.

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

    International Nuclear Information System (INIS)

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

    2014-01-01

    Kinetic modelling in PET requires the arterial input function (AIF), defined as the time-activity curve (TAC) in plasma. This measure is challenging to obtain in mice due to low blood volumes, resulting in a reliance on image-based methods for AIF derivation. We present a comparison of PET- and MR-based region-of-interest (ROI) analysis to obtain image-derived AIFs from the left ventricle (LV) of a mouse model. ROI-based partial volume correction (PVC) was performed to improve quantification.

  13. A multiresolution image based approach for correction of partial volume effects in emission tomography

    International Nuclear Information System (INIS)

    Boussion, N; Hatt, M; Lamare, F; Bizais, Y; Turzo, A; Rest, C Cheze-Le; Visvikis, D

    2006-01-01

    Partial volume effects (PVEs) are consequences of the limited spatial resolution in emission tomography. They lead to a loss of signal in tissues of size similar to the point spread function and induce activity spillover between regions. Although PVE can be corrected for by using algorithms that provide the correct radioactivity concentration in a series of regions of interest (ROIs), so far little attention has been given to the possibility of creating improved images as a result of PVE correction. Potential advantages of PVE-corrected images include the ability to accurately delineate functional volumes as well as improving tumour-to-background ratio, resulting in an associated improvement in the analysis of response to therapy studies and diagnostic examinations, respectively. The objective of our study was therefore to develop a methodology for PVE correction not only to enable the accurate recuperation of activity concentrations, but also to generate PVE-corrected images. In the multiresolution analysis that we define here, details of a high-resolution image H (MRI or CT) are extracted, transformed and integrated in a low-resolution image L (PET or SPECT). A discrete wavelet transform of both H and L images is performed by using the 'a trous' algorithm, which allows the spatial frequencies (details, edges, textures) to be obtained easily at a level of resolution common to H and L. A model is then inferred to build the lacking details of L from the high-frequency details in H. The process was successfully tested on synthetic and simulated data, proving the ability to obtain accurately corrected images. Quantitative PVE correction was found to be comparable with a method considered as a reference but limited to ROI analyses. Visual improvement and quantitative correction were also obtained in two examples of clinical images, the first using a combined PET/CT scanner with a lymphoma patient and the second using a FDG brain PET and corresponding T1-weighted MRI in

  14. Partial volume effect-corrected FDG PET and grey matter volume loss in patients with mild Alzheimer's disease

    International Nuclear Information System (INIS)

    Samuraki, Miharu; Yanase, Daisuke; Yamada, Masahito; Matsunari, Ichiro; Chen, Wei-Ping; Yajima, Kazuyoshi; Fujikawa, Akihiko; Takeda, Nozomi; Nishimura, Shintaro; Matsuda, Hiroshi

    2007-01-01

    Although 18 F-fluorodeoxyglucose (FDG) PET is an established imaging technique to assess brain glucose utilisation, accurate measurement of tracer concentration is confounded by the presence of partial volume effect (PVE) due to the limited spatial resolution of PET, which is particularly true in atrophic brains such as those encountered in patients with Alzheimer's disease (AD). Our aim was to investigate the effects of PVE correction on FDG PET in conjunction with voxel-based morphometry (VBM) in patients with mild AD. Thirty-nine AD patients and 73 controls underwent FDG PET and MRI. The PVE-corrected grey matter PET images were obtained using an MRI-based three-compartment method. Additionally, the results of PET were compared with grey matter loss detected by VBM. Before PVE correction, reduced FDG uptake was observed in posterior cingulate gyri (PCG) and parieto-temporal lobes (PTL) in AD patients, which persisted after PVE correction. Notably, PVE correction revealed relatively preserved FDG uptake in hippocampal areas, despite the grey matter loss in medial temporal lobe (MTL) revealed by VBM. FDG uptake in PCG and PTL is reduced in AD regardless of whether or not PVE correction is applied, supporting the notion that the reduced FDG uptake in these areas is not the result of atrophy. Furthermore, FDG uptake by grey matter tissue in the MTL, including hippocampal areas, is relatively preserved, suggesting that compensatory mechanisms may play a role in patients with mild AD. (orig.)

  15. Partial volume effect correction in nuclear medicine: assessment with a mathematical phantom

    International Nuclear Information System (INIS)

    Silva, Murilo Collete da; Pozzo, Lorena

    2009-01-01

    Objective: assessment of Van Cittert partial volume effect correction method in nuclear medicine images, with a mathematical phantom. Material and method: we simulated an image of four circular sources of different diameters and intensity of 255 per pixel. The iterative algorithm was applied with 20 iterations and α = 1. We obtained the maximum and average counts on the entire image and in regions of interest placed on each of the sources. We also extracted count profiles plotted along the diameter of each of the sources. Results: the local convergence depends on the size of the source studied: the smaller the source, the greater the number of iterations required. It also depends on the information extracted: the use of average counts provides more homogeneous results than the maximum count. There is a significant improvement in image contrast. Conclusion: this study showed the possibility of qualitative and quantitative improvement in applying the bidimensional iterative Van Cittert method to images of simple geometry. (author)

  16. A simple algorithm for subregional striatal uptake analysis with partial volume correction in dopaminergic PET imaging

    International Nuclear Information System (INIS)

    Lue Kunhan; Lin Hsinhon; Chuang Kehshih; Kao Chihhao, K.; Hsieh Hungjen; Liu Shuhsin

    2014-01-01

    In positron emission tomography (PET) of the dopaminergic system, quantitative measurements of nigrostriatal dopamine function are useful for differential diagnosis. A subregional analysis of striatal uptake enables the diagnostic performance to be more powerful. However, the partial volume effect (PVE) induces an underestimation of the true radioactivity concentration in small structures. This work proposes a simple algorithm for subregional analysis of striatal uptake with partial volume correction (PVC) in dopaminergic PET imaging. The PVC algorithm analyzes the separate striatal subregions and takes into account the PVE based on the recovery coefficient (RC). The RC is defined as the ratio of the PVE-uncorrected to PVE-corrected radioactivity concentration, and is derived from a combination of the traditional volume of interest (VOI) analysis and the large VOI technique. The clinical studies, comprising 11 patients with Parkinson's disease (PD) and 6 healthy subjects, were used to assess the impact of PVC on the quantitative measurements. Simulations on a numerical phantom that mimicked realistic healthy and neurodegenerative situations were used to evaluate the performance of the proposed PVC algorithm. In both the clinical and the simulation studies, the striatal-to-occipital ratio (SOR) values for the entire striatum and its subregions were calculated with and without PVC. In the clinical studies, the SOR values in each structure (caudate, anterior putamen, posterior putamen, putamen, and striatum) were significantly higher by using PVC in contrast to those without. Among the PD patients, the SOR values in each structure and quantitative disease severity ratings were shown to be significantly related only when PVC was used. For the simulation studies, the average absolute percentage error of the SOR estimates before and after PVC were 22.74% and 1.54% in the healthy situation, respectively; those in the neurodegenerative situation were 20.69% and 2

  17. PETPVC: a toolbox for performing partial volume correction techniques in positron emission tomography

    Science.gov (United States)

    Thomas, Benjamin A.; Cuplov, Vesna; Bousse, Alexandre; Mendes, Adriana; Thielemans, Kris; Hutton, Brian F.; Erlandsson, Kjell

    2016-11-01

    Positron emission tomography (PET) images are degraded by a phenomenon known as the partial volume effect (PVE). Approaches have been developed to reduce PVEs, typically through the utilisation of structural information provided by other imaging modalities such as MRI or CT. These methods, known as partial volume correction (PVC) techniques, reduce PVEs by compensating for the effects of the scanner resolution, thereby improving the quantitative accuracy. The PETPVC toolbox described in this paper comprises a suite of methods, both classic and more recent approaches, for the purposes of applying PVC to PET data. Eight core PVC techniques are available. These core methods can be combined to create a total of 22 different PVC techniques. Simulated brain PET data are used to demonstrate the utility of toolbox in idealised conditions, the effects of applying PVC with mismatched point-spread function (PSF) estimates and the potential of novel hybrid PVC methods to improve the quantification of lesions. All anatomy-based PVC techniques achieve complete recovery of the PET signal in cortical grey matter (GM) when performed in idealised conditions. Applying deconvolution-based approaches results in incomplete recovery due to premature termination of the iterative process. PVC techniques are sensitive to PSF mismatch, causing a bias of up to 16.7% in GM recovery when over-estimating the PSF by 3 mm. The recovery of both GM and a simulated lesion was improved by combining two PVC techniques together. The PETPVC toolbox has been written in C++, supports Windows, Mac and Linux operating systems, is open-source and publicly available.

  18. Partial volume effect estimation and correction in the aortic vascular wall in PET imaging

    International Nuclear Information System (INIS)

    Burg, S; Le Guludec, D; Dupas, A; Stute, S; Dieudonné, A; Huet, P; Buvat, I

    2013-01-01

    We evaluated the impact of partial volume effect (PVE) in the assessment of arterial diseases with 18 FDG PET. An anthropomorphic digital phantom enabling the modeling of aorta related diseases like atherosclerosis and arteritis was used. Based on this phantom, we performed GATE Monte Carlo simulations to produce realistic PET images with a known organ segmentation and ground truth activity values. Images corresponding to 15 different activity-concentration ratios between the aortic wall and the blood and to 7 different wall thicknesses were generated. Using the PET images, we compared the theoretical wall-to-blood activity-concentration ratios (WBRs) with the measured WBRs obtained with five measurement methods: (1) measurement made by a physician (Expert), (2) automated measurement supposed to mimic the physician measurements (Max), (3) simple correction based on a recovery coefficient (Max-RC), (4) measurement based on an ideal VOI segmentation (Mean-VOI) and (5) measurement corrected for PVE using an ideal geometric transfer matrix (GTM) method. We found that Mean-VOI WBRs values were strongly affected by PVE. WBRs obtained by the physician measurement, by the Max method and by the Max-RC method were more accurate than WBRs obtained with the Mean-VOI approach. However Expert, Max and Max-RC WBRs strongly depended on the wall thickness. Only the GTM corrected WBRs did not depend on the wall thickness. Using the GTM method, we obtained more reproducible ratio values that could be compared across wall thickness. Yet, the feasibility of the implementation of a GTM-like method on real data remains to be studied. (paper)

  19. Cerebral blood flow in temporal lobe epilepsy: a partial volume correction study

    International Nuclear Information System (INIS)

    Giovacchini, Giampiero; Bonwetsch, Robert; Theodore, William H.; Herscovitch, Peter; Carson, Richard E.

    2007-01-01

    Previous studies in temporal lobe epilepsy (TLE) have shown that, owing to brain atrophy, positron emission tomography (PET) can overestimate deficits in measures of cerebral function such as glucose metabolism (CMR glu ) and neuroreceptor binding. The magnitude of this effect on cerebral blood flow (CBF) is unexplored. The aim of this study was to assess CBF deficits in TLE before and after magnetic resonance imaging-based partial volume correction (PVC). Absolute values of CBF for 21 TLE patients and nine controls were computed before and after PVC. In TLE patients, quantitative CMR glu measurements also were obtained. Before PVC, regional values of CBF were significantly (p glu in middle and inferior temporal cortex, fusiform gyrus and hippocampus both before and after PVC. A significant positive relationship between disease duration and AIs for CMR glu , but not CBF, was detected in hippocampus and amygdala, before but not after PVC. PVC should be used for PET CBF measurements in patients with TLE. Reduced blood flow, in contrast to glucose metabolism, is mainly due to structural changes. (orig.)

  20. Cerebral blood flow in temporal lobe epilepsy: a partial volume correction study

    Energy Technology Data Exchange (ETDEWEB)

    Giovacchini, Giampiero [University Milano-Bicocca, Milan (Italy); Bonwetsch, Robert; Theodore, William H. [National Institute of Neurological Diseases and Strokes, Clinical Epilepsy Section, Bethesda, MD (United States); Herscovitch, Peter [National Institutes of Health, PET Department, Clinical Center, Bethesda, MD (United States); Carson, Richard E. [Yale PET Center, New Haven, CT (United States)

    2007-12-15

    Previous studies in temporal lobe epilepsy (TLE) have shown that, owing to brain atrophy, positron emission tomography (PET) can overestimate deficits in measures of cerebral function such as glucose metabolism (CMR{sub glu}) and neuroreceptor binding. The magnitude of this effect on cerebral blood flow (CBF) is unexplored. The aim of this study was to assess CBF deficits in TLE before and after magnetic resonance imaging-based partial volume correction (PVC). Absolute values of CBF for 21 TLE patients and nine controls were computed before and after PVC. In TLE patients, quantitative CMR{sub glu} measurements also were obtained. Before PVC, regional values of CBF were significantly (p<0.05) lower in TLE patients than in controls in all regions, except the fusiform gyrus contralateral to the epileptic focus. After PVC, statistical significance was maintained in only four regions: ipsilateral inferior temporal cortex, bilateral insula and contralateral amygdala. There was no significant difference between patients and controls in CBF asymmetry indices (AIs) in any region before or after PVC. In TLE patients, AIs for CBF were significantly smaller than for CMR{sub glu} in middle and inferior temporal cortex, fusiform gyrus and hippocampus both before and after PVC. A significant positive relationship between disease duration and AIs for CMR{sub glu}, but not CBF, was detected in hippocampus and amygdala, before but not after PVC. PVC should be used for PET CBF measurements in patients with TLE. Reduced blood flow, in contrast to glucose metabolism, is mainly due to structural changes. (orig.)

  1. Considerations and code for partial volume correcting [18F]-AV-1451 tau PET data

    Directory of Open Access Journals (Sweden)

    Suzanne L. Baker

    2017-12-01

    Full Text Available [18F]-AV-1451 is a leading tracer used with positron emission tomography (PET to quantify tau pathology. However, [18F]-AV-1451 shows “off target” or non-specific binding, which we define as binding of the tracer in unexpected areas unlikely to harbor aggregated tau based on autopsy literature [1]. Along with caudate, putamen, pallidum and thalamus non-specific binding [2,3], we have found binding in the superior portion of the cerebellar gray matter, leading us to use inferior cerebellar gray as the reference region. We also addressed binding in the posterior portion of the choroid plexus. PET signal unlikely to be associated with tau also occurs in skull, meninges and soft tissue (see e.g. [4]. We refer to [18F]-AV-1451 binding in the skull and meninges as extra-cortical hotspots (ECH and find them near lateral and medial orbitofrontal, lateral occipital, inferior and middle temporal, superior and inferior parietal, and inferior cerebellar gray matter. Lastly, the choroid plexus also shows non-specific binding that bleeds into hippocampus. We are providing the code (http://www.runmycode.org/companion/view/2798 used to create different regions of interest (ROIs that we then used to perform Partial Volume Correction (PVC using the Rousset geometric transfer matrix method (GTM, [5]. This method was used in the companion article, “Comparison of multiple tau-PET measures as biomarkers in aging and Alzheimer's Disease” ([6], DOI 10.1016/j.neuroimage.2017.05.058.

  2. Fast Computation of Solvation Free Energies with Molecular Density Functional Theory: Thermodynamic-Ensemble Partial Molar Volume Corrections.

    Science.gov (United States)

    Sergiievskyi, Volodymyr P; Jeanmairet, Guillaume; Levesque, Maximilien; Borgis, Daniel

    2014-06-05

    Molecular density functional theory (MDFT) offers an efficient implicit-solvent method to estimate molecule solvation free-energies, whereas conserving a fully molecular representation of the solvent. Even within a second-order approximation for the free-energy functional, the so-called homogeneous reference fluid approximation, we show that the hydration free-energies computed for a data set of 500 organic compounds are of similar quality as those obtained from molecular dynamics free-energy perturbation simulations, with a computer cost reduced by 2-3 orders of magnitude. This requires to introduce the proper partial volume correction to transform the results from the grand canonical to the isobaric-isotherm ensemble that is pertinent to experiments. We show that this correction can be extended to 3D-RISM calculations, giving a sound theoretical justification to empirical partial molar volume corrections that have been proposed recently.

  3. Simulation-based partial volume correction for dopaminergic PET imaging. Impact of segmentation accuracy

    Energy Technology Data Exchange (ETDEWEB)

    Rong, Ye; Winz, Oliver H. [University Hospital Aachen (Germany). Dept. of Nuclear Medicine; Vernaleken, Ingo [University Hospital Aachen (Germany). Dept. of Psychiatry, Psychotherapy and Psychosomatics; Goedicke, Andreas [University Hospital Aachen (Germany). Dept. of Nuclear Medicine; High Tech Campus, Philips Research Lab., Eindhoven (Netherlands); Mottaghy, Felix M. [University Hospital Aachen (Germany). Dept. of Nuclear Medicine; Maastricht University Medical Center (Netherlands). Dept. of Nuclear Medicine; Rota Kops, Elena [Forschungszentrum Juelich (Germany). Inst. of Neuroscience and Medicine-4

    2015-07-01

    Partial volume correction (PVC) is an essential step for quantitative positron emission tomography (PET). In the present study, PVELab, a freely available software, is evaluated for PVC in {sup 18}F-FDOPA brain-PET, with a special focus on the accuracy degradation introduced by various MR-based segmentation approaches. Methods Four PVC algorithms (M-PVC; MG-PVC; mMG-PVC; and R-PVC) were analyzed on simulated {sup 18}F-FDOPA brain-PET images. MR image segmentation was carried out using FSL (FMRIB Software Library) and SPM (Statistical Parametric Mapping) packages, including additional adaptation for subcortical regions (SPM{sub L}). Different PVC and segmentation combinations were compared with respect to deviations in regional activity values and time-activity curves (TACs) of the occipital cortex (OCC), caudate nucleus (CN), and putamen (PUT). Additionally, the PVC impact on the determination of the influx constant (K{sub i}) was assessed. Results Main differences between tissue-maps returned by three segmentation algorithms were found in the subcortical region, especially at PUT. Average misclassification errors in combination with volume reduction was found to be lowest for SPM{sub L} (PUT < 30%) and highest for FSL (PUT > 70%). Accurate recovery of activity data at OCC is achieved by M-PVC (apparent recovery coefficient varies between 0.99 and 1.10). The other three evaluated PVC algorithms have demonstrated to be more suitable for subcortical regions with MG-PVC and mMG-PVC being less prone to the largest tissue misclassification error simulated in this study. Except for M-PVC, quantification accuracy of K{sub i} for CN and PUT was clearly improved by PVC. Conclusions The regional activity value of PUT was appreciably overcorrected by most of the PVC approaches employing FSL or SPM segmentation, revealing the importance of accurate MR image segmentation for the presented PVC framework. The selection of a PVC approach should be adapted to the anatomical

  4. Symmetric geometric transfer matrix partial volume correction for PET imaging: principle, validation and robustness

    Science.gov (United States)

    Sattarivand, Mike; Kusano, Maggie; Poon, Ian; Caldwell, Curtis

    2012-11-01

    Limited spatial resolution of positron emission tomography (PET) often requires partial volume correction (PVC) to improve the accuracy of quantitative PET studies. Conventional region-based PVC methods use co-registered high resolution anatomical images (e.g. computed tomography (CT) or magnetic resonance images) to identify regions of interest. Spill-over between regions is accounted for by calculating regional spread functions (RSFs) in a geometric transfer matrix (GTM) framework. This paper describes a new analytically derived symmetric GTM (sGTM) method that relies on spill-over between RSFs rather than between regions. It is shown that the sGTM is mathematically equivalent to Labbe's method; however it is a region-based method rather than a voxel-based method and it avoids handling large matrices. The sGTM method was validated using two three-dimensional (3D) digital phantoms and one physical phantom. A 3D digital sphere phantom with sphere diameters ranging from 5 to 30 mm and a sphere-to-background uptake ratio of 3-to-1 was used. A 3D digital brain phantom was used with four different anatomical regions and a background region with different activities assigned to each region. A physical sphere phantom with the same geometry and uptake as the digital sphere phantom was manufactured and PET-CT images were acquired. Using these three phantoms, the performance of the sGTM method was assessed against that of the GTM method in terms of accuracy, precision, noise propagation and robustness. The robustness was assessed by applying mis-registration errors and errors in estimates of PET point spread function (PSF). In all three phantoms, the results showed that the sGTM method has accuracy similar to that of the GTM method and within 5%. However, the sGTM method showed better precision and noise propagation than the GTM method, especially for spheres smaller than 13 mm. Moreover, the sGTM method was more robust than the GTM method when mis-registration errors or

  5. Symmetric geometric transfer matrix partial volume correction for PET imaging: principle, validation and robustness

    International Nuclear Information System (INIS)

    Sattarivand, Mike; Caldwell, Curtis; Kusano, Maggie; Poon, Ian

    2012-01-01

    Limited spatial resolution of positron emission tomography (PET) often requires partial volume correction (PVC) to improve the accuracy of quantitative PET studies. Conventional region-based PVC methods use co-registered high resolution anatomical images (e.g. computed tomography (CT) or magnetic resonance images) to identify regions of interest. Spill-over between regions is accounted for by calculating regional spread functions (RSFs) in a geometric transfer matrix (GTM) framework. This paper describes a new analytically derived symmetric GTM (sGTM) method that relies on spill-over between RSFs rather than between regions. It is shown that the sGTM is mathematically equivalent to Labbe's method; however it is a region-based method rather than a voxel-based method and it avoids handling large matrices. The sGTM method was validated using two three-dimensional (3D) digital phantoms and one physical phantom. A 3D digital sphere phantom with sphere diameters ranging from 5 to 30 mm and a sphere-to-background uptake ratio of 3-to-1 was used. A 3D digital brain phantom was used with four different anatomical regions and a background region with different activities assigned to each region. A physical sphere phantom with the same geometry and uptake as the digital sphere phantom was manufactured and PET-CT images were acquired. Using these three phantoms, the performance of the sGTM method was assessed against that of the GTM method in terms of accuracy, precision, noise propagation and robustness. The robustness was assessed by applying mis-registration errors and errors in estimates of PET point spread function (PSF). In all three phantoms, the results showed that the sGTM method has accuracy similar to that of the GTM method and within 5%. However, the sGTM method showed better precision and noise propagation than the GTM method, especially for spheres smaller than 13 mm. Moreover, the sGTM method was more robust than the GTM method when mis-registration errors or

  6. Impact of partial-volume correction in oncological PET studies. A systematic review and meta-analysis

    Energy Technology Data Exchange (ETDEWEB)

    Cysouw, Matthijs C.F.; Kramer, Gerbrand M.; Hoekstra, Otto S. [VU University Medical Centre, Department of Radiology and Nuclear Medicine, Amsterdam (Netherlands); Schoonmade, Linda J. [VU University Medical Centre, Department of Medical Library, Amsterdam (Netherlands); Boellaard, Ronald [VU University Medical Centre, Department of Radiology and Nuclear Medicine, Amsterdam (Netherlands); University Medical Centre Groningen, Department of Nuclear Medicine and Molecular Imaging, Groningen (Netherlands); Vet, Henrica C.W. de [VU University Medical Centre, Department of Epidemiology and Biostatistics, Amsterdam (Netherlands)

    2017-11-15

    Positron-emission tomography can be useful in oncology for diagnosis, (re)staging, determining prognosis, and response assessment. However, partial-volume effects hamper accurate quantification of lesions <2-3 x the PET system's spatial resolution, and the clinical impact of this is not evident. This systematic review provides an up-to-date overview of studies investigating the impact of partial-volume correction (PVC) in oncological PET studies. We searched in PubMed and Embase databases according to the PRISMA statement, including studies from inception till May 9, 2016. Two reviewers independently screened all abstracts and eligible full-text articles and performed quality assessment according to QUADAS-2 and QUIPS criteria. For a set of similar diagnostic studies, we statistically pooled the results using bivariate meta-regression. Thirty-one studies were eligible for inclusion. Overall, study quality was good. For diagnosis and nodal staging, PVC yielded a strong trend of increased sensitivity at expense of specificity. Meta-analysis of six studies investigating diagnosis of pulmonary nodules (679 lesions) showed no significant change in diagnostic accuracy after PVC (p = 0.222). Prognostication was not improved for non-small cell lung cancer and esophageal cancer, whereas it did improve for head and neck cancer. Response assessment was not improved by PVC for (locally advanced) breast cancer or rectal cancer, and it worsened in metastatic colorectal cancer. The accumulated evidence to date does not support routine application of PVC in standard clinical PET practice. Consensus on the preferred PVC methodology in oncological PET should be reached. Partial-volume-corrected data should be used as adjuncts to, but not yet replacement for, uncorrected data. (orig.)

  7. Different partial volume correction methods lead to different conclusions: An (18)F-FDG-PET study of aging.

    Science.gov (United States)

    Greve, Douglas N; Salat, David H; Bowen, Spencer L; Izquierdo-Garcia, David; Schultz, Aaron P; Catana, Ciprian; Becker, J Alex; Svarer, Claus; Knudsen, Gitte M; Sperling, Reisa A; Johnson, Keith A

    2016-05-15

    A cross-sectional group study of the effects of aging on brain metabolism as measured with (18)F-FDG-PET was performed using several different partial volume correction (PVC) methods: no correction (NoPVC), Meltzer (MZ), Müller-Gärtner (MG), and the symmetric geometric transfer matrix (SGTM) using 99 subjects aged 65-87years from the Harvard Aging Brain study. Sensitivity to parameter selection was tested for MZ and MG. The various methods and parameter settings resulted in an extremely wide range of conclusions as to the effects of age on metabolism, from almost no changes to virtually all of cortical regions showing a decrease with age. Simulations showed that NoPVC had significant bias that made the age effect on metabolism appear to be much larger and more significant than it is. MZ was found to be the same as NoPVC for liberal brain masks; for conservative brain masks, MZ showed few areas correlated with age. MG and SGTM were found to be similar; however, MG was sensitive to a thresholding parameter that can result in data loss. CSF uptake was surprisingly high at about 15% of that in gray matter. The exclusion of CSF from SGTM and MG models, which is almost universally done, caused a substantial loss in the power to detect age-related changes. This diversity of results reflects the literature on the metabolism of aging and suggests that extreme care should be taken when applying PVC or interpreting results that have been corrected for partial volume effects. Using the SGTM, significant age-related changes of about 7% per decade were found in frontal and cingulate cortices as well as primary visual and insular cortices. Copyright © 2016 Elsevier Inc. All rights reserved.

  8. Different Partial Volume Correction Methods Lead to Different Conclusions: an 18F-FDG PET Study of Aging

    Science.gov (United States)

    Greve, Douglas N.; Salat, David H.; Bowen, Spencer L.; Izquierdo-Garcia, David; Schultz, Aaron P.; Catana, Ciprian; Becker, J. Alex; Svarer, Claus; Knudsen, Gitte; Sperling, Reisa A.; Johnson, Keith A.

    2016-01-01

    A cross-sectional group study of the effects of aging on brain metabolism as measured with 18F-FDG PET was performed using several different partial volume correction (PVC) methods: no correction (NoPVC), Meltzer (MZ), Müller-Gärtner (MG), and the symmetric geometric transfer matrix (SGTM) using 99 subjects aged 65-87 from the Harvard Aging Brain study. Sensitivity to parameter selection was tested for MZ and MG. The various methods and parameter settings resulted in an extremely wide range of conclusions as to the effects of age on metabolism, from almost no changes to virtually all of cortical regions showing a decrease with age. Simulations showed that NoPVC had significant bias that made the age effect on metabolism appear to be much larger and more significant than it is. MZ was found to be the same as NoPVC for liberal brain masks; for conservative brain masks, MZ showed few areas correlated with age. MG and SGTM were found to be similar; however, MG was sensitive to a thresholding parameter that can result in data loss. CSF uptake was surprisingly high at about 15% of that in gray matter. Exclusion of CSF from SGTM and MG models, which is almost universally done, caused a substantial loss in the power to detect age-related changes. This diversity of results reflects the literature on the metabolism of aging and suggests that extreme care should be taken when applying PVC or interpreting results that have been corrected for partial volume effects. Using the SGTM, significant age-related changes of about 7% per decade were found in frontal and cingulate cortices as well as primary visual and insular cortices. PMID:26915497

  9. Wavelet-based partial volume effect correction for simultaneous MR/PET of the carotid arteries

    Energy Technology Data Exchange (ETDEWEB)

    Bini, Jason; Eldib, Mootaz [Translational and Molecular Imaging Institute, Icahn School of Medicine at Mount Sinai, NY, NY (United States); Department of Biomedical Engineering, The City College of New York, NY, NY (United States); Robson, Philip M; Fayad, Zahi A [Translational and Molecular Imaging Institute, Icahn School of Medicine at Mount Sinai, NY, NY (United States)

    2014-07-29

    Simultaneous MR/PET scanners allow for the exploration and development of novel PVE correction techniques without the challenges of coregistration of MR and PET. The development of a wavelet-based PVE correction method, to improve PET quantification, has proven successful in brain PET.{sup 2} We report here the first attempt to apply these methods to simultaneous MR/PET imaging of the carotid arteries.

  10. Wavelet-based partial volume effect correction for simultaneous MR/PET of the carotid arteries

    International Nuclear Information System (INIS)

    Bini, Jason; Eldib, Mootaz; Robson, Philip M; Fayad, Zahi A

    2014-01-01

    Simultaneous MR/PET scanners allow for the exploration and development of novel PVE correction techniques without the challenges of coregistration of MR and PET. The development of a wavelet-based PVE correction method, to improve PET quantification, has proven successful in brain PET. 2 We report here the first attempt to apply these methods to simultaneous MR/PET imaging of the carotid arteries.

  11. Quantitation of regional cerebral blood flow corrected for partial volume effect using O-15 water and PET

    DEFF Research Database (Denmark)

    IIda, H.; Law, I.; Pakkenberg, B.

    2000-01-01

    Limited spatial resolution of positron emission tomography (PET) can cause significant underestimation in the observed regional radioactivity concentration (so-called partial volume effect or PVE) resulting in systematic errors in estimating quantitative physiologic parameters. The authors have...... formulated four mathematical models that describe the dynamic behavior of a freely diffusible tracer (H215O) in a region of interest (ROI) incorporating estimates of regional tissue flow that are independent of PVE. The current study was intended to evaluate the feasibility of these models and to establish...... a methodology to accurately quantify regional cerebral blood flow (CBF) corrected for PVE in cortical gray matter regions. Five monkeys were studied with PET after IV H2(15)O two times (n = 3) or three times (n = 2) in a row. Two ROIs were drawn on structural magnetic resonance imaging (MRI) scans and projected...

  12. Markov random field and Gaussian mixture for segmented MRI-based partial volume correction in PET

    International Nuclear Information System (INIS)

    Bousse, Alexandre; Thomas, Benjamin A; Erlandsson, Kjell; Hutton, Brian F; Pedemonte, Stefano; Ourselin, Sébastien; Arridge, Simon

    2012-01-01

    In this paper we propose a segmented magnetic resonance imaging (MRI) prior-based maximum penalized likelihood deconvolution technique for positron emission tomography (PET) images. The model assumes the existence of activity classes that behave like a hidden Markov random field (MRF) driven by the segmented MRI. We utilize a mean field approximation to compute the likelihood of the MRF. We tested our method on both simulated and clinical data (brain PET) and compared our results with PET images corrected with the re-blurred Van Cittert (VC) algorithm, the simplified Guven (SG) algorithm and the region-based voxel-wise (RBV) technique. We demonstrated our algorithm outperforms the VC algorithm and outperforms SG and RBV corrections when the segmented MRI is inconsistent (e.g. mis-segmentation, lesions, etc) with the PET image. (paper)

  13. Partial volume effect correction in PET using regularized iterative deconvolution with variance control based on local topology

    International Nuclear Information System (INIS)

    Kirov, A S; Schmidtlein, C R; Piao, J Z

    2008-01-01

    Correcting positron emission tomography (PET) images for the partial volume effect (PVE) due to the limited resolution of PET has been a long-standing challenge. Various approaches including incorporation of the system response function in the reconstruction have been previously tested. We present a post-reconstruction PVE correction based on iterative deconvolution using a 3D maximum likelihood expectation-maximization (MLEM) algorithm. To achieve convergence we used a one step late (OSL) regularization procedure based on the assumption of local monotonic behavior of the PET signal following Alenius et al. This technique was further modified to selectively control variance depending on the local topology of the PET image. No prior 'anatomic' information is needed in this approach. An estimate of the noise properties of the image is used instead. The procedure was tested for symmetric and isotropic deconvolution functions with Gaussian shape and full width at half-maximum (FWHM) ranging from 6.31 mm to infinity. The method was applied to simulated and experimental scans of the NEMA NU 2 image quality phantom with the GE Discovery LS PET/CT scanner. The phantom contained uniform activity spheres with diameters ranging from 1 cm to 3.7 cm within uniform background. The optimal sphere activity to variance ratio was obtained when the deconvolution function was replaced by a step function few voxels wide. In this case, the deconvolution method converged in ∼3-5 iterations for most points on both the simulated and experimental images. For the 1 cm diameter sphere, the contrast recovery improved from 12% to 36% in the simulated and from 21% to 55% in the experimental data. Recovery coefficients between 80% and 120% were obtained for all larger spheres, except for the 13 mm diameter sphere in the simulated scan (68%). No increase in variance was observed except for a few voxels neighboring strong activity gradients and inside the largest spheres. Testing the method for

  14. Octanol-Water Partition Coefficient from 3D-RISM-KH Molecular Theory of Solvation with Partial Molar Volume Correction.

    Science.gov (United States)

    Huang, WenJuan; Blinov, Nikolay; Kovalenko, Andriy

    2015-04-30

    The octanol-water partition coefficient is an important physical-chemical characteristic widely used to describe hydrophobic/hydrophilic properties of chemical compounds. The partition coefficient is related to the transfer free energy of a compound from water to octanol. Here, we introduce a new protocol for prediction of the partition coefficient based on the statistical-mechanical, 3D-RISM-KH molecular theory of solvation. It was shown recently that with the compound-solvent correlation functions obtained from the 3D-RISM-KH molecular theory of solvation, the free energy functional supplemented with the correction linearly related to the partial molar volume obtained from the Kirkwood-Buff/3D-RISM theory, also called the "universal correction" (UC), provides accurate prediction of the hydration free energy of small compounds, compared to explicit solvent molecular dynamics [ Palmer , D. S. ; J. Phys.: Condens. Matter 2010 , 22 , 492101 ]. Here we report that with the UC reparametrized accordingly this theory also provides an excellent agreement with the experimental data for the solvation free energy in nonpolar solvent (1-octanol) and so accurately predicts the octanol-water partition coefficient. The performance of the Kovalenko-Hirata (KH) and Gaussian fluctuation (GF) functionals of the solvation free energy, with and without UC, is tested on a large library of small compounds with diverse functional groups. The best agreement with the experimental data for octanol-water partition coefficients is obtained with the KH-UC solvation free energy functional.

  15. Effects of partial volume correction on discrimination between very early Alzheimer's dementia and controls using brain perfusion SPECT

    International Nuclear Information System (INIS)

    Kanetaka, Hidekazu; Matsuda, Hiroshi; Ohnishi, Takashi; Imabayashi, Etsuko; Tanaka, Fumiko; Asada, Takashi; Yamashita, Fumio; Nakano, Seigo; Takasaki, Masaru

    2004-01-01

    We assessed the accuracy of brain perfusion single-photon emission computed tomography (SPECT) in discriminating between patients with probable Alzheimer's disease (AD) at the very early stage and age-matched controls before and after partial volume correction (PVC). Three-dimensional MRI was used for PVC. We randomly divided the subjects into two groups. The first group, comprising 30 patients and 30 healthy volunteers, was used to identify the brain area with the most significant decrease in regional cerebral blood flow (rCBF) in patients compared with normal controls based on the voxel-based analysis of a group comparison. The second group, comprising 31 patients and 31 healthy volunteers, was used to study the improvement in diagnostic accuracy provided by PVC. A Z score map for a SPECT image of a subject was obtained by comparison with mean and standard deviation SPECT images of the healthy volunteers for each voxel after anatomical standardization and voxel normalization to global mean or cerebellar values using the following equation: Z score = ([control mean]-[individual value])/(control SD). Analysis of receiver operating characteristics curves for a Z score discriminating AD and controls in the posterior cingulate gyrus, where a significant decrease in rCBF was identified in the first group, showed that the PVC significantly enhanced the accuracy of the SPECT diagnosis of very early AD from 73.9% to 83.7% with global mean normalization. The PVC mildly enhanced the accuracy from 73.1% to 76.3% with cerebellar normalization. This result suggests that early diagnosis of AD requires PVC in a SPECT study. (orig.)

  16. Effect of partial volume correction on muscarinic cholinergic receptor imaging with single-photon emission tomography in patients with temporal lobe epilepsy

    International Nuclear Information System (INIS)

    Weckesser, M.; Ziemons, K.; Griessmeier, M.; Sonnenberg, F.; Langen, K.J.; Mueller-Gaertner, H.W.; Hufnagel, A.; Elger, C.E.; Hacklaender, T.; Holschbach, M.

    1997-01-01

    Animal experiments and preliminary results in humans have indicated alterations of hippocampal muscarinic acetylcholine receptors (mAChR) in temporal lobe epilepsy. Patients with temporal lobe epilepsy often present with a reduction in hippocampal volume. The aim of this study was to investigate the influence of hippocampal atrophy on the quantification of mAChR with single photon emission tomography (SPET) in patients with temporal lobe epilepsy. Cerebral uptake of the muscarinic cholinergic antagonist [ 123 I]4-iododexetimide (IDex) was investigated by SPET in patients suffering from temporal lobe epilepsy of unilateral (n=6) or predominantly unilateral (n=1) onset. Regions of interest were drawn on co-registered magnetic resonance images. Hippocampal volume was determined in these regions and was used to correct the SPET results for partial volume effects. A ratio of hippocampal IDex binding on the affected side to that on the unaffected side was used to detect changes in muscarinic cholinergic receptor density. Before partial volume correction a decrease in hippocampal IDex binding on the focus side was found in each patient. After partial volume no convincing differences remained. Our results indicate that the reduction in hippocampal IDex binding in patients with epilepsy is due to a decrease in hippocampal volume rather than to a decrease in receptor concentration. (orig.). With 2 figs., 2 tabs

  17. A method for partial volume correction of PET-imaged tumor heterogeneity using expectation maximization with a spatially varying point spread function

    International Nuclear Information System (INIS)

    Barbee, David L; Holden, James E; Nickles, Robert J; Jeraj, Robert; Flynn, Ryan T

    2010-01-01

    Tumor heterogeneities observed in positron emission tomography (PET) imaging are frequently compromised by partial volume effects which may affect treatment prognosis, assessment or future implementations such as biologically optimized treatment planning (dose painting). This paper presents a method for partial volume correction of PET-imaged heterogeneous tumors. A point source was scanned on a GE Discovery LS at positions of increasing radii from the scanner's center to obtain the spatially varying point spread function (PSF). PSF images were fit in three dimensions to Gaussian distributions using least squares optimization. Continuous expressions were devised for each Gaussian width as a function of radial distance, allowing for generation of the system PSF at any position in space. A spatially varying partial volume correction (SV-PVC) technique was developed using expectation maximization (EM) and a stopping criterion based on the method's correction matrix generated for each iteration. The SV-PVC was validated using a standard tumor phantom and a tumor heterogeneity phantom and was applied to a heterogeneous patient tumor. SV-PVC results were compared to results obtained from spatially invariant partial volume correction (SINV-PVC), which used directionally uniform three-dimensional kernels. SV-PVC of the standard tumor phantom increased the maximum observed sphere activity by 55 and 40% for 10 and 13 mm diameter spheres, respectively. Tumor heterogeneity phantom results demonstrated that as net changes in the EM correction matrix decreased below 35%, further iterations improved overall quantitative accuracy by less than 1%. SV-PVC of clinically observed tumors frequently exhibited changes of ±30% in regions of heterogeneity. The SV-PVC method implemented spatially varying kernel widths and automatically determined the number of iterations for optimal restoration, parameters which are arbitrarily chosen in SINV-PVC. Comparing SV-PVC to SINV-PVC demonstrated

  18. Brain extraction in partial volumes T2*@7T by using a quasi-anatomic segmentation with bias field correction.

    Science.gov (United States)

    Valente, João; Vieira, Pedro M; Couto, Carlos; Lima, Carlos S

    2018-02-01

    Poor brain extraction in Magnetic Resonance Imaging (MRI) has negative consequences in several types of brain post-extraction such as tissue segmentation and related statistical measures or pattern recognition algorithms. Current state of the art algorithms for brain extraction work on weighted T1 and T2, being not adequate for non-whole brain images such as the case of T2*FLASH@7T partial volumes. This paper proposes two new methods that work directly in T2*FLASH@7T partial volumes. The first is an improvement of the semi-automatic threshold-with-morphology approach adapted to incomplete volumes. The second method uses an improved version of a current implementation of the fuzzy c-means algorithm with bias correction for brain segmentation. Under high inhomogeneity conditions the performance of the first method degrades, requiring user intervention which is unacceptable. The second method performed well for all volumes, being entirely automatic. State of the art algorithms for brain extraction are mainly semi-automatic, requiring a correct initialization by the user and knowledge of the software. These methods can't deal with partial volumes and/or need information from atlas which is not available in T2*FLASH@7T. Also, combined volumes suffer from manipulations such as re-sampling which deteriorates significantly voxel intensity structures making segmentation tasks difficult. The proposed method can overcome all these difficulties, reaching good results for brain extraction using only T2*FLASH@7T volumes. The development of this work will lead to an improvement of automatic brain lesions segmentation in T2*FLASH@7T volumes, becoming more important when lesions such as cortical Multiple-Sclerosis need to be detected. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Optimized statistical parametric mapping for partial-volume-corrected amyloid positron emission tomography in patients with Alzheimer's disease and Lewy body dementia

    Science.gov (United States)

    Oh, Jungsu S.; Kim, Jae Seung; Chae, Sun Young; Oh, Minyoung; Oh, Seung Jun; Cha, Seung Nam; Chang, Ho-Jong; Lee, Chong Sik; Lee, Jae Hong

    2017-03-01

    We present an optimized voxelwise statistical parametric mapping (SPM) of partial-volume (PV)-corrected positron emission tomography (PET) of 11C Pittsburgh Compound B (PiB), incorporating the anatomical precision of magnetic resonance image (MRI) and amyloid β (A β) burden-specificity of PiB PET. First, we applied region-based partial-volume correction (PVC), termed the geometric transfer matrix (GTM) method, to PiB PET, creating MRI-based lobar parcels filled with mean PiB uptakes. Then, we conducted a voxelwise PVC by multiplying the original PET by the ratio of a GTM-based PV-corrected PET to a 6-mm-smoothed PV-corrected PET. Finally, we conducted spatial normalizations of the PV-corrected PETs onto the study-specific template. As such, we increased the accuracy of the SPM normalization and the tissue specificity of SPM results. Moreover, lobar smoothing (instead of whole-brain smoothing) was applied to increase the signal-to-noise ratio in the image without degrading the tissue specificity. Thereby, we could optimize a voxelwise group comparison between subjects with high and normal A β burdens (from 10 patients with Alzheimer's disease, 30 patients with Lewy body dementia, and 9 normal controls). Our SPM framework outperformed than the conventional one in terms of the accuracy of the spatial normalization (85% of maximum likelihood tissue classification volume) and the tissue specificity (larger gray matter, and smaller cerebrospinal fluid volume fraction from the SPM results). Our SPM framework optimized the SPM of a PV-corrected A β PET in terms of anatomical precision, normalization accuracy, and tissue specificity, resulting in better detection and localization of A β burdens in patients with Alzheimer's disease and Lewy body dementia.

  20. Twisted finite-volume corrections to K{sub l3} decays with partially-quenched and rooted-staggered quarks

    Energy Technology Data Exchange (ETDEWEB)

    Bernard, Claude [Department of Physics, Washington University,One Brookings Drive, Saint Louis (United States); Bijnens, Johan [Department of Astronomy and Theoretical Physics, Lund University,Sölvegatan 14A, SE 223-62 Lund (Sweden); Gámiz, Elvira [CAFPE and Departamento de Física Teórica y del Cosmos, Universidad de Granada,Campus de Fuente Nueva, E-18002 Granada (Spain); Relefors, Johan [Department of Astronomy and Theoretical Physics, Lund University,Sölvegatan 14A, SE 223-62 Lund (Sweden)

    2017-03-23

    The determination of |V{sub us}| from kaon semileptonic decays requires the value of the form factor f{sub +}(q{sup 2}=0) which can be calculated precisely on the lattice. We provide the one-loop partially quenched chiral perturbation theory expressions both with and without including the effects of staggered quarks for all form factors at finite volume and with partially twisted boundary conditions for both the vector current and scalar density matrix elements at all q{sup 2}. We point out that at finite volume there are more form factors than just f{sub +} and f{sub −} for the vector current matrix element but that the Ward identity is fully satisfied. The size of the finite-volume corrections at present lattice sizes is small. This will help improve the lattice determination of f{sub +}(q{sup 2}=0) since the finite-volume error is the dominant error source for some calculations. The size of the finite-volume corrections may be estimated on a single lattice ensemble by comparing results for various twist choices.

  1. Generalized Partial Volume

    DEFF Research Database (Denmark)

    Darkner, Sune; Sporring, Jon

    2011-01-01

    Mutual Information (MI) and normalized mutual information (NMI) are popular choices as similarity measure for multimodal image registration. Presently, one of two approaches is often used for estimating these measures: The Parzen Window (PW) and the Generalized Partial Volume (GPV). Their theoret...... of view as well as w.r.t. computational complexity. Finally, we present algorithms for both approaches for NMI which is comparable in speed to Sum of Squared Differences (SSD), and we illustrate the differences between PW and GPV on a number of registration examples....

  2. A comparison of five partial volume correction methods for Tau and Amyloid PET imaging with [18F]THK5351 and [11C]PIB.

    Science.gov (United States)

    Shidahara, Miho; Thomas, Benjamin A; Okamura, Nobuyuki; Ibaraki, Masanobu; Matsubara, Keisuke; Oyama, Senri; Ishikawa, Yoichi; Watanuki, Shoichi; Iwata, Ren; Furumoto, Shozo; Tashiro, Manabu; Yanai, Kazuhiko; Gonda, Kohsuke; Watabe, Hiroshi

    2017-08-01

    To suppress partial volume effect (PVE) in brain PET, there have been many algorithms proposed. However, each methodology has different property due to its assumption and algorithms. Our aim of this study was to investigate the difference among partial volume correction (PVC) method for tau and amyloid PET study. We investigated two of the most commonly used PVC methods, Müller-Gärtner (MG) and geometric transfer matrix (GTM) and also other three methods for clinical tau and amyloid PET imaging. One healthy control (HC) and one Alzheimer's disease (AD) PET studies of both [ 18 F]THK5351 and [ 11 C]PIB were performed using a Eminence STARGATE scanner (Shimadzu Inc., Kyoto, Japan). All PET images were corrected for PVE by MG, GTM, Labbé (LABBE), Regional voxel-based (RBV), and Iterative Yang (IY) methods, with segmented or parcellated anatomical information processed by FreeSurfer, derived from individual MR images. PVC results of 5 algorithms were compared with the uncorrected data. In regions of high uptake of [ 18 F]THK5351 and [ 11 C]PIB, different PVCs demonstrated different SUVRs. The degree of difference between PVE uncorrected and corrected depends on not only PVC algorithm but also type of tracer and subject condition. Presented PVC methods are straight-forward to implement but the corrected images require careful interpretation as different methods result in different levels of recovery.

  3. Towards a universal method for calculating hydration free energies: a 3D reference interaction site model with partial molar volume correction.

    Science.gov (United States)

    Palmer, David S; Frolov, Andrey I; Ratkova, Ekaterina L; Fedorov, Maxim V

    2010-12-15

    We report a simple universal method to systematically improve the accuracy of hydration free energies calculated using an integral equation theory of molecular liquids, the 3D reference interaction site model. A strong linear correlation is observed between the difference of the experimental and (uncorrected) calculated hydration free energies and the calculated partial molar volume for a data set of 185 neutral organic molecules from different chemical classes. By using the partial molar volume as a linear empirical correction to the calculated hydration free energy, we obtain predictions of hydration free energies in excellent agreement with experiment (R = 0.94, σ = 0.99 kcal mol (- 1) for a test set of 120 organic molecules).

  4. Towards a universal method for calculating hydration free energies: a 3D reference interaction site model with partial molar volume correction

    International Nuclear Information System (INIS)

    Palmer, David S; Frolov, Andrey I; Ratkova, Ekaterina L; Fedorov, Maxim V

    2010-01-01

    We report a simple universal method to systematically improve the accuracy of hydration free energies calculated using an integral equation theory of molecular liquids, the 3D reference interaction site model. A strong linear correlation is observed between the difference of the experimental and (uncorrected) calculated hydration free energies and the calculated partial molar volume for a data set of 185 neutral organic molecules from different chemical classes. By using the partial molar volume as a linear empirical correction to the calculated hydration free energy, we obtain predictions of hydration free energies in excellent agreement with experiment (R = 0.94, σ = 0.99 kcal mol -1 for a test set of 120 organic molecules). (fast track communication)

  5. Quantifying [{sup 18}F]fluorodeoxyglucose uptake in the arterial wall: the effects of dual time-point imaging and partial volume effect correction

    Energy Technology Data Exchange (ETDEWEB)

    Blomberg, Bjoern A. [University Medical Center Utrecht, Department of Radiology, Utrecht (Netherlands); Odense University Hospital, Department of Nuclear Medicine, Odense (Denmark); Bashyam, Arjun; Ramachandran, Abhinay; Gholami, Saeid; Houshmand, Sina; Salavati, Ali; Werner, Tom; Alavi, Abass [Hospital of the University of Pennsylvania, Department of Radiology, Philadelphia, PA (United States); Zaidi, Habib [Geneva University Hospital, Division of Nuclear Medicine and Molecular Imaging, Geneva (Switzerland); University of Groningen, Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, Groningen (Netherlands)

    2015-08-15

    The human arterial wall is smaller than the spatial resolution of current positron emission tomographs. Therefore, partial volume effects should be considered when quantifying arterial wall {sup 18}F-FDG uptake. We evaluated the impact of a novel method for partial volume effect (PVE) correction with contrast-enhanced CT (CECT) assistance on quantification of arterial wall {sup 18}F-FDG uptake at different imaging time-points. Ten subjects were assessed by CECT imaging and dual time-point PET/CT imaging at approximately 60 and 180 min after {sup 18}F-FDG administration. For both time-points, uptake of {sup 18}F-FDG was determined in the aortic wall by calculating the blood pool-corrected maximum standardized uptake value (cSUV{sub MAX}) and cSUV{sub MEAN}. The PVE-corrected SUV{sub MEAN} (pvcSUV{sub MEAN}) was also calculated using {sup 18}F-FDG PET/CT and CECT images. Finally, corresponding target-to-background ratios (TBR) were calculated. At 60 min, pvcSUV{sub MEAN} was on average 3.1 times greater than cSUV{sub MAX} (P <.0001) and 8.5 times greater than cSUV{sub MEAN} (P <.0001). At 180 min, pvcSUV{sub MEAN} was on average 2.6 times greater than cSUV{sub MAX} (P <.0001) and 6.6 times greater than cSUV{sub MEAN} (P <.0001). This study demonstrated that CECT-assisted PVE correction significantly influences quantification of arterial wall {sup 18}F-FDG uptake. Therefore, partial volume effects should be considered when quantifying arterial wall {sup 18}F-FDG uptake with PET. (orig.)

  6. Quantification accuracy and partial volume effect in dependence of the attenuation correction of a state-of-the-art small animal PET scanner

    International Nuclear Information System (INIS)

    Mannheim, Julia G; Judenhofer, Martin S; Schmid, Andreas; Pichler, Bernd J; Tillmanns, Julia; Stiller, Detlef; Sossi, Vesna

    2012-01-01

    Quantification accuracy and partial volume effect (PVE) of the Siemens Inveon PET scanner were evaluated. The influence of transmission source activities (40 and 160 MBq) on the quantification accuracy and the PVE were determined. Dynamic range, object size and PVE for different sphere sizes, contrast ratios and positions in the field of view (FOV) were evaluated. The acquired data were reconstructed using different algorithms and correction methods. The activity level of the transmission source and the total emission activity in the FOV strongly influenced the attenuation maps. Reconstruction algorithms, correction methods, object size and location within the FOV had a strong influence on the PVE in all configurations. All evaluated parameters potentially influence the quantification accuracy. Hence, all protocols should be kept constant during a study to allow a comparison between different scans. (paper)

  7. Healthy brain ageing assessed with 18F-FDG PET and age-dependent recovery factors after partial volume effect correction

    Energy Technology Data Exchange (ETDEWEB)

    Bonte, Stijn [IBiTech, Ghent, (Belgium); Ghent University, iMinds - Medical Image and Signal Processing (MEDISIP), Department of Electronics and Information Systems, Ghent (Belgium); University Hospital, Department of Radiology and Nuclear Medicine, Ghent (Belgium); Vandemaele, Pieter; Deblaere, Karel; Goethals, Ingeborg [University Hospital, Department of Radiology and Nuclear Medicine, Ghent (Belgium); Verleden, Stijn; Audenaert, Kurt [University Hospital, Department of Psychiatry, Ghent (Belgium); Holen, Roel van [Ghent University, iMinds - Medical Image and Signal Processing (MEDISIP), Department of Electronics and Information Systems, Ghent (Belgium)

    2017-05-15

    The mechanisms of ageing of the healthy brain are not entirely clarified to date. In recent years several authors have tried to elucidate this topic by using {sup 18}F-FDG positron emission tomography. However, when correcting for partial volume effects (PVE), divergent results were reported. Therefore, it is necessary to evaluate these methods in the presence of atrophy due to ageing. In this paper we first evaluate the performance of two PVE correction techniques with a phantom study: the Rousset method and iterative deconvolution. We show that the ability of the latter method to recover the true activity in a small region decreases with increasing age due to brain atrophy. Next, we have calculated age-dependent recovery factors to correct for this incomplete recovery. These factors were applied to PVE-corrected {sup 18}F-FDG PET scans of healthy subjects for mapping the agedependent metabolism in the brain. Many regions in the brain show a reduced metabolism with ageing, especially in grey matter in the frontal and temporal lobe. An increased metabolism is found in grey matter of the cerebellum and thalamus. Our study resulted in age-dependent recovery factors which can be applied following standard PVE correction methods. Cancelling the effect of atrophy, we found regional changes in {sup 18}F-FDG metabolism with ageing. A decreasing trend is found in the frontal and temporal lobe, whereas an increasing metabolism with ageing is observed in the thalamus and cerebellum.

  8. Establishment of an open database of realistic simulated data for evaluation of partial volume correction techniques in brain PET/MR

    Energy Technology Data Exchange (ETDEWEB)

    Mota, Ana [Instituto de Biofísica e Engenharia Biomédica, FC-UL, Lisboa (Portugal); Institute of Nuclear Medicine, UCL, London (United Kingdom); Cuplov, Vesna [Instituto de Biofísica e Engenharia Biomédica, FC-UL, Lisboa (Portugal); Schott, Jonathan; Hutton, Brian; Thielemans, Kris [Institute of Nuclear Medicine, UCL, London (United Kingdom); Drobnjak, Ivana [Centre of Medical Image Computing, UCL, London (United Kingdom); Dickson, John [Institute of Nuclear Medicine, UCL, London (United Kingdom); Bert, Julien [INSERM UMR1101, LaTIM, CHRU de Brest, Brest (France); Burgos, Ninon; Cardoso, Jorge; Modat, Marc; Ourselin, Sebastien [Centre of Medical Image Computing, UCL, London (United Kingdom); Erlandsson, Kjell [Institute of Nuclear Medicine, UCL, London (United Kingdom)

    2015-05-18

    The Partial Volume (PV) effect in Positron Emission Tomography (PET) imaging leads to loss in quantification accuracy, which manifests in PV effects (small objects occupy partially the sensitive volume of the imaging instrument, resulting in blurred images). Simultaneous acquisition of PET and Magnetic Resonance Imaging (MRI) produces concurrent metabolic and anatomical information. The latter has proved to be very helpful for the correction of PV effects. Currently, there are several techniques used for PV correction. They can be applied directly during the reconstruction process or as a post-processing step after image reconstruction. In order to evaluate the efficacy of the different PV correction techniques in brain- PET, we are constructing a database of simulated data. Here we present the framework and steps involved in constructing this database. Static 18F-FDG epilepsy and 18F-Florbetapir amyloid dementia PET/MR were selected because of their very different characteristics. The methodology followed was based on four main steps: Image pre-processing, Ground Truth (GT) generation, MRI and PET data simulation and reconstruction. All steps used Open Source software and can therefore be repeated at any centre. The framework as well as the database will be freely accessible. Tools used included GIF, FSL, POSSUM, GATE and STIR. The final data obtained after simulation, involving raw or reconstructed PET data together with corresponding MRI datasets, were close to the original patient data. Besides, there is the advantage that data can be compared with the GT. We indicate several parameters that can be improved and optimized.

  9. Establishment of an open database of realistic simulated data for evaluation of partial volume correction techniques in brain PET/MR

    International Nuclear Information System (INIS)

    Mota, Ana; Cuplov, Vesna; Schott, Jonathan; Hutton, Brian; Thielemans, Kris; Drobnjak, Ivana; Dickson, John; Bert, Julien; Burgos, Ninon; Cardoso, Jorge; Modat, Marc; Ourselin, Sebastien; Erlandsson, Kjell

    2015-01-01

    The Partial Volume (PV) effect in Positron Emission Tomography (PET) imaging leads to loss in quantification accuracy, which manifests in PV effects (small objects occupy partially the sensitive volume of the imaging instrument, resulting in blurred images). Simultaneous acquisition of PET and Magnetic Resonance Imaging (MRI) produces concurrent metabolic and anatomical information. The latter has proved to be very helpful for the correction of PV effects. Currently, there are several techniques used for PV correction. They can be applied directly during the reconstruction process or as a post-processing step after image reconstruction. In order to evaluate the efficacy of the different PV correction techniques in brain- PET, we are constructing a database of simulated data. Here we present the framework and steps involved in constructing this database. Static 18F-FDG epilepsy and 18F-Florbetapir amyloid dementia PET/MR were selected because of their very different characteristics. The methodology followed was based on four main steps: Image pre-processing, Ground Truth (GT) generation, MRI and PET data simulation and reconstruction. All steps used Open Source software and can therefore be repeated at any centre. The framework as well as the database will be freely accessible. Tools used included GIF, FSL, POSSUM, GATE and STIR. The final data obtained after simulation, involving raw or reconstructed PET data together with corresponding MRI datasets, were close to the original patient data. Besides, there is the advantage that data can be compared with the GT. We indicate several parameters that can be improved and optimized.

  10. Metabolic impact of partial volume correction of [18F]FDG PET-CT oncological studies on the assessment of tumor response to treatment.

    Science.gov (United States)

    Stefano, A; Gallivanone, F; Messa, C; Gilardi, M C; Gastiglioni, I

    2014-12-01

    The aim of this work is to evaluate the metabolic impact of Partial Volume Correction (PVC) on the measurement of the Standard Uptake Value (SUV) from [18F]FDG PET-CT oncological studies for treatment monitoring purpose. Twenty-nine breast cancer patients with bone lesions (42 lesions in total) underwent [18F]FDG PET-CT studies after surgical resection of breast cancer primitives, and before (PET-II) chemotherapy and hormone treatment. PVC of bone lesion uptake was performed on the two [18F]FDG PET-CT studies, using a method based on Recovery Coefficients (RC) and on an automatic measurement of lesion metabolic volume. Body-weight average SUV was calculated for each lesion, with and without PVC. The accuracy, reproducibility, clinical feasibility and the metabolic impact on treatment response of the considered PVC method was evaluated. The PVC method was found clinically feasible in bone lesions, with an accuracy of 93% for lesion sphere-equivalent diameter >1 cm. Applying PVC, average SUV values increased, from 7% up to 154% considering both PET-I and PET-II studies, proving the need of the correction. As main finding, PVC modified the therapy response classification in 6 cases according to EORTC 1999 classification and in 5 cases according to PERCIST 1.0 classification. PVC has an important metabolic impact on the assessment of tumor response to treatment by [18F]FDG PET-CT oncological studies.

  11. Partial volume correction and image segmentation for accurate measurement of standardized uptake value of grey matter in the brain.

    Science.gov (United States)

    Bural, Gonca; Torigian, Drew; Basu, Sandip; Houseni, Mohamed; Zhuge, Ying; Rubello, Domenico; Udupa, Jayaram; Alavi, Abass

    2015-12-01

    Our aim was to explore a novel quantitative method [based upon an MRI-based image segmentation that allows actual calculation of grey matter, white matter and cerebrospinal fluid (CSF) volumes] for overcoming the difficulties associated with conventional techniques for measuring actual metabolic activity of the grey matter. We included four patients with normal brain MRI and fluorine-18 fluorodeoxyglucose (F-FDG)-PET scans (two women and two men; mean age 46±14 years) in this analysis. The time interval between the two scans was 0-180 days. We calculated the volumes of grey matter, white matter and CSF by using a novel segmentation technique applied to the MRI images. We measured the mean standardized uptake value (SUV) representing the whole metabolic activity of the brain from the F-FDG-PET images. We also calculated the white matter SUV from the upper transaxial slices (centrum semiovale) of the F-FDG-PET images. The whole brain volume was calculated by summing up the volumes of the white matter, grey matter and CSF. The global cerebral metabolic activity was calculated by multiplying the mean SUV with total brain volume. The whole brain white matter metabolic activity was calculated by multiplying the mean SUV for the white matter by the white matter volume. The global cerebral metabolic activity only reflects those of the grey matter and the white matter, whereas that of the CSF is zero. We subtracted the global white matter metabolic activity from that of the whole brain, resulting in the global grey matter metabolism alone. We then divided the grey matter global metabolic activity by grey matter volume to accurately calculate the SUV for the grey matter alone. The brain volumes ranged between 1546 and 1924 ml. The mean SUV for total brain was 4.8-7. Total metabolic burden of the brain ranged from 5565 to 9617. The mean SUV for white matter was 2.8-4.1. On the basis of these measurements we generated the grey matter SUV, which ranged from 8.1 to 11.3. The

  12. Quantitation of regional cerebral blood flow corrected for partial volume effect using O-15 water and PET: I. Theory, error analysis, and stereologic comparison

    DEFF Research Database (Denmark)

    Lida, H; Law, I; Pakkenberg, B

    2000-01-01

    Limited spatial resolution of positron emission tomography (PET) can cause significant underestimation in the observed regional radioactivity concentration (so-called partial volume effect or PVE) resulting in systematic errors in estimating quantitative physiologic parameters. The authors have...... formulated four mathematical models that describe the dynamic behavior of a freely diffusible tracer (H215O) in a region of interest (ROI) incorporating estimates of regional tissue flow that are independent of PVE. The current study was intended to evaluate the feasibility of these models and to establish...... a methodology to accurately quantify regional cerebral blood flow (CBF) corrected for PVE in cortical gray matter regions. Five monkeys were studied with PET after IV H2(15)O two times (n = 3) or three times (n = 2) in a row. Two ROIs were drawn on structural magnetic resonance imaging (MRI) scans and projected...

  13. SAMPL5: 3D-RISM partition coefficient calculations with partial molar volume corrections and solute conformational sampling.

    Science.gov (United States)

    Luchko, Tyler; Blinov, Nikolay; Limon, Garrett C; Joyce, Kevin P; Kovalenko, Andriy

    2016-11-01

    Implicit solvent methods for classical molecular modeling are frequently used to provide fast, physics-based hydration free energies of macromolecules. Less commonly considered is the transferability of these methods to other solvents. The Statistical Assessment of Modeling of Proteins and Ligands 5 (SAMPL5) distribution coefficient dataset and the accompanying explicit solvent partition coefficient reference calculations provide a direct test of solvent model transferability. Here we use the 3D reference interaction site model (3D-RISM) statistical-mechanical solvation theory, with a well tested water model and a new united atom cyclohexane model, to calculate partition coefficients for the SAMPL5 dataset. The cyclohexane model performed well in training and testing ([Formula: see text] for amino acid neutral side chain analogues) but only if a parameterized solvation free energy correction was used. In contrast, the same protocol, using single solute conformations, performed poorly on the SAMPL5 dataset, obtaining [Formula: see text] compared to the reference partition coefficients, likely due to the much larger solute sizes. Including solute conformational sampling through molecular dynamics coupled with 3D-RISM (MD/3D-RISM) improved agreement with the reference calculation to [Formula: see text]. Since our initial calculations only considered partition coefficients and not distribution coefficients, solute sampling provided little benefit comparing against experiment, where ionized and tautomer states are more important. Applying a simple [Formula: see text] correction improved agreement with experiment from [Formula: see text] to [Formula: see text], despite a small number of outliers. Better agreement is possible by accounting for tautomers and improving the ionization correction.

  14. SAMPL5: 3D-RISM partition coefficient calculations with partial molar volume corrections and solute conformational sampling

    Science.gov (United States)

    Luchko, Tyler; Blinov, Nikolay; Limon, Garrett C.; Joyce, Kevin P.; Kovalenko, Andriy

    2016-11-01

    Implicit solvent methods for classical molecular modeling are frequently used to provide fast, physics-based hydration free energies of macromolecules. Less commonly considered is the transferability of these methods to other solvents. The Statistical Assessment of Modeling of Proteins and Ligands 5 (SAMPL5) distribution coefficient dataset and the accompanying explicit solvent partition coefficient reference calculations provide a direct test of solvent model transferability. Here we use the 3D reference interaction site model (3D-RISM) statistical-mechanical solvation theory, with a well tested water model and a new united atom cyclohexane model, to calculate partition coefficients for the SAMPL5 dataset. The cyclohexane model performed well in training and testing (R=0.98 for amino acid neutral side chain analogues) but only if a parameterized solvation free energy correction was used. In contrast, the same protocol, using single solute conformations, performed poorly on the SAMPL5 dataset, obtaining R=0.73 compared to the reference partition coefficients, likely due to the much larger solute sizes. Including solute conformational sampling through molecular dynamics coupled with 3D-RISM (MD/3D-RISM) improved agreement with the reference calculation to R=0.93. Since our initial calculations only considered partition coefficients and not distribution coefficients, solute sampling provided little benefit comparing against experiment, where ionized and tautomer states are more important. Applying a simple pK_{ {a}} correction improved agreement with experiment from R=0.54 to R=0.66, despite a small number of outliers. Better agreement is possible by accounting for tautomers and improving the ionization correction.

  15. Feasibility and performance of novel software to quantify metabolically active volumes and 3D partial volume corrected SUV and metabolic volumetric products of spinal bone marrow metastases on 18F-FDG-PET/CT.

    Science.gov (United States)

    Torigian, Drew A; Lopez, Rosa Fernandez; Alapati, Sridevi; Bodapati, Geetha; Hofheinz, Frank; van den Hoff, Joerg; Saboury, Babak; Alavi, Abass

    2011-01-01

    Our aim was to assess feasibility and performance of novel semi-automated image analysis software called ROVER to quantify metabolically active volume (MAV), maximum standardized uptake value-maximum (SUV(max)), 3D partial volume corrected mean SUV (cSUV(mean)), and 3D partial volume corrected mean MVP (cMVP(mean)) of spinal bone marrow metastases on fluorine-18 fluorodeoxyglucose-positron emission tomography/computerized tomography ((18)F-FDG-PET/CT). We retrospectively studied 16 subjects with 31 spinal metastases on FDG-PET/CT and MRI. Manual and ROVER determinations of lesional MAV and SUV(max), and repeated ROVER measurements of MAV, SUV(max), cSUV(mean) and cMVP(mean) were made. Bland-Altman and correlation analyses were performed to assess reproducibility and agreement. Our results showed that analyses of repeated ROVER measurements revealed MAV mean difference (D)=-0.03±0.53cc (95% CI(-0.22, 0.16)), lower limit of agreement (LLOA)=-1.07cc, and upper limit of agreement (ULOA)=1.01cc; SUV(max) D=0.00±0.00 with LOAs=0.00; cSUV(mean) D=-0.01±0.39 (95% CI(-0.15, 0.13)), LLOA=-0.76, and ULOA=0.75; cMVP(mean) D=-0.52±4.78cc (95% CI(-2.23, 1.23)), LLOA=-9.89cc, and ULOA=8.86cc. Comparisons between ROVER and manual measurements revealed volume D= -0.39±1.37cc (95% CI (-0.89, 0.11)), LLOA=-3.08cc, and ULOA=2.30cc; SUV(max) D=0.00±0.00 with LOAs=0.00. Mean percent increase in lesional SUV(mean) and MVP(mean) following partial volume correction using ROVER was 84.25±36.00% and 84.45±35.94% , respectively. In conclusion, it is feasible to estimate MAV, SUV(max), cSUV(mean), and cMVP(mean) of spinal bone marrow metastases from (18)F-FDG-PET/CT quickly and easily with good reproducibility via ROVER software. Partial volume correction is imperative, as uncorrected SUV(mean) and MVP(mean) are significantly underestimated, even for large lesions. This novel approach has great potential for practical, accurate, and precise combined structural-functional PET

  16. Association between partial-volume corrected SUVmax and Oncotype DX recurrence score in early-stage, ER-positive/HER2-negative invasive breast cancer.

    Science.gov (United States)

    Lee, Su Hyun; Ha, Seunggyun; An, Hyun Joon; Lee, Jae Sung; Han, Wonshik; Im, Seock-Ah; Ryu, Han Suk; Kim, Won Hwa; Chang, Jung Min; Cho, Nariya; Moon, Woo Kyung; Cheon, Gi Jeong

    2016-08-01

    Oncotype DX, a 21-gene expression assay, provides a recurrence score (RS) which predicts prognosis and the benefit from adjuvant chemotherapy in patients with early-stage, estrogen receptor-positive (ER-positive), and human epidermal growth factor receptor 2-negative (HER2-negative) invasive breast cancer. However, Oncotype DX tests are expensive and not readily available in all institutions. The purpose of this study was to investigate whether metabolic parameters on (18)F-FDG PET/CT are associated with the Oncotype DX RS and whether (18)F-FDG PET/CT can be used to predict the Oncotype DX RS. The study group comprised 38 women with stage I/II, ER-positive/HER2-negative invasive breast cancer who underwent pretreatment (18)F-FDG PET/CT and Oncotype DX testing. On PET/CT, maximum (SUVmax) and average standardized uptake values, metabolic tumor volume, and total lesion glycolysis were measured. Partial volume-corrected SUVmax (PVC-SUVmax) determined using the recovery coefficient method was also evaluated. Oncotype DX RS (0 - 100) was categorized as low (negative breast cancer.

  17. Partial volume effect in MRI

    International Nuclear Information System (INIS)

    Maeda, Munehiro; Yoshiya, Kazuhiko; Suzuki, Eiji

    1989-01-01

    According to the direction and the thickness of the imaging slice in tomography, the border between the tissues becomes unclear (partial volume effect). In the present MRI experiment, we examined border area between fat and water components using phantom in order to investigate the partial volume effect in MRI. In spin echo sequences, the intensity of the border area showed a linear relationship with composition of fat and water. Whereas, in inversion recovery and field echo sequences, we found the parameters to produce an extremely low intensity area at the border region between fat and water. This low intensity area was explained by cancellation of NMR signals from fat and water due to the difference in the direction of magnetic vectors. Clinically, partial volume effect can cause of mis-evaluation of walls, small nodules, tumor capsules and the tumor invasion in the use of inversion recovery and field echo sequences. (author)

  18. Impact of motion compensation and partial volume correction for 18F-NaF PET/CT imaging of coronary plaque

    Science.gov (United States)

    Cal-González, J.; Tsoumpas, C.; Lassen, M. L.; Rasul, S.; Koller, L.; Hacker, M.; Schäfers, K.; Beyer, T.

    2018-01-01

    Recent studies have suggested that 18F-NaF-PET enables visualization and quantification of plaque micro-calcification in the coronary tree. However, PET imaging of plaque calcification in the coronary arteries is challenging because of the respiratory and cardiac motion as well as partial volume effects. The objective of this work is to implement an image reconstruction framework, which incorporates compensation for respiratory as well as cardiac motion (MoCo) and partial volume correction (PVC), for cardiac 18F-NaF PET imaging in PET/CT. We evaluated the effect of MoCo and PVC on the quantification of vulnerable plaques in the coronary arteries. Realistic simulations (Biograph TPTV, Biograph mCT) and phantom acquisitions (Biograph mCT) were used for these evaluations. Different uptake values in the calcified plaques were evaluated in the simulations, while three ‘plaque-type’ lesions of 36, 31 and 18 mm3 were included in the phantom experiments. After validation, the MoCo and PVC methods were applied in four pilot NaF-PET patient studies. In all cases, the MoCo-based image reconstruction was performed using the STIR software. The PVC was obtained from a local projection (LP) method, previously evaluated in preclinical and clinical PET. The results obtained show a significant increase of the measured lesion-to-background ratios (LBR) in the MoCo  +  PVC images. These ratios were further enhanced when using directly the tissue-activities from the LP method, making this approach more suitable for the quantitative evaluation of coronary plaques. When using the LP method on the MoCo images, LBR increased between 200% and 1119% in the simulated data, between 212% and 614% in the phantom experiments and between 46% and 373% in the plaques with positive uptake observed in the pilot patients. In conclusion, we have built and validated a STIR framework incorporating MoCo and PVC for 18F-NaF PET imaging of coronary plaques. First results indicate an improved

  19. An improved optimization algorithm of the three-compartment model with spillover and partial volume corrections for dynamic FDG PET images of small animal hearts in vivo

    Science.gov (United States)

    Li, Yinlin; Kundu, Bijoy K.

    2018-03-01

    The three-compartment model with spillover (SP) and partial volume (PV) corrections has been widely used for noninvasive kinetic parameter studies of dynamic 2-[18F] fluoro-2deoxy-D-glucose (FDG) positron emission tomography images of small animal hearts in vivo. However, the approach still suffers from estimation uncertainty or slow convergence caused by the commonly used optimization algorithms. The aim of this study was to develop an improved optimization algorithm with better estimation performance. Femoral artery blood samples, image-derived input functions from heart ventricles and myocardial time-activity curves (TACs) were derived from data on 16 C57BL/6 mice obtained from the UCLA Mouse Quantitation Program. Parametric equations of the average myocardium and the blood pool TACs with SP and PV corrections in a three-compartment tracer kinetic model were formulated. A hybrid method integrating artificial immune-system and interior-reflective Newton methods were developed to solve the equations. Two penalty functions and one late time-point tail vein blood sample were used to constrain the objective function. The estimation accuracy of the method was validated by comparing results with experimental values using the errors in the areas under curves (AUCs) of the model corrected input function (MCIF) and the 18F-FDG influx constant K i . Moreover, the elapsed time was used to measure the convergence speed. The overall AUC error of MCIF for the 16 mice averaged  -1.4  ±  8.2%, with correlation coefficients of 0.9706. Similar results can be seen in the overall K i error percentage, which was 0.4  ±  5.8% with a correlation coefficient of 0.9912. The t-test P value for both showed no significant difference. The mean and standard deviation of the MCIF AUC and K i percentage errors have lower values compared to the previously published methods. The computation time of the hybrid method is also several times lower than using just a stochastic

  20. Correction for Partial Volume Effect Is a Must, Not a Luxury, to Fully Exploit the Potential of Quantitative PET Imaging in Clinical Oncology

    DEFF Research Database (Denmark)

    Alavi, Abass; Werner, Thomas J; Høilund-Carlsen, Poul Flemming

    2018-01-01

    The partial volume effect (PVE) is considered as one of the major degrading factors impacting image quality and hampering the accuracy of quantitative PET imaging in clinical oncology. This effect is the consequence of the limited spatial resolution of whole-body PET scanners, which results in bl...

  1. Database of normal human cerebral blood flow measured by SPECT: II. Quantification of I-123-IMP studies with ARG method and effects of partial volume correction.

    Science.gov (United States)

    Inoue, Kentaro; Ito, Hiroshi; Shidahara, Miho; Goto, Ryoi; Kinomura, Shigeo; Sato, Kazunori; Taki, Yasuyuki; Okada, Ken; Kaneta, Tomohiro; Fukuda, Hiroshi

    2006-02-01

    The limited spatial resolution of SPECT causes a partial volume effect (PVE) and can lead to the significant underestimation of regional tracer concentration in the small structures surrounded by a low tracer concentration, such as the cortical gray matter of an atrophied brain. The aim of the present study was to determine, using 123I-IMP and SPECT, normal CBF of elderly subjects with and without PVE correction (PVC), and to determine regional differences in the effect of PVC and their association with the regional tissue fraction of the brain. Quantitative CBF SPECT using 123I-IMP was performed in 33 healthy elderly subjects (18 males, 15 females, 54-74 years old) using the autoradiographic method. We corrected CBF for PVE using segmented MR images, and analyzed quantitative CBF and regional differences in the effect of PVC using tissue fractions of gray matter (GM) and white matter (WM) in regions of interest (ROIs) placed on the cortical and subcortical GM regions and deep WM regions. The mean CBF in GM-ROIs were 31.7 +/- 6.6 and 41.0 +/- 8.1 ml/100 g/min for males and females, and in WM-ROIs, 18.2 +/- 0.7 and 22.9 +/- 0.8 ml/100 g/min for males and females, respectively. The mean CBF in GM-ROIs after PVC were 50.9 +/- 12.8 and 65.8 +/- 16.1 ml/100 g/min for males and females, respectively. There were statistically significant differences in the effect of PVC among ROIs, but not between genders. The effect of PVC was small in the cerebellum and parahippocampal gyrus, and it was large in the superior frontal gyrus, superior parietal lobule and precentral gyrus. Quantitative CBF in GM recovered significantly, but did not reach values as high as those obtained by invasive methods or in the H2(15)O PET study that used PVC. There were significant regional differences in the effect of PVC, which were considered to result from regional differences in GM tissue fraction, which is more reduced in the frontoparietal regions in the atrophied brain of the elderly.

  2. Database of normal human cerebral blood flow measured by SPECT. II. Quantification of I-123-IMP studies with ARG method and effects of partial volume correction

    International Nuclear Information System (INIS)

    Inoue, Kentaro; Ito, Hiroshi; Shidahara, Miho

    2006-01-01

    The limited spatial resolution of SPECT causes a partial volume effect (PVE) and can lead to the significant underestimation of regional tracer concentration in the small structures surrounded by a low tracer concentration, such as the cortical gray matter of an atrophied brain. The aim of the present study was to determine, using 123 I-IMP and SPECT, normal cerebral blood flow (CBF) of elderly subjects with and without PVE correction (PVC), and to determine regional differences in the effect of PVC and their association with the regional tissue fraction of the brain. Quantitative CBF SPECT using 123 I-IMP was performed in 33 healthy elderly subjects (18 males, 15 females, 54-74 years old) using the autoradiographic method. We corrected CBF for PVE using segmented MR images, and analyzed quantitative CBF and regional differences in the effect of PVC using tissue fractions of gray matter (GM) and white matter (WM) in regions of interest (ROIs) placed on the cortical and subcortical GM regions and deep WM regions. The mean CBF in GM-ROIs were 31.7±6.6 and 41.0±8.1 ml/100 g/min for males and females, and in WM-ROIs, 18.2±0.7 and 22.9±0.8 ml/100 g/min for males and females, respectively. The mean CBF in GM-ROIs after PVC were 50.9±12.8 and 65.8±16.1 ml/100 g/min for males and females, respectively. There were statistically significant differences in the effect of PVC among ROIs, but not between genders. The effect of PVC was small in the cerebellum and parahippocampal gyrus, and it was large in the superior frontal gyrus, superior parietal lobule and precentral gyrus. Quantitative CBF in GM recovered significantly, but did not reach values as high as those obtained by invasive methods or in the H 2 15 O PET study that used PVC. There were significant regional differences in the effect of PVC, which were considered to result from regional differences in GM tissue fraction, which is more reduced in the frontoparietal regions in the atrophied brain of the elderly

  3. When structure affects function--the need for partial volume effect correction in functional and resting state magnetic resonance imaging studies.

    Science.gov (United States)

    Dukart, Juergen; Bertolino, Alessandro

    2014-01-01

    Both functional and also more recently resting state magnetic resonance imaging have become established tools to investigate functional brain networks. Most studies use these tools to compare different populations without controlling for potential differences in underlying brain structure which might affect the functional measurements of interest. Here, we adapt a simulation approach combined with evaluation of real resting state magnetic resonance imaging data to investigate the potential impact of partial volume effects on established functional and resting state magnetic resonance imaging analyses. We demonstrate that differences in the underlying structure lead to a significant increase in detected functional differences in both types of analyses. Largest increases in functional differences are observed for highest signal-to-noise ratios and when signal with the lowest amount of partial volume effects is compared to any other partial volume effect constellation. In real data, structural information explains about 25% of within-subject variance observed in degree centrality--an established resting state connectivity measurement. Controlling this measurement for structural information can substantially alter correlational maps obtained in group analyses. Our results question current approaches of evaluating these measurements in diseased population with known structural changes without controlling for potential differences in these measurements.

  4. Influence of the partial volume correction method on (18)F-fluorodeoxyglucose brain kinetic modelling from dynamic PET images reconstructed with resolution model based OSEM.

    Science.gov (United States)

    Bowen, Spencer L; Byars, Larry G; Michel, Christian J; Chonde, Daniel B; Catana, Ciprian

    2013-10-21

    Kinetic parameters estimated from dynamic (18)F-fluorodeoxyglucose ((18)F-FDG) PET acquisitions have been used frequently to assess brain function in humans. Neglecting partial volume correction (PVC) for a dynamic series has been shown to produce significant bias in model estimates. Accurate PVC requires a space-variant model describing the reconstructed image spatial point spread function (PSF) that accounts for resolution limitations, including non-uniformities across the field of view due to the parallax effect. For ordered subsets expectation maximization (OSEM), image resolution convergence is local and influenced significantly by the number of iterations, the count density, and background-to-target ratio. As both count density and background-to-target values for a brain structure can change during a dynamic scan, the local image resolution may also concurrently vary. When PVC is applied post-reconstruction the kinetic parameter estimates may be biased when neglecting the frame-dependent resolution. We explored the influence of the PVC method and implementation on kinetic parameters estimated by fitting (18)F-FDG dynamic data acquired on a dedicated brain PET scanner and reconstructed with and without PSF modelling in the OSEM algorithm. The performance of several PVC algorithms was quantified with a phantom experiment, an anthropomorphic Monte Carlo simulation, and a patient scan. Using the last frame reconstructed image only for regional spread function (RSF) generation, as opposed to computing RSFs for each frame independently, and applying perturbation geometric transfer matrix PVC with PSF based OSEM produced the lowest magnitude bias kinetic parameter estimates in most instances, although at the cost of increased noise compared to the PVC methods utilizing conventional OSEM. Use of the last frame RSFs for PVC with no PSF modelling in the OSEM algorithm produced the lowest bias in cerebral metabolic rate of glucose estimates, although by less than 5% in

  5. Partial Molar Volumes of Aqua Ions from First Principles.

    Science.gov (United States)

    Wiktor, Julia; Bruneval, Fabien; Pasquarello, Alfredo

    2017-08-08

    Partial molar volumes of ions in water solution are calculated through pressures obtained from ab initio molecular dynamics simulations. The correct definition of pressure in charged systems subject to periodic boundary conditions requires access to the variation of the electrostatic potential upon a change of volume. We develop a scheme for calculating such a variation in liquid systems by setting up an interface between regions of different density. This also allows us to determine the absolute deformation potentials for the band edges of liquid water. With the properly defined pressures, we obtain partial molar volumes of a series of aqua ions in very good agreement with experimental values.

  6. Anatomy-based reconstruction of FDG-PET images with implicit partial volume correction improves detection of hypometabolic regions in patients with epilepsy due to focal cortical dysplasia diagnosed on MRI

    International Nuclear Information System (INIS)

    Goffin, Karolien; Baete, Kristof; Nuyts, Johan; Laere, Koen van; Van Paesschen, Wim; Dupont, Patrick; Palmini, Andre

    2010-01-01

    Detection of hypometabolic areas on interictal FDG-PET images for assessing the epileptogenic zone is hampered by partial volume effects. We evaluated the performance of an anatomy-based maximum a-posteriori (A-MAP) reconstruction algorithm which combined noise suppression with correction for the partial volume effect in the detection of hypometabolic areas in patients with focal cortical dysplasia (FCD). FDG-PET images from 14 patients with refractory partial epilepsy were reconstructed using A-MAP and maximum likelihood (ML) reconstruction. In all patients, presurgical evaluation showed that FCD represented the epileptic lesion. Correspondence between the FCD location and regional metabolism on a predefined atlas was evaluated. An asymmetry index of FCD to normal cortex was calculated. Hypometabolism at the FCD location was detected in 9/14 patients (64%) using ML and in 10/14 patients (71%) using A-MAP reconstruction. Hypometabolic areas outside the FCD location were detected in 12/14 patients (86%) using ML and in 11/14 patients (79%) using A-MAP reconstruction. The asymmetry index was higher using A-MAP reconstruction (0.61, ML 0.49, p=0.03). The A-MAP reconstruction algorithm improved visual detection of epileptic FCD on brain FDG-PET images compared to ML reconstruction, due to higher contrast and better delineation of the lesion. This improvement failed to reach significance in our small sample. Hypometabolism outside the lesion is often present, consistent with the observation that the functional deficit zone tends to be larger than the epileptogenic zone. (orig.)

  7. Anatomy-based reconstruction of FDG-PET images with implicit partial volume correction improves detection of hypometabolic regions in patients with epilepsy due to focal cortical dysplasia diagnosed on MRI

    Energy Technology Data Exchange (ETDEWEB)

    Goffin, Karolien; Baete, Kristof; Nuyts, Johan; Laere, Koen van [University Hospital Leuven, Division of Nuclear Medicine and Medical Imaging Center, Leuven (Belgium); Van Paesschen, Wim [University Hospital Leuven, Neurology Department, Leuven (Belgium); Dupont, Patrick [University Hospital Leuven, Division of Nuclear Medicine and Medical Imaging Center, Leuven (Belgium); University Hospital Leuven, Laboratory of Cognitive Neurology, Leuven (Belgium); Palmini, Andre [Pontificia Universidade Catolica do Rio Grande do Sul (PUCRS), Porto Alegre Epilepsy Surgery Program, Hospital Sao Lucas, Porto Alegre (Brazil)

    2010-06-15

    Detection of hypometabolic areas on interictal FDG-PET images for assessing the epileptogenic zone is hampered by partial volume effects. We evaluated the performance of an anatomy-based maximum a-posteriori (A-MAP) reconstruction algorithm which combined noise suppression with correction for the partial volume effect in the detection of hypometabolic areas in patients with focal cortical dysplasia (FCD). FDG-PET images from 14 patients with refractory partial epilepsy were reconstructed using A-MAP and maximum likelihood (ML) reconstruction. In all patients, presurgical evaluation showed that FCD represented the epileptic lesion. Correspondence between the FCD location and regional metabolism on a predefined atlas was evaluated. An asymmetry index of FCD to normal cortex was calculated. Hypometabolism at the FCD location was detected in 9/14 patients (64%) using ML and in 10/14 patients (71%) using A-MAP reconstruction. Hypometabolic areas outside the FCD location were detected in 12/14 patients (86%) using ML and in 11/14 patients (79%) using A-MAP reconstruction. The asymmetry index was higher using A-MAP reconstruction (0.61, ML 0.49, p=0.03). The A-MAP reconstruction algorithm improved visual detection of epileptic FCD on brain FDG-PET images compared to ML reconstruction, due to higher contrast and better delineation of the lesion. This improvement failed to reach significance in our small sample. Hypometabolism outside the lesion is often present, consistent with the observation that the functional deficit zone tends to be larger than the epileptogenic zone. (orig.)

  8. Applications of tissue heterogeneity corrections and biologically effective dose volume histograms in assessing the doses for accelerated partial breast irradiation using an electronic brachytherapy source

    Science.gov (United States)

    Shi, Chengyu; Guo, Bingqi; Cheng, Chih-Yao; Eng, Tony; Papanikolaou, Nikos

    2010-09-01

    A low-energy electronic brachytherapy source (EBS), the model S700 Axxent™ x-ray device developed by Xoft Inc., has been used in high dose rate (HDR) intracavitary accelerated partial breast irradiation (APBI) as an alternative to an Ir-192 source. The prescription dose and delivery schema of the electronic brachytherapy APBI plan are the same as the Ir-192 plan. However, due to its lower mean energy than the Ir-192 source, an EBS plan has dosimetric and biological features different from an Ir-192 source plan. Current brachytherapy treatment planning methods may have large errors in treatment outcome prediction for an EBS plan. Two main factors contribute to the errors: the dosimetric influence of tissue heterogeneities and the enhancement of relative biological effectiveness (RBE) of electronic brachytherapy. This study quantified the effects of these two factors and revisited the plan quality of electronic brachytherapy APBI. The influence of tissue heterogeneities is studied by a Monte Carlo method and heterogeneous 'virtual patient' phantoms created from CT images and structure contours; the effect of RBE enhancement in the treatment outcome was estimated by biologically effective dose (BED) distribution. Ten electronic brachytherapy APBI cases were studied. The results showed that, for electronic brachytherapy cases, tissue heterogeneities and patient boundary effect decreased dose to the target and skin but increased dose to the bones. On average, the target dose coverage PTV V100 reduced from 95.0% in water phantoms (planned) to only 66.7% in virtual patient phantoms (actual). The actual maximum dose to the ribs is 3.3 times higher than the planned dose; the actual mean dose to the ipsilateral breast and maximum dose to the skin were reduced by 22% and 17%, respectively. Combining the effect of tissue heterogeneities and RBE enhancement, BED coverage of the target was 89.9% in virtual patient phantoms with RBE enhancement (actual BED) as compared to 95

  9. Applications of tissue heterogeneity corrections and biologically effective dose volume histograms in assessing the doses for accelerated partial breast irradiation using an electronic brachytherapy source

    Energy Technology Data Exchange (ETDEWEB)

    Shi Chengyu; Guo Bingqi; Eng, Tony; Papanikolaou, Nikos [Cancer Therapy and Research Center, University of Texas Health Science Center at San Antonio, TX 78229 (United States); Cheng, Chih-Yao, E-mail: shic@uthscsa.ed [Radiation Oncology Department, Oklahoma University Health Science Center, Oklahoma, OK 73104 (United States)

    2010-09-21

    A low-energy electronic brachytherapy source (EBS), the model S700 Axxent(TM) x-ray device developed by Xoft Inc., has been used in high dose rate (HDR) intracavitary accelerated partial breast irradiation (APBI) as an alternative to an Ir-192 source. The prescription dose and delivery schema of the electronic brachytherapy APBI plan are the same as the Ir-192 plan. However, due to its lower mean energy than the Ir-192 source, an EBS plan has dosimetric and biological features different from an Ir-192 source plan. Current brachytherapy treatment planning methods may have large errors in treatment outcome prediction for an EBS plan. Two main factors contribute to the errors: the dosimetric influence of tissue heterogeneities and the enhancement of relative biological effectiveness (RBE) of electronic brachytherapy. This study quantified the effects of these two factors and revisited the plan quality of electronic brachytherapy APBI. The influence of tissue heterogeneities is studied by a Monte Carlo method and heterogeneous 'virtual patient' phantoms created from CT images and structure contours; the effect of RBE enhancement in the treatment outcome was estimated by biologically effective dose (BED) distribution. Ten electronic brachytherapy APBI cases were studied. The results showed that, for electronic brachytherapy cases, tissue heterogeneities and patient boundary effect decreased dose to the target and skin but increased dose to the bones. On average, the target dose coverage PTV V{sub 100} reduced from 95.0% in water phantoms (planned) to only 66.7% in virtual patient phantoms (actual). The actual maximum dose to the ribs is 3.3 times higher than the planned dose; the actual mean dose to the ipsilateral breast and maximum dose to the skin were reduced by 22% and 17%, respectively. Combining the effect of tissue heterogeneities and RBE enhancement, BED coverage of the target was 89.9% in virtual patient phantoms with RBE enhancement (actual BED) as

  10. Applications of tissue heterogeneity corrections and biologically effective dose volume histograms in assessing the doses for accelerated partial breast irradiation using an electronic brachytherapy source

    International Nuclear Information System (INIS)

    Shi Chengyu; Guo Bingqi; Eng, Tony; Papanikolaou, Nikos; Cheng, Chih-Yao

    2010-01-01

    A low-energy electronic brachytherapy source (EBS), the model S700 Axxent(TM) x-ray device developed by Xoft Inc., has been used in high dose rate (HDR) intracavitary accelerated partial breast irradiation (APBI) as an alternative to an Ir-192 source. The prescription dose and delivery schema of the electronic brachytherapy APBI plan are the same as the Ir-192 plan. However, due to its lower mean energy than the Ir-192 source, an EBS plan has dosimetric and biological features different from an Ir-192 source plan. Current brachytherapy treatment planning methods may have large errors in treatment outcome prediction for an EBS plan. Two main factors contribute to the errors: the dosimetric influence of tissue heterogeneities and the enhancement of relative biological effectiveness (RBE) of electronic brachytherapy. This study quantified the effects of these two factors and revisited the plan quality of electronic brachytherapy APBI. The influence of tissue heterogeneities is studied by a Monte Carlo method and heterogeneous 'virtual patient' phantoms created from CT images and structure contours; the effect of RBE enhancement in the treatment outcome was estimated by biologically effective dose (BED) distribution. Ten electronic brachytherapy APBI cases were studied. The results showed that, for electronic brachytherapy cases, tissue heterogeneities and patient boundary effect decreased dose to the target and skin but increased dose to the bones. On average, the target dose coverage PTV V 100 reduced from 95.0% in water phantoms (planned) to only 66.7% in virtual patient phantoms (actual). The actual maximum dose to the ribs is 3.3 times higher than the planned dose; the actual mean dose to the ipsilateral breast and maximum dose to the skin were reduced by 22% and 17%, respectively. Combining the effect of tissue heterogeneities and RBE enhancement, BED coverage of the target was 89.9% in virtual patient phantoms with RBE enhancement (actual BED) as compared to 95

  11. Computing the partial volume of pressure vessels

    Energy Technology Data Exchange (ETDEWEB)

    Wiencke, Bent [Nestle USA, Corporate Engineering, 800 N. Brand Blvd, Glendale, CA 91203 (United States)

    2010-06-15

    The computation of the partial and total volume of pressure vessels with various type of head profiles requires detailed knowledge of the head profile geometry. Depending on the type of head profile the derivation of the equations can become very complex and the calculation process cumbersome. Certain head profiles require numerical methods to obtain the partial volume, which for most application is beyond the scope of practicability. This paper suggests a unique method that simplifies the calculation procedure for the various types of head profiles by using one common set of equations without the need for numerical or complex computation methods. For ease of use, all equations presented in this paper are summarized in a single table format for horizontal and vertical vessels. (author)

  12. Semantics and correctness proofs for programs with partial functions

    International Nuclear Information System (INIS)

    Yakhnis, A.; Yakhnis, V.

    1996-01-01

    This paper presents a portion of the work on specification, design, and implementation of safety-critical systems such as reactor control systems. A natural approach to this problem, once all the requirements are captured, would be to state the requirements formally and then either to prove (preferably via automated tools) that the system conforms to spec (program verification), or to try to simultaneously generate the system and a mathematical proof that the requirements are being met (program derivation). An obstacle to this is frequent presence of partially defined operations within the software and its specifications. Indeed, the usual proofs via first order logic presuppose everywhere defined operations. Recognizing this problem, David Gries, in ''The Science of Programming,'' 1981, introduced the concept of partial functions into the mainstream of program correctness and gave hints how his treatment of partial functions could be formalized. Still, however, existing theorem provers and software verifiers have difficulties in checking software with partial functions, because of absence of uniform first order treatment of partial functions within classical 2-valued logic. Several rigorous mechanisms that took partiality into account were introduced [Wirsing 1990, Breu 1991, VDM 1986, 1990, etc.]. However, they either did not discuss correctness proofs or departed from first order logic. To fill this gap, the authors provide a semantics for software correctness proofs with partial functions within classical 2-valued 1st order logic. They formalize the Gries treatment of partial functions and also cover computations of functions whose argument lists may be only partially available. An example is nuclear reactor control relying on sensors which may fail to deliver sense data. This approach is sufficiently general to cover correctness proofs in various implementation languages

  13. Correction volumes and densities in Vitrea Program

    International Nuclear Information System (INIS)

    Abrantes, Marcos E.S.; Oliveira, A.H. de

    2014-01-01

    Introduction: with the increased use of 3D reconstruction techniques to assist in diagnosis, Vitrea® program is widely used. To use this program you need to know the correction values to generate the volumes and number of real CT human tissues. Objective: provide correction values for volumes and number of CT, read the Vitrea program, of the tissues generated by DICOM images from CT. Methodology: this study used a PMMA chest phantom to generate the DICOM images on a scanner. To check the calibration of the scanner was used Catphan phantom and compared the manufacturer of the values associated with its straight linearity. Results: the volume of PMMA phantom was of 11166.58 cm³ and CT number (123.5 ± 33.4) UH. For the volume found in Vitrea program, according to the structures of interest, were 11897.29 cm 3 , 10901.65 cm³, 16906.49 cm 3 and 11848.34 cm³ and corrections values are -6.14%, + 2.43% -6.94% -5.75% respectively for the tissues: lung, bone, soft and full. For the CT numbers found in this program were (97.60 ± 58.9) UH, (72.00 ± 176.00) UH, (143.20 ± 19.50) UH and (31.90 ± 239,10) UH and corrections of + 26.54%, + 71.53%, -13.64% and 387.15% respectively for tissues: lung, bone, soft and full. Conclusion: the procedure performed can be used in other 3D reconstruction programs and where there are tools to reading CT number, observing the necessary corrections

  14. Adaptive partial volume classification of MRI data

    International Nuclear Information System (INIS)

    Chiverton, John P; Wells, Kevin

    2008-01-01

    Tomographic biomedical images are commonly affected by an imaging artefact known as the partial volume (PV) effect. The PV effect produces voxels composed of a mixture of tissues in anatomical magnetic resonance imaging (MRI) data resulting in a continuity of these tissue classes. Anatomical MRI data typically consist of a number of contiguous regions of tissues or even contiguous regions of PV voxels. Furthermore discontinuities exist between the boundaries of these contiguous image regions. The work presented here probabilistically models the PV effect using spatial regularization in the form of continuous Markov random fields (MRFs) to classify anatomical MRI brain data, simulated and real. A unique approach is used to adaptively control the amount of spatial regularization imposed by the MRF. Spatially derived image gradient magnitude is used to identify the discontinuities between image regions of contiguous tissue voxels and PV voxels, imposing variable amounts of regularization determined by simulation. Markov chain Monte Carlo (MCMC) is used to simulate the posterior distribution of the probabilistic image model. Promising quantitative results are presented for PV classification of simulated and real MRI data of the human brain.

  15. Quantitation of regional cerebral blood flow corrected for partial volume effect using O-15 water and PET: II. Normal values and gray matter blood flow response to visual activation

    DEFF Research Database (Denmark)

    Law, I; Iida, H; Holm, S

    2000-01-01

    One of the most limiting factors for the accurate quantification of physiologic parameters with positron emission tomography (PET) is the partial volume effect (PVE). To assess the magnitude of this contribution to the measurement of regional cerebral blood flow (rCBF), the authors have formulated...... or 3D). Furthermore, the authors wanted to measure the activation response in the occipital gray matter compartment, and in doing so test the stability of the PTF, during perturbations of rCBF induced by visual stimulation. Eight dynamic PET scans were acquired per subject (n = 8), each for a duration...... of 6 minutes after IV bolus injection of H2(15)O. Four of these scans were performed using 2D and four using 3D acquisition. Visual stimulation was presented in four scans, and four scans were during rest. Model C was found optimal based on Akaike's Information Criteria (AIC) and had the smallest...

  16. Volume correction factor in time dose relationships in brachytherapy

    International Nuclear Information System (INIS)

    Supe, S.J.; Sasane, J.B.

    1987-01-01

    Paterson's clinical data about the maximum tolerance doses for various volumes of interstitial implants with Ra-226 delivered in seven days was made use of in deriving volume correction factors for TDF and CRE concepts respectively for brachytherapy. The derived volume correction factors for TDF and for CRE differ fromthe one assumed for CRE by Kirk et al. and implied for TDF by Goitein. A normalising volume of 70 cc has been suggested for both CRE and TDF concepts for brachytherapy. A table showing the volume corrected TDF is presented for various volumes and dose rates for continuous irradiation. The use of this table is illustrated with examples. (orig.) [de

  17. Quantification of brain tissue through incorporation of partial volume effects

    Science.gov (United States)

    Gage, Howard D.; Santago, Peter, II; Snyder, Wesley E.

    1992-06-01

    This research addresses the problem of automatically quantifying the various types of brain tissue, CSF, white matter, and gray matter, using T1-weighted magnetic resonance images. The method employs a statistical model of the noise and partial volume effect and fits the derived probability density function to that of the data. Following this fit, the optimal decision points can be found for the materials and thus they can be quantified. Emphasis is placed on repeatable results for which a confidence in the solution might be measured. Results are presented assuming a single Gaussian noise source and a uniform distribution of partial volume pixels for both simulated and actual data. Thus far results have been mixed, with no clear advantage being shown in taking into account partial volume effects. Due to the fitting problem being ill-conditioned, it is not yet clear whether these results are due to problems with the model or the method of solution.

  18. Partial Molar Volume of Methanol in Water: Effect of Polarizability

    Czech Academy of Sciences Publication Activity Database

    Moučka, F.; Nezbeda, Ivo

    2009-01-01

    Roč. 74, č. 4 (2009), s. 559-563 ISSN 0010-0765 R&D Projects: GA AV ČR IAA400720802 Institutional research plan: CEZ:AV0Z40720504 Keywords : water–methanol mixtures * partial molar volume * polarizability Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 0.856, year: 2009

  19. Determination of partial molar volumes from free energy perturbation theory.

    Science.gov (United States)

    Vilseck, Jonah Z; Tirado-Rives, Julian; Jorgensen, William L

    2015-04-07

    Partial molar volume is an important thermodynamic property that gives insights into molecular size and intermolecular interactions in solution. Theoretical frameworks for determining the partial molar volume (V°) of a solvated molecule generally apply Scaled Particle Theory or Kirkwood-Buff theory. With the current abilities to perform long molecular dynamics and Monte Carlo simulations, more direct methods are gaining popularity, such as computing V° directly as the difference in computed volume from two simulations, one with a solute present and another without. Thermodynamically, V° can also be determined as the pressure derivative of the free energy of solvation in the limit of infinite dilution. Both approaches are considered herein with the use of free energy perturbation (FEP) calculations to compute the necessary free energies of solvation at elevated pressures. Absolute and relative partial molar volumes are computed for benzene and benzene derivatives using the OPLS-AA force field. The mean unsigned error for all molecules is 2.8 cm(3) mol(-1). The present methodology should find use in many contexts such as the development and testing of force fields for use in computer simulations of organic and biomolecular systems, as a complement to related experimental studies, and to develop a deeper understanding of solute-solvent interactions.

  20. Determination of partial molar volumes from free energy perturbation theory†

    Science.gov (United States)

    Vilseck, Jonah Z.; Tirado-Rives, Julian

    2016-01-01

    Partial molar volume is an important thermodynamic property that gives insights into molecular size and intermolecular interactions in solution. Theoretical frameworks for determining the partial molar volume (V°) of a solvated molecule generally apply Scaled Particle Theory or Kirkwood–Buff theory. With the current abilities to perform long molecular dynamics and Monte Carlo simulations, more direct methods are gaining popularity, such as computing V° directly as the difference in computed volume from two simulations, one with a solute present and another without. Thermodynamically, V° can also be determined as the pressure derivative of the free energy of solvation in the limit of infinite dilution. Both approaches are considered herein with the use of free energy perturbation (FEP) calculations to compute the necessary free energies of solvation at elevated pressures. Absolute and relative partial molar volumes are computed for benzene and benzene derivatives using the OPLS-AA force field. The mean unsigned error for all molecules is 2.8 cm3 mol−1. The present methodology should find use in many contexts such as the development and testing of force fields for use in computer simulations of organic and biomolecular systems, as a complement to related experimental studies, and to develop a deeper understanding of solute–solvent interactions. PMID:25589343

  1. Detecting and correcting partial errors: Evidence for efficient control without conscious access.

    Science.gov (United States)

    Rochet, N; Spieser, L; Casini, L; Hasbroucq, T; Burle, B

    2014-09-01

    Appropriate reactions to erroneous actions are essential to keeping behavior adaptive. Erring, however, is not an all-or-none process: electromyographic (EMG) recordings of the responding muscles have revealed that covert incorrect response activations (termed "partial errors") occur on a proportion of overtly correct trials. The occurrence of such "partial errors" shows that incorrect response activations could be corrected online, before turning into overt errors. In the present study, we showed that, unlike overt errors, such "partial errors" are poorly consciously detected by participants, who could report only one third of their partial errors. Two parameters of the partial errors were found to predict detection: the surface of the incorrect EMG burst (larger for detected) and the correction time (between the incorrect and correct EMG onsets; longer for detected). These two parameters provided independent information. The correct(ive) responses associated with detected partial errors were larger than the "pure-correct" ones, and this increase was likely a consequence, rather than a cause, of the detection. The respective impacts of the two parameters predicting detection (incorrect surface and correction time), along with the underlying physiological processes subtending partial-error detection, are discussed.

  2. Partial drift volume due to a self-propelled swimmer

    Science.gov (United States)

    Chisholm, Nicholas G.; Khair, Aditya S.

    2018-01-01

    We assess the ability of a self-propelled swimmer to displace a volume of fluid that is large compared to its own volume via the mechanism of partial drift. The swimmer performs rectilinear locomotion in an incompressible, unbounded Newtonian fluid. The partial drift volume D is the volume of fluid enclosed between the initial and final profiles of an initially flat circular disk of marked fluid elements; the disk is initially aligned perpendicular to the direction of locomotion and subsequently distorted due to the passage of the swimmer, which travels a finite distance. To focus on the possibility of large-scale drift, we model the swimmer simply as a force dipole aligned with the swimming direction. At zero Reynolds number (Re =0 ), we demonstrate that D grows without limit as the radius of the marked fluid disk h is made large, indicating that a swimmer at Re =0 can generate a partial drift volume much larger than its own volume. Next, we consider a steady swimmer at small Re , which is modeled as the force-dipole solution to Oseen's equation. Here, we find that D no longer diverges with h , which is due to inertial screening of viscous forces, and is effectively proportional to the magnitude of the force dipole exerted by the swimmer. The validity of this result is extended to Re ≥O (1 ) —the realm of intermediate-Re swimmers such as copepods—by taking advantage of the fact that, in this case, the flow is also described by Oseen's equations at distances much larger than the characteristic linear dimension of the swimmer. Next, we utilize an integral momentum balance to demonstrate that our analysis for a steady inertial swimmer also holds, in a time-averaged sense, for an unsteady swimmer that does not experience a net acceleration over a stroke cycle. Finally, we use experimental data to estimate D for a few real swimmers. Interestingly, we find that D depends heavily on the kinematics of swimming, and, in certain cases, D can be significantly greater

  3. Finite-volume and partial quenching effects in the magnetic polarizability of the neutron

    Science.gov (United States)

    Hall, J. M. M.; Leinweber, D. B.; Young, R. D.

    2014-03-01

    There has been much progress in the experimental measurement of the electric and magnetic polarizabilities of the nucleon. Similarly, lattice QCD simulations have recently produced dynamical QCD results for the magnetic polarizability of the neutron approaching the chiral regime. In order to compare the lattice simulations with experiment, calculation of partial quenching and finite-volume effects is required prior to an extrapolation in quark mass to the physical point. These dependencies are described using chiral effective field theory. Corrections to the partial quenching effects associated with the sea-quark-loop electric charges are estimated by modeling corrections to the pion cloud. These are compared to the uncorrected lattice results. In addition, the behavior of the finite-volume corrections as a function of pion mass is explored. Box sizes of approximately 7 fm are required to achieve a result within 5% of the infinite-volume result at the physical pion mass. A variety of extrapolations are shown at different box sizes, providing a benchmark to guide future lattice QCD calculations of the magnetic polarizabilities. A relatively precise value for the physical magnetic polarizability of the neutron is presented, βn=1.93(11)stat(11)sys×10-4 fm3, which is in agreement with current experimental results.

  4. Partial molar volume of anionic polyelectrolytes in aqueous solution.

    Science.gov (United States)

    Salamanca, Constain; Contreras, Martín; Gamboa, Consuelo

    2007-05-15

    In this work the partial molar volumes (V) of different anionic polyelectrolytes and hydrophobically modified polyelectrolytes (PHM) were measured. Polymers like polymaleic acid-co-styrene, polymaleic acid-co-1-olefin, polymaleic acid-co-vinyl-2-pyrrolidone, and polyacrylic acid (abbreviated as MAS-n, PA-n-K2, AMVP, and PAA, respectively) were employed. These materials were investigated by density measurements in highly dilute aqueous solutions. The molar volume results allow us to discuss the effect of the carboxylic groups and the contributions from the comonomeric principal chain. The PAA presents the smaller V, while the largest V value was for AMVP. The V of PHM shows a linear relationship with the number of methylene groups in the lateral chain. It is found that the magnitude of the contribution per methylene group decreases as the hydrophobic character of the environment increases.

  5. Partial fourier and parallel MR image reconstruction with integrated gradient nonlinearity correction.

    Science.gov (United States)

    Tao, Shengzhen; Trzasko, Joshua D; Shu, Yunhong; Weavers, Paul T; Huston, John; Gray, Erin M; Bernstein, Matt A

    2016-06-01

    To describe how integrated gradient nonlinearity (GNL) correction can be used within noniterative partial Fourier (homodyne) and parallel (SENSE and GRAPPA) MR image reconstruction strategies, and demonstrate that performing GNL correction during, rather than after, these routines mitigates the image blurring and resolution loss caused by postreconstruction image domain based GNL correction. Starting from partial Fourier and parallel magnetic resonance imaging signal models that explicitly account for GNL, noniterative image reconstruction strategies for each accelerated acquisition technique are derived under the same core mathematical assumptions as their standard counterparts. A series of phantom and in vivo experiments on retrospectively undersampled data were performed to investigate the spatial resolution benefit of integrated GNL correction over conventional postreconstruction correction. Phantom and in vivo results demonstrate that the integrated GNL correction reduces the image blurring introduced by the conventional GNL correction, while still correcting GNL-induced coarse-scale geometrical distortion. Images generated from undersampled data using the proposed integrated GNL strategies offer superior depiction of fine image detail, for example, phantom resolution inserts and anatomical tissue boundaries. Noniterative partial Fourier and parallel imaging reconstruction methods with integrated GNL correction reduce the resolution loss that occurs during conventional postreconstruction GNL correction while preserving the computational efficiency of standard reconstruction techniques. Magn Reson Med 75:2534-2544, 2016. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.

  6. Finite volume for three-flavour Partially Quenched Chiral Perturbation Theory through NNLO in the meson sector

    Science.gov (United States)

    Bijnens, Johan; Rössler, Thomas

    2015-11-01

    We present a calculation of the finite volume corrections to meson masses and decay constants in three flavour Partially Quenched Chiral Perturbation Theory (PQChPT) through two-loop order in the chiral expansion for the flavour-charged (or off-diagonal) pseudoscalar mesons. The analytical results are obtained for three sea quark flavours with one, two or three different masses. We reproduce the known infinite volume results and the finite volume results in the unquenched case. The calculation has been performed using the supersymmetric formulation of PQChPT as well as with a quark flow technique.

  7. An improved approach to reduce partial volume errors in brain SPET

    International Nuclear Information System (INIS)

    Hatton, R.L.; Hatton, B.F.; Michael, G.; Barnden, L.; QUT, Brisbane, QLD; The Queen Elizabeth Hospital, Adelaide, SA

    1999-01-01

    Full text: Limitations in SPET resolution give rise to significant partial volume error (PVE) in small brain structures We have investigated a previously published method (Muller-Gartner et al., J Cereb Blood Flow Metab 1992;16: 650-658) to correct PVE in grey matter using MRI. An MRI is registered and segmented to obtain a grey matter tissue volume which is then smoothed to obtain resolution matched to the corresponding SPET. By dividing the original SPET with this correction map, structures can be corrected for PVE on a pixel-by-pixel basis. Since this approach is limited by space-invariant filtering, modification was made by estimating projections for the segmented MRI and reconstructing these using identical parameters to SPET. The methods were tested on simulated brain scans, reconstructed with the ordered subsets EM algorithm (8,16, 32, 64 equivalent EM iterations) The new method provided better recovery visually. For 32 EM iterations, recovery coefficients were calculated for grey matter regions. The effects of potential errors in the method were examined. Mean recovery was unchanged with one pixel registration error, the maximum error found in most registration programs. Errors in segmentation > 2 pixels results in loss of accuracy for small structures. The method promises to be useful for reducing PVE in brain SPET

  8. Effect of Inhomogeneity correction for lung volume model in TPS

    International Nuclear Information System (INIS)

    Chung, Se Young; Lee, Sang Rok; Kim, Young Bum; Kwon, Young Ho

    2004-01-01

    The phantom that includes high density materials such as steel was custom-made to fix lung and bone in order to evaluation inhomogeneity correction at the time of conducting radiation therapy to treat lung cancer. Using this, values resulting from the inhomogeneous correction algorithm are compared on the 2 and 3 dimensional radiation therapy planning systems. Moreover, change in dose calculation was evaluated according to inhomogeneous by comparing with the actual measurement. As for the image acquisition, inhomogeneous correction phantom(Pig's vertebra, steel(8.21 g/cm 3 ), cork(0.23 g/cm 3 )) that was custom-made and the CT(Volume zoom, Siemens, Germany) were used. As for the radiation therapy planning system, Marks Plan(2D) and XiO(CMS, USA, 3D) were used. To compare with the measurement value, linear accelerator(CL/1800, Varian, USA) and ion chamber were used. Image, obtained from the CT was used to obtain point dose and dose distribution from the region of interest (ROI) while on the radiation therapy planning device. After measurement was conducted under the same conditions, value on the treatment planning device and measured value were subjected to comparison and analysis. And difference between the resulting for the evaluation on the use (or non-use) of inhomogeneity correction algorithm, and diverse inhomogeneity correction algorithm that is included in the radiation therapy planning device was compared as well. As result of comparing the results of measurement value on the region of interest within the inhomogeneity correction phantom and the value that resulted from the homogeneous and inhomogeneous correction, gained from the therapy planning device, margin of error of the measurement value and inhomogeneous correction value at the location 1 of the lung showed 0.8% on 2D and 0.5% on 3D. Margin of error of the measurement value and inhomogeneous correction value at the location 1 of the steel showed 12% on 2D and 5% on 3D, however, it is possible to

  9. The unfolding effects on the protein hydration shell and partial molar volume: a computational study.

    Science.gov (United States)

    Del Galdo, Sara; Amadei, Andrea

    2016-10-12

    In this paper we apply the computational analysis recently proposed by our group to characterize the solvation properties of a native protein in aqueous solution, and to four model aqueous solutions of globular proteins in their unfolded states thus characterizing the protein unfolded state hydration shell and quantitatively evaluating the protein unfolded state partial molar volumes. Moreover, by using both the native and unfolded protein partial molar volumes, we obtain the corresponding variations (unfolding partial molar volumes) to be compared with the available experimental estimates. We also reconstruct the temperature and pressure dependence of the unfolding partial molar volume of Myoglobin dissecting the structural and hydration effects involved in the process.

  10. Finite volume for three-flavour Partially Quenched Chiral Perturbation Theory through NNLO in the meson sector

    Energy Technology Data Exchange (ETDEWEB)

    Bijnens, Johan; Rössler, Thomas [Department of Astronomy and Theoretical Physics, Lund University,Sölvegatan 14A, SE 223-62 Lund (Sweden)

    2015-11-16

    We present a calculation of the finite volume corrections to meson masses and decay constants in three flavour Partially Quenched Chiral Perturbation Theory (PQChPT) through two-loop order in the chiral expansion for the flavour-charged (or off-diagonal) pseudoscalar mesons. The analytical results are obtained for three sea quark flavours with one, two or three different masses. We reproduce the known infinite volume results and the finite volume results in the unquenched case. The calculation has been performed using the supersymmetric formulation of PQChPT as well as with a quark flow technique. Partial analytical results can be found in the appendices. Some examples of cases relevant to lattice QCD are studied numerically. Numerical programs for all results are available as part of the CHIRON package.

  11. Finite volume for three-flavour Partially Quenched Chiral Perturbation Theory through NNLO in the meson sector

    International Nuclear Information System (INIS)

    Bijnens, Johan; Rössler, Thomas

    2015-01-01

    We present a calculation of the finite volume corrections to meson masses and decay constants in three flavour Partially Quenched Chiral Perturbation Theory (PQChPT) through two-loop order in the chiral expansion for the flavour-charged (or off-diagonal) pseudoscalar mesons. The analytical results are obtained for three sea quark flavours with one, two or three different masses. We reproduce the known infinite volume results and the finite volume results in the unquenched case. The calculation has been performed using the supersymmetric formulation of PQChPT as well as with a quark flow technique. Partial analytical results can be found in the appendices. Some examples of cases relevant to lattice QCD are studied numerically. Numerical programs for all results are available as part of the CHIRON package.

  12. The partial molar volume of BeSO4 in aqueous solutions

    International Nuclear Information System (INIS)

    Kuschel, F.; Seidel, J.

    1981-01-01

    The density of aqueous solutions of BeSO 4 has been measured as a function of the mole fraction in the range of 0.02487 x 10 -2 to 6.3082 x 10 -2 . From the results obtained the molar volume and partial molar volume have been calculated and the limiting value of the partial molar volume for Be 2+ was extrapolated in accordance with the Debye-Hueckel law

  13. Partial molar volumes and partial molar adiabatic compressibilities of a short chain perfluorosurfactant: Sodium heptafluorobutyrate in aqueous solutions at different temperatures

    International Nuclear Information System (INIS)

    Blanco, Elena; Ruso, Juan M.; Prieto, Gerardo; Sarmiento, Felix

    2005-01-01

    Density and ultrasound measurements of sodium heptafluorobutyrate in aqueous solutions at T = (283.15, 288.15, 293.15, 298.15, 303.15, 308.15, 313.15, 318.15, and 323.15) K have been obtained. From these results partial molar volumes and isentropic partial molar adiabatic compressibilities were calculated. Deviations from the Debye-Hueckel limiting law provide evidence for limited association at lower concentrations. The change of the partial molar volume and isentropic partial molar adiabatic compressibility upon aggregation was calculated. Variations of the change of partial molar volumes and isentropic partial molar adiabatic compressibility upon aggregation are discussed in terms of temperature

  14. Partial molar volumes and partial molar adiabatic compressibilities of a short chain perfluorosurfactant: Sodium heptafluorobutyrate in aqueous solutions at different temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Blanco, Elena [Group of Biophysics and Interfaces, Department of Applied Physics, Faculty of Physics, University of Santiago de Compostela, E-15782 Santiago de Compostela (Spain); Ruso, Juan M. [Group of Biophysics and Interfaces, Department of Applied Physics, Faculty of Physics, University of Santiago de Compostela, E-15782 Santiago de Compostela (Spain)]. E-mail: faruso@usc.es; Prieto, Gerardo [Group of Biophysics and Interfaces, Department of Applied Physics, Faculty of Physics, University of Santiago de Compostela, E-15782 Santiago de Compostela (Spain); Sarmiento, Felix [Group of Biophysics and Interfaces, Department of Applied Physics, Faculty of Physics, University of Santiago de Compostela, E-15782 Santiago de Compostela (Spain)

    2005-12-15

    Density and ultrasound measurements of sodium heptafluorobutyrate in aqueous solutions at T = (283.15, 288.15, 293.15, 298.15, 303.15, 308.15, 313.15, 318.15, and 323.15) K have been obtained. From these results partial molar volumes and isentropic partial molar adiabatic compressibilities were calculated. Deviations from the Debye-Hueckel limiting law provide evidence for limited association at lower concentrations. The change of the partial molar volume and isentropic partial molar adiabatic compressibility upon aggregation was calculated. Variations of the change of partial molar volumes and isentropic partial molar adiabatic compressibility upon aggregation are discussed in terms of temperature.

  15. Parsing partial molar volumes of small molecules: a molecular dynamics study.

    Science.gov (United States)

    Patel, Nisha; Dubins, David N; Pomès, Régis; Chalikian, Tigran V

    2011-04-28

    We used molecular dynamics (MD) simulations in conjunction with the Kirkwood-Buff theory to compute the partial molar volumes for a number of small solutes of various chemical natures. We repeated our computations using modified pair potentials, first, in the absence of the Coulombic term and, second, in the absence of the Coulombic and the attractive Lennard-Jones terms. Comparison of our results with experimental data and the volumetric results of Monte Carlo simulation with hard sphere potentials and scaled particle theory-based computations led us to conclude that, for small solutes, the partial molar volume computed with the Lennard-Jones potential in the absence of the Coulombic term nearly coincides with the cavity volume. On the other hand, MD simulations carried out with the pair interaction potentials containing only the repulsive Lennard-Jones term produce unrealistically large partial molar volumes of solutes that are close to their excluded volumes. Our simulation results are in good agreement with the reported schemes for parsing partial molar volume data on small solutes. In particular, our determined interaction volumes() and the thickness of the thermal volume for individual compounds are in good agreement with empirical estimates. This work is the first computational study that supports and lends credence to the practical algorithms of parsing partial molar volume data that are currently in use for molecular interpretations of volumetric data.

  16. Partial molar volume of proteins studied by the three-dimensional reference interaction site model theory.

    Science.gov (United States)

    Imai, Takashi; Kovalenko, Andriy; Hirata, Fumio

    2005-04-14

    The three-dimensional reference interaction site model (3D-RISM) theory is applied to the analysis of hydration effects on the partial molar volume of proteins. For the native structure of some proteins, the partial molar volume is decomposed into geometric and hydration contributions using the 3D-RISM theory combined with the geometric volume calculation. The hydration contributions are correlated with the surface properties of the protein. The thermal volume, which is the volume of voids around the protein induced by the thermal fluctuation of water molecules, is directly proportional to the accessible surface area of the protein. The interaction volume, which is the contribution of electrostatic interactions between the protein and water molecules, is apparently governed by the charged atomic groups on the protein surface. The polar atomic groups do not make any contribution to the interaction volume. The volume differences between low- and high-pressure structures of lysozyme are also analyzed by the present method.

  17. Function spaces and partial differential equations 2 volume set

    CERN Document Server

    Taheri, Ali

    2015-01-01

    This is a book written primarily for graduate students and early researchers in the fields of Analysis and Partial Differential Equations (PDEs). Coverage of the material is essentially self-contained, extensive and novel with great attention to details and rigour.

  18. Function spaces and partial differential equations volume 2 : contemporary analysis

    CERN Document Server

    Taheri, Ali

    2015-01-01

    This is a book written primarily for graduate students and early researchers in the fields of Analysis and Partial Differential Equations (PDEs). Coverage of the material is essentially self-contained, extensive and novel with great attention to details and rigour.

  19. Partial molar volumes of hydrogen and deuterium in niobium, vanadium, and tantalum

    International Nuclear Information System (INIS)

    Peterson, D.T.; Herro, H.M.

    1983-01-01

    The partial molar volumes of hydrogen and deuterium were measured in vanadium, niobium, and tantalum by a differential pressure technique. One-half of an electrolytically charged sample plat was compressed between hardened steel blocks in a hydraulic press. The activity of hydrogen in the hig pressure region was raised and caused hydrogen to diffuse into the low pressure region. The partia molar volume was calculated from the ratio of the hydrogen concentrations in the high and low pressure regions of the sample. Small isotope effects were found in the partial molar volume. Hydrogen had the larger volume in niobium and tantalum, but the reverse was true in vanadium

  20. Partial and apparent molar volumes of aqueous solutions of the 1:1 type electrolytes

    International Nuclear Information System (INIS)

    Klugman, I.Yu.

    2002-01-01

    Formulas for calculating partial and apparent molar volumes of MX (M=Li-Cs; X = Cl-I) electrolyte aqueous solutions in a wide range of concentrations from 0 to 4 mol/kg with error not in excess of 0.05% are suggested. It is shown that the previously employed formulas for calculating partial molar volumes of electrolytes give false indications of mutual effect of ions and actually they are fit solely for very small concentrations [ru

  1. Partial volume effect (PVE) on the arterial input function (AIF) in T1-weighted perfusion imaging and limitations of the multiplicative rescaling approach

    DEFF Research Database (Denmark)

    Hansen, Adam Espe; Pedersen, Henrik; Rostrup, Egill

    2009-01-01

    The partial volume effect (PVE) on the arterial input function (AIF) remains a major obstacle to absolute quantification of cerebral blood flow (CBF) using MRI. This study evaluates the validity and performance of a commonly used multiplicative rescaling of the AIF to correct for the PVE. In a gr...

  2. On Neglecting Chemical Exchange Effects When Correcting in Vivo 31P MRS Data for Partial Saturation

    Science.gov (United States)

    Ouwerkerk, Ronald; Bottomley, Paul A.

    2001-02-01

    Signal acquisition in most MRS experiments requires a correction for partial saturation that is commonly based on a single exponential model for T1 that ignores effects of chemical exchange. We evaluated the errors in 31P MRS measurements introduced by this approximation in two-, three-, and four-site chemical exchange models under a range of flip-angles and pulse sequence repetition times (TR) that provide near-optimum signal-to-noise ratio (SNR). In two-site exchange, such as the creatine-kinase reaction involving phosphocreatine (PCr) and γ-ATP in human skeletal and cardiac muscle, errors in saturation factors were determined for the progressive saturation method and the dual-angle method of measuring T1. The analysis shows that these errors are negligible for the progressive saturation method if the observed T1 is derived from a three-parameter fit of the data. When T1 is measured with the dual-angle method, errors in saturation factors are less than 5% for all conceivable values of the chemical exchange rate and flip-angles that deliver useful SNR per unit time over the range T1/5 ≤ TR ≤ 2T1. Errors are also less than 5% for three- and four-site exchange when TR ≥ T1*/2, the so-called "intrinsic" T1's of the metabolites. The effect of changing metabolite concentrations and chemical exchange rates on observed T1's and saturation corrections was also examined with a three-site chemical exchange model involving ATP, PCr, and inorganic phosphate in skeletal muscle undergoing up to 95% PCr depletion. Although the observed T1's were dependent on metabolite concentrations, errors in saturation corrections for TR = 2 s could be kept within 5% for all exchanging metabolites using a simple interpolation of two dual-angle T1 measurements performed at the start and end of the experiment. Thus, the single-exponential model appears to be reasonably accurate for correcting 31P MRS data for partial saturation in the presence of chemical exchange. Even in systems where

  3. Evaluation of the reconstruction method and effect of partial volume in brain scintiscanning

    International Nuclear Information System (INIS)

    Pinheiro, Monica Araujo

    2016-01-01

    Alzheimer's disease is a neurodegenerative disorder, on which occurs a progressive and irreversible destruction of neurons. According to the World Health Organization (WHO) 35.6 million people are living with dementia, being recommended that governments prioritize early diagnosis techniques. Laboratory and psychological tests for cognitive assessment are conducted and further complemented by neurological imaging from nuclear medicine exams in order to establish an accurate diagnosis. The image quality evaluation and reconstruction process effects are important tools in clinical routine. In the present work, these quality parameters were studied, and the effects of partial volume (PVE) for lesions of different sizes and geometries that are attributed to the limited resolution of the equipment. In dementia diagnosis, this effect can be confused with intake losses due to cerebral cortex atrophy. The evaluation was conducted by two phantoms of different shapes as suggested by (a) American College of Radiology (ACR) and (b) National Electrical Manufacturers Association (NEMA) for Contrast, Contrast-to-Noise Ratio (CNR) and Recovery Coefficient (RC) calculation versus lesions shape and size. Technetium-99m radionuclide was used in a local brain scintigraphy protocol, for proportions lesion to background of 2:1, 4:1, 6:1, 8:1 and 10:1. Fourteen reconstruction methods were used for each concentration applying different filters and algorithms. Before the analysis of all image properties, the conclusion is that the predominant effect is the partial volume, leading to errors of measurement of more than 80%. Furthermore, it was demonstrate that the most effective method of reconstruction is FBP with Metz filter, providing better contrast and contrast to noise ratio results. In addition, this method shows the best Recovery Coefficients correction for each lesion. The ACR phantom showed the best results assigned to a more precise reconstruction of a cylinder, which does not

  4. FMDP Reactor Alternative Summary Report: Volume 3 - partially complete LWR alternative

    International Nuclear Information System (INIS)

    Greene, S.R.; Fisher, S.E.; Bevard, B.B.

    1996-09-01

    The Department of Energy Office of Fissile Materials Disposition (DOE/MD) initiated a detailed analysis activity to evaluate each of ten plutonium disposition alternatives that survived an initial screening process. This document, Volume 3 of a four volume report summarizes the results of these analyses for the partially complete LWR (PCLWR) reactor based plutonium disposition alternative

  5. FMDP Reactor Alternative Summary Report: Volume 3 - partially complete LWR alternative

    Energy Technology Data Exchange (ETDEWEB)

    Greene, S.R.; Fisher, S.E.; Bevard, B.B. [and others

    1996-09-01

    The Department of Energy Office of Fissile Materials Disposition (DOE/MD) initiated a detailed analysis activity to evaluate each of ten plutonium disposition alternatives that survived an initial screening process. This document, Volume 3 of a four volume report summarizes the results of these analyses for the partially complete LWR (PCLWR) reactor based plutonium disposition alternative.

  6. Note: Nonpolar solute partial molar volume response to attractive interactions with water.

    Science.gov (United States)

    Williams, Steven M; Ashbaugh, Henry S

    2014-01-07

    The impact of attractive interactions on the partial molar volumes of methane-like solutes in water is characterized using molecular simulations. Attractions account for a significant 20% volume drop between a repulsive Weeks-Chandler-Andersen and full Lennard-Jones description of methane interactions. The response of the volume to interaction perturbations is characterized by linear fits to our simulations and a rigorous statistical thermodynamic expression for the derivative of the volume to increasing attractions. While a weak non-linear response is observed, an average effective slope accurately captures the volume decrease. This response, however, is anticipated to become more non-linear with increasing solute size.

  7. Note: Nonpolar solute partial molar volume response to attractive interactions with water

    Energy Technology Data Exchange (ETDEWEB)

    Williams, Steven M.; Ashbaugh, Henry S., E-mail: hanka@tulane.edu [Department of Chemical and Biomolecular Engineering, Tulane University, New Orleans, Louisiana 70118 (United States)

    2014-01-07

    The impact of attractive interactions on the partial molar volumes of methane-like solutes in water is characterized using molecular simulations. Attractions account for a significant 20% volume drop between a repulsive Weeks-Chandler-Andersen and full Lennard-Jones description of methane interactions. The response of the volume to interaction perturbations is characterized by linear fits to our simulations and a rigorous statistical thermodynamic expression for the derivative of the volume to increasing attractions. While a weak non-linear response is observed, an average effective slope accurately captures the volume decrease. This response, however, is anticipated to become more non-linear with increasing solute size.

  8. The partial volume effect in the quantification of 1H magnetic resonance spectroscopy in Alzheimer's disease and aging.

    Science.gov (United States)

    Mato Abad, Virginia; Quirós, Alicia; García-Álvarez, Roberto; Loureiro, Javier Pereira; Alvarez-Linera, Juan; Frank, Ana; Hernández-Tamames, Juan Antonio

    2014-01-01

    1H-MRS variability increases due to normal aging and also as a result of atrophy in grey and white matter caused by neurodegeneration. In this work, an automatic process was developed to integrate data from spectra and high-resolution anatomical images to quantify metabolites, taking into account tissue partial volumes within the voxel of interest avoiding additional spectra acquisitions required for partial volume correction. To evaluate this method, we use a cohort of 135 subjects (47 male and 88 female, aged between 57 and 99 years) classified into 4 groups: 38 healthy participants, 20 amnesic mild cognitive impairment patients, 22 multi-domain mild cognitive impairment patients, and 55 Alzheimer's disease patients. Our findings suggest that knowing the voxel composition of white and grey matter and cerebrospinal fluid is necessary to avoid partial volume variations in a single-voxel study and to decrease part of the variability found in metabolites quantification, particularly in those studies involving elder patients and neurodegenerative diseases. The proposed method facilitates the use of 1H-MRS techniques in statistical studies in Alzheimer's disease, because it provides more accurate quantitative measurements, reduces the inter-subject variability, and improves statistical results when performing group comparisons.

  9. Volume correction in the aging hand: role of dermal fillers

    Directory of Open Access Journals (Sweden)

    Rivkin AZ

    2016-08-01

    Full Text Available Alexander Z Rivkin David Geffen/UCLA School of Medicine Los Angeles, CA, USA Abstract: The hands, just like the face, are highly visible parts of the body. They age at a similar rate and demonstrate comparable changes with time, sun damage, and smoking. Loss of volume in the hands exposes underlying tendons, veins, and bony prominences. Rejuvenation of the hands with dermal fillers is a procedure with high patient satisfaction and relatively low risk for complications. This study will review relevant anatomy, injection technique, clinical safety, and efficacy of dermal filler volumization of the aging hand. Keywords: dermal fillers, hands, volumization, hyaluronic acid, calcium hydroxylapatite

  10. Vector velocity volume flow estimation: Sources of error and corrections applied for arteriovenous fistulas

    DEFF Research Database (Denmark)

    Jensen, Jonas; Olesen, Jacob Bjerring; Stuart, Matthias Bo

    2016-01-01

    radius. The error sources were also studied in vivo under realistic clinical conditions, and the theoretical results were applied for correcting the volume flow errors. Twenty dialysis patients with arteriovenous fistulas were scanned to obtain vector flow maps of fistulas. When fitting an ellipsis......A method for vector velocity volume flow estimation is presented, along with an investigation of its sources of error and correction of actual volume flow measurements. Volume flow errors are quantified theoretically by numerical modeling, through flow phantom measurements, and studied in vivo...

  11. Partial molar volumes of hydrogen and deuterium in niobium and vanadium

    International Nuclear Information System (INIS)

    Herro, H.M.

    1979-01-01

    Lattice dilation studies and direct pressure experiments gave comparable values for the partial molar volumes of hydrogen and deuterium in niobium and vanadium. Small isotope effects in the partial molar volume of hydrogen were measured in both metals by the differential isotope method. Hydrogen had a larger partial molar volume than deuterium in niobium, but the reverse was true in vanadium. The isotope effect measured in niobium can be represented as being due to the larger amplitude of vibration of the hydrogen atom than the deuterium atom in the metal lattice. Since hydrogen has a larger mean displacement from the equilibrium position than does deuterium, the average force hydrogen exerts on the metal atoms is greater than the force deuterium exerts. The isotope effect in vanadium is likely a result of anharmonic effects in the lattice and local vibrational modes

  12. Determination of Partial Molar Volumes of EPA and DHA Ethyl Esters in Supercritical Carbon Dioxide

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The use of supercritical-fluid chromatography for determining partial molar volumes of ethyl esters of cis-5,8,11,14,17-eicosapentaenoic acid (EPA) and cis -4,7,10,13,16,19- docosa-hexaenoic acid (DHA) in supercritical carbon dioxide is presented and discussed. Partial molar volumes of EPA and DHA esters are obtained from the variation of the retention properties with the density of mobile phase at 313.15 K, 323.15 K, 333.15 K and in the pressure range from 9 MPa to 21 MPa.

  13. Effect of Molecular Size of Solutes on Their Partial Molar Volumes in Supercritical n-Pentane

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The densities of n-pentane, methane-n-pentane, propane-n-pentane, n-heptane-n-pentane, and n-decane-n-pentane binary mixtures were determined at 476.5K in the pressure range from 2 to 5 MPa. The partial molar volumes of the solutes in n-pentane were calculated using the density data. It was found that the partial molar volumes of methane and propane are positive , while those of n-heptane and n-decane are negative.

  14. Deptermination of Partial Molar Volumes of EPA and DHA Ethyl Esters in Supercritical Carbon Dioxide

    Institute of Scientific and Technical Information of China (English)

    MeiHUANG; XianDaWANG; 等

    2002-01-01

    The use of supercritical-fluid shromatogrphy for determining partial molar volumes of ethyl esters of cis-5,8,11,14,17-eicosapentaenoic acid (EPA) and cis-4,7,10,13,16,19-docosa-hexaenoic acid(DHA) in supercritical carbon dioxide is presented and discussed. Partial molar volumes of EPA and DHA esters are obtained from the variation of the retention properties with the density of mobile phase at 313.15K,323.15K,333.15K and in the pressure range from 9 MPa to 21 MPa.

  15. Analysis of Partial Volume Effects on Arterial Input Functions Using Gradient Echo: A Simulation Study

    DEFF Research Database (Denmark)

    Kjølby, Birgitte Fuglsang; Mikkelsen, Irene Klærke; Pedersen, Michael

    2009-01-01

    of an AIF voxel including the relaxation properties of blood and tissue. Artery orientations parallel and perpendicular to the main magnetic field were investigated and AIF voxels were modeled to either include or be situated close to a large artery. The impact of partial volume effects on quantitative...... perfusion metrics was investigated for the gradient echo pulse sequence at 1.5 T and 3.0 T. It is shown that the tissue contribution broadens and introduces fluctuations in the AIF. Furthermore, partial volume effects bias perfusion metrics in a nonlinear fashion, compromising quantitative perfusion...

  16. Partial volume and aliasing artefacts in helical cone-beam CT

    International Nuclear Information System (INIS)

    Zou Yu; Sidky, Emil Y; Pan, Xiaochuan

    2004-01-01

    A generalization of the quasi-exact algorithms of Kudo et al (2000 IEEE Trans. Med. Imaging 19 902-21) is developed that allows for data acquisition in a 'practical' frame for clinical diagnostic helical, cone-beam computed tomography (CT). The algorithm is investigated using data that model nonlinear partial volume averaging. This investigation leads to an understanding of aliasing artefacts in helical, cone-beam CT image reconstruction. An ad hoc scheme is proposed to mitigate artefacts due to the nonlinear partial volume and aliasing artefacts

  17. Quantitative analysis of CT brain images: a statistical model incorporating partial volume and beam hardening effects

    International Nuclear Information System (INIS)

    McLoughlin, R.F.; Ryan, M.V.; Heuston, P.M.; McCoy, C.T.; Masterson, J.B.

    1992-01-01

    The purpose of this study was to construct and evaluate a statistical model for the quantitative analysis of computed tomographic brain images. Data were derived from standard sections in 34 normal studies. A model representing the intercranial pure tissue and partial volume areas, with allowance for beam hardening, was developed. The average percentage error in estimation of areas, derived from phantom tests using the model, was 28.47%. We conclude that our model is not sufficiently accurate to be of clinical use, even though allowance was made for partial volume and beam hardening effects. (author)

  18. Study of the seroma volume changes in the patients who underwent Accelerated Partial Breast Irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dae Ho; Son, Sang Jun; Mun, Jun Ki; Seo, Seok Jin; Lee, Je Hee [Dept. of Radiation Oncology, Seoul National University Hospital, Seoul (Korea, Republic of)

    2016-06-15

    By analyzing seroma volume changes in the patients who underwent Partial breast radiation therapy after breast conserving surgery, we try to contribute to the improvement of radiotherapy effect. Enrolled 20 patients who underwent partial breast radiation therapy by ViewRay MRIdian System were subject. After seeking for the size of the removed sample in the patients during surgery and obtained seroma volume changes on a weekly basis. On the Basis of acquired volume, it was compared with age, term from start of the first treatment after surgery, BMI (body mass index) and the extracted sample size during surgery. And using the ViewRay MRIdian RTP System, the figure was analyzed by PTV(=seroma volume + margin) to obtain a specific volume of the Partial breast radiation therapy. The changes of seroma volume from MR simulation to the first treatment (a week) is 0~5% in 8, 5~10% in 3, 10 to 15% in 2, and 20% or more in 5 people. Two patients(A, B patient) among subjects showed the biggest change. The A patient's 100% of the prescribed dose volume is 213.08 cc, PTV is 181.93 cc, seroma volume is 15.3 cc in initial plan. However, while seroma volume decreased 65.36% to 5.3 cc, 100% of the prescribed dose volume was reduced to 3.4% to 102.43 cc and PTV also did 43.6% to 102.54 cc. In the case of the B patient, seroma volume decreased 42.57% from 20.2 cc to 11.6 cc. Because of that, 100% of the prescribed dose volume decreased 8.1% and PTV also did to 40%. As the period between the first therapy and surgery is shorter, the patient is elder and the size of sample is smaller than 100 cc, the change grow bigger. It is desirable to establish an adaptive plan according to each patient's changes of seroma volume through continuous observation. Because partial breast patients is more sensitive than WBRT patients about dose conformity in accordance with the volume change.

  19. Study of the seroma volume changes in the patients who underwent Accelerated Partial Breast Irradiation

    International Nuclear Information System (INIS)

    Kim, Dae Ho; Son, Sang Jun; Mun, Jun Ki; Seo, Seok Jin; Lee, Je Hee

    2016-01-01

    By analyzing seroma volume changes in the patients who underwent Partial breast radiation therapy after breast conserving surgery, we try to contribute to the improvement of radiotherapy effect. Enrolled 20 patients who underwent partial breast radiation therapy by ViewRay MRIdian System were subject. After seeking for the size of the removed sample in the patients during surgery and obtained seroma volume changes on a weekly basis. On the Basis of acquired volume, it was compared with age, term from start of the first treatment after surgery, BMI (body mass index) and the extracted sample size during surgery. And using the ViewRay MRIdian RTP System, the figure was analyzed by PTV(=seroma volume + margin) to obtain a specific volume of the Partial breast radiation therapy. The changes of seroma volume from MR simulation to the first treatment (a week) is 0~5% in 8, 5~10% in 3, 10 to 15% in 2, and 20% or more in 5 people. Two patients(A, B patient) among subjects showed the biggest change. The A patient's 100% of the prescribed dose volume is 213.08 cc, PTV is 181.93 cc, seroma volume is 15.3 cc in initial plan. However, while seroma volume decreased 65.36% to 5.3 cc, 100% of the prescribed dose volume was reduced to 3.4% to 102.43 cc and PTV also did 43.6% to 102.54 cc. In the case of the B patient, seroma volume decreased 42.57% from 20.2 cc to 11.6 cc. Because of that, 100% of the prescribed dose volume decreased 8.1% and PTV also did to 40%. As the period between the first therapy and surgery is shorter, the patient is elder and the size of sample is smaller than 100 cc, the change grow bigger. It is desirable to establish an adaptive plan according to each patient's changes of seroma volume through continuous observation. Because partial breast patients is more sensitive than WBRT patients about dose conformity in accordance with the volume change

  20. Partial Tmem106b reduction does not correct abnormalities due to progranulin haploinsufficiency.

    Science.gov (United States)

    Arrant, Andrew E; Nicholson, Alexandra M; Zhou, Xiaolai; Rademakers, Rosa; Roberson, Erik D

    2018-06-22

    Loss of function mutations in progranulin (GRN) are a major cause of frontotemporal dementia (FTD). Progranulin is a secreted glycoprotein that localizes to lysosomes and is critical for proper lysosomal function. Heterozygous GRN mutation carriers develop FTD with TDP-43 pathology and exhibit signs of lysosomal dysfunction in the brain, with increased levels of lysosomal proteins and lipofuscin accumulation. Homozygous GRN mutation carriers develop neuronal ceroid lipofuscinosis (NCL), an earlier-onset lysosomal storage disorder caused by severe lysosomal dysfunction. Multiple genome-wide association studies have shown that risk of FTD in GRN mutation carriers is modified by polymorphisms in TMEM106B, which encodes a lysosomal membrane protein. Risk alleles of TMEM106B may increase TMEM106B levels through a variety of mechanisms. Brains from FTD patients with GRN mutations exhibit increased TMEM106B expression, and protective TMEM106B polymorphisms are associated with decreased TMEM106B expression. Together, these data raise the possibility that reduction of TMEM106B levels may protect against the pathogenic effects of progranulin haploinsufficiency. We crossed Tmem106b +/- mice with Grn +/- mice, which model the progranulin haploinsufficiency of GRN mutation carriers and develop age-dependent social deficits and lysosomal abnormalities in the brain. We tested whether partial Tmem106b reduction could normalize the social deficits and lysosomal abnormalities of Grn +/- mice. Partial reduction of Tmem106b levels did not correct the social deficits of Grn +/- mice. Tmem106b reduction also failed to normalize most lysosomal abnormalities of Grn +/- mice, except for β-glucuronidase activity, which was suppressed by Tmem106b reduction and increased by progranulin insufficiency. These data do not support the hypothesis that Tmem106b reduction protects against the pathogenic effects of progranulin haploinsufficiency, but do show that Tmem106b reduction normalizes some

  1. Isotropic non-white matter partial volume effects in constrained spherical deconvolution

    Directory of Open Access Journals (Sweden)

    Timo eRoine

    2014-03-01

    Full Text Available Diffusion-weighted (DW magnetic resonance imaging (MRI is a noninvasive imaging method, which can be used to investigate neural tracts in the white matter (WM of the brain. Significant partial volume effects (PVE are present in the DW signal due to relatively large voxel sizes. These PVEs can be caused by both non-WM tissue, such as gray matter (GM and cerebrospinal fluid (CSF, and by multiple nonparallel WM fiber populations. High angular resolution diffusion imaging (HARDI methods have been developed to correctly characterize complex WM fiber configurations, but to date, many of the HARDI methods do not account for non-WM PVEs. In this work, we investigated the isotropic PVEs caused by non-WM tissue in WM voxels on fiber orientations extracted with constrained spherical deconvolution (CSD. Experiments were performed on simulated and real DW-MRI data. In particular, simulations were performed to demonstrate the effects of varying the diffusion weightings, signal-to-noise ratios (SNR, fiber configurations, and tissue fractions.Our results show that the presence of non-WM tissue signal causes a decrease in the precision of the detected fiber orientations and an increase in the detection of false peaks in CSD. We estimated 35-50 % of WM voxels to be affected by non-WM PVEs. For HARDI sequences, which typically have a relatively high degree of diffusion weighting, these adverse effects are most pronounced in voxels with GM PVEs. The non-WM PVEs become severe with 50 % GM volume for maximum spherical harmonics orders of 8 and below, and already with 25 % GM volume for higher orders. In addition, a low diffusion weighting or SNR increases the effects. The non-WM PVEs may cause problems in connectomics, where reliable fiber tracking at the WM-GM interface is especially important. We suggest acquiring data with high diffusion-weighting 2500-3000 s/mm2, reasonable SNR (~30 and using lower SH orders in GM contaminated regions to minimize the non-WM PVEs

  2. Isotropic non-white matter partial volume effects in constrained spherical deconvolution.

    Science.gov (United States)

    Roine, Timo; Jeurissen, Ben; Perrone, Daniele; Aelterman, Jan; Leemans, Alexander; Philips, Wilfried; Sijbers, Jan

    2014-01-01

    Diffusion-weighted (DW) magnetic resonance imaging (MRI) is a non-invasive imaging method, which can be used to investigate neural tracts in the white matter (WM) of the brain. Significant partial volume effects (PVEs) are present in the DW signal due to relatively large voxel sizes. These PVEs can be caused by both non-WM tissue, such as gray matter (GM) and cerebrospinal fluid (CSF), and by multiple non-parallel WM fiber populations. High angular resolution diffusion imaging (HARDI) methods have been developed to correctly characterize complex WM fiber configurations, but to date, many of the HARDI methods do not account for non-WM PVEs. In this work, we investigated the isotropic PVEs caused by non-WM tissue in WM voxels on fiber orientations extracted with constrained spherical deconvolution (CSD). Experiments were performed on simulated and real DW-MRI data. In particular, simulations were performed to demonstrate the effects of varying the diffusion weightings, signal-to-noise ratios (SNRs), fiber configurations, and tissue fractions. Our results show that the presence of non-WM tissue signal causes a decrease in the precision of the detected fiber orientations and an increase in the detection of false peaks in CSD. We estimated 35-50% of WM voxels to be affected by non-WM PVEs. For HARDI sequences, which typically have a relatively high degree of diffusion weighting, these adverse effects are most pronounced in voxels with GM PVEs. The non-WM PVEs become severe with 50% GM volume for maximum spherical harmonics orders of 8 and below, and already with 25% GM volume for higher orders. In addition, a low diffusion weighting or SNR increases the effects. The non-WM PVEs may cause problems in connectomics, where reliable fiber tracking at the WM-GM interface is especially important. We suggest acquiring data with high diffusion-weighting 2500-3000 s/mm(2), reasonable SNR (~30) and using lower SH orders in GM contaminated regions to minimize the non-WM PVEs in CSD.

  3. Partial molar volumes of proteins: amino acid side-chain contributions derived from the partial molar volumes of some tripeptides over the temperature range 10-90 degrees C.

    Science.gov (United States)

    Häckel, M; Hinz, H J; Hedwig, G R

    1999-11-15

    The partial molar volumes of tripeptides of sequence glycyl-X-glycine, where X is one of the amino acids alanine, leucine, threonine, glutamine, phenylalanine, histidine, cysteine, proline, glutamic acid, and arginine, have been determined in aqueous solution over the temperature range 10-90 degrees C using differential scanning densitometry . These data, together with those reported previously, have been used to derive the partial molar volumes of the side-chains of all 20 amino acids. The side-chain volumes are critically compared with literature values derived using partial molar volumes for alternative model compounds. The new amino acid side-chain volumes, along with that for the backbone glycyl group, were used to calculate the partial specific volumes of several proteins in aqueous solution. The results obtained are compared with those observed experimentally. The new side-chain volumes have also been used to re-determine residue volume changes upon protein folding.

  4. Probabilistic Characterization of Partial Volume Effects in Imaging of Rectangular Objects

    Energy Technology Data Exchange (ETDEWEB)

    Bulaevskaya, V. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-05-06

    In imaging, a partial volume effect refers to the problem that arises when the system resolution is low relative to the size of the object being imaged [1, 2]. In this setting, it is likely that most voxels occupied by the object are only partially covered, and that the fraction covered in each voxel is low. This makes the problem of object detection and image segmentation very difficult because the algorithms designed for these purposes rely on pixel summary statistics. If the area covered by the object is very low in relatively many of the total number of the voxels the object occupies, these summary statistics may not reach the thresholds required to detect this object. It is thus important to understand the extent of partial volume effect for a given object size and resolution. This technical report focuses on rectangular objects and derives the probability distributions for three quantities for such objects: 1) the number of fully covered voxels, 2) the number of partially covered voxels, and 3) the fractions of the total volume covered in the partially covered voxels. The derivations are first shown for 2-D settings and are then extended to 3-D settings.

  5. A study of partial molar volumes of citric acid and tartaric acid

    Indian Academy of Sciences (India)

    Partial molar volumes of citric acid and tartaric acid have been determined in water and binary aqueous mixtures of ethanol (5, 10, 15, 20 and 25% by weight of ethanol) at different temperatures and acid concentrations from the solution density measurements. The data have been evaluated by using Masson equation and ...

  6. Anomaly-free perturbations with inverse-volume and holonomy corrections in loop quantum cosmology

    International Nuclear Information System (INIS)

    Cailleteau, Thomas; Linsefors, Linda; Barrau, Aurelien

    2014-01-01

    This paper addresses the issue of the closure of the algebra of constraints for generic (cosmological) perturbations when taking into account simultaneously the two main corrections of effective loop quantum cosmology, namely the holonomy and the inverse-volume terms. Previous works on either the holonomy or the inverse-volume case are reviewed and generalized. In the inverse-volume case, we point out new possibilities. An anomaly-free solution including both corrections is found for perturbations, and the corresponding equations of motion are derived. (paper)

  7. Intrinsic alterations in the partial molar volume on the protein denaturation: surficial Kirkwood-Buff approach.

    Science.gov (United States)

    Yu, Isseki; Takayanagi, Masayoshi; Nagaoka, Masataka

    2009-03-19

    The partial molar volume (PMV) of the protein chymotrypsin inhibitor 2 (CI2) was calculated by all-atom MD simulation. Denatured CI2 showed almost the same average PMV value as that of native CI2. This is consistent with the phenomenological question of the protein volume paradox. Furthermore, using the surficial Kirkwood-Buff approach, spatial distributions of PMV were analyzed as a function of the distance from the CI2 surface. The profiles of the new R-dependent PMV indicate that, in denatured CI2, the reduction in the solvent electrostatic interaction volume is canceled out mainly by an increment in thermal volume in the vicinity of its surface. In addition, the PMV of the denatured CI2 was found to increase in the region in which the number density of water atoms is minimum. These results provide a direct and detailed picture of the mechanism of the protein volume paradox suggested by Chalikian et al.

  8. Standard partial molar volumes of some electrolytes in ethylene carbonate based mixtures

    International Nuclear Information System (INIS)

    Zhao, Yang; Wang, Jianji.; Lu, Hui; Lin, Ruisen

    2004-01-01

    Apparent molar volumes V 2,phi and standard partial molar volumes V 2,phi 0 of LiClO 4 , LiBr and three symmetrical tetraalkylammonium bromides R 4 NBr (R=ethyl, propyl, butyl) have been determined at 298.15 K from precise density measurements in solvent mixtures of ethylene carbonate with tetrahydrofuran (THF), acetonitrile (AN), ethyl acetate (EA) and dimethoxyethane (DME). It is shown that the V 2,phi 0 values of LiClO 4 and LiBr are dependent strongly on the nature of the solvents, whereas the contribution of CH 2 group to the partial molar volume of the tetraalkylammonium salts has nothing to do with the nature of the solvents and the composition of the solvent mixtures. This provided a helpful evidence for the unsolvation of large tetraalkylammonium cations in organic solvents. The results have been discussed from ion-solvent interactions and the dielectric effect of the solvents

  9. Ribosomal Stalk Protein Silencing Partially Corrects the ΔF508-CFTR Functional Expression Defect.

    Directory of Open Access Journals (Sweden)

    Guido Veit

    2016-05-01

    Full Text Available The most common cystic fibrosis (CF causing mutation, deletion of phenylalanine 508 (ΔF508 or Phe508del, results in functional expression defect of the CF transmembrane conductance regulator (CFTR at the apical plasma membrane (PM of secretory epithelia, which is attributed to the degradation of the misfolded channel at the endoplasmic reticulum (ER. Deletion of phenylalanine 670 (ΔF670 in the yeast oligomycin resistance 1 gene (YOR1, an ABC transporter of Saccharomyces cerevisiae phenocopies the ΔF508-CFTR folding and trafficking defects. Genome-wide phenotypic (phenomic analysis of the Yor1-ΔF670 biogenesis identified several modifier genes of mRNA processing and translation, which conferred oligomycin resistance to yeast. Silencing of orthologues of these candidate genes enhanced the ΔF508-CFTR functional expression at the apical PM in human CF bronchial epithelia. Although knockdown of RPL12, a component of the ribosomal stalk, attenuated the translational elongation rate, it increased the folding efficiency as well as the conformational stability of the ΔF508-CFTR, manifesting in 3-fold augmented PM density and function of the mutant. Combination of RPL12 knockdown with the corrector drug, VX-809 (lumacaftor restored the mutant function to ~50% of the wild-type channel in primary CFTRΔF508/ΔF508 human bronchial epithelia. These results and the observation that silencing of other ribosomal stalk proteins partially rescue the loss-of-function phenotype of ΔF508-CFTR suggest that the ribosomal stalk modulates the folding efficiency of the mutant and is a potential therapeutic target for correction of the ΔF508-CFTR folding defect.

  10. Correction

    DEFF Research Database (Denmark)

    Pinkevych, Mykola; Cromer, Deborah; Tolstrup, Martin

    2016-01-01

    [This corrects the article DOI: 10.1371/journal.ppat.1005000.][This corrects the article DOI: 10.1371/journal.ppat.1005740.][This corrects the article DOI: 10.1371/journal.ppat.1005679.].......[This corrects the article DOI: 10.1371/journal.ppat.1005000.][This corrects the article DOI: 10.1371/journal.ppat.1005740.][This corrects the article DOI: 10.1371/journal.ppat.1005679.]....

  11. Localization of Epileptogenic Zones using Partical Volume Corrected FDG Uptake on FDG PET and Voxel Based Morphometry on MRI

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Won Jun; Lee, Ho Young; Lee, Jae Sung; Lee, Dong Soo; Lee, Sang Kun; Chung, June Key; Lee, Myung Chul [College of Medicine, Univ. of Seoul National, Seoul (Korea, Republic of)

    2003-07-01

    Partial volume corrected (PVC) FDG uptake yields information about regional metabolic level void of volume change, and voxel based morphometry (VBM) yields objective information regarding gray matter concentration. We investigated the roles of PVC PET and VBM to localize epileptogenic zones in medial temporal lobe epilepsy (mTLE) and non-lesional neocortical epilepsy. As a control group for PVC, 40 normal volunteers without history of neurologic or psychiatric diseases underwent FDG PET and MRI. Seventeen mTLE patients (M: F=7: 10, age=309 y) and nine neocortical epilepsy patients (M: F=6: 3, age=246, lateral temporal: 5, frontal: 3, occipital: 1) confirmed by surgery or epilepsy board meeting were enrolled. Standard VBM analysis was performed using individual MRI images compared with those of age-matched controls. For PVC, FDG PET was co-registered with its own MRI. PVC PET was obtained by dividing spillover-corrected PET by smoothed gray matter image pixel by pixel. SPAM was applied as a mask of volume of interest (VOI) to calculate gyral FDG uptake on PVC-FDG PET. Hippocampus, amygdala, superior, middle, inferior temporal gyrus and parahippocampal gyrus were the gyral SPAM VOIs in mTLE. Globally normalized PVC-FDG counts were compared with those of age-matched controls in mTLE and neocortical epilepsy patients. In mTlE, PVC-FDG PET correctly localized epileptogenic zones with the accuracy of 76% (13/17) in hippocampus and 82% (14/17) in any of six regions. VBM correctly localized 59% (10/17) in mTLE. In neocortical epilepsy, PVC-FDG PET localized epileptogenic zones in 44%, and VBM in 33%, Using VBM and PVC-FDG PET altogether, epileptogenic zones were localized in 66% (6/9). In mTLE, gyral PVC FDG uptake of temporal lobes was useful in localizing epileptogenic zones by demonstrating partial volume-void FDG concentration. In non-lesional cryptogenic neocortical epilepsy, combination of PVC-FDG PET and VBM is recommended to localize epileptogenic zones.

  12. Baseline correction combined partial least squares algorithm and its application in on-line Fourier transform infrared quantitative analysis.

    Science.gov (United States)

    Peng, Jiangtao; Peng, Silong; Xie, Qiong; Wei, Jiping

    2011-04-01

    In order to eliminate the lower order polynomial interferences, a new quantitative calibration algorithm "Baseline Correction Combined Partial Least Squares (BCC-PLS)", which combines baseline correction and conventional PLS, is proposed. By embedding baseline correction constraints into PLS weights selection, the proposed calibration algorithm overcomes the uncertainty in baseline correction and can meet the requirement of on-line attenuated total reflectance Fourier transform infrared (ATR-FTIR) quantitative analysis. The effectiveness of the algorithm is evaluated by the analysis of glucose and marzipan ATR-FTIR spectra. BCC-PLS algorithm shows improved prediction performance over PLS. The root mean square error of cross-validation (RMSECV) on marzipan spectra for the prediction of the moisture is found to be 0.53%, w/w (range 7-19%). The sugar content is predicted with a RMSECV of 2.04%, w/w (range 33-68%). Copyright © 2011 Elsevier B.V. All rights reserved.

  13. A spreadsheet to determine the volume ratio for target and breast in partial breast irradiation

    International Nuclear Information System (INIS)

    Kron, T.; Willis, D.; Miller, J.; Hubbard, P.; Oliver, M.; Chua, B.

    2009-01-01

    Full text: The technical feasibility of Partial Breast Irradiation (PBI) using external beam radiotherapy depends on the ratio between the evaluation planning target volume (PTV e val) and the whole breast volume (PBI volume ratio = PVR). We aimed to develop a simple method to determine PVR using measurements performed at the time of the planning CT scan. A PVR calculation tool was developed using a Microsoft Excel spreadsheet to determine the PTV from three orthogonal dimensions of the seroma cavity and a given margin on the CT scans. The breast volume is estimated from the separation and breast height in five equally spaced CT slices. The PTV e val and whole breast volume were determined for 29 patients from two centres using the spreadsheet calculation tool and compared to volumes delineated on computerised treatment planning systems. Both the PTV e val and whole breast volumes were underestimated by approximately 25% using the spreadsheet. The resulting PVRs were 1.05 +/- 0.35 (mean +/- 1 S D) times larger than the ones determined from planning. Estimations of the PVR using the calculation tool were achievable in around 5 minutes at the time of CT scanning and allow a prompt decision on the suitability of the patients for PBI.

  14. The (water + acetonitrile) mixture revisited: A new approach for calculating partial molar volumes

    International Nuclear Information System (INIS)

    Carmen Grande, Maria del; Julia, Jorge Alvarez; Barrero, Carmen R.; Marschoff, Carlos M.; Bianchi, Hugo L.

    2006-01-01

    Density and viscosity of (water + acetonitrile) mixtures were measured over the whole composition range at the temperatures: (298.15, 303.15, 308.15, 313.15, and 318.15) K. A new mathematical approach was developed which allows the calculation of the derivatives of density with respect to composition avoiding the appearance of local discontinuities. Thus, reliable partial molar volumes and thermal expansion coefficients were obtained

  15. New finite volume methods for approximating partial differential equations on arbitrary meshes

    International Nuclear Information System (INIS)

    Hermeline, F.

    2008-12-01

    This dissertation presents some new methods of finite volume type for approximating partial differential equations on arbitrary meshes. The main idea lies in solving twice the problem to be dealt with. One addresses the elliptic equations with variable (anisotropic, antisymmetric, discontinuous) coefficients, the parabolic linear or non linear equations (heat equation, radiative diffusion, magnetic diffusion with Hall effect), the wave type equations (Maxwell, acoustics), the elasticity and Stokes'equations. Numerous numerical experiments show the good behaviour of this type of method. (author)

  16. Whole object surface area and volume of partial-view 3D models

    International Nuclear Information System (INIS)

    Mulukutla, Gopal K; Proussevitch, Alexander A; Genareau, Kimberly D; Durant, Adam J

    2017-01-01

    Micro-scale 3D models, important components of many studies in science and engineering, are often used to determine morphological characteristics such as shape, surface area and volume. The application of techniques such as stereoscopic scanning electron microscopy on whole objects often results in ‘partial-view’ models with a portion of object not within the field of view thus not captured in the 3D model. The nature and extent of the surface not captured is dependent on the complex interaction of imaging system attributes (e.g. working distance, viewing angle) with object size, shape and morphology. As a result, any simplistic assumptions in estimating whole object surface area or volume can lead to significant errors. In this study, we report on a novel technique to estimate the physical fraction of an object captured in a partial-view 3D model of an otherwise whole object. This allows a more accurate estimate of surface area and volume. Using 3D models, we demonstrate the robustness of this method and the accuracy of surface area and volume estimates relative to true values. (paper)

  17. Partial molar volume of n-alcohols at infinite dilution in water calculated by means of scaled particle theory.

    Science.gov (United States)

    Graziano, Giuseppe

    2006-04-07

    The partial molar volume of n-alcohols at infinite dilution in water is smaller than the molar volume in the neat liquid phase. It is shown that the formula for the partial molar volume at infinite dilution obtained from the scaled particle theory equation of state for binary hard sphere mixtures is able to reproduce in a satisfactory manner the experimental data over a large temperature range. This finding implies that the packing effects play the fundamental role in determining the partial molar volume at infinite dilution in water also for solutes, such as n-alcohols, forming H bonds with water molecules. Since the packing effects in water are largely related to the small size of its molecules, the latter feature is the ultimate cause of the decrease in partial molar volume associated with the hydrophobic effect.

  18. Does early tetralogy of Fallot total correction give better final lung volumes?

    Science.gov (United States)

    Sadeghi, Hasan Allah; Miri, Seyed Reza; Bakhshandeh, Hooman; Mirmesdagh, Yalda; Paziraee, Nazita

    2013-06-01

    Pulmonary blood flow may affect lung development in adulthood. Early total correction of tetralogy of Fallot may affect development of final lung volumes. We evaluated the effect of age at total correction on lung volumes years after the operation. In a retrospective cohort study on patients with totally corrected tetralogy of Fallot (mean age, 13.40 years at the time of follow-up), forced vital capacity, slow vital capacity, forced expiratory volume in 1 s, and other parameters were measured 154.8 ± 46.25 months after the operation. Comparison were made of 3 groups: ≤2-, 2-8-, and >8-years old at the time of total correction surgery. Among 322 enrolled patients, the mean values of the follow-up spirometry results in ≤2-, 2-8-, >8-year-olds and the percentage of predicted values were respectively: vital capacity: 4.46 ± 0.57 L (107% ± 10.96%), 3.89 ± 0.58 L (91.10% ± 12.25%), 3.25 ± 0.48 L (82.35% ± 10.62%), p volume in 1 s: 4.22 ± 0.63 L (104.84% ± 13.64%), 3.66 ± 0.58 L (90.61% ± 12.59%), 3.02 ± 0.48 L (84.31% ± 12%), p volumes and capacities. It is better to consider total correction for all tetralogy of Fallot patients below 2-years old, or at least below 8-years old, if it is technically possible.

  19. Excess molar volumes and partial molar volumes for (propionitrile + an alkanol) at T = 298.15 K and p = 0.1 MPa

    International Nuclear Information System (INIS)

    Deenadayalu, N.; Bhujrajh, P.

    2006-01-01

    The excess molar volumes and the partial molar volumes for (propionitrile + an alkanol) at T = 298.15 K and at atmospheric pressure are reported. The hydrogen bonding between the OH133;NC groups are discussed in terms of the chain length of the alkanol. The alkanols studied are (methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, and 1-pentanol). The excess molar volume data was fitted to the Redlich-Kister equation The partial molar volumes were calculated from the Redlich-Kister coefficients

  20. Dilatometric measurement of the partial molar volume of water sorbed to durum wheat flour.

    Science.gov (United States)

    Hasegawa, Ayako; Ogawa, Takenobu; Adachi, Shuji

    2013-01-01

    Moisture sorption isotherms were measured at 25 °C for untreated, dry-heated and pre-gelatinized durum wheat flour samples. The isotherms could be expressed by the Guggenheim-Anderson-de Boer equation. The amount of water sorbed to the untreated flour was highest for low water activity, with water sorbed to the pre-gelatinized and dry-heated flour samples following. The dry-heated and pregelatinized flour samples exhibited the same dependence of the moisture content on the partial molar volume of water at 25 °C as the untreated flour. The partial molar volume of water was ca. 9 cm(3)/mol at a moisture content of 0.03 kg-H2O/kg-d.m. The volume increased with increasing moisture content, and reached a constant value of ca. 17.5 cm(3)/mol at a moisture content of 0.2 kg-H2O/kg-d.m. or higher.

  1. Correction for Eddy Current-Induced Echo-Shifting Effect in Partial-Fourier Diffusion Tensor Imaging.

    Science.gov (United States)

    Truong, Trong-Kha; Song, Allen W; Chen, Nan-Kuei

    2015-01-01

    In most diffusion tensor imaging (DTI) studies, images are acquired with either a partial-Fourier or a parallel partial-Fourier echo-planar imaging (EPI) sequence, in order to shorten the echo time and increase the signal-to-noise ratio (SNR). However, eddy currents induced by the diffusion-sensitizing gradients can often lead to a shift of the echo in k-space, resulting in three distinct types of artifacts in partial-Fourier DTI. Here, we present an improved DTI acquisition and reconstruction scheme, capable of generating high-quality and high-SNR DTI data without eddy current-induced artifacts. This new scheme consists of three components, respectively, addressing the three distinct types of artifacts. First, a k-space energy-anchored DTI sequence is designed to recover eddy current-induced signal loss (i.e., Type 1 artifact). Second, a multischeme partial-Fourier reconstruction is used to eliminate artificial signal elevation (i.e., Type 2 artifact) associated with the conventional partial-Fourier reconstruction. Third, a signal intensity correction is applied to remove artificial signal modulations due to eddy current-induced erroneous T2(∗) -weighting (i.e., Type 3 artifact). These systematic improvements will greatly increase the consistency and accuracy of DTI measurements, expanding the utility of DTI in translational applications where quantitative robustness is much needed.

  2. A novel correction factor based on extended volume to complement the conformity index.

    Science.gov (United States)

    Jin, F; Wang, Y; Wu, Y-Z

    2012-08-01

    We propose a modified conformity index (MCI), based on extended volume, that improves on existing indices by correcting for the insensitivity of previous conformity indices to reference dose shape to assess the quality of high-precision radiation therapy and present an evaluation of its application. In this paper, the MCI is similar to the conformity index suggested by Paddick (CI(Paddick)), but with a different correction factor. It is shown for three cases: with an extended target volume, with an extended reference dose volume and without an extended volume. Extended volume is generated by expanding the original volume by 0.1-1.1 cm isotropically. Focusing on the simulation model, measurements of MCI employ a sphere target and three types of reference doses: a sphere, an ellipsoid and a cube. We can constrain the potential advantage of the new index by comparing MCI with CI(Paddick). The measurements of MCI in head-neck cancers treated with intensity-modulated radiation therapy and volumetric-modulated arc therapy provide a window on its clinical practice. The results of MCI for a simulation model and clinical practice are presented and the measurements are corrected for limited spatial resolution. The three types of MCI agree with each other, and comparisons between the MCI and CI(Paddick) are also provided. The results from our analysis show that the proposed MCI can provide more objective and accurate conformity measurement for high-precision radiation therapy. In combination with a dose-volume histogram, it will be a more useful conformity index.

  3. Evaluation of bias-correction methods for ensemble streamflow volume forecasts

    Directory of Open Access Journals (Sweden)

    T. Hashino

    2007-01-01

    Full Text Available Ensemble prediction systems are used operationally to make probabilistic streamflow forecasts for seasonal time scales. However, hydrological models used for ensemble streamflow prediction often have simulation biases that degrade forecast quality and limit the operational usefulness of the forecasts. This study evaluates three bias-correction methods for ensemble streamflow volume forecasts. All three adjust the ensemble traces using a transformation derived with simulated and observed flows from a historical simulation. The quality of probabilistic forecasts issued when using the three bias-correction methods is evaluated using a distributions-oriented verification approach. Comparisons are made of retrospective forecasts of monthly flow volumes for a north-central United States basin (Des Moines River, Iowa, issued sequentially for each month over a 48-year record. The results show that all three bias-correction methods significantly improve forecast quality by eliminating unconditional biases and enhancing the potential skill. Still, subtle differences in the attributes of the bias-corrected forecasts have important implications for their use in operational decision-making. Diagnostic verification distinguishes these attributes in a context meaningful for decision-making, providing criteria to choose among bias-correction methods with comparable skill.

  4. White matter atlas of the human spinal cord with estimation of partial volume effect.

    Science.gov (United States)

    Lévy, S; Benhamou, M; Naaman, C; Rainville, P; Callot, V; Cohen-Adad, J

    2015-10-01

    Template-based analysis has proven to be an efficient, objective and reproducible way of extracting relevant information from multi-parametric MRI data. Using common atlases, it is possible to quantify MRI metrics within specific regions without the need for manual segmentation. This method is therefore free from user-bias and amenable to group studies. While template-based analysis is common procedure for the brain, there is currently no atlas of the white matter (WM) spinal pathways. The goals of this study were: (i) to create an atlas of the white matter tracts compatible with the MNI-Poly-AMU template and (ii) to propose methods to quantify metrics within the atlas that account for partial volume effect. The WM atlas was generated by: (i) digitalizing an existing WM atlas from a well-known source (Gray's Anatomy), (ii) registering this atlas to the MNI-Poly-AMU template at the corresponding slice (C4 vertebral level), (iii) propagating the atlas throughout all slices of the template (C1 to T6) using regularized diffeomorphic transformations and (iv) computing partial volume values for each voxel and each tract. Several approaches were implemented and validated to quantify metrics within the atlas, including weighted-average and Gaussian mixture models. Proof-of-concept application was done in five subjects for quantifying magnetization transfer ratio (MTR) in each tract of the atlas. The resulting WM atlas showed consistent topological organization and smooth transitions along the rostro-caudal axis. The median MTR across tracts was 26.2. Significant differences were detected across tracts, vertebral levels and subjects, but not across laterality (right-left). Among the different tested approaches to extract metrics, the maximum a posteriori showed highest performance with respect to noise, inter-tract variability, tract size and partial volume effect. This new WM atlas of the human spinal cord overcomes the biases associated with manual delineation and partial

  5. Validation of attenuation-corrected equilibrium radionuclide angiographic determinations of right ventricular volume: comparison with cast-validated biplane cineventriculography

    International Nuclear Information System (INIS)

    Dell'Italia, L.J.; Starling, M.R.; Walsh, R.A.; Badke, F.R.; Lasher, J.C.; Blumhardt, R.

    1985-01-01

    To determine the accuracy of attenuation-corrected equilibrium radionuclide angiographic determinations of right ventricular volumes, the authors initially studied 14 postmortem human right ventricular casts by water displacement and biplane cineventriculography. Biplane cineventriculographic right ventricular cast volumes, calculated by a modification of Simpson's rule algorithm, correlated well with right ventricular cast volumes measured by water displacement (r = .97, y = 8 + 0.88x, SEE = 6 ml). Moreover, the mean volumes obtained by both methods were no different (73 +/- 28 vs 73 +/- 25 ml). Subsequently, they studied 16 patients by both biplane cineventriculography and equilibrium radionuclide angiography. The uncorrected radionuclide right ventricular volumes were calculated by normalizing background corrected end-diastolic and end-systolic counts from hand-drawn regions of interest obtained by phase analysis for cardiac cycles processed, frame rate, and blood sample counts. Attenuation correction was performed by a simple geometric method. The attenuation-corrected radionuclide right ventricular end-diastolic volumes correlated with the cineventriculographic end-diastolic volumes (r = .91, y = 3 + 0.92x, SEE = 27 ml). Similarly, the attenuation-corrected radionuclide right ventricular end-systolic volumes correlated with the cineventriculographic end-systolic volumes (r = .93, y = - 1 + 0.91x, SEE = 16 ml). Also, the mean attenuation-corrected radionuclide end-diastolic and end-systolic volumes were no different than the average cineventriculographic end-diastolic and end-systolic volumes (160 +/- 61 and 83 +/- 44 vs 170 +/- 61 and 86 +/- 43 ml, respectively)

  6. Evaluation of a three-dimensional ultrasound localisation system incorporating probe pressure correction for use in partial breast irradiation.

    Science.gov (United States)

    Harris, E J; Symonds-Taylor, R; Treece, G M; Gee, A H; Prager, R W; Brabants, P; Evans, P M

    2009-10-01

    This work evaluates a three-dimensional (3D) freehand ultrasound-based localisation system with new probe pressure correction for use in partial breast irradiation. Accuracy and precision of absolute position measurement was measured as a function of imaging depth (ID), object depth, scanning direction and time using a water phantom containing crossed wires. To quantify the improvement in accuracy due to pressure correction, 3D scans of a breast phantom containing ball bearings were obtained with and without pressure. Ball bearing displacements were then measured with and without pressure correction. Using a single scan direction (for all imaging depths), the mean error was <1.3 mm, with the exception of the wires at 68.5 mm imaged with an ID of 85 mm, which gave a mean error of -2.3 mm. Precision was greater than 1 mm for any single scan direction. For multiple scan directions, precision was within 1.7 mm. Probe pressure corrections of between 0 mm and 2.2 mm have been observed for pressure displacements of 1.1 mm to 4.2 mm. Overall, anteroposterior position measurement accuracy increased from 2.2 mm to 1.6 mm and to 1.4 mm for the two opposing scanning directions. Precision is comparable to that reported for other commercially available ultrasound localisation systems, provided that 3D image acquisition is performed in the same scan direction. The existing temporal calibration is imperfect and a "per installation" calibration would further improve the accuracy and precision. Probe pressure correction was shown to improve the accuracy and will be useful for the localisation of the excision cavity in partial breast radiotherapy.

  7. Partial-Interval Estimation of Count: Uncorrected and Poisson-Corrected Error Levels

    Science.gov (United States)

    Yoder, Paul J.; Ledford, Jennifer R.; Harbison, Amy L.; Tapp, Jon T.

    2018-01-01

    A simulation study that used 3,000 computer-generated event streams with known behavior rates, interval durations, and session durations was conducted to test whether the main and interaction effects of true rate and interval duration affect the error level of uncorrected and Poisson-transformed (i.e., "corrected") count as estimated by…

  8. A Label Correcting Algorithm for Partial Disassembly Sequences in the Production Planning for End-of-Life Products

    Directory of Open Access Journals (Sweden)

    Pei-Fang (Jennifer Tsai

    2012-01-01

    Full Text Available Remanufacturing of used products has become a strategic issue for cost-sensitive businesses. Due to the nature of uncertain supply of end-of-life (EoL products, the reverse logistic can only be sustainable with a dynamic production planning for disassembly process. This research investigates the sequencing of disassembly operations as a single-period partial disassembly optimization (SPPDO problem to minimize total disassembly cost. AND/OR graph representation is used to include all disassembly sequences of a returned product. A label correcting algorithm is proposed to find an optimal partial disassembly plan if a specific reusable subpart is retrieved from the original return. Then, a heuristic procedure that utilizes this polynomial-time algorithm is presented to solve the SPPDO problem. Numerical examples are used to demonstrate the effectiveness of this solution procedure.

  9. Evaluation of the reconstruction method and effect of partial volume in brain scintiscanning; Avaliacao do metodo de reconstrucao e efeito do volume parcial em cintilografia cerebral

    Energy Technology Data Exchange (ETDEWEB)

    Pinheiro, Monica Araujo

    2016-10-01

    Alzheimer's disease is a neurodegenerative disorder, on which occurs a progressive and irreversible destruction of neurons. According to the World Health Organization (WHO) 35.6 million people are living with dementia, being recommended that governments prioritize early diagnosis techniques. Laboratory and psychological tests for cognitive assessment are conducted and further complemented by neurological imaging from nuclear medicine exams in order to establish an accurate diagnosis. The image quality evaluation and reconstruction process effects are important tools in clinical routine. In the present work, these quality parameters were studied, and the effects of partial volume (PVE) for lesions of different sizes and geometries that are attributed to the limited resolution of the equipment. In dementia diagnosis, this effect can be confused with intake losses due to cerebral cortex atrophy. The evaluation was conducted by two phantoms of different shapes as suggested by (a) American College of Radiology (ACR) and (b) National Electrical Manufacturers Association (NEMA) for Contrast, Contrast-to-Noise Ratio (CNR) and Recovery Coefficient (RC) calculation versus lesions shape and size. Technetium-99m radionuclide was used in a local brain scintigraphy protocol, for proportions lesion to background of 2:1, 4:1, 6:1, 8:1 and 10:1. Fourteen reconstruction methods were used for each concentration applying different filters and algorithms. Before the analysis of all image properties, the conclusion is that the predominant effect is the partial volume, leading to errors of measurement of more than 80%. Furthermore, it was demonstrate that the most effective method of reconstruction is FBP with Metz filter, providing better contrast and contrast to noise ratio results. In addition, this method shows the best Recovery Coefficients correction for each lesion. The ACR phantom showed the best results assigned to a more precise reconstruction of a cylinder, which does not

  10. On a relationship between molecular polarizability and partial molar volume in water.

    Science.gov (United States)

    Ratkova, Ekaterina L; Fedorov, Maxim V

    2011-12-28

    We reveal a universal relationship between molecular polarizability (a single-molecule property) and partial molar volume in water that is an ensemble property characterizing solute-solvent systems. Since both of these quantities are of the key importance to describe solvation behavior of dissolved molecular species in aqueous solutions, the obtained relationship should have a high impact in chemistry, pharmaceutical, and life sciences as well as in environments. We demonstrated that the obtained relationship between the partial molar volume in water and the molecular polarizability has in general a non-homogeneous character. We performed a detailed analysis of this relationship on a set of ~200 organic molecules from various chemical classes and revealed its fine well-organized structure. We found that this structure strongly depends on the chemical nature of the solutes and can be rationalized in terms of specific solute-solvent interactions. Efficiency and universality of the proposed approach was demonstrated on an external test set containing several dozens of polyfunctional and druglike molecules.

  11. Calculation of partial molar volume of components in supercritical ammonia synthesis system

    Institute of Scientific and Technical Information of China (English)

    Cunwen WANG; Chuanbo YU; Wen CHEN; Weiguo WANG; Yuanxin WU; Junfeng ZHANG

    2008-01-01

    The partial molar volumes of components in supercritical ammonia synthesis system are calculated in detail by the calculation formula of partial molar volume derived from the R-K equation of state under different conditions. The objectives are to comprehend phase beha-vior of components and to provide the theoretic explana-tion and guidance for probing novel processes of ammonia synthesis under supercritical conditions. The conditions of calculation are H2/N2= 3, at a concentra-tion of NH3 in synthesis gas ranging from 2% to 15%, Concentration of medium in supercritical ammonia syn-thesis system ranging from 20% to 50%, temperature ran-ging from 243 K to 699 K and pressure ranging from 0.1 MPa to 187 MPa. The results show that the ammonia synthesis system can reach supercritical state by adding a suitable supercritical medium and then controlling the reaction conditions. It is helpful for the supercritical ammonia synthesis that medium reaches supercritical state under the conditions of the corresponding total pres-sure and components near the normal temperature or near the critical temperature of medium or in the range of tem-perature of industrialized ammonia synthesis.

  12. Statistical properties of single-mode fiber coupling of satellite-to-ground laser links partially corrected by adaptive optics.

    Science.gov (United States)

    Canuet, Lucien; Védrenne, Nicolas; Conan, Jean-Marc; Petit, Cyril; Artaud, Geraldine; Rissons, Angelique; Lacan, Jerome

    2018-01-01

    In the framework of satellite-to-ground laser downlinks, an analytical model describing the variations of the instantaneous coupled flux into a single-mode fiber after correction of the incoming wavefront by partial adaptive optics (AO) is presented. Expressions for the probability density function and the cumulative distribution function as well as for the average fading duration and fading duration distribution of the corrected coupled flux are given. These results are of prime interest for the computation of metrics related to coded transmissions over correlated channels, and they are confronted by end-to-end wave-optics simulations in the case of a geosynchronous satellite (GEO)-to-ground and a low earth orbit satellite (LEO)-to-ground scenario. Eventually, the impact of different AO performances on the aforementioned fading duration distribution is analytically investigated for both scenarios.

  13. Hydrophobic hydration and the anomalous partial molar volumes in ethanol-water mixtures

    International Nuclear Information System (INIS)

    Tan, Ming-Liang; Te, Jerez; Cendagorta, Joseph R.; Miller, Benjamin T.; Brooks, Bernard R.; Ichiye, Toshiko

    2015-01-01

    The anomalous behavior in the partial molar volumes of ethanol-water mixtures at low concentrations of ethanol is studied using molecular dynamics simulations. Previous work indicates that the striking minimum in the partial molar volume of ethanol V E as a function of ethanol mole fraction X E is determined mainly by water-water interactions. These results were based on simulations that used one water model for the solute-water interactions but two different water models for the water-water interactions. This is confirmed here by using two more water models for the water-water interactions. Furthermore, the previous work indicates that the initial decrease is caused by association of the hydration shells of the hydrocarbon tails, and the minimum occurs at the concentration where all of the hydration shells are touching each other. Thus, the characteristics of the hydration of the tail that cause the decrease and the features of the water models that reproduce this type of hydration are also examined here. The results show that a single-site multipole water model with a charge distribution that mimics the large quadrupole and the p-orbital type electron density out of the molecular plane has “brittle” hydration with hydrogen bonds that break as the tails touch, which reproduces the deep minimum. However, water models with more typical site representations with partial charges lead to flexible hydration that tends to stay intact, which produces a shallow minimum. Thus, brittle hydration may play an essential role in hydrophobic association in water

  14. Target volume delineation in external beam partial breast irradiation: Less inter-observer variation with preoperative- compared to postoperative delineation

    International Nuclear Information System (INIS)

    Leij, Femke van der; Elkhuizen, Paula H.M.; Janssen, Tomas M.; Poortmans, Philip; Sangen, Maurice van der; Scholten, Astrid N.; Vliet-Vroegindeweij, Corine van; Boersma, Liesbeth J.

    2014-01-01

    The challenge of adequate target volume definition in external beam partial breast irradiation (PBI) could be overcome with preoperative irradiation, due to less inter-observer variation. We compared the target volume delineation for external beam PBI on preoperative versus postoperative CT scans of twenty-four breast cancer patients

  15. Target volume delineation in external beam partial breast irradiation: less inter-observer variation with preoperative- compared to postoperative delineation

    NARCIS (Netherlands)

    Leij, F. van der; Elkhuizen, P.H.M.; Janssen, T.M.; Poortmans, P.M.P.; Sangen, M. van der; Scholten, A.N.; Vliet-Vroegindeweij, C. van; Boersma, L.J.

    2014-01-01

    The challenge of adequate target volume definition in external beam partial breast irradiation (PBI) could be overcome with preoperative irradiation, due to less inter-observer variation. We compared the target volume delineation for external beam PBI on preoperative versus postoperative CT scans of

  16. Count-based left ventricular volume determination utilizing a left posterior oblique view for attenuation correction

    International Nuclear Information System (INIS)

    Rabinovitch, M.A.; Kalff, V.; Koral, K.

    1984-01-01

    This study aimed to determine the inherent error of the left ventricular volume measurement from the gated equilibrium blood pool scintigram utilizing the count-based technique. The study population consisted of 26 patients who had undergone biplane contrast ventriculography. The patients were imaged with a parallel-hole collimator in the left anterior oblique position showing the septum to best advantage. A reference blood sample was counted and radionuclide volumes calculated without correction for attenuation. Attenuation corrected volumes were derived with the factor 1/e/sup -/+d/, where d = distance from skin marker to center of the left ventricle in the orthogonal left posterior oblique view and μ = linear attenuation coefficient. A series of μ values from 0.08 to 0.15 cm -1 was evaluated. The tightest 95% confidence limits achieved for an end-diastolic 150-ml ventricle were +/- 44ml, and for an end-systolic 75-ml ventricle +/- 32 ml. In view of the magnitude of inherent error, the count-based volume measurement may be more suitable for group analyses and in cases in which an individual patient serves as his own control

  17. Corrections to the Walker-Thompson estimate of the cascade volume

    International Nuclear Information System (INIS)

    Swaminarayan, S.; Nastasi, M.

    2009-01-01

    Sigmund [P. Sigmund, Appl. Phys. Lett. 25 (1974) 169] analytically predicted that the ratio of cascade volume to energy distribution volume should follow a universal curve that is sigmoidal in shape. Subsequent Monte Carlo simulations by Walker and Thompson [R.S. Walker, D.A. Thompson, Radiat. Eff. 37 (1978) 113] showed that although this curve is sigmoidal in shape, the curve is different for different materials with large deviations from Sigmund's prediction at high M 2 /M 1 . Our analysis of the Walker and Thompson approach has revealed an error in the analytical equations used. A correct analysis of volume ratios using a different set of equations is presented. Analysis of data produced by SRIM [J.F. Ziegler, J.P. Biersack, U. Littmark, in: The Stopping and Range of Ions in solids, Pergamon, New York, 1985] (Monte Carlo) simulations gives results that are in good agreement with Sigmund's predictions.

  18. Partial molar volume and isentropic compressibility of symmetrical and asymmetrical quaternary ammonium bromides in aqueous solution

    International Nuclear Information System (INIS)

    Moreno, Nicolás; Buchner, Richard; Vargas, Edgar F.

    2015-01-01

    Highlights: • Structural effects of the cations on surrounding water molecules are discussed. • Alkyl-chain geometry determines the hydration of Bu 4 N + isomers. • The “compactness” in the hydration shells varies significantly among the isomers. - Abstract: Values of apparent molar volume and isentropic compressibility of symmetric and asymmetric isomers of tetrabutylammonium bromide, namely tetra-n-butylammonium bromide, tetra-iso-butylammonium bromide, tetra-sec-butylammonium bromide, di-n-butyl-di-iso-butylammonium bromide and di-n-butyl-di-sec-butylammonium bromide, in aqueous solution were determined from density and speed of sound measurements. These properties were obtained as a function of molal concentration within the range of 0.01 < m/mol · kg −1 < 0.1 covering temperatures from 278.15 ⩽ T/K ⩽ 293.15. The partial molar volumes and the apparent isentropic molar compressibility at infinite dilution were calculated and their dependence on temperature examined. The results show that cations with sec-butyl chains have larger structural volumes compared to those with iso-butyl chains. In addition, cations with sec-butyl chains induce smaller structural changes in their hydration shell than the others

  19. In Vivo Gene Therapy of Hemophilia B: Sustained Partial Correction in Factor IX-Deficient Dogs

    Science.gov (United States)

    Kay, Mark A.; Rothenberg, Steven; Landen, Charles N.; Bellinger, Dwight A.; Leland, Frances; Toman, Carol; Finegold, Milton; Thompson, Arthur R.; Read, M. S.; Brinkhous, Kenneth M.; Woo, Savio L. C.

    1993-10-01

    The liver represents a model organ for gene therapy. A method has been developed for hepatic gene transfer in vivo by the direct infusion of recombinant retroviral vectors into the portal vasculature, which results in the persistent expression of exogenous genes. To determine if these technologies are applicable for the treatment of hemophilia B patients, preclinical efficacy studies were done in a hemophilia B dog model. When the canine factor IX complementary DNA was transduced directly into the hepatocytes of affected dogs in vivo, the animals constitutively expressed low levels of canine factor IX for more than 5 months. Persistent expression of the clotting. factor resulted in reductions of whole blood clotting and partial thromboplastin times of the treated animals. Thus, long-term treatment of hemophilia B patients may be feasible by direct hepatic gene therapy in vivo.

  20. Partial correction of a severe molecular defect in hemophilia A, because of errors during expression of the factor VIII gene

    Energy Technology Data Exchange (ETDEWEB)

    Young, M.; Antonarakis, S.E. [Univ. of Geneva (Switzerland); Inaba, Hiroshi [Tokyo Medical College (Japan)] [and others

    1997-03-01

    Although the molecular defect in patients in a Japanese family with mild to moderately severe hemophilia A was a deletion of a single nucleotide T within an A{sub 8}TA{sub 2} sequence of exon 14 of the factor VIII gene, the severity of the clinical phenotype did not correspond to that expected of a frameshift mutation. A small amount of functional factor VIII protein was detected in the patient`s plasma. Analysis of DNA and RNA molecules from normal and affected individuals and in vitro transcription/translation suggested a partial correction of the molecular defect, because of the following: (i) DNA replication/RNA transcription errors resulting in restoration of the reading frame and/or (ii) {open_quotes}ribosomal frameshifting{close_quotes} resulting in the production of normal factor VIII polypeptide and, thus, in a milder than expected hemophilia A. All of these mechanisms probably were promoted by the longer run of adenines, A{sub 10} instead of A{sub 8}TA{sub 2}, after the delT. Errors in the complex steps of gene expression therefore may partially correct a severe frameshift defect and ameliorate an expected severe phenotype. 36 refs., 6 figs.

  1. Partial versus complete fundoplication for the correction of pediatric GERD: a systematic review and meta-analysis.

    Directory of Open Access Journals (Sweden)

    Peter Glen

    Full Text Available There is no consensus as to what extent of "wrap" is required in a fundoplication for correction of gastroesophageal reflux disease (GERD.To evaluate if a complete (360 degree or partial fundoplication gives better control of GERD.A systematic search of MEDLINE and Scopus identified interventional and observational studies of fundoplication in children. Screening identified those comparing techniques. The primary outcome was recurrence of GERD following surgery. Dysphagia and complications were secondary outcomes of interest. Meta-analysis was performed when appropriate. Study quality was assessed using the Cochrane Risk of Bias Tool.2289 abstracts were screened, yielding 2 randomized controlled trials (RCTs and 12 retrospective cohort studies. The RCTs were pooled. There was no difference in surgical success between partial and complete fundoplication, OR 1.33 [0.67,2.66]. In the 12 cohort studies, 3 (25% used an objective assessment of the surgery, one of which showed improved outcomes with complete fundoplication. Twenty-five different complications were reported; common were dysphagia and gas-bloat syndrome. Overall study quality was poor.The comparison of partial fundoplication with complete fundoplication warrants further study. The evidence does not demonstrate superiority of one technique. The lack of high quality RCTs and the methodological heterogeneity of observational studies limits a powerful meta-analysis.

  2. A consistent model for the equilibrium thermodynamic functions of partially ionized flibe plasma with Coulomb corrections

    International Nuclear Information System (INIS)

    Zaghloul, Mofreh R.

    2003-01-01

    Flibe (2LiF-BeF2) is a molten salt that has been chosen as the coolant and breeding material in many design studies of the inertial confinement fusion (ICF) chamber. Flibe plasmas are to be generated in the ICF chamber in a wide range of temperatures and densities. These plasmas are more complex than the plasma of any single chemical species. Nevertheless, the composition and thermodynamic properties of the resulting flibe plasmas are needed for the gas dynamics calculations and the determination of other design parameters in the ICF chamber. In this paper, a simple consistent model for determining the detailed plasma composition and thermodynamic functions of high-temperature, fully dissociated and partially ionized flibe gas is presented and used to calculate different thermodynamic properties of interest to fusion applications. The computed properties include the average ionization state; kinetic pressure; internal energy; specific heats; adiabatic exponent, as well as the sound speed. The presented results are computed under the assumptions of local thermodynamic equilibrium (LTE) and electro-neutrality. A criterion for the validity of the LTE assumption is presented and applied to the computed results. Other attempts in the literature are assessed with their implied inaccuracies pointed out and discussed

  3. Kalisphera: an analytical tool to reproduce the partial volume effect of spheres imaged in 3D

    International Nuclear Information System (INIS)

    Tengattini, Alessandro; Andò, Edward

    2015-01-01

    In experimental mechanics, where 3D imaging is having a profound effect, spheres are commonly adopted for their simplicity and for the ease of their modeling. In this contribution we develop an analytical tool, ‘kalisphera’, to produce 3D raster images of spheres including their partial volume effect. This allows us to evaluate the metrological performance of existing image-based measurement techniques (knowing a priori the ground truth). An advanced application of ‘kalisphera’ is developed here to identify and accurately characterize spheres in real 3D x-ray tomography images with the objective of improving trinarization and contact detection. The effect of the common experimental imperfections is assessed and the overall performance of the tool tested on real images. (paper)

  4. Nuclear piping criteria for Advanced Light-Water Reactors, Volume 1--Failure mechanisms and corrective actions

    International Nuclear Information System (INIS)

    Anon.

    1993-01-01

    This WRC Bulletin concentrates on the major failure mechanisms observed in nuclear power plant piping during the past three decades and on corrective actions taken to minimize or eliminate such failures. These corrective actions are applicable to both replacement piping and the next generation of light-water reactors. This WRC Bulletin was written with the objective of meeting a need for piping criteria in Advanced Light-Water Reactors, but there is application well beyond the LWR industry. This Volume, in particular, is equally applicable to current nuclear power plants, fossil-fueled power plants, and chemical plants including petrochemical. Implementation of the recommendations for mitigation of specific problems should minimize severe failures or cracking and provide substantial economic benefit. This volume uses a case history approach to high-light various failure mechanisms and the corrective actions used to resolve such failures. Particular attention is given to those mechanisms leading to severe piping failures, where severe denotes complete severance, large ''fishmouth'' failures, or long throughwall cracks releasing a minimum of 50 gpm. The major failure mechanisms causing severe failure are erosion-corrosion and vibrational fatigue. Stress corrosion cracking also has been a common problem in nuclear piping systems. In addition thermal fatigue due to mixing-tee and to thermal stratification also is discussed as is microbiologically-induced corrosion. Finally, water hammer, which represents the ultimate in internally-generated dynamic high-energy loads, is discussed

  5. Reductions in Corpus Callosum Volume Partially Mediate Effects of Prenatal Alcohol Exposure on IQ

    Directory of Open Access Journals (Sweden)

    Stevie C. Biffen

    2018-01-01

    Full Text Available Disproportionate volume reductions in the basal ganglia, corpus callosum (CC and hippocampus have been reported in children with prenatal alcohol exposure (PAE. However, few studies have investigated these reductions in high prevalence communities, such as the Western Cape Province of South Africa, and only one study made use of manual tracing, the gold standard of volumetric analysis. The present study examined the effects of PAE on subcortical neuroanatomy using manual tracing and the relation of volumetric reductions in these regions to IQ and performance on the California Verbal Learning Test-Children's Version (CVLT-C, a list learning task sensitive to PAE. High-resolution T1-weighted images were acquired, using a sequence optimized for morphometric neuroanatomical analysis, on a Siemens 3T Allegra MRI scanner from 71 right-handed, 9- to 11-year-old children [9 fetal alcohol syndrome (FAS, 19 partial FAS (PFAS, 24 non-syndromal heavily exposed (HE and 19 non-exposed controls]. Frequency of maternal drinking was ascertained prospectively during pregnancy using timeline follow-back interviews. PAE was examined in relation to volumes of the CC and left and right caudate nuclei, nucleus accumbens and hippocampi. All structures were manually traced using Multitracer. Higher levels of PAE were associated with reductions in CC volume after adjustment for TIV. Although the effect of PAE on CC was confounded with smoking and lead exposure, additional analyses showed that it was not accounted for by these exposures. Amongst dysmorphic children, smaller CC was associated with poorer IQ and CVLT-C scores and statistically mediated the effect of PAE on IQ. In addition, higher levels of PAE were associated with bilateral volume reductions in caudate nuclei and hippocampi, effects that remained significant after control for TIV, child sex and age, socioeconomic status, maternal smoking during pregnancy, and childhood lead exposure. These data confirm

  6. A New Approach for Deep Gray Matter Analysis Using Partial-Volume Estimation.

    Science.gov (United States)

    Bonnier, Guillaume; Kober, Tobias; Schluep, Myriam; Du Pasquier, Renaud; Krueger, Gunnar; Meuli, Reto; Granziera, Cristina; Roche, Alexis

    2016-01-01

    The existence of partial volume effects in brain MR images makes it challenging to understand physio-pathological alterations underlying signal changes due to pathology across groups of healthy subjects and patients. In this study, we implement a new approach to disentangle gray and white matter alterations in the thalamus and the basal ganglia. The proposed method was applied to a cohort of early multiple sclerosis (MS) patients and healthy subjects to evaluate tissue-specific alterations related to diffuse inflammatory or neurodegenerative processes. Forty-three relapsing-remitting MS patients and nineteen healthy controls underwent 3T MRI including: (i) fluid-attenuated inversion recovery, double inversion recovery, magnetization-prepared gradient echo for lesion count, and (ii) T1 relaxometry. We applied a partial volume estimation algorithm to T1 relaxometry maps to gray and white matter local concentrations as well as T1 values characteristic of gray and white matter in the thalamus and the basal ganglia. Statistical tests were performed to compare groups in terms of both global T1 values, tissue characteristic T1 values, and tissue concentrations. Significant increases in global T1 values were observed in the thalamus (p = 0.038) and the putamen (p = 0.026) in RRMS patients compared to HC. In the Thalamus, the T1 increase was associated with a significant increase in gray matter characteristic T1 (p = 0.0016) with no significant effect in white matter. The presented methodology provides additional information to standard MR signal averaging approaches that holds promise to identify the presence and nature of diffuse pathology in neuro-inflammatory and neurodegenerative diseases.

  7. Quadrupole terms in the Maxwell equations: Born energy, partial molar volume, and entropy of ions.

    Science.gov (United States)

    Slavchov, Radomir I; Ivanov, Tzanko I

    2014-02-21

    A new equation of state relating the macroscopic quadrupole moment density Q to the gradient of the field ∇E in an isotropic fluid is derived: Q = αQ(∇E - U∇·E/3), where the quadrupolarizability αQ is proportional to the squared molecular quadrupole moment. Using this equation of state, a generalized expression for the Born energy of an ion dissolved in quadrupolar solvent is obtained. It turns out that the potential and the energy of a point charge in a quadrupolar medium are finite. From the obtained Born energy, the partial molar volume and the partial molar entropy of a dissolved ion follow. Both are compared to experimental data for a large number of simple ions in aqueous solutions. From the comparison the value of the quadrupolar length LQ is determined, LQ = (αQ/3ɛ)(1/2) = 1-4 Å. Data for ion transfer from aqueous to polar oil solution are analyzed, which allowed for the determination of the quadrupolarizability of nitrobenzene.

  8. Cardiac motion correction based on partial angle reconstructed images in x-ray CT

    International Nuclear Information System (INIS)

    Kim, Seungeon; Chang, Yongjin; Ra, Jong Beom

    2015-01-01

    Purpose: Cardiac x-ray CT imaging is still challenging due to heart motion, which cannot be ignored even with the current rotation speed of the equipment. In response, many algorithms have been developed to compensate remaining motion artifacts by estimating the motion using projection data or reconstructed images. In these algorithms, accurate motion estimation is critical to the compensated image quality. In addition, since the scan range is directly related to the radiation dose, it is preferable to minimize the scan range in motion estimation. In this paper, the authors propose a novel motion estimation and compensation algorithm using a sinogram with a rotation angle of less than 360°. The algorithm estimates the motion of the whole heart area using two opposite 3D partial angle reconstructed (PAR) images and compensates the motion in the reconstruction process. Methods: A CT system scans the thoracic area including the heart over an angular range of 180° + α + β, where α and β denote the detector fan angle and an additional partial angle, respectively. The obtained cone-beam projection data are converted into cone-parallel geometry via row-wise fan-to-parallel rebinning. Two conjugate 3D PAR images, whose center projection angles are separated by 180°, are then reconstructed with an angular range of β, which is considerably smaller than a short scan range of 180° + α. Although these images include limited view angle artifacts that disturb accurate motion estimation, they have considerably better temporal resolution than a short scan image. Hence, after preprocessing these artifacts, the authors estimate a motion model during a half rotation for a whole field of view via nonrigid registration between the images. Finally, motion-compensated image reconstruction is performed at a target phase by incorporating the estimated motion model. The target phase is selected as that corresponding to a view angle that is orthogonal to the center view angles of

  9. Cardiac motion correction based on partial angle reconstructed images in x-ray CT

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Seungeon; Chang, Yongjin; Ra, Jong Beom, E-mail: jbra@kaist.ac.kr [Department of Electrical Engineering, KAIST, Daejeon 305-701 (Korea, Republic of)

    2015-05-15

    Purpose: Cardiac x-ray CT imaging is still challenging due to heart motion, which cannot be ignored even with the current rotation speed of the equipment. In response, many algorithms have been developed to compensate remaining motion artifacts by estimating the motion using projection data or reconstructed images. In these algorithms, accurate motion estimation is critical to the compensated image quality. In addition, since the scan range is directly related to the radiation dose, it is preferable to minimize the scan range in motion estimation. In this paper, the authors propose a novel motion estimation and compensation algorithm using a sinogram with a rotation angle of less than 360°. The algorithm estimates the motion of the whole heart area using two opposite 3D partial angle reconstructed (PAR) images and compensates the motion in the reconstruction process. Methods: A CT system scans the thoracic area including the heart over an angular range of 180° + α + β, where α and β denote the detector fan angle and an additional partial angle, respectively. The obtained cone-beam projection data are converted into cone-parallel geometry via row-wise fan-to-parallel rebinning. Two conjugate 3D PAR images, whose center projection angles are separated by 180°, are then reconstructed with an angular range of β, which is considerably smaller than a short scan range of 180° + α. Although these images include limited view angle artifacts that disturb accurate motion estimation, they have considerably better temporal resolution than a short scan image. Hence, after preprocessing these artifacts, the authors estimate a motion model during a half rotation for a whole field of view via nonrigid registration between the images. Finally, motion-compensated image reconstruction is performed at a target phase by incorporating the estimated motion model. The target phase is selected as that corresponding to a view angle that is orthogonal to the center view angles of

  10. Goldmann tonometry tear film error and partial correction with a shaped applanation surface.

    Science.gov (United States)

    McCafferty, Sean J; Enikov, Eniko T; Schwiegerling, Jim; Ashley, Sean M

    2018-01-01

    The aim of the study was to quantify the isolated tear film adhesion error in a Goldmann applanation tonometer (GAT) prism and in a correcting applanation tonometry surface (CATS) prism. The separation force of a tonometer prism adhered by a tear film to a simulated cornea was measured to quantify an isolated tear film adhesion force. Acrylic hemispheres (7.8 mm radius) used as corneas were lathed over the apical 3.06 mm diameter to simulate full applanation contact with the prism surface for both GAT and CATS prisms. Tear film separation measurements were completed with both an artificial tear and fluorescein solutions as a fluid bridge. The applanation mire thicknesses were measured and correlated with the tear film separation measurements. Human cadaver eyes were used to validate simulated cornea tear film separation measurement differences between the GAT and CATS prisms. The CATS prism tear film adhesion error (2.74±0.21 mmHg) was significantly less than the GAT prism (4.57±0.18 mmHg, p film adhesion error was independent of applanation mire thickness ( R 2 =0.09, p =0.04). Fluorescein produces more tear film error than artificial tears (+0.51±0.04 mmHg; p film adhesion error (1.40±0.51 mmHg) was significantly less than that of the GAT prism (3.30±0.38 mmHg; p =0.002). Measured GAT tear film adhesion error is more than previously predicted. A CATS prism significantly reduced tear film adhesion error bŷ41%. Fluorescein solution increases the tear film adhesion compared to artificial tears, while mire thickness has a negligible effect.

  11. Goldmann tonometry tear film error and partial correction with a shaped applanation surface

    Directory of Open Access Journals (Sweden)

    McCafferty SJ

    2018-01-01

    Full Text Available Sean J McCafferty,1–4 Eniko T Enikov,5 Jim Schwiegerling,2,3 Sean M Ashley1,3 1Intuor Technologies, 2Department of Ophthalmology, University of Arizona College of Medicine, 3University of Arizona College of Optical Science, 4Arizona Eye Consultants, 5Department of Mechanical and Aerospace, University of Arizona College of Engineering, Tucson, AZ, USA Purpose: The aim of the study was to quantify the isolated tear film adhesion error in a Goldmann applanation tonometer (GAT prism and in a correcting applanation tonometry surface (CATS prism.Methods: The separation force of a tonometer prism adhered by a tear film to a simulated cornea was measured to quantify an isolated tear film adhesion force. Acrylic hemispheres (7.8 mm radius used as corneas were lathed over the apical 3.06 mm diameter to simulate full applanation contact with the prism surface for both GAT and CATS prisms. Tear film separation measurements were completed with both an artificial tear and fluorescein solutions as a fluid bridge. The applanation mire thicknesses were measured and correlated with the tear film separation measurements. Human cadaver eyes were used to validate simulated cornea tear film separation measurement differences between the GAT and CATS prisms.Results: The CATS prism tear film adhesion error (2.74±0.21 mmHg was significantly less than the GAT prism (4.57±0.18 mmHg, p<0.001. Tear film adhesion error was independent of applanation mire thickness (R2=0.09, p=0.04. Fluorescein produces more tear film error than artificial tears (+0.51±0.04 mmHg; p<0.001. Cadaver eye validation indicated the CATS prism’s tear film adhesion error (1.40±0.51 mmHg was significantly less than that of the GAT prism (3.30±0.38 mmHg; p=0.002.Conclusion: Measured GAT tear film adhesion error is more than previously predicted. A CATS prism significantly reduced tear film adhesion error by ~41%. Fluorescein solution increases the tear film adhesion compared to

  12. Impact of residual and intrafractional errors on strategy of correction for image-guided accelerated partial breast irradiation

    Directory of Open Access Journals (Sweden)

    Guo Xiao-Mao

    2010-10-01

    Full Text Available Abstract Background The cone beam CT (CBCT guided radiation can reduce the systematic and random setup errors as compared to the skin-mark setup. However, the residual and intrafractional (RAIF errors are still unknown. The purpose of this paper is to investigate the magnitude of RAIF errors and correction action levels needed in cone beam computed tomography (CBCT guided accelerated partial breast irradiation (APBI. Methods Ten patients were enrolled in the prospective study of CBCT guided APBI. The postoperative tumor bed was irradiated with 38.5 Gy in 10 fractions over 5 days. Two cone-beam CT data sets were obtained with one before and one after the treatment delivery. The CBCT images were registered online to the planning CT images using the automatic algorithm followed by a fine manual adjustment. An action level of 3 mm, meaning that corrections were performed for translations exceeding 3 mm, was implemented in clinical treatments. Based on the acquired data, different correction action levels were simulated, and random RAIF errors, systematic RAIF errors and related margins before and after the treatments were determined for varying correction action levels. Results A total of 75 pairs of CBCT data sets were analyzed. The systematic and random setup errors based on skin-mark setup prior to treatment delivery were 2.1 mm and 1.8 mm in the lateral (LR, 3.1 mm and 2.3 mm in the superior-inferior (SI, and 2.3 mm and 2.0 mm in the anterior-posterior (AP directions. With the 3 mm correction action level, the systematic and random RAIF errors were 2.5 mm and 2.3 mm in the LR direction, 2.3 mm and 2.3 mm in the SI direction, and 2.3 mm and 2.2 mm in the AP direction after treatments delivery. Accordingly, the margins for correction action levels of 3 mm, 4 mm, 5 mm, 6 mm and no correction were 7.9 mm, 8.0 mm, 8.0 mm, 7.9 mm and 8.0 mm in the LR direction; 6.4 mm, 7.1 mm, 7.9 mm, 9.2 mm and 10.5 mm in the SI direction; 7.6 mm, 7.9 mm, 9.4 mm, 10

  13. Impact of residual and intrafractional errors on strategy of correction for image-guided accelerated partial breast irradiation

    International Nuclear Information System (INIS)

    Cai, Gang; Hu, Wei-Gang; Chen, Jia-Yi; Yu, Xiao-Li; Pan, Zi-Qiang; Yang, Zhao-Zhi; Guo, Xiao-Mao; Shao, Zhi-Min; Jiang, Guo-Liang

    2010-01-01

    The cone beam CT (CBCT) guided radiation can reduce the systematic and random setup errors as compared to the skin-mark setup. However, the residual and intrafractional (RAIF) errors are still unknown. The purpose of this paper is to investigate the magnitude of RAIF errors and correction action levels needed in cone beam computed tomography (CBCT) guided accelerated partial breast irradiation (APBI). Ten patients were enrolled in the prospective study of CBCT guided APBI. The postoperative tumor bed was irradiated with 38.5 Gy in 10 fractions over 5 days. Two cone-beam CT data sets were obtained with one before and one after the treatment delivery. The CBCT images were registered online to the planning CT images using the automatic algorithm followed by a fine manual adjustment. An action level of 3 mm, meaning that corrections were performed for translations exceeding 3 mm, was implemented in clinical treatments. Based on the acquired data, different correction action levels were simulated, and random RAIF errors, systematic RAIF errors and related margins before and after the treatments were determined for varying correction action levels. A total of 75 pairs of CBCT data sets were analyzed. The systematic and random setup errors based on skin-mark setup prior to treatment delivery were 2.1 mm and 1.8 mm in the lateral (LR), 3.1 mm and 2.3 mm in the superior-inferior (SI), and 2.3 mm and 2.0 mm in the anterior-posterior (AP) directions. With the 3 mm correction action level, the systematic and random RAIF errors were 2.5 mm and 2.3 mm in the LR direction, 2.3 mm and 2.3 mm in the SI direction, and 2.3 mm and 2.2 mm in the AP direction after treatments delivery. Accordingly, the margins for correction action levels of 3 mm, 4 mm, 5 mm, 6 mm and no correction were 7.9 mm, 8.0 mm, 8.0 mm, 7.9 mm and 8.0 mm in the LR direction; 6.4 mm, 7.1 mm, 7.9 mm, 9.2 mm and 10.5 mm in the SI direction; 7.6 mm, 7.9 mm, 9.4 mm, 10.1 mm and 12.7 mm in the AP direction

  14. Infinite dilution partial molar volumes of platinum(II) 2,4-pentanedionate in supercritical carbon dioxide.

    Science.gov (United States)

    Kong, Chang Yi; Siratori, Tomoya; Funazukuri, Toshitaka; Wang, Guosheng

    2014-10-03

    The effects of temperature and density on retention of platinum(II) 2,4-pentanedionate in supercritical fluid chromatography were investigated at temperatures of 308.15-343.15K and pressure range from 8 to 40MPa by the chromatographic impulse response method with curve fitting. The retention factors were utilized to derive the infinite dilution partial molar volumes of platinum(II) 2,4-pentanedionate in supercritical carbon dioxide. The determined partial molar volumes were small and positive at high pressures but exhibited very large and negative values in the highly compressible near critical region of carbon dioxide. Copyright © 2014 Elsevier B.V. All rights reserved.

  15. Intraperitoneal implant of recombinant encapsulated cells overexpressing alpha-L-iduronidase partially corrects visceral pathology in mucopolysaccharidosis type I mice.

    Science.gov (United States)

    Baldo, Guilherme; Mayer, Fabiana Quoos; Martinelli, Barbara; Meyer, Fabiola Schons; Burin, Maira; Meurer, Luise; Tavares, Angela Maria Vicente; Giugliani, Roberto; Matte, Ursula

    2012-08-01

    Mucopolysaccharidosis type I (MPS I) is characterized by deficiency of the enzyme alpha-L-iduronidase (IDUA) and storage of glycosaminoglycans (GAG) in several tissues. Current available treatments present limitations, thus the search for new therapies. Encapsulation of recombinant cells within polymeric structures combines gene and cell therapy and is a promising approach for treating MPS I. We produced alginate microcapsules containing baby hamster kidney (BHK) cells overexpressing IDUA and implanted these capsules in the peritoneum of MPS I mice. An increase in serum and tissue IDUA activity was observed at early time-points, as well as a reduction in GAG storage; however, correction in the long term was only partially achieved, with a drop in the IDUA activity being observed a few weeks after the implant. Analysis of the capsules obtained from the peritoneum revealed inflammation and a pericapsular fibrotic process, which could be responsible for the reduction in IDUA levels observed in the long term. In addition, treated mice developed antibodies against the enzyme. The results suggest that the encapsulation process is effective in the short term but improvements must be achieved in order to reduce the immune response and reach a stable correction.

  16. Correction

    CERN Multimedia

    2002-01-01

    Tile Calorimeter modules stored at CERN. The larger modules belong to the Barrel, whereas the smaller ones are for the two Extended Barrels. (The article was about the completion of the 64 modules for one of the latter.) The photo on the first page of the Bulletin n°26/2002, from 24 July 2002, illustrating the article «The ATLAS Tile Calorimeter gets into shape» was published with a wrong caption. We would like to apologise for this mistake and so publish it again with the correct caption.

  17. Theoretical study of the partial molar volume change associated with the pressure-induced structural transition of ubiquitin.

    Science.gov (United States)

    Imai, Takashi; Ohyama, Shusaku; Kovalenko, Andriy; Hirata, Fumio

    2007-09-01

    The partial molar volume (PMV) change associated with the pressure-induced structural transition of ubiquitin is analyzed by the three-dimensional reference interaction site model (3D-RISM) theory of molecular solvation. The theory predicts that the PMV decreases upon the structural transition, which is consistent with the experimental observation. The volume decomposition analysis demonstrates that the PMV reduction is primarily caused by the decrease in the volume of structural voids in the protein, which is partially canceled by the volume expansion due to the hydration effects. It is found from further analysis that the PMV reduction is ascribed substantially to the penetration of water molecules into a specific part of the protein. Based on the thermodynamic relation, this result implies that the water penetration causes the pressure-induced structural transition. It supports the water penetration model of pressure denaturation of proteins proposed earlier.

  18. Correction

    Directory of Open Access Journals (Sweden)

    2012-01-01

    Full Text Available Regarding Gorelik, G., & Shackelford, T.K. (2011. Human sexual conflict from molecules to culture. Evolutionary Psychology, 9, 564–587: The authors wish to correct an omission in citation to the existing literature. In the final paragraph on p. 570, we neglected to cite Burch and Gallup (2006 [Burch, R. L., & Gallup, G. G., Jr. (2006. The psychobiology of human semen. In S. M. Platek & T. K. Shackelford (Eds., Female infidelity and paternal uncertainty (pp. 141–172. New York: Cambridge University Press.]. Burch and Gallup (2006 reviewed the relevant literature on FSH and LH discussed in this paragraph, and should have been cited accordingly. In addition, Burch and Gallup (2006 should have been cited as the originators of the hypothesis regarding the role of FSH and LH in the semen of rapists. The authors apologize for this oversight.

  19. Correction

    CERN Multimedia

    2002-01-01

    The photo on the second page of the Bulletin n°48/2002, from 25 November 2002, illustrating the article «Spanish Visit to CERN» was published with a wrong caption. We would like to apologise for this mistake and so publish it again with the correct caption.   The Spanish delegation, accompanied by Spanish scientists at CERN, also visited the LHC superconducting magnet test hall (photo). From left to right: Felix Rodriguez Mateos of CERN LHC Division, Josep Piqué i Camps, Spanish Minister of Science and Technology, César Dopazo, Director-General of CIEMAT (Spanish Research Centre for Energy, Environment and Technology), Juan Antonio Rubio, ETT Division Leader at CERN, Manuel Aguilar-Benitez, Spanish Delegate to Council, Manuel Delfino, IT Division Leader at CERN, and Gonzalo León, Secretary-General of Scientific Policy to the Minister.

  20. Correction

    Directory of Open Access Journals (Sweden)

    2014-01-01

    Full Text Available Regarding Tagler, M. J., and Jeffers, H. M. (2013. Sex differences in attitudes toward partner infidelity. Evolutionary Psychology, 11, 821–832: The authors wish to correct values in the originally published manuscript. Specifically, incorrect 95% confidence intervals around the Cohen's d values were reported on page 826 of the manuscript where we reported the within-sex simple effects for the significant Participant Sex × Infidelity Type interaction (first paragraph, and for attitudes toward partner infidelity (second paragraph. Corrected values are presented in bold below. The authors would like to thank Dr. Bernard Beins at Ithaca College for bringing these errors to our attention. Men rated sexual infidelity significantly more distressing (M = 4.69, SD = 0.74 than they rated emotional infidelity (M = 4.32, SD = 0.92, F(1, 322 = 23.96, p < .001, d = 0.44, 95% CI [0.23, 0.65], but there was little difference between women's ratings of sexual (M = 4.80, SD = 0.48 and emotional infidelity (M = 4.76, SD = 0.57, F(1, 322 = 0.48, p = .29, d = 0.08, 95% CI [−0.10, 0.26]. As expected, men rated sexual infidelity (M = 1.44, SD = 0.70 more negatively than they rated emotional infidelity (M = 2.66, SD = 1.37, F(1, 322 = 120.00, p < .001, d = 1.12, 95% CI [0.85, 1.39]. Although women also rated sexual infidelity (M = 1.40, SD = 0.62 more negatively than they rated emotional infidelity (M = 2.09, SD = 1.10, this difference was not as large and thus in the evolutionary theory supportive direction, F(1, 322 = 72.03, p < .001, d = 0.77, 95% CI [0.60, 0.94].

  1. Volume of eggs in the clutches of Grass snake Natrix natrix and Dice snake N. tessellata: error correction

    Directory of Open Access Journals (Sweden)

    Klenina Anastasiya Aleksandrovna

    2015-12-01

    Full Text Available The authors have made a mistake in calculating the volume of eggs in the clutches of snake family Natrix. In this article we correct the error. As a result, it was revealed, that the volume of eggs positively correlates with a female length and its mass, as well as with the quantity of eggs in the clutches. There is a positive correlation between the characteristics of newborn snakes (length and mass and the volume of eggs, from which they hatched.

  2. Thermodynamic study of (heptane + amine) mixtures. II. Excess and partial molar volumes at 298.15 K

    International Nuclear Information System (INIS)

    Lepori, Luciano; Gianni, Paolo; Spanedda, Andrea; Matteoli, Enrico

    2011-01-01

    Research highlights: → Excess and partial molar volumes of primary (amines + heptane) mixtures. → Excess volumes are positive for small size amines and decrease as the size increases. → Group contributions to predict the partial molar volumes of amines in heptane. → The void volume is larger for branched than for linear amines in heptane. - Abstract: Excess molar volumes V E at 298.15 K were determined by means of a vibrating tube densimeter for binary mixtures of heptane + primary n-alkyl (C 3 to C 10 ) and branched amines (iso-propyl-, iso-, sec-, and tert-butyl-, iso-, tert-pentyl-, and pentan-3-amine) in the whole composition range. The apparent molar volumes of solid dodecyl- and tetradecylamine in heptane dilute solution were also determined. The V E values were found positive for mixtures involving C 3 to C 8 linear amines, with V E decreasing with chain lengthening. Heptane + nonyl and decylamine showed s-shaped, markedly asymmetric, curves. Mixtures with branched C 3 to C 5 amines displayed positive V E 's larger than those observed in the mixtures of the corresponding linear isomers. Partial molar volumes V o at infinite dilution in heptane were evaluated for the examined amines and compared with those of alkanes and alkanols taken from the literature. An additivity scheme, based on the intrinsic volume approach, was applied to estimate group (CH 3 , CH 2 , CH, C, NH 2 , and OH) contributions to V o . The effect of branching on V o and the limiting slope of the apparent excess molar volumes were evaluated and discussed in terms of solute-solvent and solute-solute interactions.

  3. Concentration dependence of the partial volume, viscosity, and electric conductivity of solutions of lithium salts in aliphatic alcohols

    International Nuclear Information System (INIS)

    Eliseeva, O.V.; Golubev, V.V.

    2003-01-01

    Concentration dependence of partial volumes, electric conductivity and viscosity of lithium nitrate and chloride solutions in methanol, propanol, isopropanol, butanol, isobutanol, pentanol and isopentanol at 298.15 K were studied by the methods of densimetry, conductometry and viscosimetry. Structural specific features of the solutions studied are discussed on the basis of the calculated volumetric characteristics of the substance dissolved and solvent [ru

  4. Estimating the two-particle $K$-matrix for multiple partial waves and decay channels from finite-volume energies

    DEFF Research Database (Denmark)

    Morningstar, Colin; Bulava, John; Singha, Bijit

    2017-01-01

    An implementation of estimating the two-to-two $K$-matrix from finite-volume energies based on the L\\"uscher formalism and involving a Hermitian matrix known as the "box matrix" is described. The method includes higher partial waves and multiple decay channels. Two fitting procedures for estimating...

  5. A 2 × 2 taxonomy of multilevel latent contextual models: accuracy-bias trade-offs in full and partial error correction models.

    Science.gov (United States)

    Lüdtke, Oliver; Marsh, Herbert W; Robitzsch, Alexander; Trautwein, Ulrich

    2011-12-01

    In multilevel modeling, group-level variables (L2) for assessing contextual effects are frequently generated by aggregating variables from a lower level (L1). A major problem of contextual analyses in the social sciences is that there is no error-free measurement of constructs. In the present article, 2 types of error occurring in multilevel data when estimating contextual effects are distinguished: unreliability that is due to measurement error and unreliability that is due to sampling error. The fact that studies may or may not correct for these 2 types of error can be translated into a 2 × 2 taxonomy of multilevel latent contextual models comprising 4 approaches: an uncorrected approach, partial correction approaches correcting for either measurement or sampling error (but not both), and a full correction approach that adjusts for both sources of error. It is shown mathematically and with simulated data that the uncorrected and partial correction approaches can result in substantially biased estimates of contextual effects, depending on the number of L1 individuals per group, the number of groups, the intraclass correlation, the number of indicators, and the size of the factor loadings. However, the simulation study also shows that partial correction approaches can outperform full correction approaches when the data provide only limited information in terms of the L2 construct (i.e., small number of groups, low intraclass correlation). A real-data application from educational psychology is used to illustrate the different approaches.

  6. M-area hazardous waste management facility groundwater monitoring and corrective-action report, First quarter 1995, Volume 1

    International Nuclear Information System (INIS)

    1995-05-01

    This report, in three volumes, describes the ground water monitoring and c corrective-action program at the M-Area Hazardous Waste Management Facility (HWMF) at the Savannah River Site (SRS) during the fourth quarter 1994 and first quarter 1995. Concise description of the program and considerable data documenting the monitoring and remedial activities are included in the document. This is Volume 1 covering the following topics: sampling and results; hydrogeologic assessment; water quality assessment; effectiveness of the corrective-action program; corrective-action system operation and performance; monitoring and corrective-action program assessment; proposed monitoring and corrective-action program modifications. Also included are the following appendicies: A-standards; B-flagging criteria; C-figures; D-monitoring results tables; E-data quality/usability assessment

  7. Partial molar volumes of some drug and pro-drug substances in 1-octanol at T = 298.15 K

    International Nuclear Information System (INIS)

    Manin, Alex N.; Shmukler, Liudmila E.; Safonova, Liubov P.; Perlovich, German L.

    2010-01-01

    The article deals with measuring the densities of phenol, acetanilide, benzamide, benzoic acid, phenacetin, i-(acetylamino)-benzoic acid, i-hydroxy-benzamide, and i-acetaminophen (where i = 1, 2, 3) in 1-octanol in the wide concentration interval at T = 298.15 K. It also concerns the evaluation of apparent molar volumes and partial molar volumes at infinite dilution, V 2 0 -bar as well as comparative analysis of the free volumes per molecule in the octanolic solutions, V 2 free , and in the crystal lattices, V 2 free (cr), from the nature and position of the substitutes. Also described is the evaluation of the increments of V 2 0 -bar andV 2 free for the unsubstituted molecules and isomers and the methods to obtain partial molar volumes for various functional groups at infinite dilution in 1-octanol at T = 298.15 K. Also considered is the limiting partial molar volume of the solutes in terms of the scaled particle theory.

  8. Partial molar volumes of some drug and pro-drug substances in 1-octanol at T = 298.15 K

    Energy Technology Data Exchange (ETDEWEB)

    Manin, Alex N.; Shmukler, Liudmila E.; Safonova, Liubov P. [Institute of Solution Chemistry, Russian Academy of Sciences, 153045 Ivanovo (Russian Federation); Perlovich, German L., E-mail: glp@isc-ras.r [Institute of Solution Chemistry, Russian Academy of Sciences, 153045 Ivanovo (Russian Federation)

    2010-03-15

    The article deals with measuring the densities of phenol, acetanilide, benzamide, benzoic acid, phenacetin, i-(acetylamino)-benzoic acid, i-hydroxy-benzamide, and i-acetaminophen (where i = 1, 2, 3) in 1-octanol in the wide concentration interval at T = 298.15 K. It also concerns the evaluation of apparent molar volumes and partial molar volumes at infinite dilution, V{sub 2}{sup 0}-bar as well as comparative analysis of the free volumes per molecule in the octanolic solutions, V{sub 2}{sup free}, and in the crystal lattices, V{sub 2}{sup free} (cr), from the nature and position of the substitutes. Also described is the evaluation of the increments of V{sub 2}{sup 0}-bar andV{sub 2}{sup free} for the unsubstituted molecules and isomers and the methods to obtain partial molar volumes for various functional groups at infinite dilution in 1-octanol at T = 298.15 K. Also considered is the limiting partial molar volume of the solutes in terms of the scaled particle theory.

  9. Syringe calibration factors and volume correction factors for the NPL secondary standard radionuclide calibrator

    CERN Document Server

    Tyler, D K

    2002-01-01

    The activity assay of a radiopharmaceutical administration to a patient is normally achieved via the use of a radionuclide calibrator. Because of the different geometries and elemental compositions between plastic syringes and glass vials, the calibration factors for syringes may well be significantly different from those for the glass containers. The magnitude of these differences depends on the energies of the emitted photons. For some radionuclides variations have been observed of 70 %, it is therefore important to recalibrate for syringes or use syringe calibration factors. Calibration factors and volume correction factors have been derived for the NPL secondary standard radionuclide calibrator, for a variety of commonly used syringes and needles, for the most commonly used medical radionuclide.

  10. In-Situ Systematic Error Correction for Digital Volume Correlation Using a Reference Sample

    KAUST Repository

    Wang, B.

    2017-11-27

    The self-heating effect of a laboratory X-ray computed tomography (CT) scanner causes slight change in its imaging geometry, which induces translation and dilatation (i.e., artificial displacement and strain) in reconstructed volume images recorded at different times. To realize high-accuracy internal full-field deformation measurements using digital volume correlation (DVC), these artificial displacements and strains associated with unstable CT imaging must be eliminated. In this work, an effective and easily implemented reference sample compensation (RSC) method is proposed for in-situ systematic error correction in DVC. The proposed method utilizes a stationary reference sample, which is placed beside the test sample to record the artificial displacement fields caused by the self-heating effect of CT scanners. The detected displacement fields are then fitted by a parametric polynomial model, which is used to remove the unwanted artificial deformations in the test sample. Rescan tests of a stationary sample and real uniaxial compression tests performed on copper foam specimens demonstrate the accuracy, efficacy, and practicality of the presented RSC method.

  11. In-Situ Systematic Error Correction for Digital Volume Correlation Using a Reference Sample

    KAUST Repository

    Wang, B.; Pan, B.; Lubineau, Gilles

    2017-01-01

    The self-heating effect of a laboratory X-ray computed tomography (CT) scanner causes slight change in its imaging geometry, which induces translation and dilatation (i.e., artificial displacement and strain) in reconstructed volume images recorded at different times. To realize high-accuracy internal full-field deformation measurements using digital volume correlation (DVC), these artificial displacements and strains associated with unstable CT imaging must be eliminated. In this work, an effective and easily implemented reference sample compensation (RSC) method is proposed for in-situ systematic error correction in DVC. The proposed method utilizes a stationary reference sample, which is placed beside the test sample to record the artificial displacement fields caused by the self-heating effect of CT scanners. The detected displacement fields are then fitted by a parametric polynomial model, which is used to remove the unwanted artificial deformations in the test sample. Rescan tests of a stationary sample and real uniaxial compression tests performed on copper foam specimens demonstrate the accuracy, efficacy, and practicality of the presented RSC method.

  12. A Review of the Effect of Injected Dextranomer/Hyaluronic Acid Copolymer Volume on Reflux Correction Following Endoscopic Injection

    Directory of Open Access Journals (Sweden)

    Sumit Dave

    2008-01-01

    Full Text Available The current literature suggests that multiple variables affect vesicoureteric reflux (VUR resolution rates following dextranomer/hyaluronic acid copolymer (Dx/HA injection. This article reviews the evidence pertaining to the effect of injected Dx/HA volume on success rates following endoscopic correction. Lack of prospective studies which use injected volume as a continuous variable coupled with a nonstandardized injection technique and endpoint hinders the ability to reach a definite conclusion.

  13. Multi-tissue partial volume quantification in multi-contrast MRI using an optimised spectral unmixing approach.

    Science.gov (United States)

    Collewet, Guylaine; Moussaoui, Saïd; Deligny, Cécile; Lucas, Tiphaine; Idier, Jérôme

    2018-06-01

    Multi-tissue partial volume estimation in MRI images is investigated with a viewpoint related to spectral unmixing as used in hyperspectral imaging. The main contribution of this paper is twofold. It firstly proposes a theoretical analysis of the statistical optimality conditions of the proportion estimation problem, which in the context of multi-contrast MRI data acquisition allows to appropriately set the imaging sequence parameters. Secondly, an efficient proportion quantification algorithm based on the minimisation of a penalised least-square criterion incorporating a regularity constraint on the spatial distribution of the proportions is proposed. Furthermore, the resulting developments are discussed using empirical simulations. The practical usefulness of the spectral unmixing approach for partial volume quantification in MRI is illustrated through an application to food analysis on the proving of a Danish pastry. Copyright © 2018 Elsevier Inc. All rights reserved.

  14. PVR: Patch-to-Volume Reconstruction for Large Area Motion Correction of Fetal MRI.

    Science.gov (United States)

    Alansary, Amir; Rajchl, Martin; McDonagh, Steven G; Murgasova, Maria; Damodaram, Mellisa; Lloyd, David F A; Davidson, Alice; Rutherford, Mary; Hajnal, Joseph V; Rueckert, Daniel; Kainz, Bernhard

    2017-10-01

    In this paper, we present a novel method for the correction of motion artifacts that are present in fetal magnetic resonance imaging (MRI) scans of the whole uterus. Contrary to current slice-to-volume registration (SVR) methods, requiring an inflexible anatomical enclosure of a single investigated organ, the proposed patch-to-volume reconstruction (PVR) approach is able to reconstruct a large field of view of non-rigidly deforming structures. It relaxes rigid motion assumptions by introducing a specific amount of redundant information that is exploited with parallelized patchwise optimization, super-resolution, and automatic outlier rejection. We further describe and provide an efficient parallel implementation of PVR allowing its execution within reasonable time on commercially available graphics processing units, enabling its use in the clinical practice. We evaluate PVR's computational overhead compared with standard methods and observe improved reconstruction accuracy in the presence of affine motion artifacts compared with conventional SVR in synthetic experiments. Furthermore, we have evaluated our method qualitatively and quantitatively on real fetal MRI data subject to maternal breathing and sudden fetal movements. We evaluate peak-signal-to-noise ratio, structural similarity index, and cross correlation with respect to the originally acquired data and provide a method for visual inspection of reconstruction uncertainty. We further evaluate the distance error for selected anatomical landmarks in the fetal head, as well as calculating the mean and maximum displacements resulting from automatic non-rigid registration to a motion-free ground truth image. These experiments demonstrate a successful application of PVR motion compensation to the whole fetal body, uterus, and placenta.

  15. Evaluation of the partial volume effect in the activity quantification in PET/CT images; Avaliacao do efeito de volume parcial na quantificacao de atividade em imagens de PET/CT

    Energy Technology Data Exchange (ETDEWEB)

    Krempser, Alexandre R., E-mail: krempser@peb.ufrj.br [Coordenacao dos Programas de Pos-Graduacao de Engenharia (COPPE/UFRJ), RJ (Brazil). Instituto Alberto Luiz Coimbra. Programa de Engenharia Biomedica; Oliveira, Silvia M. Velasques de [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil); Almeida, Sergio A. de [Hospital Samaritano, Rio de Janeiro, RJ (Brazil). Centro de Imagens PET/CT

    2012-08-15

    The aim of this work was to evaluate the influence of partial volume effect (PVE) in the quantification of activity in images of a PET-CT scanner and its ability to identify lesions. Recovery coefficients were calculated using a phantom containing 12 cylinders with diameters between 4 and 30 mm and a National Electrical Manufactures Association scattering phantom, both fillable with known concentrations of {sup 18}F. The images were acquired for acquisition time of 3 and 5 minutes, and cylinder to background ratio of n=8:1 and n=4:1. The recovery coefficients were calculated between 0.01 and 0.91 depending on the diameter. Significant variations were not found in function of image acquisition parameters. Errors in the activity quantification above 70% were found for cylinders with diameters smaller than 10 mm. The cylinders with diameters smaller than 8 mm were not identified in the images. The phantoms were adequate for PVE evaluation in the PET/CT images. The PVE had the greatest impact on the cylinders with diameters of 6 and 4 mm. It's necessary to use partial volume correction techniques in the images in order to increase the quantitative accuracy of the studied equipment. (author)

  16. Partial molar volumes of (acetonitrile + water) mixtures over the temperature range (273.15 to 318.15) K

    International Nuclear Information System (INIS)

    Yeow, Y. Leong; Leong, Yee-Kwong

    2007-01-01

    Isothermal molar volume data of (acetonitrile + water) mixtures, between T = 273.15 K and T = 318.15 K, extracted from different sources are combined and treated as a single set to even out minor differences between sources and to increase the number of data points for each temperature. Tikhonov regularization is applied to compute the isothermal first and second derivatives of these data with respect to molar composition. For the reference temperature of 298.15 K, this computation is extended to the third derivative. Generalized Cross Validation is used to guide the selection of the regularization parameter that keeps noise amplification under control. The resulting first derivatives are used to construct the partial molar volume curves which are then checked against published results. Properties of the partial molar volumes are analysed by examining their derivatives. Finally the general shape of the second derivative curve of molar volume is explained qualitatively in terms of tripartite segmentation of the molar composition interval but quantitative comparisons are required to confirm this explanation

  17. Partial Molar Volumes of 15-Crown-5 Ether in Mixtures of N,N-Dimethylformamide with Water.

    Science.gov (United States)

    Tyczyńska, Magdalena; Jóźwiak, Małgorzata

    2014-01-01

    The density of 15-crown-5 ether (15C5) solutions in the mixtures of N,N -dimethylformamide (DMF) and water (H 2 O) was measured within the temperature range 293.15-308.15 K using an Anton Paar oscillatory U-tube densimeter. The results were used to calculate the apparent molar volumes ( V Φ ) of 15C5 in the mixtures of DMF + H 2 O over the whole concentration range. Using the apparent molar volumes and Redlich and Mayer equation, the standard partial molar volumes of 15-crown-5 were calculated at infinite dilution ([Formula: see text]). The limiting apparent molar expansibilities ( α ) were also calculated. The data are discussed from the point of view of the effect of concentration changes on interactions in solution.

  18. Fabrication of a Customized Ball Abutment to Correct a Nonparallel Implant Abutment for a Mandibular Implant-Supported Removable Partial Prosthesis: A Case Report

    Directory of Open Access Journals (Sweden)

    Hossein Dasht

    2017-12-01

    Full Text Available Introduction: While using an implant-supported removable partial prosthesis, the implant abutments should be parallel to one another along the path of insertion. If the implants and their attachments are placed vertically on a similar occlusal plane, not only is the retention improved, the prosthesis will also be maintained for a longer period. Case Report: A 65-year-old male patient referred to the School of Dentistry in Mashhad, Iran with complaints of discomfort with the removable partial dentures for his lower mandible. Due to the lack of parallelism in the supporting implants, prefabricated ball abutment could not be used. As a result, a customized ball abutment was fabricated in order to correct the non-parallelism of the implants. Conclusion: Using UCLA abutments could be a cost-efficient approach for the correction of misaligned implant abutments in implant-supported overdentures.

  19. Estimating the two-particle K-matrix for multiple partial waves and decay channels from finite-volume energies

    Directory of Open Access Journals (Sweden)

    Colin Morningstar

    2017-11-01

    Full Text Available An implementation of estimating the two-to-two K-matrix from finite-volume energies based on the Lüscher formalism and involving a Hermitian matrix known as the “box matrix” is described. The method includes higher partial waves and multiple decay channels. Two fitting procedures for estimating the K-matrix parameters, which properly incorporate all statistical covariances, are discussed. Formulas and software for handling total spins up to S=2 and orbital angular momenta up to L=6 are obtained for total momenta in several directions. First tests involving ρ-meson decay to two pions include the L=3 and L=5 partial waves, and the contributions from these higher waves are found to be negligible in the elastic energy range.

  20. PET imaging of thin objects: measuring the effects of positron range and partial-volume averaging in the leaf of Nicotiana tabacum

    Energy Technology Data Exchange (ETDEWEB)

    Alexoff, David L., E-mail: alexoff@bnl.gov; Dewey, Stephen L.; Vaska, Paul; Krishnamoorthy, Srilalan; Ferrieri, Richard; Schueller, Michael; Schlyer, David J.; Fowler, Joanna S.

    2011-02-15

    Introduction: PET imaging in plants is receiving increased interest as a new strategy to measure plant responses to environmental stimuli and as a tool for phenotyping genetically engineered plants. PET imaging in plants, however, poses new challenges. In particular, the leaves of most plants are so thin that a large fraction of positrons emitted from PET isotopes ({sup 18}F, {sup 11}C, {sup 13}N) escape while even state-of-the-art PET cameras have significant partial-volume errors for such thin objects. Although these limitations are acknowledged by researchers, little data have been published on them. Methods: Here we measured the magnitude and distribution of escaping positrons from the leaf of Nicotiana tabacum for the radionuclides {sup 18}F, {sup 11}C and {sup 13}N using a commercial small-animal PET scanner. Imaging results were compared to radionuclide concentrations measured from dissection and counting and to a Monte Carlo simulation using GATE (Geant4 Application for Tomographic Emission). Results: Simulated and experimentally determined escape fractions were consistent. The fractions of positrons (mean{+-}S.D.) escaping the leaf parenchyma were measured to be 59{+-}1.1%, 64{+-}4.4% and 67{+-}1.9% for {sup 18}F, {sup 11}C and {sup 13}N, respectively. Escape fractions were lower in thicker leaf areas like the midrib. Partial-volume averaging underestimated activity concentrations in the leaf blade by a factor of 10 to 15. Conclusions: The foregoing effects combine to yield PET images whose contrast does not reflect the actual activity concentrations. These errors can be largely corrected by integrating activity along the PET axis perpendicular to the leaf surface, including detection of escaped positrons, and calculating concentration using a measured leaf thickness.

  1. Partial Molar Volumes of Air-Component Gases in Several Liquid n-Alkanes and 1-Alkanols at 313.15 K

    Czech Academy of Sciences Publication Activity Database

    Izák, Pavel; Cibulka, I.; Heintz, A.

    1995-01-01

    Roč. 109, č. 2 (1995), s. 227-234 ISSN 0378-3812 Keywords : data density * partial molar volume * gas -liquid mixture Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 1.024, year: 1995

  2. Target volume definition for external beam partial breast radiotherapy: Clinical, pathological and technical studies informing current approaches

    International Nuclear Information System (INIS)

    Kirby, Anna M.; Coles, Charlotte E.; Yarnold, John R.

    2010-01-01

    Partial breast irradiation (PBI) is currently under investigation in several phase III trials and, following a recent consensus statement, its use off-study may increase despite ongoing uncertainty regarding optimal target volume definition. We review the clinical, pathological and technical evidence for target volume definition in external beam partial breast irradiation (EB-PBI). The optimal method of tumour bed (TB) delineation requires X-ray CT imaging of implanted excision cavity wall markers. The definition of clinical target volume (CTV) as TB plus concentric 15 mm margins is based on the anatomical distribution of multifocal and multicentric disease around the primary tumour in mastectomy specimens, and the clinical locations of local tumour relapse (LR) after breast conservation surgery. If the majority of LR originate from foci of residual invasive and/or intraduct disease in the vicinity of the TB after complete microscopic resection, CTV margin logically takes account of the position of primary tumour within the surgical resection specimen. The uncertain significance of independent primary tumours as sources of preventable LR, and of wound healing responses in stimulating LR, increases the difficulties in defining optimal CTV. These uncertainties may resolve after long-term follow-up of current PBI trials. By contrast, a commonly used 10 mm clinical to planning target volume (PTV) margin has a stronger evidence base, although departmental set-up errors need to be confirmed locally. A CTV-PTV margin >10 mm may be required in women with larger breasts and/or large seromas, whilst the role of image-guided radiotherapy with or without TB markers in reducing CTV-PTV margins needs to be explored.

  3. Recent trends in operator theory and partial differential equations the Roland Duduchava anniversary volume

    CERN Document Server

    Natroshvili, David; Shargorodsky, Eugene; Wendland, Wolfgang

    2017-01-01

    This volume is dedicated to the eminent Georgian mathematician Roland Duduchava on the occasion of his 70th birthday. It presents recent results on Toeplitz, Wiener-Hopf, and pseudodifferential operators, boundary value problems, operator theory, approximation theory, and reflects the broad spectrum of Roland Duduchava's research. The book is addressed to a wide audience of pure and applied mathematicians.

  4. A novel method for the angiographic estimation of the percentage of spleen volume embolized during partial splenic embolization

    International Nuclear Information System (INIS)

    Ou, Ming-Ching; Chuang, Ming-Tsung; Lin, Xi-Zhang; Tsai, Hong-Ming; Chen, Shu-Yuan; Liu, Yi-Sheng

    2013-01-01

    Purpose: To evaluate the efficacy of estimating the volume of spleen embolized in partial splenic embolization (PSE) by measuring the diameters of the splenic artery and its branches. Materials and methods: A total of 43 liver cirrhosis patients (mean age, 62.19 ± 9.65 years) with thrombocytopenia were included. Among these, 24 patients underwent a follow-up CT scan which showed a correlation between angiographic estimation and measured embolized splenic volume. Estimated splenic embolization volume was calculated by a method based on diameters of the splenic artery and its branches. The diameters of each of the splenic arteries and branches were measured via 2D angiographic images. Embolization was performed with gelatin sponges. Patients underwent follow-up with serial measurement of blood counts and liver function tests. The actual volume of embolized spleen was determined by computed tomography (CT) measuring the volumes of embolized and non-embolized spleen two months after PSE. Results: PSE was performed without immediate major complications. The mean WBC count significantly increased from 3.81 ± 1.69 × 10 3 /mm 3 before PSE to 8.56 ± 3.14 × 10 3 /mm 3 at 1 week after PSE (P < 0.001). Mean platelet count significantly increased from 62.00 ± 22.62 × 10 3 /mm 3 before PSE to 95.40 ± 46.29 × 10 3 /mm 3 1 week after PSE (P < 0.001). The measured embolization ratio was positively correlated with estimated embolization ratio (Spearman's rho [ρ] = 0.687, P < 0.001). The mean difference between the actual embolization ratio and the estimated embolization ratio was 16.16 ± 8.96%. Conclusions: The method provides a simple method to quantitatively estimate embolized splenic volume with a correlation of measured embolization ratio to estimated embolization ratio of Spearman's ρ = 0.687

  5. Evaluation of different set-up error corrections on dose-volume metrics in prostate IMRT using CBCT images

    International Nuclear Information System (INIS)

    Hirose, Yoshinori; Tomita, Tsuneyuki; Kitsuda, Kenji; Notogawa, Takuya; Miki, Katsuhito; Nakamura, Mitsuhiro; Nakamura, Kiyonao; Ishigaki, Takashi

    2014-01-01

    We investigated the effect of different set-up error corrections on dose-volume metrics in intensity-modulated radiotherapy (IMRT) for prostate cancer under different planning target volume (PTV) margin settings using cone-beam computed tomography (CBCT) images. A total of 30 consecutive patients who underwent IMRT for prostate cancer were retrospectively analysed, and 7-14 CBCT datasets were acquired per patient. Interfractional variations in dose-volume metrics were evaluated under six different set-up error corrections, including tattoo, bony anatomy, and four different target matching groups. Set-up errors were incorporated into planning the isocenter position, and dose distributions were recalculated on CBCT images. These processes were repeated under two different PTV margin settings. In the on-line bony anatomy matching groups, systematic error (Σ) was 0.3 mm, 1.4 mm, and 0.3 mm in the left-right, anterior-posterior (AP), and superior-inferior directions, respectively. Σ in three successive off-line target matchings was finally comparable with that in the on-line bony anatomy matching in the AP direction. Although doses to the rectum and bladder wall were reduced for a small PTV margin, averaged reductions in the volume receiving 100% of the prescription dose from planning were within 2.5% under all PTV margin settings for all correction groups, with the exception of the tattoo set-up error correction only (≥ 5.0%). Analysis of variance showed no significant difference between on-line bony anatomy matching and target matching. While variations between the planned and delivered doses were smallest when target matching was applied, the use of bony anatomy matching still ensured the planned doses. (author)

  6. Classifying Acute Respiratory Distress Syndrome Severity: Correcting the Arterial Oxygen Partial Pressure to Fractional Inspired Oxygen at Altitude.

    Science.gov (United States)

    Pérez-Padilla, Rogelio; Hernández-Cárdenas, Carmen Margarita; Lugo-Goytia, Gustavo

    2016-01-01

    In the well-known Berlin definition of acute respiratory distress syndrome (ARDS), there is a recommended adjustment for arterial oxygen partial pressure to fractional inspired oxygen (PaO2/FIO2) at altitude, but without a reference as to how it was derived.

  7. Super-resolution reconstruction in frequency, image, and wavelet domains to reduce through-plane partial voluming in MRI

    Energy Technology Data Exchange (ETDEWEB)

    Gholipour, Ali, E-mail: ali.gholipour@childrens.harvard.edu; Afacan, Onur; Scherrer, Benoit; Prabhu, Sanjay P.; Warfield, Simon K. [Department of Radiology, Boston Children’s Hospital, Boston, Massachusetts 02115 and Harvard Medical School, Boston, Massachusetts 02115 (United States); Aganj, Iman [Radiology Department, Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Boston, Massachusetts 02129 and Harvard Medical School, Boston, Massachusetts 02115 (United States); Sahin, Mustafa [Department of Neurology, Boston Children’s Hospital, Boston, Massachusetts 02115 and Harvard Medical School, Boston, Massachusetts 02115 (United States)

    2015-12-15

    Purpose: To compare and evaluate the use of super-resolution reconstruction (SRR), in frequency, image, and wavelet domains, to reduce through-plane partial voluming effects in magnetic resonance imaging. Methods: The reconstruction of an isotropic high-resolution image from multiple thick-slice scans has been investigated through techniques in frequency, image, and wavelet domains. Experiments were carried out with thick-slice T2-weighted fast spin echo sequence on the Academic College of Radiology MRI phantom, where the reconstructed images were compared to a reference high-resolution scan using peak signal-to-noise ratio (PSNR), structural similarity image metric (SSIM), mutual information (MI), and the mean absolute error (MAE) of image intensity profiles. The application of super-resolution reconstruction was then examined in retrospective processing of clinical neuroimages of ten pediatric patients with tuberous sclerosis complex (TSC) to reduce through-plane partial voluming for improved 3D delineation and visualization of thin radial bands of white matter abnormalities. Results: Quantitative evaluation results show improvements in all evaluation metrics through super-resolution reconstruction in the frequency, image, and wavelet domains, with the highest values obtained from SRR in the image domain. The metric values for image-domain SRR versus the original axial, coronal, and sagittal images were PSNR = 32.26 vs 32.22, 32.16, 30.65; SSIM = 0.931 vs 0.922, 0.924, 0.918; MI = 0.871 vs 0.842, 0.844, 0.831; and MAE = 5.38 vs 7.34, 7.06, 6.19. All similarity metrics showed high correlations with expert ranking of image resolution with MI showing the highest correlation at 0.943. Qualitative assessment of the neuroimages of ten TSC patients through in-plane and out-of-plane visualization of structures showed the extent of partial voluming effect in a real clinical scenario and its reduction using SRR. Blinded expert evaluation of image resolution in

  8. Super-resolution reconstruction in frequency, image, and wavelet domains to reduce through-plane partial voluming in MRI

    International Nuclear Information System (INIS)

    Gholipour, Ali; Afacan, Onur; Scherrer, Benoit; Prabhu, Sanjay P.; Warfield, Simon K.; Aganj, Iman; Sahin, Mustafa

    2015-01-01

    Purpose: To compare and evaluate the use of super-resolution reconstruction (SRR), in frequency, image, and wavelet domains, to reduce through-plane partial voluming effects in magnetic resonance imaging. Methods: The reconstruction of an isotropic high-resolution image from multiple thick-slice scans has been investigated through techniques in frequency, image, and wavelet domains. Experiments were carried out with thick-slice T2-weighted fast spin echo sequence on the Academic College of Radiology MRI phantom, where the reconstructed images were compared to a reference high-resolution scan using peak signal-to-noise ratio (PSNR), structural similarity image metric (SSIM), mutual information (MI), and the mean absolute error (MAE) of image intensity profiles. The application of super-resolution reconstruction was then examined in retrospective processing of clinical neuroimages of ten pediatric patients with tuberous sclerosis complex (TSC) to reduce through-plane partial voluming for improved 3D delineation and visualization of thin radial bands of white matter abnormalities. Results: Quantitative evaluation results show improvements in all evaluation metrics through super-resolution reconstruction in the frequency, image, and wavelet domains, with the highest values obtained from SRR in the image domain. The metric values for image-domain SRR versus the original axial, coronal, and sagittal images were PSNR = 32.26 vs 32.22, 32.16, 30.65; SSIM = 0.931 vs 0.922, 0.924, 0.918; MI = 0.871 vs 0.842, 0.844, 0.831; and MAE = 5.38 vs 7.34, 7.06, 6.19. All similarity metrics showed high correlations with expert ranking of image resolution with MI showing the highest correlation at 0.943. Qualitative assessment of the neuroimages of ten TSC patients through in-plane and out-of-plane visualization of structures showed the extent of partial voluming effect in a real clinical scenario and its reduction using SRR. Blinded expert evaluation of image resolution in

  9. Volume corrections factors in the measurement of 99mTc and 123I activities in radionuclide calibrators

    International Nuclear Information System (INIS)

    Correia, Amanda Ribeiro; Rezende, Eduarda Alexandre; Iwahara, Akira; Oliveira, Antonio Eduardo de; Oliveira, Estela Maria de; Tauhata, Luiz; Chaves, Taina Olivieri

    2012-01-01

    To determine correction factors for the variation in volume of radiopharmaceuticals in containers of different geometries, comparing the influence of such factors on the determination of 99m Tc and 123 I activity with two types of calibrators - one with ionization chamber and another with Geiger-Mueller (G-M) detector -; and to evaluate calibrators performance in the measurement of 99m Tc and 1 '2 3 I activities. Materials and Methods: Eight calibrators, 10R glass vials, 3 and 5 mL plastic syringes and 99m Tc and 123 I solutions were utilized. The correction factors were determined with basis on practical measurements of the variation in the calibrators' response according to the volume of radionuclide solution in the glass vials. The performance was evaluated according to the acceptance criterion of +- 10% accuracy required by the Brazilian standard. Results: The variation of the calibrators' response according to the variation in radionuclide volume was reasonably greater in the calibrator with G-M detector. It was also greater for 123 I than for 99m Tc. Conclusion: The results confirm that the calibrators' response depends on the radionuclide volume contained in the vials. Such dependence is more critical for the calibrators equipped with G-M detector and for 123 I as compared with 99m Tc. (author)

  10. Influence of Co-57 and CT Transmission Measurements on the Quantification Accuracy and Partial Volume Effect of a Small Animal PET Scanner.

    Science.gov (United States)

    Mannheim, Julia G; Schmid, Andreas M; Pichler, Bernd J

    2017-12-01

    Non-invasive in vivo positron emission tomography (PET) provides high detection sensitivity in the nano- to picomolar range and in addition to other advantages, the possibility to absolutely quantify the acquired data. The present study focuses on the comparison of transmission data acquired with an X-ray computed tomography (CT) scanner or a Co-57 source for the Inveon small animal PET scanner (Siemens Healthcare, Knoxville, TN, USA), as well as determines their influences on the quantification accuracy and partial volume effect (PVE). A special focus included the impact of the performed calibration on the quantification accuracy. Phantom measurements were carried out to determine the quantification accuracy, the influence of the object size on the quantification, and the PVE for different sphere sizes, along the field of view and for different contrast ratios. An influence of the emission activity on the Co-57 transmission measurements was discovered (deviations up to 24.06 % measured to true activity), whereas no influence of the emission activity on the CT attenuation correction was identified (deviations influenced by the applied calibration factor and by the object size. The PVE demonstrated a dependency on the sphere size, the position within the field of view, the reconstruction and correction algorithms and the count statistics. Depending on the reconstruction algorithm, only ∼30-40 % of the true activity within a small sphere could be resolved. The iterative 3D reconstruction algorithms uncovered substantially increased recovery values compared to the analytical and 2D iterative reconstruction algorithms (up to 70.46 % and 80.82 % recovery for the smallest and largest sphere using iterative 3D reconstruction algorithms). The transmission measurement (CT or Co-57 source) to correct for attenuation did not severely influence the PVE. The analysis of the quantification accuracy and the PVE revealed an influence of the object size, the reconstruction

  11. Interobserver variations of target volume delineation and its impact on irradiated volume in accelerated partial breast irradiation with intraoperative interstitial breast implant

    Directory of Open Access Journals (Sweden)

    Ritu Raj Upreti

    2017-02-01

    Full Text Available Purpose: To investigate the interobserver variations in delineation of lumpectomy cavity (LC and clinical target volume (CTV, and its impact on irradiated volume in accelerated partial breast irradiation using intraoperative multicatheter brachytherapy. Material and methods : Delineation of LC and CTV was done by five radiation oncologists on planning computed tomography (CT scans of 20 patients with intraoperative interstitial breast implant. Cavity visualization index (CVI, four-point index ranging from (0 = poor to (3 = excellent was created and assigned by observers for each patient. In total, 200 contours for all observers and 100 treatment plans were evaluated. Spatial concordance (conformity index, CI common , and CIgen, average shift in the center of mass (COM, and ratio of maximum and minimum volumes (V max /V min of LC and CTV were quantified among all observers and statistically analyzed. Variation in active dwell positions (0.5 cm step for each catheter, total reference air kerma (TRAK, volume enclosed by prescription isodose (V100% among observers and its spatial concordance were analyzed. Results : The mean ± SD CI common of LC and CTV was 0.54 ± 0.09, and 0.58 ± 0.08, respectively. Conformity index tends to increase, shift in COM and V max /V min decrease significantly (p < 0.05, as CVI increased. Out of total 309 catheters, 29.8% catheters had no change, 29.8% and 17.5% catheters had variations of 1 and 2 dwell positions (0.5 cm and 1 cm, respectively. 9.3% catheters shown variations ≥ 10 dwell positions (5 cm. The mean ± SD CI common of V100% was 0.75 ± 0.11. The mean observed V max /V min of prescription isodose and TRAK was 1.18 (range, 1.03 to 1.56 and 1.11 (range, 1.03 to 1.35, respectively. Conclusions : Interobserver variability in delineation of target volume was found to be significantly related to CVI. Smaller variability was observed with excellent visualization of LC. Interobserver variations showed dosimetric

  12. Molecular theory of partial molar volume and its applications to biomolecular systems

    Directory of Open Access Journals (Sweden)

    T.Imai

    2007-09-01

    Full Text Available The paial molar volume (PMV is a thermodynamic quantity which contains important information about the solute-solvent interactions as well as the solute structure in solution.Additionally, the PMV is the most essential quantity in the analysis of the pressure effect on chemical reactions. This aicle reviews the recent developments in molecular theories of the PMV, especially the reference interaction site model (RISMtheory of molecular liquids and its three-dimensional generalization version (3D-RISM, which are combined with the Kirkwood-Buff solution theory to calculate the PMV. This aicle also introduces our recent applications of the theory to some interesting issues concerning the PMV of biomolecules. In addition, theoretical representations of the effects of intramolecular fluctuation on the PMV, which are significant for biomacromolecules, are briefly discussed.

  13. The unbiasedness of a generalized mirage boundary correction method for Monte Carlo integration estimators of volume

    Science.gov (United States)

    Thomas B. Lynch; Jeffrey H. Gove

    2014-01-01

    The typical "double counting" application of the mirage method of boundary correction cannot be applied to sampling systems such as critical height sampling (CHS) that are based on a Monte Carlo sample of a tree (or debris) attribute because the critical height (or other random attribute) sampled from a mirage point is generally not equal to the critical...

  14. Morphological image processing operators. Reduction of partial volume effects to improve 3D visualization based on CT data

    International Nuclear Information System (INIS)

    Beier, J.; Bittner, R.C.; Hosten, N.; Troeger, J.; Felix, R.

    1998-01-01

    Aim: The quality of segmentation and three-dimensional reconstruction of anatomical structures in tomographic slices is often impaired by disturbances due to partial volume effects (PVE). The potential for artefact reduction by use of the morphological image processing operators (MO) erosion and dilation is investigated. Results: For all patients under review, the artefacts caused by PVE were significantly reduced by erosion (lung: Mean SBR pre =1.67, SBR post =4.83; brain: SBR pre =1.06, SBR post =1.29) even with only a small number of iterations. Region dilation was applied to integrate further structures (e.g. at tumor borders) into a configurable neighbourhood for segmentation and quantitative analysis. Conclusions: The MO represent an efficient approach for the reduction of PVE artefacts in 3D-CT reconstructions and allow optimised visualization of individual objects. (orig./AJ) [de

  15. A novel method for the angiographic estimation of the percentage of spleen volume embolized during partial splenic embolization

    Energy Technology Data Exchange (ETDEWEB)

    Ou, Ming-Ching; Chuang, Ming-Tsung [Department of Diagnostic Radiology, National Cheng-Kung University Hospital, No. 138 Sheng Li Road, Tainan 704, Taiwan, ROC (China); Lin, Xi-Zhang [Department of Internal Medicine, National Cheng-Kung University Hospital, No. 138 Sheng Li Road, Tainan 704, Taiwan, ROC (China); Tsai, Hong-Ming; Chen, Shu-Yuan [Department of Diagnostic Radiology, National Cheng-Kung University Hospital, No. 138 Sheng Li Road, Tainan 704, Taiwan, ROC (China); Liu, Yi-Sheng, E-mail: taicheng100704@yahoo.com.tw [Department of Diagnostic Radiology, National Cheng-Kung University Hospital, No. 138 Sheng Li Road, Tainan 704, Taiwan, ROC (China)

    2013-08-15

    Purpose: To evaluate the efficacy of estimating the volume of spleen embolized in partial splenic embolization (PSE) by measuring the diameters of the splenic artery and its branches. Materials and methods: A total of 43 liver cirrhosis patients (mean age, 62.19 ± 9.65 years) with thrombocytopenia were included. Among these, 24 patients underwent a follow-up CT scan which showed a correlation between angiographic estimation and measured embolized splenic volume. Estimated splenic embolization volume was calculated by a method based on diameters of the splenic artery and its branches. The diameters of each of the splenic arteries and branches were measured via 2D angiographic images. Embolization was performed with gelatin sponges. Patients underwent follow-up with serial measurement of blood counts and liver function tests. The actual volume of embolized spleen was determined by computed tomography (CT) measuring the volumes of embolized and non-embolized spleen two months after PSE. Results: PSE was performed without immediate major complications. The mean WBC count significantly increased from 3.81 ± 1.69 × 10{sup 3}/mm{sup 3} before PSE to 8.56 ± 3.14 × 10{sup 3}/mm{sup 3} at 1 week after PSE (P < 0.001). Mean platelet count significantly increased from 62.00 ± 22.62 × 10{sup 3}/mm{sup 3} before PSE to 95.40 ± 46.29 × 10{sup 3}/mm{sup 3} 1 week after PSE (P < 0.001). The measured embolization ratio was positively correlated with estimated embolization ratio (Spearman's rho [ρ] = 0.687, P < 0.001). The mean difference between the actual embolization ratio and the estimated embolization ratio was 16.16 ± 8.96%. Conclusions: The method provides a simple method to quantitatively estimate embolized splenic volume with a correlation of measured embolization ratio to estimated embolization ratio of Spearman's ρ = 0.687.

  16. Concurrent correction of geometric distortion and motion using the map-slice-to-volume method in echo-planar imaging.

    Science.gov (United States)

    Yeo, Desmond T B; Fessler, Jeffrey A; Kim, Boklye

    2008-06-01

    The accuracy of measuring voxel intensity changes between stimulus and rest images in fMRI echo-planar imaging (EPI) data is severely degraded in the presence of head motion. In addition, EPI is sensitive to susceptibility-induced geometric distortions. Head motion causes image shifts and associated field map changes that induce different geometric distortion at different time points. Conventionally, geometric distortion is "corrected" with a static field map independently of image registration. That approach ignores all field map changes induced by head motion. This work evaluates the improved motion correction capability of mapping slice to volume with concurrent iterative field corrected reconstruction using updated field maps derived from an initial static field map that has been spatially transformed and resampled. It accounts for motion-induced field map changes for translational and in-plane rotation motion. The results from simulated EPI time series data, in which motion, image intensity and activation ground truths are available, show improved accuracy in image registration, field corrected image reconstruction and activation detection.

  17. Aqueous partial molar heat capacities and volumes for NaReO4 and NaTcO4

    International Nuclear Information System (INIS)

    Lemire, R.J.; Saluja, P.P.S.; Campbell, A.B.

    1989-01-01

    As part of the Canadian Nuclear Fuel Waste Management Program, data are required to model the equilibrium thermodynamic behavior of key radionuclides at temperatures above 25 degree C. A flow microcalorimeter/densimeter system has been commissioned to measure heat capacities and densities of solutions containing radioactive species. Measurements for solutions of aqueous NaReO 4 (a common analogue for NaTcO 4 ) were made at seven temperatures (15 to 100 degree C) over the concentration range 0.05 to 0.2 mol·kg -1 . Subsequently, measurements were made for NaTcO 4 solutions under similar conditions. The heat capacity and density data are analyzed using Pitzer's ion-interaction model, and values of the NaReO 4 partial molar heat capacities are compared to literature values based on integral heats of solution. The agreement between the two sets of NaReO 4 data is good below 75 degree C, but only fair at the higher temperatures. Values of the partial molar volumes have also been derived. The uncertainties introduced by using thermodynamic data for ReO 4 - , in the absence of data for TcO 4 - , are discussed

  18. Impact of PET - CT motion correction in minimising the gross tumour volume in non-small cell lung cancer

    Directory of Open Access Journals (Sweden)

    Michael Masoomi

    2013-10-01

    Full Text Available AbstractObjective: To investigate the impact of respiratory motion on localization, and quantification lung lesions for the Gross Tumour Volume utilizing an in-house developed Auto3Dreg programme and dynamic NURBS-based cardiac-torso digitised phantom (NCAT. Methods: Respiratory motion may result in more than 30% underestimation of the SUV values of lung, liver and kidney tumour lesions. The motion correction technique adopted in this study was an image-based motion correction approach using, an in-house developed voxel-intensity-based and a multi-resolution multi-optimisation (MRMO algorithm. All the generated frames were co-registered to a reference frame using a time efficient scheme. The NCAT phantom was used to generate CT attenuation maps and activity distribution volumes for the lung regions. Quantitative assessment including Region of Interest (ROI, image fidelity and image correlation techniques, as well as semi-quantitative line profile analysis and qualitatively overlaying non-motion and motion corrected image frames were performed. Results: the largest transformation was observed in the Z-direction. The greatest translation was for the frame 3, end inspiration, and the smallest for the frame 5 which was closet frame to the reference frame at 67% expiration. Visual assessment of the lesion sizes, 20-60mm at 3 different locations, apex, mid and base of lung showed noticeable improvement for all the foci and their locations. The maximum improvements for the image fidelity were from 0.395 to 0.930 within the lesion volume of interest. The greatest improvement in activity concentration underestimation, post motion correction, was 7% below the true activity for the 20 mm lesion. The discrepancies in activity underestimation were reduced with increasing the lesion sizes. Overlay activity distribution on the attenuation map showed improved localization of the PET metabolic information to the anatomical CT images. Conclusion: The respiratory

  19. Simultaneous determination of penicillin G salts by infrared spectroscopy: Evaluation of combining orthogonal signal correction with radial basis function-partial least squares regression

    Science.gov (United States)

    Talebpour, Zahra; Tavallaie, Roya; Ahmadi, Seyyed Hamid; Abdollahpour, Assem

    2010-09-01

    In this study, a new method for the simultaneous determination of penicillin G salts in pharmaceutical mixture via FT-IR spectroscopy combined with chemometrics was investigated. The mixture of penicillin G salts is a complex system due to similar analytical characteristics of components. Partial least squares (PLS) and radial basis function-partial least squares (RBF-PLS) were used to develop the linear and nonlinear relation between spectra and components, respectively. The orthogonal signal correction (OSC) preprocessing method was used to correct unexpected information, such as spectral overlapping and scattering effects. In order to compare the influence of OSC on PLS and RBF-PLS models, the optimal linear (PLS) and nonlinear (RBF-PLS) models based on conventional and OSC preprocessed spectra were established and compared. The obtained results demonstrated that OSC clearly enhanced the performance of both RBF-PLS and PLS calibration models. Also in the case of some nonlinear relation between spectra and component, OSC-RBF-PLS gave satisfactory results than OSC-PLS model which indicated that the OSC was helpful to remove extrinsic deviations from linearity without elimination of nonlinear information related to component. The chemometric models were tested on an external dataset and finally applied to the analysis commercialized injection product of penicillin G salts.

  20. Visual and semiquantitative analysis of 18F-fluorodeoxyglucose positron emission tomography using a partial-ring tomograph without attenuation correction to differentiate benign and malignant pulmonary nodules

    International Nuclear Information System (INIS)

    Skehan, S.J.; Coates, G.; Otero, C.; O'Donovan, N.; Pelling, M.; Nahmias, C.

    2001-01-01

    Many studies have reported the use of attenuation-corrected positron emission tomography with 18 F-fluorodeoxyglucose (FDG PET) with full-ring tomographs to differentiate between benign and malignant pulmonary nodules. We sought to evaluate FDG PET using a partial-ring tomograph without attenuation correction. A retrospective review of PET images from 77 patients (range 38-84 years of age) with proven benign or malignant pulmonary nodules was undertaken. All images were obtained using a Siemens/CTI ECAT ART tomograph, without attenuation correction, after 185 MBq 18 F-FDG was injected. Images were visually graded on a 5-point scale from 'definitely malignant' to 'definitely benign,' and lesion-to-background (LB) ratios were calculated using region of interest analysis. Visual and semiquantitative analyses were compared using receiver operating characteristic analysis. Twenty lesions were benign and 57 were malignant. The mean LB ratio for benign lesions was 1.5 (range 1.0-5.7) and for malignant lesions 5.7 (range 1.2-14.1) (p < 0.001). The area under the ROC curve for LB ratio analysis was 0.95, and for visual analysis 0.91 (p = 0.39). The optimal cut-off ratio with LB ratio analysis was 1.8, giving a sensitivity of 95% and a specificity of 85%. For lesions thought to be 'definitely malignant' on visual analysis, the sensitivity was 93% and the specificity 85%. Three proven infective lesions were rated as malignant by both techniques (LB ratio 2.6-5.7). FDG PET without attenuation correction is accurate for differentiating between benign and malignant lung nodules. Results using simple LB ratios without attenuation correction compare favourably with the published sensitivity and specificity for standard uptake ratios. Visual analysis is equally accurate. (author)

  1. Clinical application of calculated split renal volume using computed tomography-based renal volumetry after partial nephrectomy: Correlation with technetium-99m dimercaptosuccinic acid renal scan data.

    Science.gov (United States)

    Lee, Chan Ho; Park, Young Joo; Ku, Ja Yoon; Ha, Hong Koo

    2017-06-01

    To evaluate the clinical application of computed tomography-based measurement of renal cortical volume and split renal volume as a single tool to assess the anatomy and renal function in patients with renal tumors before and after partial nephrectomy, and to compare the findings with technetium-99m dimercaptosuccinic acid renal scan. The data of 51 patients with a unilateral renal tumor managed by partial nephrectomy were retrospectively analyzed. The renal cortical volume of tumor-bearing and contralateral kidneys was measured using ImageJ software. Split estimated glomerular filtration rate and split renal volume calculated using this renal cortical volume were compared with the split renal function measured with technetium-99m dimercaptosuccinic acid renal scan. A strong correlation between split renal function and split renal volume of the tumor-bearing kidney was observed before and after surgery (r = 0.89, P volumetry had a strong correlation with the split renal function measured using technetium-99m dimercaptosuccinic acid renal scan. Computed tomography-based split renal volume measurement before and after partial nephrectomy can be used as a single modality for anatomical and functional assessment of the tumor-bearing kidney. © 2017 The Japanese Urological Association.

  2. Partial molar volume of mefenamic acid in alcohol at temperatures between T=293.15 and T=313.15 K

    OpenAIRE

    Iqbal, Muhammad J.; Siddiquah, Mahrukh

    2006-01-01

    Apparent molar volume (Vphi), partial molar volume (V), solute-solute interaction parameter (Sv), partial molar expansivity (E(0)2) and isobaric thermal expansion coefficient (alpha2) of mefenamic acid in six different organic solvents namely, methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, and 2-butanol, have been calculated from the measured solution densities over a temperature range of T=293.15 and T=313.15±0.1K. The solution densities were measured by an automated vibrating tube de...

  3. Thyroid hormone partially corrects the effect of diabetes on mysoin heavy chain RNAs in the rat ventricle

    International Nuclear Information System (INIS)

    Barrieux, A.; Dillmann, W.H.

    1986-01-01

    The relative abundance of the 2 cardiac myosin heavy chains (MHH-α and MHC-β) and their corresponding RNAs is similarly affected by hypothyroidism and diabetes in the rat ventricle. Since circulating levels of thyroid hormone (T 3 ) are significantly decreased in diabetes the decreased RNA-α and increased RNA-β associated with diabetes may be related to T 3 deficiency. Chronically diabetic rats were injected with T 3 , insulin (I), or both and sacrificed between 1 and 12 hrs after injection, MHC RNA was quantified by hybridization of total RNA to a [ 32 P]-cDNA MHC-α probe. Total MHC RNA was measured by retention of S1-resistant label on DE-81 while RNA-α and RNA-β were quantified by separation of intact (α) and partially digested (β) probe by gel electrophoresis. Total MHC RNA was not changed by T 3 or I (.9-1.2 ng/μg of cellular RNA). T 3 and I elicited a very rapid increase in RNA-α (18% in untreated to 38% (I) and 47% (T 3 within 1 hr). I administered either 7 hr before or 1 hr after T 3 did not modify the RNA-α increase observed after T 3 alone. However, the response of diabetic rats to T 3 was markedly different from that of hypothyroid rats. Conclusions: 1) T 3 in diabetic rats does not mimick the effect of T 3 in hypothyroid rats; it may simply impose a hyperthyroid state on the existing diabetes and 2) since neither T 3 nor I are able to increase RNA-α to control levels within 12 hrs, neither hormone is sufficient to regulate the expression of MHC RNAs

  4. Concurrent correction of geometric distortion and motion using the map-slice-to-volume method in EPI

    Science.gov (United States)

    Yeo, Desmond T. B.; Fessler, Jeffrey A.; Kim, Boklye

    2014-01-01

    The accuracy of measuring voxel intensity changes between stimulus and rest images in fMRI echo-planar imaging (EPI) data is severely degraded in the presence of head motion. In addition, EPI is sensitive to susceptibility-induced geometric distortions. Head motion causes image shifts and associated field map changes that induce different geometric distortion at different time points. Conventionally, geometric distortion is “corrected” with a static field map independently of image registration. That approach ignores all field map changes induced by head motion. This work evaluates the improved motion correction capability of mapping slice to volume (MSV) registration with concurrent iterative field corrected reconstruction using updated field maps derived from an initial static field map that has been spatially transformed and resampled. It accounts for motion-induced field map changes for translational and in-plane rotation motion. The results from simulated EPI time series data, in which motion, image intensity and activation ground truths are available, show improved accuracy in image registration, field corrected image reconstruction and activation detection. PMID:18280077

  5. Carotid wall volume quantification from magnetic resonance images using deformable model fitting and learning-based correction of systematic errors

    International Nuclear Information System (INIS)

    Hameeteman, K; Niessen, W J; Klein, S; Van 't Klooster, R; Selwaness, M; Van der Lugt, A; Witteman, J C M

    2013-01-01

    We present a method for carotid vessel wall volume quantification from magnetic resonance imaging (MRI). The method combines lumen and outer wall segmentation based on deformable model fitting with a learning-based segmentation correction step. After selecting two initialization points, the vessel wall volume in a region around the bifurcation is automatically determined. The method was trained on eight datasets (16 carotids) from a population-based study in the elderly for which one observer manually annotated both the lumen and outer wall. An evaluation was carried out on a separate set of 19 datasets (38 carotids) from the same study for which two observers made annotations. Wall volume and normalized wall index measurements resulting from the manual annotations were compared to the automatic measurements. Our experiments show that the automatic method performs comparably to the manual measurements. All image data and annotations used in this study together with the measurements are made available through the website http://ergocar.bigr.nl. (paper)

  6. Relationship between partial and average atomic volumes of components in Au-Ni alloys%Au-Ni合金中组元的平均原子体积和偏摩尔体积的关系

    Institute of Scientific and Technical Information of China (English)

    谢佑卿

    2011-01-01

    在系统合金科学框架中建立有关无序合金的平均摩尔性质(体积和势能)的函数.通过对这些函数进行推导,可以得到平均摩尔体积函数、偏摩尔体积函数及派生出与成分相关的函数.在组元的偏摩尔性质和平均摩尔性质之间的普适方程、差分方程、在偏摩尔性质和平均摩尔性质之间不同参数的约束方程和普适的Gibbs-Duhem公式.可以证明从合金平均摩尔性质的不同函数计算的偏摩尔性质是相等的,但总体来说偏摩尔性质不等于给定组元的平均摩尔性质,即偏摩尔性质不能代表相应组元的摩尔性质.通过计算Au-Ni系中组元的偏摩尔体积和平均原子体积以及合金的平均原子体积,证明所建立的公式和函数的正确性.%In the framework of systematic science of alloys,the average molar property (volume and potential energy) functions of disordered alloys were established.From these functions,the average molar property functions,partial molar property functions,derivative functions with respect to composition,general equation of relationship between partial and average molar properties of components,difference equation and constraining equation of different values between partial and average molar properties,as well as general Gibbs-Duhem formula were derived.It was proved that the partial molar properties calculated from various combinative functions of average molar properties of alloys are equal,but in general,the partial molar properties are not equal to the average molar properties of a given component.This means that the partial molar properties cannot represent the corresponding properties of the component.All the equations and functions established in this work were proved to be correct by calculating the results of partial and average atomic volumes of components as well as average atomic volumes of alloys in the Au-Ni system.

  7. A volume integral equation solver for quantum-corrected transient analysis of scattering from plasmonic nanostructures

    KAUST Repository

    Sayed, Sadeed Bin; Uysal, Ismail Enes; Bagci, Hakan; Ulku, H. Arda

    2018-01-01

    Quantum tunneling is observed between two nanostructures that are separated by a sub-nanometer gap. Electrons “jumping” from one structure to another create an additional current path. An auxiliary tunnel is introduced between the two structures as a support for this so that a classical electromagnetic solver can account for the effects of quantum tunneling. The dispersive permittivity of the tunnel is represented by a Drude model, whose parameters are obtained from the electron tunneling probability. The transient scattering from the connected nanostructures (i.e., nanostructures plus auxiliary tunnel) is analyzed using a time domain volume integral equation solver. Numerical results demonstrating the effect of quantum tunneling on the scattered fields are provided.

  8. Small volume resuscitation with hypertonic sodium chloride solution in cattle undergoing surgical correction of abomasal volvulus

    DEFF Research Database (Denmark)

    Sickinger, M.; Doll, K.; Roloff, N. C.

    2014-01-01

    .5±2.1 vs. 10.3±3.3cm H2O, respectively). Within the first 60min, the base excess decreased from 5.5±6.9 to 4.7±6.2mmol/L in the hypertonic group whereas it increased from 5.6±5.7 to 6.8±5.4mmol/L in the isotonic group. These results suggest that for cows with abomasal volvulus, IV therapy with hypertonic...... had a significantly greater reduction in volume deficit within the first 10min of therapy than cows treated with isotonic saline (from 5.9±4.8 to 2.1±4.4L/100kg vs. 7.0±4.5 to 4.9±3.8L/100kg, respectively). The central venous pressure (CVP) of the cows given the hypertonic saline rose within the first...... 10 min of therapy from 7.3±3.5 to 10.8±3.4cm H2O, while the CVP of the cattle treated with isotonic saline did not increase significantly during this time.Sixty minutes after the start of the infusion, the CVP of the isotonic group was still significantly lower than that of the hypertonic group (9...

  9. 1999 Annual Mixed Waste Management Facility Groundwater Correction - Action Report (Volumes I, II, and III)

    International Nuclear Information System (INIS)

    Chase, J.

    2000-01-01

    This Corrective Action Report (CAR) for the Mixed Waste Management Facility (MWMF) is being prepared to comply with the Resource Conservation and Recovery Act (RCRA) Permit Number SC1 890 008 989, dated October 31, 1999. This CAR compiles and presents all groundwater sampling and monitoring activities that are conducted at the MWMF. As set forth in previous agreements with South Carolina Department of Health and Environmental Control (SCDHEC), all groundwater associated with the Burial Ground Complex (BGC) (comprised of the MWMF, Low-Level Radioactive Waste Disposal Facility, and Old Radioactive Waste Burial Ground) will be addressed under this RCRA Permit. This CAR is the first to be written for the MWMF and presents monitoring activities and results as an outcome of Interim Status and limited Permitted Status activities. All 1999 groundwater monitoring activities were conducted while the MWMF was operated during Interim Status. Changes to the groundwater monitoring program were made upon receipt of the RCRA Permit, where feasible. During 1999, 152 single-screened and six multi-screened groundwater monitoring wells at the BGC monitored groundwater quality in the uppermost aquifer as required by the South Carolina Hazardous Waste Management Regulations (SCHWMR), settlement agreements 87-52-SW and 91-51-SW, and RCRA Permit SC1 890 008 989. However, overall compliance with the recently issued RCRA Permit could not be implemented until the year 2000 due to the effective date of the RCRA Permit and scheduling of groundwater monitoring activities. Changes have been made to the groundwater monitoring network to meet Permit requirements for all 2000 sampling events

  10. Thermodynamic study of (heptane + amine) mixtures. III: Excess and partial molar volumes in mixtures with secondary, tertiary, and cyclic amines at 298.15 K

    International Nuclear Information System (INIS)

    Lepori, Luciano; Gianni, Paolo; Spanedda, Andrea; Matteoli, Enrico

    2011-01-01

    Graphical abstract: Highlights: → Excess volumes of (sec., tert., or cyclic amines + heptane) mixtures. → Excess volumes are positive for small size amines and decrease as the size increases. → Group contributions to predict the partial molar volumes of amines in heptane. → The void volume is larger for sec. and tert. than for linear amines in heptane. → The void volume is much smaller for cyclic than for linear amines in heptane. - Abstract: Excess molar volumes V E at 298.15 K were determined by means of a vibrating tube densimeter for binary mixtures of {heptane + open chain secondary (diethyl to dibutyl) and tertiary (triethyl to tripentyl) amines} as well as for cyclic imines (C 2 , C 3 , C 4 , C 6 , and C 7 ) and primary cycloalkylamines (C 5 , C 6 , C 7 , and C 12 ). The V E values were found positive for mixtures involving small size amines, with V E decreasing as the size increases. Negative V E 's were found for tributyl- and tripentylamine, heptamethylenimine, and cyclododecylamine. Mixtures of heptane with cycloheptylamine showed an s-shaped curve. Partial molar volumes V 0 of amines at infinite dilution in heptane were obtained from V E and compared with V 0 of hydrocarbons and other classes of organic compounds taken from literature. An additivity scheme, based on the intrinsic volume approach, was applied to estimate group (CH 3 , CH 2 , CH, C, NH 2 , NH, N, OH, O, CO, and COO) contributions to V 0 . These contributions, the effect of cyclization on V 0 , and the limiting slope of the apparent excess molar volumes were discussed in terms of solute-solvent and solute-solute interactions.

  11. Hydration of alcohol clusters in 1-propanol-water mixture studied by quasielastic neutron scattering and an interpretation of anomalous excess partial molar volume.

    Science.gov (United States)

    Misawa, M; Inamura, Y; Hosaka, D; Yamamuro, O

    2006-08-21

    Quasielastic neutron scattering measurements have been made for 1-propanol-water mixtures in a range of alcohol concentration from 0.0 to 0.167 in mole fraction at 25 degrees C. Fraction alpha of water molecules hydrated to fractal surface of alcohol clusters in 1-propanol-water mixture was obtained as a function of alcohol concentration. Average hydration number N(ws) of 1-propanol molecule is derived from the value of alpha as a function of alcohol concentration. By extrapolating N(ws) to infinite dilution, we obtain values of 12-13 as hydration number of isolated 1-propanol molecule. A simple interpretation of structural origin of anomalous excess partial molar volume of water is proposed and as a result a simple equation for the excess partial molar volume is deduced in terms of alpha. Calculated values of the excess partial molar volumes of water and 1-propanol and the excess molar volume of the mixture are in good agreement with experimental values.

  12. Correcting human heart 31P NMR spectra for partial saturation. Evidence that saturation factors for PCr/ATP are homogeneous in normal and disease states

    Science.gov (United States)

    Bottomley, Paul A.; Hardy, Christopher J.; Weiss, Robert G.

    Heart PCr/ATP ratios measured from spatially localized 31P NMR spectra can be corrected for partial saturation effects using saturation factors derived from unlocalized chest surface-coil spectra acquired at the heart rate and approximate Ernst angle for phosphor creatine (PCr) and again under fully relaxed conditions during each 31P exam. To validate this approach in studies of normal and disease states where the possibility of heterogeneity in metabolite T1 values between both chest muscle and heart and normal and disease states exists, the properties of saturation factors for metabolite ratios were investigated theoretically under conditions applicable in typical cardiac spectroscopy exams and empirically using data from 82 cardiac 31P exams in six study groups comprising normal controls ( n = 19) and patients with dilated ( n = 20) and hypertrophic ( n = 5) cardiomyopathy, coronary artery disease ( n = 16), heart transplants ( n = 19), and valvular heart disease ( n = 3). When TR ≪ T1,(PCr), with T1(PCr) ⩾ T1(ATP), the saturation factor for PCr/ATP lies in the range 1.5 ± 0.5, regardless of the T1 values. The precise value depends on the ratio of metabolite T1 values rather than their absolute values and is insensitive to modest changes in TR. Published data suggest that the metabolite T1 ratio is the same in heart and muscle. Our empirical data reveal that the saturation factors do not vary significantly with disease state, nor with the relative fractions of muscle and heart contributing to the chest surface-coil spectra. Also, the corrected myocardial PCr/ATP ratios in each normal or disease state bear no correlation with the corresponding saturation factors nor the fraction of muscle in the unlocalized chest spectra. However, application of the saturation correction (mean value, 1.36 ± 0.03 SE) significantly reduced scatter in myocardial PCr/ATP data by 14 ± 11% (SD) ( p ⩽ 0.05). The findings suggest that the relative T1 values of PCr and ATP are

  13. A comparison of conventional surfactant treatment and partial liquid ventilation on the lung volume of injured ventilated small lungs

    International Nuclear Information System (INIS)

    Proquitté, Hans; Hartenstein, Sebastian; Wauer, Roland R; Schmalisch, Gerd; Koelsch, Uwe; Rüdiger, Mario

    2013-01-01

    As an alternative to surfactant therapy (ST), partial liquid ventilation (PLV) with perfluorocarbons (PFC) has been considered as a treatment for acute lung injury (ALI) in newborns. The instilled PFC is much heavier than the instilled surfactant and the aim of this study was to investigate whether PLV, compared to ST, increases the end-expiratory volume of the lung (V L ). Fifteen newborn piglets (age <12 h, mean weight 678 g) underwent saline lung lavage to achieve a surfactant depletion. Thereafter animals were randomized to PLV (n = 8), receiving PFC PF5080 (3M, Germany) at 30 mL kg −1 , and ST (n = 7) receiving 120 mg Curosurf®. Blood gases, hemodynamics and static compliance were measured initially (baseline), immediately after ALI, and after 240 min mechanical ventilation with either technique. Subsequently all piglets were killed; the lungs were removed in toto and frozen in liquid N 2 . After freeze-drying the lungs were cut into lung cubes (LCs) with edge lengths of 0.7 cm, to calculate V L . All LCs were weighed and the density of the dried lung tissue was calculated. No statistically significant differences between treatment groups PLV and ST (means ± SD) were noted in body weight (676 ± 16 g versus 679 ± 17 g; P = 0.974) or lung dry weight (1.64 ± 0.29 g versus 1.79 ± 0.48 g; P = 0.48). Oxygenation index and ventilatory efficacy index did not differ significantly between both groups at any time. V L (34.28 ± 6.13 mL versus 26.22 ± 8.1 mL; P < 0.05) and the density of the dried lung tissue (48.07 ± 5.02 mg mL −1 versus 69.07 ± 5.30 mg mL −1 ; P < 0.001), however, differed significantly between the PLV and ST groups. A 4 h PLV treatment of injured ventilated small lungs increased V L by 30% and decreased lung density by 31% compared to ST treatment, indicating greater lung distension after PLV compared to ST. (paper)

  14. Examining the Efficacy of Calcium Hydroxylapatite Filler With Integral Lidocaine in Correcting Volume Loss of the Jawline-A Pilot Study.

    Science.gov (United States)

    Juhász, Margit L W; Marmur, Ellen S

    2018-04-19

    Patients seek 3-dimensional volume restoration of the jawline to obtain a "defined" line. Injection of filler into the jawline is not approved by the Food and Drug Administration; however, dermatologists have injected this area with positive results, minimal adverse events, and high patient satisfaction. This study explores the efficacy of premixed calcium hydroxylapatite filler with integral lidocaine [CaHA(+)] to correct volume defects of the jawline. It examines the longevity, safety, and patient satisfaction (up to 12 months) of CaHA(+) for jawline volume loss correction. This is a single-investigator, nonblinded study. Twenty subjects received CaHA(+) filler injection in the jawline, with follow-up evaluations conducted at 14 days, 6 weeks, and 3, 6, 9, and 12 months. CaHA(+) injection in the jawline results in statistically significant restoration in volume and improvement in appearance lasting up to 12 months. Overall, subjects report "moderate" improvement on the Global Aesthetic Improvement Scale. It is important for cosmetic surgeons and dermatologists to have access to data on the efficacy and safety of injectables. The data obtained in this study show that CaHA(+) is an effective and safe option to correct jawline volume loss and is associated with high patient satisfaction.

  15. Apparent and partial molar volumes of long-chain alkyldimethylbenzylammonium chlorides and bromides in aqueous solutions at T=15 deg. C and T=25 deg. C

    International Nuclear Information System (INIS)

    Gonzalez-Perez, A.; Ruso, J.M.; Nimo, J.; Rodriguez, J.R.

    2003-01-01

    Density measurements of dodecyl- (C 12 DBACl), tetradecyl- (C 14 DBACl), hexadecyldimethylbenzylammonium chloride (C 16 DBACl) and of decyl- (C 10 DBABr) and dodecyldimethylbenzylammonium bromide (C 12 DBABr) in aqueous solutions at T=15 deg. C and T=25 deg. C have been carried out. From these results, apparent and partial molar volumes were calculated. Positive deviations from the Debye-Hueckel limiting law provide evidence for limited association at concentrations below the critical micelle concentration. The change of the apparent molar volume upon micellization was calculated. The relevant parameters have been presented in function of the alkyl chain length. Apparent molar volumes of the present compounds in the micellar phase, V phi m , and the change upon micellization, ΔV phi m , have been discussed in terms of temperature and type of counterion

  16. Studies on the partial specific volume of a poly(ethylene glycol) derivative in different solvent systems

    NARCIS (Netherlands)

    Tziatzios, C.; Precup, A.A.; Weidl, C.H.; Schubert, U.S.; Schuck, P.; Durchschlag, H.; Mächtle, W.; Broek, van den J.A.; Schubert, D.

    2002-01-01

    The specific volume of charged supramolecular compounds dissolved in organic solvents varies considerably with the solvent system applied; in addition, it is influenced by the presence of salt. In this study we determined the specific volume of an uncharged molecule from the same molar mass range in

  17. Surgical correction of Peyronie's disease via tunica albuginea plication or partial plaque excision with pericardial graft: long-term follow up.

    Science.gov (United States)

    Taylor, Frederick L; Levine, Laurence A

    2008-09-01

    Limited publications exist regarding long-term outcomes of surgical correction for Peyronie's Disease (PD). To report on long-term postoperative parameters including rigidity, curvature, length, sensation, function, and patient satisfaction in men with PD treated surgically via Tunica Albuginea Plication (TAP) or Partial Plaque Excision with Tutoplast Human Pericardial Grafting (PEG). Objective and subjective data regarding patients who underwent either TAP or PEG. We report on 142 patients (61 TAP and 81 PEG) with both objective data and subjective patient reports on their postoperative experience. Patients underwent either TAP or PEG following our previously published algorithm. Data was collected via chart review and an internally generated survey, in which patients were asked about their rigidity, straightness, penile length, sensation, sexual function and satisfaction. Average follow up for TAP patients was 72 months (range 8-147) and 58 months (range 6-185) for PEG patients. At survey time, 93% of TAP and 91% of PEG patients reported curvatures of less than 30o. Rigidity was reportedly as good as or better than preoperative in 81% of TAP and 68% of PEG patients, and was adequate for coitus in 90% of TAP and 79% of PEG patients with or without the use of PDE5i. Objective flaccid stretched penile length measurements obtained pre and postoperatively show an average overall length gain of 0.6 cm (range -3.5-3.5) for TAP and 0.2 cm (range -1.5-2.0) for PEG patients. Sensation was reportedly as good as or better than preoperative in 69% of both TAP and PEG patients; 98% of TAP patients and 90% of PEG are able to achieve orgasm. 82% of TAP patients and 75% of PEG patients were either very satisfied or satisfied. Our long-term results support both TAP and PEG as durable surgical therapy for men with clinically significant PD.

  18. Arm Volumetry Versus Upper Extremity Lymphedema Index: Validity of Upper Extremity Lymphedema Index for Body-Type Corrected Arm Volume Evaluation.

    Science.gov (United States)

    Yamamoto, Nana; Yamamoto, Takumi; Hayashi, Nobuko; Hayashi, Akitatsu; Iida, Takuya; Koshima, Isao

    2016-06-01

    Volumetry, measurement of extremity volume, is a commonly used method for upper extremity lymphedema (UEL) evaluation. However, comparison between different patients with different physiques is difficult with volumetry, because body-type difference greatly affects arm volume. Seventy arms of 35 participants who had no history of arm edema or breast cancer were evaluated. Arm volume was calculated using a summed truncated cone model, and UEL index was calculated using circumferences and body mass index (BMI). Examinees' BMI was classified into 3 groups, namely, low BMI (BMI, 25 kg/m). Arm volume and UEL index were compared with corresponding BMI groups. Mean (SD) arm volume was 1090.9 (205.5) mL, and UEL index 96.9 (5.6). There were significant differences in arm volume between BMI groups [low BMI vs middle BMI vs high BMI, 945.2 (107.4) vs 1045.2 (87.5) vs 1443.1 (244.4) mL, P 0.5]. Arm volume significantly increased with increase of BMI, whereas UEL index stayed constant regardless of BMI. Upper extremity lymphedema index would allow better body-type corrected arm volume evaluation compared with arm volumetry.

  19. Partial gigantism

    Directory of Open Access Journals (Sweden)

    М.М. Karimova

    2017-05-01

    Full Text Available A girl with partial gigantism (the increased I and II fingers of the left foot is being examined. This condition is a rare and unresolved problem, as the definite reason of its development is not determined. Wait-and-see strategy is recommended, as well as correcting operations after closing of growth zones, and forming of data pool for generalization and development of schemes of drug and radial therapeutic methods.

  20. Partial molar volumes of organic solutes in water. XXIII. Cyclic ketones at T = (298 to 573) K and pressures up to 30 MPa

    International Nuclear Information System (INIS)

    Cibulka, Ivan; Simurka, Lukas; Hnedkovsky, Lubomir; Bolotov, Alexander

    2011-01-01

    Research highlights: → In this study we examine standard molar volumes of aqueous cyclic ketones. → State parameters of measurements were (298 to 573) K and pressures up to 30 MPa. → Differences in behavior of monoketones and cyclohexane-1,4-dione were observed. → Group contribution method was designed and examined. - Abstract: Density data for dilute aqueous solutions of four cyclic ketones (cyclopentanone, cyclohexanone, cycloheptanone, and cyclohexane-1,4-dione) are presented together with standard molar volumes (partial molar volumes at infinite dilution) calculated from the experimental data. The measurements were performed at temperatures from T = 298 K up to T = 573 K. Experimental pressures were close to the saturated vapor pressure of water, and (15 and 30) MPa. The data were obtained using a high-temperature high-pressure flow vibrating-tube densimeter. Experimental standard molar volumes were correlated as a function of temperature and pressure using an empirical polynomial function. Contributions of the molecular structural segments (methylene and carbonyl groups) to the standard molar volume were also evaluated and analyzed.

  1. Effect of temperature on the partial molar volume, isentropic compressibility and viscosity of DL-2-aminobutyric acid in water and in aqueous sodium chloride solutions

    International Nuclear Information System (INIS)

    Romero, Carmen M.; Rodríguez, Diana M.; Ribeiro, Ana C.F.; Esteso, Miguel A.

    2017-01-01

    Highlights: • Apparent volumes, apparent compressibilities, viscosities of DL-2-aminobutyric acid. • Effect of temperature on the values for these properties. • Hydrophobic and hydrophilic interactions and the effect of sodium chloride. - Abstract: Density, sound velocity and viscosity of DL-2-aminobutyric acid in water and in aqueous sodium chloride solutions have been measured at temperatures of (293.15, 298.15, 303.15, 308.15 and 313.15) K. The experimental results were used to determine the apparent molar volume and the apparent molar compressibility as a function of composition at these temperatures. The limiting values of both the partial molar volume and the partial molar adiabatic compressibility at infinite dilution of DL-2-aminobutyric acid in water and in aqueous sodium chloride solutions were determined at each temperature. The experimental viscosity values were adjusted by a least-squares method to a second order equation as proposed by Tsangaris-Martin to obtain the viscosity B coefficient which depends on the size, shape and charge of the solute molecule. The influence of the temperature on the behaviour of the selected properties is discussed in terms of both the solute hydration and the balance between hydrophobic and hydrophilic interactions between the acids and water, and the effect of the sodium chloride concentration.

  2. High-quality 3D correction of ring and radiant artifacts in flat panel detector-based cone beam volume CT imaging

    Science.gov (United States)

    Abu Anas, Emran Mohammad; Kim, Jae Gon; Lee, Soo Yeol; Kamrul Hasan, Md

    2011-10-01

    The use of an x-ray flat panel detector is increasingly becoming popular in 3D cone beam volume CT machines. Due to the deficient semiconductor array manufacturing process, the cone beam projection data are often corrupted by different types of abnormalities, which cause severe ring and radiant artifacts in a cone beam reconstruction image, and as a result, the diagnostic image quality is degraded. In this paper, a novel technique is presented for the correction of error in the 2D cone beam projections due to abnormalities often observed in 2D x-ray flat panel detectors. Template images are derived from the responses of the detector pixels using their statistical properties and then an effective non-causal derivative-based detection algorithm in 2D space is presented for the detection of defective and mis-calibrated detector elements separately. An image inpainting-based 3D correction scheme is proposed for the estimation of responses of defective detector elements, and the responses of the mis-calibrated detector elements are corrected using the normalization technique. For real-time implementation, a simplification of the proposed off-line method is also suggested. Finally, the proposed algorithms are tested using different real cone beam volume CT images and the experimental results demonstrate that the proposed methods can effectively remove ring and radiant artifacts from cone beam volume CT images compared to other reported techniques in the literature.

  3. High-quality 3D correction of ring and radiant artifacts in flat panel detector-based cone beam volume CT imaging

    International Nuclear Information System (INIS)

    Anas, Emran Mohammad Abu; Hasan, Md Kamrul; Kim, Jae Gon; Lee, Soo Yeol

    2011-01-01

    The use of an x-ray flat panel detector is increasingly becoming popular in 3D cone beam volume CT machines. Due to the deficient semiconductor array manufacturing process, the cone beam projection data are often corrupted by different types of abnormalities, which cause severe ring and radiant artifacts in a cone beam reconstruction image, and as a result, the diagnostic image quality is degraded. In this paper, a novel technique is presented for the correction of error in the 2D cone beam projections due to abnormalities often observed in 2D x-ray flat panel detectors. Template images are derived from the responses of the detector pixels using their statistical properties and then an effective non-causal derivative-based detection algorithm in 2D space is presented for the detection of defective and mis-calibrated detector elements separately. An image inpainting-based 3D correction scheme is proposed for the estimation of responses of defective detector elements, and the responses of the mis-calibrated detector elements are corrected using the normalization technique. For real-time implementation, a simplification of the proposed off-line method is also suggested. Finally, the proposed algorithms are tested using different real cone beam volume CT images and the experimental results demonstrate that the proposed methods can effectively remove ring and radiant artifacts from cone beam volume CT images compared to other reported techniques in the literature.

  4. Modifying Spearman's Attenuation Equation to Yield Partial Corrections for Measurement Error--With Application to Sample Size Calculations

    Science.gov (United States)

    Nicewander, W. Alan

    2018-01-01

    Spearman's correction for attenuation (measurement error) corrects a correlation coefficient for measurement errors in either-or-both of two variables, and follows from the assumptions of classical test theory. Spearman's equation removes all measurement error from a correlation coefficient which translates into "increasing the reliability of…

  5. Buoyancy Effect of Ionic Vacancy on the Change of the Partial Molar Volume in Ferricyanide-Ferrocyanide Redox Reaction under a Vertical Gravity Field

    Directory of Open Access Journals (Sweden)

    Yoshinobu Oshikiri

    2013-01-01

    Full Text Available With a gravity electrode (GE in a vertical gravity field, the buoyancy effect of ionic vacancy on the change of the partial molar volume in the redox reaction between ferricyanide (FERRI and ferrocyanide (FERRO ions was examined. The buoyancy force of ionic vacancy takes a positive or negative value, depending on whether the rate-determining step is the production or extinction of the vacancy. Though the upward convection over an upward electrode in the FERRO ion oxidation suggests the contribution of the positive buoyancy force arising from the vacancy production, the partial molar volume of the vacancy was not measured. On the other hand, for the downward convection under a downward electrode in the FERRI ion reduction, it was not completely but partly measured by the contribution of the negative buoyancy force from the vacancy extinction. Since the lifetime of the vacancy is decreased by the collision between ionic vacancies during the convection, the former result was ascribed to the shortened lifetime due to the increasing collision efficiency in the enhanced upward convection over an upward electrode, whereas the latter was thought to arise from the elongated lifetime due to the decreasing collision efficiency by the stagnation under the downward electrode.

  6. Solubilities and partial molar volumes of N,N′-dibutyl-oxalamide, N,N′-dihexyl-oxalamide, N,N′-dioctyl-oxalamide in supercritical carbon dioxide

    International Nuclear Information System (INIS)

    Luo, Jie; Yang, Hai-Jian; Jin, Jing; Chang, Fei

    2012-01-01

    Highlights: ► Three new “CO 2 -philic” compounds were designed and synthesized. ► The tested solubility data were calculated and correlated with two models. ► Satisfactory agreements were obtained between the tested and calculated data. ► AARD was lower than 13% for Chrastil model correlation. ► The partial molar volumes V ¯ 2 for each compound were estimated. - Abstract: Three new potent CO 2 -philic compounds were synthesized and their structures were characterized by FT-IR, NMR, and elemental analysis. The solubility of the three compounds in supercritical CO 2 was determined at T = (313 to 353) K from 9.1 MPa to 15.0 MPa. The experimental data were correlated with two density-based models proposed by Bartle and Chrastil, and the calculated results showed good agreement with the tested data. The calculated data by Bartle model differed from the measured values by (6.76 to 9.60)%, and the average value of absolute relative deviations (AARD) with Chrastil model were observed to be between (7.42 to 12.27)%. Furthermore, solubility data were also utilized to estimate the partial molar volume V ¯ 2 for each compound in the supercritical phase using the theory developed by Kumar and Johnston.

  7. Fabrication of a Customized Ball Abutment to Correct a Nonparallel Implant Abutment for a Mandibular Implant-Supported Removable Partial Prosthesis: A Case Report

    OpenAIRE

    Hossein Dasht; Mohammadreza Nakhaei; Nafiseh teimouri

    2017-01-01

    Introduction: While using an implant-supported removable partial prosthesis, the implant abutments should be parallel to one another along the path of insertion. If the implants and their attachments are placed vertically on a similar occlusal plane, not only is the retention improved, the prosthesis will also be maintained for a longer period. Case Report: A 65-year-old male patient referred to the School of Dentistry in Mashhad, Iran with complaints of discomfort with the removable partial ...

  8. Efficacy and safety of a hyaluronic acid filler in subjects treated for correction of midface volume deficiency: a 24 month study

    Directory of Open Access Journals (Sweden)

    Callan P

    2013-03-01

    Full Text Available Peter Callan,1 Greg J Goodman,2 Ian Carlisle,3 Steven Liew,4 Peter Muzikants,5 Terrence Scamp,6 Michael B Halstead,7 John D Rogers71Peter Callan Plastic Surgery, Geelong, VIC, 2Dermatology Institute of Victoria, South Yarra, VIC, 3Erase Skin Rejuvenation Specialists, Malvern, VIC, 4Shape Clinic and Medispa, Darlinghurst, NSW, 5Ada Cosmetic Medicine, Glebe, NSW, 6Esteem Beauty and Day Spa, Main Beach, QLD, 7Allergan Medical Affairs, Gordon, ACT, AustraliaBackground: Hyaluronic acid (HA fillers are an established intervention for correcting facial volume deficiency. Few studies have evaluated treatment outcomes for longer than 6 months. The purpose of this study was to determine the durability of an HA filler in the correction of midface volume deficiency over 24 months, as independently evaluated by physician investigators and subjects.Methods: Subjects received treatment with Juvéderm™ Voluma™ to the malar area, based on the investigators' determination of baseline severity and aesthetic goals. The treatment was administered in one or two sessions over an initial 4-week period. Supplementary treatment was permissible at week 78, based on protocol-defined criteria. A clinically meaningful response was predefined as at least a one-point improvement on the MidFace Volume Deficit Scale (MFVDS and on the Global Aesthetic Improvement Scale (GAIS.Results: Of the 103 subjects enrolled, 84% had moderate or significant volume deficiency at baseline. At the first post-treatment evaluation (week 8, 96% were documented to be MFVDS responders, with 98% and 100% graded as GAIS responders when assessed by the subjects and investigators, respectively. At week 78, 81.7% of subjects were still MFVDS responders, with 73.2% and 78.1% being GAIS responders, respectively. Seventy-two subjects completed the 24-month study, of whom 45 did not receive supplementary Voluma™ at week 78. Forty-three of the 45 (95.6% subjects were MFVDS responders, with 82.2% and 91

  9. Apparent and standard partial molar heat capacities and volumes of aqueous tartaric acid and its sodium salts at elevated temperature and pressure

    International Nuclear Information System (INIS)

    Xie Wei; Trevani, Liliana; Tremaine, Peter R.

    2004-01-01

    Apparent molar heat capacities and volumes have been determined for aqueous solutions of tartaric acid (H 2 Tar, Tar=C 4 H 4 O 6 ), two buffer solutions of (H 2 Tar/NaHTar) and (NaHTar/Na 2 Tar), and solutions of disodium tartrate (Na 2 Tar) at four temperatures in the range 283.15≤T/K≤328.15 at p=1 MPa. Apparent molar volumes for H 2 Tar(aq) and Na 2 Tar(aq) have been measured at temperatures 377.15≤T/K≤529.15 and p=10.4 MPa. The experimental results have been represented with a model to describe the molality and temperature dependence. Extrapolations to infinite dilution yielded standard partial molar heat capacities C p 0 and volumes V 0 for the species H 2 Tar(aq), HTar - (aq) and Tar 2- (aq) over the range of experimental measurements. The temperature dependence of V 0 for Na 2 Tar(aq) is consistent with other aqueous electrolytes, while that of H 2 Tar(aq) may be anomalous, in that it does not show divergence towards increasingly positive values with increasing temperature

  10. Ultrasound Measurements of Thyroid Gland Volume at 36 Weeks' Corrected Gestational Age in Extremely Preterm Infants Born before 28 Weeks' Gestation.

    Science.gov (United States)

    Ng, Sze May; Turner, Mark A; Avula, Shivaram

    2018-01-01

    Thyroid ultrasound is a non-invasive imaging tool and provides good evaluation of thyroid anatomy, location, vascularisation, and echogenicity. The aim of this study was to assess thyroid function and thyroid volume in extremely preterm infants born before 28 weeks' gestation evaluated at 36 weeks' corrected gestational age (CGA) compared to term infants' normative data in the literature. In this largest prospective UK study of extremely premature infants born at less than 28 weeks' gestation, thyroid volume measurement was assessed at 36 weeks' CGA. Fifty-five extremely preterm infants (28 males) who were born before 28 weeks' gestation were recruited to the study. All infants had ultrasound assessment of the thyroid gland at 36 weeks' CGA. We also prospectively measured thyroid stimulating hormone (TSH) and free thyroxine (FT 4 ) in all infants at the time of recruitment (within 5 days of birth), at days 14, 21, and 28, and at 36 weeks' CGA. The mean thyroid volume was measured at 0.57 mL (SD ±0.18). There was no association between mean thyroid volume and thyroid function (TSH or FT 4 ). No associations were found between mean thyroid volume and gestation or birth weight in these infants. Our findings provide a reference range with a mean thyroid volume of 0.57 mL (SD ±0.18) in this extremely preterm age group if less than 28 weeks' gestation. Thyroid volume at birth can vary from country to country due to variations in iodine intake as well as gestational age.

  11. Partial molar volumes of L-alanine, DL-serine, DL-threonine, L-histidine, glycine, and glycylglycine in water, NaCl, and DMSO aqueous solutions at T 298.15 K

    International Nuclear Information System (INIS)

    Yuan Quan; Li Zhifen; Wang Baohuai

    2006-01-01

    The apparent molar volumes of L-alanine, DL-serine, DL-threonine, L-histidine, glycine, and glycylglycine in water and in the aqueous solutions of NaCl and DMSO with various concentrations at T = 298.15 K have been measured by the precise vibrating-tube digital densimeter. The calculated partial molar volumes at infinite dilution have been used to obtain corresponding transfer volumes from water to various solutions. The experimental results show that the standard partial molar volumes of the above amino acids and peptide at the dilute DMSO aqueous solutions are very close to those in water. However, the volumes show several types of variations with the increase of the concentrations of DMSO due to different types of side chain of amino acids, which should be discussed specifically. The NaCl changes considerably the infinite dilution standard partial molar volumes of the above amino acids and peptide in the aqueous solutions. The infinite dilution standard partial molar volumes of the each amino acids and peptide increase with the concentrations of NaCl. The experimental results have been rationalized by a cosphere overlap model

  12. Differences in the dose-volume metrics with heterogeneity correction status and its influence on local control in stereotactic body radiation therapy for lung cancer

    International Nuclear Information System (INIS)

    Ueki, Nami; Matsuo, Yukinori; Nakamura, Mitsuhiro; Narabayashi, Masaru; Sakanaka, Katsuyuki; Norihisa, Yoshiki; Mizowaki, Takashi; Hiraoka, Masahiro; Shibuya, Keiko

    2013-01-01

    The purpose of this study is to evaluate the dose-volume metrics under different heterogeneity corrections and the factors associated with local recurrence (LR) after stereotactic body radiation therapy (SBRT) for non-small-cell lung cancer (NSCLC). Eighty-three patients who underwent SBRT for pathologically proven stage I NSCLC were reviewed retrospectively. The prescribed dose was 48 Gy in four fractions at the isocenter (IC) under heterogeneity correction with the Batho power law (BPL). The clinical plans were recalculated with Eclipse (Varian) for the same monitor units under the BPL and anisotropic analytical algorithm (AAA) and with no heterogeneity correction (NC). The dose at the IC, dose that covers 95% of the volume (D95), minimum dose (Min), and mean dose (Mean) of the planning target volume (PTV) were compared under each algorithm and between patients with local lesion control (LC) and LR. The IC doses under NC were significantly lower than those under the BPL and AAA. Under the BPL, the mean PTV D95, Min and Mean were 8.0, 9.4 and 7.4% higher than those under the AAA, and 9.6, 9.2 and 4.6% higher than those under NC, respectively. Under the AAA, all dose-volumetric parameters were significantly lower in T1a patients than in those with T1b and T2a. With a median follow-up of 35.9 months, LR occurred in 18 patients. Between the LC and LR groups, no significant differences were observed for any of the metrics. Even after stratification according to T-stage, no significant difference was observed between LC and LR. (author)

  13. Experimental validation of heterogeneity-corrected dose-volume prescription on respiratory-averaged CT images in stereotactic body radiotherapy for moving tumors

    International Nuclear Information System (INIS)

    Nakamura, Mitsuhiro; Miyabe, Yuki; Matsuo, Yukinori; Kamomae, Takeshi; Nakata, Manabu; Yano, Shinsuke; Sawada, Akira; Mizowaki, Takashi; Hiraoka, Masahiro

    2012-01-01

    The purpose of this study was to experimentally assess the validity of heterogeneity-corrected dose-volume prescription on respiratory-averaged computed tomography (RACT) images in stereotactic body radiotherapy (SBRT) for moving tumors. Four-dimensional computed tomography (CT) data were acquired while a dynamic anthropomorphic thorax phantom with a solitary target moved. Motion pattern was based on cos (t) with a constant respiration period of 4.0 sec along the longitudinal axis of the CT couch. The extent of motion (A 1 ) was set in the range of 0.0–12.0 mm at 3.0-mm intervals. Treatment planning with the heterogeneity-corrected dose-volume prescription was designed on RACT images. A new commercially available Monte Carlo algorithm of well-commissioned 6-MV photon beam was used for dose calculation. Dosimetric effects of intrafractional tumor motion were then investigated experimentally under the same conditions as 4D CT simulation using the dynamic anthropomorphic thorax phantom, films, and an ionization chamber. The passing rate of γ index was 98.18%, with the criteria of 3 mm/3%. The dose error between the planned and the measured isocenter dose in moving condition was within ± 0.7%. From the dose area histograms on the film, the mean ± standard deviation of the dose covering 100% of the cross section of the target was 102.32 ± 1.20% (range, 100.59–103.49%). By contrast, the irradiated areas receiving more than 95% dose for A 1 = 12 mm were 1.46 and 1.33 times larger than those for A 1 = 0 mm in the coronal and sagittal planes, respectively. This phantom study demonstrated that the cross section of the target received 100% dose under moving conditions in both the coronal and sagittal planes, suggesting that the heterogeneity-corrected dose-volume prescription on RACT images is acceptable in SBRT for moving tumors.

  14. Influence of hydrostatic pressure on dynamics and spatial distribution of protein partial molar volume: time-resolved surficial Kirkwood-Buff approach.

    Science.gov (United States)

    Yu, Isseki; Tasaki, Tomohiro; Nakada, Kyoko; Nagaoka, Masataka

    2010-09-30

    The influence of hydrostatic pressure on the partial molar volume (PMV) of the protein apomyoglobin (AMb) was investigated by all-atom molecular dynamics (MD) simulations. Using the time-resolved Kirkwood-Buff (KB) approach, the dynamic behavior of the PMV was identified. The simulated time average value of the PMV and its reduction by 3000 bar pressurization correlated with experimental data. In addition, with the aid of the surficial KB integral method, we obtained the spatial distributions of the components of PMV to elucidate the detailed mechanism of the PMV reduction. New R-dependent PMV profiles identified the regions that increase or decrease the PMV under the high pressure condition. The results indicate that besides the hydration in the vicinity of the protein surface, the outer space of the first hydration layer also significantly influences the total PMV change. These results provide a direct and detailed picture of pressure induced PMV reduction.

  15. The Partial Molar Volume and Compressibility of FeO in CaO-SiO2 Liquids: Systematic Variation with Fe2+ Coordination Change

    Science.gov (United States)

    Guo, X.; Lange, R. A.; Ai, Y.

    2009-12-01

    Iron is an important element in magmatic liquid, since its concentration can range up to 18% in some basaltic liquids, and it has two oxidation states. In order to model magmatic processes, thermodynamic descriptions of silicate melts must include precise information for both the FeO and Fe2O3 components. Currently, the partial molar volume of FeO is not as well known as that for Fe2O3 because of the difficulty of performing double-bob density measurements under reducing conditions. Yet these data are required in order to convert sound speed measurements on FeO-bearing liquids into compressibility data, which in turn are needed extend density models for magmatic liquids to elevated pressures. Moreover, there is growing evidence from the spectroscopic literature that Fe2+ occurs in 4, 5, and 6-fold coordination in silicate melts, and thus it is possible that the partial molar volume and compressibility of FeO may vary with Fe2+ coordination, and thus with melt composition. To explore these issues, we have conducted both density and relaxed sound speed measurements on liquids in the CaO-FeO-SiO2 system, where the CaO/SiO2 ratio was systematically varied at constant FeO concentration (40 mol%). Density was measured between 1594 and 1813K with the double-bob Archimedean method using molybdenum bobs and crucible in a reducing gas (1%CO-99%Ar) environment. The sounds speeds were measured under similar conditions with a frequency-sweep acoustic interferometer. The derived partial molar volume of FeO increases systematically from 13.7 to 15.2 cm3/mol at 1673 K as the CaO/SiO2 ratio increases and the Fe2+ coordination number decreases. From a comparison with the crystalline volume of FeO (halite structure; 12.06 cm3/mol), which serves as a lower limit for VFeO in silicate liquids when Fe2+ is in 6-fold coordination, we estimate that the average Fe2+ coordination in our experimental melts extends up to values between 5 and 4, consistent with the spectroscopic literature. The

  16. A new equation of correction of the specific volume of the hydrocarbons C1 to C8 liquids for the equation of state of Peng-Robinson

    International Nuclear Information System (INIS)

    Hoyos Madrigal, Bibian

    2000-01-01

    A new generalized correction equation for specific volume of hydrocarbon pure liquids is proposed. Which can be used in a wide temperature range and that do not require additional parameters for each substance. The equation was developed for the normal hydrocarbon series from methane to octane and the obtained results applied to other substances are analysed. A comparison is also made with the equation proposed by Peneloux et al. (1982) resulting. In all cases, in a better performance of the equation proposed in this work

  17. TU-G-BRA-05: Predicting Volume Change of the Tumor and Critical Structures Throughout Radiation Therapy by CT-CBCT Registration with Local Intensity Correction

    Energy Technology Data Exchange (ETDEWEB)

    Park, S; Robinson, A; Kiess, A; Quon, H; Wong, J; Lee, J [Johns Hopkins University, Baltimore, MD (United States); Plishker, W [IGI Technologies Inc., College Park, MD (United States); Shekhar, R [IGI Technologies Inc., College Park, MD (United States); Children’s National Medical Center, Washington, D.C. (United States)

    2015-06-15

    Purpose: The purpose of this study is to develop an accurate and effective technique to predict and monitor volume changes of the tumor and organs at risk (OARs) from daily cone-beam CTs (CBCTs). Methods: While CBCT is typically used to minimize the patient setup error, its poor image quality impedes accurate monitoring of daily anatomical changes in radiotherapy. Reconstruction artifacts in CBCT often cause undesirable errors in registration-based contour propagation from the planning CT, a conventional way to estimate anatomical changes. To improve the registration and segmentation accuracy, we developed a new deformable image registration (DIR) that iteratively corrects CBCT intensities using slice-based histogram matching during the registration process. Three popular DIR algorithms (hierarchical B-spline, demons, optical flow) augmented by the intensity correction were implemented on a graphics processing unit for efficient computation, and their performances were evaluated on six head and neck (HN) cancer cases. Four trained scientists manually contoured nodal gross tumor volume (GTV) on the planning CT and every other fraction CBCTs for each case, to which the propagated GTV contours by DIR were compared. The performance was also compared with commercial software, VelocityAI (Varian Medical Systems Inc.). Results: Manual contouring showed significant variations, [-76, +141]% from the mean of all four sets of contours. The volume differences (mean±std in cc) between the average manual segmentation and four automatic segmentations are 3.70±2.30(B-spline), 1.25±1.78(demons), 0.93±1.14(optical flow), and 4.39±3.86 (VelocityAI). In comparison to the average volume of the manual segmentations, the proposed approach significantly reduced the estimation error by 9%(B-spline), 38%(demons), and 51%(optical flow) over the conventional mutual information based method (VelocityAI). Conclusion: The proposed CT-CBCT registration with local CBCT intensity correction

  18. Hydrophobic hydration and anomalous excess partial molar volume of tert-butyl alcohol-water mixture studied by quasielastic neutron scattering

    International Nuclear Information System (INIS)

    Nakada, Masaru; Maruyama, Kenji; Misawa, Masakatsu; Yamamuro, Osamu

    2007-01-01

    Quasielastic neutron scattering has been used to investigate the hydration of alcohol clusters in tert-butyl alcohol-water mixture. The measurements were made in a range of alcohol concentration, x TBA , from 0.0 to 0.17 in mole fraction at 25degC. Fraction, α, of water molecules hydrated to fractal-surface of alcohol clusters in tert-butyl alcohol-water mixture was obtained as a function of alcohol concentration. Average hydration number N WS of tert-butyl alcohol molecule was derived from the value of α as a function of alcohol concentration. The value of N WS for an isolated alcohol molecule in water was 19-21. The anomalous excess partial molar volume of tert-butyl alcohol-water mixture was interpreted successfully by applying the same model with the same values of volume parameter as used for 1-propanol-water mixture, δ 1 (=-0.36 cm 3 ·mol -1 ) and δ 2 (=0.60 cm 3 ·mol -1 ). (author)

  19. The Effect of Dose-Volume Parameters and Interfraction Interval on Cosmetic Outcome and Toxicity After 3-Dimensional Conformal Accelerated Partial Breast Irradiation

    International Nuclear Information System (INIS)

    Leonard, Kara Lynne; Hepel, Jaroslaw T.; Hiatt, Jessica R.; Dipetrillo, Thomas A.; Price, Lori Lyn; Wazer, David E.

    2013-01-01

    Purpose: To evaluate dose-volume parameters and the interfraction interval (IFI) as they relate to cosmetic outcome and normal tissue effects of 3-dimensional conformal radiation therapy (3D-CRT) for accelerated partial breast irradiation (APBI). Methods and Materials: Eighty patients were treated by the use of 3D-CRT to deliver APBI at our institutions from 2003-2010 in strict accordance with the specified dose-volume constraints outlined in the National Surgical Adjuvant Breast and Bowel Project B39/Radiation Therapy Oncology Group 0413 (NSABP-B39/RTOG 0413) protocol. The prescribed dose was 38.5 Gy in 10 fractions delivered twice daily. Patients underwent follow-up with assessment for recurrence, late toxicity, and overall cosmetic outcome. Tests for association between toxicity endpoints and dosimetric parameters were performed with the chi-square test. Univariate logistic regression was used to evaluate the association of interfraction interval (IFI) with these outcomes. Results: At a median follow-up time of 32 months, grade 2-4 and grade 3-4 subcutaneous fibrosis occurred in 31% and 7.5% of patients, respectively. Subcutaneous fibrosis improved in 5 patients (6%) with extended follow-up. Fat necrosis developed in 11% of women, and cosmetic outcome was fair/poor in 19%. The relative volume of breast tissue receiving 5%, 20%, 50%, 80%, and 100% (V5-V100) of the prescribed dose was associated with risk of subcutaneous fibrosis, and the volume receiving 50%, 80%, and 100% (V50-V100) was associated with fair/poor cosmesis. The mean IFI was 6.9 hours, and the minimum IFI was 6.2 hours. The mean and minimum IFI values were not significantly associated with late toxicity. Conclusions: The incidence of moderate to severe late toxicity, particularly subcutaneous fibrosis and fat necrosis and resulting fair/poor cosmesis, remains high with continued follow-up. These toxicity endpoints are associated with several dose-volume parameters. Minimum and mean IFI values were

  20. A single-chain fusion molecule consisting of peptide, major histocompatibility gene complex class I heavy chain and beta2-microglobulin can fold partially correctly, but binds peptide inefficiently

    DEFF Research Database (Denmark)

    Sylvester-Hvid, C; Buus, S

    1999-01-01

    of a recombinant murine MHC-I molecule, which could be produced in large amounts in bacteria. The recombinant MHC-I protein was expressed as a single molecule (PepSc) consisting of the antigenic peptide linked to the MHC-I heavy chain and further linked to human beta2-microglobulin (hbeta2m). The PepSc molecule...... electrophoresis (SDS-PAGE). Serological analysis revealed the presence of some, but not all, MHC-I-specific epitopes. Biochemically, PepSc could bind peptide, however, rather ineffectively. We suggest that a partially correctly refolded MHC-I has been obtained....

  1. On Neglecting Chemical Exchange When Correcting in Vivo 31P MRS Data for Partial Saturation: Commentary on: ``Pitfalls in the Measurement of Metabolite Concentrations Using the One-Pulse Experiment in in Vivo NMR''

    Science.gov (United States)

    Ouwerkerk, Ronald; Bottomley, Paul A.

    2001-04-01

    This article replies to Spencer et al. (J. Magn. Reson.149, 251-257, 2001) concerning the degree to which chemical exchange affects partial saturation corrections using saturation factors. Considering the important case of in vivo31P NMR, we employ differential analysis to demonstrate a broad range of experimental conditions over which chemical exchange minimally affects saturation factors, and near-optimum signal-to-noise ratio is preserved. The analysis contradicts Spencer et al.'s broad claim that chemical exchange results in a strong dependence of saturation factors upon M0's and T1 and exchange parameters. For Spencer et al.'s example of a dynamic 31P NMR experiment in which phosphocreatine varies 20-fold, we show that our strategy of measuring saturation factors at the start and end of the study reduces errors in saturation corrections to 2% for the high-energy phosphates.

  2. Universality in all-{alpha}{sup Prime} order corrections to BPS/non-BPS brane world volume theories

    Energy Technology Data Exchange (ETDEWEB)

    Hatefi, Ehsan, E-mail: ehatefi@ictp.it [International Centre for Theoretical Physics, Strada Costiera 11, Trieste (Italy); Park, I.Y., E-mail: inyongpark05@gmail.com [Department of Natural and Physical Sciences, Philander Smith College, Little Rock, AR 72223 (United States)

    2012-11-21

    Knowledge of all-{alpha}{sup Prime} higher derivative corrections to leading order BPS and non-BPS brane actions would serve in future endeavor of determining the complete form of the non-abelian BPS and tachyonic effective actions. In this paper, we note that there is a universality in the all-{alpha}{sup Prime} order corrections to BPS and non-BPS branes. We compute amplitudes between one Ramond-Ramond C-field vertex operator and several SYM gauge/scalar vertex operators. Specifically, we evaluate in closed form string correlators of two-point amplitudes A{sup C{phi}}, A{sup CA}, a three-point amplitude A{sup C{phi}{phi}}, and a four-point amplitude A{sup C{phi}{phi}{phi}}. We carry out pole and contact term analysis. In particular we reproduce some of the contact terms and the infinite massless poles of A{sup C{phi}{phi}{phi}} by SYM vertices obtained through the universality.

  3. The Partial Molar Volume and Thermal Expansivity of Fe2O3 in Alkali Silicate Liquids: Evidence for the Average Coordination of Fe3+

    Science.gov (United States)

    Liu, Q.; Lange, R.

    2003-12-01

    Ferric iron is an important component in magmatic liquids, especially in those formed at subduction zones. Although it has long been known that Fe3+ occurs in four-, five- and six-fold coordination in crystalline compounds, only recently have all three Fe3+ coordination sites been confirmed in silicate glasses utilizing XANES spectroscopy at the Fe K-edge (Farges et al., 2003). Because the density of a magmatic liquid is largely determined by the geometrical packing of its network-forming cations (e.g., Si4+, Al3+, Ti4+, and Fe3+), the capacity of Fe3+ to undergo composition-induced coordination change affects the partial molar volume of the Fe2O3 component, which must be known to calculate how the ferric-ferrous ratio in magmatic liquids changes with pressure. Previous work has shown that the partial molar volume of Fe2O3 (VFe2O3) varies between calcic vs. sodic silicate melts (Mo et al., 1982; Dingwell and Brearley, 1988; Dingwell et al., 1988). The purpose of this study is to extend the data set in order to search for systematic variations in VFe2O3 with melt composition. High temperature (867-1534° C) density measurements were performed on eleven liquids in the Na2O-Fe2O3-FeO-SiO2 (NFS) system and five liquids in the K2O-Fe2O3-FeO-SiO2 (KFS) system using Pt double-bob Archimedean method. The ferric-ferrous ratio in the sodic and potassic liquids at each temperature of density measurement were calculated from the experimentally calibrated models of Lange and Carmichael (1989) and Tangeman et al. (2001) respectively. Compositions range (in mol%) from 4-18 Fe2O3, 0-3 FeO, 12-39 Na2O, 25-37 K2O, and 43-78 SiO2. Our density data are consistent with those of Dingwell et al. (1988) on similar sodic liquids. Our results indicate that for all five KFS liquids and for eight of eleven NFS liquids, the partial molar volume of the Fe2O3 component is a constant (41.57 ñ 0.14 cm3/mol) and exhibits zero thermal expansivity (similar to that for the SiO2 component). This value

  4. Experimental study of the density and derived volumetric (excess, apparent, and partial molar volumes) properties of aqueous 1-propanol mixtures at temperatures from 298 K to 582 K and pressures up to 40 MPa

    International Nuclear Information System (INIS)

    Abdulagatov, I.M.; Azizov, N.D.

    2014-01-01

    Highlights: • Density of (water + 1-propanol) mixtures. • Excess molar volumes of (water + 1-propanol) mixtures. • Apparent molar volumes of (water + 1-propanol) mixtures. -- Abstract: Densities of (water + 1-propanol) mixtures have been measured over the temperature range from 298 K to 582 K and at pressures up to 40 MPa using the constant-volume piezometer immersed in a precision liquid thermostat. The measurements were made for six compositions of (0.869, 2.465, 2.531, 7.407, 14.377, and 56.348) mol · kg −1 of 1-propanol. The expanded uncertainty of the density, pressure, temperature, and concentration measurements at the 95% confidence level with a coverage factor of k = 2 is estimated to be 0.06%, 0.05%, 15 mK, and 0.015%, respectively. The derived volumetric properties such as excess (V m E ), apparent (V Φ ), and partial (V ¯ 2 ∞ ) molar volumes were calculated using the measured values of density for the mixture and for pure components (water and 1-propanol). The concentration dependences of the apparent molar volumes were extrapolated to zero concentration to yield the partial molar volumes of 1-propanol at infinite dilution (V ¯ 2 ∞ ). The temperature, pressure, and concentration dependence of density and derived properties of the mixture were studied. All experimental and derived properties (excess, apparent, and partial molar volumes) were compared with the reported data by other authors. The small and negative values of excess molar volume for the mixtures were found at all experimental temperatures, pressures, and over the entire concentration range. The excess molar volume minimum is found at concentration about 0.4 mole fraction of 1-propanol. The concentration minimum of the derived apparent molar volumes V Φ near the 2.5 mol · kg −1 (dilute mixture) was observed

  5. How does knowledge of three-dimensional excision margins following breast conservation surgery impact upon clinical target volume definition for partial-breast radiotherapy?

    International Nuclear Information System (INIS)

    Kirby, Anna M.; Evans, Philip M.; Nerurkar, Ashutosh Y.; Desai, Saral S.; Krupa, Jaroslaw; Devalia, Haresh; Rovere, Guidubaldo Querci della; Harris, Emma J.; Kyriakidou, Julia; Yarnold, John R.

    2010-01-01

    Background and purpose: To compare partial-breast clinical target volumes generated using a standard 15 mm margin (CTV standard ) with those generated using three-dimensional surgical excision margins (CTV tailored30 ) in women who have undergone wide local excision (WLE) for breast cancer. Material and methods: Thirty-five women underwent WLE with placement of clips in the anterior, deep and coronal excision cavity walls. Distances from tumour to each of six margins were measured microscopically. Tumour bed was defined on kV-CT images using clips. CTV standard was generated by adding a uniform three-dimensional 15 mm margin, and CTV tailored30 was generated by adding 30 mm minus the excision margin in three-dimensions. Concordance between CTV standard and CTV tailored30 was quantified using conformity (CoI), geographical-miss (GMI) and normal-tissue (NTI) indices. An external-beam partial-breast irradiation (PBI) plan was generated to cover 95% of CTV standard with the 95% isodose. Percentage-volume coverage of CTV tailored30 by the 95% isodose was measured. Results: Median (range) coronal, superficial and deep excision margins were 15.0 (0.5-76.0) mm, 4.0 (0.0-60.0) mm and 4.0 (0.5-35.0) mm, respectively. Median CoI, GMI and NTI were 0.62, 0.16 and 0.20, respectively. Median coverage of CTV tailored30 by the PBI-plan was 97.7% (range 84.9-100.0%). CTV tailored30 was inadequately covered by the 95% isodose in 4/29 cases. In three cases, the excision margin in the direction of inadequate coverage was ≤2 mm. Conclusions: CTVs based on 3D excision margin data are discordant with those defined using a standard uniform 15 mm TB-CTV margin. In women with narrow excision margins, the standard TB-CTV margin could result in a geographical miss. Therefore, wider TB-CTV margins should be considered where re-excision does not occur.

  6. Impact of preoperative calculation of nephron volume loss on future of partial nephrectomy techniques; planning a strategic roadmap for improving functional preservation and securing oncological safety.

    Science.gov (United States)

    Rha, Koon H; Abdel Raheem, Ali; Park, Sung Y; Kim, Kwang H; Kim, Hyung J; Koo, Kyo C; Choi, Young D; Jung, Byung H; Lee, Sang K; Lee, Won K; Krishnan, Jayram; Shin, Tae Y; Cho, Jin-Seon

    2017-11-01

    To assess the correlation of the resected and ischaemic volume (RAIV), which is a preoperatively calculated volume of nephron loss, with the amount of postoperative renal function (PRF) decline after minimally invasive partial nephrectomy (PN) in a multi-institutional dataset. We identified 348 patients from March 2005 to December 2013 at six institutions. Data on all cases of laparoscopic (n = 85) and robot-assisted PN (n = 263) performed were retrospectively gathered. Univariable and multivariable linear regression analyses were used to identify the associations between various time points of PRF and the RAIV, as a continuous variable. The mean (sd) RAIV was 24.2 (29.2) cm 3 . The mean preoperative estimated glomerular filtration rate (eGFR) and the eGFRs at postoperative day 1, 6 and 36 months after PN were 91.0 and 76.8, 80.2 and 87.7 mL/min/1.73 m 2 , respectively. In multivariable linear regression analysis, the amount of decline in PRF at follow-up was significantly correlated with the RAIV (β 0.261, 0.165, 0.260 at postoperative day 1, 6 and 36 months after PN, respectively). This study has the limitation of its retrospective nature. Preoperatively calculated RAIV significantly correlates with the amount of decline in PRF during long-term follow-up. The RAIV could lead our research to the level of prediction of the amount of PRF decline after PN and thus would be appropriate for assessing the technical advantages of emerging techniques. © 2017 The Authors BJU International © 2017 BJU International Published by John Wiley & Sons Ltd.

  7. 18F-fluorocholine PET-guided target volume delineation techniques for partial prostate re-irradiation in local recurrent prostate cancer

    International Nuclear Information System (INIS)

    Wang Hui; Vees, Hansjoerg; Miralbell, Raymond; Wissmeyer, Michael; Steiner, Charles; Ratib, Osman; Senthamizhchelvan, Srinivasan; Zaidi, Habib

    2009-01-01

    Background and purpose: We evaluate the contribution of 18 F-choline PET/CT in the delineation of gross tumour volume (GTV) in local recurrent prostate cancer after initial irradiation using various PET image segmentation techniques. Materials and methods: Seventeen patients with local-only recurrent prostate cancer (median = 5.7 years) after initial irradiation were included in the study. Rebiopsies were performed in 10 patients that confirmed the local recurrence. Following injection of 300 MBq of 18 F-fluorocholine, dynamic PET frames (3 min each) were reconstructed from the list-mode acquisition. Five PET image segmentation techniques were used to delineate the 18 F-choline-based GTVs. These included manual delineation of contours (GTV man ) by two teams consisting of a radiation oncologist and a nuclear medicine physician each, a fixed threshold of 40% and 50% of the maximum signal intensity (GTV 40% and GTV 50% ), signal-to-background ratio-based adaptive thresholding (GTV SBR ), and a region growing (GTV RG ) algorithm. Geographic mismatches between the GTVs were also assessed using overlap analysis. Results: Inter-observer variability for manual delineation of GTVs was high but not statistically significant (p = 0.459). In addition, the volumes and shapes of GTVs delineated using semi-automated techniques were significantly higher than those of GTVs defined manually. Conclusions: Semi-automated segmentation techniques for 18 F-choline PET-guided GTV delineation resulted in substantially higher GTVs compared to manual delineation and might replace the latter for determination of recurrent prostate cancer for partial prostate re-irradiation. The selection of the most appropriate segmentation algorithm still needs to be determined.

  8. 18F-fluorocholine PET-guided target volume delineation techniques for partial prostate re-irradiation in local recurrent prostate cancer.

    Science.gov (United States)

    Wang, Hui; Vees, Hansjörg; Miralbell, Raymond; Wissmeyer, Michael; Steiner, Charles; Ratib, Osman; Senthamizhchelvan, Srinivasan; Zaidi, Habib

    2009-11-01

    We evaluate the contribution of (18)F-choline PET/CT in the delineation of gross tumour volume (GTV) in local recurrent prostate cancer after initial irradiation using various PET image segmentation techniques. Seventeen patients with local-only recurrent prostate cancer (median=5.7 years) after initial irradiation were included in the study. Rebiopsies were performed in 10 patients that confirmed the local recurrence. Following injection of 300 MBq of (18)F-fluorocholine, dynamic PET frames (3 min each) were reconstructed from the list-mode acquisition. Five PET image segmentation techniques were used to delineate the (18)F-choline-based GTVs. These included manual delineation of contours (GTV(man)) by two teams consisting of a radiation oncologist and a nuclear medicine physician each, a fixed threshold of 40% and 50% of the maximum signal intensity (GTV(40%) and GTV(50%)), signal-to-background ratio-based adaptive thresholding (GTV(SBR)), and a region growing (GTV(RG)) algorithm. Geographic mismatches between the GTVs were also assessed using overlap analysis. Inter-observer variability for manual delineation of GTVs was high but not statistically significant (p=0.459). In addition, the volumes and shapes of GTVs delineated using semi-automated techniques were significantly higher than those of GTVs defined manually. Semi-automated segmentation techniques for (18)F-choline PET-guided GTV delineation resulted in substantially higher GTVs compared to manual delineation and might replace the latter for determination of recurrent prostate cancer for partial prostate re-irradiation. The selection of the most appropriate segmentation algorithm still needs to be determined.

  9. A Prospective Pathologic Study to Define the Clinical Target Volume for Partial Breast Radiation Therapy in Women With Early Breast Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Brandon T., E-mail: Brandon.Nguyen@act.gov.au [Department of Radiation Oncology, Peter MacCallum Cancer Centre, East Melbourne, Victoria (Australia); Canberra Hospital, Radiation Oncology Department, Garran, ACT (Australia); Deb, Siddhartha [Department of Anatomical Pathology, Peter MacCallum Cancer Centre, East Melbourne, Victoria (Australia); Victorian Cancer Biobank, Cancer Council of Victoria, Carlton, Victoria (Australia); Fox, Stephen [Department of Anatomical Pathology, Peter MacCallum Cancer Centre, East Melbourne, Victoria (Australia); Hill, Prudence [Department of Anatomical Pathology, St. Vincent' s Hospital Melbourne, Fitzroy, Victoria (Australia); Collins, Marnie [Centre for Biostatistics and Clinical Trials, Peter MacCallum Cancer Centre, East Melbourne, Victoria (Australia); Chua, Boon H. [Department of Radiation Oncology, Peter MacCallum Cancer Centre, East Melbourne, Victoria (Australia); University of Melbourne, Parkville, Victoria (Australia)

    2012-12-01

    Purpose: To determine an appropriate clinical target volume for partial breast radiation therapy (PBRT) based on the spatial distribution of residual invasive and in situ carcinoma after wide local excision (WLE) for early breast cancer or ductal carcinoma in situ (DCIS). Methods and Materials: We performed a prospective pathologic study of women potentially eligible for PBRT who had re-excision and/or completion mastectomy after WLE for early breast cancer or DCIS. A pathologic assessment protocol was used to determine the maximum radial extension (MRE) of residual carcinoma from the margin of the initial surgical cavity. Women were stratified by the closest initial radial margin width: negative (>1 mm), close (>0 mm and {<=}1 mm), or involved. Results: The study population was composed of 133 women with a median age of 59 years (range, 27-82 years) and the following stage groups: 0 (13.5%), I (40.6%), II (38.3%), and III (7.5%). The histologic subtypes of the primary tumor were invasive ductal carcinoma (74.4%), invasive lobular carcinoma (12.0%), and DCIS alone (13.5%). Residual carcinoma was present in the re-excision and completion mastectomy specimens in 55.4%, 14.3%, and 7.2% of women with an involved, close, and negative margin, respectively. In the 77 women with a noninvolved radial margin, the MRE of residual disease, if present, was {<=}10 mm in 97.4% (95% confidence interval 91.6-99.5) of cases. Larger MRE measurements were significantly associated with an involved margin (P<.001), tumor size >30 mm (P=.03), premenopausal status (P=.03), and negative progesterone receptor status (P=.05). Conclusions: A clinical target volume margin of 10 mm would encompass microscopic residual disease in >90% of women potentially eligible for PBRT after WLE with noninvolved resection margins.

  10. A Prospective Pathologic Study to Define the Clinical Target Volume for Partial Breast Radiation Therapy in Women With Early Breast Cancer

    International Nuclear Information System (INIS)

    Nguyen, Brandon T.; Deb, Siddhartha; Fox, Stephen; Hill, Prudence; Collins, Marnie; Chua, Boon H.

    2012-01-01

    Purpose: To determine an appropriate clinical target volume for partial breast radiation therapy (PBRT) based on the spatial distribution of residual invasive and in situ carcinoma after wide local excision (WLE) for early breast cancer or ductal carcinoma in situ (DCIS). Methods and Materials: We performed a prospective pathologic study of women potentially eligible for PBRT who had re-excision and/or completion mastectomy after WLE for early breast cancer or DCIS. A pathologic assessment protocol was used to determine the maximum radial extension (MRE) of residual carcinoma from the margin of the initial surgical cavity. Women were stratified by the closest initial radial margin width: negative (>1 mm), close (>0 mm and ≤1 mm), or involved. Results: The study population was composed of 133 women with a median age of 59 years (range, 27-82 years) and the following stage groups: 0 (13.5%), I (40.6%), II (38.3%), and III (7.5%). The histologic subtypes of the primary tumor were invasive ductal carcinoma (74.4%), invasive lobular carcinoma (12.0%), and DCIS alone (13.5%). Residual carcinoma was present in the re-excision and completion mastectomy specimens in 55.4%, 14.3%, and 7.2% of women with an involved, close, and negative margin, respectively. In the 77 women with a noninvolved radial margin, the MRE of residual disease, if present, was ≤10 mm in 97.4% (95% confidence interval 91.6-99.5) of cases. Larger MRE measurements were significantly associated with an involved margin (P 30 mm (P=.03), premenopausal status (P=.03), and negative progesterone receptor status (P=.05). Conclusions: A clinical target volume margin of 10 mm would encompass microscopic residual disease in >90% of women potentially eligible for PBRT after WLE with noninvolved resection margins.

  11. Investigation of partial volume effect in different PET/CT systems: a comparison of results using the madeira phantom and the NEMA NU-2 2001 phantom

    International Nuclear Information System (INIS)

    Chipiga, L.; Sydoff, M.; Zvonova, I.; Bernhardsson, C.

    2016-01-01

    Positron emission tomography combined with computed tomography (PET/CT) is a quantitative technique used for diagnosing various diseases and for monitoring treatment response for different types of tumours. However, the accuracy of the data is limited by the spatial resolution of the system. In addition, the so-called partial volume effect (PVE) causes a blurring of image structures, which in turn may cause an underestimation of activity of a structure with high-activity content. In this study, a new phantom, MADEIRA (Minimising Activity and Dose with Enhanced Image quality by Radiopharmaceutical Administrations) for activity quantification in PET and single photon emission computed tomography (SPECT) was used to investigate the influence on the PVE by lesion size and tumour-to-background activity concentration ratio (TBR) in four different PET/CT systems. These measurements were compared with data from measurements with the NEMA NU-2 2001 phantom. The results with the MADEIRA phantom showed that the activity concentration (AC) values were closest to the true values at low ratios of TBR (<10) and reduced to 50 % of the actual AC values at high TBR (30-35). For all scanners, recovery of true values became closer to 1 with an increasing diameter of the lesion. The MADEIRA phantom showed good agreement with the results obtained from measurements with the NEMA NU-2 2001 phantom but allows for a wider range of possibilities in measuring image quality parameters. (authors)

  12. Attenuation corrections through energy spectra analysis of whole body and partial body measurements applying gamma spectroscopy; Schwaechungskorrektur bei gammaspektroskopischen Ganz- und Teilkoerpermessungen durch Analyse der Energiespektren

    Energy Technology Data Exchange (ETDEWEB)

    Schelper, L.F.; Lassmann, M.; Haenscheid, H.; Reiners, C. [Wuerzburg Univ. (Germany). Klinik und Poliklinik fuer Nuklearmedizin

    1997-12-01

    The study was carried out within the framework of activities for testing means of direct determination of radioactivity levels in the human body due to incorporated, inhomogenously distributed radionuclides. A major task was to derive the average depth of activity distributions, particularly from photon radiation at energies below 500 keV, for the purpose of making suitable attenuation corrections. The paper presents two applicable methods which yield information on the mean depths of activity distributions, obtained through additional analyses of the energy spectra. The analyses are based on measuring the dependence of intensity of the Compton radiation on the length of pathways of the photons penetrating the soft tissue, or on measuring the energy-dependent absorption effects with photons. (orig./CB) [Deutsch] Im Rahmen der direkten Aktivitaetsbestimmung bei inhomogener Radionukliddeposition im menschlichen Koerper mittels Ganz- oder Teilkoerpermessanlagen im klinischen Bereich oder im Strahlenschutz sollte besonders bei Photonenstrahlung mit Energien von weniger als 500 keV eine Ermittlung der mittleren Tiefe der Aktivitaetsverteilung zur Schwaechungskorrektur erfolgen. Im klinischen Umfeld ist es haeufig moeglich, zur Tiefenkorrektur die mittlere Organtiefe und damit die schwaechende Gewebsschicht mittels Ultraschall zu bestimmen. Ergaenzend hierzu werden im Folgenden zwei Methoden vorgestellt, welche Aussagen ueber die mittlere Tiefe von Aktivitaetsverteilungen durch Gewinnung von Zusatzinformationen aus dem Energiespektrum im Rahmen von gamma-spektroskopischen Personenmessungen ermoeglichen. Dazu werden einerseits die Abhaengigkeit der Intensitaet der Comptonstrahlung von der Laenge der Wegstrecke von Photonen durch Weichgewebe und andererseits energieabhaengige Absorptionseffekte bei Photonen als Grundlage herangezogen. (orig.)

  13. Estimation of an image derived input function with MR-defined carotid arteries in FDG-PET human studies using a novel partial volume correction method

    DEFF Research Database (Denmark)

    Sari, Hasan; Erlandsson, Kjell; Law, Ian

    2017-01-01

    Kinetic analysis of18F-fluorodeoxyglucose positron emission tomography data requires an accurate knowledge the arterial input function. The gold standard method to measure the arterial input function requires collection of arterial blood samples and is an invasive method. Measuring an image deriv...... input function (p > 0.12 for grey matter and white matter). Hence, the presented image derived input function extraction method can be a practical alternative to noninvasively analyze dynamic18F-fluorodeoxyglucose data without the need for blood sampling....

  14. Measurement of absolute myocardial blood flow with H215O and dynamic positron-emission tomography. Strategy for quantification in relation to the partial-volume effect

    International Nuclear Information System (INIS)

    Iida, H.; Kanno, I.; Takahashi, A.

    1988-01-01

    An in vivo technique was developed for measuring the absolute myocardial blood flow with H 2 15 O and dynamic positron-emission tomography. This technique was based on a new model involving the concept of the tissue fraction, which was defined as the fraction of the tissue mass in the volume of the region of interest. The myocardium was imaged dynamically by positron-emission tomography, starting at the time of intravenous bolus injection of H 2 15 O. The arterial input function was measured continuously with a beta-ray detector. A separate image after C 15 O inhalation was also obtained for correction of the H 2 15 O radioactivity in the blood. The absolute myocardial blood flow and the tissue fraction were calculated for 15 subjects with a kinetic technique under region-of-interest analysis. These results seem consistent with their coronary angiographic findings. The mean value of the measured absolute myocardial blood flows in normal subjects was 0.95 +/- 0.09 ml/min/g. This technique detected a diffuse decrease of myocardial blood flow in patients with triple-vessel disease

  15. Partial correction of the dwarf phenotype by non-viral transfer of the growth hormone gene in mice: Treatment age is critical.

    Science.gov (United States)

    Higuti, Eliza; Cecchi, Cláudia R; Oliveira, Nélio A J; Lima, Eliana R; Vieira, Daniel P; Aagaard, Lars; Jensen, Thomas G; Jorge, Alexander A L; Bartolini, Paolo; Peroni, Cibele N

    2016-02-01

    Non-viral transfer of the growth hormone gene to different muscles of immunodeficient dwarf (lit/scid) mice is under study with the objective of improving phenotypic correction via this particular gene therapy approach. Plasmid DNA was administered into the exposed quadriceps or non-exposed tibialis cranialis muscle of lit/scid mice followed by electroporation, monitoring several growth parameters. In a 6-month bioassay, 50μg DNA were injected three times into the quadriceps muscle of 80-day old mice. A 50% weight increase, with a catch-up growth of 21%, together with a 16% increase for nose-to-tail and tail lengths (catch-up=19-21%) and a 24-28% increase for femur length (catch-up=53-60%), were obtained. mIGF1 serum levels were ~7-fold higher than the basal levels for untreated mice, but still ~2-fold lower than in non-dwarf scid mice. Since treatment age was found to be particularly important in a second bioassay utilizing 40-day old mice, these pubertal mice were compared in a third bioassay with adult (80-day old) mice, all treated twice with 50μg DNA injected into each tibialis cranialis muscle, via a less invasive approach. mIGF1 concentrations at the same level as co-aged scid mice were obtained 15days after administration in pubertal mice. Catch-up growth, based on femur length (77%), nose-to-tail (36%) and tail length (39%) increases was 40 to 95% higher than those obtained upon treating adult mice. These data pave the way for the development of more effective pre-clinical assays in pubertal dwarf mice for the treatment of GH deficiency via plasmid-DNA muscular administration. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. Partial molar volumes and viscosities of aqueous hippuric acid solutions containing LiCl and MnCl2 · 4H2O at 303.15 K

    Science.gov (United States)

    Deosarkar, S. D.; Tawde, P. D.; Zinjade, A. B.; Shaikh, A. I.

    2015-09-01

    Density (ρ) and viscosity (η) of aqueous hippuric acid (HA) solutions containing LiCl and MnCl2 · 4H2O have been studied at 303.15 K in order to understand volumetric and viscometric behavior of these systems. Apparent molar volume (φv) of salts were calculated from density data and fitted to Massons relation and partial molar volumes (φ{v/0}) at infinite dilution were determined. Relative viscosity data has been used to determine viscosity A and B coefficients using Jones-Dole relation. Partial molar volume and viscosity coefficients have been discussed in terms of ion-solvent interactions and overall structural fittings in solution.

  17. Protein replacement therapy partially corrects the cholesterol-storage phenotype in a mouse model of Niemann-Pick type C2 disease.

    Directory of Open Access Journals (Sweden)

    Gitte Krogh Nielsen

    Full Text Available Niemann-Pick type C2 (NPC2 disease is a fatal autosomal recessive neurovisceral degenerative disorder characterized by late endosomal-lysosomal sequestration of low-density lipoprotein derived cholesterol. The breach in intracellular cholesterol homeostasis is caused by deficiency of functional NPC2, a soluble sterol binding protein targeted to the lysosomes by binding the mannose-6-phosphate receptor. As currently there is no effective treatment for the disorder, we have investigated the efficacy of NPC2 replacement therapy in a murine gene-trap model of NPC2-disease generated on the 129P2/OlaHsd genetic background. NPC2 was purified from bovine milk and its functional competence assured in NPC2-deficient fibroblasts using the specific cholesterol fluorescent probe filipin. For evaluation of phenotype correction in vivo, three-week-old NPC2(-/- mice received two weekly intravenous injections of 5 mg/kg NPC2 until trial termination 66 days later. Whereas the saline treated NPC2(-/- mice exhibited massive visceral cholesterol storage as compared to their wild-type littermates, administration of NPC2 caused a marked reduction in cholesterol build up. The histological findings, indicating an amelioration of the disease pathology in liver, spleen, and lungs, corroborated the biochemical results. Little or no difference in the overall cholesterol levels was observed in the kidneys, blood, cerebral cortex and hippocampus when comparing NPC2(-/- and wild type mice. However, cerebellum cholesterol was increased about two fold in NPC2(-/- mice compared with wild-type littermates. Weight gain performance was slightly improved as a result of the NPC2 treatment but significant motor coordination deficits were still observed. Accordingly, ultrastructural cerebellar abnormalities were detected in both saline treated and NPC2 treated NPC2(-/- animals 87 days post partum. Our data indicate that protein replacement may be a beneficial therapeutic approach in the

  18. Variation and decomposition of the partial molar volume of small gas molecules in different organic solvents derived from molecular dynamics simulations.

    Science.gov (United States)

    Klähn, Marco; Martin, Alistair; Cheong, Daniel W; Garland, Marc V

    2013-12-28

    The partial molar volumes, V(i), of the gas solutes H2, CO, and CO2, solvated in acetone, methanol, heptane, and diethylether are determined computationally in the limit of infinite dilution and standard conditions. Solutions are described with molecular dynamics simulations in combination with the OPLS-aa force field for solvents and customized force field for solutes. V(i) is determined with the direct method, while the composition of V(i) is studied with Kirkwood-Buff integrals (KBIs). Subsequently, the amount of unoccupied space and size of pre-formed cavities in pure solvents is determined. Additionally, the shape of individual solvent cages is analyzed. Calculated V(i) deviate only 3.4 cm(3) mol(-1) (7.1%) from experimental literature values. Experimental V(i) variations across solutions are reproduced qualitatively and also quantitatively in most cases. The KBI analysis identifies differences in solute induced solvent reorganization in the immediate vicinity of H2 (<0.7 nm) and solvent reorganization up to the third solvation shell of CO and CO2 (<1.6 nm) as the origin of V(i) variations. In all solutions, larger V(i) are found in solvents that exhibit weak internal interactions, low cohesive energy density and large compressibility. Weak internal interactions facilitate solvent displacement by thermal solute movement, which enhances the size of solvent cages and thus V(i). Additionally, attractive electrostatic interactions of CO2 and the solvents, which do not depend on internal solvent interactions only, partially reversed the V(i) trends observed in H2 and CO solutions where electrostatic interactions with the solvents are absent. More empty space and larger pre-formed cavities are found in solvents with weak internal interactions, however, no evidence is found that solutes in any considered solvent are accommodated in pre-formed cavities. Individual solvent cages are found to be elongated in the negative direction of solute movement. This wake behind

  19. Variation and decomposition of the partial molar volume of small gas molecules in different organic solvents derived from molecular dynamics simulations

    Science.gov (United States)

    Klähn, Marco; Martin, Alistair; Cheong, Daniel W.; Garland, Marc V.

    2013-12-01

    The partial molar volumes, bar V_i, of the gas solutes H2, CO, and CO2, solvated in acetone, methanol, heptane, and diethylether are determined computationally in the limit of infinite dilution and standard conditions. Solutions are described with molecular dynamics simulations in combination with the OPLS-aa force field for solvents and customized force field for solutes. bar V_i is determined with the direct method, while the composition of bar V_i is studied with Kirkwood-Buff integrals (KBIs). Subsequently, the amount of unoccupied space and size of pre-formed cavities in pure solvents is determined. Additionally, the shape of individual solvent cages is analyzed. Calculated bar V_i deviate only 3.4 cm3 mol-1 (7.1%) from experimental literature values. Experimental bar V_i variations across solutions are reproduced qualitatively and also quantitatively in most cases. The KBI analysis identifies differences in solute induced solvent reorganization in the immediate vicinity of H2 (<0.7 nm) and solvent reorganization up to the third solvation shell of CO and CO2 (<1.6 nm) as the origin of bar V_i variations. In all solutions, larger bar V_i are found in solvents that exhibit weak internal interactions, low cohesive energy density and large compressibility. Weak internal interactions facilitate solvent displacement by thermal solute movement, which enhances the size of solvent cages and thus bar V_i. Additionally, attractive electrostatic interactions of CO2 and the solvents, which do not depend on internal solvent interactions only, partially reversed the bar V_i trends observed in H2 and CO solutions where electrostatic interactions with the solvents are absent. More empty space and larger pre-formed cavities are found in solvents with weak internal interactions, however, no evidence is found that solutes in any considered solvent are accommodated in pre-formed cavities. Individual solvent cages are found to be elongated in the negative direction of solute

  20. SU-F-BRA-14: Optimization of Dosimetric Guidelines for Accelerated Partial Breast Irradiation (APBI) Using the Strut-Adjusted Volume Implant (SAVI)

    International Nuclear Information System (INIS)

    Mooney, K; Altman, M; Garcia-Ramirez, J; Thomas, M; Zoberi, I; Mullen, D; DeWees, T; Esthappan, J

    2015-01-01

    Purpose: Treatment planning guidelines for accelerated partial breast irradiation (ABPI) using the strut-adjusted volume implant (SAVI) are inconsistent between the manufacturer and NSABP B-39/RTOG 0413 protocol. Furthermore neither set of guidelines accounts for different applicator sizes. The purpose of this work is to establish guidelines specific to the SAVI that are based on clinically achievable dose distributions. Methods: Sixty-two consecutive patients were implanted with a SAVI and prescribed to receive 34 Gy in 10 fractions twice daily using high dose-rate (HDR) Ir-192 brachytherapy. The target (PTV-EVAL) was defined per NSABP. The treatments were planned and evaluated using a combination of dosimetric planning goals provided by the NSABP, the manufacturer, and our prior clinical experience. Parameters evaluated included maximum doses to skin and ribs, and volumes of PTV-EVAL receiving 90%, 95%, 100%, 150%, and 200% of the prescription (V90, etc). All target parameters were evaluated for correlation with device size using the Pearson correlation coefficient. Revised dosimetric guidelines for target coverage and heterogeneity were determined from this population. Results: Revised guidelines for minimum target coverage (ideal in parentheses): V90≥95%(97%), V95≥90%(95%), V100≥88%(91%). The only dosimetric parameters that were significantly correlated (p<0.05) with device size were V150 and V200. Heterogeneity criteria were revised for the 6–1 Mini/6-1 applicators to V150≤30cc and V200≤15cc, and unchanged for the other sizes. Re-evaluation of patient plans showed 90% (56/62) met the revised minimum guidelines and 76% (47/62) met the ideal guidelines. All and 56/62 patients met our institutional guidelines for maximum skin and rib dose, respectively. Conclusions: We have optimized dosimetric guidelines for the SAVI applicators, and found that implementation of these revised guidelines for SAVI treatment planning yielded target coverage exceeding

  1. Cul3-mediated Nrf2 ubiquitination and antioxidant response element (ARE) activation are dependent on the partial molar volume at position 151 of Keap1.

    Science.gov (United States)

    Eggler, Aimee L; Small, Evan; Hannink, Mark; Mesecar, Andrew D

    2009-07-29

    Nrf2 (nuclear factor erythroid 2-related factor 2) is a transcription factor that activates transcription of a battery of cytoprotective genes by binding to the ARE (antioxidant response element). Nrf2 is repressed by the cysteine-rich Keap1 (kelch-like ECH-associated protein 1) protein, which targets Nrf2 for ubiquitination and subsequent degradation by a Cul3 (cullin 3)-mediated ubiquitination complex. We find that modification of Cys(151) of human Keap1, by mutation to a tryptophan, relieves the repression by Keap1 and allows activation of the ARE by Nrf2. The Keap1 C151W substitution has a decreased affinity for Cul3, and can no longer serve to target Nrf2 for ubiquitination, though it retains its affinity for Nrf2. A series of 12 mutant Keap1 proteins, each containing a different residue at position 151, was constructed to explore the chemistry required for this effect. The series reveals that the extent to which Keap1 loses the ability to target Nrf2 for degradation, and hence the ability to repress ARE activation, correlates well with the partial molar volume of the residue. Other physico-chemical properties do not appear to contribute significantly to the effect. Based on this finding, a structural model is proposed whereby large residues at position 151 cause steric clashes that lead to alteration of the Keap1-Cul3 interaction. This model has significant implications for how electrophiles which modify Cys(151), disrupt the repressive function of Keap1.

  2. An analysis of the nucleon spectrum from lattice partially-quenched QCD

    Energy Technology Data Exchange (ETDEWEB)

    Armour, W. [Swansea University, Swansea, SA2 8PP, Wales, U.K.; Allton, C. R. [Swansea University, Swansea, SA2 8PP, Wales, U.K.; Leinweber, Derek B. [Univ. of Adelaide, SA (Australia); Thomas, Anthony W. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); College of William and Mary, Williamsburg, VA (United States); Young, Ross D. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2010-09-01

    The chiral extrapolation of the nucleon mass, Mn, is investigated using data coming from 2-flavour partially-quenched lattice simulations. The leading one-loop corrections to the nucleon mass are derived for partially-quenched QCD. A large sample of lattice results from the CP-PACS Collaboration is analysed, with explicit corrections for finite lattice spacing artifacts. The extrapolation is studied using finite range regularised chiral perturbation theory. The analysis also provides a quantitative estimate of the leading finite volume corrections. It is found that the discretisation, finite-volume and partial quenching effects can all be very well described in this framework, producing an extrapolated value of Mn in agreement with experiment. This procedure is also compared with extrapolations based on polynomial forms, where the results are less encouraging.

  3. Can adaptive threshold-based metabolic tumor volume (MTV) and lean body mass corrected standard uptake value (SUL) predict prognosis in head and neck cancer patients treated with definitive radiotherapy/chemoradiotherapy?

    Science.gov (United States)

    Akagunduz, Ozlem Ozkaya; Savas, Recep; Yalman, Deniz; Kocacelebi, Kenan; Esassolak, Mustafa

    2015-11-01

    To evaluate the predictive value of adaptive threshold-based metabolic tumor volume (MTV), maximum standardized uptake value (SUVmax) and maximum lean body mass corrected SUV (SULmax) measured on pretreatment positron emission tomography and computed tomography (PET/CT) imaging in head and neck cancer patients treated with definitive radiotherapy/chemoradiotherapy. Pretreatment PET/CT of the 62 patients with locally advanced head and neck cancer who were treated consecutively between May 2010 and February 2013 were reviewed retrospectively. The maximum FDG uptake of the primary tumor was defined according to SUVmax and SULmax. Multiple threshold levels between 60% and 10% of the SUVmax and SULmax were tested with intervals of 5% to 10% in order to define the most suitable threshold value for the metabolic activity of each patient's tumor (adaptive threshold). MTV was calculated according to this value. We evaluated the relationship of mean values of MTV, SUVmax and SULmax with treatment response, local recurrence, distant metastasis and disease-related death. Receiver-operating characteristic (ROC) curve analysis was done to obtain optimal predictive cut-off values for MTV and SULmax which were found to have a predictive value. Local recurrence-free (LRFS), disease-free (DFS) and overall survival (OS) were examined according to these cut-offs. Forty six patients had complete response, 15 had partial response, and 1 had stable disease 6 weeks after the completion of treatment. Median follow-up of the entire cohort was 18 months. Of 46 complete responders 10 had local recurrence, and of 16 partial or no responders 10 had local progression. Eighteen patients died. Adaptive threshold-based MTV had significant predictive value for treatment response (p=0.011), local recurrence/progression (p=0.050), and disease-related death (p=0.024). SULmax had a predictive value for local recurrence/progression (p=0.030). ROC curves analysis revealed a cut-off value of 14.00 mL for

  4. SU-E-J-76: Incorporation of Ultrasound Elastography in Target Volume Delineation for Partial Breast Radiotherapy Planning: A Comparative Study

    Energy Technology Data Exchange (ETDEWEB)

    Juneja, P; Harris, E; Bamber, J [The Institute of Cancer Research, London (United Kingdom); Royal Marsden NHS Foundation Trust, London (United Kingdom)

    2014-06-01

    Purpose: There is substantial observer variability in the delineation of target volumes for post-surgical partial breast radiotherapy because the tumour bed has poor x-ray contrast. This variability may result in substantial variations in planned dose distribution. Ultrasound elastography (USE) has an ability to detect mechanical discontinuities and therefore, the potential to image the scar and distortion in breast tissue architecture. The goal of this study was to compare USE techniques: strain elastography (SE), shear wave elastography (SWE) and acoustic radiation force impulse (ARFI) imaging using phantoms that simulate features of the tumour bed, for the purpose of incorporating USE in breast radiotherapy planning. Methods: Three gelatine-based phantoms (10% w/v) containing: a stiff inclusion (gelatine 16% w/v) with adhered boundaries, a stiff inclusion (gelatine 16% w/v) with mobile boundaries and fluid cavity inclusion (to mimic seroma), were constructed and used to investigate the USE techniques. The accuracy of the elastography techniques was quantified by comparing the imaged inclusion with the modelled ground-truth using the Dice similarity coefficient (DSC). For two regions of interest (ROI), the DSC measures their spatial overlap. Ground-truth ROIs were modelled using geometrical measurements from B-mode images. Results: The phantoms simulating stiff scar tissue with adhered and mobile boundaries and seroma were successfully developed and imaged using SE and SWE. The edges of the stiff inclusions were more clearly visible in SE than in SWE. Subsequently, for all these phantoms the measured DSCs were found to be higher for SE (DSCs: 0.91–0.97) than SWE (DSCs: 0.68–0.79) with an average relative difference of 23%. In the case of seroma phantom, DSC values for SE and SWE were similar. Conclusion: This study presents a first attempt to identify the most suitable elastography technique for use in breast radiotherapy planning. Further analysis will

  5. SU-E-J-76: Incorporation of Ultrasound Elastography in Target Volume Delineation for Partial Breast Radiotherapy Planning: A Comparative Study

    International Nuclear Information System (INIS)

    Juneja, P; Harris, E; Bamber, J

    2014-01-01

    Purpose: There is substantial observer variability in the delineation of target volumes for post-surgical partial breast radiotherapy because the tumour bed has poor x-ray contrast. This variability may result in substantial variations in planned dose distribution. Ultrasound elastography (USE) has an ability to detect mechanical discontinuities and therefore, the potential to image the scar and distortion in breast tissue architecture. The goal of this study was to compare USE techniques: strain elastography (SE), shear wave elastography (SWE) and acoustic radiation force impulse (ARFI) imaging using phantoms that simulate features of the tumour bed, for the purpose of incorporating USE in breast radiotherapy planning. Methods: Three gelatine-based phantoms (10% w/v) containing: a stiff inclusion (gelatine 16% w/v) with adhered boundaries, a stiff inclusion (gelatine 16% w/v) with mobile boundaries and fluid cavity inclusion (to mimic seroma), were constructed and used to investigate the USE techniques. The accuracy of the elastography techniques was quantified by comparing the imaged inclusion with the modelled ground-truth using the Dice similarity coefficient (DSC). For two regions of interest (ROI), the DSC measures their spatial overlap. Ground-truth ROIs were modelled using geometrical measurements from B-mode images. Results: The phantoms simulating stiff scar tissue with adhered and mobile boundaries and seroma were successfully developed and imaged using SE and SWE. The edges of the stiff inclusions were more clearly visible in SE than in SWE. Subsequently, for all these phantoms the measured DSCs were found to be higher for SE (DSCs: 0.91–0.97) than SWE (DSCs: 0.68–0.79) with an average relative difference of 23%. In the case of seroma phantom, DSC values for SE and SWE were similar. Conclusion: This study presents a first attempt to identify the most suitable elastography technique for use in breast radiotherapy planning. Further analysis will

  6. Partial molar volumes of organic solutes in water. XXIV. Selected alkane-α,ω-diols at temperatures T = 298 K to 573 K and pressures up to 30 MPa

    International Nuclear Information System (INIS)

    Cibulka, Ivan; Hnědkovský, Lubomír

    2013-01-01

    Highlights: • Standard molar volumes of three alkane-α,ω-diols (C 5 , C 8 , C 9 ) in water are presented. • Data were obtained in the range T from (298 to 573) K and p up to 30 MPa. • Dependences on carbon atom number, temperature, and pressure are analysed. -- Abstract: Density data for dilute aqueous solutions of three alkane-α,ω-diols (pentane-1,5-diol, octane-1,8-diol, nonane-1,9-diol) are presented together with standard molar volumes (partial molar volumes at infinite dilution) calculated from the experimental data. The measurements were performed at temperatures from T = 298 K up to T = 573 K. Experimental pressures were slightly above the saturation vapour pressure of water, and (15 and 30) MPa. The data were obtained using a high-temperature high-pressure flow vibrating-tube densimeter. Measured standard molar volumes were combined with data previously published for other members of the homologous series and discussed. Experimental standard molar volumes were correlated as a function of temperature and pressure using an empirical polynomial function. Dependences of standard molar volumes on temperature and pressure were analysed. Contributions of the methylene group to the standard molar volume were also evaluated and discussed

  7. Scintigraphic determination of the spleen volume in case of partial splenectomy for a Minkowski-Chauffard disease. About 15 cases; Determination scintigraphique du volume splenique en cas de splenectomie partielle pour une maladie de Minkowski-Chauffard. A propos de 15 cas

    Energy Technology Data Exchange (ETDEWEB)

    Berehou, F.; Ben Rais, N. [CHU Ibn Sina, Rabat, Service de medecine nucleaire (Morocco); Calzada, M.; Keller, I.; Devaux, J. [Hopital Saint-Antoine, service de medecine nucleaire, 75 - Paris (France)

    2010-07-01

    Splenic scintigraphy with labeled and fragile red blood cells is a simple, reliable, noninvasive and low radiating method to assess at long-term residual splenic volume after partial splenectomy, it is the only treatment for a good quality of life with fewer infections, fewer transfusions and without use of lifelong vaccinations for a chronic illness. (N.C.)

  8. Error Correcting Codes

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 2; Issue 3. Error Correcting Codes - Reed Solomon Codes. Priti Shankar. Series Article Volume 2 Issue 3 March ... Author Affiliations. Priti Shankar1. Department of Computer Science and Automation, Indian Institute of Science, Bangalore 560 012, India ...

  9. 10. Correctness of Programs

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 3; Issue 4. Algorithms - Correctness of Programs. R K Shyamasundar. Series Article Volume 3 ... Author Affiliations. R K Shyamasundar1. Computer Science Group, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400 005, India.

  10. Effect of PEEP and inhaled nitric oxide on pulmonary gas exchange during gaseous and partial liquid ventilation with small volumes of perfluorocarbon.

    Science.gov (United States)

    Max, M; Kuhlen, R; Falter, F; Reyle-Hahn, M; Dembinski, R; Rossaint, R

    2000-04-01

    Partial liquid ventilation, positive end-expiratory pressure (PEEP) and inhaled nitric oxide (NO) can improve ventilation/perfusion mismatch in acute lung injury (ALI). The aim of the present study was to compare gas exchange and hemodynamics in experimental ALI during gaseous and partial liquid ventilation at two different levels of PEEP, with and without the inhalation of nitric oxide. Seven pigs (24+/-2 kg BW) were surfactant-depleted by repeated lung lavage with saline. Gas exchange and hemodynamic parameters were assessed in all animals during gaseous and subsequent partial liquid ventilation at two levels of PEEP (5 and 15 cmH2O) and intermittent inhalation of 10 ppm NO. Arterial oxygenation increased significantly with a simultaneous decrease in cardiac output when PEEP 15 cmH2O was applied during gaseous and partial liquid ventilation. All other hemodynamic parameters revealed no relevant changes. Inhalation of NO and instillation of perfluorocarbon had no additive effects on pulmonary gas exchange when compared to PEEP 15 cmH2O alone. In experimental lung injury, improvements in gas exchange are most distinct during mechanical ventilation with PEEP 15 cmH2O without significantly impairing hemodynamics. Partial liquid ventilation and inhaled NO did not cause an additive increase of PaO2.

  11. Finite volume at two-loops in chiral perturbation theory

    International Nuclear Information System (INIS)

    Bijnens, Johan; Rössler, Thomas

    2015-01-01

    We calculate the finite volume corrections to meson masses and decay constants in two and three flavour Chiral Perturbation Theory to two-loop order. The analytical results are compared with the existing result for the pion mass in two-flavour ChPT and the partial results for the other quantities. We present numerical results for all quantities.

  12. Thermodynamic properties of peptide solutions 20. Partial molar volumes and isothermal compressions for some tripeptides of sequence gly-X-gly (X = gly, ala, leu, asn, thr, and tyr) in aqueous solution at T = 298.15 K and p = (10–120) MPa

    International Nuclear Information System (INIS)

    Hedwig, Gavin R.; Høiland, Harald

    2016-01-01

    Highlights: • Sound speeds were measured for aqueous solutions of some tripeptides at high pressures. • Partial molar volumes and isothermal compressions were derived for T = 298.15 K and p = (10–120) MPa. • The partial molar volumes for non-polar amino acid side-chains decrease with increasing pressure. • The partial molar volumes for polar side-chains do not change significantly with increasing pressure. - Abstract: Sound speeds have been measured for aqueous solutions of six tripeptides of sequence glycyl-X-glycine, where X is one of the amino acids glycine, alanine, leucine, asparagine, threonine, and tyrosine at T = 298.15 K and at the pressures p = (10, 20, 40, 60, 80, 100, and 120) MPa. Using methods described in previous work, these sound speeds were used to derive the partial molar volumes at infinite dilution, V_2"o, the partial molar isentropic compressions at infinite dilution, K_S_,_2"o, and the partial molar isothermal compressions at infinite dilution, K"o_T_,_2 {K"o_T_,_2 = −(∂V_2"o/∂p)_T}, for the tripeptides in aqueous solution at the elevated pressures. The results were used to calculate the partial molar volumes and partial molar isothermal compressions for the various amino acid side-chains over the pressure range p = (10–120) MPa.

  13. An analysis of the nucleon spectrum from lattice partially-quenched QCD.

    Energy Technology Data Exchange (ETDEWEB)

    Armour, W.; Allton, C. R.; Leinweber, D. B.; Thomas, A. W.; Young, R. D.; Physics; Swansea Univ.; Univ. of Adelaide; Coll. of William and Mary

    2010-09-01

    The chiral extrapolation of the nucleon mass, M{sub n}, is investigated using data coming from 2-flavour partially-quenched lattice simulations. A large sample of lattice results from the CP-PACS Collaboration is analysed using the leading one-loop corrections, with explicit corrections for finite lattice spacing artifacts. The extrapolation is studied using finite-range regularised chiral perturbation theory. The analysis also provides a quantitative estimate of the leading finite volume corrections. It is found that the discretisation, finite volume and partial quenching effects can all be very well described in this framework, producing an extrapolated value of Mn in agreement with experiment. Furthermore, determinations of the low energy constants of the nucleon mass's chiral expansion are in agreement with previous methods, but with significantly reduced errors. This procedure is also compared with extrapolations based on polynomial forms, where the results are less encouraging.

  14. An analysis of the nucleon spectrum from lattice partially-quenched QCD

    Energy Technology Data Exchange (ETDEWEB)

    Armour, W. [Department of Physics, Swansea University, Swansea SA2 8PP, Wales (United Kingdom); Allton, C.R., E-mail: c.allton@swan.ac.u [Department of Physics, Swansea University, Swansea SA2 8PP, Wales (United Kingdom); Leinweber, D.B. [Special Research Centre for the Subatomic Structure of Matter (CSSM), School of Chemistry and Physics, University of Adelaide, 5005 (Australia); Thomas, A.W. [Jefferson Lab, 12000 Jefferson Ave., Newport News, VA 23606 (United States); College of William and Mary, Williamsburg, VA 23187 (United States); Young, R.D. [Physics Division, Argonne National Laboratory, Argonne, IL 60439 (United States)

    2010-09-01

    The chiral extrapolation of the nucleon mass, M{sub n}, is investigated using data coming from 2-flavour partially-quenched lattice simulations. A large sample of lattice results from the CP-PACS Collaboration is analysed using the leading one-loop corrections, with explicit corrections for finite lattice spacing artifacts. The extrapolation is studied using finite-range regularised chiral perturbation theory. The analysis also provides a quantitative estimate of the leading finite volume corrections. It is found that the discretisation, finite volume and partial quenching effects can all be very well described in this framework, producing an extrapolated value of M{sub n} in agreement with experiment. Furthermore, determinations of the low energy constants of the nucleon mass's chiral expansion are in agreement with previous methods, but with significantly reduced errors. This procedure is also compared with extrapolations based on polynomial forms, where the results are less encouraging.

  15. What is the fundamental ion-specific series for anions and cations? Ion specificity in standard partial molar volumes of electrolytes and electrostriction in water and non-aqueous solvents.

    Science.gov (United States)

    Mazzini, Virginia; Craig, Vincent S J

    2017-10-01

    The importance of electrolyte solutions cannot be overstated. Beyond the ionic strength of electrolyte solutions the specific nature of the ions present is vital in controlling a host of properties. Therefore ion specificity is fundamentally important in physical chemistry, engineering and biology. The observation that the strengths of the effect of ions often follows well established series suggests that a single predictive and quantitative description of specific-ion effects covering a wide range of systems is possible. Such a theory would revolutionise applications of physical chemistry from polymer precipitation to drug design. Current approaches to understanding specific-ion effects involve consideration of the ions themselves, the solvent and relevant interfaces and the interactions between them. Here we investigate the specific-ion effects trends of standard partial molar volumes and electrostrictive volumes of electrolytes in water and eleven non-aqueous solvents. We choose these measures as they relate to bulk properties at infinite dilution, therefore they are the simplest electrolyte systems. This is done to test the hypothesis that the ions alone exhibit a specific-ion effect series that is independent of the solvent and unrelated to surface properties. The specific-ion effects trends of standard partial molar volumes and normalised electrostrictive volumes examined in this work show a fundamental ion-specific series that is reproduced across the solvents, which is the Hofmeister series for anions and the reverse lyotropic series for cations, supporting the hypothesis. This outcome is important in demonstrating that ion specificity is observed at infinite dilution and demonstrates that the complexity observed in the manifestation of specific-ion effects in a very wide range of systems is due to perturbations of solvent, surfaces and concentration on the underlying fundamental series. This knowledge will guide a general understanding of specific

  16. Partial molar volumes of organic solutes in water. XXVII. Two aliphatic polyethers (triglyme, tetraglyme) at temperatures T = 298–573 K and pressures up to 30 MPa

    International Nuclear Information System (INIS)

    Cibulka, Ivan

    2016-01-01

    Highlights: • Standard molar volumes of two linear aliphatic polyethers in water are presented. • Data were obtained in the range T from (298 to 573) K and p up to 30 MPa. • Data combined with those obtained previously are analyzed and compared with standard molar volumes of cyclic ethers. - Abstract: Densities of dilute aqueous solutions of two linear aliphatic polyethers: 2,5,8,11-tetraoxadodecane (triethylene glycol dimethyl ether, triglyme) and 2,5,8,11,14-pentaoxapentadecane (tetraethylene glycol dimethyl ether, tetraglyme), measured in the temperature range from (298 to 573) K and at pressures up to 30 MPa using an automated flow vibrating-tube densimeter are reported. Standard molar volumes were evaluated from the measured data. The present values complement previous measurements performed for the title polyethers at atmospheric pressure in the temperature range from (278 to 343) K and extend the knowledge to temperature and pressure ranges in which the data on standard molar volumes for lower members of the homologous series (monoglyme, diglyme) are already available.

  17. A comparative study on the volume and localization of the internal gross target volume defined using the seroma and surgical clips based on 4DCT scan for external-beam partial breast irradiation after breast conserving surgery

    International Nuclear Information System (INIS)

    Ding, Yun; Li, Jianbin; Wang, Wei; Wang, Suzhen; Wang, Jinzhi; Ma, Zhifang; Shao, Qian; Xu, Min

    2014-01-01

    To explore the volume and localization of the internal gross target volume defined using the seroma and/or surgical clips based on the four-dimensional computed tomography (4DCT) during free-breathing. Fifteen breast cancer patients after breast-conserving surgery (BCS) were recruited for EB-PBI. On the ten sets CT images, the gross target volume formed by the clips, the seroma, both the clips and seroma delineated by one radiation oncologist and defined as GTVc, GTVs and GTVc + s, respectively. The ten GTVc, GTVs and GTVc + s on the ten sets CT images produced the IGTVc, IGTVs, IGTVc + s, respectively. The IGTV volume and the distance between the center of IGTVc, IGTVs, IGTVc + s were all recorded. Conformity index (CI), degree of inclusion (DI) were calculated for IGTV/IGTV, respectively. The volume of IGTVc + s were significantly larger than the IGTVc and IGTVs (p < 0.05). There was significant difference between the DIs of IGTVc vs IGTVc + s, the DIs of IGTVs vs IGTVc + s. There was significant difference among the CIs of IGTV/IGTV. The DIs and CIs of IGTV/IGTV were negatively correlated with their centroid distance (r < 0, p < 0.05). There were volume difference and spatial mismatch between the IGTVs delineated based on the surgical clips and seroma. The IGTV defined as the seroma and surgical clips provided the best overall representation of the ‘true’ moving GTV

  18. 3Q/4Q98 Annual M-Area and Metallurgical Laboratory Hazardous Waste Management Facility Groundwater Monitoring and Correction-Action Report, Volumes I, II, and III

    International Nuclear Information System (INIS)

    Chase, J.

    1999-01-01

    This report describes the groundwater monitoring and corrective-action program at the M-Area Hazardous Waste Management Facility (HWMF) and the Metallurgical Laboratory (Met Lab) HWMF at the Savannah River Site (SRS) during 1998

  19. Solubility comparison and partial molar volumes of 1,2-hexanediol before and after end-group modification by methyl oxalyl chloride and ethyl oxalyl monochloride in supercritical CO2

    International Nuclear Information System (INIS)

    Zhao, Lu; Yang, Hai-Jian; Cai, Zhuofu

    2013-01-01

    Highlights: ► Two new “CO 2 -philic” compounds were designed and synthesized. ► The tested solubility data were calculated and correlated with two models. ► Satisfactory agreements were obtained between the tested and calculated data. ► The partial molar volumes V ¯ 2 for three compounds were estimated. - Abstract: Bis(methoxy oxalic)-1,2-haxenediester and bis(ethoxy oxalic)-1,2-haxenediester were synthesized by modifying the end groups of 1,2-hexanediol with methyl oxalyl chloride and ethyl oxalyl monochloride. The solubilities of all three compounds in supercritical carbon dioxide were determined at different conditions of pressures (8.8 to 18.8) MPa and temperatures (313, 333, and 353) K. Then, the solubility data were correlated with the Bartle model and the Chrastil model. The average absolute relative deviation (AARD) for the Bartle model was in the range of (3.89 to 25.46)% which is within a good approximation. The Chrastil model also showed satisfactory agreement and the AARD was in the range of (3.70 to 16.92)%. Furthermore, the partial molar volumes of those compounds were estimated following the theory developed by Kumar and Johnston.

  20. Partial molar volumes of organic solutes in water. XXVIII. Three aliphatic poly(ethylene glycols) at temperatures T = 298 K–573 K and pressures up to 30 MPa

    International Nuclear Information System (INIS)

    Cibulka, Ivan

    2017-01-01

    Highlights: • Standard molar volumes of three poly(ethylene glycols) in water are presented. • Data were obtained in the range T from (298 to 573) K and p up to 30 MPa. • Data are analyzed and compared with those of similar solutes. - Abstract: Densities of dilute aqueous solutions of three poly(ethylene glycols): 3-oxapentane-1,5-diol (diethylene glycol), 3,6-dioxaoctane-1,8-diol (triethylene glycol), and 3,5,9-trioxaundecane-1,11-diol (tetraethylene glycol) measured in the temperature range from (298 to 573) K and at pressures up to 30 MPa using an automated flow vibrating-tube densimeter are reported. Standard molar volumes were evaluated from the measured data. Present data complement both the previous measurements performed at atmospheric pressure in the temperature range from (278 to 343) K and the data already available for the first member of the homologous series (ethylene glycol). A comparison with data previously measured for the homologous series of linear aliphatic polyethers (poly(ethylene glycol) dimethyl ethers, glymes), diethylene glycol monomethyl ether (3,6-dioxaheptan-1-ol), and selected alkane-α,ω-diols is presented.

  1. Partial Cancellation

    Indian Academy of Sciences (India)

    First page Back Continue Last page Overview Graphics. Partial Cancellation. Full Cancellation is desirable. But complexity requirements are enormous. 4000 tones, 100 Users billions of flops !!! Main Idea: Challenge: To determine which cross-talker to cancel on what “tone” for a given victim. Constraint: Total complexity is ...

  2. M-Area and Metallurgical Laboratory Hazardous Waste Management Facilities Groundwater Monitoring and Corrective-Action Report, First and Second Quarters 1999, Volume III

    International Nuclear Information System (INIS)

    Chase, J.

    1999-01-01

    This report describes the groundwater monitoring and corrective-action program at the M-Area Hazardous Waste Management Facility (HWMF) and the Metallurgical Laboratory (Met Lab) HWMF at the Savannah River Site (SRS) during the first and second quarters 1999

  3. Partial processing

    International Nuclear Information System (INIS)

    1978-11-01

    This discussion paper considers the possibility of applying to the recycle of plutonium in thermal reactors a particular method of partial processing based on the PUREX process but named CIVEX to emphasise the differences. The CIVEX process is based primarily on the retention of short-lived fission products. The paper suggests: (1) the recycle of fission products with uranium and plutonium in thermal reactor fuel would be technically feasible; (2) it would, however, take ten years or more to develop the CIVEX process to the point where it could be launched on a commercial scale; (3) since the majority of spent fuel to be reprocessed this century will have been in storage for ten years or more, the recycling of short-lived fission products with the U-Pu would not provide an effective means of making refabrication fuel ''inaccessible'' because the radioactivity associated with the fission products would have decayed. There would therefore be no advantage in partial processing

  4. First Industrial Tests of a Drum Monitor Matrix Correction for the Fissile Mass Measurement in Large Volume Historic Metallic Residues with the Differential Die-away Technique

    Energy Technology Data Exchange (ETDEWEB)

    Antoni, R.; Passard, C.; Perot, B.; Batifol, M.; Vandamme, J.C. [CEA, DEN, Cadarache, Nuclear Measurement Laboratory, F-13108 St Paul-lez-Durance, (France); Grassi, G. [AREVA NC, 1 place Jean-Millier, 92084 Paris-La-Defense cedex (France)

    2015-07-01

    The fissile mass in radioactive waste drums filled with compacted metallic residues (spent fuel hulls and nozzles) produced at AREVA La Hague reprocessing plant is measured by neutron interrogation with the Differential Die-away measurement Technique (DDT. In the next years, old hulls and nozzles mixed with Ion-Exchange Resins will be measured. The ion-exchange resins increase neutron moderation in the matrix, compared to the waste measured in the current process. In this context, the Nuclear Measurement Laboratory (NML) of CEA Cadarache has studied a matrix effect correction method, based on a drum monitor ({sup 3}He proportional counter inside the measurement cavity). A previous study performed with the NML R and D measurement cell PROMETHEE 6 has shown the feasibility of method, and the capability of MCNP simulations to correctly reproduce experimental data and to assess the performances of the proposed correction. A next step of the study has focused on the performance assessment of the method on the industrial station using numerical simulation. A correlation between the prompt calibration coefficient of the {sup 239}Pu signal and the drum monitor signal was established using the MCNPX computer code and a fractional factorial experimental design composed of matrix parameters representative of the variation range of historical waste. Calculations have showed that the method allows the assay of the fissile mass with an uncertainty within a factor of 2, while the matrix effect without correction ranges on 2 decades. In this paper, we present and discuss the first experimental tests on the industrial ACC measurement system. A calculation vs. experiment benchmark has been achieved by performing dedicated calibration measurement with a representative drum and {sup 235}U samples. The preliminary comparison between calculation and experiment shows a satisfactory agreement for the drum monitor. The final objective of this work is to confirm the reliability of the

  5. First Industrial Tests of a Drum Monitor Matrix Correction for the Fissile Mass Measurement in Large Volume Historic Metallic Residues with the Differential Die-away Technique

    International Nuclear Information System (INIS)

    Antoni, R.; Passard, C.; Perot, B.; Batifol, M.; Vandamme, J.C.; Grassi, G.

    2015-01-01

    The fissile mass in radioactive waste drums filled with compacted metallic residues (spent fuel hulls and nozzles) produced at AREVA La Hague reprocessing plant is measured by neutron interrogation with the Differential Die-away measurement Technique (DDT. In the next years, old hulls and nozzles mixed with Ion-Exchange Resins will be measured. The ion-exchange resins increase neutron moderation in the matrix, compared to the waste measured in the current process. In this context, the Nuclear Measurement Laboratory (NML) of CEA Cadarache has studied a matrix effect correction method, based on a drum monitor ( 3 He proportional counter inside the measurement cavity). A previous study performed with the NML R and D measurement cell PROMETHEE 6 has shown the feasibility of method, and the capability of MCNP simulations to correctly reproduce experimental data and to assess the performances of the proposed correction. A next step of the study has focused on the performance assessment of the method on the industrial station using numerical simulation. A correlation between the prompt calibration coefficient of the 239 Pu signal and the drum monitor signal was established using the MCNPX computer code and a fractional factorial experimental design composed of matrix parameters representative of the variation range of historical waste. Calculations have showed that the method allows the assay of the fissile mass with an uncertainty within a factor of 2, while the matrix effect without correction ranges on 2 decades. In this paper, we present and discuss the first experimental tests on the industrial ACC measurement system. A calculation vs. experiment benchmark has been achieved by performing dedicated calibration measurement with a representative drum and 235 U samples. The preliminary comparison between calculation and experiment shows a satisfactory agreement for the drum monitor. The final objective of this work is to confirm the reliability of the modeling approach

  6. bcROCsurface: an R package for correcting verification bias in estimation of the ROC surface and its volume for continuous diagnostic tests.

    Science.gov (United States)

    To Duc, Khanh

    2017-11-18

    Receiver operating characteristic (ROC) surface analysis is usually employed to assess the accuracy of a medical diagnostic test when there are three ordered disease status (e.g. non-diseased, intermediate, diseased). In practice, verification bias can occur due to missingness of the true disease status and can lead to a distorted conclusion on diagnostic accuracy. In such situations, bias-corrected inference tools are required. This paper introduce an R package, named bcROCsurface, which provides utility functions for verification bias-corrected ROC surface analysis. The shiny web application of the correction for verification bias in estimation of the ROC surface analysis is also developed. bcROCsurface may become an important tool for the statistical evaluation of three-class diagnostic markers in presence of verification bias. The R package, readme and example data are available on CRAN. The web interface enables users less familiar with R to evaluate the accuracy of diagnostic tests, and can be found at http://khanhtoduc.shinyapps.io/bcROCsurface_shiny/ .

  7. High-volume natural volcanic pozzolan and limestone powder as partial replacements for portland cement in self-compacting and sustainable concrete

    KAUST Repository

    Celik, Kemal; Jackson, Marie D.; Mancio, Mauricio; Meral, Cagla; Emwas, Abdul-Hamid M.; Mehta, P. Kumar; Monteiro, Paulo José Meleragno

    2014-01-01

    A laboratory study demonstrates that high volume, 45% by mass replacement of portland cement (OPC) with 30% finely-ground basaltic ash from Saudi Arabia (NP) and 15% limestone powder (LS) produces concrete with good workability, high 28-day compressive strength (39 MPa), excellent one year strength (57 MPa), and very high resistance to chloride penetration. Conventional OPC is produced by intergrinding 95% portland clinker and 5% gypsum, and its clinker factor (CF) thus equals 0.95. With 30% NP and 15% LS portland clinker replacement, the CF of the blended ternary PC equals 0.52 so that 48% CO2 emissions could be avoided, while enhancing strength development and durability in the resulting self-compacting concrete (SCC). Petrographic and scanning electron microscopy (SEM) investigations of the crushed NP and finely-ground NP in the concretes provide new insights into the heterogeneous fine-scale cementitious hydration products associated with basaltic ash-portland cement reactions. © 2013 Published by Elsevier Ltd.

  8. Bound states on the lattice with partially twisted boundary conditions

    International Nuclear Information System (INIS)

    Agadjanov, D.; Guo, F.-K.; Ríos, G.; Rusetsky, A.

    2015-01-01

    We propose a method to study the nature of exotic hadrons by determining the wave function renormalization constant Z from lattice simulations. It is shown that, instead of studying the volume-dependence of the spectrum, one may investigate the dependence of the spectrum on the twisting angle, imposing twisted boundary conditions on the fermion fields on the lattice. In certain cases, e.g., the case of the DK bound state which is addressed in detail, it is demonstrated that the partial twisting is equivalent to the full twisting up to exponentially small corrections.

  9. Publisher Correction

    DEFF Research Database (Denmark)

    Turcot, Valérie; Lu, Yingchang; Highland, Heather M

    2018-01-01

    In the published version of this paper, the name of author Emanuele Di Angelantonio was misspelled. This error has now been corrected in the HTML and PDF versions of the article.......In the published version of this paper, the name of author Emanuele Di Angelantonio was misspelled. This error has now been corrected in the HTML and PDF versions of the article....

  10. Author Correction

    DEFF Research Database (Denmark)

    Grundle, D S; Löscher, C R; Krahmann, G

    2018-01-01

    A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has not been fixed in the paper.......A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has not been fixed in the paper....

  11. Partial twisting for scalar mesons

    International Nuclear Information System (INIS)

    Agadjanov, Dimitri; Meißner, Ulf-G.; Rusetsky, Akaki

    2014-01-01

    The possibility of imposing partially twisted boundary conditions is investigated for the scalar sector of lattice QCD. According to the commonly shared belief, the presence of quark-antiquark annihilation diagrams in the intermediate state generally hinders the use of the partial twisting. Using effective field theory techniques in a finite volume, and studying the scalar sector of QCD with total isospin I=1, we however demonstrate that partial twisting can still be performed, despite the fact that annihilation diagrams are present. The reason for this are delicate cancellations, which emerge due to the graded symmetry in partially quenched QCD with valence, sea and ghost quarks. The modified Lüscher equation in case of partial twisting is given

  12. Anatomic partial nephrectomy: technique evolution.

    Science.gov (United States)

    Azhar, Raed A; Metcalfe, Charles; Gill, Inderbir S

    2015-03-01

    Partial nephrectomy provides equivalent long-term oncologic and superior functional outcomes as radical nephrectomy for T1a renal masses. Herein, we review the various vascular clamping techniques employed during minimally invasive partial nephrectomy, describe the evolution of our partial nephrectomy technique and provide an update on contemporary thinking about the impact of ischemia on renal function. Recently, partial nephrectomy surgical technique has shifted away from main artery clamping and towards minimizing/eliminating global renal ischemia during partial nephrectomy. Supported by high-fidelity three-dimensional imaging, novel anatomic-based partial nephrectomy techniques have recently been developed, wherein partial nephrectomy can now be performed with segmental, minimal or zero global ischemia to the renal remnant. Sequential innovations have included early unclamping, segmental clamping, super-selective clamping and now culminating in anatomic zero-ischemia surgery. By eliminating 'under-the-gun' time pressure of ischemia for the surgeon, these techniques allow an unhurried, tightly contoured tumour excision with point-specific sutured haemostasis. Recent data indicate that zero-ischemia partial nephrectomy may provide better functional outcomes by minimizing/eliminating global ischemia and preserving greater vascularized kidney volume. Contemporary partial nephrectomy includes a spectrum of surgical techniques ranging from conventional-clamped to novel zero-ischemia approaches. Technique selection should be tailored to each individual case on the basis of tumour characteristics, surgical feasibility, surgeon experience, patient demographics and baseline renal function.

  13. Partial differential equations

    CERN Document Server

    Sloan, D; Süli, E

    2001-01-01

    /homepage/sac/cam/na2000/index.html7-Volume Set now available at special set price ! Over the second half of the 20th century the subject area loosely referred to as numerical analysis of partial differential equations (PDEs) has undergone unprecedented development. At its practical end, the vigorous growth and steady diversification of the field were stimulated by the demand for accurate and reliable tools for computational modelling in physical sciences and engineering, and by the rapid development of computer hardware and architecture. At the more theoretical end, the analytical insight in

  14. 293.15 K到333.15 K温度下一些氨基酸及其相应基团水溶液中的偏摩尔体积研究%Studies on Partial Molar Volumes of Some Amino Acids and Their Groups in Aqueous Solutions from 293.15 K to 333.15 K

    Institute of Scientific and Technical Information of China (English)

    赵长伟; 马沛生; 夏淑倩

    2004-01-01

    Densities of aqueous solutions of eight amino acids, glycine, L-alanine, L-valine, L-isoleucine, L-serine,L-threonine, L-arginine and L-phenylalanine, are measured as a function of amino acid concentration from 293.15 K to 333.15K. These data are used to calculate the apparent molar volume V and infinite dilution apparent molar volume V0 (partial molar volume). Data of five amino acids are used to correlate partial molar volume V0 using group contribution method to estimate the contributions of the zwitterionic end groups (NH3+,COO-) and CH2group, OH group, CNHNHNH2 group and C6H5(phenyl) group of amino acids. The results show that V0 values for all kinds of groups of amino acids studied increase with increase of temperature except those for CH2 group,which are almost constant within the studied temperature range. Data of other amino acids, L-valine, L-isoleucine and L-threonine, are chosen for comparison with the predicted partial molar volume V0 using the group additivity parameters obtained. The results confirm that this group additivity method has excellent predictive utility.

  15. Publisher Correction

    DEFF Research Database (Denmark)

    Stokholm, Jakob; Blaser, Martin J.; Thorsen, Jonathan

    2018-01-01

    The originally published version of this Article contained an incorrect version of Figure 3 that was introduced following peer review and inadvertently not corrected during the production process. Both versions contain the same set of abundance data, but the incorrect version has the children...

  16. Publisher Correction

    DEFF Research Database (Denmark)

    Flachsbart, Friederike; Dose, Janina; Gentschew, Liljana

    2018-01-01

    The original version of this Article contained an error in the spelling of the author Robert Häsler, which was incorrectly given as Robert Häesler. This has now been corrected in both the PDF and HTML versions of the Article....

  17. Correction to

    DEFF Research Database (Denmark)

    Roehle, Robert; Wieske, Viktoria; Schuetz, Georg M

    2018-01-01

    The original version of this article, published on 19 March 2018, unfortunately contained a mistake. The following correction has therefore been made in the original: The names of the authors Philipp A. Kaufmann, Ronny Ralf Buechel and Bernhard A. Herzog were presented incorrectly....

  18. The usefulness and the problems of attenuation correction using simultaneous transmission and emission data acquisition method. Studies on normal volunteers and phantom

    International Nuclear Information System (INIS)

    Kijima, Tetsuji; Kumita, Shin-ichiro; Mizumura, Sunao; Cho, Keiichi; Ishihara, Makiko; Toba, Masahiro; Kumazaki, Tatsuo; Takahashi, Munehiro.

    1997-01-01

    Attenuation correction using simultaneous transmission data (TCT) and emission data (ECT) acquisition method was applied to 201 Tl myocardial SPECT with ten normal adults and the phantom in order to validate the efficacy of attenuation correction using this method. Normal adults study demonstrated improved 201 Tl accumulation to the septal wall and the posterior wall of the left ventricle and relative decreased activities in the lateral wall with attenuation correction (p 201 Tl uptake organs such as the liver and the stomach pushed up the activities in the septal wall and the posterior wall. Cardiac dynamic phantom studies showed partial volume effect due to cardiac motion contributed to under-correction of the apex, which might be overcome using gated SPECT. Although simultaneous TCT and ECT acquisition was conceived of the advantageous method for attenuation correction, miss-correction of the special myocardial segments should be taken into account in assessment of attenuation correction compensated images. (author)

  19. Partial molar volume of paracetamol in water, 0.1 M HCl and 0.154 M NaCl at T = (298.15, 303.15, 308.15 and 310.65) K and at 101.325 kPa

    Energy Technology Data Exchange (ETDEWEB)

    Iqbal, Muhammad Javed [Department of Chemistry, Quaid-i-Azam University, Islamabad, Capital 54320 (Pakistan)]. E-mail: mjiqauchem@yahoo.com; Malik, Qaisar Mahmood [Department of Chemistry, Quaid-i-Azam University, Islamabad, Capital 54320 (Pakistan)]. E-mail: qaisar_@hotmail.com

    2005-12-15

    The apparent molar volume of paracetamol (4-acetamidophenol) in water, 0.1 M HCl and 0.154 M NaCl as solvents at (298.15, 303.15, 308.15 and 310.65) K temperatures and at a pressure of 101.325 kPa were determined from the density data obtained with the help of a vibrating-tube Anton Paar DMA-48 densimeter. The partial molar volume, V {sub m}, of paracetamol in these solvents at different temperatures was evaluated by extrapolating the apparent molar volume versus molality plots to m = 0. In addition, the partial molar expansivity, E {sup .}, the isobaric coefficient of thermal expansion, {alpha} {sub p}, and the interaction coefficient, S {sub v}, have also been computed. The expansivity data show dependence of E {sup .} values on the structure of the solute molecules.

  20. Partial molar volume of paracetamol in water, 0.1 M HCl and 0.154 M NaCl at T = (298.15, 303.15, 308.15 and 310.65) K and at 101.325 kPa

    International Nuclear Information System (INIS)

    Iqbal, Muhammad Javed; Malik, Qaisar Mahmood

    2005-01-01

    The apparent molar volume of paracetamol (4-acetamidophenol) in water, 0.1 M HCl and 0.154 M NaCl as solvents at (298.15, 303.15, 308.15 and 310.65) K temperatures and at a pressure of 101.325 kPa were determined from the density data obtained with the help of a vibrating-tube Anton Paar DMA-48 densimeter. The partial molar volume, V m , of paracetamol in these solvents at different temperatures was evaluated by extrapolating the apparent molar volume versus molality plots to m = 0. In addition, the partial molar expansivity, E . , the isobaric coefficient of thermal expansion, α p , and the interaction coefficient, S v , have also been computed. The expansivity data show dependence of E . values on the structure of the solute molecules

  1. Correction: Mutsuzaki, H., et al. Improved Bonding of Partially Osteomyelitic Bone to Titanium Pins Owing to Biomimetic Coating of Apatite. Int. J. Mol. Sci. 2013, 14, 24366–24379.

    Directory of Open Access Journals (Sweden)

    Hirotaka Mutsuzaki

    2014-05-01

    Full Text Available In the original version of the manuscript [1] there was an inadvertent error. The words “25 °C for 48 h” should be replaced with “25 °C for 24 h”. The authors carried out the coating experiments at 25 °C for 1, 3, 6, 12, 24 and 48 h. The apatite coatings formed at 25 °C for 24 and 48 h were found to be identical in physicochemical nature, which was revealed by SEM, EDX, XRD and chemical analysis. Thus, in the animal experiments, the authors used apatite-coated Ti pins fabricated at 25 °C for 24 h. Several corrections are thus required in the abstract, the main text, the figure legends, and the figures (Table 1. The authors would like to apologize for any inconvenience this may have caused to readers of the journal. [...

  2. Fundamental partial compositeness

    CERN Document Server

    Sannino, Francesco

    2016-11-07

    We construct renormalizable Standard Model extensions, valid up to the Planck scale, that give a composite Higgs from a new fundamental strong force acting on fermions and scalars. Yukawa interactions of these particles with Standard Model fermions realize the partial compositeness scenario. Successful models exist because gauge quantum numbers of Standard Model fermions admit a minimal enough 'square root'. Furthermore, right-handed SM fermions have an SU(2)$_R$-like structure, yielding a custodially-protected composite Higgs. Baryon and lepton numbers arise accidentally. Standard Model fermions acquire mass at tree level, while the Higgs potential and flavor violations are generated by quantum corrections. We further discuss accidental symmetries and other dynamical features stemming from the new strongly interacting scalars. If the same phenomenology can be obtained from models without our elementary scalars, they would reappear as composite states.

  3. Fundamental partial compositeness

    International Nuclear Information System (INIS)

    Sannino, Francesco; Strumia, Alessandro; Tesi, Andrea; Vigiani, Elena

    2016-01-01

    We construct renormalizable Standard Model extensions, valid up to the Planck scale, that give a composite Higgs from a new fundamental strong force acting on fermions and scalars. Yukawa interactions of these particles with Standard Model fermions realize the partial compositeness scenario. Under certain assumptions on the dynamics of the scalars, successful models exist because gauge quantum numbers of Standard Model fermions admit a minimal enough ‘square root’. Furthermore, right-handed SM fermions have an SU(2)_R-like structure, yielding a custodially-protected composite Higgs. Baryon and lepton numbers arise accidentally. Standard Model fermions acquire mass at tree level, while the Higgs potential and flavor violations are generated by quantum corrections. We further discuss accidental symmetries and other dynamical features stemming from the new strongly interacting scalars. If the same phenomenology can be obtained from models without our elementary scalars, they would reappear as composite states.

  4. 二氧化碳与2-丁醇二元体系在高压下的亨利系数和偏摩尔体积性质计算%Calculation of Henry's coefficient and partial molar volume of carbon dioxide in 2-butanol at elevated pressures

    Institute of Scientific and Technical Information of China (English)

    田爱琴; 孙洪博; 陈文涛; 王琳

    2012-01-01

    Based on vapor-liquid phase equilibria data for CO2+2-butanol binary system from 323K to 353K by constant-volume visual high-pressure cell, the solubility model of CO2 in 2-butanol was established with Krichevsky-Kasarnovsky equation. Henry's coefficients and partial molar volumes of CO2 at infinite dilution were calculated. Meanwhile, Partial molar volumes of CO2 and 2-butanol at equilibrium were calculated from partial molar volumes properties together with Peng-Robinson equation of state and Van der Waals-2 mixed rule. The results showed that Henry's coefficients and partial molar volumes of CO2 at infinite dilution were both the function of temperature, and Henry's coefficients decreased with temperature. The partial molar volumes of CO2 at infinite dilution were negative and the magnitudes decreased with temperature. The calculated effects of partial molar volumes of vapor and liquid phase at equilibrium showed that the partial molar volumes of CO2 and 2-butanol in liquid phase were positive, but in vapor the partial molar volumes of CO2 were negative and the partial molar volumes of 2-butanol were positive. The research provided theoretical basis for deciding supercritical extraction conditions and instructing industrial production.%利用固定体积可视高压釜测量出的在323 K~353 K温度范围内的CO2与2-丁醇二元体系在高压下的汽液相平衡数据,根据Krichevsky-Kasarnovsky方程建立了CO2在液相中的溶解度模型,得到了该二元体系在高压下的亨利系数和CO2在无限稀释溶液中的偏摩尔体积等性质.同时根据偏摩尔体积性质和Peng-Robinson状态方程及Van der Waals-2混合规则来计算该体系在平衡状态下的气、液相的偏摩尔体积.结果表明CO2在2-丁醇中的亨利系数和CO2在无限稀释溶液中的偏摩尔体积均为温度的函数,CO2在2-丁醇中的亨利系数随温度的升高而降低.CO2在无限稀释溶液中的偏摩尔体积(V)1∞在研究温度下均为

  5. Corrective Jaw Surgery

    Medline Plus

    Full Text Available ... out more. Corrective Jaw Surgery Corrective Jaw Surgery Orthognathic surgery is performed to correct the misalignment of jaws ... out more. Corrective Jaw Surgery Corrective Jaw Surgery Orthognathic surgery is performed to correct the misalignment of jaws ...

  6. Elements of partial differential equations

    CERN Document Server

    Sneddon, Ian Naismith

    1957-01-01

    Geared toward students of applied rather than pure mathematics, this volume introduces elements of partial differential equations. Its focus is primarily upon finding solutions to particular equations rather than general theory.Topics include ordinary differential equations in more than two variables, partial differential equations of the first and second orders, Laplace's equation, the wave equation, and the diffusion equation. A helpful Appendix offers information on systems of surfaces, and solutions to the odd-numbered problems appear at the end of the book. Readers pursuing independent st

  7. Differentiation between focal malignant marrow-replacing lesions and benign red marrow deposition of the spine with T2*-corrected fat-signal fraction map using a three -echo volume interpolated breath-hold gradient echo dixon sequence

    International Nuclear Information System (INIS)

    Kim, Yong Pyo; Kim, Sung Jun; Chung, Tae Sub; Yoo, Yeon Hwa; Yoon, Choon Sik; Kanneengiesser, Stephan; Paek, Moon Young; Song, Ho Taek; Lee, Young Han; Suh, Jin Suck

    2014-01-01

    To assess the feasibility of T2 * -corrected fat-signal fraction (FF) map by using the three-echo volume interpolated breath-hold gradient echo (VIBE) Dixon sequence to differentiate between malignant marrow-replacing lesions and benign red marrow deposition of vertebrae. We assessed 32 lesions from 32 patients who underwent magnetic resonance imaging after being referred for assessment of a known or possible vertebral marrow abnormality. The lesions were divided into 21 malignant marrow-replacing lesions and 11 benign red marrow depositions. Three sequences for the parameter measurements were obtained by using a 1.5-T MR imaging scanner as follows: three-echo VIBE Dixon sequence for FF; conventional T1-weighted imaging for the lesion-disc ratio (LDR); pre- and post-gadolinium enhanced fat-suppressed T1-weighted images for the contrast-enhancement ratio (CER). A region of interest was drawn for each lesion for parameter measurements. The areas under the curve (AUC) of the parameters and their sensitivities and specificities at the most ideal cutoff values from receiver operating characteristic curve analysis were obtained. AUC, sensitivity, and specificity were respectively compared between FF and CER. The AUCs of FF, LDR, and CER were 0.96, 0.80, and 0.72, respectively. In the comparison of diagnostic performance between the FF and CER, the FF showed a significantly larger AUC as compared to the CER (p = 0.030), although the difference of sensitivity (p = 0.157) and specificity (p = 0.157) were not significant. Fat-signal fraction measurement using T2 * -corrected three-echo VIBE Dixon sequence is feasible and has a more accurate diagnostic performance, than the CER, in distinguishing benign red marrow deposition from malignant bone marrow-replacing lesions.

  8. NJP VOLUME 40 No 4 Corrected

    African Journals Online (AJOL)

    PROF. EZECHUKWU

    2012-12-10

    Dec 10, 2012 ... Caroli's syndrome is a rare congenital disorder that in- volves intrahepatic bile duct ectasia and congenital he- ... rare disorder and often associated with autosomal reces- sive polycystic kidney disease. ... tic kidney disease, portal hypertension and eventual liver fibrosis.6. Our patient had Calori disease ...

  9. NJP VOLUME 40 No 4 Corrected

    African Journals Online (AJOL)

    PROF. EZECHUKWU

    2013-03-06

    Mar 6, 2013 ... Studies from most parts of Africa and other developing countries ... diseases such as malaria, acute respiratory infections, diarrhoea and ..... 4. 1.7. 2.4. ***Digestive system diseases. 20. 2. 10.0. 1.2. Tetanus. 3. 2. 66.7. 1.2.

  10. NJP VOLUME 40 No 4 Corrected

    African Journals Online (AJOL)

    PROF. EZECHUKWU

    2013-03-06

    Mar 6, 2013 ... the children with mental health disorders is ... from specific child populations in Nigeria.2 Parental psychopathology, in addition to low socio economic status and ... assessment of family function and caregiver burden re- spectively.5,6 ... maternal history of the disorder, the family's socio eco- nomic status ...

  11. NJP VOLUME 40 No 4 Corrected

    African Journals Online (AJOL)

    PROF. EZECHUKWU

    2013-03-01

    Mar 1, 2013 ... heart defects (e.g Tetralogy of Fallot, Truncus arteriosus and Transposition of the great arteries) typically present with cyanosis while acyanotic heart defects (e.g Ven- tricular septal defect, Atrial septal defect, Pulmonary stenosis) do not normally manifest with cyanosis. Children with CHD have impaired ...

  12. NJP VOLUME 40 No 4 Corrected

    African Journals Online (AJOL)

    PROF. EZECHUKWU

    2013-02-13

    Feb 13, 2013 ... asthma were 77.6 SD 18.1 vs.81.1. SD15.1 (MD 3.5, ... individual with the various aspects of his or her life.1 It ... participating in sports activity or physical exercise, lift- ..... research team at Mapi Research Institute, Lyon, France.

  13. NJP VOLUME 40 No 4 Corrected

    African Journals Online (AJOL)

    PROF. EZECHUKWU

    2013-02-20

    Feb 20, 2013 ... abscess. Delay in diagnosis, appears to result from a failure to give serious consideration ... was no contact with an adult with chronic cough. Examination .... left hemithorax with minimal apical sparing with oblit- eration of the ...

  14. NJP VOLUME 40 No 4 Corrected

    African Journals Online (AJOL)

    PROF. EZECHUKWU

    2013-04-18

    Apr 18, 2013 ... hypoglycaemia in children with acute diarrhoea varied from 4.5-11.0%.4-6 This ..... caemia in causing death in children presenting with diar- rhoea. Thus, it might be .... ing neonatal hypoglycemia: work- shop report from ...

  15. NJP VOLUME 40 No 4 Corrected

    African Journals Online (AJOL)

    PROF. EZECHUKWU

    2013-05-04

    May 4, 2013 ... births and only 4% of cases are products of twin preg- nancies. The first documented case occurring in ... ily history of congenital malformations, the index preg- nancy was preceded by three successive ... Both babies were discharged home at the age of 24 days to be followed up in the clinic. However, the ...

  16. NJP VOLUME 40 No 4 Corrected

    African Journals Online (AJOL)

    PROF. EZECHUKWU

    2013-03-04

    Mar 4, 2013 ... lines for the treatment of malaria recommend the use of ... occurs 2 hours after oral intake reaching peak plasma concentration ... This rash was itchy and makes patient ... but no neurological deficits or hearing problems. The.

  17. NJP VOLUME 40 No 4 Corrected

    African Journals Online (AJOL)

    PROF. EZECHUKWU

    2013-02-15

    Feb 15, 2013 ... academic performance among school children in Port Harcourt ... of poor school performance com- pared with ... on socio-demographic data, enuresis data, and family stressors. ... economic stratification of the children was done based ..... parents, large family size and low family income acts as stressors to ...

  18. NJP VOLUME 40 No 4 Corrected

    African Journals Online (AJOL)

    PROF. EZECHUKWU

    2013-04-15

    school and 53% in school aged children.9 In Nigeria ... a major contributor to infant and under-five mortality in. Nigeria, and ... development and cognitive function during the critical years of ..... assessing vitamin A deficiency and.

  19. NJP VOLUME 40 No 4 Corrected

    African Journals Online (AJOL)

    PROF. EZECHUKWU

    2013-05-19

    May 19, 2013 ... Malnutrition and acute lower respiratory infections. (ALRI) are ... kor and marasmic-kwashiorkor), sickle cell disease, diarrhoea .... these complications, with heart failure as the single most common ... Abnormal percussion note.

  20. NJP VOLUME 40 No 4 Corrected

    African Journals Online (AJOL)

    PROF. EZECHUKWU

    2013-04-25

    Apr 25, 2013 ... decline in kidney function which clinically manifests as ... economic costs, particularly in the context of critically ..... sequent AKI is reversed in most cases if acute cortical ... when they can pay, certain logistics may be unavail-.

  1. NJP VOLUME 40 No 4 Corrected

    African Journals Online (AJOL)

    PROF. EZECHUKWU

    2013-05-25

    May 25, 2013 ... education was JSS 2 and she sells cooked food. The father, a 40-year-old army ... because of lack of necessary facilities to conduct such investigations. ... disorders accounting for 15% of birth defects, while environmental ...

  2. The partial Siberian snake experiment at the Brookhaven AGS

    International Nuclear Information System (INIS)

    Huang, H.; Caussyn, D.D.; Ellison, T.; Jones, B.; Lee, S.Y.; Schwandt, P.; Ahren, L.; Alessi, J.; Bleser, E.J.; Bunce, G.; Cameron, P.; Courant, E.D.; Foelsche, H.W.; Gardner, C.J.; Geller, J.; Lee, Y.Y.; Makdisi, Y.I.; Mane, S.R.; Ratner, L.; Reece, K.; Roser, T.; Skelly, J.F.; Soukas, A.; Tepikian, S.; Thern, R.E.; van Asselt, W.; Spinka, H.; Teng, L.; Underwood, D.G.; Yokosawa, A.; Wienands, U.; Bharadwaj, V.; Hsueh, S.; Hiramatsu, S.; Mori, Y.; Sato, H.; Yokoya, K.

    1992-01-01

    We are building a 4.7 Tesla-meter room temperature solenoid to be installed in a 10-foot long AGS straight section. This experiment will test the idea of using a partial snake to correct all depolarizing imperfection resonances and also test the feasibility of betatron tune jump in correction intrinsic resonances in the presence of a partial snake

  3. Truncation correction for oblique filtering lines

    International Nuclear Information System (INIS)

    Hoppe, Stefan; Hornegger, Joachim; Lauritsch, Guenter; Dennerlein, Frank; Noo, Frederic

    2008-01-01

    State-of-the-art filtered backprojection (FBP) algorithms often define the filtering operation to be performed along oblique filtering lines in the detector. A limited scan field of view leads to the truncation of those filtering lines, which causes artifacts in the final reconstructed volume. In contrast to the case where filtering is performed solely along the detector rows, no methods are available for the case of oblique filtering lines. In this work, the authors present two novel truncation correction methods which effectively handle data truncation in this case. Method 1 (basic approach) handles data truncation in two successive preprocessing steps by applying a hybrid data extrapolation method, which is a combination of a water cylinder extrapolation and a Gaussian extrapolation. It is independent of any specific reconstruction algorithm. Method 2 (kink approach) uses similar concepts for data extrapolation as the basic approach but needs to be integrated into the reconstruction algorithm. Experiments are presented from simulated data of the FORBILD head phantom, acquired along a partial-circle-plus-arc trajectory. The theoretically exact M-line algorithm is used for reconstruction. Although the discussion is focused on theoretically exact algorithms, the proposed truncation correction methods can be applied to any FBP algorithm that exposes oblique filtering lines.

  4. Electroweak corrections

    International Nuclear Information System (INIS)

    Beenakker, W.J.P.

    1989-01-01

    The prospect of high accuracy measurements investigating the weak interactions, which are expected to take place at the electron-positron storage ring LEP at CERN and the linear collider SCL at SLAC, offers the possibility to study also the weak quantum effects. In order to distinguish if the measured weak quantum effects lie within the margins set by the standard model and those bearing traces of new physics one had to go beyond the lowest order and also include electroweak radiative corrections (EWRC) in theoretical calculations. These higher-order corrections also can offer the possibility of getting information about two particles present in the Glashow-Salam-Weinberg model (GSW), but not discovered up till now, the top quark and the Higgs boson. In ch. 2 the GSW standard model of electroweak interactions is described. In ch. 3 some special techniques are described for determination of integrals which are responsible for numerical instabilities caused by large canceling terms encountered in the calculation of EWRC effects, and methods necessary to get hold of the extensive algebra typical for EWRC. In ch. 4 various aspects related to EWRC effects are discussed, in particular the dependence of the unknown model parameters which are the masses of the top quark and the Higgs boson. The processes which are discussed are production of heavy fermions from electron-positron annihilation and those of the fermionic decay of the Z gauge boson. (H.W.). 106 refs.; 30 figs.; 6 tabs.; schemes

  5. Ballistic deficit correction

    International Nuclear Information System (INIS)

    Duchene, G.; Moszynski, M.; Curien, D.

    1991-01-01

    The EUROGAM data-acquisition has to handle a large number of events/s. Typical in-beam experiments using heavy-ion fusion reactions assume the production of about 50 000 compound nuclei per second deexciting via particle and γ-ray emissions. The very powerful γ-ray detection of EUROGAM is expected to produce high-fold event rates as large as 10 4 events/s. Such high count rates introduce, in a common dead time mode, large dead times for the whole system associated with the processing of the pulse, its digitization and its readout (from the preamplifier pulse up to the readout of the information). In order to minimize the dead time the shaping time constant τ, usually about 3 μs for large volume Ge detectors has to be reduced. Smaller shaping times, however, will adversely affect the energy resolution due to ballistic deficit. One possible solution is to operate the linear amplifier, with a somewhat smaller shaping time constant (in the present case we choose τ = 1.5 μs), in combination with a ballistic deficit compensator. The ballistic deficit can be corrected in different ways using a Gated Integrator, a hardware correction or even a software correction. In this paper we present a comparative study of the software and hardware corrections as well as gated integration

  6. The Partial Molar Volume and Compressibility of the FeO Component in Model Basalts (Mixed CaAl2Si2O8-CaMgSi2O6-CaFeSi2O6 Liquids) at 0 GPa: evidence of Fe2+ in 6-fold coordination

    Science.gov (United States)

    Guo, X.; Lange, R. A.; Ai, Y.

    2010-12-01

    FeO is an important component in magmatic liquids and yet its partial molar volume at one bar is not as well known as that for Fe2O3 because of the difficulty of performing double-bob density measurements under reducing conditions. Moreover, there is growing evidence from spectroscopic studies that Fe2+ occurs in 4, 5, and 6-fold coordination in silicate melts, and it is expected that the partial molar volume and compressibility of the FeO component will vary accordingly. We have conducted both density and relaxed sound speed measurements on four liquids in the An-Di-Hd (CaAl2Si2O8-CaMgSi2O6-CaFeSi2O6) system: (1) Di-Hd (50:50), (2) An-Hd (50:50), (3) An-Di-Hd (33:33:33) and (4) Hd (100). Densities were measured between 1573 and 1838 K at one bar with the double-bob Archimedean method using molybdenum bobs and crucibles in a reducing gas (1%CO-99%Ar) environment. The sound speeds were measured under similar conditions with a frequency-sweep acoustic interferometer, and used to calculate isothermal compressibility. All the density data for the three multi-component (model basalt) liquids were combined with density data on SiO2-Al2O3-CaO-MgO-K2O-Na2O liquids (Lange, 1997) in a fit to a linear volume equation; the results lead to a partial molar volume (±1σ) for FeO =11.7 ± 0.3(±1σ) cm3/mol at 1723 K. This value is similar to that for crystalline FeO at 298 K (halite structure; 12.06 cm3/mol), which suggests an average Fe2+ coordination of ~6 in these model basalt compositions. In contrast, the fitted partial molar volume of FeO in pure hedenbergite liquid is 14.6 ± 0.3 at 1723 K, which is consistent with an average Fe2+ coordination of 4.3 derived from EXAFS spectroscopy (Rossano, 2000). Similarly, all the compressibility data for the three multi-component liquids were combined with compressibility data on SiO2-Al2O3-CaO-MgO liquids (Ai and Lange, 2008) in a fit to an ideal mixing model for melt compressibility; the results lead to a partial molar

  7. Practical aspects of data-driven motion correction approach for brain SPECT

    International Nuclear Information System (INIS)

    Kyme, A.Z.; Hutton, B.F.; Hatton, R.L.; Skerrett, D.; Barnden, L.

    2002-01-01

    Full text: Patient motion can cause image artifacts in SPECT despite restraining measures. Data-driven detection and correction of motion can be achieved by comparison of acquired data with the forward-projections. By optimising the orientation of a partial reconstruction, parameters can be obtained for each misaligned projection and applied to update this volume using a 3D reconstruction algorithm. Phantom validation was performed to explore practical aspects of this approach. Noisy projection datasets simulating a patient undergoing at least one fully 3D movement during acquisition were compiled from various projections of the digital Hoffman brain phantom. Motion correction was then applied to the reconstructed studies. Correction success was assessed visually and quantitatively. Resilience with respect to subset order and missing data in the reconstruction and updating stages, detector geometry considerations, and the need for implementing an iterated correction were assessed in the process. Effective correction of the corrupted studies was achieved. Visually, artifactual regions in the reconstructed slices were suppressed and/or removed. Typically the ratio of mean square difference between the corrected and reference studies compared to that between the corrupted and reference studies was > 2. Although components of the motions are missed using a single-head implementation, improvement was still evident in the correction. The need for multiple iterations in the approach was small due to the bulk of misalignment errors being corrected in the first pass. Dispersion of subsets for reconstructing and updating the partial reconstruction appears to give optimal correction. Further validation is underway using triple-head physical phantom data. Copyright (2002) The Australian and New Zealand Society of Nuclear Medicine Inc

  8. Boundary Correct Real-Time Soft Shadows

    DEFF Research Database (Denmark)

    Jacobsen, Bjarke; Christensen, Niels Jørgen; Larsen, Bent Dalgaard

    2004-01-01

    This paper describes a method to determine correct shadow boundaries from an area light source using umbra and penumbra volumes. The light source is approximated by a circular disk as this gives a fast way to extrude the volumes. The method also gives a crude estimate of the visibility of the are...... for implementation on most programmable hardware. Though some crude approximations are used in the visibility function, the method can be used to produce soft shadows with correct boundaries in real time....

  9. Partial molar volumes of organic solutes in water. XXVI. 15-Crown-5 and 18-crown-6 ethers at temperatures (298 to 573) K and pressures up to 30 MPa

    International Nuclear Information System (INIS)

    Cibulka, Ivan

    2015-01-01

    Highlights: • Density data were obtained in the range T from (298 to 573) K and p up to 30 MPa. • Standard molar volumes of two crown ethers in water are presented. • Group contribution method was designed to estimate standard molar volumes of cyclic ethers. - Abstract: Densities of dilute aqueous solutions of two cyclic ethers, viz. 15-crown-5 and 18-crown-6, measured over the temperature range from (298 to 573) K and at pressures up to 30 MPa using an automated flow vibrating-tube densimeter are reported. Standard molar volumes were evaluated from the measured data. Present data were combined with those obtained previously for several cyclic ethers and predictions of standard molar volumes based on group contribution approach were tested and analysed

  10. Partial tooth gear bearings

    Science.gov (United States)

    Vranish, John M. (Inventor)

    2010-01-01

    A partial gear bearing including an upper half, comprising peak partial teeth, and a lower, or bottom, half, comprising valley partial teeth. The upper half also has an integrated roller section between each of the peak partial teeth with a radius equal to the gear pitch radius of the radially outwardly extending peak partial teeth. Conversely, the lower half has an integrated roller section between each of the valley half teeth with a radius also equal to the gear pitch radius of the peak partial teeth. The valley partial teeth extend radially inwardly from its roller section. The peak and valley partial teeth are exactly out of phase with each other, as are the roller sections of the upper and lower halves. Essentially, the end roller bearing of the typical gear bearing has been integrated into the normal gear tooth pattern.

  11. Generalized solutions of nonlinear partial differential equations

    CERN Document Server

    Rosinger, EE

    1987-01-01

    During the last few years, several fairly systematic nonlinear theories of generalized solutions of rather arbitrary nonlinear partial differential equations have emerged. The aim of this volume is to offer the reader a sufficiently detailed introduction to two of these recent nonlinear theories which have so far contributed most to the study of generalized solutions of nonlinear partial differential equations, bringing the reader to the level of ongoing research.The essence of the two nonlinear theories presented in this volume is the observation that much of the mathematics concernin

  12. Dynamics of partial differential equations

    CERN Document Server

    Wayne, C Eugene

    2015-01-01

    This book contains two review articles on the dynamics of partial differential equations that deal with closely related topics but can be read independently. Wayne reviews recent results on the global dynamics of the two-dimensional Navier-Stokes equations. This system exhibits stable vortex solutions: the topic of Wayne's contribution is how solutions that start from arbitrary initial conditions evolve towards stable vortices. Weinstein considers the dynamics of localized states in nonlinear Schrodinger and Gross-Pitaevskii equations that describe many optical and quantum systems. In this contribution, Weinstein reviews recent bifurcations results of solitary waves, their linear and nonlinear stability properties, and results about radiation damping where waves lose energy through radiation.   The articles, written independently, are combined into one volume to showcase the tools of dynamical systems theory at work in explaining qualitative phenomena associated with two classes of partial differential equ...

  13. Essays on partial retirement

    NARCIS (Netherlands)

    Kantarci, T.

    2012-01-01

    The five essays in this dissertation address a range of topics in the micro-economic literature on partial retirement. The focus is on the labor market behavior of older age groups. The essays examine the economic and non-economic determinants of partial retirement behavior, the effect of partial

  14. First-order partial differential equations

    CERN Document Server

    Rhee, Hyun-Ku; Amundson, Neal R

    2001-01-01

    This first volume of a highly regarded two-volume text is fully usable on its own. After going over some of the preliminaries, the authors discuss mathematical models that yield first-order partial differential equations; motivations, classifications, and some methods of solution; linear and semilinear equations; chromatographic equations with finite rate expressions; homogeneous and nonhomogeneous quasilinear equations; formation and propagation of shocks; conservation equations, weak solutions, and shock layers; nonlinear equations; and variational problems. Exercises appear at the end of mo

  15. Recurrent Partial Words

    Directory of Open Access Journals (Sweden)

    Francine Blanchet-Sadri

    2011-08-01

    Full Text Available Partial words are sequences over a finite alphabet that may contain wildcard symbols, called holes, which match or are compatible with all letters; partial words without holes are said to be full words (or simply words. Given an infinite partial word w, the number of distinct full words over the alphabet that are compatible with factors of w of length n, called subwords of w, refers to a measure of complexity of infinite partial words so-called subword complexity. This measure is of particular interest because we can construct partial words with subword complexities not achievable by full words. In this paper, we consider the notion of recurrence over infinite partial words, that is, we study whether all of the finite subwords of a given infinite partial word appear infinitely often, and we establish connections between subword complexity and recurrence in this more general framework.

  16. 3Q/4Q99 Annual M-Area and Metallurgical Laboratory Hazardous Waste Management Facilities Groundwater Monitoring and Corrective-Action Report - Third and Fourth Quarters 1999 - Volumes I and II

    International Nuclear Information System (INIS)

    Chase, J.

    2000-01-01

    This report describes the groundwater monitoring and corrective-action program at the M-Area Hazardous Waste Management Facility (HWMF) and the Metallurgical Laboratory (Met Lab) HWMF at the Savannah River Site (SRS) during 1999

  17. What is the fundamental ion-specific series for anions and cations? Ion specificity in standard partial molar volumes of electrolytes and electrostriction in water and non-aqueous solvents† †Electronic supplementary information (ESI) available. See DOI: 10.1039/c7sc02691a Click here for additional data file.

    Science.gov (United States)

    Mazzini, Virginia

    2017-01-01

    The importance of electrolyte solutions cannot be overstated. Beyond the ionic strength of electrolyte solutions the specific nature of the ions present is vital in controlling a host of properties. Therefore ion specificity is fundamentally important in physical chemistry, engineering and biology. The observation that the strengths of the effect of ions often follows well established series suggests that a single predictive and quantitative description of specific-ion effects covering a wide range of systems is possible. Such a theory would revolutionise applications of physical chemistry from polymer precipitation to drug design. Current approaches to understanding specific-ion effects involve consideration of the ions themselves, the solvent and relevant interfaces and the interactions between them. Here we investigate the specific-ion effects trends of standard partial molar volumes and electrostrictive volumes of electrolytes in water and eleven non-aqueous solvents. We choose these measures as they relate to bulk properties at infinite dilution, therefore they are the simplest electrolyte systems. This is done to test the hypothesis that the ions alone exhibit a specific-ion effect series that is independent of the solvent and unrelated to surface properties. The specific-ion effects trends of standard partial molar volumes and normalised electrostrictive volumes examined in this work show a fundamental ion-specific series that is reproduced across the solvents, which is the Hofmeister series for anions and the reverse lyotropic series for cations, supporting the hypothesis. This outcome is important in demonstrating that ion specificity is observed at infinite dilution and demonstrates that the complexity observed in the manifestation of specific-ion effects in a very wide range of systems is due to perturbations of solvent, surfaces and concentration on the underlying fundamental series. This knowledge will guide a general understanding of specific

  18. Initial Clinical Experience With the Strut-Adjusted Volume Implant (SAVI) Breast Brachytherapy Device for Accelerated Partial-Breast Irradiation (APBI): First 100 Patients With More Than 1 Year of Follow-Up

    International Nuclear Information System (INIS)

    Yashar, Catheryn M.; Scanderbeg, Daniel; Kuske, Robert; Wallace, Anne; Zannis, Victor; Blair, Sarah; Grade, Emily; Swenson, Virginia H.; Quiet, Coral

    2011-01-01

    Purpose: The Strut-Adjusted Volume Implant (SAVI; Cianna Medical, Aliso Viejo, CA) is a multichannel single-entry brachytherapy device designed to allow dose modulation to minimize normal tissue dose while simultaneously maximizing target coverage. This is the first report on the initial 102 patients with nearly 2 years of median follow-up. Methods and Materials: One hundred two patients were treated at two institutions. Data were collected on eligibility and dosimetry and followed for toxicity and recurrence. Results: The median follow-up is 21 months. Overall dosimetry is outstanding (median percent of target volume receiving 90% of the prescription dose was 95.9%, volume of target receiving 150% of the prescription dose was 27.8 mL, and volume of target receiving 200% of the prescription dose was 14.0 cm 3 ). No devices were pulled prior to treatment completion. For patients with a skin bridge of less than 7 mm, the maximum median skin dose was 280 cGy (median percent of target volume receiving 90% of the prescription dose was 95.2%, volume of target receiving 150% of the prescription dose was 25.8 cm 3 and volume of target receiving 200% of the prescription dose was 12.7 mL). For patients with both chest wall and skin of less than 7 mm, the maximum median lung dose was 205 cGy with simultaneous skin dose of 272 cGy. The rate of telangiectasia was 1.9%. Grade 1 hyperpigmentation developed in 10 patients (9.8%) and Grade 2 fibrosis in 2 patients (1.9%). There were 2 symptomatic seromas and 2 cases of asymptomatic fat necrosis (1.9%). Of the patients, 27% were not eligible for MammoSite balloon brachytherapy (Hologic, Inc., Marlborough, MA) and 5% were not eligible for any balloon brachytherapy. The recurrence rate was 1%. Conclusions: The SAVI appears to safely allow an increase in eligibility for APBI over balloon brachytherapy or three-dimensional conformal radiation, highlighting the outstanding device flexibility to maximize the target dose and minimize the

  19. A novel OPC method to reduce mask volume with yield-aware dissection

    International Nuclear Information System (INIS)

    Xie Chunlei; Chen Ye; Shi Zheng

    2013-01-01

    Growing data volume of masks tremendously increases manufacture cost. The cost increase is partially due to the complicated optical proximity corrections applied on mask design. In this paper, a yield-aware dissection method is presented. Based on the recognition of yield related mask context, the dissection result provides sufficient degrees of freedom to keep fidelity on critical sites while still retaining the frugality of modified designs. Experiments show that the final mask volume using the new method is reduced to about 50% of the conventional method. (semiconductor technology)

  20. 76 FR 25177 - Determinations Concerning Need for Error Correction, Partial Approval and Partial Disapproval...

    Science.gov (United States)

    2011-05-03

    ... projects that will create jobs and otherwise benefit the state's and the nation's economy. EPA has... from Steve Spaw, Deputy Executive Director, TACB, to William B. Hathaway, Director, Air, Pesticides and...

  1. 75 FR 82429 - Determinations Concerning Need for Error Correction, Partial Approval and Partial Disapproval...

    Science.gov (United States)

    2010-12-30

    ... and residential care 6221, 6231, 6232, 6233, 6239. facilities. Personal and laundry services 8122..., 997 (6th Cir. 1993); Dun & Bradstreet Corp. v. United States Postal Service, 946 F.2d 189, 193 (2d Cir...

  2. 75 FR 82365 - Determinations Concerning Need for Error Correction, Partial Approval and Partial Disapproval...

    Science.gov (United States)

    2010-12-30

    .../nursing and 6221, 6231, 6232, 6233, 6239 residential care facilities. Personal and laundry services 8122... that is a government of a city, county, town, school district, or special district with a population of...

  3. Network topology of olivine-basalt partial melts

    Science.gov (United States)

    Skemer, Philip; Chaney, Molly M.; Emmerich, Adrienne L.; Miller, Kevin J.; Zhu, Wen-lu

    2017-07-01

    The microstructural relationship between melt and solid grains in partially molten rocks influences many physical properties, including permeability, rheology, electrical conductivity and seismic wave speeds. In this study, the connectivity of melt networks in the olivine-basalt system is explored using a systematic survey of 3-D X-ray microtomographic data. Experimentally synthesized samples with 2 and 5 vol.% melt are analysed as a series of melt tubules intersecting at nodes. Each node is characterized by a coordination number (CN), which is the number of melt tubules that intersect at that location. Statistically representative volumes are described by coordination number distributions (CND). Polyhedral grains can be packed in many configurations yielding different CNDs, however widely accepted theory predicts that systems with small dihedral angles, such as olivine-basalt, should exhibit a predominant CN of four. In this study, melt objects are identified with CN = 2-8, however more than 50 per cent are CN = 4, providing experimental verification of this theoretical prediction. A conceptual model that considers the role of heterogeneity in local grain size and melt fraction is proposed to explain the formation of nodes with CN ≠ 4. Correctly identifying the melt network topology is essential to understanding the relationship between permeability and porosity, and hence the transport properties of partial molten mantle rocks.

  4. Atomic disintegrations for partially hyperbolic diffeomorphisms

    NARCIS (Netherlands)

    Homburg, Ale Jan

    2017-01-01

    Shub and Wilkinson and Ruelle and Wilkinson studied a class of volume preserving diffeomorphisms on the three dimensional torus that are stably ergodic. The diffeomorphisms are partially hyperbolic and admit an invariant central foliation of circles. The foliation is not absolutely continuous; in

  5. Corrective Jaw Surgery

    Medline Plus

    Full Text Available ... and Craniofacial Surgery Cleft Lip/Palate and Craniofacial Surgery A cleft lip may require one or more ... find out more. Corrective Jaw Surgery Corrective Jaw Surgery Orthognathic surgery is performed to correct the misalignment ...

  6. 1Q/2Q00 M-Area and Metallurgical Laboratory Hazardous Waste Management Facilities Groundwater Monitoring and Corrective-Action Report - First and Second Quarters 2000 - Volumes I, II, and II

    Energy Technology Data Exchange (ETDEWEB)

    Chase, J.

    2000-10-24

    This report describes the groundwater monitoring and corrective-action program at the M-Area Hazardous Waste Management Facility (HWMF) and the Metallurgical Laboratory (Met Lab) HWMF at the Savannah River site (SRS) during first and second quarters of 2000.

  7. 1Q/2Q00 M-Area and Metallurgical Laboratory Hazardous Waste Management Facilities Groundwater Monitoring and Corrective-Action Report - First and Second Quarters 2000 - Volumes I, II, and II

    International Nuclear Information System (INIS)

    Chase, J.

    2000-01-01

    This report describes the groundwater monitoring and corrective-action program at the M-Area Hazardous Waste Management Facility (HWMF) and the Metallurgical Laboratory (Met Lab) HWMF at the Savannah River site (SRS) during first and second quarters of 2000

  8. Compatriot partiality and cosmopolitan justice: Can we justify compatriot partiality within the cosmopolitan framework?

    Directory of Open Access Journals (Sweden)

    Rachelle Bascara

    2016-10-01

    Full Text Available This paper shows an alternative way in which compatriot partiality could be justified within the framework of global distributive justice. Philosophers who argue that compatriot partiality is similar to racial partiality capture something correct about compatriot partiality. However, the analogy should not lead us to comprehensively reject compatriot partiality. We can justify compatriot partiality on the same grounds that liberation movements and affirmative action have been justified. Hence, given cosmopolitan demands of justice, special consideration for the economic well-being of your nation as a whole is justified if and only if the country it identifies is an oppressed developing nation in an unjust global order.This justification is incomplete. We also need to say why Person A, qua national of Country A, is justified in helping her compatriots in Country A over similarly or slightly more oppressed non-compatriots in Country B. I argue that Person A’s partiality towards her compatriots admits further vindication because it is part of an oppressed group’s project of self-emancipation, which is preferable to paternalistic emancipation.Finally, I identify three benefits in my justification for compatriot partiality. First, I do not offer a blanket justification for all forms of compatriot partiality. Partiality between members of oppressed groups is only a temporary effective measure designed to level an unlevel playing field. Second, because history attests that sovereign republics could arise as a collective response to colonial oppression, justifying compatriot partiality on the grounds that I have identified is conducive to the development of sovereignty and even democracy in poor countries, thereby avoiding problems of infringement that many humanitarian poverty alleviation efforts encounter. Finally, my justification for compatriot partiality complies with the implicit cosmopolitan commitment to the realizability of global justice

  9. Towards quantitative PET/MRI: a review of MR-based attenuation correction techniques.

    Science.gov (United States)

    Hofmann, Matthias; Pichler, Bernd; Schölkopf, Bernhard; Beyer, Thomas

    2009-03-01

    Positron emission tomography (PET) is a fully quantitative technology for imaging metabolic pathways and dynamic processes in vivo. Attenuation correction of raw PET data is a prerequisite for quantification and is typically based on separate transmission measurements. In PET/CT attenuation correction, however, is performed routinely based on the available CT transmission data. Recently, combined PET/magnetic resonance (MR) has been proposed as a viable alternative to PET/CT. Current concepts of PET/MRI do not include CT-like transmission sources and, therefore, alternative methods of PET attenuation correction must be found. This article reviews existing approaches to MR-based attenuation correction (MR-AC). Most groups have proposed MR-AC algorithms for brain PET studies and more recently also for torso PET/MR imaging. Most MR-AC strategies require the use of complementary MR and transmission images, or morphology templates generated from transmission images. We review and discuss these algorithms and point out challenges for using MR-AC in clinical routine. MR-AC is work-in-progress with potentially promising results from a template-based approach applicable to both brain and torso imaging. While efforts are ongoing in making clinically viable MR-AC fully automatic, further studies are required to realize the potential benefits of MR-based motion compensation and partial volume correction of the PET data.

  10. Towards quantitative PET/MRI: a review of MR-based attenuation correction techniques

    International Nuclear Information System (INIS)

    Hofmann, Matthias; Pichler, Bernd; Schoelkopf, Bernhard; Beyer, Thomas

    2009-01-01

    Positron emission tomography (PET) is a fully quantitative technology for imaging metabolic pathways and dynamic processes in vivo. Attenuation correction of raw PET data is a prerequisite for quantification and is typically based on separate transmission measurements. In PET/CT attenuation correction, however, is performed routinely based on the available CT transmission data. Recently, combined PET/magnetic resonance (MR) has been proposed as a viable alternative to PET/CT. Current concepts of PET/MRI do not include CT-like transmission sources and, therefore, alternative methods of PET attenuation correction must be found. This article reviews existing approaches to MR-based attenuation correction (MR-AC). Most groups have proposed MR-AC algorithms for brain PET studies and more recently also for torso PET/MR imaging. Most MR-AC strategies require the use of complementary MR and transmission images, or morphology templates generated from transmission images. We review and discuss these algorithms and point out challenges for using MR-AC in clinical routine. MR-AC is work-in-progress with potentially promising results from a template-based approach applicable to both brain and torso imaging. While efforts are ongoing in making clinically viable MR-AC fully automatic, further studies are required to realize the potential benefits of MR-based motion compensation and partial volume correction of the PET data. (orig.)

  11. Towards quantitative PET/MRI: a review of MR-based attenuation correction techniques

    Energy Technology Data Exchange (ETDEWEB)

    Hofmann, Matthias [Max Planck Institute for Biological Cybernetics, Tuebingen (Germany); University of Tuebingen, Laboratory for Preclinical Imaging and Imaging Technology of the Werner Siemens-Foundation, Department of Radiology, Tuebingen (Germany); University of Oxford, Wolfson Medical Vision Laboratory, Department of Engineering Science, Oxford (United Kingdom); Pichler, Bernd [University of Tuebingen, Laboratory for Preclinical Imaging and Imaging Technology of the Werner Siemens-Foundation, Department of Radiology, Tuebingen (Germany); Schoelkopf, Bernhard [Max Planck Institute for Biological Cybernetics, Tuebingen (Germany); Beyer, Thomas [University Hospital Duisburg-Essen, Department of Nuclear Medicine, Essen (Germany); Cmi-Experts GmbH, Zurich (Switzerland)

    2009-03-15

    Positron emission tomography (PET) is a fully quantitative technology for imaging metabolic pathways and dynamic processes in vivo. Attenuation correction of raw PET data is a prerequisite for quantification and is typically based on separate transmission measurements. In PET/CT attenuation correction, however, is performed routinely based on the available CT transmission data. Recently, combined PET/magnetic resonance (MR) has been proposed as a viable alternative to PET/CT. Current concepts of PET/MRI do not include CT-like transmission sources and, therefore, alternative methods of PET attenuation correction must be found. This article reviews existing approaches to MR-based attenuation correction (MR-AC). Most groups have proposed MR-AC algorithms for brain PET studies and more recently also for torso PET/MR imaging. Most MR-AC strategies require the use of complementary MR and transmission images, or morphology templates generated from transmission images. We review and discuss these algorithms and point out challenges for using MR-AC in clinical routine. MR-AC is work-in-progress with potentially promising results from a template-based approach applicable to both brain and torso imaging. While efforts are ongoing in making clinically viable MR-AC fully automatic, further studies are required to realize the potential benefits of MR-based motion compensation and partial volume correction of the PET data. (orig.)

  12. Hyperbolic partial differential equations

    CERN Document Server

    Witten, Matthew

    1986-01-01

    Hyperbolic Partial Differential Equations III is a refereed journal issue that explores the applications, theory, and/or applied methods related to hyperbolic partial differential equations, or problems arising out of hyperbolic partial differential equations, in any area of research. This journal issue is interested in all types of articles in terms of review, mini-monograph, standard study, or short communication. Some studies presented in this journal include discretization of ideal fluid dynamics in the Eulerian representation; a Riemann problem in gas dynamics with bifurcation; periodic M

  13. Successful removable partial dentures.

    Science.gov (United States)

    Lynch, Christopher D

    2012-03-01

    Removable partial dentures (RPDs) remain a mainstay of prosthodontic care for partially dentate patients. Appropriately designed, they can restore masticatory efficiency, improve aesthetics and speech, and help secure overall oral health. However, challenges remain in providing such treatments, including maintaining adequate plaque control, achieving adequate retention, and facilitating patient tolerance. The aim of this paper is to review the successful provision of RPDs. Removable partial dentures are a successful form of treatment for replacing missing teeth, and can be successfully provided with appropriate design and fabrication concepts in mind.

  14. Beginning partial differential equations

    CERN Document Server

    O'Neil, Peter V

    2011-01-01

    A rigorous, yet accessible, introduction to partial differential equations-updated in a valuable new edition Beginning Partial Differential Equations, Second Edition provides a comprehensive introduction to partial differential equations (PDEs) with a special focus on the significance of characteristics, solutions by Fourier series, integrals and transforms, properties and physical interpretations of solutions, and a transition to the modern function space approach to PDEs. With its breadth of coverage, this new edition continues to present a broad introduction to the field, while also addres

  15. Chiral and continuum extrapolation of partially quenched lattice results

    Energy Technology Data Exchange (ETDEWEB)

    C.R. Allton; W. Armour; D.B. Leinweber; A.W. Thomas; R.D. Young

    2005-04-01

    The vector meson mass is extracted from a large sample of partially quenched, two-flavor lattice QCD simulations. For the first time, discretization, finite-volume and partial quenching artifacts are treated in a unified chiral effective field theory analysis of the lattice simulation results.

  16. Topics in numerical partial differential equations and scientific computing

    CERN Document Server

    2016-01-01

    Numerical partial differential equations (PDEs) are an important part of numerical simulation, the third component of the modern methodology for science and engineering, besides the traditional theory and experiment. This volume contains papers that originated with the collaborative research of the teams that participated in the IMA Workshop for Women in Applied Mathematics: Numerical Partial Differential Equations and Scientific Computing in August 2014.

  17. The theory and measurement of partial discharge transients

    DEFF Research Database (Denmark)

    Pedersen, Aage; Crichton, George C; McAllister, Iain Wilson

    1991-01-01

    A theoretical approach to partial discharge transients is presented. This approach is based on the relationship between the charge induced on the measurement electrode by those created in the interelectrode volume during partial discharge activity. The primary sources for these induced charges ar...... electrode systems of practical interest is illustrated. A discussion of the salient features and practical aspects of the theory is included...

  18. Estimation of vapour pressure and partial pressure of subliming ...

    Indian Academy of Sciences (India)

    Administrator

    conditions of (total) pressure by using thermogravimetry under those conditions. Further, from the partial pressure P, it is possible to determine the number of moles of material in the vapour phase using the ideal gas equation, PV = nRT, where P is the partial pressure, V the volume, n number of moles (of the vapour), R the ...

  19. Correction to toporek (2014).

    Science.gov (United States)

    2015-01-01

    Reports an error in "Pedagogy of the privileged: Review of Deconstructing Privilege: Teaching and Learning as Allies in the Classroom" by Rebecca L. Toporek (Cultural Diversity and Ethnic Minority Psychology, 2014[Oct], Vol 20[4], 621-622). This article was originally published online incorrectly as a Brief Report. The article authored by Rebecca L. Toporek has been published correctly as a Book Review in the October 2014 print publication (Vol. 20, No. 4, pp. 621-622. http://dx.doi.org/10.1037/a0036529). (The following abstract of the original article appeared in record 2014-42484-006.) Reviews the book, Deconstructing Privilege: Teaching and Learning as Allies in the Classroom edited by Kim A. Case (2013). The purpose of this book is to provide a collection of resources for those teaching about privilege directly, much of this volume may be useful for expanding the context within which educators teach all aspects of psychology. Understanding the history and systems of psychology, clinical practice, research methods, assessment, and all the core areas of psychology could be enhanced by consideration of the structural framework through which psychology has developed and is maintained. The book presents a useful guide for educators, and in particular, those who teach about systems of oppression and privilege directly. For psychologists, this guide provides scholarship and concrete strategies for facilitating students' awareness of multiple dimensions of privilege across content areas. (PsycINFO Database Record (c) 2015 APA, all rights reserved).

  20. Radiation protection: A correction

    International Nuclear Information System (INIS)

    1972-01-01

    An error in translation inadvertently distorted the sense of a paragraph in the article entitled 'Ecological Aspects of Radiation Protection', by Dr. P. Recht, which appeared in the Bulletin, Volume 14, No. 2 earlier this year. In the English text the error appears on Page 28, second paragraph, which reads, as published: 'An instance familiar to radiation protection specialists, which has since come to be regarded as a classic illustration of this approach, is the accidental release at the Windscale nuclear centre in the north of England.' In the French original of this text no reference was made, or intended, to the accidental release which took place in 1957; the reference was to the study of the critical population group exposed to routine releases from the centre, as the footnote made clear. A more correct translation of the relevant sentence reads: 'A classic example of this approach, well-known to radiation protection specialists, is that of releases from the Windscale nuclear centre, in the north of England.' A second error appeared in the footnote already referred to. In all languages, the critical population group studied in respect of the Windscale releases is named as that of Cornwall; the reference should be, of course, to that part of the population of Wales who eat laver bread. (author)

  1. Partial knee replacement - slideshow

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/presentations/100225.htm Partial knee replacement - series—Normal anatomy To use the sharing ... A.M. Editorial team. Related MedlinePlus Health Topics Knee Replacement A.D.A.M., Inc. is accredited ...

  2. Beginning partial differential equations

    CERN Document Server

    O'Neil, Peter V

    2014-01-01

    A broad introduction to PDEs with an emphasis on specialized topics and applications occurring in a variety of fields Featuring a thoroughly revised presentation of topics, Beginning Partial Differential Equations, Third Edition provides a challenging, yet accessible,combination of techniques, applications, and introductory theory on the subjectof partial differential equations. The new edition offers nonstandard coverageon material including Burger's equation, the telegraph equation, damped wavemotion, and the use of characteristics to solve nonhomogeneous problems. The Third Edition is or

  3. Partial gravity - Human impacts on facility design

    Science.gov (United States)

    Capps, Stephen; Moore, Nathan

    1990-01-01

    Partial gravity affects the body differently than earth gravity and microgravity environments. The main difference from earth gravity is human locomotion; while the main dfference from microgravity is the specific updown orientation and reach envelopes which increase volume requirements. Much data are available on earth gravity and microgravity design; however, very little information is available on human reactions to reduced gravity levels in IVA situations (without pressure suits). Therefore, if humans commit to permanent lunar habitation, much research should be conducted in the area of partial gravity effects on habitat design.

  4. Partially massless graviton on beyond Einstein spacetimes

    Science.gov (United States)

    Bernard, Laura; Deffayet, Cédric; Hinterbichler, Kurt; von Strauss, Mikael

    2017-06-01

    We show that a partially massless graviton can propagate on a large set of spacetimes which are not Einstein spacetimes. Starting from a recently constructed theory for a massive graviton that propagates the correct number of degrees of freedom on an arbitrary spacetime, we first give the full explicit form of the scalar constraint responsible for the absence of a sixth degree of freedom. We then spell out generic conditions for the constraint to be identically satisfied, so that there is a scalar gauge symmetry which makes the graviton partially massless. These simplify if one assumes that spacetime is Ricci symmetric. Under this assumption, we find explicit non-Einstein spacetimes (some, but not all, with vanishing Bach tensors) allowing for the propagation of a partially massless graviton. These include in particular the Einstein static Universe.

  5. Volume ventricular esquerdo crítico na estenose aórtica no primeiro ano de vida: sua importância na seleção de pacientes candidatos à correção univentricular pós-valvotomia Critical left ventricular volume in aortic stenosis in first year of life: its importance in patients selection candidates to univentricular surgical correction pos-valvotomy

    Directory of Open Access Journals (Sweden)

    Marco Aurélio Santos

    2005-09-01

    Full Text Available OBJETIVO: Análise do volume diastólico final ventricular esquerdo crítico, definido como o menor volume aceitável para a manutenção do débito cardíaco, na seleção de pacientes com estenose aórtica pós-valvotomia, candidatos à correção univentricular. MÉTODOS: Estudo retrospectivo em 21 pacientes com estenose aórtica, durante o primeiro ano de vida, e 232 compilados da literatura. Arbitraram-se como normais os valores do volume diastólico final (VDF de 20 a 60 ml/m2. Foi comparado o VDF dos grupos que foram ao óbito com aqueles que sobreviveram. Procurou-se, também, estabelecer uma correlação da idade e volume ventricular, na época da valvotomia, entre os grupos. Por fim, determinou-se o VDF esquerdo crítico, obtido através de uma relação teórica entre o VDF esquerdo e freqüência cardíaca para diferentes frações de ejeção e determinados índices cardíacos (IC: 2.000 e 2.500 ml/min/m2. RESULTADOS: Para valores do VDF 60 ml/m2, houve significância estatística entre os mortos e os sobreviventes (pOBJECTIVE: Analysis of critical end diastolic left ventricular volume (EDLVV, defined as the lowest acceptable volume to keep cardiac output, in the selection of patients with post-valvotomy aortic stenosis, candidates to univentricular correction. METHODS: A retrospective study in 21 patients with aortic stenosis, during the first year of life, and 232 patients compiled from literature. Values of end diastolic volume (EDLVV, from 20 to 60 ml/m2 were determined as normal. The EDLVV of deceased patients was compared to that from survival patients. A correlation between the age and EDLVV was carried out at the time of valvotomy, between the groups. Finally, the critical EDLVV through the theoretical relationship between the EDLVV and heart rate for different ejection fractions and designated cardiac indexes (CI: 2,000 and 2,500 20-60 ml/min/m2 was determined. RESULTS: For EDLVV values 60 ml/m2, there was statistical

  6. NWS Corrections to Observations

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Form B-14 is the National Weather Service form entitled 'Notice of Corrections to Weather Records.' The forms are used to make corrections to observations on forms...

  7. Corrective Jaw Surgery

    Medline Plus

    Full Text Available ... more surgeries depending on the extent of the repair needed. Click here to find out more. Corrective ... more surgeries depending on the extent of the repair needed. Click here to find out more. Corrective ...

  8. Corrective Jaw Surgery

    Medline Plus

    Full Text Available ... Jaw Surgery Download Download the ebook for further information Corrective jaw, or orthognathic surgery is performed by ... your treatment. Correction of Common Dentofacial Deformities ​ ​ The information provided here is not intended as a substitute ...

  9. Effects of MRI Protocol Parameters, Preload Injection Dose, Fractionation Strategies, and Leakage Correction Algorithms on the Fidelity of Dynamic-Susceptibility Contrast MRI Estimates of Relative Cerebral Blood Volume in Gliomas.

    Science.gov (United States)

    Leu, K; Boxerman, J L; Ellingson, B M

    2017-03-01

    DSC perfusion MR imaging assumes that the contrast agent remains intravascular; thus, disruptions in the blood-brain barrier common in brain tumors can lead to errors in the estimation of relative CBV. Acquisition strategies, including the choice of flip angle, TE, TR, and preload dose and incubation time, along with post hoc leakage-correction algorithms, have been proposed as means for combating these leakage effects. In the current study, we used DSC-MR imaging simulations to examine the influence of these various acquisition parameters and leakage-correction strategies on the faithful estimation of CBV. DSC-MR imaging simulations were performed in 250 tumors with perfusion characteristics randomly generated from the distributions of real tumor population data, and comparison of leakage-corrected CBV was performed with a theoretic curve with no permeability. Optimal strategies were determined by protocol with the lowest mean error. The following acquisition strategies (flip angle/TE/TR and contrast dose allocation for preload and bolus) produced high CBV fidelity, as measured by the percentage difference from a hypothetic tumor with no leakage: 1) 35°/35 ms/1.5 seconds with no preload and full dose for DSC-MR imaging, 2) 35°/25 ms/1.5 seconds with ¼ dose preload and ¾ dose bolus, 3) 60°/35 ms/2.0 seconds with ½ dose preload and ½ dose bolus, and 4) 60°/35 ms/1.0 second with 1 dose preload and 1 dose bolus. Results suggest that a variety of strategies can yield similarly high fidelity in CBV estimation, namely those that balance T1- and T2*-relaxation effects due to contrast agent extravasation. © 2017 by American Journal of Neuroradiology.

  10. Stochastic partial differential equations an introduction

    CERN Document Server

    Liu, Wei

    2015-01-01

    This book provides an introduction to the theory of stochastic partial differential equations (SPDEs) of evolutionary type. SPDEs are one of the main research directions in probability theory with several wide ranging applications. Many types of dynamics with stochastic influence in nature or man-made complex systems can be modelled by such equations. The theory of SPDEs is based both on the theory of deterministic partial differential equations, as well as on modern stochastic analysis. Whilst this volume mainly follows the ‘variational approach’, it also contains a short account on the ‘semigroup (or mild solution) approach’. In particular, the volume contains a complete presentation of the main existence and uniqueness results in the case of locally monotone coefficients. Various types of generalized coercivity conditions are shown to guarantee non-explosion, but also a systematic approach to treat SPDEs with explosion in finite time is developed. It is, so far, the only book where the latter and t...

  11. Partial differential equations

    CERN Document Server

    Evans, Lawrence C

    2010-01-01

    This text gives a comprehensive survey of modern techniques in the theoretical study of partial differential equations (PDEs) with particular emphasis on nonlinear equations. The exposition is divided into three parts: representation formulas for solutions; theory for linear partial differential equations; and theory for nonlinear partial differential equations. Included are complete treatments of the method of characteristics; energy methods within Sobolev spaces; regularity for second-order elliptic, parabolic, and hyperbolic equations; maximum principles; the multidimensional calculus of variations; viscosity solutions of Hamilton-Jacobi equations; shock waves and entropy criteria for conservation laws; and, much more.The author summarizes the relevant mathematics required to understand current research in PDEs, especially nonlinear PDEs. While he has reworked and simplified much of the classical theory (particularly the method of characteristics), he primarily emphasizes the modern interplay between funct...

  12. Correct-by-design output feedback of LTI systems

    NARCIS (Netherlands)

    Haesaert, S.; Abate, A.; van den Hof, P.M.J.

    2016-01-01

    Current state-of-the-art correct-by-design controllers are designed for full-state measurable systems. This work extends the applicability of correct-by-design controllers to partially observable linear, time-invariant (LTI) models. Towards the certification of the synthesised controllers,

  13. Optimization of partial search

    International Nuclear Information System (INIS)

    Korepin, Vladimir E

    2005-01-01

    A quantum Grover search algorithm can find a target item in a database faster than any classical algorithm. One can trade accuracy for speed and find a part of the database (a block) containing the target item even faster; this is partial search. A partial search algorithm was recently suggested by Grover and Radhakrishnan. Here we optimize it. Efficiency of the search algorithm is measured by the number of queries to the oracle. The author suggests a new version of the Grover-Radhakrishnan algorithm which uses a minimal number of such queries. The algorithm can run on the same hardware that is used for the usual Grover algorithm. (letter to the editor)

  14. Electroweak corrections to H->ZZ/WW->4 leptons

    International Nuclear Information System (INIS)

    Bredenstein, A.; Denner, A.; Dittmaier, S.; Weber, M.M.

    2006-01-01

    We provide predictions for the decays H->ZZ->4-bar and H->WW->4-bar including the complete electroweak O(α) corrections and improvements by higher-order final-state radiation and two-loop corrections proportional to G μ 2 M H 4 . The gauge-boson resonances are described in the complex-mass scheme. We find corrections at the level of 1-8% for the partial widths

  15. Self-consistency corrections in effective-interaction calculations

    International Nuclear Information System (INIS)

    Starkand, Y.; Kirson, M.W.

    1975-01-01

    Large-matrix extended-shell-model calculations are used to compute self-consistency corrections to the effective interaction and to the linked-cluster effective interaction. The corrections are found to be numerically significant and to affect the rate of convergence of the corresponding perturbation series. The influence of various partial corrections is tested. It is concluded that self-consistency is an important effect in determining the effective interaction and improving the rate of convergence. (author)

  16. Effects of image distortion correction on voxel-based morphometry

    International Nuclear Information System (INIS)

    Goto, Masami; Abe, Osamu; Kabasawa, Hiroyuki

    2012-01-01

    We aimed to show that correcting image distortion significantly affects brain volumetry using voxel-based morphometry (VBM) and to assess whether the processing of distortion correction reduces system dependency. We obtained contiguous sagittal T 1 -weighted images of the brain from 22 healthy participants using 1.5- and 3-tesla magnetic resonance (MR) scanners, preprocessed images using Statistical Parametric Mapping 5, and tested the relation between distortion correction and brain volume using VBM. Local brain volume significantly increased or decreased on corrected images compared with uncorrected images. In addition, the method used to correct image distortion for gradient nonlinearity produced fewer volumetric errors from MR system variation. This is the first VBM study to show more precise volumetry using VBM with corrected images. These results indicate that multi-scanner or multi-site imaging trials require correction for distortion induced by gradient nonlinearity. (author)

  17. Auxiliary partial liver transplantation

    NARCIS (Netherlands)

    C.B. Reuvers (Cornelis Bastiaan)

    1986-01-01

    textabstractIn this thesis studies on auxiliary partial liver transplantation in the dog and the pig are reported. The motive to perform this study was the fact that patients with acute hepatic failure or end-stage chronic liver disease are often considered to form too great a risk for successful

  18. Partial Remission Definition

    DEFF Research Database (Denmark)

    Andersen, Marie Louise Max; Hougaard, Philip; Pörksen, Sven

    2014-01-01

    OBJECTIVE: To validate the partial remission (PR) definition based on insulin dose-adjusted HbA1c (IDAA1c). SUBJECTS AND METHODS: The IDAA1c was developed using data in 251 children from the European Hvidoere cohort. For validation, 129 children from a Danish cohort were followed from the onset...

  19. Fundamental partial compositeness

    DEFF Research Database (Denmark)

    Sannino, Francesco; Strumia, Alessandro; Tesi, Andrea

    2016-01-01

    We construct renormalizable Standard Model extensions, valid up to the Planck scale, that give a composite Higgs from a new fundamental strong force acting on fermions and scalars. Yukawa interactions of these particles with Standard Model fermions realize the partial compositeness scenario. Unde...

  20. Partially ordered models

    NARCIS (Netherlands)

    Fernandez, R.; Deveaux, V.

    2010-01-01

    We provide a formal definition and study the basic properties of partially ordered chains (POC). These systems were proposed to model textures in image processing and to represent independence relations between random variables in statistics (in the later case they are known as Bayesian networks).

  1. Partially Hidden Markov Models

    DEFF Research Database (Denmark)

    Forchhammer, Søren Otto; Rissanen, Jorma

    1996-01-01

    Partially Hidden Markov Models (PHMM) are introduced. They differ from the ordinary HMM's in that both the transition probabilities of the hidden states and the output probabilities are conditioned on past observations. As an illustration they are applied to black and white image compression where...

  2. Honesty in partial logic

    NARCIS (Netherlands)

    W. van der Hoek (Wiebe); J.O.M. Jaspars; E. Thijsse

    1995-01-01

    textabstractWe propose an epistemic logic in which knowledge is fully introspective and implies truth, although truth need not imply epistemic possibility. The logic is presented in sequential format and is interpreted in a natural class of partial models, called balloon models. We examine the

  3. Algebraic partial Boolean algebras

    International Nuclear Information System (INIS)

    Smith, Derek

    2003-01-01

    Partial Boolean algebras, first studied by Kochen and Specker in the 1960s, provide the structure for Bell-Kochen-Specker theorems which deny the existence of non-contextual hidden variable theories. In this paper, we study partial Boolean algebras which are 'algebraic' in the sense that their elements have coordinates in an algebraic number field. Several of these algebras have been discussed recently in a debate on the validity of Bell-Kochen-Specker theorems in the context of finite precision measurements. The main result of this paper is that every algebraic finitely-generated partial Boolean algebra B(T) is finite when the underlying space H is three-dimensional, answering a question of Kochen and showing that Conway and Kochen's infinite algebraic partial Boolean algebra has minimum dimension. This result contrasts the existence of an infinite (non-algebraic) B(T) generated by eight elements in an abstract orthomodular lattice of height 3. We then initiate a study of higher-dimensional algebraic partial Boolean algebras. First, we describe a restriction on the determinants of the elements of B(T) that are generated by a given set T. We then show that when the generating set T consists of the rays spanning the minimal vectors in a real irreducible root lattice, B(T) is infinite just if that root lattice has an A 5 sublattice. Finally, we characterize the rays of B(T) when T consists of the rays spanning the minimal vectors of the root lattice E 8

  4. EPU correction scheme study at the CLS

    Energy Technology Data Exchange (ETDEWEB)

    Bertwistle, Drew, E-mail: drew.bertwistle@lightsource.ca; Baribeau, C.; Dallin, L.; Chen, S.; Vogt, J.; Wurtz, W. [Canadian Light Source Inc. 44 Innovation Boulevard, Saskatoon, SK S7N 2V3 (Canada)

    2016-07-27

    The Canadian Light Source (CLS) Quantum Materials Spectroscopy Center (QMSC) beamline will employ a novel double period (55 mm, 180 mm) elliptically polarizing undulator (EPU) to produce photons of arbitrary polarization in the soft X-ray regime. The long period and high field of the 180 mm period EPU will have a strong dynamic focusing effect on the storage ring electron beam. We have considered two partial correction schemes, a 4 m long planar array of BESSY-II style current strips, and soft iron L-shims. In this paper we briefly consider the implementation of these correction schemes.

  5. Corrections to primordial nucleosynthesis

    International Nuclear Information System (INIS)

    Dicus, D.A.; Kolb, E.W.; Gleeson, A.M.; Sudarshan, E.C.G.; Teplitz, V.L.; Turner, M.S.

    1982-01-01

    The changes in primordial nucleosynthesis resulting from small corrections to rates for weak processes that connect neutrons and protons are discussed. The weak rates are corrected by improved treatment of Coulomb and radiative corrections, and by inclusion of plasma effects. The calculations lead to a systematic decrease in the predicted 4 He abundance of about ΔY = 0.0025. The relative changes in other primoridal abundances are also 1 to 2%

  6. Comparison of six methods of segmentation of tumor volume on the 18F-F.D.G. PET scan with reference histological volume in non small cell bronchopulmonary cancers

    International Nuclear Information System (INIS)

    Venel, Y.; Garhi, H.; Baulieu, J.L.; Prunier-Aesch, C.; Muret, A. de; Barillot, I.

    2008-01-01

    diameter. Today no method can correctly estimate the volume of smaller tumours. To improve those segmentation approaches, partial volume effect correction needs to be implemented for small tumours or tumours close to mediastinal local extension. The main indication of segmentation based on F.D.G. PET is tumour greater than 2 cm for which treatment will be radiotherapy alone or radiotherapy associated with chemotherapy. Our study is important because it compares the different methods described in the literature with the reference histological volume of the tumor, which is the only way to validate tumor segmentation method. (authors)

  7. Partially composite Higgs models

    DEFF Research Database (Denmark)

    Alanne, Tommi; Buarque Franzosi, Diogo; Frandsen, Mads T.

    2018-01-01

    We study the phenomenology of partially composite-Higgs models where electroweak symmetry breaking is dynamically induced, and the Higgs is a mixture of a composite and an elementary state. The models considered have explicit realizations in terms of gauge-Yukawa theories with new strongly...... interacting fermions coupled to elementary scalars and allow for a very SM-like Higgs state. We study constraints on their parameter spaces from vacuum stability and perturbativity as well as from LHC results and find that requiring vacuum stability up to the compositeness scale already imposes relevant...... constraints. A small part of parameter space around the classically conformal limit is stable up to the Planck scale. This is however already strongly disfavored by LHC results. in different limits, the models realize both (partially) composite-Higgs and (bosonic) technicolor models and a dynamical extension...

  8. Photogenic partial seizures.

    Science.gov (United States)

    Hennessy, M J; Binnie, C D

    2000-01-01

    To establish the incidence and symptoms of partial seizures in a cohort of patients investigated on account of known sensitivity to intermittent photic stimulation and/or precipitation of seizures by environmental visual stimuli such as television (TV) screens or computer monitors. We report 43 consecutive patients with epilepsy, who had exhibited a significant EEG photoparoxysmal response or who had seizures precipitated by environmental visual stimuli and underwent detailed assessment of their photosensitivity in the EEG laboratory, during which all were questioned concerning their ictal symptoms. All patients were considered on clinical grounds to have an idiopathic epilepsy syndrome. Twenty-eight (65%) patients reported visually precipitated attacks occurring initially with maintained consciousness, in some instances evolving to a period of confusion or to a secondarily generalized seizure. Visual symptoms were most commonly reported and included positive symptoms such as coloured circles or spots, but also blindness and subjective symptoms such as "eyes going funny." Other symptoms described included nonspecific cephalic sensations, deja-vu, auditory hallucinations, nausea, and vomiting. No patient reported any clear spontaneous partial seizures, and there were no grounds for supposing that any had partial epilepsy excepting the ictal phenomenology of some or all of the visually induced attacks. These findings provide clinical support for the physiological studies that indicate that the trigger mechanism for human photosensitivity involves binocularly innervated cells located in the visual cortex. Thus the visual cortex is the seat of the primary epileptogenic process, and the photically triggered discharges and seizures may be regarded as partial with secondary generalization.

  9. Arthroscopic partial medial meniscectomy

    Directory of Open Access Journals (Sweden)

    Dašić Žarko

    2011-01-01

    Full Text Available Background/Aim. Meniscal injuries are common in professional or recreational sports as well as in daily activities. If meniscal lesions lead to physical impairment they usually require surgical treatment. Arthroscopic treatment of meniscal injuries is one of the most often performed orthopedic operative procedures. Methods. The study analyzed the results of arthroscopic partial medial meniscectomy in 213 patients in a 24-month period, from 2006, to 2008. Results. In our series of arthroscopically treated medial meniscus tears we noted 78 (36.62% vertical complete bucket handle lesions, 19 (8.92% vertical incomplete lesions, 18 (8.45% longitudinal tears, 35 (16.43% oblique tears, 18 (8.45% complex degenerative lesions, 17 (7.98% radial lesions and 28 (13.14% horisontal lesions. Mean preoperative International Knee Documentation Committee (IKDC score was 49.81%, 1 month after the arthroscopic partial medial meniscectomy the mean IKDC score was 84.08%, and 6 months after mean IKDC score was 90.36%. Six months after the procedure 197 (92.49% of patients had good or excellent subjective postoperative clinical outcomes, while 14 (6.57% patients subjectively did not notice a significant improvement after the intervention, and 2 (0.93% patients had no subjective improvement after the partial medial meniscectomy at all. Conclusion. Arthroscopic partial medial meniscetomy is minimally invasive diagnostic and therapeutic procedure and in well selected cases is a method of choice for treatment of medial meniscus injuries when repair techniques are not a viable option. It has small rate of complications, low morbidity and fast rehabilitation.

  10. Lyapunov stability and thermal stability of partially relaxed fluids and plasmas

    International Nuclear Information System (INIS)

    Elsaesser, K.; Spiess, P.

    1996-01-01

    The relation between the Lyapunov stability of a Hamiltonian system and the thermal stability of a fluid whose temperature is controlled from outside is explored: The free energy as a functional of the correct variables (specific volume, local entropy, and some Clebsch potentials of the velocity) may serve as a Lyapunov functional, depending on the open-quote open-quote Casimirs close-quote close-quote as exchanged quantities. For a multi-species plasma one obtains a sufficient condition for stability: γ(v 2 /c 2 s )-1 s the sound speed. Some features of partially relaxed (T=const) cylindrical plasmas are also discussed. copyright 1996 American Institute of Physics

  11. Hierarchical partial order ranking

    International Nuclear Information System (INIS)

    Carlsen, Lars

    2008-01-01

    Assessing the potential impact on environmental and human health from the production and use of chemicals or from polluted sites involves a multi-criteria evaluation scheme. A priori several parameters are to address, e.g., production tonnage, specific release scenarios, geographical and site-specific factors in addition to various substance dependent parameters. Further socio-economic factors may be taken into consideration. The number of parameters to be included may well appear to be prohibitive for developing a sensible model. The study introduces hierarchical partial order ranking (HPOR) that remedies this problem. By HPOR the original parameters are initially grouped based on their mutual connection and a set of meta-descriptors is derived representing the ranking corresponding to the single groups of descriptors, respectively. A second partial order ranking is carried out based on the meta-descriptors, the final ranking being disclosed though average ranks. An illustrative example on the prioritisation of polluted sites is given. - Hierarchical partial order ranking of polluted sites has been developed for prioritization based on a large number of parameters

  12. Partial Differential Equations

    CERN Document Server

    1988-01-01

    The volume contains a selection of papers presented at the 7th Symposium on differential geometry and differential equations (DD7) held at the Nankai Institute of Mathematics, Tianjin, China, in 1986. Most of the contributions are original research papers on topics including elliptic equations, hyperbolic equations, evolution equations, non-linear equations from differential geometry and mechanics, micro-local analysis.

  13. Weekly bi-fractionated 40 Gy three-dimensional conformational accelerated partial irradiation of breast: results of a phase II French pilot study

    International Nuclear Information System (INIS)

    Bourgier, C.; Pichenot, C.; Verstraet, R.; Heymann, S.; Biron, B.; Delaloge, S.; Garbay, J.R.; Marsiglia, H.; Bourhis, J.; Taghian, A.; Marsiglia, H.

    2010-01-01

    The authors report the first French experience of three-dimensional conformational and accelerated partial irradiation of breast. Twenty five patients have been concerned by this phase II trial. The prescribed total dose was 40 Gy, was delivered over 5 days in two daily fractions. Irradiation was performed with two 6 MV tangential mini-beams and a 6-22 MeV front electron beams. The planning target volume coverage was very good. Toxicity has been assessed. Healthy tissues (heart, lungs) are considerably protected. The acute and late toxicity is correct. Short communication

  14. Publisher Correction: Predicting unpredictability

    Science.gov (United States)

    Davis, Steven J.

    2018-06-01

    In this News & Views article originally published, the wrong graph was used for panel b of Fig. 1, and the numbers on the y axes of panels a and c were incorrect; the original and corrected Fig. 1 is shown below. This has now been corrected in all versions of the News & Views.

  15. Multigrid and defect correction for the steady Navier-Stokes equations : application to aerodynamics

    NARCIS (Netherlands)

    Koren, B.

    1991-01-01

    Theoretical and expcrimental convergence results are presented for nonlinear multigrid and iterative defect correction applied to finite volume discretizations of the full, steady, 2D, compressible NavierStokes equations. lterative defect correction is introduced for circumventing the difficulty in

  16. Multigrid and defect correction for the steady Navier-Stokes equations

    NARCIS (Netherlands)

    Koren, B.

    1990-01-01

    Theoretical and experimental convergence results are presented for nonlinear multigrid and iterative defect correction applied to finite volume discretizations of the full, steady, 2D, compressible Navier-Stokes equations. Iterative defect correction is introduced for circumventing the difficulty in

  17. Local defect correction for boundary integral equation methods

    NARCIS (Netherlands)

    Kakuba, G.; Anthonissen, M.J.H.

    2014-01-01

    The aim in this paper is to develop a new local defect correction approach to gridding for problems with localised regions of high activity in the boundary element method. The technique of local defect correction has been studied for other methods as finite difference methods and finite volume

  18. Partial transpose of two disjoint blocks in XY spin chains

    International Nuclear Information System (INIS)

    Coser, Andrea; Tonni, Erik; Calabrese, Pasquale

    2015-01-01

    We consider the partial transpose of the spin reduced density matrix of two disjoint blocks in spin chains admitting a representation in terms of free fermions, such as XY chains. We exploit the solution of the model in terms of Majorana fermions and show that such partial transpose in the spin variables is a linear combination of four Gaussian fermionic operators. This representation allows to explicitly construct and evaluate the integer moments of the partial transpose. We numerically study critical XX and Ising chains and we show that the asymptotic results for large blocks agree with conformal field theory predictions if corrections to the scaling are properly taken into account. (paper)

  19. Partially ordered algebraic systems

    CERN Document Server

    Fuchs, Laszlo

    2011-01-01

    Originally published in an important series of books on pure and applied mathematics, this monograph by a distinguished mathematician explores a high-level area in algebra. It constitutes the first systematic summary of research concerning partially ordered groups, semigroups, rings, and fields. The self-contained treatment features numerous problems, complete proofs, a detailed bibliography, and indexes. It presumes some knowledge of abstract algebra, providing necessary background and references where appropriate. This inexpensive edition of a hard-to-find systematic survey will fill a gap i

  20. Infinite partial summations

    International Nuclear Information System (INIS)

    Sprung, D.W.L.

    1975-01-01

    This paper is a brief review of those aspects of the effective interaction problem that can be grouped under the heading of infinite partial summations of the perturbation series. After a brief mention of the classic examples of infinite summations, the author turns to the effective interaction problem for two extra core particles. Their direct interaction is summed to produce the G matrix, while their indirect interaction through the core is summed in a variety of ways under the heading of core polarization. (orig./WL) [de

  1. On universal partial words

    OpenAIRE

    Chen, Herman Z. Q.; Kitaev, Sergey; Mütze, Torsten; Sun, Brian Y.

    2016-01-01

    A universal word for a finite alphabet $A$ and some integer $n\\geq 1$ is a word over $A$ such that every word in $A^n$ appears exactly once as a subword (cyclically or linearly). It is well-known and easy to prove that universal words exist for any $A$ and $n$. In this work we initiate the systematic study of universal partial words. These are words that in addition to the letters from $A$ may contain an arbitrary number of occurrences of a special `joker' symbol $\\Diamond\

  2. Partial differential equations

    CERN Document Server

    Agranovich, M S

    2002-01-01

    Mark Vishik's Partial Differential Equations seminar held at Moscow State University was one of the world's leading seminars in PDEs for over 40 years. This book celebrates Vishik's eightieth birthday. It comprises new results and survey papers written by many renowned specialists who actively participated over the years in Vishik's seminars. Contributions include original developments and methods in PDEs and related fields, such as mathematical physics, tomography, and symplectic geometry. Papers discuss linear and nonlinear equations, particularly linear elliptic problems in angles and gener

  3. Partial differential equations

    CERN Document Server

    Levine, Harold

    1997-01-01

    The subject matter, partial differential equations (PDEs), has a long history (dating from the 18th century) and an active contemporary phase. An early phase (with a separate focus on taut string vibrations and heat flow through solid bodies) stimulated developments of great importance for mathematical analysis, such as a wider concept of functions and integration and the existence of trigonometric or Fourier series representations. The direct relevance of PDEs to all manner of mathematical, physical and technical problems continues. This book presents a reasonably broad introductory account of the subject, with due regard for analytical detail, applications and historical matters.

  4. Elliptic partial differential equations

    CERN Document Server

    Han, Qing

    2011-01-01

    Elliptic Partial Differential Equations by Qing Han and FangHua Lin is one of the best textbooks I know. It is the perfect introduction to PDE. In 150 pages or so it covers an amazing amount of wonderful and extraordinary useful material. I have used it as a textbook at both graduate and undergraduate levels which is possible since it only requires very little background material yet it covers an enormous amount of material. In my opinion it is a must read for all interested in analysis and geometry, and for all of my own PhD students it is indeed just that. I cannot say enough good things abo

  5. Improving the developability profile of pyrrolidine progesterone receptor partial agonists

    Energy Technology Data Exchange (ETDEWEB)

    Kallander, Lara S.; Washburn, David G.; Hoang, Tram H.; Frazee, James S.; Stoy, Patrick; Johnson, Latisha; Lu, Qing; Hammond, Marlys; Barton, Linda S.; Patterson, Jaclyn R.; Azzarano, Leonard M.; Nagilla, Rakesh; Madauss, Kevin P.; Williams, Shawn P.; Stewart, Eugene L.; Duraiswami, Chaya; Grygielko, Eugene T.; Xu, Xiaoping; Laping, Nicholas J.; Bray, Jeffrey D.; Thompson, Scott K. (GSKPA)

    2010-09-17

    The previously reported pyrrolidine class of progesterone receptor partial agonists demonstrated excellent potency but suffered from serious liabilities including hERG blockade and high volume of distribution in the rat. The basic pyrrolidine amine was intentionally converted to a sulfonamide, carbamate, or amide to address these liabilities. The evaluation of the degree of partial agonism for these non-basic pyrrolidine derivatives and demonstration of their efficacy in an in vivo model of endometriosis is disclosed herein.

  6. Unilateral removable partial dentures.

    Science.gov (United States)

    Goodall, W A; Greer, A C; Martin, N

    2017-01-27

    Removable partial dentures (RPDs) are widely used to replace missing teeth in order to restore both function and aesthetics for the partially dentate patient. Conventional RPD design is frequently bilateral and consists of a major connector that bridges both sides of the arch. Some patients cannot and will not tolerate such an extensive appliance. For these patients, bridgework may not be a predictable option and it is not always possible to provide implant-retained restorations. This article presents unilateral RPDs as a potential treatment modality for such patients and explores indications and contraindications for their use, including factors relating to patient history, clinical presentation and patient wishes. Through case examples, design, material and fabrication considerations will be discussed. While their use is not widespread, there are a number of patients who benefit from the provision of unilateral RPDs. They are a useful treatment to have in the clinician's armamentarium, but a highly-skilled dental team and a specific patient presentation is required in order for them to be a reasonable and predictable prosthetic option.

  7. Effect of Hall Current and Finite Larmor Radius Corrections on ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Astrophysics and Astronomy; Volume 37; Issue 3. Effect of Hall Current and Finite Larmor Radius Corrections on Thermal Instability of Radiative Plasma for Star Formation in Interstellar Medium (ISM). Sachin Kaothekar. Research Article Volume 37 Issue 3 September 2016 Article ID 23 ...

  8. Tutorial on Online Partial Evaluation

    Directory of Open Access Journals (Sweden)

    William R. Cook

    2011-09-01

    Full Text Available This paper is a short tutorial introduction to online partial evaluation. We show how to write a simple online partial evaluator for a simple, pure, first-order, functional programming language. In particular, we show that the partial evaluator can be derived as a variation on a compositionally defined interpreter. We demonstrate the use of the resulting partial evaluator for program optimization in the context of model-driven development.

  9. Correction of Neonatal Hypovolemia

    Directory of Open Access Journals (Sweden)

    V. V. Moskalev

    2007-01-01

    Full Text Available Objective: to evaluate the efficiency of hydroxyethyl starch solution (6% refortane, Berlin-Chemie versus fresh frozen plasma used to correct neonatal hypovolemia.Materials and methods. In 12 neonatal infants with hypoco-agulation, hypovolemia was corrected with fresh frozen plasma (10 ml/kg body weight. In 13 neonates, it was corrected with 6% refortane infusion in a dose of 10 ml/kg. Doppler echocardiography was used to study central hemodynamic parameters and Doppler study was employed to examine regional blood flow in the anterior cerebral and renal arteries.Results. Infusion of 6% refortane and fresh frozen plasma at a rate of 10 ml/hour during an hour was found to normalize the parameters of central hemodynamics and regional blood flow.Conclusion. Comparative analysis of the findings suggests that 6% refortane is the drug of choice in correcting neonatal hypovolemia. Fresh frozen plasma should be infused in hemostatic disorders. 

  10. Corrective Jaw Surgery

    Medline Plus

    Full Text Available ... surgery. It is important to understand that your treatment, which will probably include orthodontics before and after ... to realistically estimate the time required for your treatment. Correction of Common Dentofacial Deformities ​ ​ The information provided ...

  11. Corrective Jaw Surgery

    Medline Plus

    Full Text Available ... misalignment of jaws and teeth. Surgery can improve chewing, speaking and breathing. While the patient's appearance may ... indicate the need for corrective jaw surgery: Difficulty chewing, or biting food Difficulty swallowing Chronic jaw or ...

  12. Corrective Jaw Surgery

    Medline Plus

    Full Text Available ... It can also invite bacteria that lead to gum disease. Click here to find out more. Who We ... It can also invite bacteria that lead to gum disease. Click here to find out more. Corrective Jaw ...

  13. Corrective Jaw Surgery

    Medline Plus

    Full Text Available ... is performed by an oral and maxillofacial surgeon (OMS) to correct a wide range of minor and ... when sleeping, including snoring) Your dentist, orthodontist and OMS will work together to determine whether you are ...

  14. Hamiltonian partial differential equations and applications

    CERN Document Server

    Nicholls, David; Sulem, Catherine

    2015-01-01

    This book is a unique selection of work by world-class experts exploring the latest developments in Hamiltonian partial differential equations and their applications. Topics covered within are representative of the field’s wide scope, including KAM and normal form theories, perturbation and variational methods, integrable systems, stability of nonlinear solutions as well as applications to cosmology, fluid mechanics and water waves. The volume contains both surveys and original research papers and gives a concise overview of the above topics, with results ranging from mathematical modeling to rigorous analysis and numerical simulation. It will be of particular interest to graduate students as well as researchers in mathematics and physics, who wish to learn more about the powerful and elegant analytical techniques for Hamiltonian partial differential equations.

  15. Type-Directed Partial Evaluation

    DEFF Research Database (Denmark)

    Danvy, Olivier

    1998-01-01

    Type-directed partial evaluation uses a normalization function to achieve partial evaluation. These lecture notes review its background, foundations, practice, and applications. Of specific interest is the modular technique of offline and online type-directed partial evaluation in Standard ML...

  16. Type-Directed Partial Evaluation

    DEFF Research Database (Denmark)

    Danvy, Olivier

    1998-01-01

    Type-directed partial evaluation uses a normalization function to achieve partial evaluation. These lecture notes review its background, foundations, practice, and applications. Of specific interest is the modular technique of offline and online type-directed partial evaluation in Standard ML of ...

  17. Organ volume estimation using SPECT

    CERN Document Server

    Zaidi, H

    1996-01-01

    Knowledge of in vivo thyroid volume has both diagnostic and therapeutic importance and could lead to a more precise quantification of absolute activity contained in the thyroid gland. In order to improve single-photon emission computed tomography (SPECT) quantitation, attenuation correction was performed according to Chang's algorithm. The dual-window method was used for scatter subtraction. We used a Monte Carlo simulation of the SPECT system to accurately determine the scatter multiplier factor k. Volume estimation using SPECT was performed by summing up the volume elements (voxels) lying within the contour of the object, determined by a fixed threshold and the gray level histogram (GLH) method. Thyroid phantom and patient studies were performed and the influence of 1) fixed thresholding, 2) automatic thresholding, 3) attenuation, 4) scatter, and 5) reconstruction filter were investigated. This study shows that accurate volume estimation of the thyroid gland is feasible when accurate corrections are perform...

  18. ICT: isotope correction toolbox.

    Science.gov (United States)

    Jungreuthmayer, Christian; Neubauer, Stefan; Mairinger, Teresa; Zanghellini, Jürgen; Hann, Stephan

    2016-01-01

    Isotope tracer experiments are an invaluable technique to analyze and study the metabolism of biological systems. However, isotope labeling experiments are often affected by naturally abundant isotopes especially in cases where mass spectrometric methods make use of derivatization. The correction of these additive interferences--in particular for complex isotopic systems--is numerically challenging and still an emerging field of research. When positional information is generated via collision-induced dissociation, even more complex calculations for isotopic interference correction are necessary. So far, no freely available tools can handle tandem mass spectrometry data. We present isotope correction toolbox, a program that corrects tandem mass isotopomer data from tandem mass spectrometry experiments. Isotope correction toolbox is written in the multi-platform programming language Perl and, therefore, can be used on all commonly available computer platforms. Source code and documentation can be freely obtained under the Artistic License or the GNU General Public License from: https://github.com/jungreuc/isotope_correction_toolbox/ {christian.jungreuthmayer@boku.ac.at,juergen.zanghellini@boku.ac.at} Supplementary data are available at Bioinformatics online. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  19. Applied partial differential equations

    CERN Document Server

    Logan, J David

    2004-01-01

    This primer on elementary partial differential equations presents the standard material usually covered in a one-semester, undergraduate course on boundary value problems and PDEs. What makes this book unique is that it is a brief treatment, yet it covers all the major ideas: the wave equation, the diffusion equation, the Laplace equation, and the advection equation on bounded and unbounded domains. Methods include eigenfunction expansions, integral transforms, and characteristics. Mathematical ideas are motivated from physical problems, and the exposition is presented in a concise style accessible to science and engineering students; emphasis is on motivation, concepts, methods, and interpretation, rather than formal theory. This second edition contains new and additional exercises, and it includes a new chapter on the applications of PDEs to biology: age structured models, pattern formation; epidemic wave fronts, and advection-diffusion processes. The student who reads through this book and solves many of t...

  20. Inductance loop and partial

    CERN Document Server

    Paul, Clayton R

    2010-01-01

    "Inductance is an unprecedented text, thoroughly discussing "loop" inductance as well as the increasingly important "partial" inductance. These concepts and their proper calculation are crucial in designing modern high-speed digital systems. World-renowned leader in electromagnetics Clayton Paul provides the knowledge and tools necessary to understand and calculate inductance." "With the present and increasing emphasis on high-speed digital systems and high-frequency analog systems, it is imperative that system designers develop an intimate understanding of the concepts and methods in this book. Inductance is a much-needed textbook designed for senior and graduate-level engineering students, as well as a hands-on guide for working engineers and professionals engaged in the design of high-speed digital and high-frequency analog systems."--Jacket.

  1. Partial oxidation process

    International Nuclear Information System (INIS)

    Najjar, M.S.

    1987-01-01

    A process is described for the production of gaseous mixtures comprising H/sub 2/+CO by the partial oxidation of a fuel feedstock comprising a heavy liquid hydrocarbonaceous fuel having a nickel, iron, and vanadium-containing ash or petroleum coke having a nickel, iron, and vanadium-containing ash, or mixtures thereof. The feedstock includes a minimum of 0.5 wt. % of sulfur and the ash includes a minimum of 5.0 wt. % vanadium, a minimum of 0.5 ppm nickel, and a minimum of 0.5 ppm iron. The process comprises: (1) mixing together a copper-containing additive with the fuel feedstock; wherein the weight ratio of copper-containing additive to ash in the fuel feedstock is in the range of about 1.0-10.0, and there is at least 10 parts by weight of copper for each part by weight of vanadium; (2) reacting the mixture from (1) at a temperature in the range of 2200 0 F to 2900 0 F and a pressure in the range of about 5 to 250 atmospheres in a free-flow refactory lined partial oxidation reaction zone with a free-oxygen containing gas in the presence of a temperature moderator and in a reducing atmosphere to produce a hot raw effluent gas stream comprising H/sub 2/+CO and entrained molten slag; and where in the reaction zone and the copper-containing additive combines with at least a portion of the nickel and iron constituents and sulfur found in the feedstock to produce a liquid phase washing agent that collects and transports at least a portion of the vanadium-containing oxide laths and spinels and other ash components and refractory out of the reaction zone; and (3) separating nongaseous materials from the hot raw effluent gas stream

  2. Clinically significant change in stroke volume in pulmonary hypertension

    NARCIS (Netherlands)

    van Wolferen, S.A.; van de Veerdonk, M.C.; Mauritz, G.J.; Jacobs, W.; Marcus, J.T.; Marques, K.M.J.; Bronzwaer, J.G.F.; Heijmans, M.W.; Boonstra, A.; Postmus, P.E.; Westerhof, N.; Noordegraaf, A.V.

    2011-01-01

    Background: Stroke volume is probably the best hemodynamic parameter because it reflects therapeutic changes and contains prognostic information in pulmonary hypertension (PH). Stroke volume directly reflects right ventricular function in response to its load, without the correction of compensatory

  3. Partial status epilepticus - rapid genetic diagnosis of Alpers' disease.

    LENUS (Irish Health Repository)

    McCoy, Bláthnaid

    2011-11-01

    We describe four children with a devastating encephalopathy characterised by refractory focal seizures and variable liver dysfunction. We describe their electroencephalographic, radiologic, genetic and pathologic findings. The correct diagnosis was established by rapid gene sequencing. POLG1 based Alpers\\' disease should be considered in any child presenting with partial status epilepticus.

  4. Nonlinear partial differential equations and their applications

    CERN Document Server

    Lions, Jacques Louis

    2002-01-01

    This book contains the written versions of lectures delivered since 1997 in the well-known weekly seminar on Applied Mathematics at the Collège de France in Paris, directed by Jacques-Louis Lions. It is the 14th and last of the series, due to the recent and untimely death of Professor Lions. The texts in this volume deal mostly with various aspects of the theory of nonlinear partial differential equations. They present both theoretical and applied results in many fields of growing importance such as Calculus of variations and optimal control, optimization, system theory and control, op

  5. Numerical Methods for Partial Differential Equations

    CERN Document Server

    Guo, Ben-yu

    1987-01-01

    These Proceedings of the first Chinese Conference on Numerical Methods for Partial Differential Equations covers topics such as difference methods, finite element methods, spectral methods, splitting methods, parallel algorithm etc., their theoretical foundation and applications to engineering. Numerical methods both for boundary value problems of elliptic equations and for initial-boundary value problems of evolution equations, such as hyperbolic systems and parabolic equations, are involved. The 16 papers of this volume present recent or new unpublished results and provide a good overview of current research being done in this field in China.

  6. Simulation-based artifact correction (SBAC) for metrological computed tomography

    Science.gov (United States)

    Maier, Joscha; Leinweber, Carsten; Sawall, Stefan; Stoschus, Henning; Ballach, Frederic; Müller, Tobias; Hammer, Michael; Christoph, Ralf; Kachelrieß, Marc

    2017-06-01

    Computed tomography (CT) is a valuable tool for the metrolocical assessment of industrial components. However, the application of CT to the investigation of highly attenuating objects or multi-material components is often restricted by the presence of CT artifacts caused by beam hardening, x-ray scatter, off-focal radiation, partial volume effects or the cone-beam reconstruction itself. In order to overcome this limitation, this paper proposes an approach to calculate a correction term that compensates for the contribution of artifacts and thus enables an appropriate assessment of these components using CT. Therefore, we make use of computer simulations of the CT measurement process. Based on an appropriate model of the object, e.g. an initial reconstruction or a CAD model, two simulations are carried out. One simulation considers all physical effects that cause artifacts using dedicated analytic methods as well as Monte Carlo-based models. The other one represents an ideal CT measurement i.e. a measurement in parallel beam geometry with a monochromatic, point-like x-ray source and no x-ray scattering. Thus, the difference between these simulations is an estimate for the present artifacts and can be used to correct the acquired projection data or the corresponding CT reconstruction, respectively. The performance of the proposed approach is evaluated using simulated as well as measured data of single and multi-material components. Our approach yields CT reconstructions that are nearly free of artifacts and thereby clearly outperforms commonly used artifact reduction algorithms in terms of image quality. A comparison against tactile reference measurements demonstrates the ability of the proposed approach to increase the accuracy of the metrological assessment significantly.

  7. Geological Corrections in Gravimetry

    Science.gov (United States)

    Mikuška, J.; Marušiak, I.

    2015-12-01

    Applying corrections for the known geology to gravity data can be traced back into the first quarter of the 20th century. Later on, mostly in areas with sedimentary cover, at local and regional scales, the correction known as gravity stripping has been in use since the mid 1960s, provided that there was enough geological information. Stripping at regional to global scales became possible after releasing the CRUST 2.0 and later CRUST 1.0 models in the years 2000 and 2013, respectively. Especially the later model provides quite a new view on the relevant geometries and on the topographic and crustal densities as well as on the crust/mantle density contrast. Thus, the isostatic corrections, which have been often used in the past, can now be replaced by procedures working with an independent information interpreted primarily from seismic studies. We have developed software for performing geological corrections in space domain, based on a-priori geometry and density grids which can be of either rectangular or spherical/ellipsoidal types with cells of the shapes of rectangles, tesseroids or triangles. It enables us to calculate the required gravitational effects not only in the form of surface maps or profiles but, for instance, also along vertical lines, which can shed some additional light on the nature of the geological correction. The software can work at a variety of scales and considers the input information to an optional distance from the calculation point up to the antipodes. Our main objective is to treat geological correction as an alternative to accounting for the topography with varying densities since the bottoms of the topographic masses, namely the geoid or ellipsoid, generally do not represent geological boundaries. As well we would like to call attention to the possible distortions of the corrected gravity anomalies. This work was supported by the Slovak Research and Development Agency under the contract APVV-0827-12.

  8. Methods for the correction of vascular artifacts in PET O-15 water brain-mapping studies

    Science.gov (United States)

    Chen, Kewei; Reiman, E. M.; Lawson, M.; Yun, Lang-sheng; Bandy, D.; Palant, A.

    1996-12-01

    While positron emission tomographic (PET) measurements of regional cerebral blood flow (rCBF) can be used to map brain regions that are involved in normal and pathological human behaviors, measurements in the anteromedial temporal lobe can be confounded by the combined effects of radiotracer activity in neighboring arteries and partial-volume averaging. The authors now describe two simple methods to address this vascular artifact. One method utilizes the early frames of a dynamic PET study, while the other method utilizes a coregistered magnetic resonance image (MRI) to characterize the vascular region of interest (VROI). Both methods subsequently assign a common value to each pixel in the VROI for the control (baseline) scan and the activation scan. To study the vascular artifact and to demonstrate the ability of the proposed methods correcting the vascular artifact, four dynamic PET scans were performed in a single subject during the same behavioral state. For each of the four scans, a vascular scan containing vascular activity was computed as the summation of the images acquired 0-60 s after radiotracer administration, and a control scan containing minimal vascular activity was computed as the summation of the images acquired 20-80 s after radiotracer administration. t-score maps calculated from the four pairs of vascular and control scans were used to characterize regional blood flow differences related to vascular activity before and after the application of each vascular artifact correction method. Both methods eliminated the observed differences in vascular activity, as well as the vascular artifact observed in the anteromedial temporal lobes. Using PET data from a study of normal human emotion, these methods permitted the authors to identify rCBF increases in the anteromedial temporal lobe free from the potentially confounding, combined effects of vascular activity and partial-volume averaging.

  9. Methods for the correction of vascular artifacts in PET O-15 water brain-mapping studies

    International Nuclear Information System (INIS)

    Chen, K.; Reiman, E.M.; Good Samaritan Regional Medical Center, Phoenix, AZ; Lawson, M.; Yun, L.S.; Bandy, D.

    1996-01-01

    While positron emission tomographic (PET) measurements of regional cerebral blood flow (rCBF) can be used to map brain regions that are involved in normal and pathological human behaviors, measurements in the anteromedial temporal lobe can be confounded by the combined effects of radiotracer activity in neighboring arteries and partial-volume averaging. The authors now describe two simple methods to address this vascular artifact. One method utilizes the early frames of a dynamic PET study, while the other method utilizes a coregistered magnetic resonance image (MRI) to characterize the vascular region of interest (VROI). Both methods subsequently assign a common value to each pixel in the VROI for the control scan and the activation scan. To study the vascular artifact and to demonstrate the ability of the proposed methods correcting the vascular artifact, four dynamic PET scans were performed in a single subject during the same behavioral state. For each of the four scans, a vascular scan containing vascular activity was computed as the summation of the images acquired 0--60 s after radiotracer administrations, and a control scan containing minimal vascular activity was computed as the summation of the images acquired 20--80 s after radiotracer administration. t-score maps calculated from the four pairs of vascular and control scans were used to characterize regional blood flow differences related to vascular activity before and after the applications of each vascular artifact correction method. Both methods eliminated the observed differences in vascular activity, as well as the vascular artifact observed in the anteromedial temporal lobes. Using PET data from a study of normal human emotion, these methods permitted us to identify rCBF increases in the anteromedial temporal lobe free from the potentially confounding, combined effects of vascular activity and partial-volume averaging

  10. PET/CT detectability and classification of simulated pulmonary lesions using an SUV correction scheme

    Science.gov (United States)

    Morrow, Andrew N.; Matthews, Kenneth L., II; Bujenovic, Steven

    2008-03-01

    Positron emission tomography (PET) and computed tomography (CT) together are a powerful diagnostic tool, but imperfect image quality allows false positive and false negative diagnoses to be made by any observer despite experience and training. This work investigates PET acquisition mode, reconstruction method and a standard uptake value (SUV) correction scheme on the classification of lesions as benign or malignant in PET/CT images, in an anthropomorphic phantom. The scheme accounts for partial volume effect (PVE) and PET resolution. The observer draws a region of interest (ROI) around the lesion using the CT dataset. A simulated homogenous PET lesion of the same shape as the drawn ROI is blurred with the point spread function (PSF) of the PET scanner to estimate the PVE, providing a scaling factor to produce a corrected SUV. Computer simulations showed that the accuracy of the corrected PET values depends on variations in the CT-drawn boundary and the position of the lesion with respect to the PET image matrix, especially for smaller lesions. Correction accuracy was affected slightly by mismatch of the simulation PSF and the actual scanner PSF. The receiver operating characteristic (ROC) study resulted in several observations. Using observer drawn ROIs, scaled tumor-background ratios (TBRs) more accurately represented actual TBRs than unscaled TBRs. For the PET images, 3D OSEM outperformed 2D OSEM, 3D OSEM outperformed 3D FBP, and 2D OSEM outperformed 2D FBP. The correction scheme significantly increased sensitivity and slightly increased accuracy for all acquisition and reconstruction modes at the cost of a small decrease in specificity.

  11. Dancoff Correction in Square and Hexagonal Lattices

    Energy Technology Data Exchange (ETDEWEB)

    Carlvik, I

    1966-11-15

    This report presents the results of a series of calculations of Dancoff corrections for square and hexagonal rod lattices. The tables cover a wide range of volume ratios and moderator cross sections. The results were utilized for checking the approximative formula of Sauer and also the modification of Bonalumi to Sauer's formula. The modified formula calculates the Dancoff correction with an accuracy of 0.01 - 0.02 in cases of practical interest. Calculations have also been performed on square lattices with an empty gap surrounding the rods. The results demonstrate the error involved in treating this kind of geometry by means of homogenizing the gap and the moderator. The calculations were made on the Ferranti Mercury computer of AB Atomenergi before it was closed down. Since then FORTRAN routines for Dancoff corrections have been written, and a subroutine DASQHE is included in the report.

  12. Anatomically Correct Surface Recovery

    DEFF Research Database (Denmark)

    Jensen, Rasmus Ramsbøl; Nielsen, Jannik Boll; Larsen, Rasmus

    2015-01-01

    using the learned statistics. A quantitative evaluation is performed on a data set of 10 laser scans of ear canal impressions with minimal noise and artificial holes. We also present a qualitative evaluation on authentic partial scans from an actual direct in ear scanner prototype. Compared to a state...

  13. Experts' understanding of partial derivatives using the Partial Derivative Machine

    OpenAIRE

    Roundy, David; Dorko, Allison; Dray, Tevian; Manogue, Corinne A.; Weber, Eric

    2014-01-01

    Partial derivatives are used in a variety of different ways within physics. Most notably, thermodynamics uses partial derivatives in ways that students often find confusing. As part of a collaboration with mathematics faculty, we are at the beginning of a study of the teaching of partial derivatives, a goal of better aligning the teaching of multivariable calculus with the needs of students in STEM disciplines. As a part of this project, we have performed a pilot study of expert understanding...

  14. Robust Active Label Correction

    DEFF Research Database (Denmark)

    Kremer, Jan; Sha, Fei; Igel, Christian

    2018-01-01

    for the noisy data lead to different active label correction algorithms. If loss functions consider the label noise rates, these rates are estimated during learning, where importance weighting compensates for the sampling bias. We show empirically that viewing the true label as a latent variable and computing......Active label correction addresses the problem of learning from input data for which noisy labels are available (e.g., from imprecise measurements or crowd-sourcing) and each true label can be obtained at a significant cost (e.g., through additional measurements or human experts). To minimize......). To select labels for correction, we adopt the active learning strategy of maximizing the expected model change. We consider the change in regularized empirical risk functionals that use different pointwise loss functions for patterns with noisy and true labels, respectively. Different loss functions...

  15. Generalised Batho correction factor

    International Nuclear Information System (INIS)

    Siddon, R.L.

    1984-01-01

    There are various approximate algorithms available to calculate the radiation dose in the presence of a heterogeneous medium. The Webb and Fox product over layers formulation of the generalised Batho correction factor requires determination of the number of layers and the layer densities for each ray path. It has been shown that the Webb and Fox expression is inefficient for the heterogeneous medium which is expressed as regions of inhomogeneity rather than layers. The inefficiency of the layer formulation is identified as the repeated problem of determining for each ray path which inhomogeneity region corresponds to a particular layer. It has been shown that the formulation of the Batho correction factor as a product over inhomogeneity regions avoids that topological problem entirely. The formulation in terms of a product over regions simplifies the computer code and reduces the time required to calculate the Batho correction factor for the general heterogeneous medium. (U.K.)

  16. THE SECONDARY EXTINCTION CORRECTION

    Energy Technology Data Exchange (ETDEWEB)

    Zachariasen, W. H.

    1963-03-15

    It is shown that Darwin's formula for the secondary extinction correction, which has been universally accepted and extensively used, contains an appreciable error in the x-ray diffraction case. The correct formula is derived. As a first order correction for secondary extinction, Darwin showed that one should use an effective absorption coefficient mu + gQ where an unpolarized incident beam is presumed. The new derivation shows that the effective absorption coefficient is mu + 2gQ(1 + cos/sup 4/2 theta )/(1 plus or minus cos/sup 2/2 theta )/s up 2/, which gives mu + gQ at theta =0 deg and theta = 90 deg , but mu + 2gQ at theta = 45 deg . Darwin's theory remains valid when applied to neutron diffraction. (auth)

  17. NLO corrections to the pair production of supersymmetric particles

    International Nuclear Information System (INIS)

    Obikhod, T.V.; Verbytskyy, A.A.

    2014-01-01

    The analysis of recent experimental data received from LHC (CMS) restricts the range of MSSM parameters. Using computer programs SOFTSUSY, SDECAY the mass spectrum and partial width of superpartners are calculated. With the help of computer program PROSPINO the calculations of the next-to-leading order (NLO) corrections to the production cross sections of superpartners are made. With the help of computer program PYTHIA the NLO corrections on differential distributions of p T and η for squarks and gluino are represented.

  18. Bryant J. correction formula

    International Nuclear Information System (INIS)

    Tejera R, A.; Cortes P, A.; Becerril V, A.

    1990-03-01

    For the practical application of the method proposed by J. Bryant, the authors carried out a series of small corrections, related with the bottom, the dead time of the detectors and channels, with the resolution time of the coincidences, with the accidental coincidences, with the decay scheme and with the gamma efficiency of the beta detector beta and the beta efficiency beta of the gamma detector. The calculation of the correction formula is presented in the development of the present report, being presented 25 combinations of the probability of the first existent state at once of one disintegration and the second state at once of the following disintegration. (Author)

  19. Model Correction Factor Method

    DEFF Research Database (Denmark)

    Christensen, Claus; Randrup-Thomsen, Søren; Morsing Johannesen, Johannes

    1997-01-01

    The model correction factor method is proposed as an alternative to traditional polynomial based response surface techniques in structural reliability considering a computationally time consuming limit state procedure as a 'black box'. The class of polynomial functions is replaced by a limit...... of the model correction factor method, is that in simpler form not using gradient information on the original limit state function or only using this information once, a drastic reduction of the number of limit state evaluation is obtained together with good approximations on the reliability. Methods...

  20. Partial Actions and Power Sets

    Directory of Open Access Journals (Sweden)

    Jesús Ávila

    2013-01-01

    Full Text Available We consider a partial action (X,α with enveloping action (T,β. In this work we extend α to a partial action on the ring (P(X,Δ,∩ and find its enveloping action (E,β. Finally, we introduce the concept of partial action of finite type to investigate the relationship between (E,β and (P(T,β.

  1. Algorithms over partially ordered sets

    DEFF Research Database (Denmark)

    Baer, Robert M.; Østerby, Ole

    1969-01-01

    in partially ordered sets, answer the combinatorial question of how many maximal chains might exist in a partially ordered set withn elements, and we give an algorithm for enumerating all maximal chains. We give (in § 3) algorithms which decide whether a partially ordered set is a (lower or upper) semi......-lattice, and whether a lattice has distributive, modular, and Boolean properties. Finally (in § 4) we give Algol realizations of the various algorithms....

  2. Attenuation correction for SPECT

    International Nuclear Information System (INIS)

    Hosoba, Minoru

    1986-01-01

    Attenuation correction is required for the reconstruction of a quantitative SPECT image. A new method for detecting body contours, which are important for the correction of tissue attenuation, is presented. The effect of body contours, detected by the newly developed method, on the reconstructed images was evaluated using various techniques for attenuation correction. The count rates in the specified region of interest in the phantom image by the Radial Post Correction (RPC) method, the Weighted Back Projection (WBP) method, Chang's method were strongly affected by the accuracy of the contours, as compared to those by Sorenson's method. To evaluate the effect of non-uniform attenuators on the cardiac SPECT, computer simulation experiments were performed using two types of models, the uniform attenuator model (UAM) and the non-uniform attenuator model (NUAM). The RPC method showed the lowest relative percent error (%ERROR) in UAM (11 %). However, 20 to 30 percent increase in %ERROR was observed for NUAM reconstructed with the RPC, WBP, and Chang's methods. Introducing an average attenuation coefficient (0.12/cm for Tc-99m and 0.14/cm for Tl-201) in the RPC method decreased %ERROR to the levels for UAM. Finally, a comparison between images, which were obtained by 180 deg and 360 deg scans and reconstructed from the RPC method, showed that the degree of the distortion of the contour of the simulated ventricles in the 180 deg scan was 15 % higher than that in the 360 deg scan. (Namekawa, K.)

  3. Text Induced Spelling Correction

    NARCIS (Netherlands)

    Reynaert, M.W.C.

    2004-01-01

    We present TISC, a language-independent and context-sensitive spelling checking and correction system designed to facilitate the automatic removal of non-word spelling errors in large corpora. Its lexicon is derived from a very large corpus of raw text, without supervision, and contains word

  4. Correctness of concurrent processes

    NARCIS (Netherlands)

    E.R. Olderog (Ernst-Rüdiger)

    1989-01-01

    textabstractA new notion of correctness for concurrent processes is introduced and investigated. It is a relationship P sat S between process terms P built up from operators of CCS [Mi 80], CSP [Ho 85] and COSY [LTS 79] and logical formulas S specifying sets of finite communication sequences as in

  5. Error Correcting Codes -34 ...

    Indian Academy of Sciences (India)

    information and coding theory. A large scale relay computer had failed to deliver the expected results due to a hardware fault. Hamming, one of the active proponents of computer usage, was determined to find an efficient means by which computers could detect and correct their own faults. A mathematician by train-.

  6. Measured attenuation correction methods

    International Nuclear Information System (INIS)

    Ostertag, H.; Kuebler, W.K.; Doll, J.; Lorenz, W.J.

    1989-01-01

    Accurate attenuation correction is a prerequisite for the determination of exact local radioactivity concentrations in positron emission tomography. Attenuation correction factors range from 4-5 in brain studies to 50-100 in whole body measurements. This report gives an overview of the different methods of determining the attenuation correction factors by transmission measurements using an external positron emitting source. The long-lived generator nuclide 68 Ge/ 68 Ga is commonly used for this purpose. The additional patient dose from the transmission source is usually a small fraction of the dose due to the subsequent emission measurement. Ring-shaped transmission sources as well as rotating point or line sources are employed in modern positron tomographs. By masking a rotating line or point source, random and scattered events in the transmission scans can be effectively suppressed. The problems of measured attenuation correction are discussed: Transmission/emission mismatch, random and scattered event contamination, counting statistics, transmission/emission scatter compensation, transmission scan after administration of activity to the patient. By using a double masking technique simultaneous emission and transmission scans become feasible. (orig.)

  7. Corrective Jaw Surgery

    Medline Plus

    Full Text Available ... their surgery, orthognathic surgery is performed to correct functional problems. Jaw Surgery can have a dramatic effect on many aspects of life. Following are some of the conditions that may ... front, or side Facial injury Birth defects Receding lower jaw and ...

  8. Error Correcting Codes

    Indian Academy of Sciences (India)

    successful consumer products of all time - the Compact Disc. (CD) digital audio .... We can make ... only 2 t additional parity check symbols are required, to be able to correct t .... display information (contah'ling music related data and a table.

  9. Error Correcting Codes

    Indian Academy of Sciences (India)

    Science and Automation at ... the Reed-Solomon code contained 223 bytes of data, (a byte ... then you have a data storage system with error correction, that ..... practical codes, storing such a table is infeasible, as it is generally too large.

  10. Partial order infinitary term rewriting

    DEFF Research Database (Denmark)

    Bahr, Patrick

    2014-01-01

    We study an alternative model of infinitary term rewriting. Instead of a metric on terms, a partial order on partial terms is employed to formalise convergence of reductions. We consider both a weak and a strong notion of convergence and show that the metric model of convergence coincides with th...... to the metric setting -- orthogonal systems are both infinitarily confluent and infinitarily normalising in the partial order setting. The unique infinitary normal forms that the partial order model admits are Böhm trees....

  11. JMBR VOLUME 15 Number 2 Decemebr 2016 - correction.cdr

    African Journals Online (AJOL)

    Fine Print

    Mallory-Weiss tears, acute stress gastritis, Dieulafoy lesion, non-steroidal anti- inflammatory drugs ... age (> 60 years), in both males and females2. ... anxious, pale, dehydrated, afebrile, anicteric ... frank blood were evacuated on digital.

  12. JMBR VOLUME 15 Number 2 Decemebr 2016 - correction.cdr

    African Journals Online (AJOL)

    Fine Print

    patient satisfaction in a selected tertiary health facility, in Benin City, Nigeria. The research ... consumer of health care services in the. 1, 2 medical ... satisfaction is associated with several behavioral ..... Themes and Perspective. London.

  13. JMBR VOLUME 15 Number 1 JUNE 2016 - correction.cdr

    African Journals Online (AJOL)

    Fineprint

    2016-06-01

    Jun 1, 2016 ... to the unbooked. Low social class of unbooked women influenced their not ... Antenatal Care (ANC) is a continued risk. 1 assessment of ... identifying and treating the earliest signs ..... Orhue A.A, Ande A.B.A, Maternal Mortality.

  14. JMBR VOLUME 15 Number 1 JUNE 2016 - correction.cdr

    African Journals Online (AJOL)

    Fineprint

    2016-06-01

    Jun 1, 2016 ... ABSTRACT. Acute appendicitis is the most common surgical abdominal emergency worldwide. The initial diagnosis is mainly clinical and the treatment of choice is appendicectomy. A Negative appendicectomy is the absence of inflammation or pathology in the appendix. To determine the negative ...

  15. JMBR VOLUME 15 Number 2 Decemebr 2016 - correction.cdr

    African Journals Online (AJOL)

    Fine Print

    Great Prof. Osime did his undergraduate medical training in the Asias and his postgraduate training in the United Kingdom. After a stint at Ahmadu Bello. University, Zaria, he joined the University of Benin and the University of Benin. Teaching Hospital (UBTH) as Lecturer I and Honorary Consultant respectively in. 1972.

  16. JMBR VOLUME 15 Number 1 JUNE 2016 - correction.cdr

    African Journals Online (AJOL)

    Fineprint

    2016-06-01

    Jun 1, 2016 ... to overpopulation in some medical schools. Some authors in the past have looked at the relationship between admission grades and performance of medical students at the Professional. 5,10,11,12. MBBS degree examination as well as predictive validity of preclinical students' performance in the MBBS ...

  17. JMBR VOLUME 15 Number 1 JUNE 2016 - correction.cdr

    African Journals Online (AJOL)

    Fineprint

    2016-06-01

    Jun 1, 2016 ... ... to cement dust are strongly linked to an increased risk of ... among the cement factory workers with. 20.0% of the workers .... groups of respondents was also assessed .... exposed persons compared with controls. 10,17.

  18. JMBR VOLUME 15 Number 1 JUNE 2016 - correction.cdr

    African Journals Online (AJOL)

    Fineprint

    2016-06-01

    Jun 1, 2016 ... JMBR: A Peer-review Journal of Biomedical Sciences. June 2016, Vol. 15 No. ... Combination therapy, Plasmodium falciparum. Introduction. Multidrug .... JMBR 2016:15(1). 76....Journal of Medicine and Biomedical Research ...

  19. JMBR VOLUME 15 Number 2 Decemebr 2016 - correction.cdr

    African Journals Online (AJOL)

    Fine Print

    This study investigated the influence of nurses' communication of nursing care on patient satisfaction in a selected tertiary ... communication skills will be helpful in interactions between nurses and the patients during the period of admission. ... communication is an important part of the patient ability to understand and act.

  20. JMBR VOLUME 15 Number 1 JUNE 2016 - correction.cdr

    African Journals Online (AJOL)

    Fineprint

    2016-06-01

    Jun 1, 2016 ... based on the seven diagnostic criteria by the National institute of Health and the diagnosis made when there ... plain radiographs and Computed tomography play major roles in the diagnosis of. NF-1. .... defect in the occipital bone as well as thinning of the right ... pigmented cutaneous lesions, multiple soft.

  1. JMBR VOLUME 15 Number 2 Decemebr 2016 - correction.cdr

    African Journals Online (AJOL)

    Fine Print

    weekday and a weekend food diary to document the types of food, fruits, snacks and ... Results: A total of 509 patients were studied (M:F ratio of 1:2.2), an age ... these recommendations displayed a trend towards poor blood pressure control.

  2. JMBR VOLUME 15 Number 2 Decemebr 2016 - correction.cdr

    African Journals Online (AJOL)

    Fine Print

    include trading and farming. There are rivers located within ... These urine samples were transported to the University of Benin. Teaching Hospital, UBTH, in Benin City for further procession. Each urine sample was observed for any visible evidence of ... A total of 200 urine samples from Primary and junior secondary school ...

  3. JMBR VOLUME 15 Number 1 JUNE 2016 - correction.cdr

    African Journals Online (AJOL)

    Fineprint

    2016-06-01

    Jun 1, 2016 ... administered questionnaire and the respondents' genotypes were determined by the use of an ... practice of premarital genotype screening included; age, being married, parental ..... expectations of the study was explained to.

  4. JMBR VOLUME 15 Number 2 Decemebr 2016 - correction.cdr

    African Journals Online (AJOL)

    Fine Print

    across the country; stock-outs of antiretroviral medications in several health facilities and irregular supply of. 7 rapid HIV test kits, etc. Without specific intervention, the relatively high prevalence of HIV infection in Benin City increases risk of. MTCT of HIV infection, in Benin City. This creates an urgent need to review,.

  5. JMBR VOLUME 15 Number 2 Decemebr 2016 - correction.cdr

    African Journals Online (AJOL)

    Fine Print

    contains modest amount of salt and zinc tablets, use of anti-infective agents and. 3 non- antimicrobial anti diarrhea agents . It has also been documented that ... spreading crown, it can grow up to 30 m tall, popularly known as the African locust bean, called Ogiri amongst the. Ibos, Dawadawa (Hausa) and Iru (Yoruba).

  6. JMBR VOLUME 15 Number 2 Decemebr 2016 - correction.cdr

    African Journals Online (AJOL)

    Fine Print

    ABSTRACT. Urinary schistosomiasis is endemic in Nigeria and continues to pose public ... tract infections, urethral and ureteral stricture with ... infection between groups of children, sex and age ... very low positive predictive value because of ...

  7. JMBR VOLUME 15 Number 1 JUNE 2016 - correction.cdr

    African Journals Online (AJOL)

    Fineprint

    2016-06-01

    Jun 1, 2016 ... stem bark of Terminalia macroptera is safe for consumption in rats but caution must be given to ... evidence of the side effects associated with these medicinal plants .... obtain serum with an electric centrifuge- ..... mild inflammatory cells detected in the liver slides .... spectrophotometric method for measuring.

  8. JMBR VOLUME 15 Number 1 JUNE 2016 - correction.cdr

    African Journals Online (AJOL)

    Fineprint

    2016-06-01

    Jun 1, 2016 ... Majority felt that the advantages of dental implants were ... disadvantages of dental implants (table 6). 68.7% of the ... Nigerian media about dental implants. ... social sciences.2003. ... Representative marketing - oriented study.

  9. JMBR VOLUME 15 Number 1 JUNE 2016 - correction.cdr

    African Journals Online (AJOL)

    Fineprint

    2016-06-01

    Jun 1, 2016 ... pregnant women at delivery and their relationship with birth weight of babies. Blood cadmium, plasma zinc ... especially sea foods, cereals, roots and leaves of .... The protein helps to ... blood, urine, saliva and hair samples by.

  10. JMBR VOLUME 15 Number 2 Decemebr 2016 - correction.cdr

    African Journals Online (AJOL)

    Fine Print

    prevalence of HCV infection and potential risk factors among students in a tertiary educational institution. .... students involved in cigarette smoking was positive for .... and Felix, E. (2008). Prevalence of antibody to hepatitis C virus in apparently healthy Port Harcourt blood donors and association with blood groups and other.

  11. JMBR VOLUME 15 Number 1 JUNE 2016 - correction.cdr

    African Journals Online (AJOL)

    Fineprint

    2016-06-01

    Jun 1, 2016 ... adolescents in selected secondary schools around the University of Ibadan. The ... menstrual protective materials used by the respondents. ... MDG 3 (promotes gender equality and ..... However, this study has provided.

  12. Intersection based motion correction of multislice MRI for 3-D in utero fetal brain image formation.

    Science.gov (United States)

    Kim, Kio; Habas, Piotr A; Rousseau, Francois; Glenn, Orit A; Barkovich, Anthony J; Studholme, Colin

    2010-01-01

    In recent years, postprocessing of fast multislice magnetic resonance imaging (MRI) to correct fetal motion has provided the first true 3-D MR images of the developing human brain in utero. Early approaches have used reconstruction based algorithms, employing a two-step iterative process, where slices from the acquired data are realigned to an approximate 3-D reconstruction of the fetal brain, which is then refined further using the improved slice alignment. This two step slice-to-volume process, although powerful, is computationally expensive in needing a 3-D reconstruction, and is limited in its ability to recover subvoxel alignment. Here, we describe an alternative approach which we term slice intersection motion correction (SIMC), that seeks to directly co-align multiple slice stacks by considering the matching structure along all intersecting slice pairs in all orthogonally planned slices that are acquired in clinical imaging studies. A collective update scheme for all slices is then derived, to simultaneously drive slices into a consistent match along their lines of intersection. We then describe a 3-D reconstruction algorithm that, using the final motion corrected slice locations, suppresses through-plane partial volume effects to provide a single high isotropic resolution 3-D image. The method is tested on simulated data with known motions and is applied to retrospectively reconstruct 3-D images from a range of clinically acquired imaging studies. The quantitative evaluation of the registration accuracy for the simulated data sets demonstrated a significant improvement over previous approaches. An initial application of the technique to studying clinical pathology is included, where the proposed method recovered up to 15 mm of translation and 30 degrees of rotation for individual slices, and produced full 3-D reconstructions containing clinically useful additional information not visible in the original 2-D slices.

  13. On the electrodynamics of partial discharges in voids in solid dielectrics

    DEFF Research Database (Denmark)

    Pedersen, Aage

    1989-01-01

    It is suggested that a correct interpretation of partial-discharge transients can be obtained only through the concept of induced charge. The application of this concept enables a partial-discharge theory to be developed by means of which the influence of relevant void parameters can be assessed ...

  14. Publisher Correction to

    NARCIS (Netherlands)

    Barrio, Isabel C.; Lindén, Elin; Beest, Te Mariska; Olofsson, Johan; Rocha, Adrian; Soininen, Eeva M.; Alatalo, Juha M.; Andersson, Tommi; Asmus, Ashley; Boike, Julia; Bråthen, Kari Anne; Bryant, John P.; Buchwal, Agata; Bueno, C.G.; Christie, Katherine S.; Egelkraut, Dagmar; Ehrich, Dorothee; Fishback, Lee Ann; Forbes, Bruce C.; Gartzia, Maite; Grogan, Paul; Hallinger, Martin; Heijmans, Monique M.P.D.; Hik, David S.; Hofgaard, Annika; Holmgren, Milena; Høye, Toke T.; Huebner, Diane C.; Jónsdóttir, Ingibjörg Svala; Kaarlejärvi, Elina; Kumpula, Timo; Lange, Cynthia Y.M.J.G.; Lange, Jelena; Lévesque, Esther; Limpens, Juul; Macias-Fauria, Marc; Myers-Smith, Isla; Nieukerken, van Erik J.; Normand, Signe; Post, Eric S.; Schmidt, Niels Martin; Sitters, Judith; Skoracka, Anna; Sokolov, Alexander; Sokolova, Natalya; Speed, James D.M.; Street, Lorna E.; Sundqvist, Maja K.; Suominen, Otso; Tananaev, Nikita; Tremblay, Jean Pierre; Urbanowicz, Christine; Uvarov, Sergey A.; Watts, David; Wilmking, Martin; Wookey, Philip A.; Zimmermann, Heike H.; Zverev, Vitali; Kozlov, Mikhail V.

    2018-01-01

    The above mentioned article was originally scheduled for publication in the special issue on Ecology of Tundra Arthropods with guest editors Toke T. Høye . Lauren E. Culler. Erroneously, the article was published in Polar Biology, Volume 40, Issue 11, November, 2017. The publisher sincerely

  15. On Degenerate Partial Differential Equations

    OpenAIRE

    Chen, Gui-Qiang G.

    2010-01-01

    Some of recent developments, including recent results, ideas, techniques, and approaches, in the study of degenerate partial differential equations are surveyed and analyzed. Several examples of nonlinear degenerate, even mixed, partial differential equations, are presented, which arise naturally in some longstanding, fundamental problems in fluid mechanics and differential geometry. The solution to these fundamental problems greatly requires a deep understanding of nonlinear degenerate parti...

  16. [Acrylic resin removable partial dentures

    NARCIS (Netherlands)

    Baat, C. de; Witter, D.J.; Creugers, N.H.J.

    2011-01-01

    An acrylic resin removable partial denture is distinguished from other types of removable partial dentures by an all-acrylic resin base which is, in principle, solely supported by the edentulous regions of the tooth arch and in the maxilla also by the hard palate. When compared to the other types of

  17. Partial Epilepsy with Auditory Features

    Directory of Open Access Journals (Sweden)

    J Gordon Millichap

    2004-07-01

    Full Text Available The clinical characteristics of 53 sporadic (S cases of idiopathic partial epilepsy with auditory features (IPEAF were analyzed and compared to previously reported familial (F cases of autosomal dominant partial epilepsy with auditory features (ADPEAF in a study at the University of Bologna, Italy.

  18. Turbulent piloted partially-premixed flames with varying levels of O2/N2: stability limits and PDF calculations

    Science.gov (United States)

    Juddoo, Mrinal; Masri, Assaad R.; Pope, Stephen B.

    2011-12-01

    This paper reports measured stability limits and PDF calculations of piloted, turbulent flames of compressed natural gas (CNG) partially-premixed with either pure oxygen, or with varying levels of O2/N2. Stability limits are presented for flames of CNG fuel premixed with up to 20% oxygen as well as CNG-O2-N2 fuel where the O2 content is varied from 8 to 22% by volume. Calculations are presented for (i) Sydney flame B [Masri et al. 1988] which uses pure CNG as well as flames B15 to B25 where the CNG is partially-premixed with 15-25% oxygen by volume, respectively and (ii) Sandia methane-air (1:3 by volume) flame E [Barlow et al. 2005] as well as new flames E15 and E25 that are partially-premixed with 'reconstituted air' where the O2 content in nitrogen is 15 and 25% by volume, respectively. The calculations solve a transported PDF of composition using a particle-based Monte Carlo method and employ the EMST mixing model as well as detailed chemical kinetics. The addition of oxygen to the fuel increases stability, shortens the flames, broadens the reaction zone, and shifts the stoichiometric mixture fraction towards the inner side of the jet. It is found that for pure CNG flames where the reaction zone is narrow (∼0.1 in mixture fraction space), the PDF calculations fail to reproduce the correct level of local extinction on approach to blow-off. A broadening in the reaction zone up to about 0.25 in mixture fraction space is needed for the PDF/EMST approach to be able to capture these finite-rate chemistry effects. It is also found that for the same level of partial premixing, increasing the O2/N2 ratio increases the maximum levels of CO and NO but shifts the peak to richer mixture fractions. Over the range of oxygenation investigated here, stability limits have shown to improve almost linearly with increasing oxygen levels in the fuel and with increasing the contribution of release rate from the pilot.

  19. Correction of refractive errors

    Directory of Open Access Journals (Sweden)

    Vladimir Pfeifer

    2005-10-01

    Full Text Available Background: Spectacles and contact lenses are the most frequently used, the safest and the cheapest way to correct refractive errors. The development of keratorefractive surgery has brought new opportunities for correction of refractive errors in patients who have the need to be less dependent of spectacles or contact lenses. Until recently, RK was the most commonly performed refractive procedure for nearsighted patients.Conclusions: The introduction of excimer laser in refractive surgery has given the new opportunities of remodelling the cornea. The laser energy can be delivered on the stromal surface like in PRK or deeper on the corneal stroma by means of lamellar surgery. In LASIK flap is created with microkeratome in LASEK with ethanol and in epi-LASIK the ultra thin flap is created mechanically.

  20. PS Booster Orbit Correction

    CERN Document Server

    Chanel, M; Rumolo, G; Tomás, R; CERN. Geneva. AB Department

    2008-01-01

    At the end of the 2007 run, orbit measurements were carried out in the 4 rings of the PS Booster (PSB) for different working points and beam energies. The aim of these measurements was to provide the necessary input data for a PSB realignment campaign during the 2007/2008 shutdown. Currently, only very few corrector magnets can be operated reliably in the PSB; therefore the orbit correction has to be achieved by displacing (horizontally and vertically) and/or tilting some of the defocusing quadrupoles (QDs). In this report we first describe the orbit measurements, followed by a detailed explanation of the orbit correction strategy. Results and conclusions are presented in the last section.