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Sample records for computed tomography-a preliminary

  1. Preliminary Experimental Results on Controlled Cardiac Computed Tomography: A Phantom Study

    PubMed Central

    Lu, Yang; Cai, Zhijun; Wang, Ge; Zhao, Jun; Bai, Er-Wei

    2010-01-01

    In this paper, we present the preliminary experimental results on controlled cardiac computed tomography (CT), which aims to reduce the motion artifacts by means of controlling the x-ray source rotation speed. An innovative cardiac phantom enables us to perform this experiment without modifying the scanner. It is the first experiment on the cardiac CT with speed controlled x-ray source. Experimental results demonstrate that the proposed method successfully separates the phantom images at different phases (improve the temporal resolution) though controlling the x-ray speed. PMID:19696470

  2. Age estimation by pulp-to-tooth area ratio using cone-beam computed tomography: A preliminary analysis

    PubMed Central

    Rai, Arpita; Acharya, Ashith B.; Naikmasur, Venkatesh G.

    2016-01-01

    Background: Age estimation of living or deceased individuals is an important aspect of forensic sciences. Conventionally, pulp-to-tooth area ratio (PTR) measured from periapical radiographs have been utilized as a nondestructive method of age estimation. Cone-beam computed tomography (CBCT) is a new method to acquire three-dimensional images of the teeth in living individuals. Aims: The present study investigated age estimation based on PTR of the maxillary canines measured in three planes obtained from CBCT image data. Settings and Design: Sixty subjects aged 20–85 years were included in the study. Materials and Methods: For each tooth, mid-sagittal, mid-coronal, and three axial sections—cementoenamel junction (CEJ), one-fourth root level from CEJ, and mid-root—were assessed. PTR was calculated using AutoCAD software after outlining the pulp and tooth. Statistical Analysis Used: All statistical analyses were performed using an SPSS 17.0 software program. Results and Conclusions: Linear regression analysis showed that only PTR in axial plane at CEJ had significant age correlation (r = 0.32; P < 0.05). This is probably because of clearer demarcation of pulp and tooth outline at this level. PMID:28123269

  3. Computed tomography: A versatile technology

    SciTech Connect

    Armistead, R.A.; Stanley, J.H.

    1997-02-01

    Improvements in the speed and accuracy of computed tomography (CT) systems, together with new developments in software, are changing the ways CT technology supports manufacturing operations. In addition to providing quantitative nondestructive inspection at the end of the manufacturing line, CT images are now also being compiled for reverse engineering and first-article characterization and certification. The enhanced performance of a state-of-the-art CT system makes it an effective complement to other digital data-based manufacturing technologies such as computer-aided design (CAD), computer-aided manufacturing (CAM), and computer-aided engineering (CAE). Furthermore, CT capabilities may be combined with those of rapid prototyping such as stereolithography, selective laser sintering, and direct metal deposition, to support the rapid, cost-efficient production of parts in small lots. This article describes how the system works, how it is used for inspection, and how it may assist with reverse engineering.

  4. 99mTc-IgG-Lung Scintigraphy in the Assessment of Pulmonary Involvement in Interstitial Lung Disease and Its Comparison With Pulmonary Function Tests and High-Resolution Computed Tomography: A Preliminary Study

    PubMed Central

    Bahtouee, Mehrzad; Saberifard, Jamshid; Javadi, Hamid; Nabipour, Iraj; Malakizadeh, Hasan; Monavvarsadegh, Gholamhossein; Ilkhani Pak, Hoda; Sadeghi, Azadeh; Assadi, Majid

    2015-01-01

    Background: The discrimination of inactive inflammatory processes from the active form of the disease is of great importance in the management of interstitial lung disease (ILD). Objectives: The aim of this study was to determine the efficacy of 99mTc-IgG scan for the detection of severity of disease compared to high-resolution computed tomography (HRCT) and pulmonary function test (PFT). Patients and Methods: Eight known cases of ILD including four cases of Mustard gas (MG) intoxication and four patients with ILD of unknown cause were included in this study. A population of six patients without lung disease was considered as the control group. The patients underwent PFT and high-resolution computed tomography, followed by 99mTc-IgG scan. They were followed up for one year. 99mTc-IgG scan assessment of IgG uptake was accomplished both qualitatively (subjectively) and semiquantitatively. Results: All eight ILD patients demonstrated a strong increase in 99mTc-IgG uptake in the lungs, compared to the control patients. The 99mTc-IgG scan scores were higher in the patient group (0.64[95% confidence interval(CI)=0.61-0.69])) than the control group (0.35 (0.35[95% CI=0.28-0.40]), (P<0.05)). In patients, a statistically significant positive correlation was detected between 99mTc-IgG scan and HRCT scores (Spearman’s correlation coefficient = 0.92, P < 0.008). The 99mTc-Human Immunoglobulin (HIG) scores were not significantly correlated with PFT findings (including FVC, FEV1, FEV1/FVC), O2 saturation and age ( P values > 0.05). There were no significant correlations between 99mTc-IgG score and HRCT patterns including ground glass opacity, reticular fibrosis and honeycombing (P value > 0.05). Conclusion: The present results confirmed that 99mTc-IgG scan could be applied to detect the severity of pulmonary involvement, which was well correlated with HRCT findings. This data also showed that the 99mTc-IgG scan might be used as a complement to HRCT in the functional evaluation

  5. 99mTc-MIBI Lung Scintigraphy in the Assessment of Pulmonary Involvement in Interstitial Lung Disease and Its Comparison With Pulmonary Function Tests and High-Resolution Computed Tomography: A Preliminary Study.

    PubMed

    Bahtouee, Mehrzad; Saberifard, Jamshid; Javadi, Hamid; Nabipour, Iraj; Raeisi, Alireza; Assadi, Majid; Eftekhari, Mohammad

    2015-11-01

    The differentiation of active inflammatory processes from an inactive form of the disease is of great value in the management of interstitial lung disease (ILD). The aim of this investigation was to assess the efficacy of 99mTc-methoxy-isobutyl-isonitrile (99mTc-MIBI) scans in distinguishing the severity of the disease compared to radiological and clinical parameters.In total, 19 known cases of ILD were included in this study and were followed up for 1 year. Five patients without lung disease were considered as the control group. The patients underwent pulmonary function tests (PFTs) and high-resolution computed tomography scans, followed by 99mTc-MIBI scanning. The 99mTc-MIBI scans were analyzed either qualitatively (subjectively) or semiquantitatively.All 19 ILD patients demonstrated a strong increase in 99mTc-MIBI uptake in the lungs compared to the control group. The 99mTc-MIBI scan scores were higher in the patient group in both the early phase (0.24[0.19-0.31] vs 0.11[0.10-0.15], P < 0.05) and the delayed phase (0.15[0.09-0.27] vs 0.04[0.01-0.09], P < 0.05) compared with the control group. A positive correlation was detected between the 99mTc-MIBI scan and the high-resolution computed tomography (HRCT) scores (Spearman's correlation coefficient = 0.65, P < 0.02) in the early phase but not in the delayed phase in patients (P > 0.14). The 99mTc-MIBI scan scores were not significantly correlated with the PFT findings (P > 0.05). In total, 5 patients died and 14 patients were still alive over the 1-year follow-up period. There was also a significant difference between the uptake intensity of 99mTc-MIBI and the outcome in the early phase (dead: 0.32[0.29-0.43] vs alive: 0.21[0.18-0.24], P < 0.05) and delayed phase (dead: 0.27[0.22-0.28] vs alive: 0.10[0.07-0.19], P < 0.05).The washout rate was ~40 min starting from 20 min up to 60 min and this rate was significantly different in our 2 study groups (ILD: 46.61[15.61-50.39] vs NL: 70.91[27.09-116.36], P = 0.04).The

  6. Assessing stapes piston position using computed tomography: a cadaveric study.

    PubMed

    Hahn, Yoav; Diaz, Rodney; Hartman, Jonathan; Bobinski, Matthew; Brodie, Hilary

    2009-02-01

    Temporal bone computed tomographic (CT) scanning in the postoperative stapedotomy patient is inaccurate in assessing stapes piston position within the vestibule. Poststapedotomy patients that have persistent vertigo may undergo CT scanning to assess the position of the stapes piston within the vestibule to rule out overly deep insertion. Vertigo is a recognized complication of the deep piston, and CT evaluation is often recommended. The accuracy of CT scan in this setting is unestablished. Stapedotomy was performed on 12 cadaver ears, and stainless steel McGee pistons were placed. The cadaver heads were then scanned using a fine-cut temporal bone protocol. Temporal bone dissection was performed with microscopic measurement of the piston depth in the vestibule. These values were compared with depth of intravestibular penetration measured on CT scan by 4 independent measurements. The intravestibular penetration as assessed by computed tomography was consistently greater than the value found on cadaveric anatomic dissection. The radiographic bias was greater when piston location within the vestibule was shallower. The axial CT scan measurement was 0.53 mm greater, on average, than the anatomic measurement. On average, the coronal CT measurement was 0.68 mm greater than the anatomic measurement. The degree of overestimation of penetration, however, was highly inconsistent. Standard temporal bone CT scan is neither an accurate nor precise examination of stapes piston depth within the vestibule. We found that CT measurement consistently overstated intravestibular piston depth. Computed tomography is not a useful study in the evaluation of piston depth for poststapedectomy vertigo and is of limited value in this setting.

  7. X-ray luminescence computed tomography: a sensitivity study

    NASA Astrophysics Data System (ADS)

    Lun, Michael C.; Zhang, Wei; Li, Changqing

    2017-03-01

    X-ray luminescence computed tomography (XLCT) is a hybrid molecular imaging modality that uses high energy x-ray photons to excite nanophosphors (e.g. Europium doped Gadolinium Oxysulfide - GOS: Eu3+) emitting optical photons to be measured by a sensitive detector for image reconstruction. XLCT has potentials to combine both the merits of x-ray imaging (high spatial resolution) and optical imaging (high sensitivity), which makes XLCT an attractive imaging modality to image nanophosphor targets deeply embedded in turbid media. In this study, we have evaluated the sensitivity of XLCT with phantom experiments by scanning targets of different phosphor concentrations at different depths. Cylindrical phantoms embedded with a cylindrical target with varying concentrations of GOS: Eu3+ (27.6 mM, 2.76 mM, 276 μM, and 27.6 μM) were scanned inside our lab made XLCT imaging system for varying scanning depths (6, 11, 16, and 21 mm). We found that XLCT is capable of imaging targets of very low concentrations (27.6 μM or 0.01 mg/mL) at significant depths, such as 21 mm. Our results demonstrate that there is also little variation in the reconstructed target size for different imaging depths for XLCT. We have for the first time, compared the sensitivity of XLCT with that of traditional computed tomography (CT) for phosphor targets. We found that XLCT's use of x-ray induced photons provides much higher measurement sensitivity and contrast compared to CT which provides image contrast solely based on x-ray attenuation.

  8. Nanoparticle Contrast Agents for Computed Tomography: A Focus on Micelles

    PubMed Central

    Cormode, David P.; Naha, Pratap C.; Fayad, Zahi A.

    2014-01-01

    Computed tomography (CT) is an X-ray based whole body imaging technique that is widely used in medicine. Clinically approved contrast agents for CT are iodinated small molecules or barium suspensions. Over the past seven years there has been a great increase in the development of nanoparticles as CT contrast agents. Nanoparticles have several advantages over small molecule CT contrast agents, such as long blood-pool residence times, and the potential for cell tracking and targeted imaging applications. Furthermore, there is a need for novel CT contrast agents, due to the growing population of renally impaired patients and patients hypersensitive to iodinated contrast. Micelles and lipoproteins, a micelle-related class of nanoparticle, have notably been adapted as CT contrast agents. In this review we discuss the principles of CT image formation and the generation of CT contrast. We discuss the progress in developing non-targeted, targeted and cell tracking nanoparticle CT contrast agents. We feature agents based on micelles and used in conjunction with spectral CT. The large contrast agent doses needed will necessitate careful toxicology studies prior to clinical translation. However, the field has seen tremendous advances in the past decade and we expect many more advances to come in the next decade. PMID:24470293

  9. Acute Kidney Injury After Computed Tomography: A Meta-analysis.

    PubMed

    Aycock, Ryan D; Westafer, Lauren M; Boxen, Jennifer L; Majlesi, Nima; Schoenfeld, Elizabeth M; Bannuru, Raveendhara R

    2017-08-12

    Computed tomography (CT) is an important imaging modality used in the diagnosis of a variety of disorders. Imaging quality may be improved if intravenous contrast is added, but there is a concern for potential renal injury. Our goal is to perform a meta-analysis to compare the risk of acute kidney injury, need for renal replacement, and total mortality after contrast-enhanced CT versus noncontrast CT. We searched MEDLINE (PubMed), the Cochrane Library, CINAHL, Web of Science, ProQuest, and Academic Search Premier for relevant articles. Included articles specifically compared rates of renal insufficiency, need for renal replacement therapy, or mortality in patients who received intravenous contrast versus those who received no contrast. The database search returned 14,691 articles, inclusive of duplicates. Twenty-six unique articles met our inclusion criteria, with an additional 2 articles found through hand searching. In total, 28 studies involving 107,335 participants were included in the final analysis, all of which were observational. Meta-analysis demonstrated that, compared with noncontrast CT, contrast-enhanced CT was not significantly associated with either acute kidney injury (odds ratio [OR] 0.94; 95% confidence interval [CI] 0.83 to 1.07), need for renal replacement therapy (OR 0.83; 95% CI 0.59 to 1.16), or all-cause mortality (OR 1.0; 95% CI 0.73 to 1.36). We found no significant differences in our principal study outcomes between patients receiving contrast-enhanced CT versus those receiving noncontrast CT. Given similar frequencies of acute kidney injury in patients receiving noncontrast CT, other patient- and illness-level factors, rather than the use of contrast material, likely contribute to the development of acute kidney injury. Copyright © 2017 American College of Emergency Physicians. Published by Elsevier Inc. All rights reserved.

  10. Neutron stimulated emission computed tomography: a Monte Carlo simulation approach.

    PubMed

    Sharma, A C; Harrawood, B P; Bender, J E; Tourassi, G D; Kapadia, A J

    2007-10-21

    A Monte Carlo simulation has been developed for neutron stimulated emission computed tomography (NSECT) using the GEANT4 toolkit. NSECT is a new approach to biomedical imaging that allows spectral analysis of the elements present within the sample. In NSECT, a beam of high-energy neutrons interrogates a sample and the nuclei in the sample are stimulated to an excited state by inelastic scattering of the neutrons. The characteristic gammas emitted by the excited nuclei are captured in a spectrometer to form multi-energy spectra. Currently, a tomographic image is formed using a collimated neutron beam to define the line integral paths for the tomographic projections. These projection data are reconstructed to form a representation of the distribution of individual elements in the sample. To facilitate the development of this technique, a Monte Carlo simulation model has been constructed from the GEANT4 toolkit. This simulation includes modeling of the neutron beam source and collimation, the samples, the neutron interactions within the samples, the emission of characteristic gammas, and the detection of these gammas in a Germanium crystal. In addition, the model allows the absorbed radiation dose to be calculated for internal components of the sample. NSECT presents challenges not typically addressed in Monte Carlo modeling of high-energy physics applications. In order to address issues critical to the clinical development of NSECT, this paper will describe the GEANT4 simulation environment and three separate simulations performed to accomplish three specific aims. First, comparison of a simulation to a tomographic experiment will verify the accuracy of both the gamma energy spectra produced and the positioning of the beam relative to the sample. Second, parametric analysis of simulations performed with different user-defined variables will determine the best way to effectively model low energy neutrons in tissue, which is a concern with the high hydrogen content in

  11. Dose spread functions in computed tomography: A Monte Carlo study

    SciTech Connect

    Boone, John M.

    2009-10-15

    Purpose: Current CT dosimetry employing CTDI methodology has come under fire in recent years, partially in response to the increasing width of collimated x-ray fields in modern CT scanners. This study was conducted to provide a better understanding of the radiation dose distributions in CT. Methods: Monte Carlo simulations were used to evaluate radiation dose distributions along the z axis arising from CT imaging in cylindrical phantoms. Mathematical cylinders were simulated with compositions of water, polymethyl methacrylate (PMMA), and polyethylene. Cylinder diameters from 10 to 50 cm were studied. X-ray spectra typical of several CT manufacturers (80, 100, 120, and 140 kVp) were used. In addition to no bow tie filter, the head and body bow tie filters from modern General Electric and Siemens CT scanners were evaluated. Each cylinder was divided into three concentric regions of equal volume such that the energy deposited is proportional to dose for each region. Two additional dose assessment regions, central and edge locations 10 mm in diameter, were included for comparisons to CTDI{sub 100} measurements. Dose spread functions (DSFs) were computed for a wide number of imaging parameters. Results: DSFs generally exhibit a biexponential falloff from the z=0 position. For a very narrow primary beam input (<<1 mm), DSFs demonstrated significant low amplitude long range scatter dose tails. For body imaging conditions (30 cm diameter in water), the DSF at the center showed {approx}160 mm at full width at tenth maximum (FWTM), while at the edge the FWTM was {approx}80 mm. Polyethylene phantoms exhibited wider DSFs than PMMA or water, as did higher tube voltages in any material. The FWTM were 80, 180, and 250 mm for 10, 30, and 50 cm phantom diameters, respectively, at the center in water at 120 kVp with a typical body bow tie filter. Scatter to primary dose ratios (SPRs) increased with phantom diameter from 4 at the center (1 cm diameter) for a 16 cm diameter cylinder

  12. Column flotation monitoring based on electrical capacitance volume tomography: A preliminary study

    NASA Astrophysics Data System (ADS)

    Haryono, Didied; Harjanto, Sri; Nugraha, Harisma; Huda, Mahfudz Al; Taruno, Warsito Purwo

    2017-01-01

    A preliminary study of column flotation monitoring process using electrical capacitance volume tomography (ECVT) was conducted. ECVT was one of the monitoring systems which based on the capacitance measurement. It was used to understand the phenomenon that occurs inside the column in a three-dimensional (3-D) image. A linear back projection (LBP) algorithm technique was used to reconstruct the 3-D ECVT images from all measurement data obtained in this study. As a preliminary study, the effect of gas injection in the two-phase (liquid and gas) system was conducted. This study is conducted to assess the possibility of ECVT system in the monitoring of column flotation process. The experiments were conducted by using column flotation with 5 cm diameter and 150 cm height in which a sparger was installed at the bottom of column to inject air inside the column. 32-CH rectangular ECVT sensor was installed at 13 cm above the sparger and placed around the column. The gas injection variations used were 2-7 l/min with interval 1 l/min and all experiments were conducted at room temperature. Based on the signal and image analysis, the signals and 3-D ECVT images showed differences when the gas injection was varied. An increase in gas injection will decrease the fluctuation of signal intensity which correlates to the 3-D ECVT images. Average signals obtained by ECVT when given gas injection variations were in the range of 440.09 to 453.62 mV from high to low gas injection. Based on these results, ECVT has a prospect as an imaging tool to monitor the column flotation process. And also, hopefully, based on the analysis of 3-D images generated by ECVT system, the metallurgical performance would be analyzed in the further researches.

  13. Standardized medical terminology for cardiac computed tomography: a report of the Society of Cardiovascular Computed Tomography.

    PubMed

    Weigold, Wm Guy; Abbara, Suhny; Achenbach, Stephan; Arbab-Zadeh, Armin; Berman, Daniel; Carr, J Jeffrey; Cury, Ricardo C; Halliburton, Sandra S; McCollough, Cynthia H; Taylor, Allen J

    2011-01-01

    Since the emergence of cardiac computed tomography (CT) at the turn of the 21st century, there has been an exponential growth in research and clinical development of the technique, with contributions from investigators and clinicians from varied backgrounds: physics and engineering, informatics, cardiology, and radiology. However, terminology for the field is not unified. As a consequence, there are multiple abbreviations for some terms, multiple terms for some concepts, and some concepts that lack clear definitions and/or usage. In an effort to aid the work of all those who seek to contribute to the literature, clinical practice, and investigation of the field, the Society of Cardiovascular Computed Tomography sets forth a standard set of medical terms commonly used in clinical and investigative practice of cardiac CT.

  14. Upper crustal structure beneath East Java from ambient noise tomography: A preliminary result

    SciTech Connect

    Martha, Agustya Adi; Widiyantoro, Sri; Cummins, Phil; Saygin, Erdinc; Masturyono

    2015-04-24

    East Java has a fairly complex geological structure. Physiographically East Java can be divided into three zones, i.e. the Southern Mountains zone in the southern part, the Kendeng zone in the middle part, and the Rembang zone in the northern part. Most of the seismic hazards in this region are due to processes in the upper crust. In this study, the Ambient Noise Tomography (ANT) method is used to image the upper crustal structure beneath East Java. We have used seismic waveform data recorded by 8Meteorological, Climatological and Geophysical Agency (BMKG) stationary seismographic stations and 16 portable seismographs installed for 2 to 8 weeks. The data were processed to obtain waveforms fromnoise cross-correlation between pairs of seismographic stations. Our preliminary results indicate that the Kendeng zone, an area of low gravity anomaly, is associated with a low velocity zone. On the other hand, the southern mountain range, which has a high gravity anomaly, is related to a high velocity anomaly as shown by our tomographic images.

  15. Upper crustal structure beneath East Java from ambient noise tomography: A preliminary result

    NASA Astrophysics Data System (ADS)

    Martha, Agustya Adi; Widiyantoro, Sri; Cummins, Phil; Saygin, Erdinc; Masturyono

    2015-04-01

    East Java has a fairly complex geological structure. Physiographically East Java can be divided into three zones, i.e. the Southern Mountains zone in the southern part, the Kendeng zone in the middle part, and the Rembang zone in the northern part. Most of the seismic hazards in this region are due to processes in the upper crust. In this study, the Ambient Noise Tomography (ANT) method is used to image the upper crustal structure beneath East Java. We have used seismic waveform data recorded by 8Meteorological, Climatological and Geophysical Agency (BMKG) stationary seismographic stations and 16 portable seismographs installed for 2 to 8 weeks. The data were processed to obtain waveforms fromnoise cross-correlation between pairs of seismographic stations. Our preliminary results indicate that the Kendeng zone, an area of low gravity anomaly, is associated with a low velocity zone. On the other hand, the southern mountain range, which has a high gravity anomaly, is related to a high velocity anomaly as shown by our tomographic images.

  16. Coronary artery imaging with multidetector computed tomography: a call for an evidence-based, multidisciplinary approach.

    PubMed

    Schoenhagen, Paul; Stillman, Arthur E; Garcia, Mario J; Halliburton, Sandra S; Tuzcu, E Murat; Nissen, Steven E; Modic, Michael T; Lytle, Bruce W; Topol, Eric J; White, Richard D

    2006-05-01

    Modern multidetector computed tomography systems are capable of a comprehensive assessment of the cardiovascular system, including noninvasive assessment of coronary anatomy. Multidetector computed tomography is expected to advance the role of noninvasive imaging for coronary artery disease, but clinical experience is still limited. Clinical guidelines are necessary to standardize scanner technology and appropriate clinical applications for coronary computed tomographic angiography. Further evaluation of this evolving technology will benefit from cooperation between different medical specialties, imaging scientists, and manufacturers of multidetector computed tomography systems, supporting multidisciplinary teams focused on the diagnosis and treatment of early and advanced stages of coronary artery disease. This cooperation will provide the necessary education, training, and guidelines for physicians and technologists assuring standard of care for their patients.

  17. Recognition of a rare intrathoracic rib with computed tomography: a case report.

    PubMed

    Abdollahifar, Mohammad-Amin; Abdi, Shabnam; Bayat, Mohammad; Masteri Farahani, Reza; Abbaszadeh, Hojjat-Allah

    2017-03-01

    One of the uncommon congenital variations is intrathoracic rib which a normal, a bifid, or an accessory rib lies within the thoracic cavity that is founded accidentally. Clinically, in most cases they are without symptoms; however, it may cause intrathoracic problems therefore it is important for radiologists and physicians to identify to prevent of excessive intervention and treatment during imaging diagnostic techniques of thoracic problems. In this report, we provide the case of a rare presentation of an intrathoracic rib in a 3-year-old boy arising from the inferior portion of a second rib based on findings from computed tomography. To our knowledge, this is only the second reported case of this type of intrathoracic rib that demonstrated with computed tomography.

  18. Diffraction scattering computed tomography: a window into the structures of complex nanomaterials

    PubMed Central

    Birkbak, M. E.; Leemreize, H.; Frølich, S.; Stock, S. R.

    2015-01-01

    Modern functional nanomaterials and devices are increasingly composed of multiple phases arranged in three dimensions over several length scales. Therefore there is a pressing demand for improved methods for structural characterization of such complex materials. An excellent emerging technique that addresses this problem is diffraction/scattering computed tomography (DSCT). DSCT combines the merits of diffraction and/or small angle scattering with computed tomography to allow imaging the interior of materials based on the diffraction or small angle scattering signals. This allows, e.g., one to distinguish the distributions of polymorphs in complex mixtures. Here we review this technique and give examples of how it can shed light on modern nanoscale materials. PMID:26505175

  19. High precision semi-automated vertebral height measurement using computed tomography: A phantom study.

    PubMed

    Tan, Sovira; Yao, Jianhua; Yao, Lawrence; Ward, Michael M

    2012-01-01

    The measurement of vertebral heights is necessary for the evaluation of many disorders affecting the spine. High precision is particularly important for longitudinal studies where subtle changes are to be detected. Computed tomography (CT) is the modality of choice for high precision studies. Radiography and dual emission X-ray absorptiometry (DXA) use 2D images to assess 3D structures, which can result in poor visualization due to the superimposition of extraneous anatomical objects on the same 2D space. We present a semi-automated computer algorithm to measure vertebral heights in the 3D space of a CT scan. The algorithm segments the vertebral bodies, extracts their end plates and computes vertebral heights as the mean distance between end plates. We evaluated the precision of our algorithm using repeat scans of an anthropomorphic vertebral phantom. Our method has high precision, with a coefficient of variation of only 0.197% and Bland-Altmann 95% limits of agreement of [-0.11, 0.13] mm. For local heights (anterior, middle, posterior) the algorithm was up to 4.2 times more precise than a manual mid-sagittal plane method.

  20. Virtual tomography: a new approach to efficient human-computer interaction for medical imaging

    NASA Astrophysics Data System (ADS)

    Teistler, Michael; Bott, Oliver J.; Dormeier, Jochen; Pretschner, Dietrich P.

    2003-05-01

    By utilizing virtual reality (VR) technologies the computer system virtusMED implements the concept of virtual tomography for exploring medical volumetric image data. Photographic data from a virtual patient as well as CT or MRI data from real patients are visualized within a virtual scene. The view of this scene is determined either by a conventional computer mouse, a head-mounted display or a freely movable flat panel. A virtual examination probe is used to generate oblique tomographic images which are computed from the given volume data. In addition, virtual models can be integrated into the scene such as anatomical models of bones and inner organs. virtusMED has shown to be a valuable tool to learn human anaotomy and to udnerstand the principles of medical imaging such as sonography. Furthermore its utilization to improve CT and MRI based diagnosis is very promising. Compared to VR systems of the past, the standard PC-based system virtusMED is a cost-efficient and easily maintained solution providing a highly intuitive time-saving user interface for medical imaging.

  1. Stafne bone cavity and cone-beam computed tomography: a report of two cases.

    PubMed

    Venkatesh, Elluru

    2015-06-01

    In 1942 Stafne reported 35 asymptomatic, radiolucent cavities that were unilaterally located in the posterior region of the mandible between the mandibular angle and the third molar, and below the mandibular canal. The term Stafne bone cavity (SBC) is now used for such asymptomatic lingual bone depressions of the lower jaw. Since then there have been many reports of SBCs but very fews tudies have used cone-beam computed tomography (CBCT) for their diagnosis. The aim of this paper is to describe the clinical and radiological characteristics of two cases of SBCs and the importance of limited CBCT in confirming the diagnosis.

  2. Dual energy computed tomography: a novel technique for diagnosis of gout.

    PubMed

    Ahmad, Zohra; Gupta, Arun Kumar; Sharma, Raju; Bhalla, Ashu Seith; Kumar, Uma; Sreenivas, V

    2016-09-01

    To evaluate the sensitivity and specificity of dual energy computed tomography (DECT) for diagnosing gout compared with a composite gold standard (CGS) comprising joint aspiration and/or American College of Rheumatology clinico-radiographic criteria. Ninety patients of suspected gout underwent radiography and DECT of bilateral feet and knees. Radiographs and non-contrast CT (NCCT) were assessed for morphological characteristics, following which DECT was used to identify urate deposits. With CGS as a reference (n = 90), sensitivity of radiographs was 15% (95% confidence interval [CI]: 6-27%) while specificity was 100% (95% CI: 90-100%). Sensitivity of NCCT was 26% (95% CI: 15-40%) while specificity was 97% (95% CI: 85-99%). Sensitivity of DECT was 82% (95% CI: 68-90%) while specificity was 89% (95% CI: 73-96%). Fifty-five patients underwent joint aspiration. Sensitivity and specificity of radiographs and NCCT with aspiration as a reference (n = 55) were not much different from that of CGS. However, DECT showed a higher sensitivity of 100% (95% CI: 86-100%) and a lower specificity of 48% (95%CI: 28-68%) with aspiration alone. Dual energy computed tomography had higher sensitivity compared to conventional imaging with CGS as a reference; however, its specificity dropped with aspiration as a reference. It may be a useful adjunct for the diagnosis of gout, especially in the acute and inter-critical stage. © 2016 Asia Pacific League of Associations for Rheumatology and John Wiley & Sons Australia, Ltd.

  3. Stimulated dual-band infrared computed tomography: A tool to inspect the aging infrastructure

    SciTech Connect

    Del Grande, N.K.; Durbin, P.F.

    1995-06-27

    The authors have developed stimulated dual-band infrared (IR) computed tomography as a tool to inspect the aging infrastructure. The system has the potential to locate and quantify structural damage within airframes and bridge decks. Typically, dual-band IR detection methods improve the signal-to-noise ratio by a factor of ten, compared to single-band IR detection methods. They conducted a demonstration at Boeing using a uniform pulsed-heat source to stimulate IR images of hidden defects in the 727 fuselage. The dual-band IR camera and image processing system produced temperature, thermal inertia, and cooling-rate maps. In combination, these maps characterized the defect site, size, depth, thickness and type. The authors quantified the percent metal loss from corrosion above a threshold of 5%, with overall uncertainties of 3%. Also, they conducted a feasibility study of dual-band IR thermal imaging for bridge deck inspections. They determined the sites and relative concrete displacement of 2-in. and 4-in. deep delaminations from thin styrofoam implants in asphalt-covered concrete slabs. They demonstrated the value of dual-band IR computed tomography to quantify structural damage within flash-heated airframes and naturally-heated bridge decks.

  4. Radiation doses in cone-beam breast computed tomography: A Monte Carlo simulation study

    SciTech Connect

    Yi Ying; Lai, Chao-Jen; Han Tao; Zhong Yuncheng; Shen Youtao; Liu Xinming; Ge Shuaiping; You Zhicheng; Wang Tianpeng; Shaw, Chris C.

    2011-02-15

    Purpose: In this article, we describe a method to estimate the spatial dose variation, average dose and mean glandular dose (MGD) for a real breast using Monte Carlo simulation based on cone beam breast computed tomography (CBBCT) images. We present and discuss the dose estimation results for 19 mastectomy breast specimens, 4 homogeneous breast models, 6 ellipsoidal phantoms, and 6 cylindrical phantoms. Methods: To validate the Monte Carlo method for dose estimation in CBBCT, we compared the Monte Carlo dose estimates with the thermoluminescent dosimeter measurements at various radial positions in two polycarbonate cylinders (11- and 15-cm in diameter). Cone-beam computed tomography (CBCT) images of 19 mastectomy breast specimens, obtained with a bench-top experimental scanner, were segmented and used to construct 19 structured breast models. Monte Carlo simulation of CBBCT with these models was performed and used to estimate the point doses, average doses, and mean glandular doses for unit open air exposure at the iso-center. Mass based glandularity values were computed and used to investigate their effects on the average doses as well as the mean glandular doses. Average doses for 4 homogeneous breast models were estimated and compared to those of the corresponding structured breast models to investigate the effect of tissue structures. Average doses for ellipsoidal and cylindrical digital phantoms of identical diameter and height were also estimated for various glandularity values and compared with those for the structured breast models. Results: The absorbed dose maps for structured breast models show that doses in the glandular tissue were higher than those in the nearby adipose tissue. Estimated average doses for the homogeneous breast models were almost identical to those for the structured breast models (p=1). Normalized average doses estimated for the ellipsoidal phantoms were similar to those for the structured breast models (root mean square (rms

  5. Head trauma evaluated by magnetic resonance and computed tomography: a comparison

    SciTech Connect

    Han, J.G.; Kaufman, B.; Alfidi, R.J.

    1984-01-01

    Magnetic resonance (MR) images and computed tomograms of 25 patients with head trauma were compared. MR proved to be superior in many ways for demonstrating extracerebral as well as intracerebral traumatic lesions. Isodense subdural hemotomas, which present a diagnostic dilemma on CT images were clearly seen on MR, regardless of their varying CT densities. In a case of epidural hematoma, the dura mater was shown directly as nearly devoid of signal on MR. Direct coronal images provided excellent visualization of extracerebral collections along the peritentorial space and subtemporal area. In a patient with intracerebral hematoma CT failed to demonstrate residual parenchymal changes in a 3-month follow-up study, but MR clearly depicted the abnormalities. The superiority of MR over CT was also well illustrated in a patient with post-traumatic osteomyelitis of the calvarium.

  6. Laboratory x-ray micro-computed tomography: a user guideline for biological samples

    PubMed Central

    2017-01-01

    Abstract Laboratory x-ray micro–computed tomography (micro-CT) is a fast-growing method in scientific research applications that allows for non-destructive imaging of morphological structures. This paper provides an easily operated “how to” guide for new potential users and describes the various steps required for successful planning of research projects that involve micro-CT. Background information on micro-CT is provided, followed by relevant setup, scanning, reconstructing, and visualization methods and considerations. Throughout the guide, a Jackson's chameleon specimen, which was scanned at different settings, is used as an interactive example. The ultimate aim of this paper is make new users familiar with the concepts and applications of micro-CT in an attempt to promote its use in future scientific studies. PMID:28419369

  7. Neutron Stimulated Emission Computed Tomography: A New Technique for Spectroscopic Medical Imaging

    NASA Astrophysics Data System (ADS)

    Kapadia, A. J.

    Neutron stimulated emission computed tomography (NSECT) is being developed as a new medical-imaging technique to quantify spatial distributions of elements in a sample through inelastic scattering of fast neutrons and detection of the resulting gamma rays. It has the potential to diagnose several disorders in the human body that are characterized by changes in element concentration in the diseased tissue. NSECT is sensitive to several naturally occurring elements in the human body that demonstrate concentration changes in the presence of diseases. NSECT, therefore, has the potential to noninvasively diagnose such disorders with radiation dose that is comparable to other ionizing imaging modalities. This chapter discusses the development and progress of NSECT and presents an overview of the current status of the imaging technique.

  8. [Distribution pattern of density in lumbar vertebra studied with computed tomography: a study of histogram plot].

    PubMed

    Tanno, M; Yamada, H; Kazuo, E; Hayashida, K; Ide, H; Kurihara, N; Mashima, Y; Chiba, K

    1989-07-01

    The bone mineral status of the cancellous bone in the lumbar vertebrae was evaluated by analysing density histograms and measuring the mean density by computed tomography. The results obtained were as follows: (a) the distribution pattern of bone density in lumbar vertebrae revealed a normal distribution. (b) high correlation coefficients between peak density (r = -0.79) or mean density (r = -0.77) and age was obtained in males, whereas peak densities in females were maintained well at ages younger than 50 years and peak densities abruptly decreased after 50 years of age. Osteoporotic vertebrae, in which multiple osteosclerotic changes were observed, had several peak densities and did not show normal density distribution pattern. These results indicated that our methods combining analysis of density histograms and measurement of mean density are useful to evaluate the bone mineral status.

  9. Rare appearance of an odontogenic myxoma in cone-beam computed tomography: a case report

    PubMed Central

    Dabbaghi, Arash; Nikkerdar, Nafiseh; Bayati, Soheyla; Golshah, Amin

    2016-01-01

    Odontogenic myxoma (OM) is an infiltrative benign bone tumor that occurs almost exclusively in the facial skeleton. The radiographic characteristics of odontogenic myxoma may produce several patterns, making diagnosis difficult. Cone-beam computed tomography (CBCT) may prove extremely useful in clarifying the intraosseous extent of the tumor and its effects on surrounding structures. Here, we report a case of odontogenic myxoma of the mandible in a 27-year-old female. The patient exhibited a slight swelling in the left mandible. Surgical resection was performed. No recurrence was noted. In the CBCT sections, we observed perforation of the cortical plate and radiopaque line that extended from the periosteum, resembling "sunray" appearance—a rare feature of OM—which could not be assessed by panoramic radiography. PMID:27092217

  10. [Dynamic cerebral computed tomography. A contribution to the nosology of cerebral space-occupying processes?].

    PubMed

    Westphal, M

    1983-12-01

    Dynamic cerebral studies were carried out in 21 patients with cerebral abnormalities. Thirteen had tumours and eight showed vascular abnormalities. In most cases the diagnosis was confirmed by histology, but occasionally by angiography or by computed tomography and the clinical course. Dynamic cerebral studies were performed, involving the production of concentration-time curves following bolus injection of ordinary contrast medium. The type of contrast enhancement gave a better indication of the nature of the lesion. The method can be used together with the more common type of investigations, such as plain scans and contrast scans. The small number of patients requires further studies with larger numbers; for this a multi-centric study would be suitable.

  11. Measurement of breast tissue composition with dual energy cone-beam computed tomography: A postmortem study

    SciTech Connect

    Ding Huanjun; Ducote, Justin L.; Molloi, Sabee

    2013-06-15

    Purpose: To investigate the feasibility of a three-material compositional measurement of water, lipid, and protein content of breast tissue with dual kVp cone-beam computed tomography (CT) for diagnostic purposes. Methods: Simulations were performed on a flat panel-based computed tomography system with a dual kVp technique in order to guide the selection of experimental acquisition parameters. The expected errors induced by using the proposed calibration materials were also estimated by simulation. Twenty pairs of postmortem breast samples were imaged with a flat-panel based dual kVp cone-beam CT system, followed by image-based material decomposition using calibration data obtained from a three-material phantom consisting of water, vegetable oil, and polyoxymethylene plastic. The tissue samples were then chemically decomposed into their respective water, lipid, and protein contents after imaging to allow direct comparison with data from dual energy decomposition. Results: Guided by results from simulation, the beam energies for the dual kVp cone-beam CT system were selected to be 50 and 120 kVp with the mean glandular dose divided equally between each exposure. The simulation also suggested that the use of polyoxymethylene as the calibration material for the measurement of pure protein may introduce an error of -11.0%. However, the tissue decomposition experiments, which employed a calibration phantom made out of water, oil, and polyoxymethylene, exhibited strong correlation with data from the chemical analysis. The average root-mean-square percentage error for water, lipid, and protein contents was 3.58% as compared with chemical analysis. Conclusions: The results of this study suggest that the water, lipid, and protein contents can be accurately measured using dual kVp cone-beam CT. The tissue compositional information may improve the sensitivity and specificity for breast cancer diagnosis.

  12. Measurement of breast tissue composition with dual energy cone-beam computed tomography: A postmortem study

    PubMed Central

    Ding, Huanjun; Ducote, Justin L.; Molloi, Sabee

    2013-01-01

    Purpose: To investigate the feasibility of a three-material compositional measurement of water, lipid, and protein content of breast tissue with dual kVp cone-beam computed tomography (CT) for diagnostic purposes. Methods: Simulations were performed on a flat panel-based computed tomography system with a dual kVp technique in order to guide the selection of experimental acquisition parameters. The expected errors induced by using the proposed calibration materials were also estimated by simulation. Twenty pairs of postmortem breast samples were imaged with a flat-panel based dual kVp cone-beam CT system, followed by image-based material decomposition using calibration data obtained from a three-material phantom consisting of water, vegetable oil, and polyoxymethylene plastic. The tissue samples were then chemically decomposed into their respective water, lipid, and protein contents after imaging to allow direct comparison with data from dual energy decomposition. Results: Guided by results from simulation, the beam energies for the dual kVp cone-beam CT system were selected to be 50 and 120 kVp with the mean glandular dose divided equally between each exposure. The simulation also suggested that the use of polyoxymethylene as the calibration material for the measurement of pure protein may introduce an error of −11.0%. However, the tissue decomposition experiments, which employed a calibration phantom made out of water, oil, and polyoxymethylene, exhibited strong correlation with data from the chemical analysis. The average root-mean-square percentage error for water, lipid, and protein contents was 3.58% as compared with chemical analysis. Conclusions: The results of this study suggest that the water, lipid, and protein contents can be accurately measured using dual kVp cone-beam CT. The tissue compositional information may improve the sensitivity and specificity for breast cancer diagnosis. PMID:23718593

  13. The 100 most-cited original articles in cardiac computed tomography: A bibliometric analysis.

    PubMed

    O'Keeffe, Michael E; Hanna, Tarek N; Holmes, Davis; Marais, Olivia; Mohammed, Mohammed F; Clark, Sheldon; McLaughlin, Patrick; Nicolaou, Savvas; Khosa, Faisal

    2016-01-01

    Bibliometric analysis is the application of statistical methods to analyze quantitative data about scientific publications. It can evaluate research performance, author productivity, and manuscript impact. To the best of our knowledge, no bibliometric analysis has focused on cardiac computed tomography (CT). The purpose of this paper was to compile a list of the 100 most-cited articles related to cardiac CT literature using Scopus and Web of Science (WOS). A list of the 100 most-cited articles was compiled by order of citation frequency, as well a list of the top 10 most-cited guideline and review articles and the 20 most-cited articles of the years 2014-2015. The database of 100 most-cited articles was analyzed to identify characteristics of highly cited publications. For each manuscript, the number of authors, study design, size of patient cohort and departmental affiliations were cataloged. The 100 most-cited articles were published from 1990 to 2012, with the majority (53) published between 2005 and 2009. The total number of citations varied from 3354 to 196, and the number of citations per year varied from 9.5 to 129.0 with a median and mean of 30.9 and 38.7, respectively. The majority of publications had a study patients sample size of 200 patients or less. The USA and Germany were the nations with the highest number of frequently cited publications. This bibliometric analysis provides insights on the most-cited articles published on the subject of cardiac CT and calcium volume, thus helping to characterize the field and guide future research. Copyright © 2016 Society of Cardiovascular Computed Tomography. Published by Elsevier Inc. All rights reserved.

  14. Osteoid osteoma - radiofrequency ablation treatment guided by computed tomography: a case series.

    PubMed

    Endo, Rosana Raquel; Gama, Natalia Fabris; Nakagawa, Suely Akiko; Tyng, Chiang Jeng; Chung, Wu Tu; Pinto, Fábio Fernando Eloi

    2017-01-01

    The osteoid osteoma is a benign primary bone tumor that affects mainly males in the second and third decades of life. Radiographic findings show a radiolucent nidus surrounded by reactive sclerotic bone, particularly in the long bones of the lower extremity. Clinically, it presents persistent pain, which is worse at night and improves with salicylates. It can be a self-limiting injury, with an average duration of three years, but because of pain intensity and intolerance to prolonged use of nonsteroidal anti-inflammatories, surgical treatment is an option. The diagnosis is suspected according to the history and radiographic findings, and the confirmation is made by histological analysis. The traditional surgical treatment is the complete excision of the nidus, but some disadvantages have been described, such as difficulties in localizing the lesion and risk of fracture during the procedure, hospital stay for pain control, and unfavorable esthetic outcome. The authors report a series of cases treated with thermal radiofrequency ablation guided by computed tomography in this service. It is a safe and an effective percutaneous method that aims to cure, minimizing the trauma and morbidity when compared with the conventional block-resection method.

  15. Image-Guided Drug Delivery with Single-Photon Emission Computed Tomography: A Review of Literature

    PubMed Central

    Chakravarty, Rubel; Hong, Hao; Cai, Weibo

    2014-01-01

    Tremendous resources are being invested all over the world for prevention, diagnosis, and treatment of various types of cancer. Successful cancer management depends on accurate diagnosis of the disease along with precise therapeutic protocol. The conventional systemic drug delivery approaches generally cannot completely remove the competent cancer cells without surpassing the toxicity limits to normal tissues. Therefore, development of efficient drug delivery systems holds prime importance in medicine and healthcare. Also, molecular imaging can play an increasingly important and revolutionizing role in disease management. Synergistic use of molecular imaging and targeted drug delivery approaches provides unique opportunities in a relatively new area called `image-guided drug delivery' (IGDD). Single-photon emission computed tomography (SPECT) is the most widely used nuclear imaging modality in clinical context and is increasingly being used to guide targeted therapeutics. The innovations in material science have fueled the development of efficient drug carriers based on, polymers, liposomes, micelles, dendrimers, microparticles, nanoparticles, etc. Efficient utilization of these drug carriers along with SPECT imaging technology have the potential to transform patient care by personalizing therapy to the individual patient, lessening the invasiveness of conventional treatment procedures and rapidly monitoring the therapeutic efficacy. SPECT-IGDD is not only effective for treatment of cancer but might also find utility in management of several other diseases. Herein, we provide a concise overview of the latest advances in SPECT-IGDD procedures and discuss the challenges and opportunities for advancement of the field. PMID:25182469

  16. Three-dimensional maxillary and mandibular regional superimposition using cone beam computed tomography: a validation study.

    PubMed

    Koerich, L; Burns, D; Weissheimer, A; Claus, J D P

    2016-05-01

    This study aimed to validate a novel method for fast regional superimposition of cone beam computed tomography (CBCT) scans. The method can be used with smaller field of view scans, thereby allowing for a lower radiation dose. This retrospective study used two dry skulls and secondary data from 15 patients who had more than one scan taken using the same machine. Two observers tested two types of regional voxel-based superimposition: maxillary and mandibular. The registration took 10-15s. Three-dimensional surface models of the maxillas and mandibles were generated via standardized threshold segmentation, and the accuracy and reproducibility of the superimpositions were assessed using the iterative closest point technique to measure the root mean square (RMS) distance between the images. Five areas were measured and a RMS≤0.25 was considered successful. Descriptive statistics and the intra-class correlation coefficient (ICC) were used to compare the intra-observer measurement reproducibility. The ICC was ≥0.980 for all of the variables and the highest RMS found was 0.241. The inter-observer reproducibility was assessed case by case and was perfect (RMS 0) for 68% (23 out of 34) of the superimpositions done and not clinically significant (RMS≤0.25) for the other 32%. The method is fast, accurate, and reproducible and is an alternative to cranial base superimposition.

  17. Assessment of Mandibular Distraction Regenerate Using Ultrasonography and Cone Beam Computed Tomography: A Clinical Study

    PubMed Central

    Dabas, Jitender; Mohanty, Sujata; Chaudhary, Zainab; Rani, Amita

    2015-01-01

    Distraction osteogenesis (DO) is becoming a popular method of reconstruction for maxillofacial bony deformities or defects secondary to trauma or surgical tumor ablation. However, the technique is very sensitive in terms of the rate and rhythm of distraction. Because of this, there is a need for monitoring of the distraction regenerate during the distraction as well as the consolidation period. The present study was conducted to assess the regenerate using two imaging modalities, namely, ultrasonography (USG) and cone beam computed tomography (CBCT) to determine their relative efficacies and to weigh their clinical usefulness in assessment of DO regenerate. The study was conducted on 12 patients (18 sites) who underwent mandibular distraction for correction of facial deformities. The results showed that overall USG correlated better with the condition of regenerate (r = 0.606) as compared with CBCT (r = 0.476). However, USG was less effective as compared with CBCT in assessing the regenerate once corticomedullary differentiation occurred in the bone. PMID:26889351

  18. Computed tomography: a powerful imaging technique in the fields of dimensional metrology and quality control

    NASA Astrophysics Data System (ADS)

    Probst, Gabriel; Boeckmans, Bart; Dewulf, Wim; Kruth, Jean-Pierre

    2016-05-01

    X-ray computed tomography (CT) is slowly conquering its space in the manufacturing industry for dimensional metrology and quality control purposes. The main advantage is its non-invasive and non-destructive character. Currently, CT is the only measurement technique that allows full 3D visualization of both inner and outer features of an object through a contactless probing system. Using hundreds of radiographs, acquired while rotating the object, a 3D representation is generated and dimensions can be verified. In this research, this non-contact technique was used for the inspection of assembled components. A dental cast model with 8 implants, connected by a screwed retained bar made of titanium. The retained bar includes a mating interface connection that should ensure a perfect fitting without residual stresses when the connection is fixed with screws. CT was used to inspect the mating interfaces between these two components. Gaps at the connections can lead to bacterial growth and potential inconvenience for the patient who would have to face a new surgery to replace his/hers prosthesis. With the aid of CT, flaws in the design or manufacturing process that could lead to gaps at the connections could be assessed.

  19. [Brain abscesses. Value of computed tomography. A review of seven cases (author's transl)].

    PubMed

    Leriche, B; Boucetta, M; Jourdan, P; Desgeorges, M

    1980-01-01

    Based on a series of seven cases of subtentorial abscess, the authors analyze the results of different methods of exploration. Though in certain clinical conditions (intracranial hypertension and meningeal infections) the etiology is of no consequence, in most cases of definite diagnosis can be made of a space-occupying lesion by the use of EEG, arteriography, and scintigraphy examinations, without establishing the precise nature of the affection. As expected, computed tomography appears to be the most reliable examination. Diagnosis was confirmed by this method in 6 of the 7 cases, and it also enabled the number, size, and location of the lesions to be determined. Typical appearances after injection of an iodized contrast medium revealed the development of an abscess following the intracerebral infection, and determined the time for surgical intervention. In spite of intensive care and antibiotic therapy, an abscess remains a "delayed-action bomb", with poor prognosis, requiring drainage or surgical excision as soon as conditions are appropriate. The mortality and morbidity of this rare, and therefore poorly recognized, affection should improve with systematic use of the scanner during meningeal infections.

  20. Fatal Clostridium perfringens septicemia suggested by postmortem computed tomography: A medico-legal autopsy case report.

    PubMed

    Yamaguchi, Rutsuko; Makino, Yohsuke; Chiba, Fumiko; Motomura, Ayumi; Inokuchi, Go; Yajima, Daisuke; Iwase, Hirotatro

    2015-08-01

    We report a fatal case of suspected Clostridium (Cl.) perfringens septicemia in a previously healthy woman in her eighties. At first, she presented at the hospital complaining of upper abdominal discomfort and vomiting, and was discharged the next day after ruling out any fatal conditions. However, her condition deteriorated approximately 10h after discharge and she died shortly after. The postmortem computed tomography (PMCT) performed 29h postmortem revealed an excessive systemic gas accumulation compared with the postmortem external appearance and time elapsed since her death, which suggested the presence of a gas-forming infection. Histopathological examination showed diffuse proliferation of Gram-positive bacilli in almost all the organ tissues, especially in blood vessels. Along with these findings, hyperthermia 3h postmortem, and severe anemia and thrombocytopenia without an obvious site of hemorrhage suggested hemolysis due to Cl. perfringens septicemia. These findings suggested the diagnosis before performing the conventional autopsy. To the best of our knowledge, this is the first case report to describe PMCT findings of gas-forming infection and septicemia in contrast with the external appearance and histopathological findings in a medico-legal autopsy setting. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  1. A novel method to measure femoral component migration by computed tomography: a cadaver study.

    PubMed

    Boettner, Friedrich; Sculco, Peter; Lipman, Joseph; Renner, Lisa; Faschingbauer, Martin

    2016-06-01

    Radiostereometric analysis (RSA) is the most accurate technique to measure implant migration. However, it requires special equipment, technical expertise and analysis software and has not gained wide acceptance. The current paper analyzes a novel method to measure implant migration utilizing widely available computer tomography (CT). Three uncemented total hip replacements were performed in three human cadavers and six tantalum beads were inserted into the femoral bone similar to RSA. Six different 28 mm heads (-3, 0, 2.5, 5.0, 7.5 and 10 mm) were added to simulate five reproducible translations (maximum total point migration) of the center of the head. Implant migration was measured in a 3-D analysis software (Geomagic Studio 7). Repeat manual reconstructions of the center of the head were performed by two investigators to determine repeatability and accuracy. The accuracy of measurements between the centers of two head sizes was 0.11 mm with a CI 95 % of 0.22 mm. The intra-observer repeatability was 0.13 mm (CI 95 % 0.25 mm). The interrater-reliability was 0.943. CT based measurement of head displacement in a cadaver model were highly accurate and reproducible.

  2. Quantifying Heterogeneity in Emphysema from High Resolution Computed Tomography: A Lung Tissue Research Consortium Study

    PubMed Central

    Yilmaz, Cuneyt; Dane, Dan M.; Patel, Nova C.; Hsia, Connie C.W.

    2012-01-01

    Rationale and Objective To quantify spatial distribution of emphysema using high-resolution computed tomography (HRCT), we applied semi-automated analysis with internal attenuation calibration to measure regional air volume, tissue volume, and fractional tissue volume (FTV=tissue/[air+tissue] volume) in well-characterized patients studied by the Lung Tissue Research Consortium (LTRC). Methods HRCT was obtained at supine end-inspiration and end-expiration, and prone end-inspiration from 31 patients with mild, moderate, severe, or very severe emphysema (stages II–V, FEV1>75%, 51–75%, 21–50% and ≤20% predicted, respectively). Control data were from 20 healthy non-smokers (stage I). Each lobe was analyzed separately. Heterogeneity of FTV was assessed from coefficients of variation (CV) within and among lobes, and the kurtosis and skewness of FTV histograms. Results In emphysema, lobar air volume increased up to 177% except in the right middle lobe. Lobar tissue volume increased up to 107% in mild-moderate stages then normalized in advanced stages. Normally, FTV was up to 82% higher in lower than upper lobes. In mild-moderate emphysema, lobar FTV increased by up to 74% above normal at supine inspiration. In severe emphysema FTV declined below normal in all lobes and positions in correlation with pulmonary function (p<0.05). Markers of FTV heterogeneity increased steadily with disease stage in correlation with pulmonary function (p<0.05); the pattern is distinct from that seen in interstitial lung disease (ILD). Conclusion CT-derived biomarkers differentiate the spatial patterns of emphysema distribution and heterogeneity from that in ILD. Early emphysema is associated with elevated tissue volume and FTV, consistent with hyperemia, inflammation or atelectasis. PMID:23122057

  3. Patients with osteosarcoma with a single pulmonary nodule on computed tomography: a single-institution experience.

    PubMed

    Fernandez-Pineda, Israel; Daw, Najat C; McCarville, Beth; Emanus, Liza J; Rao, Bhaskar N; Davidoff, Andrew M; Shochat, Stephen J

    2012-06-01

    The purpose of this study is to determine if patients with osteosarcoma (OS) with metachronous metastatic pulmonary disease presenting with a single pulmonary nodule (SPN) on computed tomography (CT) were found to have other lesions at the time of thoracotomy. Data were collected retrospectively on consecutive patients with OS treated at our institution from 1982 to 2007. Patients with no evidence of disease at the end of initial therapy who subsequently relapsed in the lung were identified. In our study, 16 (8%) of 198 patients with OS with metachronous metastatic pulmonary disease presented with a SPN on CT scan. In all patients, only 1 metastatic nodule for OS was found at the time of thoracotomy. The median time between diagnosis and first lung relapse was 23.8 months (range, 4-80 months). Eleven patients (68.7%) subsequently had a second lung relapse, but only 3 patients had involvement of the ipsilateral lung (mean time interval between first and second pulmonary relapses of 17 months; range, 2-44 months). Five-year overall survival from diagnosis was 56.2%. Seven patients (43.8%) died of disease progression. In our experience, patients with OS with metachronous metastatic pulmonary disease presenting with a SPN on CT were not found to have additional malignant lesions at the time of thoracotomy. Consideration should be given in this group of selected patients to use a minimally invasive approach to nodule removal with image-guided localization, if needed, rather than open thoracotomy because ipsilateral metastases are not likely to be found. Copyright © 2012 Elsevier Inc. All rights reserved.

  4. Clinical significance of visceral adiposity assessed by computed tomography: A Japanese perspective

    PubMed Central

    Ryo, Miwa; Kishida, Ken; Nakamura, Tadashi; Yoshizumi, Tohru; Funahashi, Tohru; Shimomura, Iichiro

    2014-01-01

    Abdominal obesity, rather than total amount of fat, is linked to obesity-related disorders. Visceral adiposity is an important component of obesity-related disorders in Japanese individuals with a mild degree of adiposity compared with Western subjects. In 1983, our group reported techniques for body fat analysis using computed tomography (CT) and established the concept of visceral fat obesity in which intra-abdominal fat accumulation is an important factor in the development of obesity-related complications, such as diabetes, lipid disorders, hypertension and atherosclerosis. Our group also established ideal imaging conditions for determining abdominal fat area at the umbilical level CT scan. Visceral fat area (VFA) measured in a single slice at L4 level correlated significantly with the total abdominal visceral fat volume measured on multislice CT scan. In a large-scale study of a Japanese population, the mean number of obesity-related cardiovascular risk factors (hypertension, low high-density lipoprotein cholesterolemia and/or hypertriglyceridemia, and hyperglycemia) was greater than 1.0 at 100 cm2 of VFA, irrespective of gender, age and body mass index. Our group also demonstrated that reduction of visceral fat accumulation subsequent to voluntary lifestyle modification, “Hokenshido”, correlated with a decrease in the number of obesity-related cardiovascular risk factors. It is important to select the most appropriate subjects from the general population (e.g., non-obese subjects with a cluster of risk factors for the metabolic syndrome) that are most suitable for body weight reduction, with the goal of preventing atherosclerotic cardiovascular diseases. PMID:25071881

  5. Vascular air embolism after contrast administration on 64 row multiple detector computed tomography: A prospective analysis.

    PubMed

    Sodhi, Kushaljit S; Saxena, Akshay K; Chandrashekhar, Guruprasadh; Bhatia, Anmol; Singhi, Sunit; Agarwal, Ritesh; Khandelwal, Niranjan

    2015-01-01

    Vascular air embolism is being progressively reported as a nonfatal event with increase in use of computed tomography (CT) as a diagnostic modality. This study was undertaken to study the frequency and site of vascular air embolism in patients undergoing contrast-enhanced CT (CECT) and analyze CT parameters that influence its prevalence and final outcome. This was a prospective study approved by departmental ethics committee. Presence and location of air emboli in 200 patients who underwent CT scan of chest on a 64 detector scanner was recorded. We analyzed the role of various factors that could influence the prevalence of air embolism after injection of contrast in CECT scans. These factors included the amount of contrast injected, rate of flow of injection of contrast, site of injection of contrast, and size of intravenous access line. Iatrogenic vascular air emboli were seen in 14 patients (7% of total). The locations of air emboli were main pulmonary artery in 12 (6% of total), left brachiocephalic vein in 3 (1.5% of total), right atrial appendage in 4 (2% of total), and superior vena cava (SVC) in 1 (0.5%) patient. There was no association between volume of contrast, flow rate, site and size of intravenous access, and presence of air emboli. Radiologists as well as referring physicians should be aware of vascular air embolism, which can occur after contrast injection in patients undergoing CT scan. Age, volume of contrast, flow rate of pressure injector, and site and size of venous cannula do not influence the likelihood or incidence of detection of venous air emboli on CT scans.

  6. Respiratory triggered 4D cone-beam computed tomography: A novel method to reduce imaging dose

    SciTech Connect

    Cooper, Benjamin J.; O'Brien, Ricky T.; Keall, Paul J.; Balik, Salim; Hugo, Geoffrey D.

    2013-04-15

    Purpose: A novel method called respiratory triggered 4D cone-beam computed tomography (RT 4D CBCT) is described whereby imaging dose can be reduced without degrading image quality. RT 4D CBCT utilizes a respiratory signal to trigger projections such that only a single projection is assigned to a given respiratory bin for each breathing cycle. In contrast, commercial 4D CBCT does not actively use the respiratory signal to minimize image dose. Methods: To compare RT 4D CBCT with conventional 4D CBCT, 3600 CBCT projections of a thorax phantom were gathered and reconstructed to generate a ground truth CBCT dataset. Simulation pairs of conventional 4D CBCT acquisitions and RT 4D CBCT acquisitions were developed assuming a sinusoidal respiratory signal which governs the selection of projections from the pool of 3600 original projections. The RT 4D CBCT acquisition triggers a single projection when the respiratory signal enters a desired acquisition bin; the conventional acquisition does not use a respiratory trigger and projections are acquired at a constant frequency. Acquisition parameters studied were breathing period, acquisition time, and imager frequency. The performance of RT 4D CBCT using phase based and displacement based sorting was also studied. Image quality was quantified by calculating difference images of the test dataset from the ground truth dataset. Imaging dose was calculated by counting projections. Results: Using phase based sorting RT 4D CBCT results in 47% less imaging dose on average compared to conventional 4D CBCT. Image quality differences were less than 4% at worst. Using displacement based sorting RT 4D CBCT results in 57% less imaging dose on average, than conventional 4D CBCT methods; however, image quality was 26% worse with RT 4D CBCT. Conclusions: Simulation studies have shown that RT 4D CBCT reduces imaging dose while maintaining comparable image quality for phase based 4D CBCT; image quality is degraded for displacement based RT 4D

  7. Segmentation and quantification of materials with energy discriminating computed tomography: A phantom study

    PubMed Central

    Le, Huy Q.; Molloi, Sabee

    2011-01-01

    Purpose: To experimentally investigate whether a computed tomography (CT) system based on CdZnTe (CZT) detectors in conjunction with a least-squares parameter estimation technique can be used to decompose four different materials. Methods: The material decomposition process was divided into a segmentation task and a quantification task. A least-squares minimization algorithm was used to decompose materials with five measurements of the energy dependent linear attenuation coefficients. A small field-of-view energy discriminating CT system was built. The CT system consisted of an x-ray tube, a rotational stage, and an array of CZT detectors. The CZT array was composed of 64 pixels, each of which is 0.8×0.8×3 mm. Images were acquired at 80 kVp in fluoroscopic mode at 50 ms per frame. The detector resolved the x-ray spectrum into energy bins of 22–32, 33–39, 40–46, 47–56, and 57–80 keV. Four phantoms were constructed from polymethylmethacrylate (PMMA), polyethylene, polyoxymethylene, hydroxyapatite, and iodine. Three phantoms were composed of three materials with embedded hydroxyapatite (50, 150, 250, and 350 mg∕ml) and iodine (4, 8, 12, and 16 mg∕ml) contrast elements. One phantom was composed of four materials with embedded hydroxyapatite (150 and 350 mg∕ml) and iodine (8 and 16 mg∕ml). Calibrations consisted of PMMA phantoms with either hydroxyapatite (100, 200, 300, 400, and 500 mg∕ml) or iodine (5, 15, 25, 35, and 45 mg∕ml) embedded. Filtered backprojection and a ramp filter were used to reconstruct images from each energy bin. Material segmentation and quantification were performed and compared between different phantoms. Results: All phantoms were decomposed accurately, but some voxels in the base material regions were incorrectly identified. Average quantification errors of hydroxyapatite∕iodine were 9.26∕7.13%, 7.73∕5.58%, and 12.93∕8.23% for the three-material PMMA, polyethylene, and polyoxymethylene phantoms, respectively. The

  8. Quantitative micro-computed tomography: a non-invasive method to assess equivalent bone mineral density.

    PubMed

    Nazarian, Ara; Snyder, Brian D; Zurakowski, David; Müller, Ralph

    2008-08-01

    One of the many applications of micro computed tomography (microCT) is to accurately visualize and quantify cancellous bone microstructure. However, microCT based assessment of bone mineral density has yet to be thoroughly investigated. Specifically, the effects of varying imaging parameters, such as tube voltage (kVp), current (microA), integration time (ms), object to X-ray source distance (mm), projection number, detector array size and imaging media (surrounding the specimen), on the relationship between equivalent tissue density (rhoEQ) and its linear attenuation coefficient (micro) have received little attention. In this study, in house manufactured, hydrogen dipotassium phosphate liquid calibration phantoms (K2HPO4) were employed in addition to a resin embedded hydroxyapatite solid calibration phantoms supplied by Scanco Medical AG Company. Variations in current, integration time and projection number had no effect on the conversion relationship between micro and rhoEQ for the K2HPO4 and Scanco calibration phantoms [p>0.05 for all cases]. However, as expected, variations in scanning tube voltage, object to X-ray source distance, detector array size and imaging media (referring to the solution that surrounds the specimen in the imaging vial) significantly affected the conversion relationship between mu and rhoEQ for K2HPO4 and Scanco calibration phantoms [p<0.05 for all cases]. A multivariate linear regression approach was used to estimate rhoEQ based on attenuation coefficient, tube voltage, object to X-ray source distance, detector array size and imaging media for K2HPO4 liquid calibration phantoms, explaining 90% of the variation in rhoEQ. Furthermore, equivalent density values of bovine cortical bone (converted from attenuation coefficient to equivalent density using the K2HPO4 liquid calibration phantoms) samples highly correlated [R2=0.92] with the ash densities of the samples. In conclusion, Scanco calibration phantoms can be used to assess equivalent

  9. Positron Emission Tomography Computed Tomography: A Guide for the General Radiologist.

    PubMed

    Beadsmoore, Clare; Newman, David; MacIver, Duncan; Pawaroo, Davina

    2015-11-01

    Cancer remains a leading cause of death in Canada and worldwide. Whilst advances in anatomical imaging to detect and monitor malignant disease have continued over the last few decades, limitations remain. Functional imaging, such as positron emission tomography (PET), has improved the sensitivity and specificity in detecting malignant disease. In combination with computed tomography (CT), PET is now commonly used in the oncology setting and is an integral part of many cancer patients' pathways. Although initially the CT component of the study was purely for attenuation of the PET imaging and to provide anatomical coregistration, many centers now combine the PET study with a diagnostic quality contrast enhanced CT to provide one stop staging, thus refining the patient's pathway. The commonest tracer used in everyday practice is FDG (F18-fluorodeoxyglucose). There are many more tracers in routine clinical practice and those with emerging roles, such as 11C-choline, useful in the imaging of prostate cancer; 11C-methionine, useful in imaging brain tumours; C11-acetate, used in imaging hepatocellular carcinomas; 18F-FLT, which can be used as a marker of cellular proliferation in various malignancies; and F18-DOPA and various 68Ga-somatostatin analogues, used in patients with neuroendocrine tumours. In this article we concentrate on FDG PETCT as this is the most commonly available and widely utilised tracer now used to routinely stage a number of cancers. PETCT alters the stage in approximately one-third of patients compared to anatomical imaging alone. Increasingly, PETCT is being used to assess early metabolic response to treatment. Metabolic response can be seen much earlier than a change in the size/volume of the disease which is measured by standard CT imaging. This can aid treatment decisions in both in terms of modifying therapy and in addition to providing important prognostic information. Furthermore, it is helpful in patients with distorted anatomy from surgery

  10. Segmentation and quantification of materials with energy discriminating computed tomography: A phantom study

    SciTech Connect

    Le, Huy Q.; Molloi, Sabee

    2011-01-15

    Purpose: To experimentally investigate whether a computed tomography (CT) system based on CdZnTe (CZT) detectors in conjunction with a least-squares parameter estimation technique can be used to decompose four different materials. Methods: The material decomposition process was divided into a segmentation task and a quantification task. A least-squares minimization algorithm was used to decompose materials with five measurements of the energy dependent linear attenuation coefficients. A small field-of-view energy discriminating CT system was built. The CT system consisted of an x-ray tube, a rotational stage, and an array of CZT detectors. The CZT array was composed of 64 pixels, each of which is 0.8x0.8x3 mm. Images were acquired at 80 kVp in fluoroscopic mode at 50 ms per frame. The detector resolved the x-ray spectrum into energy bins of 22-32, 33-39, 40-46, 47-56, and 57-80 keV. Four phantoms were constructed from polymethylmethacrylate (PMMA), polyethylene, polyoxymethylene, hydroxyapatite, and iodine. Three phantoms were composed of three materials with embedded hydroxyapatite (50, 150, 250, and 350 mg/ml) and iodine (4, 8, 12, and 16 mg/ml) contrast elements. One phantom was composed of four materials with embedded hydroxyapatite (150 and 350 mg/ml) and iodine (8 and 16 mg/ml). Calibrations consisted of PMMA phantoms with either hydroxyapatite (100, 200, 300, 400, and 500 mg/ml) or iodine (5, 15, 25, 35, and 45 mg/ml) embedded. Filtered backprojection and a ramp filter were used to reconstruct images from each energy bin. Material segmentation and quantification were performed and compared between different phantoms. Results: All phantoms were decomposed accurately, but some voxels in the base material regions were incorrectly identified. Average quantification errors of hydroxyapatite/iodine were 9.26/7.13%, 7.73/5.58%, and 12.93/8.23% for the three-material PMMA, polyethylene, and polyoxymethylene phantoms, respectively. The average errors for the four

  11. Preliminary Phase Field Computational Model Development

    SciTech Connect

    Li, Yulan; Hu, Shenyang Y.; Xu, Ke; Suter, Jonathan D.; McCloy, John S.; Johnson, Bradley R.; Ramuhalli, Pradeep

    2014-12-15

    This interim report presents progress towards the development of meso-scale models of magnetic behavior that incorporate microstructural information. Modeling magnetic signatures in irradiated materials with complex microstructures (such as structural steels) is a significant challenge. The complexity is addressed incrementally, using the monocrystalline Fe (i.e., ferrite) film as model systems to develop and validate initial models, followed by polycrystalline Fe films, and by more complicated and representative alloys. In addition, the modeling incrementally addresses inclusion of other major phases (e.g., martensite, austenite), minor magnetic phases (e.g., carbides, FeCr precipitates), and minor nonmagnetic phases (e.g., Cu precipitates, voids). The focus of the magnetic modeling is on phase-field models. The models are based on the numerical solution to the Landau-Lifshitz-Gilbert equation. From the computational standpoint, phase-field modeling allows the simulation of large enough systems that relevant defect structures and their effects on functional properties like magnetism can be simulated. To date, two phase-field models have been generated in support of this work. First, a bulk iron model with periodic boundary conditions was generated as a proof-of-concept to investigate major loop effects of single versus polycrystalline bulk iron and effects of single non-magnetic defects. More recently, to support the experimental program herein using iron thin films, a new model was generated that uses finite boundary conditions representing surfaces and edges. This model has provided key insights into the domain structures observed in magnetic force microscopy (MFM) measurements. Simulation results for single crystal thin-film iron indicate the feasibility of the model for determining magnetic domain wall thickness and mobility in an externally applied field. Because the phase-field model dimensions are limited relative to the size of most specimens used in

  12. ROUTES: a computer program for preliminary route location.

    Treesearch

    S.E. Reutebuch

    1988-01-01

    An analytical description of the ROUTES computer program is presented. ROUTES is part of the integrated preliminary harvest- and transportation-planning software package, PLANS. The ROUTES computer program is useful where grade and sideslope limitations are important in determining routes for vehicular travel. With the program, planners can rapidly identify route...

  13. A computer controlled pulsatile pump: preliminary study.

    PubMed

    Zwarts, M S; Topaz, S R; Jones, D N; Kolff, W J

    1996-12-01

    A Stepper Motor Driven Reciprocating Pump (SDRP) can replace roller pumps and rotary pumps for cardio pulmonary bypass, hemodialysis and regional perfusion. The blood pumping ventricles are basically the same as ventricles used for air driven artificial hearts and ventricular assist devices. The electric stepper motor uses a flexible linkage belt to produce a reciprocating movement, which pushes a hard sphere into the diaphragm of the blood ventricles. The SDRP generates pulsatile flow and has a small priming volume. The preset power level of the motor driver limits the maximum potential outflow pressure, so the driver acts as a safety device. A double pump can be made by connecting two fluid pumping chambers to opposing sides of the motor base. Each pump generates pulsatile flow. Pressure and flow studies with water were undertaken. Preliminary blood studies showed low hemolysis, even when circulating a small amount of blood up to 16 hours.

  14. A Computer Program for Preliminary Data Analysis

    Treesearch

    Dennis L. Schweitzer

    1967-01-01

    ABSTRACT. -- A computer program written in FORTRAN has been designed to summarize data. Class frequencies, means, and standard deviations are printed for as many as 100 independent variables. Cross-classifications of an observed dependent variable and of a dependent variable predicted by a multiple regression equation can also be generated.

  15. Hand-Held Computer Programs for Preliminary Helicopter Design.

    DTIC Science & Technology

    1982-10-01

    programmable calculator a series of programs that give acceptable results during the preliminary phases of the helicopter design process. The project consists of three parts. The first part consists of several short programs and their subroutine form. These programs and subroutines compute density altitude, density, disc area, solidity, tip velocity, induced velocity, coefficient of thrust, tip loss factor, equivalent chord, and ground effect. The second part consists of major subroutines. These subroutines compute profile power, induced power, climb power, parasite power,

  16. Computing and information sciences preliminary engineering design study

    SciTech Connect

    Schroeder, J O; Pearson, E W; Thomas, J J; Brothers, J W; Campbell, W K; DeVaney, D M; Jones, D R; Littlefield, R J; Peterson, M J

    1991-04-01

    This document presents the preliminary design concept for the integrated computing and information system to be included in the Environmental and Molecular Sciences Laboratory (EMSL) at the Pacific Northwest Laboratory, Richland, Washington, for the US Department of Energy (DOE). The EMSL is scheduled for completion and occupancy in 1994 or 1995 and will support the DOE environmental mission, in particular hazardous waste remediation. The focus of the report is on the Computing and Information Sciences engineering task of providing a fully integrated state-of-the-art computing environment for simulation, experimentation and analysis in support of molecular research. The EMSL will house two major research organizations, the Molecular Sciences Research Center (MSRC) and part of the Environmental Sciences Research Center (ESRC). Included in the report is a preliminary description of the computing and information system to be included. The proposed system architecture is based on a preliminary understanding of the EMSL users' needs for computational resources. As users understand more about the scientific challenges they face, the definition of the functional requirements will change. At the same time, the engineering team will be gaining experience with new computing technologies. Accordingly, the design architecture must evolve to reflect this new understanding of functional requirements and enabling technologies. 3 figs., 2 tabs.

  17. Modeling the complete Otto cycle: Preliminary version. [computer programming

    NASA Technical Reports Server (NTRS)

    Zeleznik, F. J.; Mcbride, B. J.

    1977-01-01

    A description is given of the equations and the computer program being developed to model the complete Otto cycle. The program incorporates such important features as: (1) heat transfer, (2) finite combustion rates, (3) complete chemical kinetics in the burned gas, (4) exhaust gas recirculation, and (5) manifold vacuum or supercharging. Changes in thermodynamic, kinetic and transport data as well as model parameters can be made without reprogramming. Preliminary calculations indicate that: (1) chemistry and heat transfer significantly affect composition and performance, (2) there seems to be a strong interaction among model parameters, and (3) a number of cycles must be calculated in order to obtain steady-state conditions.

  18. Prediction of pulmonary function after lung lobectomy by subsegments counting, computed tomography, single photon emission computed tomography and computed tomography: a comparative study.

    PubMed

    Yoshimoto, Kentaro; Nomori, Hiroaki; Mori, Takeshi; Kobayashi, Hironori; Ohba, Yasuomi; Shibata, Hidekatsu; Shiraishi, Shinya; Kobayashi, Toshiaki

    2009-03-01

    The aim of the present study was to determine the optimal method of predicting postoperative pulmonary function (PPF) after lung lobectomy. The forced expiratory volume in 1s (FEV(1)) was measured in 37 patients before and after lobectomy, and the following three methods of predicting the PPF were evaluated: (1) the number of functioning subsegments to be resected were counted (subsegments counting [SC]); (2) the volume of the functioning lung was calculated using CT images (quantitative CT); and (3) perfusion scintigraphy was performed using co-registered single photon emission computed tomography and CT imaging (SPECT/CT). The FEV(1) values predicted using these three methods were then compared with the measured postoperative FEV(1), and the correlations and differences were analyzed. While a paired t-test showed the SPECT/CT method to have the smallest difference between the measured and the predicted FEV(1) values (0.05 l, p=0.33), followed by the quantitative CT method (0.07 l, p=0.07), and finally the SC method (0.15 l, p<0.001), the difference between the two values was not significantly different between the quantitative CT and SPECT/CT method (p=0.22). While the SC method is inferior to both the quantitative CT and the SPECT/CT methods for predicting the PPF after lobectomy, the latter two methods are almost equally accurate.

  19. Diagnosis of simulated condylar bone defects using panoramic radiography, spiral tomography and cone-beam computed tomography: A comparison study

    PubMed Central

    Salemi, Fatemeh; Shokri, Abbas; Baharvand, Maryam

    2015-01-01

    Objectives: Radiographic examination is one of the most important parts of the clinical assessment routine for temporomandibular disorders. The aim of this study was to compare the diagnostic accuracy of cone-beam computed tomography(CBCT) with panoramic radiography and spiral computed tomography for the detection of the simulated mandibular condyle bone lesions. Study Design: The sample consisted of 10 TMJs from 5 dried human skulls. Simulated erosive and osteophytic lesions were created in 3 different sizes using round diamond bur and bone chips, respectively. Panoramic radiography, spiral tomography and cone-beam computed tomography were used in defect detection. Data were statistically analyzed with the Mann-Whitney test. The reliability and degrees of agreement between two observers were also determined by the mean of Cohen’s Kappa analysis. Results: CBCT had a statistically significant superiority than other studied techniques in detection of both erosive and osteophytic lesions with different sizes. There were significant differences between tomography and panoramic in correct detection of both erosive and osteophytic lesions with 1mm and 1.5 mm in size. However, there were no significant differences between Tomography and Panoramic in correct detection of both erosive and osteophytic lesions with 0.5 mm in size. Conclusions: CBCT images provide a greater diagnostic accuracy than spiral tomography and panoramic radiography in the detection of condylar bone erosions and osteophytes. Key words:Bone defect, Condyle, CBCT, Panoramic, radiography. PMID:25810839

  20. A Preliminary Study of the Burgers Equation with Symbolic Computation

    NASA Astrophysics Data System (ADS)

    Derickson, Russell G.; Pielke, Roger A.

    2000-07-01

    A novel approach based on recursive symbolic computation is introduced for the approximate analytic solution of the Burgers equation. Once obtained, appropriate numerical values can be inserted into the symbolic solution to explore parametric variations. The solution is valid for both inviscid and viscous cases, covering the range of Reynolds number from 500 to infinity, whereas current direct numerical simulation (DNS) methods are limited to Reynolds numbers no greater than 4000. What further distinguishes the symbolic approach from numerical and traditional analytic techniques is the ability to reveal and examine direct nonlinear interactions between waves, including the interplay between inertia and viscosity. Thus, preliminary efforts suggest that symbolic computation may be quite effective in unveiling the “anatomy” of the myriad interactions that underlie turbulent behavior. However, due to the tendency of nonlinear symbolic operations to produce combinatorial explosion, future efforts will require the development of improved filtering processes to select and eliminate computations leading to negligible high order terms. Indeed, the initial symbolic computations present the character of turbulence as a problem in combinatorics. At present, results are limited in time evolution, but reveal the beginnings of the well-known “saw tooth” waveform that occurs in the inviscid case (i.e., Re=∞). Future efforts will explore more fully developed 1-D flows and investigate the potential to extend symbolic computations to 2-D and 3-D. Potential applications include the development of improved subgrid scale (SGS) parameterizations for large eddy simulation (LES) models, and studies that complement DNS in exploring fundamental aspects of turbulent flow behavior.

  1. Modification of ACSYNT aircraft computer program for preliminary design

    NASA Technical Reports Server (NTRS)

    Biezad, Daniel J.; Rojos-Oviedo, Ruben

    1994-01-01

    This paper presents the development of a computer simulation of agility flight test techniques. Its purpose is to evaluate the agility of aircraft configurations early in the preliminary design phase. The simulation module is integrated into the NASA Ames aircraft synthesis design code. Trade studies using the agility module embedded within the design code to simulate the combat cycle time agility metric are illustrated using a Northrop F-20 aircraft model. Results show that the agility module is effective in analyzing the influence of common parameters such as thrust-to-weight ratio and wing loading on agility criteria. The module can also compare the agility potential between different configurations and has the capability to optimize agility performance early in the design process.

  2. Emission Computed Tomography: A New Technique for the Quantitative Physiologic Study of Brain and Heart in Vivo

    DOE R&D Accomplishments Database

    Phelps, M. E.; Hoffman, E. J.; Huang, S. C.; Schelbert, H. R.; Kuhl, D. E.

    1978-01-01

    Emission computed tomography can provide a quantitative in vivo measurement of regional tissue radionuclide tracer concentrations. This facility when combined with physiologic models and radioactively labeled physiologic tracers that behave in a predictable manner allow measurement of a wide variety of physiologic variables. This integrated technique has been referred to as Physiologic Tomography (PT). PT requires labeled compounds which trace physiologic processes in a known and predictable manner, and physiologic models which are appropriately formulated and validated to derive physiologic variables from ECT data. In order to effectively achieve this goal, PT requires an ECT system that is capable of performing truly quantitative or analytical measurements of tissue tracer concentrations and which has been well characterized in terms of spatial resolution, sensitivity and signal to noise ratios in the tomographic image. This paper illustrates the capabilities of emission computed tomography and provides examples of physiologic tomography for the regional measurement of cerebral and myocardial metabolic rate for glucose, regional measurement of cerebral blood volume, gated cardiac blood pools and capillary perfusion in brain and heart. Studies on patients with stroke and myocardial ischemia are also presented.

  3. Differential diagnosis of endodontic-related inferior alveolar nerve paraesthesia with cone beam computed tomography: a case report.

    PubMed

    Gambarini, G; Plotino, G; Grande, N M; Testarelli, L; Prencipe, M; Messineo, D; Fratini, L; D'Ambrosio, F

    2011-02-01

    To discuss the use of cone-beam computed tomography (CBCT) in the differential diagnosis of a case of labiomandibular paraesthesia caused by extrusion of endodontic sealer into the mandibular canal. A 59-year-old woman suffering from a paraesthesia on the left posterior mandible and numbness on the left side of the lower lip was referred to an endodontic specialist 1 month after multiple root canal treatments. A panoramic radiograph revealed the presence of extruded root filling material beyond the apex of the mesial root of the mandibular left second molar and also beyond the apex of the first premolar. A cone beam computed tomography examination was undertaken, which confirmed the presence of radiopaque root canal filling material in the periapical area of the second molar, and revealed that the material was inside the mandibular canal. No extruded filling material was found inside the mental foramen beyond the apex of the first premolar tooth. Small field of view CBCT (where possible) can be considered an effective radiographic diagnostic device when endodontic-related inferior alveolar nerve or mental foramen paraesthesia are suspected. CBCT is able to provide detailed three-dimensional images of the tooth, the root canal system and the surrounding tissue. © 2010 International Endodontic Journal.

  4. Verification of In-Treatment Tumor Position Using Kilovoltage Cone-Beam Computed Tomography: A Preliminary Study

    SciTech Connect

    Nakagawa, Keiichi Yamashita, Hideomi; Shiraishi, Kenshiro; Igaki, Hiroshi; Terahara, Atsuro; Nakamura, Naoki; Ohtomo, Kuni; Saegusa, Shigeki R.T.T.; Shiraki, Takashi R.T.T.; Oritate, Takashi R.T.T.; Yoda, Kiyoshi

    2007-11-15

    Three-dimensional tumor position during rotational dose delivery was evaluated by acquiring in-treatment kilovoltage (kV) cone-beam CT (CBCT) to ensure treatment quality. The CBCT projection data of a phantom were acquired during rotational megavoltage (MV) dose delivery up to 6 Gy to evaluate image quality under MV beam irradiation. A lung tumor patient was treated with a total dose of 48 Gy in four fractions, each fraction including seven coplanar and noncoplanar beams, as well as a full-angle rotational beam. Tumor registration was performed between a planning CT image and a CBCT image immediately after patient setup. The patient couch was adjusted according to the registration results, and then the registration was repeated three times: immediately before treatment, during treatment, and immediately after treatment. The phantom image quality of the kV CBCT was not visually degraded up to the rotational MV dose of 6 Gy. Tumor position during rotational dose delivery was verified for the first time using kV CBCT.

  5. Support vector machine model for diagnosis of lymph node metastasis in gastric cancer with multidetector computed tomography: a preliminary study

    PubMed Central

    2011-01-01

    Background Lymph node metastasis (LNM) of gastric cancer is an important prognostic factor regarding long-term survival. But several imaging techniques which are commonly used in stomach cannot satisfactorily assess the gastric cancer lymph node status. They can not achieve both high sensitivity and specificity. As a kind of machine-learning methods, Support Vector Machine has the potential to solve this complex issue. Methods The institutional review board approved this retrospective study. 175 consecutive patients with gastric cancer who underwent MDCT before surgery were included. We evaluated the tumor and lymph node indicators on CT images including serosal invasion, tumor classification, tumor maximum diameter, number of lymph nodes, maximum lymph node size and lymph nodes station, which reflected the biological behavior of gastric cancer. Univariate analysis was used to analyze the relationship between the six image indicators with LNM. A SVM model was built with these indicators above as input index. The output index was that lymph node metastasis of the patient was positive or negative. It was confirmed by the surgery and histopathology. A standard machine-learning technique called k-fold cross-validation (5-fold in our study) was used to train and test SVM models. We evaluated the diagnostic capability of the SVM models in lymph node metastasis with the receiver operating characteristic (ROC) curves. And the radiologist classified the lymph node metastasis of patients by using maximum lymph node size on CT images as criterion. We compared the areas under ROC curves (AUC) of the radiologist and SVM models. Results In 175 cases, the cases of lymph node metastasis were 134 and 41 cases were not. The six image indicators all had statistically significant differences between the LNM negative and positive groups. The means of the sensitivity, specificity and AUC of SVM models with 5-fold cross-validation were 88.5%, 78.5% and 0.876, respectively. While the diagnostic power of the radiologist classifying lymph node metastasis by maximum lymph node size were only 63.4%, 75.6% and 0.757. Each SVM model of the 5-fold cross-validation performed significantly better than the radiologist. Conclusions Based on biological behavior information of gastric cancer on MDCT images, SVM model can help diagnose the lymph node metastasis preoperatively. PMID:21223564

  6. Bone Mineral Density Estimations From Routine Multidetector Computed Tomography: A Comparative Study of Contrast and Calibration Effects

    PubMed Central

    Kaesmacher, Johannes; Liebl, Hans; Baum, Thomas; Kirschke, Jan Stefan

    2017-01-01

    Introduction Phantom-based (synchronous and asynchronous) and phantomless (internal tissue calibration based) assessment of bone mineral density (BMD) in routine MDCT (multidetector computed tomography) examinations potentially allows for diagnosis of osteoporosis. Although recent studies investigated the effects of contrast-medium application on phantom-calibrated BMD measurements, it remains uncertain to what extent internal tissue-calibrated BMD measurements are also susceptible to contrast-medium associated density variation. The present study is the first to systemically evaluate BMD variations related to contrast application comparing different calibration techniques. Purpose To compare predicative performance of different calibration techniques for BMD measurements obtained from triphasic contrast-enhanced MDCT. Materials and Methods Bone mineral density was measured on nonenhanced (NE), arterial (AR) and portal-venous (PV) contrast phase MDCT images of 46 patients using synchronous (SYNC) and asynchronous (ASYNC) phantom calibration as well as internal calibration (IC). Quantitative computed tomography (QCT) served as criterion standard. Density variations were analyzed for each contrast phase and calibration technique, and respective linear fitting was performed. Results Both asynchronous calibration-derived BMD values (NE-ASYNC) and values estimated using IC (NE-IC) on NE MDCT images did reasonably well in predicting QCT BMD (root-mean-square deviation, 8.0% and 7.8%, respectively). Average NE-IC BMD was 2.7% lower when compared with QCT (P = 0.017), whereas no difference could be found for NE-ASYNC (P = 0.957). All average BMD estimates derived from contrast-enhanced scans differed significantly from QCT BMD (all P < 0.005) and led to notable systemic BMD biases (mean difference at least > 6.0 mg/mL). All regression fits revealed a consistent linear dependency (R2 range, 0.861–0.963). Overall accuracy and goodness of fit tended to decrease from AR to

  7. Glenohumeral joint kinematics measured by intracortical pins, reflective markers, and computed tomography: A novel technique to assess acromiohumeral distance.

    PubMed

    Dal Maso, Fabien; Blache, Yoann; Raison, Maxime; Lundberg, Arne; Begon, Mickaël

    2016-08-01

    Combination of biplane fluoroscopy and CT-scan provides accurate 3D measurement of the acromiohumeral distance (AHD) during dynamic tasks. However, participants performed only two and six trials in previous experiments to respect the recommended radiation exposure per year. Our objective was to propose a technique to assess the AHD in 3D during dynamic tasks without this limitation. The AHD was computed from glenohumeral kinematics obtained using markers fitted to pins drilled into the scapula and the humerus combined with 3D bone geometry obtained using CT-scan. Four participants performed range-of-motion, daily-living, and sports activities. Sixty-six out of 158trials performed by each participant were analyzed. Two participants were not considered due to experimental issues. AHD decreased with arm elevation. Overall, the smallest AHD occurred in abduction (1.1mm (P1) and 1.2mm (P2)). The smallest AHD were 2.4mm (P1) and 3.1mm (P2) during ADL. It was 2.8mm (P1) and 1.1mm (P2) during sports activities. The humeral head greater and lesser tuberosities came the nearest to the acromion. The proposed technique increases the number of trials acquired during one experiment compared to previous. The identification of movements maximizing AHD is possible, which may provide benefits for shoulder rehabilitation.

  8. Evaluation of the rapid and slow maxillary expansion using cone-beam computed tomography: a randomized clinical trial.

    PubMed

    Pereira, Juliana da S; Jacob, Helder B; Locks, Arno; Brunetto, Mauricio; Ribeiro, Gerson L U

    2017-01-01

    The aim of this randomized clinical trial was to evaluate the dental, dentoalveolar, and skeletal changes occurring right after the rapid maxillary expansion (RME) and slow maxillary expansion (SME) treatment using Haas-type expander. All subjects performed cone-beam computed tomography (CBCT) before installation of expanders (T1) and right after screw stabilization (T2). Patients who did not follow the research parameters were excluded. The final sample resulted in 21 patients in RME group (mean age of 8.43 years) and 16 patients in SME group (mean age of 8.70 years). Based on the skewness and kurtosis statistics, the variables were judged to be normally distributed and paired t-test and student t-test were performed at significance level of 5%. Intermolar angle changed significantly due to treatment and RME showed greater buccal tipping than SME. RME showed significant changes in other four measurements due to treatment: maxilla moved forward and mandible showed backward rotation and, at transversal level both skeletal and dentoalveolar showed significant changes due to maxillary expansion. SME showed significant dentoalveolar changes due to maxillary expansion. Only intermolar angle showed significant difference between the two modalities of maxillary expansion with greater buccal tipping for RME. Also, RME produced skeletal maxillary expansion and SME did not. Both maxillary expansion modalities were efficient to promote transversal gain at dentoalveolar level. Sagittal and vertical measurements did not show differences between groups, but RME promoted a forward movement of the maxilla and backward rotation of the mandible.

  9. Evaluation of stability after pre-orthodontic orthognathic surgery using cone-beam computed tomography: A comparison with conventional treatment

    PubMed Central

    Ann, Hye-Rim; Jung, Young-Soo; Lee, Kee-Joon

    2016-01-01

    Objective The aim of this study was to evaluate the skeletal and dental changes after intraoral vertical ramus osteotomy (IVRO) with and without presurgical orthodontics by using cone-beam computed tomography (CBCT). Methods This retrospective cohort study included 24 patients (mean age, 22.1 years) with skeletal Class III malocclusion who underwent bimaxillary surgery with IVRO. The patients were divided into the preorthodontic orthognathic surgery (POGS) group (n = 12) and conventional surgery (CS) group (n = 12). CBCT images acquired preoperatively, 1 month after surgery, and 1 year after surgery were analyzed to compare the intergroup differences in postoperative three-dimensional movements of the maxillary and mandibular landmarks and the changes in lateral cephalometric variables. Results Baseline demographics (sex and age) were similar between the two groups (6 men and 6 women in each group). During the postsurgical period, the POGS group showed more significant upward movement of the mandible (p < 0.05) than did the CS group. Neither group showed significant transverse movement of any of the skeletal landmarks. Moreover, none of the dental and skeletal variables showed significant intergroup differences 1 year after surgery. Conclusions Compared with CS, POGS with IVRO resulted in significantly different postsurgical skeletal movement in the mandible. Although both groups showed similar skeletal and dental outcomes at 1 year after surgery, upward movement of the mandible during the postsurgical period should be considered to ensure a more reliable outcome after POGS. PMID:27668193

  10. Generation of realistic virtual nodules based on three-dimensional spatial resolution in lung computed tomography: A pilot phantom study.

    PubMed

    Narita, Akihiro; Ohkubo, Masaki; Murao, Kohei; Matsumoto, Toru; Wada, Shinichi

    2017-08-04

    The aim of this feasibility study using phantoms was to propose a novel method for obtaining computer-generated realistic virtual nodules in lung computed tomography (CT). In the proposed methodology, pulmonary nodule images obtained with a CT scanner are deconvolved with the point spread function (PSF) in the scan plane and slice sensitivity profile (SSP) measured for the scanner; the resultant images are referred to as nodule-like object functions. Next, by convolving the nodule-like object function with the PSF and SSP of another (target) scanner, the virtual nodule can be generated so that it has the characteristics of the spatial resolution of the target scanner. To validate the methodology, the authors applied physical nodules of 5-, 7- and 10-mm-diameter (uniform spheres) included in a commercial CT test phantom. The nodule-like object functions were calculated from the sphere images obtained with two scanners (Scanner A and Scanner B); these functions were referred to as nodule-like object functions A and B, respectively. From these, virtual nodules were generated based on the spatial resolution of another scanner (Scanner C). By investigating the agreement of the virtual nodules generated from the nodule-like object functions A and B, the equivalence of the nodule-like object functions obtained from different scanners could be assessed. In addition, these virtual nodules were compared with the real (true) sphere images obtained with Scanner C. As a practical validation, five types of laboratory-made physical nodules with various complicated shapes and heterogeneous densities, similar to real lesions, were used. The nodule-like object functions were calculated from the images of these laboratory-made nodules obtained with Scanner A. From them, virtual nodules were generated based on the spatial resolution of Scanner C and compared with the real images of laboratory-made nodules obtained with Scanner C. Good agreement of the virtual nodules generated from

  11. Sensitivity analysis for liver iron measurement through neutron stimulated emission computed tomography: a Monte Carlo study in GEANT4.

    PubMed

    Agasthya, G A; Harrawood, B C; Shah, J P; Kapadia, A J

    2012-01-07

    Neutron stimulated emission computed tomography (NSECT) is being developed as a non-invasive imaging modality to detect and quantify iron overload in the human liver. NSECT uses gamma photons emitted by the inelastic interaction between monochromatic fast neutrons and iron nuclei in the body to detect and quantify the disease. Previous simulated and physical experiments with phantoms have shown that NSECT has the potential to accurately diagnose iron overload with reasonable levels of radiation dose. In this work, we describe the results of a simulation study conducted to determine the sensitivity of the NSECT system for hepatic iron quantification in patients of different sizes. A GEANT4 simulation of the NSECT system was developed with a human liver and two torso sizes corresponding to small and large patients. The iron concentration in the liver ranged between 0.5 and 20 mg g(-1), corresponding to clinically reported iron levels in iron-overloaded patients. High-purity germanium gamma detectors were simulated to detect the emitted gamma spectra, which were background corrected using suitable water phantoms and analyzed to determine the minimum detectable level (MDL) of iron and the sensitivity of the NSECT system. These analyses indicate that for a small patient (torso major axis = 30 cm) the MDL is 0.5 mg g(-1) and sensitivity is ∼13 ± 2 Fe counts/mg/mSv and for a large patient (torso major axis = 40 cm) the values are 1 mg g(-1) and ∼5 ± 1 Fe counts/mg/mSv, respectively. The results demonstrate that the MDL for both patient sizes lies within the clinically significant range for human iron overload.

  12. Cost-effectiveness of screening for lung cancer with low-dose computed tomography: a systematic literature review.

    PubMed

    Puggina, Anna; Broumas, Athanasios; Ricciardi, Walter; Boccia, Stefania

    2016-02-01

    On 31 December 2013, the US Preventive Services Task Force rated low-dose computed tomography (LDCT) for lung cancer screening as level 'B' recommendation. Yet, lung cancer screening implementation remains controversial, particularly when considering its cost-effectiveness. The aim of this work is to investigate the cost-effectiveness of LDCT screening program for lung cancer by performing a systematic literature review. We reviewed the published economic evaluations of LDCT in lung cancer screening. MEDLINE, ISI Web of Science and Cochrane databases were searched for literature retrieval up to 31 March 2015. Inclusion criteria included: studies reporting an original full economic evaluation; reports presenting the outcomes as Quality-Adjusted Life Years (QALYs) gained or as Life Years Gained. Nine economic evaluations met the inclusion criteria. All the cost-effectiveness analyses included high risk populations for lung cancer and compared the use of annual LDCT screening with no screening. Seven studies reported an incremental cost-effectiveness ratio below the threshold of US$ 100 000 per QALY gained. Cost-effectiveness of LDCT screening for lung cancer is an highly debatable issue. Currently available economic evaluations suggest the cost-effectiveness of LDCT for lung cancer screening compared with no screening and indicate that the implementation of LDCT should be considered when planning a national lung cancer screening program. Additional economic evaluations, especially from a societal perspective and in an EU-setting, are needed. © The Author 2015. Published by Oxford University Press on behalf of the European Public Health Association. All rights reserved.

  13. Oral Midazolam-Ketamine versus Midazolam alone for Procedural Sedation of Children Undergoing Computed Tomography; a Randomized Clinical Trial

    PubMed Central

    Majidinejad, Saeed; Taherian, Keramat; Esmailian, Mehrdad; Khazaei, Mehdi; Samaie, Vajihe

    2015-01-01

    Introduction: Motion artifacts are a common problem in pediatric radiographic studies and are a common indication for pediatric procedural sedation. This study aimed to compare the combination of oral midazolam and ketamine (OMK) with oral midazolam alone (OM) as procedural sedatives among children undergoing computed tomography (CT) imaging. Methods: The study population was comprised of six-month to six-year old patients with medium-risk minor head trauma, who were scheduled to undergo brain CT imaging. Patients were randomly allocated to two groups: one group received 0.5 mg/kg midazolam (OM group; n = 33) orally and the other one received 0.2 mg/kg midazolam and 5 mg/kg ketamine orally (OMK group; n=33). The vital signs were monitored and recorded at regular intervals. The primary outcome measure was the success rate of each drug in achieving adequate sedation. Secondary outcome measures were the time to achieve adequate sedation, time to discharge from radiology department, and the incidence of adverse events. Results: Adequate sedation was achieved in five patients (15.2%) in OM group and 15 patients (45.5%) in OMK group, which showed a statistically significant difference between the groups (p = 0.015). No significant difference was noted between OM and OMK groups with respect to the time of achieving adequate sedation (33.80 ± 7.56 and 32.87 ± 10.18 minutes, respectively; p = 0.854) and the time of discharging from radiology department (89.60 ± 30.22 and 105.27 ± 21.98 minutes, respectively; p=0.223). The complications were minor and similar among patients of both groups. Conclusion: This study demonstrated that in comparison with OM, OMK was more effective in producing a satisfactory level of sedation in children undergoing CT examinations without additional complications; however, none of these two regimens fulfilled clinical needs for procedural sedation. PMID:26495384

  14. A meta-analysis: is low-dose computed tomography a superior method for risky lung cancers screening population?

    PubMed

    Fu, Cuiping; Liu, Zilong; Zhu, Fen; Li, Shanqun; Jiang, Liyan

    2016-05-01

    Low-dose computed tomography (LDCT) has been proposed to be a new screening method to discover lung cancers in an early stage, especially those patients who are in a high risk of lung cancer. The primary objective of this meta-analysis is to systematically review the effect of LDCT on screening for lung cancers among the risky population who are older than 49 years old and with smoking exposure. We searched randomized controlled clinical trials (RCTs) about comparing LDCT and chest X-ray or usual caring from MEDLINE, EMBASE, and the Cochrane Library, Web of Knowledge and SpringerLink databases (January 1994 to September 2013). Nine RCTs met criteria for inclusion. Screening for lung cancer using LDCT resulted in a significantly higher number of stage I lung cancers [odds ratio (OR) 2.15, 95% confidence interval (CI) 1.88-2.47], higher number of total lung cancers (OR 1.31, 95% CI 1.20-1.43) than the control. Four of the nine studies indicated that the screening method did not decrease all-cause mortality (OR 0.96, 95% CI 0.90-1.02), but decreased lung cancer-specific mortality (OR 0.84, 95% CI 0.74-0.96). Five studies showed that LDCT had higher false-positive rates (OR 8.7, 95% CI 7.43-10.19) than the group of control. Among the risky population, LDCT screening find out more stage I lung cancers and total lung cancers compared with chest X-ray or no screening, and also shows advantages in decreasing lung cancer-specific mortality, but the screening method does not decrease all-cause mortality and have a higher false-positive rates in diagnosis. © 2014 John Wiley & Sons Ltd.

  15. High-Density Free Fluid on Computed Tomography: a Predictor of Surgical Intervention in Patients with Adhesive Small Bowel Obstruction.

    PubMed

    Matsushima, Kazuhide; Inaba, Kenji; Dollbaum, Ryan; Cheng, Vincent; Khan, Moazzam; Herr, Keith; Strumwasser, Aaron; Asturias, Sabrina; Dilektasli, Evren; Demetriades, Demetrios

    2016-11-01

    Patients with adhesive small bowel obstruction (ASBO) often develop intraabdominal free fluid (IFF). While IFF is a finding on abdominopelvic computed tomography (CT) associated with the need for surgical intervention, many patients with IFF can be still managed non-operatively. A previous study suggested that a higher red blood cell count of IFF is highly predictive of strangulated ASBO. We hypothesized that radiodensity in IFF (Hounsfield unit (HU)) on CT would predict the need for surgical intervention. Patients with clinicoradiological evidence of ASBO between January 2009 and December 2013 were identified. In patients with IFF > 3 cm(2) identified on CT, the HU was measured in the largest pocket of IFF. A sensitivity analysis was performed to determine a high-density HU threshold. The HU of patients who underwent therapeutic laparotomy was compared with those successfully discharged with non-operative management. A total of 318 patients with ASBO (median age 52 years, 56.0 % male) were identified. Of 111 patients who had IFF on CT, 55.9 % underwent therapeutic laparotomy and 15.3 % required bowel resection. Radiodensity of IFF in the operative group was significantly higher than that in the non-operative group (18.2 vs. 7.0 HU, p < 0.01). Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of high-density IFF (>10 HU) to predict the need for surgical intervention were 83.9, 65.3, 75.4, 76.2, and 75.6 %, respectively. High-density IFF on CT was significantly associated with the need for surgical intervention in patients with ASBO. Prospective study to validate the predictive value of high-density IFF on CT will be warranted.

  16. Little impact of tsunami-stricken nuclear accident on awareness of radiation dose of cardiac computed tomography: a questionnaire study.

    PubMed

    Kim, Sung Hea; Kim, Hyun-Joong; Ki, Hyun Kyun; Chung, Eui-Jong; Suh, Soon Yong; Han, Seong Woo; Ryu, Kyu-Hyung

    2013-04-30

    With the increased use of cardiac computed tomography (CT), radiation dose remains a major issue, although physicians are trying to reduce the substantial risks associated with use of this diagnostic tool. This study was performed to investigate recognition of the level of radiation exposure from cardiac CT and the differences in the level of awareness of radiation before and after the Fukushima nuclear plant accident. We asked 30 physicians who were undergoing training in internal medicine to determine the equivalent doses of radiation for common radiological examinations when a normal chest X-ray is accepted as one unit; questions about the absolute radiation dose of cardiac CT data were also asked. According to the results, 86.6% of respondents believed the exposure to be 1 mSv at most, and 93.3% thought that the exposure was less than that of 100 chest X-rays. This finding indicates that their perceptions were far lower than the actual amounts. Even after the occurrence of such a large nuclear disaster in Fukushima, there were no significant differences in the same subjects' overall awareness of radiation amounts. Even after such a major social issue as the Fukushima nuclear accident, the level of awareness of the accurate radiation amount used in 64-channel multidetector CT (MDCT) by clinical physicians who order this test was not satisfactory. Thus, there is a need for the development of effective continuing education programs to improve awareness of radiation from ionizing radiation devices, including cardiac CT, and emphasis on risk-benefit evaluation based on accurate knowledge during medical training.

  17. Evaluation of the rapid and slow maxillary expansion using cone-beam computed tomography: a randomized clinical trial

    PubMed Central

    Pereira, Juliana da S.; Jacob, Helder B.; Locks, Arno; Brunetto, Mauricio; Ribeiro, Gerson L. U.

    2017-01-01

    ABSTRACT OBJECTIVE: The aim of this randomized clinical trial was to evaluate the dental, dentoalveolar, and skeletal changes occurring right after the rapid maxillary expansion (RME) and slow maxillary expansion (SME) treatment using Haas-type expander. METHODS: All subjects performed cone-beam computed tomography (CBCT) before installation of expanders (T1) and right after screw stabilization (T2). Patients who did not follow the research parameters were excluded. The final sample resulted in 21 patients in RME group (mean age of 8.43 years) and 16 patients in SME group (mean age of 8.70 years). Based on the skewness and kurtosis statistics, the variables were judged to be normally distributed and paired t-test and student t-test were performed at significance level of 5%. RESULTS: Intermolar angle changed significantly due to treatment and RME showed greater buccal tipping than SME. RME showed significant changes in other four measurements due to treatment: maxilla moved forward and mandible showed backward rotation and, at transversal level both skeletal and dentoalveolar showed significant changes due to maxillary expansion. SME showed significant dentoalveolar changes due to maxillary expansion. CONCLUSIONS: Only intermolar angle showed significant difference between the two modalities of maxillary expansion with greater buccal tipping for RME. Also, RME produced skeletal maxillary expansion and SME did not. Both maxillary expansion modalities were efficient to promote transversal gain at dentoalveolar level. Sagittal and vertical measurements did not show differences between groups, but RME promoted a forward movement of the maxilla and backward rotation of the mandible. PMID:28658357

  18. How to assess femoral and tibial component rotation after total knee arthroplasty with computed tomography: a systematic review.

    PubMed

    De Valk, Eduard J; Noorduyn, Julia C A; Mutsaerts, Eduard L A R

    2016-11-01

    One of the most important factors leading to revision of total knee arthroplasties (TKA) is malrotation of femoral and/or tibial component. Rotation measurements performed on radiographs are limited and less reliable compared to 2D computed tomography (CT). Nowadays, 2D-CT and 3D-CT can be distinguished in measuring rotation of the TKA components. The aim of this systematic review is to determine the most reliable CT techniques in measuring rotation of the TKA components and to investigate possible cut-off points that can be used in the clinician's decision for a possible revision of the TKA. A search of PubMed, Embase, the Cochrane Central Register of Controlled Trials and Web of Science was performed up to April 2015. Final selections of 12 articles were used in this systematic review. 3D-CT, compared to 2D-CT, is more reliable and shows a high level of intra- and interobserver reliability. Femoral component rotation is measured using the component's posterior condylar line or inner pegs in relation to the epicondylar axis. Five different techniques were used to measure tibial component rotation. The posterior border of the tibial component in relationship to the geometric centre and tibial tubercle was most frequently used. This systematic review shows a strong preference for 3D-CT to determine the component's rotation following a TKA. The literature shows consensus on the reference points of the femoral component. In measurements of the tibial component, various techniques are used with similar results. No clear cut-off point for revision of malrotated TKA components can be stated because of limited evidence. III.

  19. Little impact of tsunami-stricken nuclear accident on awareness of radiation dose of cardiac computed tomography: A questionnaire study

    PubMed Central

    2013-01-01

    Background With the increased use of cardiac computed tomography (CT), radiation dose remains a major issue, although physicians are trying to reduce the substantial risks associated with use of this diagnostic tool. This study was performed to investigate recognition of the level of radiation exposure from cardiac CT and the differences in the level of awareness of radiation before and after the Fukushima nuclear plant accident. Methods We asked 30 physicians who were undergoing training in internal medicine to determine the equivalent doses of radiation for common radiological examinations when a normal chest X-ray is accepted as one unit; questions about the absolute radiation dose of cardiac CT data were also asked. Results According to the results, 86.6% of respondents believed the exposure to be 1 mSv at most, and 93.3% thought that the exposure was less than that of 100 chest X-rays. This finding indicates that their perceptions were far lower than the actual amounts. Even after the occurrence of such a large nuclear disaster in Fukushima, there were no significant differences in the same subjects’ overall awareness of radiation amounts. Conclusions Even after such a major social issue as the Fukushima nuclear accident, the level of awareness of the accurate radiation amount used in 64-channel multidetector CT (MDCT) by clinical physicians who order this test was not satisfactory. Thus, there is a need for the development of effective continuing education programs to improve awareness of radiation from ionizing radiation devices, including cardiac CT, and emphasis on risk-benefit evaluation based on accurate knowledge during medical training. PMID:23631688

  20. Diagnosis of asbestosis by a time expanded wave form analysis, auscultation and high resolution computed tomography: a comparative study.

    PubMed Central

    al Jarad, N; Strickland, B; Bothamley, G; Lock, S; Logan-Sinclair, R; Rudd, R M

    1993-01-01

    BACKGROUND--Crackles are a prominent clinical feature of asbestosis and may be an early sign of the condition. Auscultation, however, is subjective and interexaminer disagreement is a problem. Computerised lung sound analysis can visualise, store, and analyse lung sounds and disagreement on the presence of crackles is minimal. High resolution computed tomography (HRCT) is superior to chest radiography in detecting early signs of asbestosis. The aim of this study was to compare clinical auscultation, time expanded wave form analysis (TEW), chest radiography, and HRCT in detecting signs of asbestosis in asbestos workers. METHODS--Fifty three asbestos workers (51 men and two women) were investigated. Chest radiography and HRCT were assessed by two independent readers for detection of interstitial opacities. HRCT was performed in the supine position with additional sections at the bases in the prone position. Auscultation for persistent fine inspiratory crackles was performed by two independent examiners unacquainted with the diagnosis. TEW analysis was obtained from a 33 second recording of lung sounds over the lung bases. TEW and auscultation were performed in a control group of 13 subjects who had a normal chest radiograph. There were 10 current smokers and three previous smokers. In asbestos workers the extent of pulmonary opacities on the chest radiograph was scored according to the International Labour Office (ILO) scale. Patients were divided into two groups: 21 patients in whom the chest radiograph was > 1/0 (group 1) and 32 patients in whom the chest radiograph was scored < or = 1/0 (group 2) on the ILO scale. RESULTS--In patients with an ILO score of < or = 1/0 repetitive mid to late inspiratory crackles were detected by auscultation in seven (22%) patients and by TEW in 14 (44%). HRCT detected definite interstitial opacities in 11 (34%) and gravity dependent subpleural lines in two (6%) patients. All but two patients with evidence of interstitial disease or

  1. Prediction of presence of kidney disease in patients undergoing intravenous iodinated contrast enhanced computed tomography: a validation study.

    PubMed

    Schreuder, Sanne M; Stoker, Jaap; Bipat, Shandra

    2017-04-01

    To validate two previously presented models containing risk factors to identify patients with estimated glomerular filtration rate (eGFR) <60 ml/min/1.73 m(2) or eGFR <45 ml/min/1.73 m(2). In random patients undergoing intravenous contrast-enhanced computed tomography (CECT) the following risk factors were assessed: history of urological/nephrological disease, hypertension, diabetes mellitus, anaemia, congestive heart failure, other cardiovascular disease or multiple myeloma or Waldenström disease. Data on kidney function, age, gender and type and indication of CECT were also registered. We studied two models: model A-diabetes mellitus, history of urological/nephrological disease, cardiovascular disease, hypertension; model B-diabetes mellitus, history of urological/nephrological disease, age >75 years and congestive heart failure. For each model, associations with eGFR <60 ml/min/1.73 m(2) or eGFR <45 ml/min/1.73 m(2) was studied. A total of 1,001 patients, mean age 60.36 years were included. In total, 92 (9.2 %) patients had an eGFR <60 ml/min/1.73 m(2) and 11 (1.1 %) patients an eGFR <45 ml/min/1.73 m(2). Model A detected 543 patients: 81 with eGFR <60 ml/min/1.73 m(2) (missing 11) and all 11 with eGFR <45 ml/min/1.73 m(2). Model B detected 420 patients: 70 (missing 22) with eGFR <60 ml/min/1.73 m(2) and all 11 with eGFR <45 ml/min/1.73 m(2). Associations were significant (p < 0.05). Model B resulted in the lowest superfluous eGFR measurements while detecting all patients with eGFR <45 ml/min/1.73 m(2) and nearly all with eGFR <60 ml/min/1.73 m(2). • Less than 10% of patients undergoing contrast-enhanced CT have an eGFR of <60ml/min/1.73m (2) • Four risk factors can be used to detect pre-existent kidney disease • It is safe to reduce eGFR measurements using a four-risk-factor model.

  2. Estimation of effective doses to adult and pediatric patients from multislice computed tomography: A method based on energy imparted

    SciTech Connect

    Theocharopoulos, Nicholas; Damilakis, John; Perisinakis, Kostas; Tzedakis, Antonis; Karantanas, Apostolos; Gourtsoyiannis, Nicholas

    2006-10-15

    The purpose of this study is to provide a method and required data for the estimation of effective dose (E) values to adult and pediatric patients from computed tomography (CT) scans of the head, chest abdomen, and pelvis, performed on multi-slice scanners. Mean section radiation dose (d{sub m}) to cylindrical water phantoms of varying radius normalized over CT dose index free-in-air (CTDI{sub F}) were calculated for the head and body scanning modes of a multislice scanner with use of Monte Carlo techniques. Patients were modeled as equivalent water phantoms and the energy imparted ({epsilon}) to simulated pediatric and adult patients was calculated on the basis of measured CTDI{sub F} values. Body region specific energy imparted to effective dose conversion coefficients (E/{epsilon}) for adult male and female patients were generated from previous data. Effective doses to patients aged newborn to adult were derived for all available helical and axial beam collimations, taking into account age specific patient mass and scanning length. Depending on high voltage, body region, and patient sex, E/{epsilon} values ranged from 0.008 mSv/mJ for head scans to 0.024 mSv/mJ for chest scans. When scanned with the same technique factors as the adults, pediatric patients absorb as little as 5% of the energy imparted to adults, but corresponding effective dose values are up to a factor of 1.6 higher. On average, pediatric patients absorb 44% less energy per examination but have a 24% higher effective dose, compared with adults. In clinical practice, effective dose values to pediatric patients are 2.5 to 10 times lower than in adults due to the adaptation of tube current. A method is provided for the calculation of effective dose to adult and pediatric patients on the basis of individual patient characteristics such as sex, mass, dimensions, and density of imaged anatomy, and the technical features of modern multislice scanners. It allows the optimum selection of scanning

  3. Prostate cancer on computed tomography: A direct comparison with multi-parametric magnetic resonance imaging and tissue pathology.

    PubMed

    Jia, Jemianne Bautista; Houshyar, Roozbeh; Verma, Sadhna; Uchio, Edward; Lall, Chandana

    2016-01-01

    Multi-parametric prostate magnetic resonance imaging (MRI) is considered the current imaging standard for detection and staging of prostate cancer. The combination of anatomical and functional imaging provided in this exam significantly increases the accuracy of prostate cancer detection. Computed tomography (CT) imaging has so far been found to be lacking in this regard, however observations at our academic institution as well as evidence present in the literature support the proposition that CT could indeed be helpful in detecting prostate abnormalities that correspond to neoplasm. The purpose of this study was to prove that areas of focal mass-like enhancement on CT imaging directly correlate with prostate neoplasms as revealed on multi-parametric MRI and follow-up targeted biopsy. This was a single institution retrospective study with 27 male subjects. Inclusion criteria required subjects to have a multi-parametric MRI of the prostate between January 1, 2014 and June 1, 2015 and a pelvic venous phase contrast-enhanced CT study between January 1, 2000 and June 1, 2015. Two blinded Radiologists read subjects' CT scans for any abnormalities of the prostate. CT and multi-parametric MRI results were compared and were considered concordant if focal or mass like enhancement to a greater degree than the background parenchyma was detected in the same areas of the prostate on CT scan as areas of decreased T2 signal, perfusion abnormalities, and restricted diffusion on multi-parametric MRI. CT results were directly compared to multi-parametric MRI findings and biopsy results. The overall agreement of MRI and CT is 85.19% (95% CI: 67.52-94.08%). The positive percent agreement is 78.95% (95% CI: 54.43-93.95%) and the negative percent agreement is 100.0% (95% CL: 63.06-100.0%). When CT results are directly compared to biopsy results, sensitivity and specificity of CT are 63.64% (95% CI: 30.79-89.07%) and 100.0% (95% CI: 47.82-100.0%). The positive predictive value (PPV) is

  4. Role of compressive sensing technique in dose reduction for chest computed tomography: a prospective blinded clinical study.

    PubMed

    Khawaja, Ranish Deedar Ali; Singh, Sarabjeet; Lira, Diego; Bippus, Rolf; Do, Synho; Padole, Atul; Pourjabbar, Sarvenaz; Koehler, Thomas; Shepard, Jo-Anne; Kalra, Mannudeep K

    2014-01-01

    The purpose of this study was to assess pulmonary lesion detection, diagnostic confidence, and noise reduction in sparse-sampled (SpS) computed tomographic (CT) data of submillisievert (SubmSv) chest CT reconstructed with iterative reconstruction technique (IRT). This Human Insurance Portability and Accountability-compliant, institutional review board-approved prospective study was performed using SpS-SubmSv IRT chest CT in 10 non-obese patients (body-mass index, 21-35 kg/m; age range, 26-90 years). Written informed consent was obtained. The patients were scanned at standard-dose CT (mean [SD] volumetric CT dose index, 6 [0.9] mGy; mean [SD] dose-length product, 208 ± 44 mGy·cm; and mean [SD] effective dose, 3 [0.6] mSv) and at SubmSv dose (1.8 [0.2] mGy, 67 [2] mGy·cm, 0.9 [0.03] mSv, respectively) on a Philips 128-slice CT scanner with double z-sampling. Sparse angular sampling data were reconstructed using 25% of the angular projections from the SubmSv sinogram to reduce the number of views and radiation dose by approximately 4-fold. Hence, the patients were scanned and then, simulation-based sparse sampling was performed with a resultant dose hypothetical SpS scan estimated mathematically (0.2 mSv). From each patient data, 3 digital imaging and communications in medicine series were generated: SpS-SubmSv with IRT, fully sampled SubmSv filtered back projection (FBP), and fully sampled standard-dose FBP (SD-FBP). Two radiologists independently assessed these image series for detection of lung lesions, visibility of small structures, and diagnostic acceptability. Objective noise was measured in the thoracic aorta, and noise spectral density was obtained for SpS-SubmSv IRT, SubmSv-FBP, and SD-FBP. The SpS-SubmSv IRT resulted in 75% (0.2/0.9 mSv) and 92% (0.2/2.9 mSv) dose reduction, when compared with the fully sampled SubmSv-FBP and SD-FBP, respectively. Images of SpS-SubmSv displayed all 46 lesions (most <1 cm, 30 lung nodules, 7 ground glass opacities, 9

  5. PASS: A computer program for Preliminary Aircraft Structural Synthesis

    NASA Technical Reports Server (NTRS)

    Johnson, E. H.

    1977-01-01

    A computer code for Preliminary Aircraft Structural Synthesis provides rapid and accurate analysis for aircraft structures that can be adequately modeled by beam finite elements. The philosophy used in developing the program was to provide a basic framework that can be used for structural synthesis. It is anticipated that a user will need to add detail to this framework in order to perform his specific task. With this philosophy in mind, the program was written so that it is easily divided into segments, thereby making it readily adaptable. The theoretical portion of this manual describes the basic structure of the program and details the development of the unique beam element that is used. The present capability of the algorithm is stated and suggestions are made regarding enhancements to this capability. User information is also given that provides an overview of the program's construction, identifies the required inputs, describes the program output, provides some comments on the program use, and exhibits results for a simple example.

  6. Perforated duodenal ulcer presenting with a subphrenic abscess revealed by plain abdominal X-ray films and confirmed by multi-detector computed tomography: a case report.

    PubMed

    Camera, Luigi; Calabrese, Milena; Romeo, Valeria; Scordino, Fabrizio; Mainenti, Pier Paolo; Clemente, Marco; Rapicano, Gaetano; Salvatore, Marco

    2013-11-11

    Peptic ulcer disease is still the major cause of gastrointestinal perforation despite major improvements in both diagnostic and therapeutic strategies. While the diagnosis of a perforated ulcer is straightforward in typical cases, its clinical onset may be subtle because of comorbidities and/or concurrent therapies. We report the case of a 53-year-old Caucasian man with a history of chronic myeloid leukemia on maintenance therapy (100mg/day) with imatinib who was found to have a subphrenic abscess resulting from a perforated duodenal ulcer that had been clinically overlooked. Our patient was febrile (38.5°C) with abdominal tenderness and hypoactive bowel sounds. On the abdominal plain X-ray films, a right subphrenic abscess could be seen. On contrast-enhanced multi-detector computed tomography, a huge air-fluid collection extending from the subphrenic to the subhepatic anterior space was observed. After oral administration of 500cm3 of 3 percent diluted diatrizoate meglumine, an extraluminal leakage of the water-soluble iodinated contrast media could then be appreciated as a result of a perforated duodenal ulcer. During surgery, the abscess was drained and extensive adhesiolysis had to be performed to expose the duodenal bulb where the ulcer was first identified by methylene blue administration and then sutured. While subphrenic abscesses are well known complications of perforated gastric or duodenal ulcers, they have nowadays become rare thanks to advances in both diagnostic and therapeutic strategies for peptic ulcer disease. However, when peptic ulcer disease is not clinically suspected, the contribution of imaging may be substantial.

  7. Perforated duodenal ulcer presenting with a subphrenic abscess revealed by plain abdominal X-ray films and confirmed by multi-detector computed tomography: a case report

    PubMed Central

    2013-01-01

    Introduction Peptic ulcer disease is still the major cause of gastrointestinal perforation despite major improvements in both diagnostic and therapeutic strategies. While the diagnosis of a perforated ulcer is straightforward in typical cases, its clinical onset may be subtle because of comorbidities and/or concurrent therapies. Case presentation We report the case of a 53-year-old Caucasian man with a history of chronic myeloid leukemia on maintenance therapy (100mg/day) with imatinib who was found to have a subphrenic abscess resulting from a perforated duodenal ulcer that had been clinically overlooked. Our patient was febrile (38.5°C) with abdominal tenderness and hypoactive bowel sounds. On the abdominal plain X-ray films, a right subphrenic abscess could be seen. On contrast-enhanced multi-detector computed tomography, a huge air-fluid collection extending from the subphrenic to the subhepatic anterior space was observed. After oral administration of 500cm3 of 3 percent diluted diatrizoate meglumine, an extraluminal leakage of the water-soluble iodinated contrast media could then be appreciated as a result of a perforated duodenal ulcer. During surgery, the abscess was drained and extensive adhesiolysis had to be performed to expose the duodenal bulb where the ulcer was first identified by methylene blue administration and then sutured. Conclusions While subphrenic abscesses are well known complications of perforated gastric or duodenal ulcers, they have nowadays become rare thanks to advances in both diagnostic and therapeutic strategies for peptic ulcer disease. However, when peptic ulcer disease is not clinically suspected, the contribution of imaging may be substantial. PMID:24215711

  8. Preliminary performance assessment of computer automated facial approximations using computed tomography scans of living individuals.

    PubMed

    Parks, Connie L; Richard, Adam H; Monson, Keith L

    2013-12-10

    ReFace (Reality Enhancement Facial Approximation by Computational Estimation) is a computer-automated facial approximation application jointly developed by the Federal Bureau of Investigation and GE Global Research. The application derives a statistically based approximation of a face from a unidentified skull using a dataset of ~400 human head computer tomography (CT) scans of living adult American individuals from four ancestry groups: African, Asian, European and Hispanic (self-identified). To date only one unpublished subjective recognition study has been conducted using ReFace approximations. It indicated that approximations produced by ReFace were recognized above chance rates (10%). This preliminary study assesses: (i) the recognizability of five ReFace approximations; (ii) the recognizability of CT-derived skin surface replicas of the same individuals whose skulls were used to create the ReFace approximations; and (iii) the relationship between recognition performance and resemblance ratings of target individuals. All five skin surface replicas were recognized at rates statistically significant above chance (22-50%). Four of five ReFace approximations were recognized above chance (5-18%), although with statistical significance only at the higher rate. Such results suggest reconsideration of the usefulness of the type of output format utilized in this study, particularly in regard to facial approximations employed as a means of identifying unknown individuals.

  9. Feasibility of capillary velocity assessment by statistical means using dual-beam spectral-domain Optical Coherence Tomography: a preliminary study.

    PubMed

    Daly, Susan M; Silien, Christophe; Leahy, Martin J

    2013-09-01

    The assessment of vascular dynamics has been shown to yield both qualitative and quantitative metrics and thus play a pivotal role in the diagnosis and prognosis of various diseases, which may manifest as microcirculatory irregularities. Optical Coherence Tomography (OCT) is an established imaging modality which utilises the principle of optical interferometry to distinguish between spatial changes in refractive index and thus formulate a multi-dimensional representation of a specimen in vivo. Nonetheless, difficulties remain in obtaining accurate data (morphological and/or transient) in an environment which is subject to such large biological variability. In an effort to address the issue of angular dependence as with Doppler based analysis, a dual-beam Spectral-domain OCT system for quasi-simultaneous specimen scanning is described. A statistical based method of phase correlation is outlined which is capable of quantifying velocity values in addition to the ability to discern bidirectionality, without the necessity of angular computation.

  10. Dual-Energy Computed Tomography Angiography of the Head and Neck With Single-Source Computed Tomography: A New Technical (Split Filter) Approach for Bone Removal.

    PubMed

    Kaemmerer, Nadine; Brand, Michael; Hammon, Matthias; May, Matthias; Wuest, Wolfgang; Krauss, Bernhard; Uder, Michael; Lell, Michael M

    2016-10-01

    Dual-energy computed tomographic angiography (DE-CTA) has been demonstrated to improve the visualization of the head and neck vessels. The aim of this study was to test the potential of split-filter single-source dual-energy CT to automatically remove bone from the final CTA data set. Dual-energy CTA was performed in 50 consecutive patients to evaluate the supra-aortic arteries, either to grade carotid artery stenosis or to rule out traumatic dissections. Dual-energy CTA was performed on a 128-slice single-source CT system equipped with a special filter array to separate the 120-kV spectrum into a high- and a low-energy spectrum for DE-based automated bone removal. Image quality of fully automated bone suppression and subsequent manual optimization was evaluated by 2 radiologists on maximum intensity projections using a 4-grade scoring system. The effect of image reconstruction with an iterative metal artifact reduction algorithm on DE postprocessing was tested using a 3-grade scoring system, and the time demand for each postprocessing step was measured. Two patients were excluded due to insufficient arterial contrast enhancement; in the remaining 48 patients, automated bone removal could be performed successfully. The addition of iterative metal artifact reduction algorithm improved image quality in 58.3% of the cases. After manual optimization, DE-CTA image quality was rated excellent in 7, good in 29, and moderate in 10 patients. Interobserver agreement was high (κ = 0.85). Stenosis grading was not influenced using DE-CTA with bone removal as compared with the original CTA. The time demand for DE image reconstruction was significantly higher than for single-energy reconstruction (42.1 vs 20.9 seconds). Our results suggest that bone removal in DE-CTA of the head and neck vessels with a single-source CT is feasible and can be performed within acceptable time and moderate user interaction.

  11. Inter-scan variability of coronary artery calcium scoring assessed on 64-multidetector computed tomography vs. dual-source computed tomography: a head-to-head comparison.

    PubMed

    Ghadri, Jelena R; Goetti, Robert; Fiechter, Michael; Pazhenkottil, Aju P; Küest, Silke M; Nkoulou, Rene N; Windler, Christina; Buechel, Ronny R; Herzog, Bernhard A; Gaemperli, Oliver; Templin, Christian; Kaufmann, Philipp A

    2011-08-01

    Coronary artery calcium (CAC) scoring has emerged as a tool for risk stratification and potentially for monitoring response to risk factor modification. Therefore, repeat measurements should provide robust results and low inter-scanner variability for allowing meaningful comparison. The purpose of this study was to investigate inter-scanner variability of CAC for Agatston, volume, and mass scores by head-to-head comparison using two different cardiac computed tomography scanners: 64-detector multislice CT (MSCT) and 64-slice dual-source CT (DSCT). Thirty patients underwent CAC measurements on both 64-MSCT (GE LightSpeed XT scanner: 120 kV, 70 mAs, 2.5 mm slices) and 64-DSCT (Siemens Somatom Definition: 120 kV, 80 mAs, 3 mm slices) within <100 days (0-97). Retrospective intra-scan comparison revealed an excellent correlation. The excellent intra-scan (inter-observer) agreement was documented by narrow limits of agreement and a correlation coefficient of variation (COV) of r ≥ 0.99 (P < 0.001) for all CAC scores with a low COV for both scanners (64-MSCT/64-DSCT), i.e. Agatston (2.0/2.1%), mass (3.0/2.0%), and volume (4.7/3.9%). Inter-scanner comparison revealed larger Bland-Altman (BA) limits of agreement, despite high correlation (r ≥ 0.97) for all scores, with COV at 15.1, 21.6, and 44.9% for Agatston, mass, and volume scores. The largest BA limits were observed for volume scores (-1552.8 to 574.2), which was massively improved (-241.0 to 300.4, COV 11.5%) after reanalysing the 64-DSCT scans (Siemens) with GE software/workstation (while Siemens software/workstation does not allow cross-vendor analysis). Phantom measurements confirmed overestimation of volume scores by 'syngo Ca-Scoring' (Siemens) software which should therefore be reviewed (vendor has been notified). Intra- and inter-scan agreement of CAC measurement in a given data set is excellent. Inter-scanner variability is reasonable, particularly for Agatston units in the clinically most relevant range

  12. Application of Computational Fluid Dynamics to a Preliminary Extended Area Protection System (EAPS) Projectile

    DTIC Science & Technology

    2006-09-01

    Computational model of a preliminary EAPS projectile configuration. 4 3.2 Computational Mesh The grids for this study were created using GRIDGEN (10), a...Journal 1982, 18 (2), 159–167. 10. Pointwise, Inc. Gridgen Version 15 On-line User’s Manual. Bedford, TX, 2005. 11. Metacomp Technologies. CFD

  13. An integrated computer system for preliminary design of advanced aircraft.

    NASA Technical Reports Server (NTRS)

    Fulton, R. E.; Sobieszczanski, J.; Landrum, E. J.

    1972-01-01

    A progress report is given on the first phase of a research project to develop a system of Integrated Programs for Aerospace-Vehicle Design (IPAD) which is intended to automate to the largest extent possible the preliminary and detailed design of advanced aircraft. The approach used is to build a pilot system and simultaneously to carry out two major contractual studies to define a practical IPAD system preparatory to programing. The paper summarizes the specifications and goals of the IPAD system, the progress to date, and any conclusion reached regarding its feasibility and scope. Sample calculations obtained with the pilot system are given for aircraft preliminary designs optimized with respect to discipline parameters, such as weight or L/D, and these results are compared with designs optimized with respect to overall performance parameters, such as range or payload.

  14. Software Requirements for Embedded Computers: A Preliminary Report.

    DTIC Science & Technology

    1980-03-01

    kinds of problems appeared less frequently in programs that used Phase- O contracts. Although more work is needed before strong recommendations can be...progress of this work, and for suggestions that helped to keep it on track. Finally, thanks are due to Monti Callero and Kenneth Marks, whose reviews...and preliminary software product specifications are also available. RFP to FSD Contract. The initial RFP can be for a Phase- O contract, or for an FSD

  15. Computer-Generated Geometry Instruction: A Preliminary Study

    ERIC Educational Resources Information Center

    Kang, Helen W.; Zentall, Sydney S.

    2011-01-01

    This study hypothesized that increased intensity of graphic information, presented in computer-generated instruction, could be differentially beneficial for students with hyperactivity and inattention by improving their ability to sustain attention and hold information in-mind. To this purpose, 18 2nd-4th grade students, recruited from general…

  16. Computer-Generated Geometry Instruction: A Preliminary Study

    ERIC Educational Resources Information Center

    Kang, Helen W.; Zentall, Sydney S.

    2011-01-01

    This study hypothesized that increased intensity of graphic information, presented in computer-generated instruction, could be differentially beneficial for students with hyperactivity and inattention by improving their ability to sustain attention and hold information in-mind. To this purpose, 18 2nd-4th grade students, recruited from general…

  17. Development of X-TOOLSS: Preliminary Design of Space Systems Using Evolutionary Computation

    NASA Technical Reports Server (NTRS)

    Schnell, Andrew R.; Hull, Patrick V.; Turner, Mike L.; Dozier, Gerry; Alverson, Lauren; Garrett, Aaron; Reneau, Jarred

    2008-01-01

    Evolutionary computational (EC) techniques such as genetic algorithms (GA) have been identified as promising methods to explore the design space of mechanical and electrical systems at the earliest stages of design. In this paper the authors summarize their research in the use of evolutionary computation to develop preliminary designs for various space systems. An evolutionary computational solver developed over the course of the research, X-TOOLSS (Exploration Toolset for the Optimization of Launch and Space Systems) is discussed. With the success of early, low-fidelity example problems, an outline of work involving more computationally complex models is discussed.

  18. Computer-Aided Preliminary Design of Light Antitank Weapons

    DTIC Science & Technology

    1975-07-01

    alogrithm adapted to the computer program CADLAW is the flexible tolerance method originally described by Paviani and Himmelblau [12]. The remaining...Launchers for Vehicles," Frankford Arsenal, Phil- adelphia, Pa., Report No. M66-3-1, August 1965. 12. Paviani, D. and Himmelblau , D. M., Operations...Research, Vol. 17, 1969. 13. Himmelblau , David M., Applied Nonlinear Programming McGraw Hill Book Company, New York, 1972. 14. Lee, Robert F

  19. Computer Assisted Diagnosis of Chest Pain. Preliminary Manual

    DTIC Science & Technology

    1984-04-27

    to date on the computer-based diagnostic program for chest pain. The disorders considered are: myocardial infarction, angina, pneumonia...ANXIOUS (87) DISTRESSED (88) Don’t attempt deep psychoanalysis here. If your patient is obviously reacting to great pain or other severe symptoms...NON-SPECIFIC CHEST PAIN - Non-specific chest pain (NONSCP) is intended to encompass those disorders which are not serious and not a cause for

  20. Analyzing high energy physics data using database computing: Preliminary report

    NASA Technical Reports Server (NTRS)

    Baden, Andrew; Day, Chris; Grossman, Robert; Lifka, Dave; Lusk, Ewing; May, Edward; Price, Larry

    1991-01-01

    A proof of concept system is described for analyzing high energy physics (HEP) data using data base computing. The system is designed to scale up to the size required for HEP experiments at the Superconducting SuperCollider (SSC) lab. These experiments will require collecting and analyzing approximately 10 to 100 million 'events' per year during proton colliding beam collisions. Each 'event' consists of a set of vectors with a total length of approx. one megabyte. This represents an increase of approx. 2 to 3 orders of magnitude in the amount of data accumulated by present HEP experiments. The system is called the HEPDBC System (High Energy Physics Database Computing System). At present, the Mark 0 HEPDBC System is completed, and can produce analysis of HEP experimental data approx. an order of magnitude faster than current production software on data sets of approx. 1 GB. The Mark 1 HEPDBC System is currently undergoing testing and is designed to analyze data sets 10 to 100 times larger.

  1. A preliminary study of molecular dynamics on reconfigurable computers

    SciTech Connect

    Wolinski, C.; Trouw, F. R.; Gokhale, M.

    2003-01-01

    In this paper we investigate the performance of platform FPGAs on a compute-intensive, floating-point-intensive supercomputing application, Molecular Dynamics (MD). MD is a popular simulation technique to track interacting particles through time by integrating their equations of motion. One part of the MD algorithm was implemented using the Fabric Generator (FG)[l I ] and mapped onto several reconfigurable logic arrays. FG is a Java-based toolset that greatly accelerates construction of the fabrics from an abstract technology independent representation. Our experiments used technology-independent IEEE 32-bit floating point operators so that the design could be easily re-targeted. Experiments were performed using both non-pipelined and pipelined floating point modules. We present results for the Altera Excalibur ARM System on a Programmable Chip (SoPC), the Altera Strath EPlS80, and the Xilinx Virtex-N Pro 2VP.50. The best results obtained were 5.69 GFlops at 8OMHz(Altera Strath EPlS80), and 4.47 GFlops at 82 MHz (Xilinx Virtex-II Pro 2VF50). Assuming a lOWpower budget, these results compare very favorably to a 4Gjlop/40Wprocessing/power rate for a modern Pentium, suggesting that reconfigurable logic can achieve high performance at low power on jloating-point-intensivea pplications.

  2. Description and preliminary studies of a computer drawn instrument landing approach display

    NASA Technical Reports Server (NTRS)

    Adams, J. J.; Lallman, F. J.

    1978-01-01

    A computer drawn instrument landing approach display, which shows a box located on the desired path, aligned with the path, and moving along the path at a selected distance ahead of the aircraft, was examined. Vertical and lateral displacements from the desired path and aircraft altitude information are used as inputs to the computer. A preliminary simulation study with pilot subjects has shown that the pilots find the display very easy to use, and they achieved better performance scores with the box display than with a cross pointer instrument landing display.

  3. Preliminary Computational Analysis of the (HIRENASD) Configuration in Preparation for the Aeroelastic Prediction Workshop

    NASA Technical Reports Server (NTRS)

    Chwalowski, Pawel; Florance, Jennifer P.; Heeg, Jennifer; Wieseman, Carol D.; Perry, Boyd P.

    2011-01-01

    This paper presents preliminary computational aeroelastic analysis results generated in preparation for the first Aeroelastic Prediction Workshop (AePW). These results were produced using FUN3D software developed at NASA Langley and are compared against the experimental data generated during the HIgh REynolds Number Aero- Structural Dynamics (HIRENASD) Project. The HIRENASD wind-tunnel model was tested in the European Transonic Windtunnel in 2006 by Aachen University0s Department of Mechanics with funding from the German Research Foundation. The computational effort discussed here was performed (1) to obtain a preliminary assessment of the ability of the FUN3D code to accurately compute physical quantities experimentally measured on the HIRENASD model and (2) to translate the lessons learned from the FUN3D analysis of HIRENASD into a set of initial guidelines for the first AePW, which includes test cases for the HIRENASD model and its experimental data set. This paper compares the computational and experimental results obtained at Mach 0.8 for a Reynolds number of 7 million based on chord, corresponding to the HIRENASD test conditions No. 132 and No. 159. Aerodynamic loads and static aeroelastic displacements are compared at two levels of the grid resolution. Harmonic perturbation numerical results are compared with the experimental data using the magnitude and phase relationship between pressure coefficients and displacement. A dynamic aeroelastic numerical calculation is presented at one wind-tunnel condition in the form of the time history of the generalized displacements. Additional FUN3D validation results are also presented for the AGARD 445.6 wing data set. This wing was tested in the Transonic Dynamics Tunnel and is commonly used in the preliminary benchmarking of computational aeroelastic software.

  4. A preliminary transient-fault experiment on the SIFT computer system

    NASA Technical Reports Server (NTRS)

    Butler, Ricky W.; Elks, Carl R.

    1987-01-01

    This paper presents the results of a preliminary experiment to study the effectiveness of a fault-tolerant system's ability to handle transient faults. The primary goal of the experiment was to develop the techniques to measure the parameters needed for a reliability analysis of the SIFT computer system which includes th effects of transient faults. A key aspect of such an analysis is the determination of the effectiveness of the operating system's ability to discriminate between transient and permanent faults. A detailed description of the preliminary transient fault experiment along with the results from 297 transient fault injections are given. Although not enough data was obtained to draw statistically significant conclusions, the foundation has been laid for a large-scale transient fault experiment.

  5. Preliminary design methods for fiber reinforced composite structures employing a personal computer

    NASA Technical Reports Server (NTRS)

    Eastlake, C. N.

    1986-01-01

    The objective of this project was to develop a user-friendly interactive computer program to be used as an analytical tool by structural designers. Its intent was to do preliminary, approximate stress analysis to help select or verify sizing choices for composite structural members. The approach to the project was to provide a subroutine which uses classical lamination theory to predict an effective elastic modulus for a laminate of arbitrary material and ply orientation. This effective elastic modulus can then be used in a family of other subroutines which employ the familiar basic structural analysis methods for isotropic materials. This method is simple and convenient to use but only approximate, as is appropriate for a preliminary design tool which will be subsequently verified by more sophisticated analysis. Additional subroutines have been provided to calculate laminate coefficient of thermal expansion and to calculate ply-by-ply strains within a laminate.

  6. A rare case of solitary subcutaneous scalp metastasis from follicular thyroid carcinoma revealed with positron emission tomography/computed tomography: a case report and review.

    PubMed

    Sager, Sait; Yilmaz, Sabire; Doner, Rana Kaya; Niyazoglu, Mutlu; Halac, Metin; Kanmaz, Bedii

    2014-01-01

    Differentiated thyroid cancer frequently metastasizes to regional cervical lymph nodes and in advanced cases metastases can be seen in the lungs and skeleton. Metastases to the skin or subcutaneous tissue are rare. Here we present a 49-year-old female patient with solitary scalp metastasis from follicular thyroid carcinoma FTC which was revealed with positron emission tomography (PET)/computed tomography (CT) imaging. PET showed flourodeoxiglucose avid lesion in the left vertex scalp. Scalp lesion was removed totally and histopathological examination revealed well-differentiated thyroid cancer metastasis.

  7. [Development of a computer-assisted system to teach pathologic anatomy. Preliminary results].

    PubMed

    Sobrino, A; Sola, J J; Pardo-Mindán, F J

    1994-04-09

    The present study describes the implantation of an interactive teaching system to improve both the active involvement of the student and the learning quality of Pathology. The preliminary results from the evaluation of such system are also reported. Two attitude questionnaires (rating scale) were passed to a sample of 36 students of Medicine, randomly elected. These students used for 10 weeks a programme of Pathology (Interpat) assisted by computer. Moreover, the data stored after each session by the control stack of this programme are analyzed. The programme is positively evaluated by the users who consider it as an appropriate mode of learning Pathology. In spite of the scarce experience with computers, students have no difficulty in using this programme. 82% of students consider that they learn more Pathology with Interpat than with the traditional system of magistral classes. 63% of students believe that similar systems must be applied in other curricula. The average time of use of the system by each student has been 11 h 45 min (SD 4 h 55 min). The videodisc is the stack more used. There is a good acceptance of this methodology by the students, being almost no difficulty in using the programme, despite their low level of computer knowledge. The program is a potent instrument for individualizing the teaching of Pathology. The small size of the sample, accurate for a preliminary study as this is, must be take into account when generalizing the results.

  8. What is the frequency of anatomical variations and pathological findings in maxillary sinuses among patients subjected to maxillofacial cone beam computed tomography? A systematic review

    PubMed Central

    Diago-Vilalta, Jose-Vicente; Melo, María; Bagán, Leticia; Soldini, Maria-Costanza; Di-Nardo, Chiara; Ata-Ali, Fadi; Mañes-Ferrer, José-Félix

    2017-01-01

    Background When considering dental implant rehabilitation in atrophic posterior sectors, the maxillary sinuses must be evaluated in detail. Knowledge of the anatomical variations and of the potential lesions found in these structures conditions the outcome of sinus lift procedures and therefore of the dental implants. A systematic review is made to determine the frequency of anatomical variations and pathological findings in maxillary sinuses among patients subjected to cone beam computed tomography (CBCT). Material and Methods A PubMed (MEDLINE) literature search was made of articles published up until 20 December 2015. The systematic review was conducted based on the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA). The quality of the studies included in the review was assessed using the Methodological Index for Nonrandomized Studies (MINORS). Results The combinations of search terms resulted in a list of 3482 titles. Twenty-three studies finally met the inclusion criteria and were entered in the systematic review, comprising a total of 11,971 patients. The most common anatomical variations were pneumatization and sinus septa. The prevalence of maxillary sinus disease ranged from 7.5% to 66%. The most common pathological findings of the maxillary sinus were mucosal thickening, sinusitis and sinus opacification. Conclusions Although the main indication of CBCT of the maxillary sinus in dentistry is sinus floor elevation/treatment planning and evaluation prior to dental implant placement, this imaging modality is increasingly also used for endodontic and periodontal purposes. There is no consensus regarding the cutoff point beyond which mucosal thickening of the maxillary sinus should be regarded as pathological, and the definition of maxillary sinusitis moreover varies greatly in the scientific literature. In this regard, international consensus is required in relation to these concepts, with a clear distinction between healthy and

  9. Atypical findings of perineural cysts on postmyelographic computed tomography: a case report of intermittent intercostal neuralgia caused by thoracic perineural cysts.

    PubMed

    Iwamuro, Hirokazu; Yanagawa, Taro; Takamizawa, Sachiko; Taniguchi, Makoto

    2017-06-13

    Perineural cysts are sometimes found incidentally with magnetic resonance imaging, and clinical symptoms requiring treatment are rare. Perineural cysts typically exhibit delayed filling with contrast medium on myelography, which is one of the criteria used by Tarlov to distinguish perineural cysts from meningeal diverticula. We present a case of multiple thoracolumbar perineural cysts, one of which was considered the cause of intermittent intercostal neuralgia with atypical findings on postmyelographic computed tomography seen as selective filling of contrast medium. A 61-year-old woman presented with intermittent pain on her left chest wall with distribution of the pain corresponding to the T10 dermatome. Magnetic resonance imaging showed multiple thoracolumbar perineural cysts with the largest located at the left T10 nerve root. On postmyelographic computed tomography immediately after contrast medium injection, the largest cyst and another at left T9 showed selective filling of contrast medium, suggesting that inflow of cerebrospinal fluid to the cyst exceeded outflow. Three hours after the injection, the intensity of the cysts was similar to the intensity of the thecal sac, and by the next day, contrast enhancement was undetectable. The patient was treated with an intercostal nerve block at T10, and the pain subsided. However, after 9 months of observation, the neuralgia recurred, and the nerve block was repeated with good effect. There was no recurrence 22 months after the last nerve block. We concluded that intermittent elevation of cerebrospinal fluid pressure in the cyst caused the neuralgia because of an imbalance between cerebrospinal fluid inflow and outflow, and repeated intercostal nerve blocks resolved the neuralgia. Our case demonstrates the mechanism of cyst expansion.

  10. Variable uptake feature of focal nodular hyperplasia in Tc-99m phytate hepatic scintigraphy/single-photon emission computed tomography-A parametric analysis.

    PubMed

    Hsu, Yu-Ling; Chen, Yu-Wen; Lin, Chia-Yang; Lai, Yun-Chang; Chen, Shinn-Cherng; Lin, Zu-Yau

    2015-12-01

    Tc-99m phytate hepatic scintigraphy remains the standard method for evaluating the functional features of Kupffer cells. In this study, we demonstrate the variable uptake feature of focal nodular hyperplasia (FNH) in Tc-99m phytate scintigraphy. We reviewed all patients who underwent Tc-99m phytate hepatic scintigraphy between 2008 and 2012 in Kaohsiung Medical University Hospital, Kaohsiung, Taiwan. Cases with FNH were diagnosed on the basis of pathology or at least one or more prior imaging with a periodic clinical follow-up. All patients received a standard protocol of dynamic flow study and planar and Tc-99m phytate single-photon emission computed tomography (E. CAM; Siemens). The correlation of variable nodular radioactivity with parameters such as tumor size and localization was analyzed. In total, 15 lesions of 14 patients in the clinic were diagnosed as FNH. The tumor size was approximately 2.9-7.4 cm (mean size 4.6 cm). Four lesions were larger than 5 cm. The major anatomic distribution was in the right hepatic lobe (10 lesions), particularly in the superior segments (7 lesions). Tc-99m phytate single-photon emission computed tomography imaging for determining the functional features of Kupffer cells included cool/cold (8 lesions), isoradioactive/warm (6 lesions), and hot (1 lesion) patterns of uptake. We did not observe any statistically significant correlation between variable nodular radioactivity and tumor size (p=0.68) or localization (p=0.04). Herein, we demonstrate the variable uptake feature of FNH in Tc-99m phytate scintigraphy. In small FNH tumors (< 5 cm), increased or equal uptake still provided specificity for the differential diagnosis of hepatic solid tumors.

  11. New insight into scar-related ventricular tachycardia circuits in ischemic cardiomyopathy: Fat deposition after myocardial infarction on computed tomography--A pilot study.

    PubMed

    Sasaki, Takeshi; Calkins, Hugh; Miller, Christopher F; Zviman, Menekhem M; Zipunnikov, Vadim; Arai, Tomio; Sawabe, Motoji; Terashima, Masashiro; Marine, Joseph E; Berger, Ronald D; Nazarian, Saman; Zimmerman, Stefan L

    2015-07-01

    Myocardial fat deposition (FAT-DEP) has been frequently observed in regions of chronic myocardial infarction in patients with ischemic cardiomyopathy. The role of FAT-DEP within scar-related ventricular tachycardia (VT) circuits has not been investigated. This pilot study aimed to assess the impact of myocardial FAT-DEP on local electrograms and VT circuits in patients with ischemic cardiomyopathy. Contrast-enhanced computed tomography was performed in 22 patients with ischemic VT. Electroanatomic map points were registered to the corresponding contrast-enhanced computed tomography images. Myocardial FAT-DEP was identified and characterized using a postprocessing image overlay that highlighted areas below 0 Hounsfield units (HU). The mean attenuation of local myocardial regions corresponding to sampled electrograms was measured on short-axis images. The associations of mean attenuation with bipolar and unipolar amplitudes, left ventricular wall thickness, and VT circuit sites were investigated. Of 1801 electroanatomic map points, 519 (28.8%) were located in regions with FAT-DEP. Significant differences were observed in mean intensity (23.2 ± 35.6 HU vs 81.7 ± 21.9 HU; P < .001), bipolar (0.75 ± 0.83 mV vs 2.9 ± 2.4 mV; P < .001) and unipolar (3.1 ± 1.7 mV vs 7.4 ± 4.3 mV; P < .001) amplitudes, and left ventricular wall thickness (5.2 ± 1.7 mm vs 8.2 ± 2.5 mm; P < .001) between regions with and without FAT-DEP. Lower HU was strongly associated with lower bipolar and unipolar amplitudes (P < .0001, respectively). Importantly, FAT-DEP was associated with critical VT circuit sites with fractionated or isolated potentials. FAT-DEP was associated with electrogram characteristics and VT circuit sites. Further work will be needed to determine whether FAT-DEP plays a causal role in the generation of ischemic scar-related VT circuits. Copyright © 2015 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

  12. Comparative evaluation of soft and hard tissue dimensions in the anterior maxilla using radiovisiography and cone beam computed tomography: A pilot study

    PubMed Central

    Mallikarjun, Savita; Babu, Harsha Mysore; Das, Sreedevi; Neelakanti, Abhilash; Dawra, Charu; Shinde, Sachin Vaijnathrao

    2016-01-01

    Aims: To assess and compare the thickness of gingiva in the anterior maxilla using radiovisiography (RVG) and cone beam computed tomography (CBCT) and its correlation with the thickness of underlying alveolar bone. Settings and Design: This cross-sectional study included 10 male subjects in the age group of 20–45 years. Materials and Methods: After analyzing the width of keratinized gingiva of the maxillary right central incisor, the radiographic assessment was done using a modified technique for RVG and CBCT, to measure the thickness of both the labial gingiva and labial plate of alveolar bone at 4 predetermined locations along the length of the root in each case. Statistical Analysis Used: Statistical analysis was performed using Student's t-test and Pearson's correlation test, with the help of statistical software (SPSS V13). Results: No statistically significant differences were obtained in the measurement made using RVG and CBCT. The results of the present study also failed to reveal any significant correlation between the width of gingiva and the alveolar bone in the maxillary anterior region. Conclusions: Within the limitations of this study, it can be concluded that both CBCT and RVG can be used as valuable tools in the assessment of the soft and hard tissue dimensions. PMID:27143830

  13. Radiation doses for pregnant women in the late pregnancy undergoing fetal-computed tomography: a comparison of dosimetry and Monte Carlo simulations.

    PubMed

    Matsunaga, Yuta; Kawaguchi, Ai; Kobayashi, Masanao; Suzuki, Shigetaka; Suzuki, Shoichi; Chida, Koichi

    2016-09-19

    The purposes of this study were (1) to compare the radiation doses for 320- and 80-row fetal-computed tomography (CT), estimated using thermoluminescent dosimeters (TLDs) and the ImPACT Calculator (hereinafter referred to as the "CT dosimetry software"), for a woman in her late pregnancy and her fetus and (2) to estimate the overlapped fetal radiation dose from a 320-row CT examination using two different estimation methods of the CT dosimetry software. The direct TLD data in the present study were obtained from a previous study. The exposure parameters used for TLD measurements were entered into the CT dosimetry software, and the appropriate radiation dose for the pregnant woman and her fetus was estimated. When the whole organs (e.g., the colon, small intestine, and ovaries) and the fetus were included in the scan range, the difference in the estimated doses between the TLD measurement and the CT dosimetry software measurement was <1 mGy (<23 %) in both CT units. In addition, when the whole organs were within the scan range, the CT dosimetry software was used for evaluating the fetal radiation dose and organ-specific doses for the woman in the late pregnancy. The conventional method using the CT dosimetry software cannot take into account the overlap between volumetric sections. Therefore, the conventional method using a 320-row CT unit in a wide-volume mode might result in the underestimation of radiation doses for the fetus and the colon, small intestine, and ovaries.

  14. Fluorodeoxyglucose positron emission tomography-computed tomography: a novel approach for the diagnosis of cholecystitis for equivocal diagnoses after ultrasound imaging.

    PubMed

    Nasseri, Yosef; Ourian, Ariel J; Waxman, Alan; D'Angolo, Alessandro; Thomson, Louise E; Margulies, Daniel R

    2012-10-01

    Although hepatobiliary iminodiacetic acid (HIDA) scan is often used when the diagnosis of cholecystitis remains questionable after ultrasound, it carries a high false-positive rate and has other limitations. Fluorodeoxyglucose positron emission tomography-computed tomography (18FDG PET-CT) has recently gained enthusiasm for its ability to detect infection and inflammation. In this study, we evaluate the accuracy of 18FDG PET-CT in diagnosing cholecystitis. Nineteen patients with suspected cholecystitis (Group S) underwent PET-CT and 10 had positive PET-CT findings. Of these 10, nine underwent cholecystectomies, and pathology confirmed cholecystitis in all nine. One patient was managed nonoperatively as a result of multiple comorbidities. Of the nine patients with negative PET-CT, six were managed nonoperatively, safely discharged, and had no readmissions at 3-month follow-up. The other three patients with negative PET-CT underwent cholecystectomies, and two showed no cholecystitis on pathology. The third had mild to moderate cholecystitis with focal mucosal erosion/ulceration without gallbladder wall thickening on pathology. 18FDG PET-CT detected gallbladder inflammation in all but one patient with pathology-proven cholecystitis with a sensitivity and specificity of 0.90 and 1.00, respectively. 18FDG-PET-CT appears to be a promising, rapid, direct, and accurate test in diagnosing cholecystitis and could replace HIDA scan in cases that remain equivocal after ultrasound.

  15. INCIDENTAL AND NONINCIDENTAL CANINE THYROID TUMORS ASSESSED BY MULTIDETECTOR ROW COMPUTED TOMOGRAPHY: A SINGLE-CENTRE CROSS SECTIONAL STUDY IN 4520 DOGS.

    PubMed

    Bertolini, Giovanna; Drigo, Michele; Angeloni, Luca; Caldin, Marco

    2017-02-09

    Thyroid nodules are common in dogs and are increasingly likely to be detected with the increased use of advanced imaging modalities. An unsuspected, nonpalpable, asymptomatic lesion, defined as a thyroid incidentaloma, may be discovered on an imaging study unrelated to the thyroid gland. The objective of this single-center cross-sectional study was to assess the prevalence and computed tomography (CT) characteristics of incidental and nonincidental thyroid tumors in a large population of dogs, using prospective recruitment of patients undergoing CT examination for various reasons during the period of 2005-2015. Unilateral or bilateral thyroid masses were detected in 96/4520 dogs (prevalence, 2.12%; 95% confidence interval [CI], 1.70-2.54%). Seventy-nine (82.3%) lesions were malignant and 17 (17.7%) were benign. Masses were discovered incidentally in 34/96 dogs (overall prevalence of incidentaloma, 0.76%; 95% CI, 0.51-1.02), and 24 (70.6%) of these 34 masses were thyroid carcinomas. Among the CT variables assessed, mineralization, vascular invasion, and tissue invasion were detected only in malignant tumors. Intratumoral vascularization was significantly associated with the presence of thyroid malignancy (P < 0.001). Although incidental thyroid nodules in dogs are relatively rare, they are often malignant. Findings indicated that the neck should be thoroughly assessed in middle-aged and old patients undergoing body CT for various reasons. Thyroid nodules detected incidentally on CT should be sampled to avoid missing thyroid cancer.

  16. Micro- and nano-X-ray computed-tomography: A step forward in the characterization of the pore network of a leached cement paste

    SciTech Connect

    Bossa, Nathan; Chaurand, Perrine; Vicente, Jérôme; Borschneck, Daniel; Levard, Clément; Aguerre-Chariol, Olivier; Rose, Jérôme

    2015-01-15

    Pore structure of leached cement pastes (w/c = 0.5) was studied for the first time from micro-scale down to the nano-scale by combining micro- and nano-X-ray computed tomography (micro- and nano-CT). This allowed assessing the 3D heterogeneity of the pore network along the cement profile (from the core to the altered layer) of almost the entire range of cement pore size, i.e. from capillary to gel pores. We successfully quantified an increase of porosity in the altered layer at both resolutions. Porosity is increasing from 1.8 to 6.1% and from 18 to 58% at the micro-(voxel = 1.81 μm) and nano-scale (voxel = 63.5 nm) respectively. The combination of both CT allowed to circumvent weaknesses inherent of both investigation scales. In addition the connectivity and the channel size of the pore network were also evaluated to obtain a complete 3D pore network characterization at both scales.

  17. Quantitative and qualitative comparison of standard-dose and low-dose pediatric head computed tomography: a retrospective study assessing the effect of adaptive statistical iterative reconstruction.

    PubMed

    Kilic, Koray; Erbas, Gonca; Guryildirim, Melike; Konus, Oznur Leman; Arac, Mehmet; Ilgit, Erhan; Isik, Sedat

    2013-01-01

    Our aim was to assess the effect of adaptive statistical iterative reconstruction (ASIR) on pediatric head computed tomography (CT) examinations. We retrospectively reviewed 305 pediatric head CT examinations. The study population consisted of standard dose (STD, n = 152) examinations reconstructed with filtered back projection and low dose (LD, n = 153) examinations reconstructed with 30% (LD30) and 0% (LD0) ASIR. We compared groups by means of radiation dose, noise measures, and visual grading. Student t test, 1-way analysis of variance test, and Mann-Whitney U test were used for statistical analysis. The dose in the LD30 group was significantly lower (29%) than that in the STD group (P < 0.001). The noise in the white matter (P < 0.001), SNR (P < 0.001), and subjective image noise (P = 0.044) was significantly better in the STD group than those in the LD30 group. There was no significant difference between LD30 and STD groups in the sharpness (P = 0.141), diagnostic acceptability (P = 0.079), and artifacts (P = 0.750) and contrast-to-noise ratio (P = 0.718). In conclusion, we found that a blend of 30% ASIR in a 16-slice multidetector CT produces diagnostically acceptable pediatric head CT examinations with a 29% less dose.

  18. Validation of the Australian diagnostic reference levels for paediatric multi detector computed tomography: a comparison of RANZCR QUDI data and subsequent NDRLS data from 2012 to 2015.

    PubMed

    Anna, Hayton; Wallace, Anthony; Thomas, Peter

    2017-03-01

    The national diagnostic reference level service (NDRLS), was launched in 2011, however no paediatric data were submitted during the first calendar year of operation. As such, Australian national diagnostic reference levels (DRLs), for paediatric multi detector computed tomography (MDCT), were established using data obtained from a Royal Australian and New Zealand College of Radiologists (RANZCR), Quality Use of Diagnostic Imaging (QUDI), study. Paediatric data were submitted to the NDRLS in 2012 through 2015. An analysis has been made of the NDRLS paediatric data using the same method as was used to analyse the QUDI data to establish the Australian national paediatric DRLs for MDCT. An analysis of the paediatric NDRLS data has also been made using the method used to calculate the Australian national adult DRLs for MDCT. A comparison between the QUDI data and subsequent NDRLS data shows the NDRLS data to be lower on average for the Head and AbdoPelvis protocol and similar for the chest protocol. Using an average of NDRLS data submitted between 2012 and 2015 implications for updated paediatric DRLS are considered.

  19. Three-dimensional demonstration of the lymphatic system in the lower extremities with multi-detector-row computed tomography: a study in a cadaver model.

    PubMed

    Yamazaki, Shun; Suami, Hiroo; Imanishi, Nobuaki; Aiso, Sadakazu; Yamada, Minoru; Jinzaki, Masahiro; Kuribayashi, Sachio; Chang, David W; Kishi, Kazuo

    2013-03-01

    Sentinel lymph node biopsy (SLNB) has had a great impact on the staging and treatment of cancer. The purpose of this study was to study the lymphatic anatomy of the lower extremities by constructing three-dimensional images using multi-detector-row computed tomography (MDCT). To select appropriate contrast media for MDCT lymphatic imaging in a cadaver, we tested four kinds of contrast media by injecting them into fresh swine kidneys. After the suitable contrast medium was selected, 10 lower extremities from 5 fresh cadavers were studied. After injection of the contrast medium, each lower extremity was scanned with high-spatial-resolution MDCT. The zinc oxide mixture was found to be the most appropriate contrast formula for MDCT imaging of cadaver lymphatics in terms of CT value and no extravasation. The high-resolution MDCT imaging revealed two different superficial lymphatic pathways in the legs. One lymphatic pathway accompanying the great saphenous vein had a constant course and was connected to the superficial inguinal lymph nodes. However, another pathway, along the small saphenous vein, was variable. Some of the deep lymphatic vessels bypassed the inguinal lymph nodes. Using a new protocol, we were able to construct three-dimensional images of the lower extremity lymphatics in a cadaver model. MDCT imaging provided novel information about two different superficial lymphatic pathways in the lower extremities. Copyright © 2013 Wiley Periodicals, Inc.

  20. Anatomic symmetry of root and root canal morphology of posterior teeth in Indian subpopulation using cone beam computed tomography: A retrospective study.

    PubMed

    Felsypremila, Gnanasekaran; Vinothkumar, Thilla Sekar; Kandaswamy, Deivanayagam

    2015-01-01

    To investigate the anatomic symmetry of maxillary and mandibular posteriors in Indian subpopulation using cone beam computed tomography (CBCT). CBCT images of 246 patients that had at least one noncarious, posterior tooth free of restorations in each quadrant were enrolled for retrospective analysis. A total of 3015 teeth (811 maxillary premolars, 845 mandibular premolars, 738 maxillary molars, and 621 mandibular molars) were analyzed for number of roots and root canals, canal morphology and anatomic symmetry, and concurrent types between the maxilla and mandible. There was no difference in the percentage of symmetry for maxillary first (81.5%) and second (81.5%) premolars. Mandibular second premolars (98.3%) exhibited greater symmetry than mandibular first premolars (96.1%). First molars (77.5% and 82.1%) showed greater symmetry than second molars (70.8% and 78.6%), in both maxillary and mandibular arches, respectively. The most common anatomy observed were: maxillary first premolars - 2 roots with 2 canals, maxillary second premolars - 1 root with 2 canals, mandibular first and second premolars - 1 root with 1 canal, maxillary first and second molars - 3 roots with 4 canals, and mandibular first and second molars - 2 roots with 3 canals. When compared with any other teeth, maximum asymmetry was observed in maxillary second molar (29.2%). The percentage of symmetry observed in the present study varied from 70% to 98% with least percentage of symmetry in maxillary second molars. These data should alert the clinicians while treating homonymous teeth of the same patient.

  1. Non-invasive Assessment of Lower Limb Geometry and Strength Using Hip Structural Analysis and Peripheral Quantitative Computed Tomography: A Population-Based Comparison.

    PubMed

    Litwic, A E; Clynes, M; Denison, H J; Jameson, K A; Edwards, M H; Sayer, A A; Taylor, P; Cooper, C; Dennison, E M

    2016-02-01

    Hip fracture is the most significant complication of osteoporosis in terms of mortality, long-term disability and decreased quality of life. In the recent years, different techniques have been developed to assess lower limb strength and ultimately fracture risk. Here we examine relationships between two measures of lower limb bone geometry and strength; proximal femoral geometry and tibial peripheral quantitative computed tomography. We studied a sample of 431 women and 488 men aged in the range 59-71 years. The hip structural analysis (HSA) programme was employed to measure the structural geometry of the left hip for each DXA scan obtained using a Hologic QDR 4500 instrument while pQCT measurements of the tibia were obtained using a Stratec 2000 instrument in the same population. We observed strong sex differences in proximal femoral geometry at the narrow neck, intertrochanteric and femoral shaft regions. There were significant (p < 0.001) associations between pQCT-derived measures of bone geometry (tibial width; endocortical diameter and cortical thickness) and bone strength (strength strain index) with each corresponding HSA variable (all p < 0.001) in both men and women. These results demonstrate strong correlations between two different methods of assessment of lower limb bone strength: HSA and pQCT. Validation in prospective cohorts to study associations of each with incident fracture is now indicated.

  2. Detection and characterization of crystal suspensions using single-source dual-energy computed tomography: a phantom model of crystal arthropathies.

    PubMed

    Diekhoff, Torsten; Kiefer, Tobias; Stroux, Andrea; Pilhofer, Irid; Juran, Ralf; Mews, Jürgen; Blobel, Jörg; Tsuyuki, Masaharu; Ackermann, Beate; Hamm, Bernd; Hermann, Kay-Geert A

    2015-04-01

    The aim of this study was to perform phantom measurements to prove the feasibility of single-source dual-energy computed tomography (DECT) of the extremities using a volume scan mode. In addition, we, for the first time, wanted to determine which concentrations of monosodium urate (MSU) in gout and calcium pyrophosphate (CP) in pseudogout are needed to detect or distinguish these soft tissue depositions with DECT. We created a hand-shaped plastic phantom assembled with a descending order of concentrations of MSU (6.25%-50%) and CP (1.56%-50%) with similar attenuation in conventional computed tomographic (CT) images. Dual-energy imaging was done on a standard 320-row CT scanner with acquisition of 2 volumes: one at 80 and the other at 135 kV. Using linear regression analysis, dual-energy gradients were calculated for MSU and CP. Thereafter, we selected a specific region of interest on the dual-energy graph to color-code MSU and CP on the images. Three blinded readers scored 10 scans of the randomly equipped phantom, corresponding to 60 samples, to determine the sensitivity and specificity of this technique. Receiver operating characteristics analysis was done to determine the diagnostic power. We found a dual-energy gradient for MSU of 1.020 ± 0.006 and for CP of 0.673 ± 0.001. Assessment of the randomized phantom scans indicates reliable detection of MSU at concentrations of 12.5 % or higher and that of CP at 6.25 % or higher, corresponding to deposits with mean Hounsfield unit values of 59.8 for MSU and 101.1 for CP. The sensitivity for MSU ranged from 83.3% to 97.3% at 15/90 mA (135/80 kV) and from 86.7% to 97.3% at 100/570 mA. Specificity was 96.7% to 100% in 15/90 mA and 100% in 100/570 mA of scans. However, there was inferior sensitivity for CP owing to lower concentrations. In the receiver operating characteristics analysis, the area under the curve for MSU ranged from 0.867 to 0.947 at 15/90 mA and from 0.867 to 0.919 at 100/570 mA and that for CP from 0

  3. EFFECTS OF X-RAY BEAM ANGLE AND GEOMETRIC DISTORTION ON WIDTH OF EQUINE THORACOLUMBAR INTERSPINOUS SPACES USING RADIOGRAPHY AND COMPUTED TOMOGRAPHY-A CADAVERIC STUDY.

    PubMed

    Djernaes, Julie D; Nielsen, Jon V; Berg, Lise C

    2017-03-01

    The widths of spaces between the thoracolumbar processi spinosi (interspinous spaces) are frequently assessed using radiography in sports horses; however effects of varying X-ray beam angles and geometric distortion have not been previously described. The aim of this prospective, observational study was to determine whether X-ray beam angle has an effect on apparent widths of interspinous spaces. Thoracolumbar spine specimens were collected from six equine cadavers and left-right lateral radiographs and sagittal and dorsal reconstructed computed tomographic (CT) images were acquired. Sequential radiographs were acquired with each interspinous space in focus. Measurements were performed for each interspinous space in the focus position and up to eight angled positions as the interspinous space moved away from focus (±). Focus position measurements were compared to matching sagittal CT measurements. Effect of geometric distortion was evaluated by comparing the interspinous space in radiographs with sagittal and dorsal reconstructed CT images. A total of 49 interspinous spaces were sampled, yielding 274 measurements. X-ray beam angle significantly affected measured width of interspinous spaces in position +3 (P = 0.038). Changes in width did not follow a consistent pattern. Interspinous space widths in focus position were significantly smaller in radiographs compared to matching reconstructed CT images for backs diagnosed with kissing spine syndrome (P < 0.001). Geometric distortion markedly affected appearance of interspinous space width between planes. In conclusion, X-ray beam angle and geometric distortion influence radiographically measured widths of interspinous spaces in the equine thoracolumbar spine, and this should be taken into consideration when evaluating sport horses. © 2016 American College of Veterinary Radiology.

  4. Analysis of C-shaped canal systems in mandibular second molars using surgical operating microscope and cone beam computed tomography: A clinical approach

    PubMed Central

    Chhabra, Sanjay; Yadav, Seema; Talwar, Sangeeta

    2014-01-01

    Aims: The study was aimed to acquire better understanding of C-shaped canal systems in mandibular second molar teeth through a clinical approach using sophisticated techniques such as surgical operating microscope and cone beam computed tomography (CBCT). Materials and Methods: A total of 42 extracted mandibular second molar teeth with fused roots and longitudinal grooves were collected randomly from native Indian population. Pulp chamber floors of all specimens were examined under surgical operating microscope and classified into four types (Min's method). Subsequently, samples were subjected to CBCT scan after insertion of K-files size #10 or 15 into each canal orifice and evaluated using the cross-sectional and 3-dimensional images in consultation with dental radiologist so as to obtain more accurate results. Minimum distance between the external root surface on the groove and initial file placed in the canal was also measured at different levels and statistically analyzed. Results: Out of 42 teeth, maximum number of samples (15) belonged to Type-II category. A total of 100 files were inserted in 86 orifices of various types of specimens. Evaluation of the CBCT scan images of the teeth revealed that a total of 21 canals were missing completely or partially at different levels. The mean values for the minimum thickness were highest at coronal followed by middle and apical third levels in all the categories. Lowest values were obtained for teeth with Type-III category at all three levels. Conclusions: The present study revealed anatomical variations of C-shaped canal system in mandibular second molars. The prognosis of such complex canal anatomies can be improved by simultaneous employment of modern techniques such as surgical operating microscope and CBCT. PMID:24944447

  5. IMPROVING CONSPICUITY OF THE CANINE GASTROINTESTINAL WALL USING DUAL PHASE CONTRAST-ENHANCED COMPUTED TOMOGRAPHY: A RETROSPECTIVE CROSS-SECTIONAL STUDY.

    PubMed

    Fitzgerald, Ella; Lam, Richard; Drees, Randi

    2017-03-01

    Gastrointestinal (GI) disease is a common clinical complaint in small animal patients; computed tomography (CT) examinations enable a global overview of the GI tract and associated structures. Previously, the GI wall has been reportedly identified from serosa to mucosa in 77% of standard postcontrast CT studies and wall layers seen in ultrasound have not been distinguished. Inconsistent strong contrast enhancement of the inner layer of the GI mucosal surface was noted on dual phase CT studies acquired in our institution, which increased the visibility of the GI tract and disease processes. The aim of this retrospective, observational, cross-sectional study was to determine the optimal portal vein attenuation for maximizing GI wall conspicuity using dual phase contrast-enhanced CT. Patients with abdominal CT for a non-GI related disease were included. In a pilot study, 175 GI segments from 35 CT studies were graded for presence of mucosal surface enhancement (MSE). The strongest mucosal surface enhancement grade correlated with portal vein attenuation of 43-150 HU; this value was used as inclusion criterion in the main study. A total of 441 GI segments were evaluated in 42 CT studies postcontrast for GI wall conspicuity. The GI wall was conspicuous in 56.7% precontrast, 84.5% at 30s, and 77.3% late postcontrast; 4.7% of segments were removed due to motion blur. At 30 s distinct mucosal surface enhancement was seen in the small intestine and gastric mucosal surface enhancement was poor. Findings supported the use of dual phase contrast-enhanced CT for improving conspicuity of the GI wall. © 2017 American College of Veterinary Radiology.

  6. Distal radius plate of CFR-PEEK has minimal effect compared to titanium plates on bone parameters in high-resolution peripheral quantitative computed tomography: a pilot study.

    PubMed

    de Jong, Joost J A; Lataster, Arno; van Rietbergen, Bert; Arts, Jacobus J; Geusens, Piet P; van den Bergh, Joop P W; Willems, Paul C

    2017-02-27

    Carbon-fiber-reinforced poly-ether-ether-ketone (CFR-PEEK) has superior radiolucency compared to other orthopedic implant materials, e.g. titanium or stainless steel, thus allowing metal-artifact-free postoperative monitoring by computed tomography (CT). Recently, high-resolution peripheral quantitative CT (HRpQCT) proved to be a promising technique to monitor the recovery of volumetric bone mineral density (vBMD), micro-architecture and biomechanical parameters in stable conservatively treated distal radius fractures. When using HRpQCT to monitor unstable distal radius fractures that require volar distal radius plating for fixation, radiolucent CFR-PEEK plates may be a better alternative to currently used titanium plates to allow for reliable assessment. In this pilot study, we assessed the effect of a volar distal radius plate made from CFR-PEEK on bone parameters obtained from HRpQCT in comparison to two titanium plates. Plates were instrumented in separate cadaveric human fore-arms (n = 3). After instrumentation and after removal of the plates duplicate HRpQCT scans were made of the region covered by the plate. HRpQCT images were visually checked for artifacts. vBMD, micro-architectural and biomechanical parameters were calculated, and compared between the uninstrumented and instrumented radii. No visible image artifacts were observed in the CFR-PEEK plate instrumented radius, and errors in bone parameters ranged from -3.2 to 2.6%. In the radii instrumented with the titanium plates, severe image artifacts were observed and errors in bone parameters ranged between -30.2 and 67.0%. We recommend using CFR-PEEK plates in longitudinal in vivo studies that monitor the healing process of unstable distal radius fractures treated operatively by plating or bone graft ingrowth.

  7. Normal limits for left ventricular ejection fraction and volumes determined by gated single photon emission computed tomography--a comparison between two quantification methods.

    PubMed

    Lomsky, Milan; Johansson, Lena; Gjertsson, Peter; Björk, Jonas; Edenbrandt, Lars

    2008-05-01

    To compare gender-related normal limits for left ventricular (LV) ejection fraction (EF), end-diastolic and end-systolic volumes (EDV and ESV), obtained using two myocardial perfusion-gated single photon emission computed tomography (SPECT) quantification methods. A total of 185 patients were retrospectively selected from a consecutive series of patients examined for coronary artery disease (CAD) or for management of known CAD. Patients were included in the study group if they had normal or probably normal results with stress and rest perfusion imaging and if the combined interpretation of perfusion studies and gated rest studies showed no signs or suspicion of myocardial infarction. The gated SPECT studies were performed using a 2-day stress/gated rest Tc-99m sestamibi protocol. All patient studies were processed using CAFU and quantitative-gated SPECT (QGS), the two software packages for quantification of gated SPECT images. The lower normal limits for EF were higher for CAFU compared with QGS for both women (59% versus 53%) and men (54% versus 47%). The upper normal limits for EDV were also higher for CAFU compared with QGS for both women (133 versus 107 ml) and men (182 versus 161 ml). The differences between the software packages were small for ESV (women 44 versus 44 ml; men 69 versus 74 ml). Gender-specific normal limits need to be applied for LV EF and volumes determined by gated SPECT. Separate criteria for abnormal LV EF and EDV need to be used for women and men depending on the software package used.

  8. Assessment of left ventricular volumes, ejection fraction and regional wall motion with retrospective electrocardiogram triggered 320-detector computed tomography: a comparison with 2D-echocardiography.

    PubMed

    Nasis, Arthur; Moir, Stuart; Seneviratne, Sujith K; Cameron, James D; Mottram, Philip M

    2012-04-01

    Left ventricular (LV) volumes, ejection fraction (LVEF) and regional wall motion (LVRWM) have important treatment and prognostic implications in patients with coronary artery disease. We sought to determine the accuracy of 320-row multidetector computed tomography (MDCT) for the assessment of LV volumes, LVEF and LVRWM, using 2D-echocardiography as the reference standard. We evaluated 50 consecutive patients (mean age 60 ± 14 years, 66% male) who underwent 320-detector MDCT (dose-modulated retrospective electrocardiogram-triggering) and 2D-echocardiography within 14 days for investigation of known or suspected coronary artery disease. Two blinded readers measured LV volumes on MDCT and visually assessed LVRWM with a 3-point scale using a 17-segment model. A separate experienced echocardiologist, blinded to MDCT findings, assessed LVRWM on 2D-echocardiograms and determined LV volumes and LVEF using Simpson's biplane method. 2D-echocardiography served as the reference standard. Mean LVEF was 59 ± 9% (range 26-75%) on 2D-echocardiography and 60 ± 9% (range 27-76%) on MDCT. Using linear regression analysis, MDCT agreed very well with 2D-echocardiography for assessment of LVEDV (r(2) = 0.88; P < 0.001), LVESV (r(2) = 0.95; P < 0.001) and LVEF (r(2) = 0.90; P < 0.001). Mean differences (±standard deviation) of 14 ± 13 ml, 5 ± 7 ml and 1 ± 3% were observed between MDCT and 2D-echocardiography for LVEDV, LVESV and LVEF, respectively. On 2D-echocardiography, 81/850 (9.5%) segments had abnormal LVRWM. Agreement for assessment of LVRWM between 2D-echocardiography and MDCT was excellent (96%, k = 0.76). Accurate assessment of LV volumes, LVEF and LVRWM is feasible with 320-detector MDCT, with MDCT demonstrating slightly larger LV volumes than 2D-echocardiography.

  9. A pilot study evaluating shaved cavity margins with micro-computed tomography: a novel method for predicting lumpectomy margin status intraoperatively.

    PubMed

    Tang, Rong; Coopey, Suzanne B; Buckley, Julliette M; Aftreth, Owen P; Fernandez, Leopoldo J; Brachtel, Elena F; Michaelson, James S; Gadd, Michele A; Specht, Michelle C; Koerner, Frederick C; Smith, Barbara L

    2013-01-01

    Microscopically clear lumpectomy margins are essential in breast conservation, as involved margins increase local recurrence. Currently, 18-50% of lumpectomies have close or positive margins that require re-excision. We assessed the ability of micro-computed tomography (micro-CT) to evaluate lumpectomy shaved cavity margins (SCM) intraoperatively to determine if this technology could rapidly identify margin involvement by tumor and reduce re-excision rates. Twenty-five SCM from six lumpectomies were evaluated with a Skyscan 1173 table top micro-CT scanner (Skyscan, Belgium). Micro-CT results were compared to histopathological results. We scanned three SCM at once with a 7-minute scanning protocol, and studied a total of 25 SCM from six lumpectomies. Images of the SCM were evaluated for radiographic signs of breast cancer including clustered microcalcifications and spiculated masses. SCM were negative by micro-CT in 19/25 (76%) and negative (≥2 mm) by histopathology in 19/25 (76%). Margin status by micro-CT was concordant with histopathology in 23/25 (92%). Micro-CT overestimated margin involvement in 1/25 and underestimated margin involvement in 1/25. Micro-CT had an 83.3% positive predictive value, a 94.7% negative predictive value, 83.3% sensitivity, and 94.7% specificity for evaluation of SCM. Evaluation of SCM by micro-CT is an accurate and promising method of intraoperative margin assessment in breast cancer patients. The scanning time required is short enough to permit real-time feedback to the operating surgeon, allowing immediate directed re-excision.

  10. Quantitative assessment of the latarjet procedure for large glenoid defects by computed tomography: a coracoid graft can sufficiently restore the glenoid arc.

    PubMed

    Moon, Seong Cheol; Cho, Nam Su; Rhee, Yong Girl

    2015-05-01

    Coracoid transfer to a large glenoid defect is considered an excellent method to restore the surface area of the anteroinferior glenoid. However, there is little quantitative evidence supporting whether a coracoid graft can sufficiently restore the glenoid arc. To assess whether the Latarjet procedure can sufficiently restore the surface area of the glenoid. Case series; Level of evidence, 4. A total of 44 patients who underwent a Latarjet operation for a large glenoid defect between February 2009 and July 2011 were enrolled in this study. Three-dimensional computed tomography was used to calculate the surface areas of the preoperative glenoid defect size and the reconstructed glenoid. Preoperative and postoperative clinical results also were assessed. At the last follow-up, the mean visual analog scale score for instability during motion improved significantly from 5.1 points (range, 3-10 points) preoperatively to 1.3 points (range, 0-4 points) (P<.001). The mean deficit in external rotation at the side, external rotation at 90° of abduction, and internal rotation to the posterior were 10°±20°, 7°±16°, and 1.9°±4°, respectively (P=.004, .022, and .009, respectively). The overall recurrence rate was 4.5% (2 of 44 shoulders). The mean preoperative glenoid defect size was 157±38 mm2 (range, 141-239 mm2; 25.3%±6% of the intact glenoid surface). The mean surface area of the coracoid graft used for reconstruction was 152±34 mm2 (range, 146-236 mm2; 24.8%±5% of the intact glenoid surface). After the Latarjet procedure, the mean surface area of the reconstructed glenoid was 706±32 mm2 (range, 639-749 mm2). Finally, postoperative glenoid defect size was 5±11 mm2 (range, 3-28 mm2; 1.5%±2% of the intact glenoid surface). The Latarjet procedure can provide satisfactory outcomes, including a low recurrence rate and reliable functional recovery. Defects at the anteroinferior glenoid were restored to nearly normal after coracoid transfer by use of the Latarjet

  11. Is computed tomography a necessary part of a metastatic evaluation for castration-resistant prostate cancer? Results from the Shared Equal Access Regional Cancer Hospital Database.

    PubMed

    Hanyok, Brian T; Howard, Lauren E; Amling, Christopher L; Aronson, William J; Cooperberg, Matthew R; Kane, Christopher J; Terris, Martha K; Posadas, Edwin M; Freedland, Stephen J

    2016-01-15

    Metastatic lesions in prostate cancer beyond the bone have prognostic importance and affect clinical therapeutic decisions. Few data exist regarding the prevalence of soft-tissue metastases at the initial diagnosis of metastatic castration-resistant prostate cancer (mCRPC). This study analyzed 232 men with nonmetastatic (M0) castration-resistant prostate cancer (CRPC) who developed metastases detected by a bone scan or computed tomography (CT). All bone scans and CT scans within the 30 days before or after the mCRPC diagnosis were reviewed. The rate of soft-tissue metastases among those undergoing CT was determined. Then, predictors of soft-tissue metastases and visceral and lymph node metastases were identified. Compared with men undergoing CT (n = 118), men undergoing only bone scans (n = 114) were more likely to have received primary treatment (P = .048), were older (P = .013), and less recently developed metastases (P = .018). Among those undergoing CT, 52 (44%) had soft-tissue metastases, including 20 visceral metastases (17%) and 41 lymph node metastases (35%), whereas 30% had no bone involvement. In a univariable analysis, only prostate-specific antigen (PSA) predicted soft-tissue metastases (odds ratio [OR], 1.27; P = .047), and no statistically significant predictors of visceral metastases were found. A higher PSA level was associated with an increased risk of lymph node metastases (OR, 1.38; P = .014), whereas receiving primary treatment was associated with decreased risk (OR, 0.36; P = .015). The data suggest that there is a relatively high rate of soft-tissue metastasis (44%) among CRPC patients undergoing CT at the initial diagnosis of metastases, including some men with no bone involvement. Therefore, forgoing CT during a metastatic evaluation may lead to an underdiagnosis of soft-tissue metastases and an underdiagnosis of metastases in general. Cancer 2015. © 2015 American Cancer Society. Cancer 2016;122:222-229.

  12. New Insight into Scar-related Ventricular Tachycardia Circuits in Ischemic Cardiomyopathy: Fat Deposition after Myocardial Infarction on Computed Tomography: A Pilot Study

    PubMed Central

    Sasaki, Takeshi; Calkins, Hugh; Miller, Christopher F.; Zviman, Menekhem M.; Zipunnikov, Vadim; Arai, Tomio; Sawabe, Motoji; Terashima, Masashiro; Marine, Joseph E.; Berger, Ronald D.; Nazarian, Saman; Zimmerman, Stefan L.

    2015-01-01

    Background Myocardial fat deposition (FAT-DEP) has been frequently observed in regions of chronic myocardial infarction in patients with ischemic cardiomyopathy (ICM). The role of FAT-DEP within scar-related ventricular tachycardia (VT) circuits has not been investigated. Objective This pilot study aimed to assess the impact of myocardial FAT-DEP on local electrograms and VT circuits in patients with ICM. Methods Contrast-enhanced computed tomography (CE-CT) was performed in 22 patients with ischemic VT. Electroanatomic map (EAM) points were registered to corresponding CE-CT images. Myocardial FAT-DEP were identified and characterized using a post-processing image overlay that highlighted areas below 0 Hounsfield units (HU). The mean attenuation of local myocardial regions corresponding to sampled electrograms was measured on short axis images. The associations of mean attenuation with bipolar and unipolar amplitudes, left ventricular (LV) wall thickness and VT circuit sites were investigated. Results Of 1801 EAM points, 519 (28.8%) were located in regions with FAT-DEP. Significant differences were observed in mean intensity (23.2±35.6 vs. 81.7±21.9 HU, P<0.001), bipolar (0.75±0.83 vs 2.9±2.4 mV, P<0.001) and unipolar (3.1±1.7 vs. 7.4±4.3 mV, P<0.001) amplitudes and LV wall thickness (5.2±1.7 vs. 8.2±2.5 mm, P<0.001) between regions with and without FAT-DEP. Lower HU was strongly associated with lower bipolar and unipolar amplitude (P<0.0001, respectively). Importantly, FAT-DEP was associated with critical VT circuit sites with fractionated or isolated potentials. Conclusions FAT-DEP was associated with electrogram features and VT circuit sites. Further work will be needed to determine whether FAT-DEP plays a causal role in the generation of ischemic scar-related VT circuits. PMID:25814415

  13. Effects of Document Holder on Postural Neck Muscles Activity among Computer Users: A Preliminary Study.

    PubMed

    Ambusam, Subramaniam; Omar, Baharudin; Joseph, Leonard; Deepashini, Harithasan

    2015-01-01

    Computer users are exposed to work related neck disorders due to repetitive movement and static posture for prolonged period. Viewing document and typing simultaneously are one of the contributing factors for neck disorders. This preliminary study was conducted to evaluate the effects of the document holder on the postural neck muscles activity among computer users. Nine healthy participants with pre-defined inclusion and exclusion criteria were recruited for the study. Neck muscles activity were analyzed using the surface electromyography (EMG) in five different document location such as flat right, flat left, flat center, stand right and stand left during a 5 min typing task. The mean and standard deviation results showed a least amount of muscles activity using a document holder compared to without document holder. Nevertheless, the statistical analysis showed no significant differences between the using of a document holder. The effects of document holder on head excursion and neck muscle activity is recommended in clinical neck pain population.

  14. The Square Kilometre Array Science Data Processor. Preliminary compute platform design

    NASA Astrophysics Data System (ADS)

    Broekema, P. C.; van Nieuwpoort, R. V.; Bal, H. E.

    2015-07-01

    The Square Kilometre Array is a next-generation radio-telescope, to be built in South Africa and Western Australia. It is currently in its detailed design phase, with procurement and construction scheduled to start in 2017. The SKA Science Data Processor is the high-performance computing element of the instrument, responsible for producing science-ready data. This is a major IT project, with the Science Data Processor expected to challenge the computing state-of-the art even in 2020. In this paper we introduce the preliminary Science Data Processor design and the principles that guide the design process, as well as the constraints to the design. We introduce a highly scalable and flexible system architecture capable of handling the SDP workload.

  15. In vivo bioprinting for computer- and robotic-assisted medical intervention: preliminary study in mice.

    PubMed

    Keriquel, Virginie; Guillemot, Fabien; Arnault, Isabelle; Guillotin, Bertrand; Miraux, Sylvain; Amédée, Joëlle; Fricain, Jean-Christophe; Catros, Sylvain

    2010-03-01

    We present the first attempt to apply bioprinting technologies in the perspective of computer-assisted medical interventions. A workstation dedicated to high-throughput biological laser printing has been designed. Nano-hydroxyapatite (n-HA) was printed in the mouse calvaria defect model in vivo. Critical size bone defects were performed in OF-1 male mice calvaria with a 4 mm diameter trephine. Prior to laser printing experiments, the absence of inflammation due to laser irradiation onto mice dura mater was shown by means of magnetic resonance imaging. Procedures for in vivo bioprinting and results obtained using decalcified sections and x-ray microtomography are discussed. Although heterogeneous, these preliminary results demonstrate that in vivo bioprinting is possible. Bioprinting may prove to be helpful in the future for medical robotics and computer-assisted medical interventions.

  16. Computer-based cognitive intervention for dementia: preliminary results of a randomized clinical trial.

    PubMed

    Galante, E; Venturini, G; Fiaccadori, C

    2007-01-01

    Dementia is a highly invalidating condition and, given the progressive aging of the population, one of the major issues that health systems will have to face in future years. Recently there has been an increase in the potential of diagnostic tools and pharmacological treatments for dementia; moreover, considerable interest has been expressed regarding non pharmacological interventions. However, the current evidence in support of non pharmacological treatments in patients affected by dementia still does not allow to draw definitive conclusions on what is the most effective treatment to apply, largely because of methodological difficulties and limitations of the studies so far carried out due to the complex nature of the disease. To address this need, we carried out a single blind randomized controlled study on the efficacy of computer cognitive rehabilitation in patients with mild cognitive decline. We here present preliminary data on 11 patients with diagnosis of Alzheimer's Disease (AD) and mild cognitive decline randomly assigned to treatment (a) or control (b) condition (i.e. specific vs. aspecific treatment). The specific treatment (a) consisted in a cycle of 12 individual sessions of computer exercises, while the control condition (b) consisted in sessions of semi-structured interviews with patients, conducted with the same frequency and time period as (a). Cognitive, behavioural and functional assessment was performed by an expert evaluator, blinded to the patients' group allocation. Preliminary results show a significant performance decline only in the control group at the 9-month follow-up compared to both baseline and the 3-month follow-up. Our results suggest that computer based cognitive training in patients with AD and mild cognitive decline is effective at least in delaying the continuous progression of cognitive impairment in AD.

  17. On the computation of preliminary orbits for Earth satellites with radar observations

    NASA Astrophysics Data System (ADS)

    Gronchi, G. F.; Dimare, L.; Bracali Cioci, D.; Ma, H.

    2015-08-01

    We introduce a new method to perform preliminary orbit determination for satellites on low Earth orbits (LEO). This method works with tracks of radar observations: each track is composed by n ≥ 4 topocentric position vectors per pass of the satellite, taken at very short time intervals. We assume very accurate values for the range ρ, while the angular positions (i.e. the line of sight, given by the pointing of the antenna) are less accurate. We wish to correct the errors in the angular positions already in the computation of a preliminary orbit. With the information contained in a pair of radar tracks, using the laws of the two-body dynamics, we can write eight equations in eight unknowns. The unknowns are the components of the topocentric velocity orthogonal to the line of sight at the two mean epochs of the tracks, and the corrections Δ to be applied to the angular positions. We take advantage of the fact that the components of Δ are typically small. We show the results of some tests, performed with simulated observations, and compare this method with Gibbs' and the Keplerian integrals methods.

  18. Preliminary efficacy of a computer-delivered HIV prevention intervention for African American teenage females.

    PubMed

    Klein, Charles H; Card, Josefina J

    2011-12-01

    This study translated SiHLE (Sisters Informing, Healing, Living, and Empowering), a 12-hour Centers for Disease Control and Prevention evidence-based group-level intervention for African American females 14-18 years of age, into a 2-hour computer-delivered individual-level intervention. A randomized controlled trial (n = 178) was conducted to examine the efficacy of the new Multimedia SiHLE intervention. Average condom-protected sex acts (proportion of vaginal sex acts with condoms, last 90 days) for sexually active participants receiving Multimedia SiHLE rose from M = 51% at baseline to M = 71% at 3-month follow-up (t = 2.06, p = .05); no statistically significant difference was found in the control group. Non-sexually active intervention group participants reported a significant increase in condom self-efficacy (t = 2.36, p = .02); no statistically significant difference was found in the control group. The study provides preliminary support for the efficacy of a computer-delivered adaptation of a proven HIV prevention program for African American teenage women. This is consistent with meta-analyses that have shown that computer-delivered interventions, which can often be disseminated at lower per-capita cost than human-delivered interventions, can influence HIV risk behaviors in positive fashion.

  19. Computer-assisted intraosseous anaesthesia for molar and incisor hypomineralisation teeth. A preliminary study.

    PubMed

    Cabasse, C; Marie-Cousin, A; Huet, A; Sixou, J L

    2015-03-01

    Anesthetizing MIH (Molar and Incisor Hypomineralisation) teeth is one of the major challenges in paediatric dentistry. Computer-assisted IO injection (CAIO) of 4% articaine with 1:200,000 epinephrine (Alphacaine, Septodont) has been shown to be an efficient way to anesthetize teeth in children. The aim of this study was to assess the efficacy of this method with MIH teeth. This preliminary study was performed using the Quick Sleeper system (Dental Hi Tec, Cholet, France) that allows computer-controlled rotation of the needle to penetrate the bone and computer-controlled injection of the anaesthetic solution. Patients (39) of the department of Paediatric Dentistry were included allowing 46 sessions (including 32 mandibular first permanent molars) to be assessed. CAIO showed efficacy in 93.5% (43/46) of cases. Failures (3) were due to impossibility to reach the spongy bone (1) and to achieve anaesthesia (2). This prospective study confirms that CAIO anaesthesia is a promising method to anesthetize teeth with MIH that could therefore be routinely used by trained practitioners.

  20. Development of an online automatic computed radiography dose data mining program: a preliminary study.

    PubMed

    Ng, Curtise K C; Sun, Zhonghua

    2010-01-01

    Recent studies have reported the computed radiography (CR) dose creep problem and therefore the need to have monitoring processes in place in clinical departments. The objective of this study is to provide a better technological solution to implement a regular CR dose monitoring process. An online automatic CR dose data mining program which can be applied to different systems was developed based on freeware and existing softwares in the Picture Archiving and Communication System (PACS) server. The program was tested with 69 CR images. This preliminary study shows that the program addresses the major weaknesses of some existing studies including involvement of manual procedures in the monitoring process and being only applicable to a single manufacturer's CR images. The proposed method provides an efficient and effective solution to implement a CR dose monitoring program regularly in busy clinical departments to regulate the dose creep problem so as to reinforce the 'As Low As Reasonably Achievable' (ALARA) principle.

  1. Computational analysis and preliminary redesign of the nozzle contour of the Langley hypersonic CF4 tunnel

    NASA Technical Reports Server (NTRS)

    Thompson, R. A.; Sutton, Kenneth

    1987-01-01

    A computational analysis, modification, and preliminary redesign study was performed on the nozzle contour of the Langley Hypersonic CF4 Tunnel. This study showed that the existing nozzle was contoured incorrectly for the design operating condition, and this error was shown to produce the measured disturbances in the exit flow field. A modified contour was designed for the current nozzle downstream of the maximum turning point that would provide a uniform exit flow. New nozzle contours were also designed for an exit Mach number and Reynolds number combination which matches that attainable in the Langley 20-Inch Mach 6 Tunnel. Two nozzle contours were designed: one having the same exit radius but a larger mass flow rate than that of the existing CF4 Tunnel, and the other having the same mass flow rate but a smaller exit radius than that of the existing CF4 Tunnel.

  2. 26 CFR 1.818-4 - Election with respect to life insurance reserves computed on preliminary term basis.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 26 Internal Revenue 8 2011-04-01 2011-04-01 false Election with respect to life insurance reserves... Provisions § 1.818-4 Election with respect to life insurance reserves computed on preliminary term basis. (a) In general. Section 818(c) permits a life insurance company issuing contracts with respect to...

  3. 26 CFR 1.818-4 - Election with respect to life insurance reserves computed on preliminary term basis.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 26 Internal Revenue 8 2013-04-01 2013-04-01 false Election with respect to life insurance reserves... Provisions § 1.818-4 Election with respect to life insurance reserves computed on preliminary term basis. (a) In general. Section 818(c) permits a life insurance company issuing contracts with respect to...

  4. 26 CFR 1.818-4 - Election with respect to life insurance reserves computed on preliminary term basis.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 26 Internal Revenue 8 2014-04-01 2014-04-01 false Election with respect to life insurance reserves... Provisions § 1.818-4 Election with respect to life insurance reserves computed on preliminary term basis. (a) In general. Section 818(c) permits a life insurance company issuing contracts with respect to...

  5. 26 CFR 1.818-4 - Election with respect to life insurance reserves computed on preliminary term basis.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    .... Section 818(c) permits a life insurance company issuing contracts with respect to which the life insurance... section 801 (relating to the definition of a life insurance company). If such an election is made, the... computed on preliminary term basis. If a life insurance company makes an election under section 818(c)...

  6. Computer simulation of low-dose CT with clinical lung image database: a preliminary study

    NASA Astrophysics Data System (ADS)

    Rong, Junyan; Gao, Peng; Liu, Wenlei; Zhang, Yuanke; Liu, Tianshuai; Lu, Hongbing

    2017-03-01

    Large samples of raw low-dose CT (LDCT) projections on lungs are needed for evaluating or designing novel and effective reconstruction algorithms suitable for lung LDCT imaging. However, there exists radiation risk when getting them from clinical CT scanning. To avoid the problem, a new strategy for producing large samples of lung LDCT projections with computer simulations is proposed in this paper. In the simulation, clinical images from the publicly available medical image database-the Lung Image Database Consortium(LIDC) and Image Database Resource Initiative (IDRI) database (LIDC/IDRI) are used as the projected object to form the noise-free sinogram. Then by adding a Poisson distributed quantum noise plus Gaussian distributed electronic noise to the projected transmission data calculated from the noise-free sinogram, different noise levels of LDCT projections are obtained. At last the LDCT projections are used for evaluating two reconstruction strategies. One is the conventional filtered back projection (FBP) algorithm and the other is FBP reconstruction from the filtered sinogram with penalized weighted least square criterion (PWLS-FBP). Images reconstructed with the LDCT simulations have shown that the PWLS-FBP algorithm performs better than the FBP algorithm in reducing streaking artifacts and preserving resolution. Preliminary results indicate that the feasibility of the proposed lung LDCT simulation strategy for helping to determine advanced reconstruction algorithms.

  7. A preliminary study on the short-term efficacy of chairside computer-aided design/computer-assisted manufacturing- generated posterior lithium disilicate crowns.

    PubMed

    Reich, Sven; Fischer, Sören; Sobotta, Bernhard; Klapper, Horst-Uwe; Gozdowski, Stephan

    2010-01-01

    The purpose of this preliminary study was to evaluate the clinical performance of chairside-generated crowns over a preliminary time period of 24 months. Forty-one posterior crowns made of a machinable lithium disilicate ceramic for full-contour crowns were inserted in 34 patients using a chairside computer-aided design/computer-assisted manufacturing technique. The crowns were evaluated at baseline and after 6, 12, and 24 months according to modified United States Public Health Service criteria. After 2 years, all reexamined crowns (n = 39) were in situ; one abutment exhibited secondary caries and two abutments received root canal treatment. Within the limited observation period, the crowns revealed clinically satisfying results.

  8. Computer-aided detection of HER2 amplification status using FISH images: a preliminary study

    NASA Astrophysics Data System (ADS)

    Zheng, Bin; Wang, Xiao-Hui; Surti, Urvashi; Bhargava, Rohit; Gur, David

    2009-02-01

    The amplification status of human epidermal growth factor receptors 2 (HER2) genes is strongly associated with clinical outcome in patients with breast cancer. The American Society of Clinical Oncology Tumor Marker Guidelines Panel has recommended routine testing of HER2 status on all newly diagnosed metastatic breast cancers since 2001. Although fluorescent in situ hybridization (FISH) technology provides superior accuracy as compared with other approaches, current manual FISH analysis methods are somewhat subjective, tedious, and may introduce interreader variability. The goal of this preliminary study is to develop and test a computer-aided detection (CAD) scheme to assess HER2 status using FISH images. Forty FISH images were selected for this study from our genetic laboratory. The CAD scheme first applies an adaptive, iterative threshold method followed by a labeling algorithm to segment cells of possible interest. A set of classification rules is then used to identify analyzable interphase cells and discard nonanalyzable cells due to cell overlapping and/or other image staining debris (or artifacts). The scheme then maps the detected analyzable cells onto two other gray scale images corresponding to the red and green color of the original image followed by application of a raster scan and labeling algorithms to separately detect the HER-2/neu ("red") and CEP17 ("green") FISH signals. A simple distance based criterion is applied to detect and merge split FISH signals within each cell. The CAD scheme computes the ratio between independent "red" and "green" FISH signals of all analyzable cells identified on an image. If the ratio is >= 2.0, the FISH image is assumed to have been acquired from a HER2+ case; otherwise, the FISH image is assumed to have been acquired from HER2- case. When we applied the CAD scheme to the testing dataset, the average computed HER2 amplification ratios were 1.06+/-0.25 and 2.53+/-0.81 for HER2- and HER2+ samples, respectively. The

  9. Psychosocial and Computer-Assisted Intervention for College Students with Autism Spectrum Disorder: Preliminary Support for Feasibility.

    PubMed

    White, Susan W; Richey, John A; Gracanin, Denis; Coffman, Marika; Elias, Rebecca; LaConte, Stephen; Ollendick, Thomas H

    2016-09-01

    The number of young adults with Autism Spectrum Disorders (ASD) enrolled in higher education institutions has steadily increased over the last decade. Despite this, there has been little research on how to most effectively support this growing population. The current study presents data from a pilot trial of two novel intervention programs developed for college students with ASD. In this small randomized controlled trial, college students with ASD (n = 8) were assigned to one of two new programs - either an intervention based on a virtual reality-Brain-Computer Interface for ASD (BCI-ASD) or a psychosocial intervention, the College and Living Success (CLS) program. Preliminary evidence supports the feasibility and acceptability of both programs, although behavioral outcomes were inconsistent across participants and interventions. Results indicate that expanded research on psychosocial and computer-assisted intervention approaches for this population is warranted, given the preliminary support found in this pilot study.

  10. Wolter X-Ray Microscope Computed Tomography Ray-Trace Model with Preliminary Simulation Results

    SciTech Connect

    Jackson, J A

    2006-02-27

    It is proposed to build a Wolter X-ray Microscope Computed Tomography System in order to characterize objects to sub-micrometer resolution. Wolter Optics Systems use hyperbolic, elliptical, and/or parabolic mirrors to reflect x-rays in order to focus or magnify an image. Wolter Optics have been used as telescopes and as microscopes. As microscopes they have been used for a number of purposes such as measuring emission x-rays and x-ray fluoresce of thin biological samples. Standard Computed Tomography (CT) Systems use 2D radiographic images, from a series of rotational angles, acquired by passing x-rays through an object to reconstruct a 3D image of the object. The x-ray paths in a Wolter X-ray Microscope will be considerably different than those of a standard CT system. There is little information about the 2D radiographic images that can be expected from such a system. There are questions about the quality, resolution and focusing range of an image created with such a system. It is not known whether characterization information can be obtained from these images and whether these 2D images can be reconstructed to 3D images of the object. A code has been developed to model the 2D radiographic image created by an object in a Wolter X-ray Microscope. This code simply follows the x-ray through the object and optics. There is no modeling at this point of other effects, such as scattering, reflection losses etc. Any object, of appropriate size, can be used in the model code. A series of simulations using a number of different objects was run to study the effects of the optics. The next step will be to use this model to reconstruct an object from the simulated data. Funding for the project ended before this goal could be accomplished. The following documentation includes: (1) background information on current X-ray imaging systems, (2) background on Wolter Optics, (3) description of the Wolter System being used, (4) purpose, limitations and development of the modeling

  11. Variability of repeated coronary artery calcium scoring and radiation Dose on 64- and 16-slice computed tomography by prospective electrocardiographically-triggered axial and retrospective electrocardiographically-gated spiral computed tomography: a phantom study.

    PubMed

    Horiguchi, Jun; Kiguchi, Masao; Fujioka, Chikako; Arie, Ryuichi; Shen, Yun; Sunasaka, Kenichi; Kitagawa, Toshiro; Yamamoto, Hideya; Ito, Katsuhide

    2008-08-01

    We sought to compare coronary artery calcium (CAC) scores, the variability and radiation doses on 64- and 16-slice computed tomography (CT) scanners by both prospective electrocardiographically (ECG)-triggered and retrospective ECG-gated scans. Coronary artery models (n = 3) with different plaque CT densities (approximately 240 Hounsfield units [HU], approximately 600 HU, and approximately 1000 HU) of four sizes (1, 3, 5, and 10 mm in length) on a cardiac phantom were scanned three times in five heart rate sequences. The tube current-time products were set to almost the same on all four protocols (32.7 mAs for 64-slice prospective and retrospective scans, 33.3 mAs for 16-slice prospective and retrospective scans). Slice thickness was set to 2.5 mm to keep the radiation dose low. Overlapping reconstruction with a 1.25-mm increment was applied on the retrospective ECG-gated scan. The CAC scores were not different between the four protocols (one-factor analysis of variance: Agatston, P = .32; volume, P = .19; and mass, P = .09). Two-factor factorial analysis of variance test revealed that the interscan variability was different between protocols (P < .01) and scoring algorithms (P < .01). The average variability of Agatston/volume/mass scoring and effective doses were as follows: 64-slice prospective scan: 16%/15%/11% and 0.5 mSv; 64-slice retrospective scan: 11%/11%/8% and 3.7 mSv; 16-slice prospective scan: 20%/18%/13% and 0.6 mSv; and 16-slice retrospective scan: 16%/15%/11% and 2.9 to 3.5 mSv (depending on the pitch). Retrospective ECG-gated 64-slice CT showed the lowest variability. Prospective ECG-triggered 64-slice CT, with low radiation dose, shows low variability on CAC scoring comparable to retrospective ECG-gated 16-slice CT.

  12. Computer-assisted learning in anatomy at the international medical school in Debrecen, Hungary: a preliminary report.

    PubMed

    Kish, Gary; Cook, Samuel A; Kis, Gréta

    2013-01-01

    The University of Debrecen's Faculty of Medicine has an international, multilingual student population with anatomy courses taught in English to all but Hungarian students. An elective computer-assisted gross anatomy course, the Computer Human Anatomy (CHA), has been taught in English at the Anatomy Department since 2008. This course focuses on an introduction to anatomical digital images along with clinical cases. This low-budget course has a large visual component using images from magnetic resonance imaging and computer axial tomogram scans, ultrasound clinical studies, and readily available anatomy software that presents topics which run in parallel to the university's core anatomy curriculum. From the combined computer images and CHA lecture information, students are asked to solve computer-based clinical anatomy problems in the CHA computer laboratory. A statistical comparison was undertaken of core anatomy oral examination performances of English program first-year medical students who took the elective CHA course and those who did not in the three academic years 2007-2008, 2008-2009, and 2009-2010. The results of this study indicate that the CHA-enrolled students improved their performance on required anatomy core curriculum oral examinations (P < 0.001), suggesting that computer-assisted learning may play an active role in anatomy curriculum improvement. These preliminary results have prompted ongoing evaluation of what specific aspects of CHA are valuable and which students benefit from computer-assisted learning in a multilingual and diverse cultural environment.

  13. Ten Years toward Equity: Preliminary Results from a Follow-Up Case Study of Academic Computing Culture

    PubMed Central

    Crenshaw, Tanya L.; Chambers, Erin W.; Heeren, Cinda; Metcalf, Heather E.

    2017-01-01

    Just over 10 years ago, we conducted a culture study of the Computer Science Department at the flagship University of Illinois at Urbana-Champaign, one of the top five computing departments in the country. The study found that while the department placed an emphasis on research, it did so in a way that, in conjunction with a lack of communication and transparency, devalued teaching and mentoring, and negatively impacted the professional development, education, and sense of belonging of the students. As one part of a multi-phase case study spanning over a decade, this manuscript presents preliminary findings from our latest work at the university. We detail early comparisons between data gathered at the Department of Computer Science at the University of Illinois at Urbana-Champaign in 2005 and our most recent pilot case study, a follow-up research project completed in 2016. Though we have not yet completed the full data collection, we find it worthwhile to reflect on the pilot case study data we have collected thus far. Our data reveals improvements in the perceptions of undergraduate teaching quality and undergraduate peer mentoring networks. However, we also found evidence of continuing feelings of isolation, incidents of bias, policy opacity, and uneven policy implementation that are areas of concern, particularly with respect to historically underrepresented groups. We discuss these preliminary follow-up findings, offer research and methodological reflections, and share next steps for applied research that aims to create positive cultural change in computing. PMID:28579969

  14. Preliminary validation of a new methodology for estimating dose reduction protocols in neonatal chest computed radiographs

    NASA Astrophysics Data System (ADS)

    Don, Steven; Whiting, Bruce R.; Hildebolt, Charles F.; Sehnert, W. James; Ellinwood, Jacquelyn S.; Töpfer, Karin; Masoumzadeh, Parinaz; Kraus, Richard A.; Kronemer, Keith A.; Herman, Thomas; McAlister, William H.

    2006-03-01

    The risk of radiation exposure is greatest for pediatric patients and, thus, there is a great incentive to reduce the radiation dose used in diagnostic procedures for children to "as low as reasonably achievable" (ALARA). Testing of low-dose protocols presents a dilemma, as it is unethical to repeatedly expose patients to ionizing radiation in order to determine optimum protocols. To overcome this problem, we have developed a computed-radiography (CR) dose-reduction simulation tool that takes existing images and adds synthetic noise to create realistic images that correspond to images generated with lower doses. The objective of our study was to determine the extent to which simulated, low-dose images corresponded with original (non-simulated) low-dose images. To make this determination, we created pneumothoraces of known volumes in five neonate cadavers and obtained images of the neonates at 10 mR, 1 mR and 0.1 mR (as measured at the cassette plate). The 10-mR exposures were considered "relatively-noise-free" images. We used these 10 mR-images and our simulation tool to create simulated 0.1- and 1-mR images. For the simulated and original images, we identified regions of interest (ROI) of the entire chest, free-in-air region, and liver. We compared the means and standard deviations of the ROI grey-scale values of the simulated and original images with paired t tests. We also had observers rate simulated and original images for image quality and for the presence or absence of pneumothoraces. There was no statistically significant difference in grey-scale-value means nor standard deviations between simulated and original entire chest ROI regions. The observer performance suggests that an exposure >=0.2 mR is required to detect the presence or absence of pneumothoraces. These preliminary results indicate that the use of the simulation tool is promising for achieving ALARA exposures in children.

  15. Computer-Based Automation of Discrete Product Manufacture: A preliminary Discussion of Feasibility and Impact

    DTIC Science & Technology

    1974-07-01

    costs . The use of this type of production automation, which we shall call programmable automation, is consid- ered here for all manufacturing ...current manufacturing application .... This has resulted in substantial product cost savings, improvements in weapon systems performance, qual- ity...5 Our preliminary studies indicate potential cost and time savings for the entire discrete- product manufacturing process comparable to those that

  16. Reducing Foreign Language Communication Apprehension with Computer-Mediated Communication: A Preliminary Study

    ERIC Educational Resources Information Center

    Arnold, Nike

    2007-01-01

    Many studies (e.g., [Beauvois, M.H., 1998. "E-talk: Computer-assisted classroom discussion--attitudes and motivation." In: Swaffar, J., Romano, S., Markley, P., Arens, K. (Eds.), "Language learning online: Theory and practice in the ESL and L2 computer classroom." Labyrinth Publications, Austin, TX, pp. 99-120; Bump, J., 1990. "Radical changes in…

  17. Applying Computer Technology to Substance Abuse Prevention Science Results of a Preliminary Examination

    ERIC Educational Resources Information Center

    Marsch, Lisa A.; Bickel, Warren K.; Badger, Gary J.

    2007-01-01

    This manuscript reports on the development and evaluation of a computer-based substance abuse prevention program for middle school-aged adolescents, called "HeadOn: Substance Abuse Prevention for Grades 6-8TM". This self-guided program was designed to deliver effective drug abuse prevention science to youth via computer-based educational…

  18. How Well Can a Computer Program Teach German Culture? Some Preliminary Findings from EthnoDeutsch.

    ERIC Educational Resources Information Center

    Ashby, Wendy; Ostertag, Veronica

    2002-01-01

    Investigates the effectiveness of an interactive, computer-mediated instructional segment designed to educate students about ethnicity in German-speaking countries. Fifty-two intermediate German students worked with computer-mediated segments and rated the segments' effectiveness on a Likert-scale questionnaire. (AS)

  19. Reducing Foreign Language Communication Apprehension with Computer-Mediated Communication: A Preliminary Study

    ERIC Educational Resources Information Center

    Arnold, Nike

    2007-01-01

    Many studies (e.g., [Beauvois, M.H., 1998. "E-talk: Computer-assisted classroom discussion--attitudes and motivation." In: Swaffar, J., Romano, S., Markley, P., Arens, K. (Eds.), "Language learning online: Theory and practice in the ESL and L2 computer classroom." Labyrinth Publications, Austin, TX, pp. 99-120; Bump, J., 1990. "Radical changes in…

  20. Preliminary Computational Fluid Dynamics (CFD) Simulation of EIIB Push Barge in Shallow Water

    NASA Astrophysics Data System (ADS)

    Beneš, Petr; Kollárik, Róbert

    2011-12-01

    This study presents preliminary CFD simulation of EIIb push barge in inland conditions using CFD software Ansys Fluent. The RANSE (Reynolds Averaged Navier-Stokes Equation) methods are used for the viscosity solution of turbulent flow around the ship hull. Different RANSE methods are used for the comparison of their results in ship resistance calculations, for selecting the appropriate and removing inappropriate methods. This study further familiarizes on the creation of geometrical model which considers exact water depth to vessel draft ratio in shallow water conditions, grid generation, setting mathematical model in Fluent and evaluation of the simulations results.

  1. Preliminary study of the use of the STAR-100 computer for transonic flow calculations

    NASA Technical Reports Server (NTRS)

    Keller, J. D.; Jameson, A.

    1977-01-01

    An explicit method for solving the transonic small-disturbance potential equation is presented. This algorithm, which is suitable for the new vector-processor computers such as the CDC STAR-100, is compared to successive line over-relaxation (SLOR) on a simple test problem. The convergence rate of the explicit scheme is slower than that of SLOR, however, the efficiency of the explicit scheme on the STAR-100 computer is sufficient to overcome the slower convergence rate and allow an overall speedup compared to SLOR on the CYBER 175 computer.

  2. Protocol Analysis of Man-Computer Languages: Design and Preliminary Findings

    DTIC Science & Technology

    1975-07-01

    nacaaaarr ""< (dam/fr by Mock number) application -oriented language design, man-computer language design, man-machine communication, message proce»sing...Officer Ittft C - Keyword Language Form I Hi D - Positional Language Form (14 E - English-like Language Form Mi F - Display Handouts...given a population of users and a category of applications as shown below. iiven: Our problem is to find an on-line computer language that will

  3. The difference between playing games with and without the computer: a preliminary view.

    PubMed

    Antonietti, Alessandro; Mellone, Rosa

    2003-03-01

    The authors address the question of whether associations between video games and cognitive and metacognitive variables depend either on the features of the computer or on the content of the game that the computer allows one to play. An experiment to separate these two kinds of effects was carried out by using a traditional version and a computer-supported version of Pegopolis, a solitaire game. The two versions were exactly the same except that they were played by moving pieces either on a real board or on a virtual computer-presented board. The performance levels and strategies followed during the game by the 40 undergraduates who took part in the experiment were not significantly different in the real and virtual conditions. None of the participants transferred playing strategies or practice from one version of the game to the other. Scores were not affected by gender or by the studies pursued by participants, the habit of playing games in the traditional manner or playing video games, or intelligence. Retrospective reports did not support differences in the subjective experience between the two versions. Results showed that video games, when they do not make much use of the computer's special features, produce effects because of the situations they simulate rather than because of features of the computer itself.

  4. Computer-based attention training in the schools for children with attention deficit/hyperactivity disorder: a preliminary trial.

    PubMed

    Steiner, Naomi J; Sheldrick, Radley Christopher; Gotthelf, David; Perrin, Ellen C

    2011-07-01

    Objective. This study examined the efficacy of 2 computer-based training systems to teach children with attention deficit/hyperactivity disorder (ADHD) to attend more effectively. Design/methods. A total of 41 children with ADHD from 2 middle schools were randomly assigned to receive 2 sessions a week at school of either neurofeedback (NF) or attention training through a standard computer format (SCF), either immediately or after a 6-month wait (waitlist control group). Parents, children, and teachers completed questionnaires pre- and postintervention. Results. Primary parents in the NF condition reported significant (P < .05) change on Conners's Rating Scales-Revised (CRS-R) and Behavior Assessment Scales for Children (BASC) subscales; and in the SCF condition, they reported significant (P < .05) change on the CRS-R Inattention scale and ADHD index, the BASC Attention Problems Scale, and on the Behavioral Rating Inventory of Executive Functioning (BRIEF). Conclusion. This randomized control trial provides preliminary evidence of the effectiveness of computer-based interventions for ADHD and supports the feasibility of offering them in a school setting.

  5. Comparison of different methods to compute a preliminary orbit of Space Debris using radar observations

    NASA Astrophysics Data System (ADS)

    Ma, Hélène; Gronchi, Giovanni F.

    2014-07-01

    We advertise a new method of preliminary orbit determination for space debris using radar observations, which we call Infang †. We can perform a linkage of two sets of four observations collected at close times. The context is characterized by the accuracy of the range ρ, whereas the right ascension α and the declination δ are much more inaccurate due to observational errors. This method can correct α, δ, assuming the exact knowledge of the range ρ. Considering no perturbations from the J 2 effect, but including errors in the observations, we can compare the new method, the classical method of Gibbs, and the more recent Keplerian integrals method. The development of Infang is still on-going and will be further improved and tested.

  6. Psychological underpinnings of intrafamilial computer-mediated communication: a preliminary exploration of CMC uptake with parents and siblings.

    PubMed

    Goby, Valerie Priscilla

    2011-06-01

    This preliminary study investigates the uptake of computer-mediated communication (CMC) with parents and siblings, an area on which no research appears to have been conducted. Given the lack of relevant literature, grounded theory methodology was used and online focus group discussions were conducted in an attempt to generate suitable hypotheses for further empirical studies. Codification of the discussion data revealed various categories of meaning, namely: a perceived inappropriateness of CMC with members of family of origin; issues relating to the family generational gap; the nature of the offline sibling/parent relationship; the non-viability of online affordances such as planned self-disclosure, deception, identity construction; and disinhibition in interactions with family-of-origin members. These themes could be molded into hypotheses to assess the psychosocial limitations of CMC and to determine if it can indeed become a ubiquitous alternative to traditional communication modes as some scholars have claimed.

  7. Preliminary Computational Study for Future Tests in the NASA Ames 9 foot' x 7 foot Wind Tunnel

    NASA Technical Reports Server (NTRS)

    Pearl, Jason M.; Carter, Melissa B.; Elmiligui, Alaa A.; WInski, Courtney S.; Nayani, Sudheer N.

    2016-01-01

    The NASA Advanced Air Vehicles Program, Commercial Supersonics Technology Project seeks to advance tools and techniques to make over-land supersonic flight feasible. In this study, preliminary computational results are presented for future tests in the NASA Ames 9 foot x 7 foot supersonic wind tunnel to be conducted in early 2016. Shock-plume interactions and their effect on pressure signature are examined for six model geometries. Near- field pressure signatures are assessed using the CFD code USM3D to model the proposed test geometries in free-air. Additionally, results obtained using the commercial grid generation software Pointwise Reigistered Trademark are compared to results using VGRID, the NASA Langley Research Center in-house mesh generation program.

  8. Producing computer-generated tailored written information for stroke patients and their carers: system development and preliminary evaluation.

    PubMed

    Hoffmann, Tammy; Russell, Trevor; McKenna, Kryss

    2004-11-01

    The aim of this project was to design and evaluate a system that would produce tailored information for stroke patients and their carers, customised according to their informational needs, and facilitate communication between the patient and health professional. A human factors development approach was used to develop a computer system, which dynamically compiles stroke education booklets for patients and carers. Patients and carers are able to select the topics about which they wish to receive information, the amount of information they want, and the font size of the printed booklet. The system is designed so that the health professional interacts with it, thereby providing opportunities for communication between the health professional and patient/carer at a number of points in time. Preliminary evaluation of the system by health professionals, patients and carers was positive. A randomised controlled trial that examines the effect of the system on patient and carer outcomes is underway.

  9. Computer-mediated communication and the Gallaudet University community: a preliminary report.

    PubMed

    Hogg, Nanette M; Lomicky, Carol S; Weiner, Stephen F

    2008-01-01

    The study examined the use of computer-mediated communication (CMC) among individuals involved in a conflict sparked by the appointment of an administrator as president-designate of Gallaudet University in 2006. CMC was defined as forms of communication used for transmitting (sharing) information through networks with digital devices. There were 662 survey respondents. Respondents reported overwhelmingly (98%) that they used CMC to communicate. Students and alumni reported CMC use in larger proportions than any other group. The favorite devices among all respondents were Sidekicks, stationary computers, and laptops. Half of all respondents also reported using some form of video device. Nearly all reported using e-mail; respondents also identified Web surfing, text messaging, and blogging as popular CMC activities. The authors plan another article reporting on computer and electronic technology use as a mechanism connecting collective identity to social movements.

  10. Integrating Computer Algebra Systems in Post-Secondary Mathematics Education: Preliminary Results of a Literature Review

    ERIC Educational Resources Information Center

    Buteau, Chantal; Marshall, Neil; Jarvis, Daniel; Lavicza, Zsolt

    2010-01-01

    We present results of a literature review pilot study (326 papers) regarding the use of Computer Algebra Systems (CAS) in tertiary mathematics education. Several themes that have emerged from the review are discussed: diverse uses of CAS, benefits to student learning, issues of integration and mathematics learning, common and innovative usage of…

  11. Computer-Animated Instruction and Students' Conceptual Change in Electrochemistry: Preliminary Qualitative Analysis

    ERIC Educational Resources Information Center

    Talib, Othman; Matthews, Robert; Secombe, Margaret

    2005-01-01

    This paper discusses the potential of applying computer-animated instruction (CAnI) as an effective conceptual change strategy in teaching electrochemistry in comparison to conventional lecture-based instruction (CLI). The core assumption in this study is that conceptual change in learners is an active, constructive process that is enhanced by the…

  12. Monitor Tone Generates Stress in Computer and VDT Operators: A Preliminary Study.

    ERIC Educational Resources Information Center

    Dow, Caroline; Covert, Douglas C.

    A near-ultrasonic pure tone of 15,570 Herz generated by flyback transformers in computer and video display terminal (VDT) monitors may cause severe non-specific irritation or stress disease in operators. Women hear higher frequency sounds than men and are twice as sensitive to "too loud" noise. Pure tones at high frequencies are more…

  13. Computational implementation of a systems prioritization methodology for the Waste Isolation Pilot Plant: A preliminary example

    SciTech Connect

    Helton, J.C.; Anderson, D.R.; Baker, B.L.

    1996-04-01

    A systems prioritization methodology (SPM) is under development to provide guidance to the US DOE on experimental programs and design modifications to be supported in the development of a successful licensing application for the Waste Isolation Pilot Plant (WIPP) for the geologic disposal of transuranic (TRU) waste. The purpose of the SPM is to determine the probabilities that the implementation of different combinations of experimental programs and design modifications, referred to as activity sets, will lead to compliance. Appropriate tradeoffs between compliance probability, implementation cost and implementation time can then be made in the selection of the activity set to be supported in the development of a licensing application. Descriptions are given for the conceptual structure of the SPM and the manner in which this structure determines the computational implementation of an example SPM application. Due to the sophisticated structure of the SPM and the computational demands of many of its components, the overall computational structure must be organized carefully to provide the compliance probabilities for the large number of activity sets under consideration at an acceptable computational cost. Conceptually, the determination of each compliance probability is equivalent to a large numerical integration problem. 96 refs., 31 figs., 36 tabs.

  14. Effectiveness and Achievement: A Preliminary Comparison of Computer Assisted and Print Drill Performance Levels.

    ERIC Educational Resources Information Center

    Campbell, Donald L.; And Others

    The performance of two groups of 24 third-grade students practicing division problems was used to assess the effect of microcomputer drill programs on learning. An experimental group that used computer drill programs from the Milliken Math Sequences package was compared with a similar group that learned division using the traditional print drill…

  15. Cognitive Styles among Computer Systems Students: Preliminary Findings from New Arrivals to University.

    ERIC Educational Resources Information Center

    Moore, Sarah; O'Maidin, Donncha; McElligot, Annette

    2003-01-01

    Explored the relationship among cognitive style, performance, gender, and communication among computer students. Found a significant relationship between performance and cognitive style; students whose cognitive style scores indicated a preference for analytical thinking had better performance scores when entering college than those with a…

  16. Computer-Mediated Communication and the Gallaudet University Community: A Preliminary Report

    ERIC Educational Resources Information Center

    Hogg, Nanette M.; Lomicky, Carol S.; Weiner, Stephen F.

    2008-01-01

    The study examined the use of computer-mediated communication (CMC) among individuals involved in a conflict sparked by the appointment of an administrator as president-designate of Gallaudet University in 2006. CMC was defined to comprise forms of communication used for transmitting (sharing) information through networks with digital devices.…

  17. The Use of Computers in Folklore and Folk Music: A Preliminary Bibliography.

    ERIC Educational Resources Information Center

    Stein, Evan, Comp.

    This bibliography on the use of the computer in the analysis and classification of folklore and folk music cites 107 titles of journal articles, books, and other publications gathered from worldwide sources. Countries represented include Africa, China, Czechoslovakia, Denmark, England, Finland, France, Germany, Haiti, Holland, Hungary, Indonesia,…

  18. Upgraded Navy Computer-Managed Instruction: Analysis of Requirements for and Preliminary Instructional System Specifications.

    ERIC Educational Resources Information Center

    Van Matre, Nick; Johnson, Kirk

    Because the Navy's computer-managed instruction (CMI) system has experienced problems with prolonged system response times (RT) and excessive downtime (DT), a survey of Naval personnel was conducted to determine current and near-term CMI system instructional requirements. Questionnaires were sent to instructors, training program coordinators,…

  19. Integrating Computer Algebra Systems in Post-Secondary Mathematics Education: Preliminary Results of a Literature Review

    ERIC Educational Resources Information Center

    Buteau, Chantal; Marshall, Neil; Jarvis, Daniel; Lavicza, Zsolt

    2010-01-01

    We present results of a literature review pilot study (326 papers) regarding the use of Computer Algebra Systems (CAS) in tertiary mathematics education. Several themes that have emerged from the review are discussed: diverse uses of CAS, benefits to student learning, issues of integration and mathematics learning, common and innovative usage of…

  20. Monitor Tone Generates Stress in Computer and VDT Operators: A Preliminary Study.

    ERIC Educational Resources Information Center

    Dow, Caroline; Covert, Douglas C.

    A near-ultrasonic pure tone of 15,570 Herz generated by flyback transformers in computer and video display terminal (VDT) monitors may cause severe non-specific irritation or stress disease in operators. Women hear higher frequency sounds than men and are twice as sensitive to "too loud" noise. Pure tones at high frequencies are more…

  1. High-accuracy computation of Delta V magnitude probability densities - Preliminary remarks

    NASA Technical Reports Server (NTRS)

    Chadwick, C.

    1986-01-01

    This paper describes an algorithm for the high accuracy computation of some statistical quantities of the magnitude of a random trajectory correction maneuver (TCM). The trajectory correction velocity increment Delta V is assumed to be a three-component random vector with each component being a normally distributed random scalar having a possibly nonzero mean. Knowledge of the statitiscal properties of the magnitude of a random TCM is important in the planning and execution of maneuver strategies for deep-space missions such as Galileo. The current algorithm involves the numerical integration of a set of differential equations. This approach allows the computation of density functions for specific Delta V magnitude distributions to high accuracy without first having to generate large numbers of random samples. Possible applications of the algorithm to maneuver planning, planetary quarantine evaluation, and guidance success probability calculations are described.

  2. An Interactive Computer Program for the Preliminary Design and Analysis of Marine Reduction Gears.

    DTIC Science & Technology

    1982-03-01

    axis and simple epicyclic reduction gears. It is caD -beo 71J? 1473 too-roos OP, I Nov6$15i ORLE TVNICLASST IFl um u ewd S/01 0102-014- 6601 66CUOIIY...CONCLUSIONS AND RECOMBENDATICNS Computer aided design ( CAD ) is an important and useful tool ’or engineers. As computer technology continues to expand, CAD ...N e E-H4o m H4 4 E-4. Cad 0 0 = *uuu I! 2I4 E-4 0H o( - =C = e4r (n ) T-N f co~~~2 aU OD 0 %D00mmm0 Aw 0 94 71z 00 0 p nc nc 0 C; 4 H 0 2q 0I go 04

  3. High-accuracy computation of Delta V magnitude probability densities - Preliminary remarks

    NASA Technical Reports Server (NTRS)

    Chadwick, C.

    1986-01-01

    This paper describes an algorithm for the high accuracy computation of some statistical quantities of the magnitude of a random trajectory correction maneuver (TCM). The trajectory correction velocity increment Delta V is assumed to be a three-component random vector with each component being a normally distributed random scalar having a possibly nonzero mean. Knowledge of the statitiscal properties of the magnitude of a random TCM is important in the planning and execution of maneuver strategies for deep-space missions such as Galileo. The current algorithm involves the numerical integration of a set of differential equations. This approach allows the computation of density functions for specific Delta V magnitude distributions to high accuracy without first having to generate large numbers of random samples. Possible applications of the algorithm to maneuver planning, planetary quarantine evaluation, and guidance success probability calculations are described.

  4. Computer code for preliminary sizing analysis of axial-flow turbines

    NASA Technical Reports Server (NTRS)

    Glassman, Arthur J.

    1992-01-01

    This mean diameter flow analysis uses a stage average velocity diagram as the basis for the computational efficiency. Input design requirements include power or pressure ratio, flow rate, temperature, pressure, and rotative speed. Turbine designs are generated for any specified number of stages and for any of three types of velocity diagrams (symmetrical, zero exit swirl, or impulse) or for any specified stage swirl split. Exit turning vanes can be included in the design. The program output includes inlet and exit annulus dimensions, exit temperature and pressure, total and static efficiencies, flow angles, and last stage absolute and relative Mach numbers. An analysis is presented along with a description of the computer program input and output with sample cases. The analysis and code presented herein are modifications of those described in NASA-TN-D-6702. These modifications improve modeling rigor and extend code applicability.

  5. Single-photon emission computed tomography in human immunodeficiency virus encephalopathy: A preliminary report

    SciTech Connect

    Masdeu, J.C.; Yudd, A.; Van Heertum, R.L.; Grundman, M.; Hriso, E.; O'Connell, R.A.; Luck, D.; Camli, U.; King, L.N. )

    1991-08-01

    Depression or psychosis in a previously asymptomatic individual infected with the human immunodeficiency virus (HIV) may be psychogenic, related to brain involvement by the HIV or both. Although prognosis and treatment differ depending on etiology, computed tomography (CT) and magnetic resonance imaging (MRI) are usually unrevealing in early HIV encephalopathy and therefore cannot differentiate it from psychogenic conditions. Thirty of 32 patients (94%) with HIV encephalopathy had single-photon emission computed tomography (SPECT) findings that differed from the findings in 15 patients with non-HIV psychoses and 6 controls. SPECT showed multifocal cortical and subcortical areas of hypoperfusion. In 4 cases, cognitive improvement after 6-8 weeks of zidovudine (AZT) therapy was reflected in amelioration of SPECT findings. CT remained unchanged. SPECT may be a useful technique for the evaluation of HIV encephalopathy.

  6. Preliminary assessment of Tongue Drive System in medium term usage for computer access and wheelchair control.

    PubMed

    Yousefi, Behnaz; Huo, Xueliang; Ghovanloo, Maysam

    2011-01-01

    Tongue Drive System (TDS) is a wireless, wearable assistive technology that enables individuals with severe motor impairments access computers, drive wheelchairs, and control their environments using tongue motion. In this paper, we have evaluated the TDS performance as a computer input device using ISO9241-9 standard tasks for pointing and selecting, based on the well known Fitts' Law, and as a powered wheelchair controller through an obstacle course navigation task. Nine able-bodied subjects who already had tongue piercing participated in this trial over 5 sessions during 5 weeks, allowing us to study the TDS learning process and its current limiting factors. Subjects worn tongue rings made of titanium in the form of a barbell with a small rare earth magnetic tracer hermetically sealed inside the upper ball. Comparing the results between 1(st) and 5(th) sessions showed that subjects' performance improved in all the measures through 5 sessions, demonstrating the effects of learning.

  7. Utilization of computers in clinical practice--role of physician networks: preliminary communication.

    PubMed Central

    Anderson, J G; Jay, S J

    1983-01-01

    This study examines the influence of physician networks on the utilization of computers in clinical practice. Data on patient referrals, consultations, professional discussions, and on-call coverage were collected from 24 physicians who comprise a private group practice. Their utilization of a computerized hospital medical information system (HIS) in caring for patients admitted to a 1160-bed private, university affiliated, teaching hospital was determined. A matrix representing the professional relations among these physicians was subjected to smallest space analysis, a form of multidimensional scaling. Also, a number of indices that describe structural and interactional properties of the network and individual physicians were computed. The three-dimensional representation of the network that resulted from the analysis suggests a two-step process of adoption and utilization of medical technology. Physicians who were engaged in outside professional activities and in the training of medical students and house staff were more likely to utilize the system in caring for patients. These physicians, who were more centrally located and dominant in the referral and consultation process, were more likely to influence the practice patterns of their colleagues. The use of network analysis to identify influential physicians whose involvement is essential to the success of efforts aimed at introducing computers into clinical practice is discussed. PMID:6827499

  8. A Comparison between the Occurrence of Pauses, Repetitions and Recasts under Conditions of Face-to-Face and Computer-Mediated Communication: A Preliminary Study

    ERIC Educational Resources Information Center

    Cabaroglu, Nese; Basaran, Suleyman; Roberts, Jon

    2010-01-01

    This study compares pauses, repetitions and recasts in matched task interactions under face-to-face and computer-mediated conditions. Six first-year English undergraduates at a Turkish University took part in Skype-based voice chat with a native speaker and face-to-face with their instructor. Preliminary quantitative analysis of transcripts showed…

  9. Preliminary results of very fast computation of Moment Magnitude and focal mechanism in the context of tsunami warning

    NASA Astrophysics Data System (ADS)

    Schindelé, François; Roch, Julien; Rivera, Luis

    2015-04-01

    Various methodologies were recently developed to compute the moment magnitude and the focal mechanism, thanks to the real time access to numerous broad-band seismic data. Several methods were implemented at the CENALT, in particular the W-Phase method developed by H. Kanamori and L. Rivera. For earthquakes of magnitudes in the range 6.5-9.0, this method provides accurate results in less than 40 minutes. The context of the tsunami warning in Mediterranean, a small basin impacted in less than one hour, and with small sources but some with high tsunami potential (Boumerdes 2003), a comprehensive tsunami warning system in that region should include very fast computation of the seismic parameters. The results of the values of Mw, the focal depth and the type of fault (reverse, normal, strike-slip) are the most relevant parameters expected for the tsunami warning. Preliminary results will be presented using data in the North-eastern and Mediterranean region for the recent period 2010-2014. This work is funded by project ASTARTE - - Assessment, Strategy And Risk Reduction for Tsunamis in Europe - FP7-ENV2013 6.4-3, Grant 603839

  10. X-ray phase computed tomography for nanoparticulated imaging probes and therapeutics: preliminary feasibility study

    NASA Astrophysics Data System (ADS)

    Tang, Xiangyang; Yang, Yi; Tang, Shaojie

    2011-03-01

    With the scientific progress in cancer biology, pharmacology and biomedical engineering, the nano-biotechnology based imaging probes and therapeutical agents (namely probes/agents) - a form of theranostics - are among the strategic solutions bearing the hope for the cure of cancer. The key feature distinguishing the nanoparticulated probes/agents from their conventional counterparts is their targeting capability. A large surface-to-volume ratio in nanoparticulated probes/agents enables the accommodation of multiple targeting, imaging and therapeutic components to cope with the intra- and inter-tumor heterogeneity. Most nanoparticulated probes/agents are synthesized with low atomic number materials and thus their x-ray attenuation are very similar to biological tissues. However, their microscopic structures are very different, which may result in significant differences in their refractive properties. Recently, the investigation in the x-ray grating-based differential phase contrast (DPC) CT has demonstrated its advantages in differentiating low-atomic materials over the conventional attenuation-based CT. We believe that a synergy of x-ray grating-based DPC CT and nanoparticulated imaging probes and therapeutic agents may play a significant role in extensive preclinical and clinical applications, or even become a modality for molecular imaging. Hence, we propose to image the refractive property of nanoparticulated imaging probes and therapeutical agents using x-ray grating-based DPC CT. In this work, we conduct a preliminary feasibility study with a focus to characterize the contrast-to-noise ratio (CNR) and contrast-detail behavior of the x-ray grating-based DPC CT. The obtained data may be instructive to the architecture design and performance optimization of the x-ray grating-based DPC CT for imaging biomarker-targeted imaging probes and therapeutic agents, and even informative to the translation of preclinical research in theranostics into clinical applications.

  11. Synopsis of some preliminary computational studies related to unsaturated zone transport at Area G

    SciTech Connect

    Vold, E.

    1998-03-01

    Computational transport models are described with applications in three problem areas related to unsaturated zone moisture movement beneath Area G. These studies may be used to support the ongoing maintenance of the site Performance Assessment. The three areas include: a 1-D transient analysis with average tuff hydraulic properties in the near surface region with computed results compared to field data; the influence on near surface transient moisture percolation due to realistic distributions in hydraulic properties derived statistically from the observed variance in the field data; and the west to east moisture flow in a 2-D steady geometry approximation of the Pajarito Plateau. Results indicate that a simple transient model for transport of moisture volume fraction fits field data well compared to a moisture pulse observed in the active disposal unit, pit 37. Using realistic infiltration boundary conditions for summer showers and for spring snow melt conditions, the computed moisture pulses show significant propagation to less than 10-ft depth. Next, the hydraulic properties were varied on a 2-D grid using statistical distributions based on the field data means and variances for the hydraulic parameters. Near surface transient percolation in these conditions shows a qualitatively realistic percolation with a spatially variable wave front moving into the tuff; however, the flow does not channel into preferred paths and suggests there is no formation of fast paths which could enhance transportation of contaminants. Finally, moisture transport is modeled through an unsaturated 2-D slice representing the upper stratigraphic layers beneath Area G and a west-to-east cut of several miles to examine possible lateral movement from the west where percolation is assumed to be greater than at Area G. Results show some west-to-east moisture flux consistent with the assumed profile for the percolation boundary conditions.

  12. Preliminary application of high-definition computed tomographic Gemstone Spectral Imaging in lung cancer.

    PubMed

    Wang, Guangli; Zhang, Chengqi; Li, Mingying; Deng, Kai; Li, Wei

    2014-01-01

    To evaluate the feasibility of multiparameter quantitative measurement lung cancer by Gemstone Spectral Imaging (GSI) high-definition computed tomography. Seventy-seven patients who were found to have a lung mass or a nodule by CT plain scan for the first time received chest contrast CT scan with GSI mode on high-definition computed tomography. The GSI viewer was used to display the spectral curve, iodine-based images, water-based images, and 101 sets of monochromatic images of a selected region of interest from the relative homogeneous area of the mass or nodule. Iodine concentration, water concentration, spectral curve slope, and CT values at 40 keV of the region of interest were measured. Finally, 68 eligible patients were divided into a pneumonia group (n = 24) and a malignant tumor group (n = 44, including squamous carcinoma, n = 29, and adenocarcinoma, n = 15). Significant differences existed in iodine concentration (t = 6.459), spectral curve slope (t = 6.276), and CT values at 40 keV (t = 6.698) between the pneumonia group and the malignant tumor group (P < 0.05), as well as between squamous carcinoma and adenocarcinoma (t = 6.494, 5.634, 6.091, respectively, P < 0.05), whereas water concentrations were found to have no difference between the 2 groups (t = 0.082, P > 0.05) and between the 2 types of malignant tumors (t = 1.234, P > 0.05). High-definition computed tomographic GSI technique might be helpful to differentiate lung cancer from lung benign lesions by providing qualitative and quantitative information.

  13. Influence of a computer intervention on the psychological status of chronically ill rural women: preliminary results.

    PubMed

    Hill, Wade; Weinert, Clarann; Cudney, Shirley

    2006-01-01

    Adaptation to chronic illness is a lifelong process presenting numerous psychological challenges. It has been shown to be influenced by participating in support groups. Rural women with chronic illness face additional burdens as access to information, healthcare resources, and sources of support are often limited. Developing virtual support groups and testing the effects on psychosocial indicators associated with adaptation to chronic illness may help remove barriers to adaptation. To examine the effects of a computer-delivered intervention on measures of psychosocial health in chronically ill rural women including social support, self-esteem, empowerment, self-efficacy, depression, loneliness, and stress. An experimental design was used to test a computer-delivered intervention and examine differences in psychosocial health between women who participated in the intervention (n = 44) and women in a control group (n = 56). Differences between women who participated in the intervention and controls were found for self-esteem, F(1,98) = 5.97, p =.016; social support, F(1,98) = 4.43, p =.038; and empowerment, F(1,98) = 6.06, p =.016. A comparison of means for depression, loneliness, self-efficacy, and stress suggests that differences for other psychosocial variables are possible. The computer-based intervention tested appears to result in improved self-esteem, social support, and empowerment among rural women with chronic illness. Descriptive but nonsignificant differences were found for other psychosocial variables (depression, loneliness, self-efficacy, and stress); women who participated in the intervention appeared to improve more than women in the control group.

  14. Computed tomography of the meniscus of the temporomandibular joint: preliminary observations

    SciTech Connect

    Helms, C.A.; Morrish, R.B. Jr.; Kircos, L.T.; Dolwick, M.F.

    1982-12-01

    Anterior displacement of the meniscus of the temporomandibular joint (TMJ) was diagnosed in nine patients who had undergone arthrography, and they were later examined with computed tomography (CT) to see if this modality could supplant arthrography in some patients with TMJ dysfunction. The anteriorly displaced menisci were visualizsed in all nine patients by using sagittal reformations and blink mode. Four of the nine patients had the diagnosis confirmed at surgery. The precise protocol for the CT examination and how to interpret it are discussed. We are optimistic that CT may replace TMJ arthrography in selected patients.

  15. Feature Extraction on Brain Computer Interfaces using Discrete Dyadic Wavelet Transform: Preliminary Results

    NASA Astrophysics Data System (ADS)

    Gareis, I.; Gentiletti, G.; Acevedo, R.; Rufiner, L.

    2011-09-01

    The purpose of this work is to evaluate different feature extraction alternatives to detect the event related evoked potential signal on brain computer interfaces, trying to minimize the time employed and the classification error, in terms of sensibility and specificity of the method, looking for alternatives to coherent averaging. In this context the results obtained performing the feature extraction using discrete dyadic wavelet transform using different mother wavelets are presented. For the classification a single layer perceptron was used. The results obtained with and without the wavelet decomposition were compared; showing an improvement on the classification rate, the specificity and the sensibility for the feature vectors obtained using some mother wavelets.

  16. Applications of computer assisted surgery and medical robotics at the ISSSTE, México: preliminary results.

    PubMed

    Mosso, José Luis; Pohl, Mauricio; Jimenez, Juan Ramon; Valdes, Raquel; Yañez, Oscar; Medina, Veronica; Arambula, Fernando; Padilla, Miguel Angel; Marquez, Jorge; Gastelum, Alfonso; Mosso, Alejo; Frausto, Juan

    2007-01-01

    We present the first results of four projects of a second phase of a Mexican Project Computer Assisted Surgery and Medical Robotics, supported by the Mexican Science and Technology National Council (Consejo Nacional de Ciencia y Tecnología) under grant SALUD-2002-C01-8181. The projects are being developed by three universities (UNAM, UAM, ITESM) and the goal of this project is to integrate a laboratory in a Hospital of the ISSSTE to give service to surgeons or clinicians of Endoscopic surgeons, urologist, gastrointestinal endoscopist and neurosurgeons.

  17. A preliminary computer pattern analysis of satellite images of mature extratropical cyclones

    NASA Technical Reports Server (NTRS)

    Burfeind, Craig R.; Weinman, James A.; Barkstrom, Bruce R.

    1987-01-01

    This study has applied computerized pattern analysis techniques to the location and classification of features of several mature extratropical cyclones that were depicted in GOES satellite images. These features include the location of the center of the cyclone vortex core and the location of the associated occluded front. The cyclone type was classified in accord with the scheme of Troup and Streten. The present analysis was implemented on a personal computer; results were obtained within approximately one or two minutes without the intervention of an analyst.

  18. In-tank fluid sloshing effects during earthquakes: A preliminary computational simulation

    SciTech Connect

    Park, J.E.; Rezvani, M.A.

    1995-04-01

    Hundreds of underground radioactive waste storage tanks are located at Department of Energy (DOE) sites. At present, no technique for evaluating the pressure loads due to the impact of earthquake generated waves on the side walls and dome of the tanks is known if the wave breaks back on itself. This paper presents the results of two-dimensional Computational Fluid Dynamics (CFD) calculations of the motion of waves in a generic rectangular tank as the result of accelerations recorded during an earthquake. The advantages and limitations of this technique and methods for avoiding the limitations will be discussed.

  19. Computed nasal resistance compared with patient-reported symptoms in surgically treated nasal airway passages: A preliminary report

    PubMed Central

    Garcia, Guilherme J. M.; Frank, Dennis O.; Cannon, Daniel E.; Pawar, Sachin S.; Rhee, John S.

    2012-01-01

    Background: Nasal airway obstruction (NAO) is a common health condition impacting mood, energy, recreation, sleep, and overall quality of life. Nasal surgery often addresses NAO but the results are sometimes unsatisfactory. Evaluating surgical treatment efficacy could be improved if objective tests were available that correlated with patient-reported measures of symptoms. The goal of this study was to develop methods for comparing nasal resistance computed by computational fluid dynamics (CFD) models with patient-reported symptoms of NAO using early data from a 4-year prospective study. Methods: Computed tomography (CT) scans and patient-reported scores from the Nasal Obstruction Symptom Evaluation (NOSE) scale and a visual analog scale (VAS) measuring unilateral airflow sensation were obtained pre- and postoperatively in two NAO patients showing no significant mucosal asymmetry who were successfully treated with functional nasal surgery, including septoplasty. Pre- and postsurgery CFD models were created from the CT scans. Numerical simulation of steady-state inspiratory airflow was used to calculate bilateral and unilateral CFD-derived nasal resistance (CFD-NR). Results: In both subjects, NOSE and VAS scores improved after surgery, bilateral CFD-NR decreased, and unilateral CFD-NR decreased on the affected side. In addition, NOSE and VAS scores tracked with unilateral CFD-NR on the affected side. Conclusion: These preliminary results suggest a possible correlation between unilateral NR and patient-reported symptoms and imply that analysis of unilateral obstruction should focus on the affected side. A formal investigation of unilateral CFD-NR and patient-reported symptoms in a series of NAO patients is needed to determine if these variables are correlated. PMID:22643935

  20. Computed nasal resistance compared with patient-reported symptoms in surgically treated nasal airway passages: a preliminary report.

    PubMed

    Kimbell, Julia S; Garcia, Guilherme J M; Frank, Dennis O; Cannon, Daniel E; Pawar, Sachin S; Rhee, John S

    2012-01-01

    Nasal airway obstruction (NAO) is a common health condition impacting mood, energy, recreation, sleep, and overall quality of life. Nasal surgery often addresses NAO but the results are sometimes unsatisfactory. Evaluating surgical treatment efficacy could be improved if objective tests were available that correlated with patient-reported measures of symptoms. The goal of this study was to develop methods for comparing nasal resistance computed by computational fluid dynamics (CFD) models with patient-reported symptoms of NAO using early data from a 4-year prospective study. Computed tomography (CT) scans and patient-reported scores from the Nasal Obstruction Symptom Evaluation (NOSE) scale and a visual analog scale (VAS) measuring unilateral airflow sensation were obtained pre- and postoperatively in two NAO patients showing no significant mucosal asymmetry who were successfully treated with functional nasal surgery, including septoplasty. Pre- and postsurgery CFD models were created from the CT scans. Numerical simulation of steady-state inspiratory airflow was used to calculate bilateral and unilateral CFD-derived nasal resistance (CFD-NR). In both subjects, NOSE and VAS scores improved after surgery, bilateral CFD-NR decreased, and unilateral CFD-NR decreased on the affected side. In addition, NOSE and VAS scores tracked with unilateral CFD-NR on the affected side. These preliminary results suggest a possible correlation between unilateral NR and patient-reported symptoms and imply that analysis of unilateral obstruction should focus on the affected side. A formal investigation of unilateral CFD-NR and patient-reported symptoms in a series of NAO patients is needed to determine if these variables are correlated.

  1. Preliminary evaluation of cone beam computed tomography in three-dimensional cephalometry for clinical application

    PubMed Central

    Li, Na; Hu, Bo; Mi, Fanglin; Song, Jinlin

    2017-01-01

    The present study was conducted to evaluate the three-dimensional (3D) cephalometry accuracy of cone-beam computed tomography (CBCT). A total of 40 newly diagnosed orthodontic patients (including 18 males and 22 females; age range, 12–18 years) were subjected to CBCT scanning and X-ray imaging in order to obtain lateral cephalograms. The 3D CBCT cephalograms were reconstructed and measured with in vivo 5.1 software, and compared with the results from the conventional 2D lateral cephalograms. Measurements in the two images were performed twice using the Steiner and Tweed standards and a single analyzer paired t-test was used to analyze the differences between the two cephalometric methods. The results indicated that the two methods showed significant differences in all 12 angle and 5 linear measurements (P<0.05). These findings indicated that CBCT is a more accurate technique compared with the conventional 2D method. In conclusion, CBCT may provide diagnostic and treatment information for maxillofacial deformities by using fast computer-aided analysis platform. PMID:28565862

  2. Group training with healthy computing practices to prevent repetitive strain injury (RSI): a preliminary study.

    PubMed

    Peper, Erik; Gibney, Katherine H; Wilson, Vietta E

    2004-12-01

    This pilot study investigated whether group training, in which participants become role models and coaches, would reduce discomfort as compared to a nontreatment Control Group. Sixteen experimental participants participated in 6 weekly 2-hr group sessions of a Healthy Computing program whereas 12 control participants received no training. None of the participants reported symptoms to their supervisors nor were they receiving medical treatment for repetitive strain injury prior to the program. The program included training in ergonomic principles, psychophysiological awareness and control, sEMG practice at the workstation, and coaching coworkers. Using two-tailed t tests to analyze the data, the Experimental Group reported (1) a significant overall reduction in most body symptoms as compared to the Control Group and (2) a significant increase in positive work-style habits, such as taking breaks at the computer, as compared to the Control Group. This study suggests that employees could possibly improve health and work style patterns based on a holistic training program delivered in a group format followed by individual practice.

  3. Preparing computers for affective communication: a psychophysiological concept and preliminary results.

    PubMed

    Whang, Min Cheol; Lim, Joa Sang; Boucsein, Wolfram

    Despite rapid advances in technology, computers remain incapable of responding to human emotions. An exploratory study was conducted to find out what physiological parameters might be useful to differentiate among 4 emotional states, based on 2 dimensions: pleasantness versus unpleasantness and arousal versus relaxation. The 4 emotions were induced by exposing 26 undergraduate students to different combinations of olfactory and auditory stimuli, selected in a pretest from 12 stimuli by subjective ratings of arousal and valence. Changes in electroencephalographic (EEG), heart rate variability, and electrodermal measures were used to differentiate the 4 emotions. EEG activity separates pleasantness from unpleasantness only in the aroused but not in the relaxed domain, where electrodermal parameters are the differentiating ones. All three classes of parameters contribute to a separation between arousal and relaxation in the positive valence domain, whereas the latency of the electrodermal response is the only differentiating parameter in the negative domain. We discuss how such a psychophysiological approach may be incorporated into a systemic model of a computer responsive to affective communication from the user.

  4. A Statistical Model and Computer program for Preliminary Calculations Related to the Scaling of Sensor Arrays

    SciTech Connect

    Max Morris

    2001-04-01

    Recent advances in sensor technology and engineering have made it possible to assemble many related sensors in a common array, often of small physical size. Sensor arrays may report an entire vector of measured values in each data collection cycle, typically one value per sensor per sampling time. The larger quantities of data provided by larger arrays certainly contain more information, however in some cases experience suggests that dramatic increases in array size do not always lead to corresponding improvements in the practical value of the data. The work leading to this report was motivated by the need to develop computational planning tools to approximate the relative effectiveness of arrays of different size (or scale) in a wide variety of contexts. The basis of the work is a statistical model of a generic sensor array. It includes features representing measurement error, both common to all sensors and independent from sensor to sensor, and the stochastic relationships between the quantities to be measured by the sensors. The model can be used to assess the effectiveness of hypothetical arrays in classifying objects or events from two classes. A computer program is presented for evaluating the misclassification rates which can be expected when arrays are calibrated using a given number of training samples, or the number of training samples required to attain a given level of classification accuracy. The program is also available via email from the first author for a limited time.

  5. The Dutch neuromuscular database CRAMP (Computer Registry of All Myopathies and Polyneuropathies): development and preliminary data.

    PubMed

    van Engelen, B G M; van Veenendaal, H; van Doorn, P A; Faber, C G; van der Hoeven, J H; Janssen, N G; Notermans, N C; van Schaik, I N; Visser, L H; Verschuuren, J J G M

    2007-01-01

    Each of the various neuromuscular diseases is rare. Consequently, solid epidemiological data are not available and it is often difficult to find sufficient patients for studies. For this reason, the Dutch neuromuscular database, CRAMP (Computer Registry of All Myopathies and Polyneuropathies), was developed in 2004 by the Dutch Neuromuscular Research Support Centre, to store information on patient characteristics and diagnoses (based on Rowland and McLeod's classification) in a uniform and easily retrievable manner. Care was taken to preserve data confidentiality. It is envisaged that CRAMP will prove particularly useful for studies in which multicentre collaboration is needed to recruit a sufficiently large number of patients. More than 10,000 patients with neuromuscular diseases (4,837 female, 5,476 male) have been registered since 2004, half of whom (n=5059) have peripheral nerve disorders.

  6. Development of a Computer Program for Analyzing Preliminary Aircraft Configurations in Relationship to Emerging Agility Metrics

    NASA Technical Reports Server (NTRS)

    Bauer, Brent

    1993-01-01

    This paper discusses the development of a FORTRAN computer code to perform agility analysis on aircraft configurations. This code is to be part of the NASA-Ames ACSYNT (AirCraft SYNThesis) design code. This paper begins with a discussion of contemporary agility research in the aircraft industry and a survey of a few agility metrics. The methodology, techniques and models developed for the code are then presented. Finally, example trade studies using the agility module along with ACSYNT are illustrated. These trade studies were conducted using a Northrop F-20 Tigershark aircraft model. The studies show that the agility module is effective in analyzing the influence of common parameters such as thrust-to-weight ratio and wing loading on agility criteria. The module can compare the agility potential between different configurations. In addition, one study illustrates the module's ability to optimize a configuration's agility performance.

  7. Fluid-dynamic computations on a connection machine - Preliminary timings and complex boundary conditions

    NASA Astrophysics Data System (ADS)

    Oran, Elaine S.; Boris, Jay P.; Brown, Eugene F.

    1990-01-01

    This paper describes the conversion and application of the explicit, time-dependent, fourth-order, phase-accurate, variable-grid flux-corrected transport module, LCPFCT, to the Connection Machine, a fine-grained SIMD parallel processor. Models developed are as similar to the production Cray codes as possible and include a variety of different realistic boundary conditions. Timing comparisons show that a 16K-processor Connection Machine allows computations at speeds up to a factor of seven faster than obtained on a Cray YMP for a functionally equivalent optimized, three-dimensional code. Test calculations of a two-dimensional exploding shock and a three-dimensional helically perturbed jet are described and discussed briefly.

  8. The dissemination of computer-based psychological treatment: a preliminary analysis of patient and clinician perceptions.

    PubMed

    Carper, Matthew M; McHugh, R Kathryn; Barlow, David H

    2013-03-01

    Computerized cognitive behavioral therapy is an efficacious treatment for anxiety and depression with the potential to improve access to evidence-based care. However, its adoption in clinical practice in the US has been low and thus there is a need for identification of barriers to its use. We examined treatment-seeking patient (n = 55) and clinician (n = 26) perceptions of computer-based psychological treatment (CBPT) using Diffusion of Innovations theory as a conceptual framework. Diffusion of Innovations theory emphasizes potential adopter perceptions as being key to understanding adoption decisions, thus making it an ideal framework for evaluating barriers to use. Overall, treatment-seeking patients held slightly negative perceptions of CBPT, while clinicians' perceptions were more neutral. In both groups, perceptions of observability (seeing or hearing about the treatment in use) were rated lowest. Implications for dissemination efforts and suggestions for future research are discussed.

  9. Computed tomography in the evaluation of penetrating neck trauma: a preliminary study.

    PubMed

    Gracias, V H; Reilly, P M; Philpott, J; Klein, W P; Lee, S Y; Singer, M; Schwab, C W

    2001-11-01

    Penetrating neck trauma has traditionally been evaluated by surgical exploration and/or invasive diagnostic studies. We hypothesized that computed tomography (CT), used as an early diagnostic tool to accurately determine trajectory, would direct or eliminate further studies or procedures in stable patients with penetrating neck trauma. Retrospective case series. Academic, urban, level I trauma center. Hemodynamically stable patients without hard signs of vascular injury or aerodigestive violation who had sustained penetrating trauma to the neck. Patients underwent a spiral CT as an initial diagnostic study after initial evaluation in the trauma bay. Further invasive studies were directed by CT findings. Number of invasive studies performed. Twenty-three patients were identified during the 30-month period. Nineteen patients sustained gunshot wounds; 3, shotgun wounds; and 1, a stab wound. One patient died of a cranial gunshot wound. Three isolated zone I, 1 isolated zone II, 9 isolated zone III, and 10 multiple neck zone trajectories were evaluated. Thirteen patients were identified by CT to have trajectories remote from vital structures and required no further evaluation. Ten patients underwent angiography. Only 2 underwent bronchoscopy and esophagoscopy. Four patients were discharged from the emergency department; 7 other patients were discharged within 24 hours. No adverse patient events occurred before, during, or after CT scan. Computed tomography in stable selected patients with penetrating neck trauma appears safe. Invasive studies can often be eliminated from the diagnostic algorithm when CT demonstrates trajectories remote from vital structures. As a result, efficient evaluation and early discharge from the trauma bay or emergency department can be realized. Further prospective study of CT scan after penetrating neck trauma is needed.

  10. A preliminary 3D computed tomography study of the human maxillary sinus and nasal cavity.

    PubMed

    Butaric, Lauren N; McCarthy, Robert C; Broadfield, Douglas C

    2010-11-01

    Despite centuries of investigation, the function of the maxillary sinus (MS) and underlying patterns governing its form remain elusive. In this study, we articulate a methodology for collecting volumetric data for the MS and nasal cavity (NC) from computed tomography (CT) scans and report details for a small sample of 39 dried human crania of known ecogeographic provenience useful for assessing variation in MS size and shape. We use scaling analyses to preliminarily test the hypothesis that volumes of the nasal cavity (NCV) and maxillary sinus (MSV) are inversely correlated such that the NC covaries with size of the face, whereas the MS "fills in" the leftover space [proposed by Shea: Am J Phys Anthropol 47 (1977):289-300]. Against expectation, MSV is not significantly correlated with NCV or any cranial size variable. NCV, on the other hand, scales isometrically with facial size. The results of this pilot study suggest that NCV covaries with facial size, but that the MS does not simply fill in the leftover space in the face. The role, if any, of the MSs in midfacial function and architecture remains unclear. Larger sample sizes, additional environmental variables, and assessment of MS and NC shape are necessary to resolve this issue.

  11. Preliminary validation of computational procedures for a new atmospheric ionizing radiation (AIR) model.

    PubMed

    Clem, John M; De Angelis, Giovanni; Goldhagen, Paul; Wilson, John W

    2003-01-01

    A new computational procedure to determine particle fluxes in the Earth's atmosphere is presented. The primary cosmic ray spectrum has been modeled through an analysis of simultaneous proton and helium measurements made on high altitude balloon flights and spacecraft. An improved global fit to the data was achieved through applying a unique technique utilizing the Fokker-Plank equation with a non-linear rigidity-dependent diffusion coefficient. The propagation of primary particles through the Earth's atmosphere is calculated with a three-dimensional Monte Carlo transport program called FLUKA. Primary protons and helium nuclei (alphas) are generated within the rigidity range of 0.5 GV-20 TV uniform in cos2 theta. For a given location, primaries above the effective cutoff rigidity are transported through the atmosphere. Alpha particles are initially transported with a separate package called HEAVY to simulate fragmentation. This package interfaces with FLUKA to provide interaction starting points for each nucleon originating from a helium nucleus. Results from this calculation are presented and compared to measurements.

  12. Using Gender Schema Theory to Examine Gender Equity in Computing: a Preliminary Study

    NASA Astrophysics Data System (ADS)

    Agosto, Denise E.

    Women continue to constitute a minority of computer science majors in the United States and Canada. One possible contributing factor is that most Web sites, CD-ROMs, and other digital resources do not reflect girls' design and content preferences. This article describes a pilot study that considered whether gender schema theory can serve as a framework for investigating girls' Web site design and content preferences. Eleven 14- and 15-year-old girls participated in the study. The methodology included the administration of the Children's Sex-Role Inventory (CSRI), Web-surfing sessions, interviews, and data analysis using iterative pattern coding. On the basis of their CSRI scores, the participants were divided into feminine-high (FH) and masculine-high (MH) groups. Data analysis uncovered significant differences in the criteria the groups used to evaluate Web sites. The FH group favored evaluation criteria relating to graphic and multimedia design, whereas the MH group favored evaluation criteria relating to subject content. Models of the two groups' evaluation criteria are presented, and the implications of the findings are discussed.

  13. A preliminary analysis of quantifying computer security vulnerability data in "the wild"

    NASA Astrophysics Data System (ADS)

    Farris, Katheryn A.; McNamara, Sean R.; Goldstein, Adam; Cybenko, George

    2016-05-01

    A system of computers, networks and software has some level of vulnerability exposure that puts it at risk to criminal hackers. Presently, most vulnerability research uses data from software vendors, and the National Vulnerability Database (NVD). We propose an alternative path forward through grounding our analysis in data from the operational information security community, i.e. vulnerability data from "the wild". In this paper, we propose a vulnerability data parsing algorithm and an in-depth univariate and multivariate analysis of the vulnerability arrival and deletion process (also referred to as the vulnerability birth-death process). We find that vulnerability arrivals are best characterized by the log-normal distribution and vulnerability deletions are best characterized by the exponential distribution. These distributions can serve as prior probabilities for future Bayesian analysis. We also find that over 22% of the deleted vulnerability data have a rate of zero, and that the arrival vulnerability data is always greater than zero. Finally, we quantify and visualize the dependencies between vulnerability arrivals and deletions through a bivariate scatterplot and statistical observations.

  14. Automatic, computer-based speech assessment on edentulous patients with and without complete dentures - preliminary results.

    PubMed

    Stelzle, F; Ugrinovic, B; Knipfer, C; Bocklet, T; Nöth, E; Schuster, M; Eitner, S; Seiss, M; Nkenke, E

    2010-03-01

    Dental rehabilitation of edentulous patients with complete dentures includes not only aesthetics and mastication of food, but also speech quality. It was the aim of this study to introduce and validate a computer-based speech recognition system (ASR) for automatic speech assessment in edentulous patients after dental rehabilitation with complete dentures. To examine the impact of dentures on speech production, the speech outcome of edentulous patients with and without complete dentures was compared. Twenty-eight patients reading a standardized text were recorded twice - with and without their complete dentures in situ. A control group of 40 healthy subjects with natural dentition was recorded under the same conditions. Speech quality was evaluated by means of a polyphone-based ASR according to the percentage of the word accuracy (WA). Speech acceptability assessment by expert listeners and the automatic rating of the WA by the ASR showed a high correlation (corr = 0.71). Word accuracy was significantly reduced in edentulous speakers (55.42 +/- 13.1) compared to the control group's WA (69.79 +/- 10.6). On the other hand, wearing complete dentures significantly increased the WA of the edentulous patients (60.00 +/- 15.6). Speech production quality is significantly reduced after complete loss of teeth. Reconstitution of speech production quality is an important part of dental rehabilitation and can be improved for edentulous patients by means of complete dentures. The ASR has proven to be a useful and easily applicable tool for automatic speech assessment in a standardized way.

  15. Preliminary results of BRAVO project: brain computer interfaces for Robotic enhanced Action in Visuo-motOr tasks.

    PubMed

    Bergamasco, Massimo; Frisoli, Antonio; Fontana, Marco; Loconsole, Claudio; Leonardis, Daniele; Troncossi, Marco; Foumashi, Mohammad Mozaffari; Parenti-Castelli, Vincenzo

    2011-01-01

    This paper presents the preliminary results of the project BRAVO (Brain computer interfaces for Robotic enhanced Action in Visuo-motOr tasks). The objective of this project is to define a new approach to the development of assistive and rehabilitative robots for motor impaired users to perform complex visuomotor tasks that require a sequence of reaches, grasps and manipulations of objects. BRAVO aims at developing new robotic interfaces and HW/SW architectures for rehabilitation and regain/restoration of motor function in patients with upper limb sensorimotor impairment through extensive rehabilitation therapy and active assistance in the execution of Activities of Daily Living. The final system developed within this project will include a robotic arm exoskeleton and a hand orthosis that will be integrated together for providing force assistance. The main novelty that BRAVO introduces is the control of the robotic assistive device through the active prediction of intention/action. The system will actually integrate the information about the movement carried out by the user with a prediction of the performed action through an interpretation of current gaze of the user (measured through eye-tracking), brain activation (measured through BCI) and force sensor measurements.

  16. Effectiveness of systematic articulation training program accessing computers (SATPAC) approach to remediate dentalized and interdental /s, z/: a preliminary study.

    PubMed

    Flipsen, Peter; Sacks, Stephen; Neils-Strunjas, Jean

    2013-10-01

    Traditional methods for treating speech distortion errors in older school-age children have tended to yield mixed success. The current study was a preliminary evaluation of an alternative approach called the Systematic Articulation Training Program Accessing Computers (SATPAC), which was tested for the remediation of /s/ and /z/. Procedures involved a sequence of phonetic placement and/or oral-motor placement cues as needed to establish the targets, followed by concentrated drill structured around a facilitating context nonsense word and then advanced to more natural contexts. Participants were 18 children aged 6 years, 9 months to 11 years, 10 months. Treatment involved once per week, individual, 10-min. sessions with an experienced speech-language pathologist. Group A (n = 9) received 15 weeks of treatment, while treatment was delayed for Group B (n = 9). Then the groups were reversed. During period one, Group A (treated) significantly improved their accuracy of /s, z/ in spontaneous speech, while Group B (untreated) showed no significant change. During period two, Group B improved significantly when treatment was applied. The majority of the participants retained proficiency two years later.

  17. Functionalized synchrotron in-line phase-contrast computed tomography: a novel approach for simultaneous quantification of structural alterations and localization of barium-labelled alveolar macrophages within mouse lung samples

    PubMed Central

    Dullin, Christian; dal Monego, Simeone; Larsson, Emanuel; Mohammadi, Sara; Krenkel, Martin; Garrovo, Chiara; Biffi, Stefania; Lorenzon, Andrea; Markus, Andrea; Napp, Joanna; Salditt, Tim; Accardo, Agostino; Alves, Frauke; Tromba, Giuliana

    2015-01-01

    Functionalized computed tomography (CT) in combination with labelled cells is virtually non-existent due to the limited sensitivity of X-ray-absorption-based imaging, but would be highly desirable to realise cell tracking studies in entire organisms. In this study we applied in-line free propagation X-ray phase-contrast CT (XPCT) in an allergic asthma mouse model to assess structural changes as well as the biodistribution of barium-labelled macrophages in lung tissue. Alveolar macrophages that were barium-sulfate-loaded and fluorescent-labelled were instilled intratracheally into asthmatic and control mice. Mice were sacrificed after 24 h, lungs were kept in situ, inflated with air and scanned utilizing XPCT at the SYRMEP beamline (Elettra Synchrotron Light Source, Italy). Single-distance phase retrieval was used to generate data sets with ten times greater contrast-to-noise ratio than absorption-based CT (in our setup), thus allowing to depict and quantify structural hallmarks of asthmatic lungs such as reduced air volume, obstruction of airways and increased soft-tissue content. Furthermore, we found a higher concentration as well as a specific accumulation of the barium-labelled macrophages in asthmatic lung tissue. It is believe that XPCT will be beneficial in preclinical asthma research for both the assessment of therapeutic response as well as the analysis of the role of the recruitment of macrophages to inflammatory sites. PMID:25537601

  18. Functionalized synchrotron in-line phase-contrast computed tomography: a novel approach for simultaneous quantification of structural alterations and localization of barium-labelled alveolar macrophages within mouse lung samples.

    PubMed

    Dullin, Christian; dal Monego, Simeone; Larsson, Emanuel; Mohammadi, Sara; Krenkel, Martin; Garrovo, Chiara; Biffi, Stefania; Lorenzon, Andrea; Markus, Andrea; Napp, Joanna; Salditt, Tim; Accardo, Agostino; Alves, Frauke; Tromba, Giuliana

    2015-01-01

    Functionalized computed tomography (CT) in combination with labelled cells is virtually non-existent due to the limited sensitivity of X-ray-absorption-based imaging, but would be highly desirable to realise cell tracking studies in entire organisms. In this study we applied in-line free propagation X-ray phase-contrast CT (XPCT) in an allergic asthma mouse model to assess structural changes as well as the biodistribution of barium-labelled macrophages in lung tissue. Alveolar macrophages that were barium-sulfate-loaded and fluorescent-labelled were instilled intratracheally into asthmatic and control mice. Mice were sacrificed after 24 h, lungs were kept in situ, inflated with air and scanned utilizing XPCT at the SYRMEP beamline (Elettra Synchrotron Light Source, Italy). Single-distance phase retrieval was used to generate data sets with ten times greater contrast-to-noise ratio than absorption-based CT (in our setup), thus allowing to depict and quantify structural hallmarks of asthmatic lungs such as reduced air volume, obstruction of airways and increased soft-tissue content. Furthermore, we found a higher concentration as well as a specific accumulation of the barium-labelled macrophages in asthmatic lung tissue. It is believe that XPCT will be beneficial in preclinical asthma research for both the assessment of therapeutic response as well as the analysis of the role of the recruitment of macrophages to inflammatory sites.

  19. Application of Gemstone Spectral Computed Tomography Imaging in the Characterization of Solitary Pulmonary Nodules: Preliminary Result.

    PubMed

    Lin, Ji-Zheng; Zhang, Liang; Zhang, Chuan-Yu; Yang, Lei; Lou, He-Nan; Wang, Ze-Guo

    This study aimed to observe the value of computed tomography (CT) spectral imaging parameters in the diagnosis of solitary pulmonary nodules, during the contrast-enhanced early phase and late phase. This study was approved by the institutional review board and written informed consent was obtained from all patients. One hundred thirty-nine patients with solitary pulmonary nodules proved by pathology underwent double-phase enhanced CT scan using gemstone spectral imaging mode on a Discovery CT750 HD, and were divided into an active inflammatory group (43 cases), a malignant group (65 cases), and a tuberculosis group (31 cases). The slope rate was calculated from the spectral curve. Iodine concentrations (ICs) were derived from iodine-based material decomposition CT images and normalized to the IC in the aorta. The Kruskal-Wallis test and Nemenyi test were performed to compare quantitative parameters among the 3 groups or between each of the 2 groups. There were significant differences in the slope rate, IC, and normalized IC (NIC) among the 3 groups. In the active inflammatory group, malignant group, and tuberculosis group, the mean slope rate were 3.03 ± 0.71 (SD), 1.96 ± 0.91, and 1.37 ± 0.43, respectively, during the early phase and 3.28 ± 0.67, 2.24 ± 0.82, and 1.67 ± 0.64, respectively, during the late phase. The ICs were 2.68 mg/mL ± 0.56, 1.65 mg/mL ± 0.76, and 1.10 mg/mL ± 0.34, respectively, during the early phase and 2.79 mg/mL ± 0.57, 1.90 mg/mL ± 0.71, and 1.29 mg/mL ± 0.44, respectively, during the late phase. The NIC were 0.24 ± 0.06, 0.16 ± 0.04, and 0.10 ± 0.04, respectively, during the early phase and 0.57 ± 0.10, 0.43 ± 0.11, and 0.25 ± 0.09, respectively, during the late phase. The mean slope rate, IC, and NIC for the active inflammatory group were significantly higher than these parameters for the malignant group (P < 0.05), and the parameters for malignant group were significantly higher than the tuberculosis group (P < 0

  20. Optical computed tomography utilizing a rotating mirror and Fresnel lenses: operating principles and preliminary results

    NASA Astrophysics Data System (ADS)

    Xu, Y.; Wuu, Cheng-Shie

    2013-02-01

    The performance of a fast optical computed tomography (CT) scanner based on a point laser source, a small area photodiode detector, and two optical-grade Fresnel lenses is evaluated. The OCTOPUS™-10× optical CT scanner (MGS Research Inc., Madison, CT) is an upgrade of the OCTOPUS™ research scanner with improved design for faster motion of the laser beam and faster data acquisition process. The motion of the laser beam in the new configuration is driven by the rotational motion of a scanning mirror. The center of the scanning mirror and the center of the photodiode detector are adjusted to be on the focal points of two coaxial Fresnel lenses. A glass water tank is placed between the two Fresnel lenses to house gel phantoms and matching liquids. The laser beam scans over the water tank in parallel beam geometry for projection data as the scanning mirror rotates at a frequency faster than 0.1 s per circle. Signal sampling is performed independently of the motion of the scanning mirror, to reduce the processing time for the synchronization of the stepper motors and the data acquisition board. An in-house developed reference image normalization mechanism is added to the image reconstruction program to correct the non-uniform light transmitting property of the Fresnel lenses. Technical issues with regard to the new design of the scanner are addressed, including projection data extraction from raw data samples, non-uniform pixel averaging and reference image normalization. To evaluate the dosimetric accuracy of the scanner, the reconstructed images from a 16 MeV, 6 cm × 6 cm electron field irradiation were compared with those from the Eclipse treatment planning system (Varian Corporation, Palo Alto, CA). The spatial resolution of the scanner is demonstrated to be of sub-millimeter accuracy. The effectiveness of the reference normalization method for correcting the non-uniform light transmitting property of the Fresnel lenses is analyzed. A sub-millimeter accuracy of

  1. Reproducibility of coronary atherosclerotic plaque characteristics in populations with low, intermediate, and high prevalence of coronary artery disease by multidetector computer tomography: a guide to reliable visual coronary plaque assessments.

    PubMed

    de Knegt, Martina C; Linde, Jesper J; Fuchs, Andreas; Nordestgaard, Børge G; Køber, Lars V; Hove, Jens D; Kofoed, Klaus F

    2016-10-01

    To evaluate the interobserver agreement of visual coronary plaque characteristics by 320-slice multidetector computed tomography (MDCT) in three populations with low, intermediate and high CAD prevalence and to identify determinants for the reproducible assessment of these plaque characteristics. 150 patients, 50 asymptomatic subjects from the general population (low CAD prevalence), 50 symptomatic non-acute coronary syndrome (non-ACS) patients (intermediate CAD prevalence), and 50 ACS patients (high CAD prevalence), matched according to age and gender, were retrospectively enrolled. All coronary segments were evaluated for overall image quality, evaluability, presence of CAD, coronary stenosis, plaque composition, plaque focality, and spotty calcification by four readers. Interobserver agreement was assessed using Fleiss' Kappa (κ) and intra-class correlation (ICC). Widely used clinical parameters (overall scan quality, presence of CAD, and determination of coronary stenosis) showed good agreement among the four readers, (ICC = 0.66, κ = 0.73, ICC = 0.74, respectively). When accounting for heart rate, body mass index, plaque location, and coronary stenosis above/below 50 %, interobserver agreement for plaque composition, presence of CAD, and coronary stenosis improved to either good or excellent, (κ = 0.61, κ = 0.81, ICC = 0.78, respectively). Spotty calcification was the least reproducible parameter investigated (κ = 0.33). Across subpopulations, reproducibility of coronary plaque characteristics generally decreased with increasing CAD prevalence except for plaque composition, (limits of agreement: ±2.03, ±1.96, ±1.79 for low, intermediate and high CAD prevalence, respectively). 320-slice MDCT can be used to assess coronary plaque characteristics, except for spotty calcification. Reproducibility estimates are influenced by heart rate, body size, plaque location, and degree of luminal stenosis.

  2. The use of a novel cleaning closed suction system reduces the volume of secretions within the endotracheal tube as assessed by micro-computed tomography: a randomized clinical trial.

    PubMed

    Coppadoro, Andrea; Bellani, Giacomo; Bronco, Alfio; Lucchini, Alberto; Bramati, Simone; Zambelli, Vanessa; Marcolin, Roberto; Pesenti, Antonio

    2015-12-01

    Early after intubation, a layer of biofilm covers the inner lumen of the endotracheal tube (ETT). Cleaning the ETT might prevent airways colonization by pathogens, reduce resistance to airflow, and decrease sudden ETT obstruction. We investigated the effectiveness of a cleaning closed suction system in maintaining the endotracheal tube free from secretions. We conducted a single center, randomized controlled trial, in the general intensive care unit of a tertiary-level university hospital. We enrolled 40 adult critically ill patients expected to remain intubated for more than 48 h, within 24 h from intubation. Patients were randomized to receive three ETT cleaning maneuvers/day using a novel device (Airway Medix Closed Suction System™, cleaning group) or to standard care (no ETT cleaning, standard closed suction, control group). After extubation, the amount of secretions in the ETTs was measured by micro-computed tomography. The volume of secretions in the ETTs from the cleaning group was lower than controls (0.081 [0.021-0.306] vs. 0.568 [0.162-0.756] mL, p = 0.001), corresponding to a cross-sectional area reduction six times lower (1[0-3] vs. 6 [2-10] %, p = 0.001). In a subset of 16 patients, the resistance to airflow tended to be lower after 1 day of treatment (p = 0.063) and was lower after 2 days (0.024), while no difference was present at enrollment (p = 0.922). ETT colonization did not differ between the two groups. The use of a novel cleaning closed suction system proved to be effective in reducing secretions present in the ETT after extubation, possibly reducing resistance to airflow during intubation. clinicaltrials.gov NCT01912105.

  3. Optical computed tomography utilizing a rotating mirror and Fresnel lenses: operating principles and preliminary results.

    PubMed

    Xu, Y; Wuu, Cheng-Shie

    2013-02-07

    The performance of a fast optical computed tomography (CT) scanner based on a point laser source, a small area photodiode detector, and two optical-grade Fresnel lenses is evaluated. The OCTOPUS™-10× optical CT scanner (MGS Research Inc., Madison, CT) is an upgrade of the OCTOPUS™ research scanner with improved design for faster motion of the laser beam and faster data acquisition process. The motion of the laser beam in the new configuration is driven by the rotational motion of a scanning mirror. The center of the scanning mirror and the center of the photodiode detector are adjusted to be on the focal points of two coaxial Fresnel lenses. A glass water tank is placed between the two Fresnel lenses to house gel phantoms and matching liquids. The laser beam scans over the water tank in parallel beam geometry for projection data as the scanning mirror rotates at a frequency faster than 0.1 s per circle. Signal sampling is performed independently of the motion of the scanning mirror, to reduce the processing time for the synchronization of the stepper motors and the data acquisition board. An in-house developed reference image normalization mechanism is added to the image reconstruction program to correct the non-uniform light transmitting property of the Fresnel lenses. Technical issues with regard to the new design of the scanner are addressed, including projection data extraction from raw data samples, non-uniform pixel averaging and reference image normalization. To evaluate the dosimetric accuracy of the scanner, the reconstructed images from a 16 MeV, 6 cm × 6 cm electron field irradiation were compared with those from the Eclipse treatment planning system (Varian Corporation, Palo Alto, CA). The spatial resolution of the scanner is demonstrated to be of sub-millimeter accuracy. The effectiveness of the reference normalization method for correcting the non-uniform light transmitting property of the Fresnel lenses is analyzed. A sub

  4. Cloud Computing-based Platform for Drought Decision-Making using Remote Sensing and Modeling Products: Preliminary Results for Brazil

    NASA Astrophysics Data System (ADS)

    Vivoni, E.; Mascaro, G.; Shupe, J. W.; Hiatt, C.; Potter, C. S.; Miller, R. L.; Stanley, J.; Abraham, T.; Castilla-Rubio, J.

    2012-12-01

    Droughts and their hydrological consequences are a major threat to food security throughout the world. In arid and semiarid regions dependent on irrigated agriculture, prolonged droughts lead to significant and recurring economic and social losses. In this contribution, we present preliminary results on integrating a set of multi-resolution drought indices into a cloud computing-based visualization platform. We focused our initial efforts on Brazil due to a severe, on-going drought in a large agricultural area in the northeastern part of the country. The online platform includes drought products developed from: (1) a MODIS-based water stress index (WSI) based on inferences from normalized difference vegetation index and land surface temperature fields, (2) a volumetric water content (VWC) index obtained from application of the NASA CASA model, and (3) a set of AVHRR-based vegetation health indices obtained from NOAA/NESDIS. The drought indices are also presented in terms of anomalies with respect to a baseline period. Since our main objective is to engage stakeholders and decision-makers in Brazil, we incorporated other relevant geospatial data into the platform, including irrigation areas, dams and reservoirs, administrative units and annual climate information. We will also present a set of use cases developed to help stakeholders explore, query and provide feedback that allowed fine-tuning of the drought product delivery, presentation and analysis tools. Finally, we discuss potential next steps in development of the online platform, including applications at finer resolutions in specific basins and at a coarser global scale.

  5. Volume assessment accuracy in computed tomography: a phantom study

    PubMed Central

    Prionas, Nicolas D.; Ray, Shonket; Boone, John M.

    2011-01-01

    There is a broad push in the cancer imaging community to eventually replace linear tumor measurements with three-dimensional evaluation of tumor volume. To evaluate the potential accuracy of volume measurement in tumors by CT, a gelatin phantom consisting of 55 polymethylmethacrylate (PMMA) spheres spanning diameters from 1.6 mm to 25.4 mm was fabricated and scanned using thin slice (0.625 mm) CT (GE LightSpeed 16). Nine different reconstruction combinations of field of view dimension (FOV = 20, 30, 40 cm) and CT kernel (standard, lung, bone) were analyzed. Contiguous thin-slice images were averaged to produce CT images with greater thicknesses (1.25, 2.50, 5.0 mm). Simple grayscale thresholding techniques were used to segment the PMMA spheres from the gelatin background, where a total of 1800 spherical volumes were evaluated across the permutations studied. The geometric simplicity of the phantom established upper limits on measurement accuracy. In general, smaller slice thickness and larger sphere diameters produced more accurate volume assessment than larger slice thickness and smaller sphere diameter. The measured volumes were smaller than the actual volumes by a common factor depending on slice thickness; overall, 0625 mm slices produced on average 18%, 1.25 mm slices produced 22%, 2.5 mm CT slices produced 29%, and 5.0 mm slices produced 39% underestimates of volume (mm3). Field of view did not have a significant effect on volume accuracy. Reconstruction algorithm significantly affected volume accuracy (p < 0.0001), with the lung kernel having the smallest error, followed by the bone and standard kernels. The results of this investigation provide guidance for CT protocol development and may guide the development of more advanced techniques to promote quantitatively accurate CT volumetric analysis of tumors. PMID:20592693

  6. Nanotechnology for computed tomography: a real potential recently disclosed.

    PubMed

    Anton, Nicolas; Vandamme, Thierry F

    2014-01-01

    In the last decade, nanomaterials have gained considerable attention and interest in the development of new and efficient molecular probes for medical diagnosis and imaging. Compared to traditional contrast agents used from the 70s, this comes from the new possibilities offered by the increased half-life of nanosystems in blood stream, as well as by the specific accumulation in organ of lesions through passive or active targeting mechanisms. Heavy metal or iodinated-loaded nanoparticles are excellent absorbers of X-rays and can offer excellent improvement in medical diagnosis and X-ray imaging. This review aims to propose an accurate state-of-the-art of the emerging applications of nanotechnology in X-ray imaging. Likewise we will discuss and compare all the solutions proposed, and the impact of their composition, formulation methods, and physicochemical properties on their applications, efficiency, and potential industrial scaling-up.

  7. The Uses of Computers in High Schools. A Teacher's Manual Prepared by the Teachers of the Huntington Computer Project. Preliminary Version.

    ERIC Educational Resources Information Center

    Braun, Ludwig; Visich, Marian, Jr.

    The material presented in this three-volume manual is a summary of the history and experiences of the Huntington Computer Project, and the purpose of the manual is to assist high school teachers and other educators who wish to explore the uses of computers in high schools. The first volume contains an introductory section which gives the…

  8. The Uses of Computers in High Schools. A Teacher's Manual Prepared by the Teachers of the Huntington Computer Project. Preliminary Version.

    ERIC Educational Resources Information Center

    Braun, Ludwig; Visich, Marian, Jr.

    The material presented in this three-volume manual is a summary of the history and experiences of the Huntington Computer Project, and the purpose of the manual is to assist high school teachers and other educators who wish to explore the uses of computers in high schools. The first volume contains an introductory section which gives the…

  9. Computer-Assisted Learning in Anatomy at the International Medical School in Debrecen, Hungary: A Preliminary Report

    ERIC Educational Resources Information Center

    Kish, Gary; Cook, Samuel A.; Kis, Greta

    2013-01-01

    The University of Debrecen's Faculty of Medicine has an international, multilingual student population with anatomy courses taught in English to all but Hungarian students. An elective computer-assisted gross anatomy course, the Computer Human Anatomy (CHA), has been taught in English at the Anatomy Department since 2008. This course focuses on an…

  10. Computer-Assisted Learning in Anatomy at the International Medical School in Debrecen, Hungary: A Preliminary Report

    ERIC Educational Resources Information Center

    Kish, Gary; Cook, Samuel A.; Kis, Greta

    2013-01-01

    The University of Debrecen's Faculty of Medicine has an international, multilingual student population with anatomy courses taught in English to all but Hungarian students. An elective computer-assisted gross anatomy course, the Computer Human Anatomy (CHA), has been taught in English at the Anatomy Department since 2008. This course focuses on an…

  11. Preliminary Analysis of a Randomized Trial of Computer Attention Training in Children with Attention-Deficit/Hyperactivity Disorder

    ERIC Educational Resources Information Center

    Steiner, N.; Sidhu, T. K.; Frenette, E. C.; Mitchell, K.; Perrin, E. C.

    2011-01-01

    Clinically significant attention problems among children present a significant obstacle to increasing student achievement. Computer-based attention training holds great promise as a way for schools to address this problem. The aim of this project is to evaluate the efficacy of two computer-based attention training systems in schools. One program…

  12. Monitoring the Microgravity Environment Quality On-board the International Space Station Using Soft Computing Techniques. Part 2; Preliminary System Performance Results

    NASA Technical Reports Server (NTRS)

    Jules, Kenol; Lin, Paul P.; Weiss, Daniel S.

    2002-01-01

    This paper presents the preliminary performance results of the artificial intelligence monitoring system in full operational mode using near real time acceleration data downlinked from the International Space Station. Preliminary microgravity environment characterization analysis result for the International Space Station (Increment-2), using the monitoring system is presented. Also, comparison between the system predicted performance based on ground test data for the US laboratory "Destiny" module and actual on-orbit performance, using measured acceleration data from the U.S. laboratory module of the International Space Station is presented. Finally, preliminary on-orbit disturbance magnitude levels are presented for the Experiment of Physics of Colloids in Space, which are compared with on ground test data. The ground test data for the Experiment of Physics of Colloids in Space were acquired from the Microgravity Emission Laboratory, located at the NASA Glenn Research Center, Cleveland, Ohio. The artificial intelligence was developed by the NASA Glenn Principal Investigator Microgravity Services Project to help the principal investigator teams identify the primary vibratory disturbance sources that are active, at any moment of time, on-board the International Space Station, which might impact the microgravity environment their experiments are exposed to. From the Principal Investigator Microgravity Services' web site, the principal investigator teams can monitor via a dynamic graphical display, implemented in Java, in near real time, which event(s) is/are on, such as crew activities, pumps, fans, centrifuges, compressor, crew exercise, structural modes, etc., and decide whether or not to run their experiments, whenever that is an option, based on the acceleration magnitude and frequency sensitivity associated with that experiment. This monitoring system detects primarily the vibratory disturbance sources. The system has built-in capability to detect both known

  13. Comparison of Spinal Angles in a Typing Task on a Laptop and a Desktop Computer: A Preliminary Study.

    PubMed

    Alyami, Hiedar; Albarrati, Ali M

    This study's objective was to discover whether a difference exists in four postural angles while performing a typing task on a laptop and a desktop computer. Twenty healthy participants performed a 5-min typing task on each computer. Statistically significant differences for all angles were found when comparing sitting at the desktop computer with sitting at the laptop. Neck angle (p < .0005), head tilt (p < .0005), and lumbar lordosis (p = .018) were significantly higher when using the laptop. The greatest posterior pelvic tilt was associated with the desktop (p = .018). A desktop appears to be more appropriate for the cervical and lumbar regions; however, using a laptop may be more suitable for pelvic tilt.

  14. Modeling resident error-making patterns in detection of mammographic masses using computer-extracted image features: preliminary experiments

    NASA Astrophysics Data System (ADS)

    Mazurowski, Maciej A.; Zhang, Jing; Lo, Joseph Y.; Kuzmiak, Cherie M.; Ghate, Sujata V.; Yoon, Sora

    2014-03-01

    Providing high quality mammography education to radiology trainees is essential, as good interpretation skills potentially ensure the highest benefit of screening mammography for patients. We have previously proposed a computer-aided education system that utilizes trainee models, which relate human-assessed image characteristics to interpretation error. We proposed that these models be used to identify the most difficult and therefore the most educationally useful cases for each trainee. In this study, as a next step in our research, we propose to build trainee models that utilize features that are automatically extracted from images using computer vision algorithms. To predict error, we used a logistic regression which accepts imaging features as input and returns error as output. Reader data from 3 experts and 3 trainees were used. Receiver operating characteristic analysis was applied to evaluate the proposed trainee models. Our experiments showed that, for three trainees, our models were able to predict error better than chance. This is an important step in the development of adaptive computer-aided education systems since computer-extracted features will allow for faster and more extensive search of imaging databases in order to identify the most educationally beneficial cases.

  15. A Framework for Measuring Student Learning Gains and Engagement in an Introductory Computing Course: A Preliminary Report of Findings

    ERIC Educational Resources Information Center

    Lim, Billy; Hosack, Bryan; Vogt, Paul

    2012-01-01

    This paper describes a framework for measuring student learning gains and engagement in a Computer Science 1 (CS 1) / Information Systems 1 (IS 1) course. The framework is designed for a CS1/IS1 course as it has been traditionally taught over the years as well as when it is taught using a new pedagogical approach with Web services. It enables the…

  16. The Opinions of the Kindergarten Teachers in Relation to the Introduction of Computers to Nursery Schools: Preliminary Approach

    ERIC Educational Resources Information Center

    Sivropoulou, Irene; Tsapakidou, Aggeliki; Kiridis, Argyris

    2009-01-01

    Computers were introduced in Greek kindergartens of our country with the new curricula for kindergarten, "Inter-disciplinary Integrated Framework of Study Programs," ("Official Journal of the Hellenic Republic," 376 t.B/18-10-2001, article 6), in order to contribute to the spherical growth of children and to extend their…

  17. Second-Grade Urban Learners: Preliminary Findings for a Computer-Assisted, Culturally Relevant, Repeated Reading Intervention

    ERIC Educational Resources Information Center

    Bennett, Jessica G.; Gardner, Ralph, III; Cartledge, Gwendolyn; Ramnath, Rajiv; Council, Morris R., III

    2017-01-01

    This study investigated the effects of a multicomponent, supplemental intervention on the reading fluency of second-grade African-American urban students who showed reading and special education risk. The packaged intervention combined repeated readings and culturally relevant stories, delivered through a novel computer software program to enhance…

  18. Preliminary Development of a Workstation for Craniomaxillofacial Surgical Procedures: Introducing a Computer-Assisted Planning and Execution System

    PubMed Central

    Gordon, Chad R.; Murphy, Ryan J.; Coon, Devin; Basafa, Ehsan; Otake, Yoshito; Al Rakan, Mohammed; Rada, Erin; Susarla, Sriniras; Swanson, Edward; Fishman, Elliot; Santiago, Gabriel; Brandacher, Gerald; Liacouras, Peter; Grant, Gerald; Armand, Mehran

    2014-01-01

    Introduction Facial transplantation represents one of the most complicated scenarios in craniofacial surgery because of skeletal, aesthetic, and dental discrepancies between donor and recipient. However, standard off-the-shelf vendor computer-assisted surgery systems may not provide custom features to mitigate the increased complexity of this particular procedure. We propose to develop a computer-assisted surgery solution customized for preoperative planning, intraoperative navigation including cutting guides, and dynamic, instantaneous feedback of cephalometric measurements/angles as needed for facial transplantation. Methods We developed the Computer-Assisted Planning and Execution (CAPE) workstation to assist with planning and execution of facial transplantation. Preoperative maxillofacial computed tomography (CT) scans were obtained on 4 size-mismatched miniature swine encompassing 2 live face-jaw-teeth transplants. The system was tested in a laboratory setting using plastic models of mismatched swine, after which the system was used in 2 live swine transplants. Postoperative CT imaging was obtained and compared with the preoperative plan and intraoperative measures from the CAPE workstation for both transplants. Results Plastic model tests familiarized the team with the CAPE workstation and identified several defects in the workflow. Live swine surgeries demonstrated utility of the CAPE system in the operating room, showing submillimeter registration error of 0.6 ± 0.24 mm and promising qualitative comparisons between intraoperative data and postoperative CT imaging. Conclusions The initial development of the CAPE workstation demonstrated integration of computer planning and intraoperative navigation for facial transplantation are possible with submillimeter accuracy. This approach can potentially improve preoperative planning, allowing ideal donor-recipient matching despite significant size mismatch, and accurate surgical execution. PMID:24406592

  19. Preliminary development of a workstation for craniomaxillofacial surgical procedures: introducing a computer-assisted planning and execution system.

    PubMed

    Gordon, Chad R; Murphy, Ryan J; Coon, Devin; Basafa, Ehsan; Otake, Yoshito; Al Rakan, Mohammed; Rada, Erin; Susarla, Srinivas; Susarla, Sriniras; Swanson, Edward; Fishman, Elliot; Santiago, Gabriel; Brandacher, Gerald; Liacouras, Peter; Grant, Gerald; Armand, Mehran

    2014-01-01

    Facial transplantation represents one of the most complicated scenarios in craniofacial surgery because of skeletal, aesthetic, and dental discrepancies between donor and recipient. However, standard off-the-shelf vendor computer-assisted surgery systems may not provide custom features to mitigate the increased complexity of this particular procedure. We propose to develop a computer-assisted surgery solution customized for preoperative planning, intraoperative navigation including cutting guides, and dynamic, instantaneous feedback of cephalometric measurements/angles as needed for facial transplantation and other related craniomaxillofacial procedures. We developed the Computer-Assisted Planning and Execution (CAPE) workstation to assist with planning and execution of facial transplantation. Preoperative maxillofacial computed tomography (CT) scans were obtained on 4 size-mismatched miniature swine encompassing 2 live face-jaw-teeth transplants. The system was tested in a laboratory setting using plastic models of mismatched swine, after which the system was used in 2 live swine transplants. Postoperative CT imaging was obtained and compared with the preoperative plan and intraoperative measures from the CAPE workstation for both transplants. Plastic model tests familiarized the team with the CAPE workstation and identified several defects in the workflow. Live swine surgeries demonstrated utility of the CAPE system in the operating room, showing submillimeter registration error of 0.6 ± 0.24 mm and promising qualitative comparisons between intraoperative data and postoperative CT imaging. The initial development of the CAPE workstation demonstrated that integration of computer planning and intraoperative navigation for facial transplantation are possible with submillimeter accuracy. This approach can potentially improve preoperative planning, allowing ideal donor-recipient matching despite significant size mismatch, and accurate surgical execution for numerous

  20. Evaluation of Extraction Site Dimensions and Density Using Computed Tomography Treated With Different Graft Materials: A Preliminary Study.

    PubMed

    Cavdar, Filiz Hyusein; Keceli, Huseyin Gencay; Hatipoglu, Hasan; Demiralp, Burak; Caglayan, Feriha

    2017-04-01

    The preliminary human study was designed to evaluate extraction site changes using CT after socket preservation (SP) with different materials. Fifty-two sockets from 17 Turkish individuals (8 women and 9 men; mean age 44.70 ± 9.99 years) localized at the maxillary anterior area were treated with demineralized bone matrix + collagen membrane (CM) (N = 14), hydroxyapatite bone substitute (HBS) + CM (N = 14), CM (N = 13), or left empty (N = 11). CT scans were taken 10 and 120 days after the procedure. Horizontal and vertical socket dimensions and Hounsfield unit (HU) values were evaluated. First 3 groups showed a significant horizontal decrease from day 10 to 120. No significant change was detected in vertical socket dimension. For both horizontal and vertical, no intergroup difference was detected at days 10 and 120. At days 10 and 120, HU values in HBS + CM group were significantly higher compared with others. Apical and coronal HU values were not different at any period. Even if it did not provide better socket dimensions, HBS + CM treatment brought higher tissue density and thus, can be recommended to increase the bone quality and implant success after SP in upper anterior area.

  1. An analysis of Space Shuttle countdown activities: Preliminaries to a computational model of the NASA Test Director

    NASA Technical Reports Server (NTRS)

    John, Bonnie E.; Remington, Roger W.; Steier, David M.

    1991-01-01

    Before all systems are go just prior to the launch of a space shuttle, thousands of operations and tests have been performed to ensure that all shuttle and support subsystems are operational and ready for launch. These steps, which range from activating the orbiter's flight computers to removing the launch pad from the itinerary of the NASA tour buses, are carried out by launch team members at various locations and with highly specialized fields of expertise. The liability for coordinating these diverse activities rests with the NASA Test Director (NTD) at NASA-Kennedy. The behavior is being studied of the NTD with the goal of building a detailed computational model of that behavior; the results of that analysis to date are given. The NTD's performance is described in detail, as a team member who must coordinate a complex task through efficient audio communication, as well as an individual taking notes and consulting manuals. A model of the routine cognitive skill used by the NTD to follow the launch countdown procedure manual was implemented using the Soar cognitive architecture. Several examples are given of how such a model could aid in evaluating proposed computer support systems.

  2. Comparison of conventional ultrasonography and ultrasonography-computed tomography fusion imaging for target identification using digital/real hybrid phantoms: a preliminary study.

    PubMed

    Soyama, Takeshi; Sakuhara, Yusuke; Kudo, Kohsuke; Abo, Daisuke; Wang, Jeff; Ito, Yoichi M; Hasegawa, Yu; Shirato, Hiroki

    2016-07-01

    This preliminary study compared ultrasonography-computed tomography (US-CT) fusion imaging and conventional ultrasonography (US) for accuracy and time required for target identification using a combination of real phantoms and sets of digitally modified computed tomography (CT) images (digital/real hybrid phantoms). In this randomized prospective study, 27 spheres visible on B-mode US were placed at depths of 3.5, 8.5, and 13.5 cm (nine spheres each). All 27 spheres were digitally erased from the CT images, and a radiopaque sphere was digitally placed at each of the 27 locations to create 27 different sets of CT images. Twenty clinicians were instructed to identify the sphere target using US alone and fusion imaging. The accuracy of target identification of the two methods was compared using McNemar's test. The mean time required for target identification and error distances were compared using paired t tests. At all three depths, target identification was more accurate and the mean time required for target identification was significantly less with US-CT fusion imaging than with US alone, and the mean error distances were also shorter with US-CT fusion imaging. US-CT fusion imaging was superior to US alone in terms of accurate and rapid identification of target lesions.

  3. Design of a Tablet Computer App for Facilitation of a Molecular Blood Culture Test in Clinical Microbiology and Preliminary Usability Evaluation

    PubMed Central

    Pape-Haugaard, Louise; Meltzer, Michelle C; Fuchs, Martin; Schønheyder, Henrik C; Hejlesen, Ole

    2016-01-01

    Background User mobility is an important aspect of the development of clinical information systems for health care professionals. Mobile phones and tablet computers have obtained widespread use by health care professionals, offering an opportunity for supporting the access to patient information through specialized applications (apps) while supporting the mobility of the users. The use of apps for mobile phones and tablet computers may support workflow of complex tasks, for example, molecular-based diagnostic tests in clinical microbiology. Multiplex Blood Culture Test (MuxBCT) is a molecular-based diagnostic test used for rapid identification of pathogens in positive blood cultures. To facilitate the workflow of the MuxBCT, a specialized tablet computer app was developed as an accessory to the diagnostic test. The app aims to reduce the complexity of the test by step-by-step guidance of microscopy and to assist users in reaching an exact bacterial or fungal diagnosis based on blood specimen observations and controls. Additionally, the app allows for entry of test results, and communication thereof to the laboratory information system (LIS). Objective The objective of the study was to describe the design considerations of the MuxBCT app and the results of a preliminary usability evaluation. Methods The MuxBCT tablet app was developed and set up for use in a clinical microbiology laboratory. A near-live simulation study was conducted in the clinical microbiology laboratory to evaluate the usability of the MuxBCT app. The study was designed to achieve a high degree of realism as participants carried out a scenario representing the context of use for the MuxBCT app. As the MuxBCT was under development, the scenario involved the use of molecular blood culture tests similar to the MuxBCT for identification of microorganisms from positive blood culture samples. The study participants were observed, and their interactions with the app were recorded. After the study, the

  4. Design of a Tablet Computer App for Facilitation of a Molecular Blood Culture Test in Clinical Microbiology and Preliminary Usability Evaluation.

    PubMed

    Samson, Lasse L; Pape-Haugaard, Louise; Meltzer, Michelle C; Fuchs, Martin; Schønheyder, Henrik C; Hejlesen, Ole

    2016-03-18

    User mobility is an important aspect of the development of clinical information systems for health care professionals. Mobile phones and tablet computers have obtained widespread use by health care professionals, offering an opportunity for supporting the access to patient information through specialized applications (apps) while supporting the mobility of the users. The use of apps for mobile phones and tablet computers may support workflow of complex tasks, for example, molecular-based diagnostic tests in clinical microbiology. Multiplex Blood Culture Test (MuxBCT) is a molecular-based diagnostic test used for rapid identification of pathogens in positive blood cultures. To facilitate the workflow of the MuxBCT, a specialized tablet computer app was developed as an accessory to the diagnostic test. The app aims to reduce the complexity of the test by step-by-step guidance of microscopy and to assist users in reaching an exact bacterial or fungal diagnosis based on blood specimen observations and controls. Additionally, the app allows for entry of test results, and communication thereof to the laboratory information system (LIS). The objective of the study was to describe the design considerations of the MuxBCT app and the results of a preliminary usability evaluation. The MuxBCT tablet app was developed and set up for use in a clinical microbiology laboratory. A near-live simulation study was conducted in the clinical microbiology laboratory to evaluate the usability of the MuxBCT app. The study was designed to achieve a high degree of realism as participants carried out a scenario representing the context of use for the MuxBCT app. As the MuxBCT was under development, the scenario involved the use of molecular blood culture tests similar to the MuxBCT for identification of microorganisms from positive blood culture samples. The study participants were observed, and their interactions with the app were recorded. After the study, the participants were debriefed to

  5. Design and preliminary evaluation of the FINGER rehabilitation robot: controlling challenge and quantifying finger individuation during musical computer game play

    PubMed Central

    2014-01-01

    Background This paper describes the design and preliminary testing of FINGER (Finger Individuating Grasp Exercise Robot), a device for assisting in finger rehabilitation after neurologic injury. We developed FINGER to assist stroke patients in moving their fingers individually in a naturalistic curling motion while playing a game similar to Guitar Hero®a. The goal was to make FINGER capable of assisting with motions where precise timing is important. Methods FINGER consists of a pair of stacked single degree-of-freedom 8-bar mechanisms, one for the index and one for the middle finger. Each 8-bar mechanism was designed to control the angle and position of the proximal phalanx and the position of the middle phalanx. Target positions for the mechanism optimization were determined from trajectory data collected from 7 healthy subjects using color-based motion capture. The resulting robotic device was built to accommodate multiple finger sizes and finger-to-finger widths. For initial evaluation, we asked individuals with a stroke (n = 16) and without impairment (n = 4) to play a game similar to Guitar Hero® while connected to FINGER. Results Precision design, low friction bearings, and separate high speed linear actuators allowed FINGER to individually actuate the fingers with a high bandwidth of control (−3 dB at approximately 8 Hz). During the tests, we were able to modulate the subject’s success rate at the game by automatically adjusting the controller gains of FINGER. We also used FINGER to measure subjects’ effort and finger individuation while playing the game. Conclusions Test results demonstrate the ability of FINGER to motivate subjects with an engaging game environment that challenges individuated control of the fingers, automatically control assistance levels, and quantify finger individuation after stroke. PMID:24495432

  6. Preliminary 3D computational analysis of the relationship between aortic displacement force and direction of endograft movement.

    PubMed

    Figueroa, C Alberto; Taylor, Charles A; Yeh, Victoria; Chiou, Allen J; Gorrepati, Madhu L; Zarins, Christopher K

    2010-06-01

    Endograft migration is usually described as a downward displacement of the endograft with respect to the renal arteries. However, change in endograft position is actually a complex process in three-dimensional (3D) space. Currently, there are no established techniques to define such positional changes over time. The purpose of this study is to determine whether the direction of aortic endograft movement as observed in follow-up computed tomography (CT) scans is related to the directional displacement force acting on the endograft. We quantitated the 3D positional change over time of five abdominal endografts by determining the endograft centroid at baseline (postoperative scan) and on follow-up CT scans. The time interval between CT scans for the 5 patients ranged from 8 months to 8 years. We then used 3D image segmentation and computational fluid dynamics (CFD) techniques to quantitate the pulsatile displacement force (in Newtons [N]) acting on the endografts in the postoperative configurations. Finally, we calculated a correlation metric between the direction of the displacement force vector and the endograft movement by computing the cosine of the angle of these two vectors. The average 3D movement of the endograft centroid was 18 mm (range, 9-29 mm) with greater movement in patients with longer follow-up times. In all cases, the movement of the endograft had significant components in all three spatial directions: Two of the endografts had the largest component of movement in the transverse direction, whereas three endografts had the largest component of movement in the axial direction. The magnitude and orientation of the endograft displacement force varied depending on aortic angulation and hemodynamic conditions. The average magnitude of displacement force for all endografts was 5.8 N (range, 3.7-9.5 N). The orientation of displacement force was in general perpendicular to the greatest curvature of the endograft. The average correlation metric, defined as the

  7. Computer simulations of comet- and asteroidlike bodies passing through the Venusian atmosphere: Preliminary results on atmospheric and ground shock effects

    NASA Technical Reports Server (NTRS)

    Roddy, D.; Hatfield, D.; Hassig, P.; Rosenblatt, M.; Soderblom, L.; Dejong, E.

    1992-01-01

    We have completed computer simulations that model shock effects in the venusian atmosphere caused during the passage of two cometlike bodies 100 m and 1000 m in diameter and an asteroidlike body 10 km in diameter. Our objective is to examine hypervelocity-generated shock effects in the venusian atmosphere for bodies of different types and sizes in order to understand the following: (1) their deceleration and depth of penetration through the atmosphere; and (2) the onset of possible ground-surface shock effects such as splotches, craters, and ejecta formations. The three bodies were chosen to include both a range of general conditions applicable to Venus as well as three specific cases of current interest. These calculations use a new multiphase computer code (DICE-MAZ) designed by California Research & Technology for shock-dynamics simulations in complex environments. The code was tested and calibrated in large-scale explosion, cratering, and ejecta research. It treats a wide range of different multiphase conditions, including material types (vapor, melt, solid), particle-size distributions, and shock-induced dynamic changes in velocities, pressures, temperatures (internal energies), densities, and other related parameters, all of which were recorded in our calculations.

  8. Changing Community Health Behaviors with a Health Promotion Computer Network: Preliminary Findings from Stanford Health-Net

    PubMed Central

    Robinson, Thomas N.; Walters, Paul A.

    1987-01-01

    Computer-based health education has been employed in many settings. However, data on resultant behavior change are lacking. A randomized, controlled, prospective study was performed to test the efficacy of Stanford Health-Net in changing community health behaviors. Graduate and undergraduate students (N=1003) were randomly assigned to treatment and control conditions. The treatment group received access to Health-Net, a health promotion computer network emphasizing specific self-care and preventive strategies. Over a four month intervention period, 26% of the treatment group used Health-Net an average of 6.4 times each (range 1 to 97). Users rated Health-Net favorably. The mean number of ambulatory medical visits decreesed 22.5% more in the treatment group than in the control group (P<.05), while hospitalizations did not differ significantly between groups. In addition, perceived self-efficacy for preventing the acquisition of a STD and herpes increased 577% (P<.05) and 261% (P<.01) more, respectively, in the treatment group than in the control group. These findings suggest that access to Stanford Health-Net can result in significant health behavior change. The advantages of the network approach make it a potential model for other communities.

  9. Pledget-Armed Sutures Affect the Haemodynamic Performance of Biologic Aortic Valve Substitutes: A Preliminary Experimental and Computational Study.

    PubMed

    Capelli, Claudio; Corsini, Chiara; Biscarini, Dario; Ruffini, Francesco; Migliavacca, Francesco; Kocher, Alfred; Laufer, Guenther; Taylor, Andrew M; Schievano, Silvia; Andreas, Martin; Burriesci, Gaetano; Rath, Claus

    2017-03-01

    Surgical aortic valve replacement is the most common procedure of choice for the treatment of severe aortic stenosis. Bioprosthetic valves are traditionally sewed-in the aortic root by means of pledget-armed sutures during open-heart surgery. Recently, novel bioprostheses which include a stent-based anchoring system have been introduced to allow rapid implantation, therefore reducing the duration and invasiveness of the intervention. Different effects on the hemodynamics were clinically reported associated with the two technologies. The aim of this study was therefore to investigate whether the differences in hemodynamic performances are an effect of different anchoring systems. Two commercially available bio-prosthetic aortic valves, one sewed-in with pledget-armed sutures and one rapid-deployment, were thus tested in this study by means of a combined approach of experimental and computational tools. In vitro experiments were performed to evaluate the overall hydrodynamic performance under identical standard conditions; computational fluid dynamics analyses were set-up to explore local flow variations due to different design of the anchoring system. The results showed how the performance of cardiac valve substitutes is negatively affected by the presence of pledget-armed sutures. These are causing flow disturbances, which in turn increase the mean pressure gradient and decrease the effective orifice area. The combined approach of experiments and numerical simulations can be effectively used to quantify the detailed relationship between local fluid-dynamics and overall performances associated with different valve technologies.

  10. Atomic-scale tomography: a 2020 vision.

    PubMed

    Kelly, Thomas F; Miller, Michael K; Rajan, Krishna; Ringer, Simon P

    2013-06-01

    Atomic-scale tomography (AST) is defined and its place in microscopy is considered. Arguments are made that AST, as defined, would be the ultimate microscopy. The available pathways for achieving AST are examined and we conclude that atom probe tomography (APT) may be a viable basis for AST on its own and that APT in conjunction with transmission electron microscopy is a likely path as well. Some possible configurations of instrumentation for achieving AST are described. The concept of metaimages is introduced where data from multiple techniques are melded to create synergies in a multidimensional data structure. When coupled with integrated computational materials engineering, structure-properties microscopy is envisioned. The implications of AST for science and technology are explored.

  11. A preliminary study of a cloud-computing model for chronic illness self-care support in an underdeveloped country

    PubMed Central

    Piette, John D.; Mendoza-Avelares, Milton O.; Ganser, Martha; Mohamed, Muhima; Marinec, Nicolle; Krishnan, Sheila

    2013-01-01

    Background Although interactive voice response (IVR) calls can be an effective tool for chronic disease management, many regions of the world lack the infrastructure to provide these services. Objective This study evaluated the feasibility and potential impact of an IVR program using a cloud-computing model to improve diabetes management in Honduras. Methods A single group, pre-post study was conducted between June and August 2010. The telecommunications infrastructure was maintained on a U.S. server, and calls were directed to patients’ cell phones using VoIP. Eighty-five diabetes patients in Honduras received weekly IVR disease management calls for six weeks, with automated follow-up emails to clinicians, and voicemail reports to family caregivers. Patients completed interviews at enrollment and a six week follow-up. Other measures included patients’ glycemic control (A1c) and data from the IVR calling system. Results 55% of participants completed the majority of their IVR calls and 33% completed 80% or more. Higher baseline blood pressures, greater diabetes burden, greater distance from the clinic, and better adherence were related to higher call completion rates. Nearly all participants (98%) reported that because of the program, they improved in aspects of diabetes management such as glycemic control (56%) or foot care (89%). Mean A1c’s decreased from 10.0% at baseline to 8.9% at follow-up (p<.01). Most participants (92%) said that if the service were available in their clinic they would use it again. Conclusions Cloud computing is a feasible strategy for providing IVR services globally. IVR self-care support may improve self-care and glycemic control for patients in under-developed countries. PMID:21565655

  12. Single vs Two-session Root Canal Treatment: A Preliminary Randomized Clinical Study using Cone Beam Computed Tomography.

    PubMed

    de Castro Rizzi-Maia, Claudia; Maia-Filho, Etevaldo M; Nelson-Filho, Paulo; Segato, Raquel Ab; de Queiroz, Alexandra M; Paula-Silva, Francisco Wg; da Silva Pereira, Sângela M; Borges, Alvaro H; da Silva, Léa Ab

    2016-07-01

    To compare root canal treatment of teeth with apical periodontitis (AP) in a single or two visits, using cone beam computed tomography (CBCT). Twenty-six pairs of teeth (13 patients) were assigned to two groups: Group single-session (GSS): Instrumentation and root canal filling in the same session; and group two-session (GTS): A calcium hydroxide intracanal medication (Calen(®) paste) was used for 14 days between two sessions. Cone beam computed tomography scans were obtained before and 12 months after treatment. The pre- and postoperative volume of the AP lesions was measured in mm(3). The percentages of volume reduction was compared using Student's t-test and the existence of significant difference between the groups for cases with ≤ 50% or > 50% lesion volume reduction was assessed by chi-squared test ratio likelihood test (α = 5%). The volume reduction was greater in GTS (79.25%) than GSS (68.35%), though without significant difference (p > 0.05). After 12 months, complete repair was not observed in any specimen. Lesion volume reduction > 50% was significantly greater with the use of an intracanal medication (p < 0.05). Twelve months posttreatment, CBCT did not show complete repair in any of the teeth, suggesting that this follow-up period is not sufficient for complete lesion regression. In both groups, similar AP lesion volume reduction was observed after 12 months, with a more advanced repair (> 50% volume reduction) in the teeth medicated with calcium hydroxide intracanal dressing. Calcium hydroxide intracanal dressing provided clinical evidence to indicate its use in teeth with apical periodontitis prior to definitive root canal filling.

  13. Guideline for minimizing radiation exposure during acquisition of coronary artery calcium scans with the use of multidetector computed tomography: a report by the Society for Atherosclerosis Imaging and Prevention Tomographic Imaging and Prevention Councils in collaboration with the Society of Cardiovascular Computed Tomography.

    PubMed

    Voros, Szilard; Rivera, Juan J; Berman, Daniel S; Blankstein, Ron; Budoff, Matthew J; Cury, Ricardo C; Desai, Milind Y; Dey, Damini; Halliburton, Sandra S; Hecht, Harvey S; Nasir, Khurram; Santos, Raul D; Shapiro, Michael D; Taylor, Allen J; Valeti, Uma S; Young, Phillip M; Weissman, Gaby

    2011-01-01

    Coronary artery calcium (CAC) scanning is an important tool for risk stratification in intermediate-risk, asymptomatic subjects without previous coronary disease. However, the clinical benefit of improved risk prediction needs to be balanced against the risk of the use of ionizing radiation. Although there is increasing emphasis on the need to obtain CAC scans at low-radiation exposure to the patient, very few practical documents exist to aid laboratories and health care professionals on how to obtain such low-radiation scans. The Tomographic Imaging Council of the Society for Atherosclerosis Imaging and Prevention, in collaboration with the Prevention Council and the Society of Cardiovascular Computed Tomography, created a task force and writing group to generate a practical document to address parameters that can be influenced by careful attention to image acquisition. Patient selection for CAC scanning should be based on national guidelines. It is recommended that laboratories performing CAC examinations monitor radiation exposure (dose-length-product [DLP]) and effective radiation dose (E) in all patients. DLP should be <200 mGy × cm; E should average 1.0-1.5 mSv and should be <3.0 mSv. On most scanner platforms, CAC imaging should be performed in an axial mode with prospective electrocardiographic triggering, using tube voltage of 120 kVp. Tube current should be carefully selected on the basis of patient size, potentially using chest lateral width measured on the topogram. Scan length should be limited for the coverage of the heart only. When patients and imaging parameters are selected appropriately, CAC scanning can be performed with low levels of radiation exposure.

  14. Positron Emission Tomography: A Basic Analysis

    NASA Astrophysics Data System (ADS)

    Kerbacher, M. E.; Deaton, J. W.; Phinney, L. C.; Mitchell, L. J.; Duggan, J. L.

    2007-10-01

    Positron Emission Tomography is useful in detecting biological abnormalities. The technique involves attaching radiotracers to a material used inside the body, in many cases glucose. Glucose is absorbed most readily in areas of unusual cell growth or uptake of nutrients so through natural processes the treated glucose highlights regions of tumors and other degenerative disorders such as Alzheimer's disease. The higher the concentration of isotopes, the more dynamic the area. Isotopes commonly used as tracers are 11C, 18F, 13N, and 15O due to their easy production and short half-lives. Once the tracers have saturated an area of tissue they are detected using coincidence detectors collinear with individual isotopes. As the isotope decays it emits a positron which, upon annihilating an electron, produces two oppositely directioned gamma rays. The PET machine consists of several pairs of detectors, each 180 degrees from their partner detector. When the oppositely positioned detectors are collinear with the area of the isotope, a computer registers the location of the isotope and can compile an image of the activity of the highlighted area based on the position and strength of the isotopes.

  15. Preliminary Investigations of Creep Strain of Neogene Clay from Warsaw in Drained Triaxial Tests Assisted by Computed Microtomography

    NASA Astrophysics Data System (ADS)

    Kaczmarek, Łukasz Dominik; Dobak, Paweł Józef; Kiełbasiński, Kamil

    2017-06-01

    The study concerns soil creep deformation in multistage triaxial stress tests under drained conditions. High resolution X-ray computed microtomography (XμCT) was involved in structure recognition before and after triaxial tests. Undisturbed Neogene clay samples, which are widespread in central Poland, were used in this study. XμCT was used to identify representative sample series and informed the detection and rejection of unreliable ones. Maximum deviatoric stress for in situ stress confining condition was equal 95.1 kPa. This result helped in the design of further multistage investigations. The study identified the rheological strain course, which can be broken down into three characterizations: decreasing creep strain rate, transitional constant creep velocity, and accelerating creep deformation. The study found that due to multistage creep loading, the samples were strengthened. Furthermore, there is a visibly "brittle" character of failure, which may be the consequence of the microstructure transformation as a function of time as well as collapse of voids. Due to the glacial tectonic history of the analyzed samples, the reactivation of microcracks might also serve as an explanation. The number of the various sizes of shear planes after failure is confirmed by XμCT overexposure.

  16. Understanding the relationship between image quality and motion velocity in gated computed tomography: preliminary work for 4-dimensional musculoskeletal imaging.

    PubMed

    Tay, Shian Chao; Primak, Andrew N; Fletcher, Joel G; Schmidt, Bernhard; An, Kai-Nan; McCollough, Cynthia H

    2008-01-01

    To study the effect of motion velocity on image quality to determine the requirements for 4-dimensional (4D; ie, 3D + time) musculoskeletal computed tomographic (CT) imaging. A phantom with resolution targets in both axial (x-y) and coronal (x-z) planes was attached to a motion device and scanned with 64-slice CT using a retrospectively gated CT protocol with pitch values of 0.1 and 0.2. Data were acquired with the phantom at rest and while moving periodically along the x axis at several velocities. Spatial resolution and motion artifacts were assessed both for the axial and coronal targets. A linear relationship was found between motion artifact severity and phantom velocity. Spatial resolution was better preserved in the coronal target. However, coronal images displayed banding artifacts, with band displacements being linearly related to motion velocity. The 4D CT imaging of periodically moving objects with velocities up to 20 mm/s is feasible using a pitch value of 0.1 and a motion frequency of 30 cycles per minute.

  17. Preliminary evaluation of the dosimetric accuracy of cone-beam computed tomography for cases with respiratory motion

    NASA Astrophysics Data System (ADS)

    Kim, Dong Wook; Bae, Sunhyun; Chung, Weon Kuu; Lee, Yoonhee

    2014-04-01

    Cone-beam computed tomography (CBCT) images are currently used for patient positioning and adaptive dose calculation; however, the degree of CBCT uncertainty in cases of respiratory motion remains an interesting issue. This study evaluated the uncertainty of CBCT-based dose calculations for a moving target. Using a phantom, we estimated differences in the geometries and the Hounsfield units (HU) between CT and CBCT. The calculated dose distributions based on CT and CBCT images were also compared using a radiation treatment planning system, and the comparison included cases with respiratory motion. The geometrical uncertainties of the CT and the CBCT images were less than 0.15 cm. The HU differences between CT and CBCT images for standard-dose-head, high-quality-head, normal-pelvis, and low-dose-thorax modes were 31, 36, 23, and 33 HU, respectively. The gamma (3%, 0.3 cm)-dose distribution between CT and CBCT was greater than 1 in 99% of the area. The gamma-dose distribution between CT and CBCT during respiratory motion was also greater than 1 in 99% of the area. The uncertainty of the CBCT-based dose calculation was evaluated for cases with respiratory motion. In conclusion, image distortion due to motion did not significantly influence dosimetric parameters.

  18. Is micro-computed tomography useful for wear assessment of ceramic femoral heads? A preliminary evaluation of volume measurements.

    PubMed

    Parrilli, Annapaola; Falcioni, Stefano; Fini, Milena; Affatato, Saverio

    2016-11-02

    Wear associated with hip components represents the main clinical problem in these patients, and it is important to develop new techniques for more accurate measurements of that wear. Currently, the gravimetric method is the gold standard for assessing mass measurements in preclinical evaluations. However, this method does not give other information such as volumetric loss or surface deviation. This work aimed to develop and validate a new technique to quantify ceramic volume loss from in vitro experiments using micro-computed tomography (micro-CT). An alumina (BIOLOX® forte) femoral head (Ø = 28 mm) was used. Mass and volume loss were approached by gravimetric method (using a four decimal place digital microbalance) and by using Skyscan 1176 microtomographic system, respectively. Standard error and coefficient of variance of both gravimetric and experimental groups demonstrated the reliability of the micro-CT analysis technique. In conclusion, the findings of the present study suggest that this new protocol could be considered an important tool for wear assessment and that we have found a reliable metrological protocol for volumetric analysis of ceramic femoral head prostheses, demonstrating that the micro-CT technique can be an important tool for wear assessment.

  19. Fluorine-18-fluorodeoxyglucose positron emission tomography/computed tomography imaging in pyogenic and tuberculous spondylitis: preliminary study.

    PubMed

    Lee, In Sook; Lee, Jung Sub; Kim, Seong-Jang; Jun, Sungmin; Suh, Keun Tak

    2009-01-01

    The purpose of this study was to compare the effectiveness of positron emission tomography (PET)/computed tomography (CT) in distinguishing between tuberculous and pyogenic spondylitis with that of magnetic resonance imaging (MRI). Twenty-two consecutive patients confirmed to have tuberculous or pyogenic spondylitis were examined with both MRI and dual-time point PET/CT. The serum C-reactive protein (CRP) level was measured. The early and delayed PET/CT data were analyzed using the standardized uptake value (SUV). The radiologists scored the MRI findings and differentiated between tuberculous and pyogenic spondylitis. Each MRI result and CRP value was compared with the SUVs of PET/CT. The reviewers identified tuberculous spondylitis (n = 11) on MRI, with a sensitivity, specificity, and positive predictive values of 90%, 100%, and 100%, respectively. For pyogenic spondylitis (n = 11), the corresponding values were 100%, 90%, and 92%, respectively. There was a significant difference in the maximum SUVs of the early phase between tuberculous and pyogenic spondylitis (P = 0.028). Magnetic resonance imaging was superior to PET/CT in differentiating between tuberculous and pyogenic spondylitis (P = 0.043). A comparison of the maximum SUVs of the early phase and CRP values revealed a correlation coefficient of 0.581 (P = 0.006). The maximum SUVs of early-phase PET/CT may be complementary to MRI for differentiating pyogenic and tuberculous spondylitis and reflecting the activity of infectious spondylitis.

  20. The use of non-contrast computed tomography and color Doppler ultrasound in the characterization of urinary stones - preliminary results

    PubMed Central

    Bulakçı, Mesut; Tefik, Tzevat; Akbulut, Fatih; Örmeci, Mehmet Tolgahan; Beşe, Caner; Şanlı, Öner; Oktar, Tayfun; Salmaslıoğlu, Artür

    2015-01-01

    Objective To investigate the role of density value in computed tomography (CT) and twinkling artifact observed in color Doppler analysis for the prediction of the mineral composition of urinary stones. Material and methods A total of 42 patients who were operated via percutaneous or endoscopic means and had undergone abdominal non-contrast CT and color Doppler ultrasonography examinations were included in the study. X-ray diffraction method was utilized to analyze a total of 86 stones, and the correlations between calculated density values and twinkling intensities with stone types were investigated for each stone. Results Analyses of extracted stones revealed the presence of 40 calcium oxalate monohydrate, 12 calcium oxalate dihydrate, 9 uric acid, 11 calcium phosphate, and 14 cystine stones. The density values were calculated as 1499±269 Hounsfield Units (HU) for calcium oxalate monohydrate, 1505±221 HU for calcium oxalate dihydrate, 348±67 HU for uric acid, 1106±219 HU for calcium phosphate, and 563±115 HU for cystine stones. The artifact intensities were determined as grade 0 in 15, grade 1 in 32, grade 2 in 24, and grade 3 in 15 stones. Conclusion In case the density value of the stone is measured below 780 HU and grade 3 artifact intensity is determined, it can be inferred that the mineral composition of the stone tends to be cystine. PMID:26623143

  1. Preliminary Clinical Application of Removable Partial Denture Frameworks Fabricated Using Computer-Aided Design and Rapid Prototyping Techniques.

    PubMed

    Ye, Hongqiang; Ning, Jing; Li, Man; Niu, Li; Yang, Jian; Sun, Yuchun; Zhou, Yongsheng

    The aim of this study was to explore the application of computer-aided design and rapid prototyping (CAD/RP) for removable partial denture (RPD) frameworks and evaluate the fitness of the technique for clinical application. Three-dimensional (3D) images of dentition defects were obtained using a lab scanner. The RPD frameworks were designed using commercial dental software and manufactured using selective laser melting (SLM). A total of 15 cases of RPD prostheses were selected, wherein each patient received two types of RPD frameworks, prepared by CAD/RP and investment casting. Primary evaluation of the CAD/RP framework was performed by visual inspection. The gap between the occlusal rest and the relevant rest seat was then replaced using silicone, and the specimens were observed and measured. Paired t test was used to compare the average thickness and distributed thickness between the CAD/RP and investment casting frameworks. Analysis of variance test was used to compare the difference in thickness among different zones. The RPD framework was designed and directly manufactured using the SLM technique. CAD/RP frameworks may meet the clinical requirements with satisfactory retention and stability and no undesired rotation. Although the average gap between the occlusal rest and the corresponding rest seat of the CAD/RP frameworks was slightly larger than that of the investment casting frameworks (P < .05), it was acceptable for clinical application. RPD frameworks can be designed and fabricated directly using digital techniques with acceptable results in clinical application.

  2. Evaluation of urinary stones ex vivo with micro-computed tomography: preliminary results of an investigational technique.

    PubMed

    Huri, Emre; Tatar, Ilkan; Germiyanoglu, Cankon; Karakan, Tolga; Celik, Hakan Hamdi; Ersoy, Orkun

    2011-01-01

    To evaluate the ultrastructural features of the urinary stones removed with endoscopic stone surgery, using micro computed tomography (micro-CT). Patients who had endoscopic surgery for renal or ureteral stones removal were included in this study. After surgery, the stones were classified into three groups and investigated with Skyscan 1174 micro-CT. Group I underwent percutaneous nephrolithotomy (PNL) with ultrasonic lithotripsy; group II had ureteroscopic stone surgery (USS) with pneumatic lithotripsy; and group III (the control group) had stone removal with USS or PNL without lithotripsy. Stone homogeneity, voids, and the internal structure of the stones were evaluated. Chi-square test was used to evaluate the difference statistically. P values less than .05 were considered statistically significant. A total of 24 "calcium oxalate monohydrate" stones from 24 patients were scanned with micro-CT. Stones treated with ultrasonic lithotripsy (group I) were more fragile, fragmented, and cracked than those treated with the pneumatic lithotripsy (group II; P = .01). Stones in group II were more homogeneous and smooth than those in group I and resembled those of the control group (P = .02). Homogeneous, non-fragile stones and heterogeneous, fragile calculi were seen in all groups. The stone fragility could be confirmed by micro-CT investigation. Ultrasonic lithotripters increase the stone fragility, which is demonstrated with increased heterogeneity by micro-CT.

  3. Preliminary cone-beam computed tomography study evaluating dental and skeletal changes after treatment with a mandibular Schwarz appliance.

    PubMed

    Tai, Kiyoshi; Hotokezaka, Hitoshi; Park, Jae Hyun; Tai, Hisako; Miyajima, Kuniaki; Choi, Matthew; Kai, Lisa M; Mishima, Katsuaki

    2010-09-01

    The purpose of this study was to evaluate the efficacy of the Schwarz appliance with a new method of superimposing detailed cone-beam computed tomography (CBCT) images. The subjects were 28 patients with Angle Class I molar relationships and crowding; they were randomly divided into 2 groups: 14 expanded and 14 nonexpanded patients. Three-dimensional Rugle CBCT software (Medic Engineering, Kyoto, Japan) was used to measure 10 reference points before treatment (T0) and during the retention period of approximately 9 months after 6 to 12 months of expansion (T1). Cephalometric and cast measurements were used to evaluate the treatments in both groups. Also, the mandibular widths of both groups were measured along an axial plane at 2 levels below the cementoenamel junction from a CBCT scan. Differences between the 2 groups at T0 and T1 were analyzed by using the Mann-Whitney U test. The dental arch (including tooth root apices) had expanded; however, alveolar bone expansion was only up to 2 mm below the cementoenamel junction. There was a statistically significant (P <0.05) difference between the groups in terms of crown, cementoenamel junction, root, and upper alveolar process. However, no significant (P >0.05) differences were observed in the interwidths of the mandibular body, zygomatic bones, condylar heads, or mandibular antegonial notches. In the mandibular cast measurements, arch crowding and arch perimeter showed statistically significant changes in the expanded group. The buccal mandibular width and lingual mandibular width values had significant changes as measured from a point 2 mm below the cementoenamel junction. The findings suggest that the Schwarz appliance primarily affected the dentoalveolar complex, but it had little effect on either the mandibular body or any associated structures. In addition, the molar center of rotation was observed to be below the root apex. 2010 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

  4. Preliminary assessment of facial soft tissue thickness utilizing three-dimensional computed tomography models of living individuals.

    PubMed

    Parks, Connie L; Richard, Adam H; Monson, Keith L

    2014-04-01

    Facial approximation is the technique of developing a representation of the face from the skull of an unknown individual. Facial approximation relies heavily on average craniofacial soft tissue depths. For more than a century, researchers have employed a broad array of tissue depth collection methodologies, a practice which has resulted in a lack of standardization in craniofacial soft tissue depth research. To combat such methodological inconsistencies, Stephan and Simpson 2008 [15] examined and synthesized a large number of previously published soft tissue depth studies. Their comprehensive meta-analysis produced a pooled dataset of averaged tissue depths and a simplified methodology, which the researchers suggest be utilized as a minimum standard protocol for future craniofacial soft tissue depth research. The authors of the present paper collected craniofacial soft tissue depths using three-dimensional models generated from computed tomography scans of living males and females of four self-identified ancestry groups from the United States ranging in age from 18 to 62 years. This paper assesses the differences between: (i) the pooled mean tissue depth values from the sample utilized in this paper and those published by Stephan 2012 [21] and (ii) the mean tissue depth values of two demographically similar subsets of the sample utilized in this paper and those published by Rhine and Moore 1984 [16]. Statistical test results indicate that the tissue depths collected from the sample evaluated in this paper are significantly and consistently larger than those published by Stephan 2012 [21]. Although a lack of published variance data by Rhine and Moore 1984 [16] precluded a direct statistical assessment, a substantive difference was also concluded. Further, the dataset presented in this study is representative of modern American adults and is, therefore, appropriate for use in constructing contemporary facial approximations.

  5. Biological characterization of the skin of shortfin mako shark Isurus oxyrinchus and preliminary study of the hydrodynamic behaviour through computational fluid dynamics.

    PubMed

    Díez, G; Soto, M; Blanco, J M

    2015-07-01

    This study characterized the morphology, density and orientation of the dermal denticles along the body of a shortfin mako shark Isurus oxyrinchus and identified the hydrodynamic parameters of its body through a computational fluid-dynamics model. The study showed a great variability in the morphology, size, shape, orientation and density of dermal denticles along the body of I. oxyrinchus. There was a significant higher density in dorsal and ventral areas of the body and their highest angular deviations were found in the lower part of the mouth and in the areas between the pre-caudal pit and the second dorsal and pelvic fins. A detailed three-dimensional geometry from a scanned body of a shark was carried out to evaluate the hydrodynamic properties such as drag coefficient, lift coefficient and superficial (skin) friction coefficient of the skin together with flow velocity field, according to different roughness coefficients simulating the effect of the dermal denticles. This preliminary approach contributed to detailed information of the denticle interactions. As the height of the denticles was increased, flow velocity and the effect of lift decreased whereas drag increased. The highest peaks of skin friction coefficient were observed around the pectoral fins.

  6. On-line computer system to minimize laser injuries during surgery: preliminary system layout and proposal of the key features.

    PubMed

    Canestri, F

    1999-01-01

    The aim of this paper is to investigate some new user interface ideas and related application packages which aim to improve the degree of safety in an operating room during surgical operations in which an invasive laser beam is deployed. The overall value of the proposition is that a means is provided which ensures the successful completion of the surgical case while minimizing the risk of thermal and mechanical injuries to healthy tissues adjacent to the surgical field. According to surgeons operating with a variety of CO2 lasers available at both the National Cancer Institute in Milan, Italy, and the Sackler School of Medicine, Tel Aviv University, Israel, each laser device presents different cutting and coagulation properties. In order to identify which 'ideal' procedure might corroborate the subjective impression of each surgeon and also to provide one common tool to ensure procedures with a high level of safety, the author has worked for several months with surgeons and technicians of both Institutions to define the general design of a new on-line surgical operation planning and design system to be used during the pre-operative briefing activities and also as a consultation tool during operation. This software package will be developed and tested on both 'C' and FORTRAN compilers running on a commercially available PC which is driving a continuous wave (CW) CO2 laser device via its Instrument Bus interface. The present proposal describes the details of a software package called LCA (Laser-beam Controller and Adviser) which performs several controls in parallel on the key output parameters of a laser beam device during its utilization in delicate surgical operations. The required performances of this device needed during a given surgical operation are pre-simulated and compared against the well-known safety limits, which are stored in the computer's mass storage. If the surgeon's decision about the laser device set-up are considered to be too close to the

  7. [Preliminary application of kilo-volt cone-beam computed tomography to intensity-modulated radiotherapy of nasopharyngeal carcinoma].

    PubMed

    Wang, Jin; Xu, Feng; Bai, Sen; Zhang, Hong; Zhong, Ren-Ming; Li, Yan; Li, Xiao-Yu

    2008-07-01

    The intensity-modulated radiotherapy (IMRT) with its highly conformed dose distribution to nasopharyngeal cancer (NPC) and the surrounding critical organs is being accepted increasingly in clinical practice. Due to the steep dose fall-offs of IMRT at the target margin, precise patient positioning and verification are required. This study was to evaluate the role of kilo-volt cone-beam computed tomography (kV-CBCT) in guiding the accurate positioning of IMRT for NPC. kV-CBCT was performed on 22 NPC patients before radiotherapy. The acquired CBCT were co-registered with the planning CT for online set-up correction and offline planning target volume (PTV) analysis. The 22 patients received a total of 754 kV-CBCT scans. Among the 505 scans before couch correction, the detection rates of deviation of < or =2 mm were 76.4% in left-to-right (X) direction, 76.0% in superior-to-inferior (Y) direction, and 85.7% in anterior-to-posterior (Z) directionû among the 106 scans after correction, the detection rates were 97.2%, 97.2%, and 100% in X, Y and Z directions, respectivelyû among the 143 scans after treatment, the detection rates were 87.4%, 87.6%, and 90.0%, respectively. The overall setup errors in X, Y and Z directions were (-0.7+/-1.6) mm, (-0.7+/-1.8) mm and (-0.3+/-1.7) mm, respectively, before correctionû (-0.4+/-0.8) mm, (0.3+/-0.8) mm and (0.0+/-0.7) mm, respectively, after correctionû (0.2+/-1.2) mm, (0.3+/-1.3) mm and (0.1+/-1.1) mm, respectively, after treatment. The maximal PTV margin was 4.0 mm before correction and 2.1 mm after correction. kV-CBCT image-guided radiotherapy may improve the set-up precision of IMRT for NPC.

  8. Computer simulations of large asteroid impacts into oceanic and continental sites--preliminary results on atmospheric, cratering and ejecta dynamics

    USGS Publications Warehouse

    Roddy, D.J.; Schuster, S.H.; Rosenblatt, M.; Grant, L.B.; Hassig, P.J.; Kreyenhagen, K.N.

    1987-01-01

    Computer simulations have been completed that describe passage of a 10-km-diameter asteroid through the Earth's atmosphere and the subsequent cratering and ejecta dynamics caused by impact of the asteroid into both oceanic and continental sites. The asteroid was modeled as a spherical body moving vertically at 20 km/s with a kinetic energy of 2.6 ?? 1030 ergs (6.2 ?? 107 Mt ). Detailed material modeling of the asteroid, ocean, crustal units, sedimentary unit, and mantle included effects of strength and fracturing, generic asteroid and rock properties, porosity, saturation, lithostatic stresses, and geothermal contributions, each selected to simulate impact and geologic conditions that were as realistic as possible. Calculation of the passage of the asteroid through a U.S. Standard Atmosphere showed development of a strong bow shock wave followed by a highly shock compressed and heated air mass. Rapid expansion of this shocked air created a large low-density region that also expanded away from the impact area. Shock temperatures in air reached ???20,000 K near the surface of the uplifting crater rim and were as high as ???2000 K at more than 30 km range and 10 km altitude. Calculations to 30 s showed that the shock fronts in the air and in most of the expanding shocked air mass preceded the formation of the crater, ejecta, and rim uplift and did not interact with them. As cratering developed, uplifted rim and target material were ejected into the very low density, shock-heated air immediately above the forming crater, and complex interactions could be expected. Calculations of the impact events showed equally dramatic effects on the oceanic and continental targets through an interval of 120 s. Despite geologic differences in the targets, both cratering events developed comparable dynamic flow fields and by ???29 s had formed similar-sized transient craters ???39 km deep and ???62 km across. Transient-rim uplift of ocean and crust reached a maximum altitude of nearly

  9. Image fusion in dual energy computed tomography for detection of hypervascular liver hepatocellular carcinoma: phantom and preliminary studies.

    PubMed

    Kim, Kyung Su; Lee, Jeong Min; Kim, Seung Ho; Kim, Kyung Won; Kim, Soo Jin; Cho, Seung Hyun; Han, Joon Koo; Choi, Byung Ihn

    2010-03-01

    This study was designed to determine the optimal blending method and parameters to fuse computed tomography (CT) data sets with different energy levels in dual-energy CT (DECT) for the detection of hypervascular liver lesions. A liver agar phantom containing 8 conical tubes with various concentrations of contrast material, was scanned using a Somatom Definition Dual Source CT (DSCT; Siemens, Forchheim, Germany) scanner in the dual energy mode at different current settings. CT data sets obtained at voltage potentials of 80 kVp and 140 kVp were fused using the linear blending method and nonlinear method with different weighting factors (0.1, 0.3, 0.5, 0.7, and 0.9) and different parameters sets (A--lambda: 20, omega: 430; B--lambda: 20, omega: 70; C--lambda: 250, omega: 430; D--lambda: 250, omega: 70). In 20 patients with hepatocellular carcinomas, multiphasic liver CT scans including arterial, portal, and equilibrium phases were performed. DECT was used only during the arterial phase but a voltage potential of 120 kVp was used for both the portal and equilibrium phases. For quantitative analyses of the phantom and patient study, the contrast-to-noise ratio (CNR) of the lesion to liver on arterial phase images, was measured. For qualitative analysis of the CT images of the 20 study patients, 5 radiologists, each with a different level of clinical experience, independently assessed the 5 types of image sets regarding lesion conspicuity and overall image quality. This study followed the guidelines of our hospital's institutional review board, and patient informed written consent was not required. Statistical comparisons were made using repeated measures ANOVA with Bonferroni correction for multiple comparisons. For the phantom and patient studies, 2 linear images with weighting factors 0.5 and 0.7 and 2 nonlinear images with a wide width, showed a higher CNR of hyperattenuated lesions than a standard 0.3 weighting factor linear blended image (P < 0.05). For the patient

  10. Sci-Thur AM: Planning - 06: Planning target volume margin suitability in lung stereotactic body radiation therapy: A preliminary evaluation using cone-beam computed tomography.

    PubMed

    Mathew, L; Swaminath, A; Szabo, J; Wierzbicki, M

    2012-07-01

    Stereotactic body radiation therapy (SBRT) requires precise delivery of radiation to the target; intra- and inter-fraction lung tumour motion may adversely impact local tumour control. The purpose of this study was to retrospectively evaluate the impact of planning target volume (PTV) margin size on the coverage of the internal target volume (ITV) as localized in pre- and post-treatment cone-beam computed tomography (CBCT) images. Data from two patients undergoing SBRT were evaluated. For planning, free-breathing and 4DCT scans were performed, and used to contour the ITV. A 5mm margin was added to create the PTV. During treatment, 14 CBCTs were collected pre- and post-beam delivery. A data set comprising the average 4DCT intensities where available and treatment planning CT intensities for voxels that were beyond the field of view of the 4DCT was constructed. Registration of the combined planning image to each CBCT was performed using a deformable image registration algorithm. The transformations aligning the combined planning image with the CBCTs were applied to the planning ITV to obtain the treatment ITVs. For each CBCT, the fraction of treatment ITV within the PTV was determined using Boolean logic. This was repeated for various PTV margins ranging from 0 to 10 mm at 1mm intervals. The 3 and 5 mm PTV margins covered 95.1 ± 5.9% and 99.0 ± 2.0% of the ITV, respectively. Analysis of additional patients will be performed to confirm these preliminary results, which reinforce the use of a 5mm PTV margin for lung SBRT. © 2012 American Association of Physicists in Medicine.

  11. Prospective computer-assisted voice analysis for patients with early stage glottic cancer: A preliminary report of the functional result of laryngeal irradiation

    SciTech Connect

    Harrison, L.B.; Solomon, B.; Miller, S.; Fass, D.E.; Armstrong, J.; Sessions, R.B. )

    1990-07-01

    In January 1987 we began a prospective study aimed at evaluating objective parameters of vocal function for all patients treated with RT for early glottic cancer. All patients underwent vocal analysis using a voice analyzer interfaced with a computer. This allowed for the determination of percent voicing (%V) (normal = presence of phonation = 90-100%V). Other parameters such as breathiness and strain were also measured. Patients were recorded before RT, weekly during RT, and at set intervals after RT. There have been 25 patients studied. Eighteen (18) are evaluable at 9 months after treatment. All patients were male and ranged from 45-84 years old. Fourteen (14) and T1 lesions and received 66 GY/33 fractions to their larynx and 4 had T2 tumors and received 66-70 Gy/33-35 fractions. To date, all patients are locally controlled. Three distinct patterns of %V changes have been encountered. However, all patients demonstrated normal phonation pattern by 3 months after RT, and this is sustained at 9 months follow-up. In addition, 94% of patients have had significant decrease in breathiness after RT, which objectively documents diminished hoarseness. In 83%, breathiness is normal after RT. Most patients have had increased strain after RT, which documents increased vocal cord tension. However, strain remained within normal limits in 89%. Our preliminary analysis suggests that the majority of patients irradiated for early glottic cancer demonstrate a decrease in breathiness and an increase in strain after RT, and enjoy a resultant voice that has normal phonation maintained at 9 months after RT. Our data also demonstrate three distinct phonation patterns. Further follow-up will allow us to determine the prognostic significance, if any, of these patterns, and to continue to follow objective vocal parameters on larger numbers of patient.

  12. SUPER-RESOLUTION ULTRASOUND TOMOGRAPHY: A PRELIMINARY STUDY WITH A RING ARRAY

    SciTech Connect

    HUANG, LIANJIE; SIMONETTI, FRANCESCO; DURIC, NEBOJSA; RAMA, OLSI

    2007-01-18

    Ultrasound tomography attempts to retrieve the structure of an objective by exploiting the interaction of acoustic waves with the object. A fundamental limit of ultrasound tomography is that features cannot be resolved if they are spaced less than {lambda}/2 apart, where {lambda} is wavelength of the probing wave, regardless of the degree of accuracy of the measurements. Therefore, since the attenuation of the probing wave with propagation distance increases as {lambda} decreases, resolution has to be traded against imaging depth. Recently, it has been shown that the {lambda}/2 limit is a consequence of the Born approximation (implicit in the imaging algorithms currently employed) which neglects the distortion of the probing wavefield as it travels through the medium to be imaged. On the other hand, such a distortion, which is due to the multiple scattering phenomenon, can encode unlimited resolution in the radiating component of the scattered field. Previously, a resolution better than {lambda}/3 has been reported in these proceedings [F. Simonetti, pp. 126 (2006)] in the case of elastic wave probing. In this paper, they demonstrate experimentally a resolution better than {lambda}/4 for objects immersed in a water bth probed by means of a ring array which excites and detects pressure waves in a full view configuration.

  13. SU-E-I-74: Image-Matching Technique of Computed Tomography Images for Personal Identification: A Preliminary Study Using Anthropomorphic Chest Phantoms

    SciTech Connect

    Matsunobu, Y; Shiotsuki, K; Morishita, J

    2015-06-15

    Purpose: Fingerprints, dental impressions, and DNA are used to identify unidentified bodies in forensic medicine. Cranial Computed tomography (CT) images and/or dental radiographs are also used for identification. Radiological identification is important, particularly in the absence of comparative fingerprints, dental impressions, and DNA samples. The development of an automated radiological identification system for unidentified bodies is desirable. We investigated the potential usefulness of bone structure for matching chest CT images. Methods: CT images of three anthropomorphic chest phantoms were obtained on different days in various settings. One of the phantoms was assumed to be an unidentified body. The bone image and the bone image with soft tissue (BST image) were extracted from the CT images. To examine the usefulness of the bone image and/or the BST image, the similarities between the two-dimensional (2D) or threedimensional (3D) images of the same and different phantoms were evaluated in terms of the normalized cross-correlation value (NCC). Results: For the 2D and 3D BST images, the NCCs obtained from the same phantom assumed to be an unidentified body (2D, 0.99; 3D, 0.93) were higher than those for the different phantoms (2D, 0.95 and 0.91; 3D, 0.89 and 0.80). The NCCs for the same phantom (2D, 0.95; 3D, 0.88) were greater compared to those of the different phantoms (2D, 0.61 and 0.25; 3D, 0.23 and 0.10) for the bone image. The difference in the NCCs between the same and different phantoms tended to be larger for the bone images than for the BST images. These findings suggest that the image-matching technique is more useful when utilizing the bone image than when utilizing the BST image to identify different people. Conclusion: This preliminary study indicated that evaluating the similarity of bone structure in 2D and 3D images is potentially useful for identifying of an unidentified body.

  14. Flat panel detector-based cone beam computed tomography with a circle-plus-two-arcs data acquisition orbit: preliminary phantom study.

    PubMed

    Ning, Ruola; Tang, Xiangyang; Conover, David; Yu, Rongfeng

    2003-07-01

    Cone beam computed tomography (CBCT) has been investigated in the past two decades due to its potential advantages over a fan beam CT. These advantages include (a) great improvement in data acquisition efficiency, spatial resolution, and spatial resolution uniformity, (b) substantially better utilization of x-ray photons generated by the x-ray tube compared to a fan beam CT, and (c) significant advancement in clinical three-dimensional (3D) CT applications. However, most studies of CBCT in the past are focused on cone beam data acquisition theories and reconstruction algorithms. The recent development of x-ray flat panel detectors (FPD) has made CBCT imaging feasible and practical. This paper reports a newly built flat panel detector-based CBCT prototype scanner and presents the results of the preliminary evaluation of the prototype through a phantom study. The prototype consisted of an x-ray tube, a flat panel detector, a GE 8800 CT gantry, a patient table and a computer system. The prototype was constructed by modifying a GE 8800 CT gantry such that both a single-circle cone beam acquisition orbit and a circle-plus-two-arcs orbit can be achieved. With a circle-plus-two-arcs orbit, a complete set of cone beam projection data can be obtained, consisting of a set of circle projections and a set of arc projections. Using the prototype scanner, the set of circle projections were acquired by rotating the x-ray tube and the FPD together on the gantry, and the set of arc projections were obtained by tilting the gantry while the x-ray tube and detector were at the 12 and 6 o'clock positions, respectively. A filtered backprojection exact cone beam reconstruction algorithm based on a circle-plus-two-arcs orbit was used for cone beam reconstruction from both the circle and arc projections. The system was first characterized in terms of the linearity and dynamic range of the detector. Then the uniformity, spatial resolution and low contrast resolution were assessed using

  15. A Preliminary Investigation of Supplemental Computer-Assisted Reading Instruction on the Oral Reading Fluency and Comprehension of First-Grade African American Urban Students

    ERIC Educational Resources Information Center

    Gibson, Lenwood; Cartledge, Gwendolyn; Keyes, Starr E.

    2011-01-01

    This preliminary investigation examined the effects of a computerized supplemental reading program on the oral reading fluency, reading growth rates, and comprehension of 8 African American first graders. Participants were selected for this study according to scores within risk categories on the Dynamic Indicators of Basic Early Literacy Skills…

  16. Characterization of waste drums using nonintrusive active and passive computed tomography

    SciTech Connect

    Roberson, G.P.; Martz, H.E.; Decman, D.J.; Camp, D.C.; Azevedo, S.G.; Keto, E.R.

    1994-08-01

    We have developed a data acquisition scanner for gamma-ray nondestructive assay (NDA) active and passive computed tomography (A&PCT) along with associated computational techniques for image reconstruction, analysis, and display. We are using this scanner to acquire data sets of mock-waste drums at Lawrence Livermore National Laboratory (LLNIL). In this paper, we discuss some issues associated with gamma-ray spectroscopy assay, NDA imaging, describe the design and construction of an NDA drum scanner and report on code development for image reconstruction. We also present representative A&PCT assay results of well characterized mock-waste drums. These preliminary results suggest that A&PCT imaging can be used to produce accurate absolute assays of radioactivity in real-waste drums.

  17. Computer Assisted Instruction and Bibliographic Instruction: Preliminary Data on the Use of PLATO in the BI Program of the Humanities and Social Sciences Library, University of Alberta.

    ERIC Educational Resources Information Center

    Champion, Brian

    In response to requests from the University of Alberta Department of Computing Services for PLATO (Programmed Logic for Automatic Teaching Operations) applications in structured learning situations, a program for computer-assisted bibliographic instruction (BI) was developed. The program is divided into the following six units: (1) Introduction;…

  18. Differentiating small (≤1 cm) focal liver lesions as metastases or cysts by means of computed tomography: a case-study to illustrate a fuzzy logic-based method to assess the impact of diagnostic confidence on radiological diagnosis.

    PubMed

    Girometti, Rossano; Fabris, Francesco; Sgarro, Andrea; Zanella, Gloria; Pullini, Serena; Cereser, Lorenzo; Como, Giuseppe; Zuiani, Chiara; Bazzocchi, Massimo

    2014-01-01

    To quantify the impact of diagnostic confidence on radiological diagnosis with a fuzzy logic-based method. Twenty-two oncologic patients with 20 cysts and 30 metastases ≤1 cm in size found at 64-row computed tomography were included. Two readers (R1/R2) expressed diagnoses as a subjective level of confidence P(d) in malignancy within the interval [0,1] rather than on a "crisp" basis (malignant/benign); confidence in benignancy was 1 - p(d). When cross-tabulating data according to the standard of reference, 2 × 2 table cells resulted from the aggregation between p(d)/1 - p(d) and final diagnosis. We then assessed (i) readers diagnostic performance on a fuzzy and crisp basis; (ii) the "divergence" δ(F, C) (%) as a measure of how confidence impacted on crisp diagnosis. Diagnoses expressed with lower confidence increased fuzzy false positives compared to crisp ones (from 0 to 0.2 for R1; from 1 to 2.4 for R2). Crisp/fuzzy accuracy was 94.0%/93.6% (R1) and 94.0/91.6% (R2). δ(F, C) (%) was larger in the case of the less experienced reader (R2) (up to +7.95% for specificity). According to simulations, δ(F, C) (%) was negative/positive depending on the level of confidence in incorrect diagnoses. Fuzzy evaluation shows a measurable effect of uncertainty on radiological diagnoses.

  19. Differentiating Small (≤1 cm) Focal Liver Lesions as Metastases or Cysts by means of Computed Tomography: A Case-Study to Illustrate a Fuzzy Logic-Based Method to Assess the Impact of Diagnostic Confidence on Radiological Diagnosis

    PubMed Central

    Zanella, Gloria; Pullini, Serena; Como, Giuseppe; Bazzocchi, Massimo

    2014-01-01

    Purpose. To quantify the impact of diagnostic confidence on radiological diagnosis with a fuzzy logic-based method. Materials and Methods. Twenty-two oncologic patients with 20 cysts and 30 metastases ≤1 cm in size found at 64-row computed tomography were included. Two readers (R1/R2) expressed diagnoses as a subjective level of confidence P(d) in malignancy within the interval [0,1] rather than on a “crisp” basis (malignant/benign); confidence in benignancy was 1 − p(d). When cross-tabulating data according to the standard of reference, 2 × 2 table cells resulted from the aggregation between p(d)/1 − p(d) and final diagnosis. We then assessed (i) readers diagnostic performance on a fuzzy and crisp basis; (ii) the “divergence” δ(F, C) (%) as a measure of how confidence impacted on crisp diagnosis. Results. Diagnoses expressed with lower confidence increased fuzzy false positives compared to crisp ones (from 0 to 0.2 for R1; from 1 to 2.4 for R2). Crisp/fuzzy accuracy was 94.0%/93.6% (R1) and 94.0/91.6% (R2). δ(F, C) (%) was larger in the case of the less experienced reader (R2) (up to +7.95% for specificity). According to simulations, δ(F, C) (%) was negative/positive depending on the level of confidence in incorrect diagnoses. Conclusion. Fuzzy evaluation shows a measurable effect of uncertainty on radiological diagnoses. PMID:24587815

  20. Preliminary Results on Studying of Meteorites from Geological Museum of Kazan University by X-Ray Fluorescence and Computed X-Ray Tomography

    NASA Astrophysics Data System (ADS)

    Kuzina, D. M.; Nurgaliev, D. K.; Gareev, B. I.; Batalin, G. A.; Silantev, V. V.; Statsenko, E. O.

    2017-02-01

    Micro X-ray fluorescence and X-ray computed tomography used for studying meteorites (particularly chondrules and iron-nickel alloys) from Geological Museum (Kazan), their elemental composition, and distribution of these objects in the body of meteorite.

  1. Crosswell seismic reflection/diffraction tomography: A reservoir characterization application

    SciTech Connect

    Tura, M.A.C. . Dept. of Earth Sciences); Greaves, R.J. . Earth Resources Lab.); Beydoun, W.B. )

    1994-03-01

    A crosswell seismic experiment at the San Emidio oil field in Bakersfield, California, is carried out to evaluate crosswell reflection/diffraction tomography and image the interwell region to locate a possible pinchout zone. In this experiment, the two wells used are 2,500 ft (762 m) apart, and the zone to be imaged is 11,000 ft (3,350 m) to 13,000 ft (3,960 m) deep. With the considered distances, this experiment forms the first large scale reservoir characterization application of crosswell reflection/diffraction tomography. A subset of the intended data, formed of two common receiver gathers and one common shot gather, was collected at the San Emidio oil field. The cross-well data display a wide variety of wave modes including tube waves, singly and multiply reflected/diffracted waves, and refracted waves. The data are processed using frequency filters, median filters, and spatial muting filters to enhance the reflected/diffracted energy. With the encouraging results obtained from synthetic data, the ERBMI method, with the smooth background velocity model is used next to image the processed field data. Images obtained from the crosswell data show a good match with the reflected field in the zero-offset VSPs and with migrated surface seismic data. From the interpretation of these images, the potential of this crosswell seismic method for answering questions regarding reservoir continuity and existence of pinchout zones can be seen.

  2. ACCF/SCCT/ACR/AHA/ASE/ASNC/NASCI/SCAI/SCMR 2010 Appropriate Use Criteria for Cardiac Computed Tomography. A Report of the American College of Cardiology Foundation Appropriate Use Criteria Task Force, the Society of Cardiovascular Computed Tomography, the American College of Radiology, the American Heart Association, the American Society of Echocardiography, the American Society of Nuclear Cardiology, the North American Society for Cardiovascular Imaging, the Society for Cardiovascular Angiography and Interventions, and the Society for Cardiovascular Magnetic Resonance.

    PubMed

    Taylor, Allen J; Cerqueira, Manuel; Hodgson, John McB; Mark, Daniel; Min, James; O'Gara, Patrick; Rubin, Geoffrey D

    2010-01-01

    The American College of Cardiology Foundation (ACCF), along with key specialty and subspecialty societies, conducted an appropriate use review of common clinical scenarios where cardiac computed tomography (CCT) is frequently considered. The present document is an update to the original CCT/cardiac magnetic resonance (CMR) appropriateness criteria published in 2006, written to reflect changes in test utilization, to incorporate new clinical data, and to clarify CCT use where omissions or lack of clarity existed in the original criteria (1). The indications for this review were drawn from common applications or anticipated uses, as well as from current clinical practice guidelines. Ninety-three clinical scenarios were developed by a writing group and scored by a separate technical panel on a scale of 1 to 9 to designate appropriate use, inappropriate use, or uncertain use. In general, use of CCT angiography for diagnosis and risk assessment in patients with low or intermediate risk or pretest probability for coronary artery disease (CAD) was viewed favorably, whereas testing in high-risk patients, routine repeat testing, and general screening in certain clinical scenarios were viewed less favorably. Use of noncontrast computed tomography (CT) for calcium scoring was rated as appropriate within intermediate- and selected low-risk patients. Appropriate applications of CCT are also within the category of cardiac structural and functional evaluation. It is anticipated that these results will have an impact on physician decision making, performance, and reimbursement policy, and that they will help guide future research.

  3. ACCF/SCCT/ACR/AHA/ASE/ASNC/NASCI/SCAI/SCMR 2010 Appropriate Use Criteria for Cardiac Computed Tomography. A Report of the American College of Cardiology Foundation Appropriate Use Criteria Task Force, the Society of Cardiovascular Computed Tomography, the American College of Radiology, the American Heart Association, the American Society of Echocardiography, the American Society of Nuclear Cardiology, the North American Society for Cardiovascular Imaging, the Society for Cardiovascular Angiography and Interventions, and the Society for Cardiovascular Magnetic Resonance.

    PubMed

    Taylor, Allen J; Cerqueira, Manuel; Hodgson, John McB; Mark, Daniel; Min, James; O'Gara, Patrick; Rubin, Geoffrey D

    2010-11-23

    The American College of Cardiology Foundation, along with key specialty and subspecialty societies, conducted an appropriate use review of common clinical scenarios where cardiac computed tomography (CCT) is frequently considered. The present document is an update to the original CCT/cardiac magnetic resonance appropriateness criteria published in 2006, written to reflect changes in test utilization, to incorporate new clinical data, and to clarify CCT use where omissions or lack of clarity existed in the original criteria. The indications for this review were drawn from common applications or anticipated uses, as well as from current clinical practice guidelines. Ninety-three clinical scenarios were developed by a writing group and scored by a separate technical panel on a scale of 1 to 9 to designate appropriate use, inappropriate use, or uncertain use. In general, use of CCT angiography for diagnosis and risk assessment in patients with low or intermediate risk or pretest probability for coronary artery disease was viewed favorably, whereas testing in high-risk patients, routine repeat testing, and general screening in certain clinical scenarios were viewed less favorably. Use of noncontrast computed tomography for calcium scoring was rated as appropriate within intermediate- and selected low-risk patients. Appropriate applications of CCT are also within the category of cardiac structural and functional evaluation. It is anticipated that these results will have an impact on physician decision making, performance, and reimbursement policy, and that they will help guide future research.

  4. ACCF/SCCT/ACR/AHA/ASE/ASNC/NASCI/SCAI/SCMR 2010 appropriate use criteria for cardiac computed tomography. A report of the American College of Cardiology Foundation Appropriate Use Criteria Task Force, the Society of Cardiovascular Computed Tomography, the American College of Radiology, the American Heart Association, the American Society of Echocardiography, the American Society of Nuclear Cardiology, the North American Society for Cardiovascular Imaging, the Society for Cardiovascular Angiography and Interventions, and the Society for Cardiovascular Magnetic Resonance.

    PubMed

    Taylor, Allen J; Cerqueira, Manuel; Hodgson, John McB; Mark, Daniel; Min, James; O'Gara, Patrick; Rubin, Geoffrey D; Kramer, Christopher M; Berman, Daniel; Brown, Alan; Chaudhry, Farooq A; Cury, Ricardo C; Desai, Milind Y; Einstein, Andrew J; Gomes, Antoinette S; Harrington, Robert; Hoffmann, Udo; Khare, Rahul; Lesser, John; McGann, Christopher; Rosenberg, Alan; Schwartz, Robert; Shelton, Marc; Smetana, Gerald W; Smith, Sidney C

    2010-11-23

    The American College of Cardiology Foundation (ACCF), along with key specialty and subspecialty societies, conducted an appropriate use review of common clinical scenarios where cardiac computed tomography (CCT) is frequently considered. The present document is an update to the original CCT/cardiac magnetic resonance (CMR) appropriateness criteria published in 2006, written to reflect changes in test utilization, to incorporate new clinical data, and to clarify CCT use where omissions or lack of clarity existed in the original criteria (1). The indications for this review were drawn from common applications or anticipated uses, as well as from current clinical practice guidelines. Ninety-three clinical scenarios were developed by a writing group and scored by a separate technical panel on a scale of 1 to 9 to designate appropriate use, inappropriate use, or uncertain use. In general, use of CCT angiography for diagnosis and risk assessment in patients with low or intermediate risk or pretest probability for coronary artery disease (CAD) was viewed favorably, whereas testing in high-risk patients, routine repeat testing, and general screening in certain clinical scenarios were viewed less favorably. Use of noncontrast computed tomography (CT) for calcium scoring was rated as appropriate within intermediate- and selected low-risk patients. Appropriate applications of CCT are also within the category of cardiac structural and functional evaluation. It is anticipated that these results will have an impact on physician decision making, performance, and reimbursement policy, and that they will help guide future research.

  5. Effects of computer-based graphic organizers to solve one-step word problems for middle school students with mild intellectual disability: A preliminary study.

    PubMed

    Sheriff, Kelli A; Boon, Richard T

    2014-08-01

    The purpose of this study was to examine the effects of computer-based graphic organizers, using Kidspiration 3© software, to solve one-step word problems. Participants included three students with mild intellectual disability enrolled in a functional academic skills curriculum in a self-contained classroom. A multiple probe single-subject research design (Horner & Baer, 1978) was used to evaluate the effectiveness of computer-based graphic organizers to solving mathematical one-step word problems. During the baseline phase, the students completed a teacher-generated worksheet that consisted of nine functional word problems in a traditional format using a pencil, paper, and a calculator. In the intervention and maintenance phases, the students were instructed to complete the word problems using a computer-based graphic organizer. Results indicated that all three of the students improved in their ability to solve the one-step word problems using computer-based graphic organizers compared to traditional instructional practices. Limitations of the study and recommendations for future research directions are discussed.

  6. A Preliminary Investigation of the Benefits of Computer-Aided Instruction in Reading Decoding for Students with Autism Spectrum Disorder and Other Developmental Disabilities

    ERIC Educational Resources Information Center

    Hill, Doris Adams; Flores, Margaret M.

    2015-01-01

    For students who have limited expressive language skills, both verbally and in writing, it is difficult for a teacher to assess the acquisition of reading skills. The authors examined the effects of computer-aided instruction (CAI) on the early reading and reading comprehension skills of six students with autism spectrum disorder, and other…

  7. Evaluation of a Short-Term Computer-Assisted Training Programme for the Remediation of Attentional Deficits after Brain Injury: A Preliminary Study.

    ERIC Educational Resources Information Center

    Gauggel, S.; Niemann, T.

    1996-01-01

    This study evaluated a computer-assisted training program used by four patients (ages 40 to 53) who had attentional deficits caused by cerebrovascular accident and closed head injury. Patients demonstrated improvements in training tasks, attention, and visual memory, but no improvements in two verbal memory tests and a general intelligence test.…

  8. Oceanic pipeline computations

    SciTech Connect

    Marks, A.

    1980-01-01

    yechnical and economic feasibility, design, and construction of oil, gas, and two-phase oceanic pipelines systems are discussed. In addition, formulae, references, examples, and programmable calculator software (Hewlett-Packard-67) are given. The contents include: preliminary pipeline sizing; fluid characteristics; preliminary hydraulics; oceanographis; preliminary corridor selection; route selection; final pipeline design; hydraulic design; wall thickness selection; oceanographic design computations; stress analysis; and construction parameters. (JMT)

  9. An Overview of Preliminary Computational and Experimental Results for the Semi-Span Super-Sonic Transport (S4T) Wind-Tunnel Model

    NASA Technical Reports Server (NTRS)

    Silva, Walter A.; Perry, Boyd, III; Florance, James R.; Sanetrik, Mark D.; Wieseman, Carol D.; Stevens, William L.; Funk, Christie J.; Hur, Jiyoung; Christhilf, David M.; Coulson, David A.

    2011-01-01

    A summary of computational and experimental aeroelastic and aeroservoelastic (ASE) results for the Semi-Span Super-Sonic Transport (S4T) wind-tunnel model is presented. A broad range of analyses and multiple ASE wind-tunnel tests of the S4T have been performed in support of the ASE element in the Supersonics Program, part of NASA's Fundamental Aeronautics Program. The computational results to be presented include linear aeroelastic and ASE analyses, nonlinear aeroelastic analyses using an aeroelastic CFD code, and rapid aeroelastic analyses using CFD-based reduced-order models (ROMs). Experimental results from two closed-loop wind-tunnel tests performed at NASA Langley's Transonic Dynamics Tunnel (TDT) will be presented as well.

  10. Computer-enhanced interventions for drug use and HIV risk in the emergency room: preliminary results on psychological precursors of behavior change.

    PubMed

    Bonar, Erin E; Walton, Maureen A; Cunningham, Rebecca M; Chermack, Stephen T; Bohnert, Amy S B; Barry, Kristen L; Booth, Brenda M; Blow, Frederic C

    2014-01-01

    This article describes process data from a randomized controlled trial among 781 adults recruited in the emergency department who reported recent drug use and were randomized to: intervener-delivered brief intervention (IBI) assisted by computer, computerized BI (CBI), or enhanced usual care (EUC). Analyses examined differences between baseline and post-intervention on psychological constructs theoretically related to changes in drug use and HIV risk: importance, readiness, intention, help-seeking, and confidence. Compared to EUC, participants receiving the IBI significantly increased in confidence and intentions; CBI patients increased importance, readiness, confidence, and help-seeking. Both groups increased relative to the EUC in likelihood of condom use with regular partners. Examining BI components suggested that benefits of change and tools for change were associated with changes in psychological constructs. Delivering BIs targeting drug use and HIV risk using computers appears promising for implementation in healthcare settings. This trial is ongoing and future work will report behavioral outcomes.

  11. A web-based remote radiation treatment planning system using the remote desktop function of a computer operating system: a preliminary report.

    PubMed

    Suzuki, Keishiro; Hirasawa, Yukinori; Yaegashi, Yuji; Miyamoto, Hideki; Shirato, Hiroki

    2009-01-01

    We developed a web-based, remote radiation treatment planning system which allowed staff at an affiliated hospital to obtain support from a fully staffed central institution. Network security was based on a firewall and a virtual private network (VPN). Client computers were installed at a cancer centre, at a university hospital and at a staff home. We remotely operated the treatment planning computer using the Remote Desktop function built in to the Windows operating system. Except for the initial setup of the VPN router, no special knowledge was needed to operate the remote radiation treatment planning system. There was a time lag that seemed to depend on the volume of data traffic on the Internet, but it did not affect smooth operation. The initial cost and running cost of the system were reasonable.

  12. Can a numerically stable subgrid-scale model for turbulent flow computation be ideally accurate?: a preliminary theoretical study for the Gaussian filtered Navier-Stokes equations.

    PubMed

    Ida, Masato; Taniguchi, Nobuyuki

    2003-09-01

    This paper introduces a candidate for the origin of the numerical instabilities in large eddy simulation repeatedly observed in academic and practical industrial flow computations. Without resorting to any subgrid-scale modeling, but based on a simple assumption regarding the streamwise component of flow velocity, it is shown theoretically that in a channel-flow computation, the application of the Gaussian filtering to the incompressible Navier-Stokes equations yields a numerically unstable term, a cross-derivative term, which is similar to one appearing in the Gaussian filtered Vlasov equation derived by Klimas [J. Comput. Phys. 68, 202 (1987)] and also to one derived recently by Kobayashi and Shimomura [Phys. Fluids 15, L29 (2003)] from the tensor-diffusivity subgrid-scale term in a dynamic mixed model. The present result predicts that not only the numerical methods and the subgrid-scale models employed but also only the applied filtering process can be a seed of this numerical instability. An investigation concerning the relationship between the turbulent energy scattering and the unstable term shows that the instability of the term does not necessarily represent the backscatter of kinetic energy which has been considered a possible origin of numerical instabilities in large eddy simulation. The present findings raise the question whether a numerically stable subgrid-scale model can be ideally accurate.

  13. Dynamic computed tomography: a novel technique to study lung aeration and atelectasis formation during experimental CPR.

    PubMed

    Markstaller, Klaus; Karmrodt, Jens; Doebrich, Marcus; Wolcke, Benno; Gervais, Hendrik; Weiler, Norbert; Thelen, Manfred; Dick, Wolfgang; Kauczor, Hans-Ulrich; Eberle, Balthasar

    2002-06-01

    To develop an image based technique to study the effect of different ventilatory strategies on lung ventilation and alveolar recruitment during cardiopulmonary resuscitation (CPR). (1) Technical development of the following components: (a) construction of an external chest compression device, which does not interfere with CT imaging, and (b) development of a software tool to detect lung parenchyma automatically and to calculate radiological density parameters. (2) Feasibility studies: three strategies of CPR ventilation were performed and imaged in one animal each (pigs, 25 kg): volume-constant ventilation (VCV), no ventilation, or continuous airway pressure (CPAP). One minute after induction of circulatory arrest inside the CT scanner, external chest compressions started at a rate of 100 cpm, and one of the ventilation modes was initiated. After 1 min, intravenous epinephrine was added as a bolus (40 microg/kg), followed by a continuous infusion (13 microg/kg per min). Six minutes later, dynamic CT acquisitions (temporal resolution: 100 ms) commenced. Simultaneously, arterial blood gases, acid base status and haemodynamics were sampled. Using a modified chest compression device, dynamic CT acquisitions are feasible during closed-chest CPR. In three pilot experiments with different ventilation strategies, the dedicated software tool allowed to quantify ventilated, atelectatic and over-distended fractions of total lung area. VCV showed a large amount of atelectasis, which was recruited during every respiratory cycle. No ventilation led to atelectasis to govern over 50% of the total lung area. CPAP caused less atelectasis as VCV, and no cyclic recruitment and de-recruitment phenomena were observed. We demonstrate a novel experimental set up, which allows quantification of different lung compartments during ongoing CPR and may become useful in comparing the direct pulmonary effects of different ventilatory strategies in the settings of Basic and Advanced Cardiac Life Support.

  14. Prognostic Value of Epicardial Fat Volume Measurements by Computed Tomography: A Systematic Review of the Literature

    PubMed Central

    Spearman, James V.; Renker, Matthias; Schoepf, U. Joseph; Krazinski, Aleksander W.; Herbert, Teri L.; De Cecco, Carlo N.; Nietert, Paul J.; Meinel, Felix G.

    2015-01-01

    Objectives To perform a systematic review of the growing body of literature evaluating the prognostic value of epicardial fat volume (EFV) quantified by cross-sectional imaging for adverse clinical outcomes. Methods Two independent reviewers performed systematic searches on both PubMed and Scopus using search terms developed with a medical librarian. Peer-reviewed articles were selected based on the inclusion of outcome data, utilization of epicardial fat volume and sufficient reporting for analysis. Results A total of 411 studies were evaluated with 9 studies meeting the inclusion criteria. In all, the studies evaluated 10,252 patients. All 9 studies were based on CT measurements. Seven studies evaluated the prognostic value of EFV unadjusted for calcium score, and 6 of these studies found a significant association between EFV and clinical outcomes. Seven studies evaluated the incremental value of EFV beyond calcium scoring, and 6 of these studies found a significant association. Conclusions The majority of studies suggest that EFV quantification is significantly associated with clinical outcomes and provides incremental prognostic value over coronary artery calcium scoring. Future research should use a binary cut-off of 125mL for evaluation of EFV to provide consistency with other research. PMID:25925354

  15. Characterizing atherosclerotic plaque with computed tomography: a contrast-detail study

    NASA Astrophysics Data System (ADS)

    Kasraie, Nima; Clarke, Geoffrey D.

    2012-02-01

    Plaque characterization may benefit from the increasing distinctiveness of the attenuating properties of different soft plaque components at lower energies. Due to the relative slight increase in the CT number of the nonadipose soft plaque at lower tube voltage settings vs. adipose plaque, a higher contrast between atheromous adipose and non-adipose plaque may become visible with modern 64 slice systems. A contrast-detail (C-D) phantom with varying plaque composition as the contrast generating method, was imaged on a commercial 64 slice MDCT system using 80, 120, and 140 kVp settings. The same phantom was also imaged on a Cone Beam CT (CBCT) system with a lower tube voltage of 75 kVp. The results of experiments from four different observers on three different plaque types (lipid, fiber, calcific) indicate that CT attenuation within lipid cores and fibrous masses vary not only with the percentage of lipid or fiber present, but also with the size of the cores. Furthermore, the C-D curve analysis for all three plaque types reveals that while the noise constraints prevent visible differentiation of soft plaque at current conventional 64 slice MDCT settings, CBCT exhibits superior visible contrast detectability than its conventional counterpart, with the latter having appreciably better resolution limits and beneficial lower tube voltages. This low voltage CT technique has the potential to be useful in composition based diagnosis of carotid vulnerable atherosclerotic plaque.

  16. Computer simulations of 10-km-diameter asteroid impacts into oceanic and continental sites: Preliminary results on atmospheric passage, cratering and ejecta dynamics

    NASA Technical Reports Server (NTRS)

    Roddy, D. J.; Schuster, S. H.; Rosenblatt, Martin; Grant, L. B.; Hassig, P. J.; Kreyenhagen, K. N.

    1987-01-01

    A series of analytical calculations of large scale cratering events for both oceanic and continental sites were made in order to examine their effects on the target media and atmosphere. The first analytical studies that were completed consists of computer simulations of the dynamics of: (1) the passage of a 10 km diameter asteroid moving at 20 km/sec through the Earth's atmosphere, and (2) the impact cratering events in both oceanic and continental environments. Calculation of the dynamics associated with the passage of the asteroid through the atmosphere showed strong effects on the surrounding air mass. The calculations of the impact cratering events showed equally dramatic effects on the oceanic and continental environments. These effects are briefly discussed.

  17. Computed Tomography Versus Magnetic Resonance Imaging-Based Contouring in Cervical Cancer Brachytherapy: Results of a Prospective Trial and Preliminary Guidelines for Standardized Contours

    SciTech Connect

    Viswanathan, Akila N.; Dimopoulos, Johannes . E-mail: Johannes.dimopoulos@akhwien.at; Kirisits, Christian; Berger, Daniel; Poetter, Richard

    2007-06-01

    Purpose: To compare the contours and dose-volume histograms (DVH) of the tumor and organs at risk (OAR) with computed tomography (CT) vs. magnetic resonance imaging (MRI) in cervical cancer brachytherapy. Methods and Materials: Ten patients underwent both MRI and CT after applicator insertion. The dose received by at least 90% of the volume (D{sub 90}), the minimal target dose (D{sub 100}), the volume treated to the prescription dose or greater for tumor for the high-risk (HR) and intermediate-risk (IR) clinical target volume (CTV) and the dose to 0.1 cm{sup 3}, 1 cm{sup 3}, and 2 cm{sup 3} for the OARs were evaluated. A standardized approach to contouring on CT (CT{sub Std}) was developed, implemented (HR- and IR-CTV{sub CTStd}), and compared with the MRI contours. Results: Tumor height, thickness, and total volume measurements, as determined by either CT or CT{sub Std} were not significantly different compared with the MRI volumes. In contrast, the width measurements differed in HR-CTV{sub CTStd} (p = 0.05) and IR-CTV{sub CTStd} (p = 0.01). For the HR-CTV{sub CTStd}, this resulted in statistically significant differences in the volume treated to the prescription dose or greater (MRI, 96% vs. CT{sub Std}, 86%, p = 0.01), D{sub 100} (MRI, 5.4 vs. CT{sub Std}, 3.4, p <0.01), and D{sub 90} (MRI, 8.7 vs. CT{sub Std}, 6.7, p <0.01). Correspondingly, the IR-CTV DVH values on MRI vs. CT{sub Std}, differed in the D{sub 100} (MRI, 3.0 vs. CT{sub Std}, 2.2, p = 0.01) and D{sub 90} (MRI, 5.6 vs. CT{sub Std}, 4.6, p = 0.02). The MRI and CT DVH values of the dose to 0.1 cm{sup 3}, 1 cm{sup 3}, and 2 cm{sup 3} for the OARs were similar. Conclusion: Computed tomography-based or MRI-based scans at brachytherapy are adequate for OAR DVH analysis. However, CT tumor contours can significantly overestimate the tumor width, resulting in significant differences in the D{sub 90}, D{sub 100}, and volume treated to the prescription dose or greater for the HR-CTV compared with that using

  18. Comparison of Contrast-Enhanced Ultrasound and Computed Tomography in Classifying Endoleaks After Endovascular Treatment of Abdominal Aorta Aneurysms: Preliminary Experience

    SciTech Connect

    Carrafiello, Gianpaolo Lagana, Domenico; Recaldini, Chiara; Mangini, Monica; Bertolotti, Elena; Caronno, Roberto; Tozzi, Matteo; Piffaretti, Gabriele; Annibale Genovese, Eugenio; Fugazzola, Carlo

    2006-12-15

    The purpose of the study was to assess the effectiveness of contrast-enhanced ultrasonography (CEUS) in endoleak classification after endovascular treatment of an abdominal aortic aneurysm compared to computed tomography angiography (CTA). From May 2001 to April 2003, 10 patients with endoleaks already detected by CTA underwent CEUS with Sonovue (registered) to confirm the CTA classification or to reclassify the endoleak. In three conflicting cases, the patients were also studied with conventional angiography. CEUS confirmed the CTA classification in seven cases (type II endoleaks). Two CTA type III endoleaks were classified as type II using CEUS and one CTA type II endoleak was classified as type I by CEUS. Regarding the cases with discordant classification, conventional angiography confirmed the ultrasound classification. Additionally, CEUS documented the origin of type II endoleaks in all cases. After CEUS reclassification of endoleaks, a significant change in patient management occurred in three cases. CEUS allows a better attribution of the origin of the endoleak, as it shows the flow in real time. CEUS is more specific than CTA in endoleak classification and gives more accurate information in therapeutic planning.

  19. Analysis of vector models in quantification of artifacts produced by standard prosthetic inlays in Cone-Beam Computed Tomography (CBCT)--a preliminary study.

    PubMed

    Różyło-Kalinowska, Ingrid; Miechowicz, Sławomir; Sarna-Boś, Katarzyna; Borowicz, Janusz; Kalinowski, Paweł

    2014-11-17

    Cone-beam computed tomography (CBCT) is a relatively new, but highly efficient imaging method applied first in dentistry in 1998. However, the quality of the obtained slices depends among other things on artifacts generated by dental restorations as well as orthodontic and prosthetic appliances. The aim of the study was to quantify the artifacts produced by standard prosthetic inlays in CBCT images. The material consisted of 17 standard prosthetic inlays mounted in dental roots embedded in resin. The samples were examined by means of a large field of view CBCT unit, Galileos (Sirona, Germany), at 85 kV and 14 mAs. The analysis was performed using Able 3DDoctor software for data in the CT raster space as well as by means of Materialise Magics software for generated vector models (STL). The masks generated in the raster space included the area of the inlays together with image artifacts. The region of interest (ROI) of the raster space is a set of voxels from a selected range of Hounsfield units (109-3071). Ceramic inlay with zirconium dioxide (Cera Post) as well as epoxy resin inlay including silica fibers enriched with zirconium (Easy Post) produced the most intense artifacts. The smallest image distortions were created by titanium inlays, both passive (Harald Nordin) and active (Flexi Flange). Inlays containing zirconium generated the strongest artifacts, thus leading to the greatest distortions in the CBCT images. Carbon fiber inlay did not considerably affect the image quality.

  20. Assessment of myocardial perfusion and viability from routine contrast-enhanced 16-detector-row computed tomography of the heart: preliminary results.

    PubMed

    Nikolaou, Konstantin; Sanz, Javier; Poon, Michael; Wintersperger, Bernd J; Ohnesorge, Bernd; Rius, Teresa; Fayad, Zahi A; Reiser, Maximilian F; Becker, Christoph R

    2005-05-01

    To assess the diagnostic accuracy of 16-detector-row computed tomography (16DCT) of the heart in the assessment of myocardial perfusion and viability in comparison to stress perfusion magnetic resonance imaging (SP-MRI) and delayed-enhancement magnetic resonance imaging (DE-MRI). A number of 30 patients underwent both 16DCT and MRI of the heart. Contrast-enhanced 16DCT data sets were reviewed for areas of myocardium with reduced attenuation. Both CT and MRI data were examined by independent reviewers for the presence of myocardial perfusion defects or myocardial infarctions (MI). Volumetric analysis of the hypoperfusion areas in CT and the infarct sizes in DE-MRI were performed. According to MRI, myocardial infarctions were detected in 11 of 30 cases, and perfusion defects not corresponding to an MI were detected in six of 30 patients. CTA was able to detect ten of 11 MI correctly (sensitivity 91%, specificity 79%, accuracy 83%), and detected three of six hypoperfusions correctly (sensitivity 50%, specificity 92%, accuracy 79%). Assessing the volume of perfusion defects correlating to history of MI on the CT images, a systematic underestimation of the true infarct size as compared to the results of DE-MRI was found (P<0.01). Routine, contrast-enhanced 16-detector row CT of the heart can detect chronic myocardial infarctions in the majority of cases, but ischemic perfusion defects are not reliably detected under resting conditions.

  1. Optimizing Hybrid Occlusion in Face-Jaw-Teeth Transplantation: A Preliminary Assessment of Real-Time Cephalometry as Part of the Computer-Assisted Planning and Execution Workstation for Craniomaxillofacial Surgery.

    PubMed

    Murphy, Ryan J; Basafa, Ehsan; Hashemi, Sepehr; Grant, Gerald T; Liacouras, Peter; Susarla, Srinivas M; Otake, Yoshito; Santiago, Gabriel; Armand, Mehran; Gordon, Chad R

    2015-08-01

    The aesthetic and functional outcomes surrounding Le Fort-based, face-jaw-teeth transplantation have been suboptimal, often leading to posttransplant class II/III skeletal profiles, palatal defects, and "hybrid malocclusion." Therefore, a novel technology-real-time cephalometry-was developed to provide the surgical team instantaneous, intraoperative knowledge of three-dimensional dentoskeletal parameters. Mock face-jaw-teeth transplantation operations were performed on plastic and cadaveric human donor/recipient pairs (n = 2). Preoperatively, cephalometric landmarks were identified on donor/recipient skeletons using segmented computed tomographic scans. The computer-assisted planning and execution workstation tracked the position of the donor face-jaw-teeth segment in real time during the placement/inset onto recipient, reporting pertinent hybrid cephalometric parameters from any movement of donor tissue. The intraoperative data measured through real-time cephalometry were compared to posttransplant measurements for accuracy assessment. In addition, posttransplant cephalometric relationships were compared to planned outcomes to determine face-jaw-teeth transplantation success. Compared with postoperative data, the real-time cephalometry-calculated intraoperative measurement errors were 1.37 ± 1.11 mm and 0.45 ± 0.28 degrees for the plastic skull and 2.99 ± 2.24 mm and 2.63 ± 1.33 degrees for the human cadaver experiments. These results were comparable to the posttransplant relations to planned outcome (human cadaver experiment, 1.39 ± 1.81 mm and 2.18 ± 1.88 degrees; plastic skull experiment, 1.06 ± 0.63 mm and 0.53 ± 0.39 degrees). Based on this preliminary testing, real-time cephalometry may be a valuable adjunct for adjusting and measuring "hybrid occlusion" in face-jaw-teeth transplantation and other orthognathic surgical procedures.

  2. Optimizing Hybrid Occlusion in Face-Jaw-Teeth Transplantation: A Preliminary Assessment of Real-Time Cephalometry as Part of the Computer-Assisted Planning and Execution Workstation for Craniomaxillofacial Surgery

    PubMed Central

    Murphy, Ryan J.; Basafa, Ehsan; Hashemi, Sepehr; Grant, Gerald T.; Liacouras, Peter; Susarla, Srinivas M.; Otake, Yoshito; Santiago, Gabriel; Armand, Mehran; Gordon, Chad R.

    2016-01-01

    Background The aesthetic and functional outcomes surrounding Le Fort–based, face-jaw-teeth transplantation have been suboptimal, often leading to posttransplant class II/III skeletal profiles, palatal defects, and “hybrid malocclusion.” Therefore, a novel technology—real-time cephalometry—was developed to provide the surgical team instantaneous, intraoperative knowledge of three-dimensional dentoskeletal parameters. Methods Mock face-jaw-teeth transplantation operations were performed on plastic and cadaveric human donor/recipient pairs (n = 2). Preoperatively, cephalometric landmarks were identified on donor/recipient skeletons using segmented computed tomographic scans. The computer-assisted planning and execution workstation tracked the position of the donor face-jaw-teeth segment in real time during the placement/inset onto recipient, reporting pertinent hybrid cephalometric parameters from any movement of donor tissue. The intraoperative data measured through real-time cephalometry were compared to posttransplant measurements for accuracy assessment. In addition, posttransplant cephalometric relationships were compared to planned outcomes to determine face-jaw-teeth transplantation success. Results Compared with postoperative data, the real-time cephalometry–calculated intraoperative measurement errors were 1.37 ± 1.11 mm and 0.45 ± 0.28 degrees for the plastic skull and 2.99 ± 2.24 mm and 2.63 ± 1.33 degrees for the human cadaver experiments. These results were comparable to the posttransplant relations to planned outcome (human cadaver experiment, 1.39 ± 1.81 mm and 2.18 ± 1.88 degrees; plastic skull experiment, 1.06 ± 0.63 mm and 0.53 ± 0.39 degrees). Conclusion Based on this preliminary testing, real-time cephalometry may be a valuable adjunct for adjusting and measuring “hybrid occlusion” in face-jaw-teeth transplantation and other orthognathic surgical procedures. PMID:26218382

  3. Low-Dose Scanning Technology Combined with Low-Concentration Contrast Material in Renal Computed Tomography Angiography (CTA): A Preliminary Study.

    PubMed

    Liu, Sulan; Li, Wei; Shi, Hao; Sheng, Huaqiang; Fan, Jingli; He, Jingzhen; Sun, Hongjun

    2017-09-09

    BACKGROUND This study is to investigate the feasibility of low iodine concentration contrast material (CM) combined with low tube voltage and adaptive statistical iterative reconstruction (ASIR) in renal computed tomography angiography (CTA). MATERIAL AND METHODS A total of 136 patients were enrolled in this prospective trial, and randomly divided into two groups: group A (n=68) and group B (n=68). Group A received 120-kVp and iopromide (370 mg/mL) with filtered back projection (FBP) reconstruction, and group B received 100-kVp and iodixanol (270 mg/mL) with ASIR 40% (ASIR40). An equal iodine dose (300 mg/kg body weight) and the same iodine delivery rate (1,500 mg I/s) were given to all patients. Density, image noise, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) were measured, and the image quality and visualization of renal arteries were scored. Dose-length product (DLP) and CT dose index volume (CTDIvol) were recorded, and effective doses (ED) were calculated. RESULTS There was no significant difference in image noise between groups A and B (p>0.05). The vessel attenuation, SNR, and CNR were significantly higher in group B than group A (all p<0.05). The subjective image quality and visualization of renal artery branches were similar in these two groups (p>0.05). Compared with group A, the CTDIvol, DLP, and ED in group B were decreased by 38.58%, 37.24%, and 37.24%, respectively (p=0.000). CONCLUSIONS Compared with 120-kVp with FBP reconstruction, the protocol of 100-kVp with ASIRP40 reconstruction provided high-quality renal CTA results, which allowed for reduced iodine concentration and decreased radiation dose.

  4. The diagnostic value of computed tomographic coronary angiography in patients with acute myocardial infarction versus stable angina pectoris: a preliminary report.

    PubMed

    Chen, Shih-Jen; Kuo, Li-Tang; Wang, Chao-Hung; Cherng, Wen-Jin; Yang, Ning-I; Cheng, Chi-Wen

    2011-01-01

    Computed tomographic coronary angiography (CTA) is a non-invasive alternative to conventional coronary angiography (CCA) in detecting chronic coronary artery disease (CAD). However, the value of CTA in estimating acute myocardial infarction (AMI) has not been evaluated. CTA and CCA were performed on 10 patients with non-ST-elevated AMI and 17 patients with stable angina pectoris. The plaque components and stenosis severity were assessed by both modalities to clarify the diagnostic values of CTA in AMI and stable angina pectoris. A high total coronary artery calcium (CAC) score was significantly correlated with the presence of CAD and the target lesion CAC score (p < 0.01). The AMI group tended to have a lower target CAC score (p = 0.10) and target plaque burden (p = 0.27), compared to the stable angina pectoris group. To estimate the coronary artery stenotic severity, CTA and CCA had concordant correlations in all segments, except in the proximal left anterior descending (LAD) artery. The calcium score and calcification fraction percentage in the proximal LAD artery were significantly higher than those of other segments (p < 0.01). Compared to CCA, CTA overestimated the severity of stenosis in the proximal LAD arterial segment in the stable angina pectoris group (p = 0.028), but not in the AMI group. CTA has diagnostic values similar to those of CCA in detecting coronary lesions in patients with AMI or stable angina pectoris. However, a high level of plaque CAC in the stable angina pectoris group may lead to an overestimation of the severity of coronary stenosis, especially in the proximal LAD arterial segment. Although less remarkable, the impact of CAC on the diagnostic value of CTA was still substantial in patients with AMI.

  5. A database of body-only computer-generated pictures of women for body-image studies: Development and preliminary validation.

    PubMed

    Moussally, Joanna M; Rochat, Lucien; Posada, Andrés; Van der Linden, Martial

    2017-02-01

    The body-shape-related stimuli used in most body-image studies have several limitations (e.g., a lack of pilot validation procedures and the use of non-body-shape-related control/neutral stimuli). We therefore developed a database of 61 computer-generated body-only pictures of women, wherein bodies were methodically manipulated in terms of fatness versus thinness. Eighty-two young women assessed the pictures' attractiveness, beauty, harmony (valence ratings), and body shape (assessed on a thinness/fatness axis), providing normative data for valence and body shape ratings. First, stimuli manipulated for fatness versus thinness conveyed comparable emotional intensities regarding the valence and body shape ratings. Second, different subcategories of stimuli were obtained on the basis of variations in body shape and valence judgments. Fat and thin bodies were distributed into several subcategories depending on their valence ratings, and a subcategory containing stimuli that were neutral in terms of valence and body shape was identified. Interestingly, at a descriptive level, the thinness/fatness manipulations of the bodies were in a curvilinear relationship with the valence ratings: Thin bodies were not only judged as positive, but also as negative when their estimated body mass indexes (BMIs) decreased too much. Finally, convergent validity was assessed by exploring the impacts of body-image-related variables (BMI, thin-ideal internalization, and body dissatisfaction) on participants' judgments of the bodies. Valence judgments, but not body shape judgments, were influenced by the participants' levels of thin-ideal internalization and body dissatisfaction. Participants' BMIs did not significantly influence their judgments. Given these findings, this database contains relevant material that can be used in various fields, primarily for studies of body-image disturbance or eating disorders.

  6. Quantification of left coronary bifurcation angles and plaques by coronary computed tomography angiography for prediction of significant coronary stenosis: A preliminary study with dual-source CT

    PubMed Central

    Cui, Yue; Zeng, Wenjuan; Yu, Jie; Lu, Jing; Hu, Yuannan; Diao, Nan; Liang, Bo; Han, Ping; Shi, Heshui

    2017-01-01

    Purpose To evaluate the diagnostic performance of left coronary bifurcation angles and plaque characteristics for prediction of coronary stenosis by dual-source CT. Methods 106 patients suspected of coronary artery disease undergoing both coronary computed tomography angiography (CCTA) and invasive coronary angiography (CAG) within three months were included. Left coronary bifurcation angles including the angles between the left anterior descending artery and left circumflex artery (LAD-LCx), left main coronary artery and left anterior descending artery (LM-LAD), left main coronary artery and left circumflex artery (LM-LCx) were measured on CT images. CCTA plaque parameters were calculated by plaque analysis software. Coronary stenosis ≥ 50% by CAG was defined as significant. Results 106 patients with 318 left coronary bifurcation angles and 126 vessels were analyzed. The bifurcation angle of LAD-LCx was significantly larger in left coronary stenosis ≥ 50% than stenosis < 50%, and significantly wider in the non-calcified plaque group than calcified. Multivariable analyses showed the bifurcation angle of LAD-LCx was an independent predictor for significant left coronary stenosis (OR = 1.423, P = 0.002). In ROC curve analysis, LAD-LCx predicted significant left coronary stenosis with a sensitivity of 66.7%, specificity of 78.4%, positive predictive value of 85.2% and negative predictive value of 55.8%. The lipid plaque volume improved the diagnostic performance of CCTA diameter stenosis (AUC: 0.854 vs. 0.900, P = 0.045) in significant coronary stenosis. Conclusions The bifurcation angle of LAD-LCx could predict significant left coronary stenosis. Wider LAD-LCx is related to non-calcified lesions. Lipid plaque volume could improve the diagnostic performance of CCTA for coronary stenosis prediction. PMID:28346530

  7. Mosaic tile model to compute gravitational field for infinitely thin non-axisymmetric objects and its application to preliminary analysis of gravitational field of M74

    NASA Astrophysics Data System (ADS)

    Fukushima, Toshio

    2016-07-01

    Using the analytical expressions of the Newtonian gravitational potential and the associated acceleration vector for an infinitely thin uniform rectangular plate, we developed a method to compute the gravitational field of a general infinitely thin object without assuming its axial symmetry when its surface mass density is known at evenly spaced rectangular grid points. We utilized the method in evaluating the gravitational field of the H I gas, dust, red stars, and blue stars components of M74 from its THINGS, 2MASS, PDSS1, and GALEX data. The non-axisymmetric feature of M74 including an asymmetric spiral structure is seen from (i) the contour maps of the determined gravitational potential, (ii) the vector maps of the associated acceleration vector, and (iii) the cross-section views of the gravitational field and the surface mass density along different directions. An x-mark pattern in the gravitational field is detected at the core of M74 from the analysis of its dust and red stars components. Meanwhile, along the east-west direction in the central region of the angular size of 1 arcmin, the rotation curve derived from the radial component of the acceleration vector caused by the red stars component matches well with that observed by the VENGA project. Thus the method will be useful in studying the dynamics of particles and fluids near and inside spiral galaxies with known photometry data. Electronically available are the table of the determined gravitational fields of M74 on its galactic plane as well as the FORTRAN 90 programs to produce them.

  8. Preliminary experience on the implementation of computed tomography (CT)-based image guided brachytherapy (IGBT) of cervical cancer using high-dose-rate (HDR) Cobalt-60 source in University of Malaya Medical Centre (UMMC)

    NASA Astrophysics Data System (ADS)

    Jamalludin, Z.; Min, U. N.; Ishak, W. Z. Wan; Malik, R. Abdul

    2016-03-01

    This study presents our preliminary work of the computed tomography (CT) image guided brachytherapy (IGBT) implementation on cervical cancer patients. We developed a protocol in which patients undergo two Magnetic Resonance Imaging (MRI) examinations; a) prior to external beam radiotherapy (EBRT) and b) prior to intra-cavitary brachytherapy for tumour identification and delineation during IGBT planning and dosimetry. For each fraction, patients were simulated using CT simulator and images were transferred to the treatment planning system. The HR-CTV, IR-CTV, bladder and rectum were delineated on CT-based contouring for cervical cancer. Plans were optimised to achieve HR-CTV and IR-CTV dose (D90) of total EQD2 80Gy and 60Gy respectively, while limiting the minimum dose to the most irradiated 2cm3 volume (D2cc) of bladder and rectum to total EQD2 90Gy and 75Gy respectively. Data from seven insertions were analysed by comparing the volume-based with traditional point- based doses. Based on our data, there were differences between volume and point doses of HR- CTV, bladder and rectum organs. As the number of patients having the CT-based IGBT increases from day to day in our centre, it is expected that the treatment and dosimetry accuracy will be improved with the implementation.

  9. Preliminary Report: Results of Computed Tracer Concentrations over Eastern China, South Korea, and Japan for 01 March to 30 May 2007 Daily Simulated Releases from Taiyuan, China

    SciTech Connect

    Vogt, P

    2007-08-07

    In order to prepare for a proposed long range tracer experiment in China for the spring of 2008 time period, NARAC computed hypothetical PMCH concentrations over Eastern China, South Korea and Japan for simulated releases from Taiyuan, China. Normalized 1 kg of PMCH source strength releases were made twice a day, with wind input from global forecast weather model. We used 6-hour analysis fields valid at the start of each model run, resulting in four wind fields per day. The selected domain encompassed the region of interest over eastern Asia and the Western Pacific. Screening runs were made for each day at 0000 and 1200 UTC from 01 April, 2007 through 29 May, 2007 for a total of 90 days and 180 cases. 24-hour average air concentrations were evaluated at 22 sample cities in the three regions of interest for each case. 15 sample cities were selected to help quantify modeling results for experiment objectives. Any case that resulted in model predicted air concentrations exceeding 2.0E-02 fL/L at a sample city in all three regions was then selected for a detailed model run with source times six hours before and after evaluated in addition to the case time. The detailed runs used the same wind fields and model domain, but 6-hour average air concentrations were generated and analyzed for the 15 sample cities. Each of the 180 cases were ranked subjectively, based on whether or not the model prediction indicated the possibility that a release on that date and time might achieve the long range experiment objectives. Ranks used are High, Good, Low, Poor, and Bad. Of the 180 cases run, NARAC dispersion models predicted 6 instances of High possibility, 8 cases of Good, 32 of Low, 74 of Poor, and 60 cases of Bad probability. Detailed model runs were made for all 14 High or Good probability cases, a total of only 7.8% of all analyzed. Based on the results of this study we have identified a few dates on which a release of a reasonable amount of PMCH tracer (on the order of 500 kg

  10. Preliminary clinical study in patients with hemispatial neglect after stroke by neglect test battery and 99mTc-ECD single-photon emission computed tomography.

    PubMed

    Yin, Yafu; Li, Xuena; Li, Yaming; Gu, Hui; Han, Chunqi; Liu, Hao

    2009-05-01

    To explore the presence, clinical characteristics, anatomical foci in image and mechanism of hemispatial neglect (HSN), neglect test battery and single-photon emission computed tomography (SPECT) regional cerebral blood flow (rCBF) imaging were performed on patients with stroke. Thirty dextromanual patients who were diagnosed as having unilateral stroke clinically were recruited. A neglect test battery including line bisection test, star cancellation test and drawing test was performed on the subjects. The severity of neglect was measured on neglect tests. The lowest rCBF, the range with decreased rCBF, number of the foci with decreased rCBF, the flow deficit size and the total number of pixels in the foci were measured on SPECT rCBF imaging. Twenty-five patients were diagnosed as having HSN by the neglect test battery. Contralateral neglect (CN) and ipsilateral neglect (IN) were observed in both right and left hemisphere strokes. On SPECT imaging, the patients with neglect had decreased rCBF in the frontal cortex most often; followed by the parietal, occipital and temporal cortices; and basal ganglia and thalamus in some cases. The patients who had two or more regions damaged showed neglect more often and severity. The correlation coefficients between rCBF in the foci, the decreased percentage of rCBF of the foci and the severity of neglect were -0.119 (P>.05) and 0.221 (P>.05). The correlation coefficients between the range, number of foci, the flow deficit size, the total number of pixels of the foci and the severity of neglect were 0.537 (P<.05), 0.493 (P<.05), 0.561 (P<.05), 0.466 (P<.05), respectively. No difference between CN and IN on SPECT images reached statistical significance. The severity of neglect did not correlate with rCBF and the decreased percentage of rCBF in the foci, while it was significantly correlated with the range, number of foci, the flow deficit size and the total numbers of pixels of the foci significantly. And the patients with CN and

  11. Evaluation of pulmonary function using single-breath-hold dual-energy computed tomography with xenon: Results of a preliminary study.

    PubMed

    Kyoyama, Hiroyuki; Hirata, Yusuke; Kikuchi, Satoshi; Sakai, Kosuke; Saito, Yuriko; Mikami, Shintaro; Moriyama, Gaku; Yanagita, Hisami; Watanabe, Wataru; Otani, Katharina; Honda, Norinari; Uematsu, Kazutsugu

    2017-01-01

    Xenon-enhanced dual-energy computed tomography (xenon-enhanced CT) can provide lung ventilation maps that may be useful for assessing structural and functional abnormalities of the lung. Xenon-enhanced CT has been performed using a multiple-breath-hold technique during xenon washout. We recently developed xenon-enhanced CT using a single-breath-hold technique to assess ventilation. We sought to evaluate whether xenon-enhanced CT using a single-breath-hold technique correlates with pulmonary function testing (PFT) results.Twenty-six patients, including 11 chronic obstructive pulmonary disease (COPD) patients, underwent xenon-enhanced CT and PFT. Three of the COPD patients underwent xenon-enhanced CT before and after bronchodilator treatment. Images from xenon-CT were obtained by dual-source CT during a breath-hold after a single vital-capacity inspiration of a xenon-oxygen gas mixture. Image postprocessing by 3-material decomposition generated conventional CT and xenon-enhanced images.Low-attenuation areas on xenon images matched low-attenuation areas on conventional CT in 21 cases but matched normal-attenuation areas in 5 cases. Volumes of Hounsfield unit (HU) histograms of xenon images correlated moderately and highly with vital capacity (VC) and total lung capacity (TLC), respectively (r = 0.68 and 0.85). Means and modes of histograms weakly correlated with VC (r = 0.39 and 0.38), moderately with forced expiratory volume in 1 second (FEV1) (r = 0.59 and 0.56), weakly with the ratio of FEV1 to FVC (r = 0.46 and 0.42), and moderately with the ratio of FEV1 to its predicted value (r = 0.64 and 0.60). Mode and volume of histograms increased in 2 COPD patients after the improvement of FEV1 with bronchodilators. Inhalation of xenon gas caused no adverse effects.Xenon-enhanced CT using a single-breath-hold technique depicted functional abnormalities not detectable on thin-slice CT. Mode, mean, and volume of HU histograms of xenon images reflected

  12. A PRELIMINARY JUPITER MODEL

    SciTech Connect

    Hubbard, W. B.; Militzer, B.

    2016-03-20

    In anticipation of new observational results for Jupiter's axial moment of inertia and gravitational zonal harmonic coefficients from the forthcoming Juno orbiter, we present a number of preliminary Jupiter interior models. We combine results from ab initio computer simulations of hydrogen–helium mixtures, including immiscibility calculations, with a new nonperturbative calculation of Jupiter's zonal harmonic coefficients, to derive a self-consistent model for the planet's external gravity and moment of inertia. We assume helium rain modified the interior temperature and composition profiles. Our calculation predicts zonal harmonic values to which measurements can be compared. Although some models fit the observed (pre-Juno) second- and fourth-order zonal harmonics to within their error bars, our preferred reference model predicts a fourth-order zonal harmonic whose absolute value lies above the pre-Juno error bars. This model has a dense core of about 12 Earth masses and a hydrogen–helium-rich envelope with approximately three times solar metallicity.

  13. Multidisciplinary Optimization Methods for Preliminary Design

    NASA Technical Reports Server (NTRS)

    Korte, J. J.; Weston, R. P.; Zang, T. A.

    1997-01-01

    An overview of multidisciplinary optimization (MDO) methodology and two applications of this methodology to the preliminary design phase are presented. These applications are being undertaken to improve, develop, validate and demonstrate MDO methods. Each is presented to illustrate different aspects of this methodology. The first application is an MDO preliminary design problem for defining the geometry and structure of an aerospike nozzle of a linear aerospike rocket engine. The second application demonstrates the use of the Framework for Interdisciplinary Design Optimization (FIDO), which is a computational environment system, by solving a preliminary design problem for a High-Speed Civil Transport (HSCT). The two sample problems illustrate the advantages to performing preliminary design with an MDO process.

  14. Computational prediction of propellant reorientation

    NASA Technical Reports Server (NTRS)

    Hochstein, John I.

    1987-01-01

    Viewgraphs from a presentation on computational prediction of propellant reorientation are given. Information is given on code verification, test conditions, predictions for a one-quarter scale cryogenic tank, pulsed settling, and preliminary results.

  15. 2016 TRI Preliminary Dataset

    EPA Pesticide Factsheets

    The TRI preliminary dataset includes the most current TRI data available and reflects toxic chemical releases and pollution prevention activities that occurred at TRI facilities during the 2016 calendar year.

  16. Preliminary Drill Sites

    DOE Data Explorer

    Lane, Michael

    2013-06-28

    Preliminary locations for intermediate depth temperature gradient holes and/or resource confirmation wells based on compilation of geological, geophysical and geochemical data prior to carrying out the DOE-funded reflection seismic survey.

  17. Visualisation of passive middle ear implants by cone beam and multi-detector computed tomography: a comparative in vitro study.

    PubMed

    Nguyen, T D; Kösling, S; Mlynski, R; Plontke, S K

    2016-12-01

    Modern passive middle ear titanium prostheses are filigree structures, resulting in poorer depiction on CT compared to prostheses used in the past. We compared the visibility of newer prostheses on cone beam CT (CBCT) to multi-detector CT (MDCT) with standard and lower dose in vitro, and analysed image noise and metal artefacts. Six different titanium middle ear prostheses (three partial and one total ossicular replacement prostheses, two stapes prostheses) were implanted twice in formalin-fixed head specimens-first correctly and then with displacement. Imaging was performed using standard CBCT and MDCT as well as MDCT with lower dose (36 single imaging investigations). Images were analysed with knowledge of the used types of middle ear prostheses, but blinded with respect to the positioning in the specific case. On all images the type of prostheses and their positions could be clearly recognized. Their identifiability including their details was rated as statistically significantly higher for all CBCT investigations than for MDCT. MDCT with lower dose showed the worst results. No statistical differences were found in image noise and metal artefacts. If available, CBCT should be preferred over MDCT in diagnostic evaluation of passive middle ear prostheses. • Middle ear prostheses became more filigree, leading to poorer visibility on CT. • High spatial resolution and paraxial reconstructions are necessary requirements for imaging evaluation. • CBCT and MDCT can identify type and positioning of titanium prostheses. • Metal artefacts play a minor part in filigree titanium prostheses. • Regarding visualisation of prostheses details, cone beam CT aids the evaluation.

  18. Effective dose to patient measurements in flat-detector and multislice computed tomography: a comparison of applications in neuroradiology.

    PubMed

    Struffert, Tobias; Hauer, Michael; Banckwitz, Rosemarie; Köhler, Christoph; Royalty, Kevin; Doerfler, Arnd

    2014-06-01

    Flat-detector CT (FD-CT) is used for a variety of applications. Additionally, 3D rotational angiography (3D DSA) is used to supplement digital subtraction angiography (DSA) studies. The aim was to measure and compare the dose of (1) standard DSA and 3D DSA and (2) analogous FD-CT and multislice CT (MSCT) protocols. Using an anthropomorphic phantom, the effective dose to patients (according to ICRP 103) was measured on an MSCT and a flat-detector angiographic system using standard protocols as recommended by the manufacturer. (1) Evaluation of DSA and 3D DSA angiography protocols: ap.-lat. Standard/low-dose series 1/0.8 mSv, enlarged oblique projection 0.3 mSv, 3D DSA 0.9 mSv (limited coverage length 0.3 mSv). (2) Comparison of FD-CT and MSCT: brain parenchyma imaging 2.9 /1.4 mSv, perfusion imaging 2.3/4.2 mSv, temporal bone 0.2 /0.2 mSv, angiography 2.9/3.3 mSv, limited to the head using collimation 0.5/0.5 mSv. The effective dose for an FD-CT application depends on the application used. Using collimation for FD-CT applications, the dose may be reduced considerably. Due to the low dose of 3D DSA, we recommend using this technique to reduce the number of DSA series needed to identify working projections. Effective dose of FD-CT in comparison to MSCT is in comparable range. Collimation decreases the dose of FD-CT effectively. Effective dose of 3-D angiography is identical to 2-D DSA. Different FD-CT programs have different dose.

  19. Ultrafast Cone-Beam Computed Tomography: A Comparative Study of Imaging Protocols during Image-Guided Therapy Procedure

    PubMed Central

    Chacko, Annamma; Farhang, Mohammad; Kamali, Shahram; Tavanania, Mohsen; Vogl, Thomas; Panahi, Bita

    2015-01-01

    Objective. To evaluate two ultrafast cone-beam CT (UF-CBCT) imaging protocols with different acquisition and injection parameters regarding image quality and required contrast media during image-guided hepatic transarterial chemoembolization (TACE). Methods. In 80 patients (male: 46, female: 34; mean age: 56.8 years; range: 33–83) UF-CBCT was performed during TACE for intraprocedural guidance. Imaging was performed using two ultrafast CBCT acquisition protocols with different acquisition and injection parameters (imaging protocol 1: acquisition time 2.54 s, and contrast 6 mL with 3 s delay; imaging protocol 2: acquisition time 2.72 s, and contrast 7 mL with 6 s delay). Image evaluation was performed with both qualitative and quantitative methods. Contrast injection volume and dose parameters were compared using values from the literature. Results. Imaging protocol 2 provided significantly better (P < 0.05) image quality than protocol 1 at the cost of slightly higher contrast load and patient dose. Imaging protocol 1 provided good contrast perfusion but it mostly failed to delineate the tumors (P < 0.05). On the contrary, imaging protocol 2 showed excellent enhancement of hepatic parenchyma, tumor, and feeding vessels. Conclusion. Tumor delineation, visualization of hepatic parenchyma, and feeding vessels are clearly possible using imaging protocol 2 with ultrafast CBCT imaging. A reduction of required contrast volume and patient dose were achieved due to the ultrafast CBCT imaging. PMID:25874213

  20. Computer-Graphical Simulation Of Robotic Welding

    NASA Technical Reports Server (NTRS)

    Fernandez, Ken; Cook, George

    1988-01-01

    Computer program ROBOSIM, developed to simulate operations of robots, applied to preliminary design of robotic arc-welding operation. Limitations on equipment investigated in advance to prevent expensive mistakes. Computer makes drawing of robotic welder and workpiece on positioning table. Such numerical simulation used to perform rapid, safe experiments in computer-aided design or manufacturing.

  1. Notification: Audit of EPA's Cloud Computer Initiative

    EPA Pesticide Factsheets

    Project #OA-FY13-0095, December 17, 2012. The U.S. Environmental Protection Agency (EPA) Office of Inspector General plans to begin preliminary research on the audit of EPA’s cloud computer initiative.

  2. Aerodynamic preliminary analysis

    NASA Technical Reports Server (NTRS)

    Bonner, E.; Clever, W.; Divan, P.; Dunn, K.; Kojima, J.

    1981-01-01

    Computerization of aerodynamic theory has progressed to state where analysis of complete aircraft configurations can be performed in single program. Aerodynamic Preliminary Analysis System, APAS, is comprehensive aerodynamic analysis system, based on linearized potential theory. Three-dimensional configurations (with or without jet flaps) having multiple nonplanar surfaces of arbitrary planform and open or closed slender bodies of noncircular contour may be analyzed with APAS. As preliminary design aid, APAS allows designer to survey systematically large number of alternative configurations and component geometries economically.

  3. Preliminary Response Analysis of AUV

    NASA Astrophysics Data System (ADS)

    Hariri, Azian; Basharie, Siti Mariam; Ghani, Mohamad Hanifah Abd.

    2010-06-01

    Development of Autonomous Unmanned Vehicle (AUV) involves a great task to fully understand the overall working principles of an UAV that needed time, experience and a wide range of intelligence to cover the entire scientific facts. This study is done by means to acquire the fundamental knowledge in understanding the stability and response of an UAV. The longitudinal response and stability of UAV owing to deflection of stern plane during trimmed equilibrium motion can be computed by solving the AUV equation of motion. In this study, the AUV equations of motion were rederived and the solution was computed with the aid of Matlab software. From the existing AUV, a new dimension, weight and speed were specified to be used in the rederivation of the linearised AUV longitudinal equations of motion. From the analysis done, the longitudinal response AUV shows the stern plane and thrust has relatively steady longitudinal control power and quick response characteristic. The results had successfully given a preliminary insight of the specified AUV response and dynamic stability.

  4. Preliminary Cruise Report - Iguana Expedition

    DTIC Science & Technology

    A preliminary cruise report of Expedition Iguana , 31 March 1972-11 May 1972, gives some preliminary results, list of equipment and, personnel, stations and data gathered, and track and topographic plots. (Author)

  5. Preliminary AirMSPI Datasets

    Atmospheric Science Data Center

    2016-12-06

    ... Preliminary AirMSPI Datasets   The data files available through this web page and ftp links are preliminary ... geometric corrections. Caution should be used for science analysis. At a later date, more qualified versions will be made public.   ...

  6. Is Micro-Computer Assisted Basics Skills Instruction Good for Black, Disadvantaged Community College Students from Watts and Similar Communities? A Preliminary, Fall Semester 1981-82 Mini Audit Report Suggests Caution.

    ERIC Educational Resources Information Center

    Kester, Donald L.

    This report assesses the economic viability of micro-computer assisted basic skills instruction at Los Angeles Southwest College, an institution in which 96% of the students are from minority groups, the majority are from low-income families, and most have low levels of academic achievement (averaging a seventh-grade level in reading skills).…

  7. Preliminary Advanced Colloids Experiment

    NASA Image and Video Library

    2011-09-29

    ISS029-E-011867 (29 Sept. 2011) --- NASA astronaut Mike Fossum, Expedition 29 commander, works with the Light Microscopy Module (LMM) control box in the Destiny laboratory of the International Space Station in preparation for another session with the Preliminary Advanced Colloids Experiment (PACE) hardware.

  8. Cognitive remediation for adolescents with 22q11 deletion syndrome (22q11DS): A preliminary study examining effectiveness, feasibility, and fidelity of a hybrid strategy, remote and computer-based intervention

    PubMed Central

    Mariano, Margaret A.; Tang, Kerri; Kurtz, Matthew; Kates, Wendy R.

    2015-01-01

    Background 22q11DS is a multiple anomaly syndrome involving intellectual and behavioral deficits, and increased risk for schizophrenia. As cognitive remediation (CR) has recently been found to improve cognition in younger patients with schizophrenia, we investigated the efficacy, feasibility, and fidelity of a remote, hybrid strategy, computerized CR program in youth with 22q11DS. Methods A longitudinal design was implemented in which 21 participants served as their own controls. Following an eight month baseline period in which no interventions were provided, cognitive coaches met with participants remotely for CR via video conferencing three times a week over a targeted 8 month timeframe and facilitated their progress through the intervention, offering task-specific strategies. A subset of strategies were examined for fidelity. Outcomes were evaluated using a neurocognitive test battery at baseline, pre-treatment and post-treatment. Results All participants adhered to the intervention. The mean length of the treatment phase was 7.96 months. A moderately high correlation (intraclass correlation coefficient, 0.73) was found for amount and type of strategies offered by coaches. Participants exhibited significant improvements (ES = .36–.55, p ≤ .009) in working memory, shifting attention and cognitive flexibility. All significant models were driven by improvements in pre to post-treatment scores. Conclusions Based on our preliminary investigation, a remote, hybrid strategy, computerized CR program can be implemented with 22q11DS youth despite geographic location, health, and cognitive deficits. It appears effective in enhancing cognitive skills during the developmental period of adolescence, making this type of CR delivery useful for youth with 22q11DS transitioning into post-school environments. PMID:26044111

  9. Computers and Computer Resources.

    ERIC Educational Resources Information Center

    Bitter, Gary

    1980-01-01

    This resource directory provides brief evaluative descriptions of six popular home computers and lists selected sources of educational software, computer books, and magazines. For a related article on microcomputers in the schools, see p53-58 of this journal issue. (SJL)

  10. Genesis Preliminary Examination Plans

    NASA Technical Reports Server (NTRS)

    McNamara, K. M.; Stansbery, E. K.

    2004-01-01

    The purpose of preliminary examination of the Genesis sample collectors is to provide information on the condition and availability of collector materials to the science community as a basis for allocation requests. Similarly, the information will be used by the Genesis Sample Allocation sub-committee of CAPTEM to determine the optimum allocation scheme, and by the Genesis Curator to determine the processing sequence for allocation production. The plan includes a decision process and detailed examination and documentation protocol for whole arrays and individual collectors (wafers, concentrator targets, bulk metallic glass, gold foil, and polished aluminum). It also includes a plan for communicating the information obtained to the scientific community. The plan does not include a detailed plan for preliminary examination of the SRC lid foil collectors, the process for removal of individual collectors from their frames, or for the subsequent subdivision of collector materials for allocation.

  11. On Preliminary Breakdown

    NASA Astrophysics Data System (ADS)

    Beasley, W. H.; Petersen, D.

    2013-12-01

    The preliminary breakdown phase of a negative cloud-to-ground lightning flash was observed in detail. Observations were made with a Photron SA1.1 high-speed video camera operating at 9,000 frames per second, fast optical sensors, a flat-plate electric field antenna covering the SLF to MF band, and VHF and UHF radio receivers with bandwidths of 20 MHz. Bright stepwise extensions of a negative leader were observed at an altitude of 8 km during the first few milliseconds of the flash, and were coincident with bipolar electric field pulses called 'characteristic pulses'. The 2-D step lengths of the preliminary processes were in excess of 100 meters, with some 2-D step lengths in excess of 200 meters. Smaller and shorter unipolar electric field pulses were superposed onto the bipolar electric field pulses, and were coincident with VHF and UHF radio pulses. After a few milliseconds, the emerging negative stepped leader system showed a marked decrease in luminosity, step length, and propagation velocity. Details of these events will be discussed, including the possibility that the preliminary breakdown phase consists not of a single developing lightning leader system, but of multiple smaller lightning leader systems that eventually join together into a single system.

  12. ASCI 2010 appropriateness criteria for cardiac computed tomography: a report of the Asian Society of Cardiovascular Imaging Cardiac Computed Tomography and Cardiac Magnetic Resonance Imaging Guideline Working Group.

    PubMed

    Tsai, I-Chen; Choi, Byoung Wook; Chan, Carmen; Jinzaki, Masahiro; Kitagawa, Kakuya; Yong, Hwan Seok; Yu, Wei

    2010-02-01

    In Asia, the healthcare system, populations and patterns of disease differ from Western countries. The current reports on the criteria for cardiac CT scans, provided by Western professional societies, are not appropriate for Asian cultures. The Asian Society of Cardiovascular Imaging, the only society dedicated to cardiovascular imaging in Asia, formed a Working Group and invited 23 Technical Panel members representing a variety of Asian countries to rate the 51 indications for cardiac CT in clinical practice in Asia. The indications were rated as 'appropriate' (7-9), 'uncertain' (4-6), or 'inappropriate' (1-3) on a scale of 1-9. The median score was used for the final result if there was no disagreement. The final ratings for indications were 33 appropriate, 14 uncertain and 4 inappropriate. And 20 of them are highly agreed (19 appropriate and 1 inappropriate). Specifically, the Asian representatives considered cardiac CT as an appropriate modality for Kawasaki disease and congenital heart diseases in follow up and in symptomatic patients. In addition, except for some specified conditions, cardiac CT was considered to be an appropriate modality for one-stop shop ischemic heart disease evaluation due to its general appropriateness in coronary, structure and function evaluation. This report is expected to have a significant impact on the clinical practice, research and reimbursement policy in Asia.

  13. A preliminary weather model for optical communications through the atmosphere

    NASA Technical Reports Server (NTRS)

    Shaik, K. S.

    1988-01-01

    A preliminary weather model is presented for optical propagation through the atmosphere. It can be used to compute the attenuation loss due to the atmosphere for desired link availability statistics. The quantitative results that can be obtained from this model provide good estimates for the atmospheric link budget necessary for the design of an optical communication system. The result is extended to provide for the computation of joint attenuation probability for n sites with uncorrelated weather patterns.

  14. Preliminary System Design of the SWRL Financial System.

    ERIC Educational Resources Information Center

    Ikeda, Masumi

    The preliminary system design of the computer-based Southwest Regional Laboratory's (SWRL) Financial System is outlined. The system is designed to produce various management and accounting reports needed to maintain control of SWRL operational and financial activities. Included in the document are descriptions of the various types of system…

  15. The ASTRO-1 preliminary design review coupled load analysis

    NASA Technical Reports Server (NTRS)

    Mcghee, D. S.

    1984-01-01

    Results of the ASTRO-1 preliminary design review coupled loads analysis are presented. The M6.0Y Generic Shuttle mathematical models were used. Internal accelerations, interface forces, relative displacements, and net e.g., accelerations were recovered for two ASTRO-1 payloads in a tandem configuration. Twenty-seven load cases were computed and summarized. Load exceedences were found and recommendations made.

  16. Supervisory control of remote manipulation: A preliminary evaluation

    NASA Technical Reports Server (NTRS)

    Starr, G. P.

    1981-01-01

    A system for supervisory control is described, and preliminary results are presented. Supervisory control, where control is traded between man and computer, offers benefits in the control of a remote manipulator. The system has the potential to accomplish sophisticated tasks. It is indicated that supervisory control yields lower task completion times and is preferred over manual control.

  17. Could spot urine analysis of calcium and uric acid help predict density of urinary stone in computerized tomography? A preliminary study.

    PubMed

    Demiray, Özay; Cüce, Ferhat; Çevik, Erdem; Çataloğlu, Berkay; Kalemci, Serdar

    2016-08-01

    This research studies if Hounsfield density of urinary stone can be predicted without computerized tomography (CT) caused by because increased radiation exposure in follow-up of patients. The records of patients with renal or ureteral stone were analyzed retrospectively for the time period between November 2013 and April 2014. The inclusion criteria defined were: no multiple stones; stone size ≥3 mm; presence of renal and ureteral stones; absence of staghorn stone. All CT images were assessed in abdominal windows by a single radiologist. Hounsfield Unit (HU) value of CT was used to interpret the density of the stone. The density of the stone was measured in the longest axis of the stone center (core) and the edges (periphery) of each stone. Biochemical analysis of spot urine calcium (Ca) and uric acid (UA) was done at the time of diagnosis. Correlation and linear regression analysis was performed. Forty patients were included the study and median age of patients is 22 (IQR 21-28). Since the unit was a military hospital, most patients admitted to hospital were young male conscripts with low median age. It has been found that spot urine uric acid and uric acid/Ca ratio is associated with stone density as HU (P=0.004, P<0.001). Although predictive value appeared low, linear regression model statistically predicted stone density as HU (P<0.001 R2=0.32). Stone size has proved to be positively correlated with stone density (P<0.001). Despite the predictive value of urine analysis model is low, it may be considered to predict HU attenuation of stone. Spot urine analysis of calcium and uric acid may be helpful for both diagnosis and follow-up. We believe that controlled studies with larger patient populations will provide further insights into this issue.

  18. Automated CPX support system preliminary design phase

    NASA Technical Reports Server (NTRS)

    Bordeaux, T. A.; Carson, E. T.; Hepburn, C. D.; Shinnick, F. M.

    1984-01-01

    The development of the Distributed Command and Control System (DCCS) is discussed. The development of an automated C2 system stimulated the development of an automated command post exercise (CPX) support system to provide a more realistic stimulus to DCCS than could be achieved with the existing manual system. An automated CPX system to support corps-level exercise was designed. The effort comprised four tasks: (1) collecting and documenting user requirements; (2) developing a preliminary system design; (3) defining a program plan; and (4) evaluating the suitability of the TRASANA FOURCE computer model.

  19. Preliminary Results from the Application of Automated Adjoint Code Generation to CFL3D

    NASA Technical Reports Server (NTRS)

    Carle, Alan; Fagan, Mike; Green, Lawrence L.

    1998-01-01

    This report describes preliminary results obtained using an automated adjoint code generator for Fortran to augment a widely-used computational fluid dynamics flow solver to compute derivatives. These preliminary results with this augmented code suggest that, even in its infancy, the automated adjoint code generator can accurately and efficiently deliver derivatives for use in transonic Euler-based aerodynamic shape optimization problems with hundreds to thousands of independent design variables.

  20. Validation of an Instrument To Measure Dental Students' Use of, Knowledge about, and Attitudes towards Computers.

    ERIC Educational Resources Information Center

    Schleyer, Titus K. L.; Torres-Urquidy, Humberto; Straja, Sorin

    2001-01-01

    Conducted a measurement study to validate a preliminary survey for dental students which contained five subscales: computer use, information resource use, computer knowledge, capabilities of computer systems, and effects of computers on dental practice. Found that all survey scales except computer use were unidimensional; computer use required a…

  1. Preliminary results of DISTO

    NASA Astrophysics Data System (ADS)

    Bedfer, Y.

    1998-05-01

    DISTO is a spectrometer experiment installed at Saturne in Saclay to study strangeness production in p¯p reactions. It has entered its production phase in the second semester of 1996 and is to complete it by the time Saturne closes at the end of 1997. Preliminary results bearing on the two main items of its physics program. viz. polarization in associated hyperon production and OZ1 rule assessment in vector meson production, and obtained at 2.85 GeV are presented.

  2. Ruiz Volcano: Preliminary report

    NASA Astrophysics Data System (ADS)

    Ruiz Volcano, Colombia (4.88°N, 75.32°W). All times are local (= GMT -5 hours).An explosive eruption on November 13, 1985, melted ice and snow in the summit area, generating lahars that flowed tens of kilometers down flank river valleys, killing more than 20,000 people. This is history's fourth largest single-eruption death toll, behind only Tambora in 1815 (92,000), Krakatau in 1883 (36,000), and Mount Pelée in May 1902 (28,000). The following briefly summarizes the very preliminary and inevitably conflicting information that had been received by press time.

  3. Environmental Survey preliminary report

    SciTech Connect

    Not Available

    1988-04-01

    This report presents the preliminary findings from the first phase of the Environmental Survey of the United States Department of Energy (DOE) Sandia National Laboratories conducted August 17 through September 4, 1987. The objective of the Survey is to identify environmental problems and areas of environmental risk associated with Sandia National Laboratories-Albuquerque (SNLA). The Survey covers all environmental media and all areas of environmental regulation. It is being performed in accordance with the DOE Environmental Survey Manual. This phase of the Survey involves the review of existing site environmental data, observations of the operations carried on at SNLA, and interviews with site personnel. 85 refs., 49 figs., 48 tabs.

  4. [Use of Computers in Introductory Physics Teaching.

    ERIC Educational Resources Information Center

    Merrill, John R.

    This paper presents some of the preliminary results of Project COEXIST at Dartmouth College, an NSF sponsored project to investigate ways to use computers in introductory physics and mathematics teaching. Students use the computer in a number of ways on homework, on individual projects, and in the laboratory. Students write their own programs,…

  5. Preliminary ISIS users manual

    NASA Technical Reports Server (NTRS)

    Grantham, C.

    1979-01-01

    The Interactive Software Invocation (ISIS), an interactive data management system, was developed to act as a buffer between the user and host computer system. The user is provided by ISIS with a powerful system for developing software or systems in the interactive environment. The user is protected from the idiosyncracies of the host computer system by providing such a complete range of capabilities that the user should have no need for direct access to the host computer. These capabilities are divided into four areas: desk top calculator, data editor, file manager, and tool invoker.

  6. Preliminary decommissioning study reports

    SciTech Connect

    Horton, J.R.

    1984-09-01

    This six large gunite storage tanks considered as a group is one of approximately 76 facilities currently managed by the Oak Ridge National Laboratories (ORNL) Surplus Facilities Management Program (SFMP). This program, as part of the Department of Energy (DOE) national SFMP, is responsible for the maintenance and surveillance and the final decommissioning of radioactively contaminated surplus ORNL facilities. A long-range planning effort is being conducted that will outline the scope and objectives of the ORNL program and establish decommissioning priorities based on health and safety concerns, budget constraints, and other programmatic constraints. In support of this SFMP planning activity, preliminary engineering assessments are being conducted for each of the ORNL surplus facilities currently managed under the program. These efforts are designed to: (1) provide an initial assessment of the potential decommissioning alternatives, (2) choose a preferred alternative and provide a justification of the decommissioning plan, including cost and schedule estimates. This report presents the results of the preliminary decommission study for the six gunite storage tanks.

  7. Computers and Computer Cultures.

    ERIC Educational Resources Information Center

    Papert, Seymour

    1981-01-01

    Instruction using computers is viewed as different from most other approaches to education, by allowing more than right or wrong answers, by providing models for systematic procedures, by shifting the boundary between formal and concrete processes, and by influencing the development of thinking in many new ways. (MP)

  8. Recent advances toward preclinical and clinical translation of photoacoustic tomography: a review

    NASA Astrophysics Data System (ADS)

    Upputuri, Paul Kumar; Pramanik, Manojit

    2017-04-01

    Photoacoustic imaging is an emerging hybrid imaging modality that can provide multicontrast, multiscale imaging of biological features ranging from organelles to organs. The three major embodiments of photoacoustic imaging are microscopy, endoscopy, and computed tomography. Photoacoustic tomography (PAT) or photoacoustic computed tomography allows deep-tissue imaging, and hence it is more suitable for whole body preclinical/clinical imaging applications. Due to fast-growing laser technology and ultrasound detector technology, PAT is evolving rapidly, leading to a quicker translation into clinical trials. We review the recent developments of PAT systems and their applications in preclinical and clinical practices.

  9. Computer Engineers.

    ERIC Educational Resources Information Center

    Moncarz, Roger

    2000-01-01

    Looks at computer engineers and describes their job, employment outlook, earnings, and training and qualifications. Provides a list of resources related to computer engineering careers and the computer industry. (JOW)

  10. Computer Engineers.

    ERIC Educational Resources Information Center

    Moncarz, Roger

    2000-01-01

    Looks at computer engineers and describes their job, employment outlook, earnings, and training and qualifications. Provides a list of resources related to computer engineering careers and the computer industry. (JOW)

  11. Computer Music

    NASA Astrophysics Data System (ADS)

    Cook, Perry R.

    This chapter covers algorithms, technologies, computer languages, and systems for computer music. Computer music involves the application of computers and other digital/electronic technologies to music composition, performance, theory, history, and the study of perception. The field combines digital signal processing, computational algorithms, computer languages, hardware and software systems, acoustics, psychoacoustics (low-level perception of sounds from the raw acoustic signal), and music cognition (higher-level perception of musical style, form, emotion, etc.).

  12. Computer Applications Planning. A Guide to Planning and Implementing a District-Wide Computer Program.

    ERIC Educational Resources Information Center

    Mojkowski, Charles

    Designed to help school districts move from exploring the use of computers in the classroom to the comprehensive planning and development of computer education programs, this guide is organized around five steps essential to the process of developing a district program. Phase 1 includes the following preliminary activities involved in planning for…

  13. Computer Music

    NASA Astrophysics Data System (ADS)

    Cook, Perry

    This chapter covers algorithms, technologies, computer languages, and systems for computer music. Computer music involves the application of computers and other digital/electronic technologies to music composition, performance, theory, history, and perception. The field combines digital signal processing, computational algorithms, computer languages, hardware and software systems, acoustics, psychoacoustics (low-level perception of sounds from the raw acoustic signal), and music cognition (higher-level perception of musical style, form, emotion, etc.). Although most people would think that analog synthesizers and electronic music substantially predate the use of computers in music, many experiments and complete computer music systems were being constructed and used as early as the 1950s.

  14. Optical coherence tomography: a non-invasive technique applied to conservation of paintings

    NASA Astrophysics Data System (ADS)

    Liang, Haida; Gomez Cid, Marta; Cucu, Radu; Dobre, George; Kudimov, Boris; Pedro, Justin; Saunders, David; Cupitt, John; Podoleanu, Adrian

    2005-06-01

    It is current practice to take tiny samples from a painting to mount and examine in cross-section under a microscope. However, since conservation practice and ethics limit sampling to a minimum and to areas along cracks and edges of paintings, which are often unrepresentative of the whole painting, results from such analyses cannot be taken as representative of a painting as a whole. Recently in a preliminary study, we have demonstrated that near-infrared Optical Coherence Tomography (OCT) can be used directly on paintings to examine the cross-section of paint and varnish layers without contact and the need to take samples. OCT is an optical interferometric technique developed for in vivo imaging of the eye and biological tissues; it is essentially a scanning Michelson's interferometer with a "broad-band" source that has the spatial coherence of a laser. The low temporal coherence and high spatial concentration of the source are the keys to high depth resolution and high sensitivity 3D imaging. The technique is non-invasive and non-contact with a typical working distance of 2 cm. This non-invasive technique enables cross-sections to be examined anywhere on a painting. In this paper, we will report new results on applying near-infrared en-face OCT to paintings conservation and extend the application to the examination of underdrawings, drying processes, and quantitative measurements of optical properties of paint and varnish layers.

  15. Optical computer motherboards

    NASA Astrophysics Data System (ADS)

    Jannson, Tomasz P.; Xu, Guoda; Bartha, John M.; Gruntman, Michael A.

    1997-09-01

    In this paper, we investigate the application of precision plastic optics into a communication/computer sub-system, such as a hybrid computer motherboard. We believe that using optical waveguides for next-generation computer motherboards can provide a high performance alternative for present multi-layer printed circuit motherboards. In response to this demand, we suggest our novel concept of a hybrid motherboard based on an internal-fiber-coupling (IFC) wavelength-division-multiplexing (WDM) optical backplane. The IFC/WDM backplane provides dedicated Tx/Rx connections, and applies low-cost, high-performance components, including CD LDs, GRIN plastic fibers, molding housing, and nonimaging optics connectors. Preliminary motherboard parameters are: speed 100 MHz/100 m, or 1 GHz/10 m; fiber loss approximately 0.01 dB/m; almost zero fan-out/fan-in optical power loss, and eight standard wavelength channels. The proposed hybrid computer motherboard, based on innovative optical backplane technology, should solve low-speed, low-parallelism bottlenecks in present electric computer motherboards.

  16. Preliminary Analysis of Photoreading

    NASA Technical Reports Server (NTRS)

    McNamara, Danielle S.

    2000-01-01

    The purpose of this project was to provide a preliminary analysis of a reading strategy called PhotoReading. PhotoReading is a technique developed by Paul Scheele that claims to increase reading rate to 25,000 words per minute (Scheele, 1993). PhotoReading itself involves entering a "relaxed state" and looking at, but not reading, each page of a text for a brief moment (about I to 2 seconds). While this technique has received attention in the popular press, there had been no objective examinations of the technique's validity. To examine the effectiveness of PhotoReading, the principal investigator (i.e., trainee) participated in a PhotoReading workshop to learn the technique. Parallel versions of two standardized and three experimenter-created reading comprehension tests were administered to the trainee and an expert user of the PhotoReading technique to compare the use of normal reading strategies and the PhotoReading technique by both readers. The results for all measures yielded no benefits of using the PhotoReading technique. The extremely rapid reading rates claimed by PhotoReaders were not observed; indeed, the reading rates were generally comparable to those for normal reading. Moreover, the PhotoReading expert generally showed an increase in reading time when using the PhotoReading technique in comparison to when using normal reading strategies to process text. This increase in reading time when PhotoReading was accompanied by a decrease in text comprehension.

  17. Preliminary decommissioning study reports

    SciTech Connect

    Horton, J.R.

    1984-09-01

    Twenty-one low-level liquid radioactive waste collection and storage tanks are part of approximately 76 facilities currently managed by the ORNL Surplus Facilities Management Program (SFMP). This program, as part of the DOE national SFMP, is responsible for the maintenance and surveillance and the final decommissioning of radioactively contaminated surplus ORNL facilities. A long range planning effort is being conducted that will outline the scope and objectives of the ORNL program and establish decommissioning priorities based on health and safety concerns, budget constraints, and other programmatic constraints. In support of this SFMP planning activity, preliminary engineering assessments are being conducted for each of the ORNL surplus facilities currently managed under the program. These efforts are designed to: (1) provide an initial assessment of the potential decommissioning alternatives; (2) choose a preferred alternative and provide a justification of the decommissioning plan, including cost and schedule estimates. D D of eight of the nine groups of surplus tanks are considered in this report.

  18. Preliminary reference Earth model

    NASA Astrophysics Data System (ADS)

    Dziewonski, Adam M.; Anderson, Don L.

    1981-06-01

    A large data set consisting of about 1000 normal mode periods, 500 summary travel time observations, 100 normal mode Q values, mass and moment of inertia have been inverted to obtain the radial distribution of elastic properties, Q values and density in the Earth's interior. The data set was supplemented with a special study of 12 years of ISC phase data which yielded an additional 1.75 × 10 6 travel time observations for P and S waves. In order to obtain satisfactory agreement with the entire data set we were required to take into account anelastic dispersion. The introduction of transverse isotropy into the outer 220 km of the mantle was required in order to satisfy the shorter period fundamental toroidal and spheroidal modes. This anisotropy also improved the fit of the larger data set. The horizontal and vertical velocities in the upper mantle differ by 2-4%, both for P and S waves. The mantle below 220 km is not required to be anisotropic. Mantle Rayleigh waves are surprisingly sensitive to compressional velocity in the upper mantle. High S n velocities, low P n velocities and a pronounced low-velocity zone are features of most global inversion models that are suppressed when anisotropy is allowed for in the inversion. The Preliminary Reference Earth Model, PREM, and auxiliary tables showing fits to the data are presented.

  19. Stardust Interstellar Preliminary Examination (ISPE)

    NASA Astrophysics Data System (ADS)

    Westphal, A. J.; Allen, C.; Bajt, S.; Basset, R.; Bastien, R.; Bechtel, H.; Bleuet, P.; Borg, J.; Brenker, F.; Bridges, J.; Brownlee, D. E.; Burchell, M.; Burghammer, M.; Butterworth, A. L.; Cloetens, P.; Cody, G.; Ferroir, T.; Floss, C.; Flynn, G. J.; Frank, D.; Gainsforth, Z.; Grün, E.; Hoppe, P.; Kearsley, A.; Lemelle, L.; Leroux, H.; Lettieri, R.; Marchant, W.; Mendez, B.; Nittler, L. R.; Ogliore, R.; Postberg, F.; Sandford, S. A.; Schmitz, S.; Silversmit, G.; Simionovici, A.; Srama, R.; Stadermann, F. J.; Stephan, T.; Stroud, R. M.; Susini, J.; Sutton, S.; Trieloff, M.; Tsou, P.; Tsuchiyama, A.; Tyliczszak, T.; Vekemans, B.; Vincze, L.; Warren, J.; Zolensky, M. E.

    2009-03-01

    The Stardust Interstellar Preliminary Examination (ISPE) is a three-year effort to characterize the Stardust interstellar dust collection and collector using non-destructive techniques. We summarize the status of the ISPE.

  20. Cooling Computers.

    ERIC Educational Resources Information Center

    Birken, Marvin N.

    1967-01-01

    Numerous decisions must be made in the design of computer air conditioning, each determined by a combination of economics, physical, and esthetic characteristics, and computer requirements. Several computer air conditioning systems are analyzed--(1) underfloor supply and overhead return, (2) underfloor plenum and overhead supply with computer unit…

  1. Pygmalion's Computer.

    ERIC Educational Resources Information Center

    Peelle, Howard A.

    Computers have undoubtedly entered the educational arena, mainly in the areas of computer-assisted instruction (CAI) and artificial intelligence, but whether educators should embrace computers and exactly how they should use them are matters of great debate. The use of computers in support of educational administration is widely accepted.…

  2. Cooling Computers.

    ERIC Educational Resources Information Center

    Birken, Marvin N.

    1967-01-01

    Numerous decisions must be made in the design of computer air conditioning, each determined by a combination of economics, physical, and esthetic characteristics, and computer requirements. Several computer air conditioning systems are analyzed--(1) underfloor supply and overhead return, (2) underfloor plenum and overhead supply with computer unit…

  3. Computer Literacy.

    ERIC Educational Resources Information Center

    South Carolina State Dept. of Education, Columbia.

    This self-instructional manual presents basic information about computers and their capabilities in a series of lessons, each of which contains a list of learner objectives and a series of true-false self-check exercises. The lessons cover: (1) what a computer is and what it can do, and the reasons why computers are used; (2) computer types and…

  4. Time-lapse electrical resistivity tomography: a powerful tool for landslide monitoring?

    NASA Astrophysics Data System (ADS)

    Perrone, A.

    2011-12-01

    The extreme rainfall events and the quick snowmelt occurrences play an important role in the triggering of the landslides. The occurrence of one of these factors can determine the variation of water content in the first layers of the subsoil and as a consequence a quick soil saturation inducing both an increase in pore-water pressures and the overloaded of the slopes progressively collapsing. The electrical resistivity, self-potential, electromagnetic induction and GPR methods can be considered as the most appropriate for assessing the presence of water in the underground. Such methods allow us to study the behavior of water content over much wider and deeper areas than those offered by traditional methods (thermo-gravimetric, tensiometric, TDR, etc) based on spot measures and concerning small volumes. In particular, the Electrical Resistivity Tomography (ERT), which has already proved to be a powerful tool both for the geometrical reconstruction of a landslide body (location of sliding surface, estimation of the thickness of the slide material) and the individuation of high water content areas, can be considered as an alternative tool to be employed for a qualitative and quantitative water content monitoring in the first layers of the subsoil. Indeed, time-lapse 2D ERT can be tested in order to gather information on the temporal and spatial patterns of water infiltration processes and water content variation. This work reports the preliminary results from a new prototype system planned to obtain time-lapse 2D ERTs, TDR and precipitation measurements in two landslide areas located in the Southern Apennine chain (Italy). The system was planned with the aim to estimate the variation of the resistivity parameter on a long period considering the water content variation, the rain water infiltration and the seasonal changes. The prototype system, linked to a pc used for storing data and managing the time interval acquisition, consists of: a resistivimeter connected to a

  5. Applied potential tomography: a new non-invasive technique for assessing gastric function.

    PubMed

    Mangnall, Y F; Baxter, A J; Avill, R; Bird, N C; Brown, B H; Barber, D C; Seagar, A D; Johnson, A G; Read, N W

    1987-01-01

    Applied potential tomography is a new, non-invasive technique that yields sequential images of the resistivity of gastric contents after subjects have ingested a liquid or semi-solid meal. This study validates the technique as a means of measuring gastric emptying. Experiments in vitro showed an excellent correlation between measurements of resistivity and either the square of the radius of a glass rod or the volume of water in a spherical balloon when both were placed in an oval tank containing saline. Altering the lateral position of the rod in the tank did not alter the values obtained. Images of abdominal resistivity were also directly correlated with the volume of air in a gastric balloon. Profiles of gastric emptying of liquid meals obtained using APT were very similar to those obtained using scintigraphy or dye dilution techniques provided that acid secretion was inhibited by cimetidine. Profiles of emptying of a mashed potato meal using APT were also very similar to those obtained by scintigraphy. Measurements of the emptying of a liquid meal from the stomach were reproducible if acid secretion was inhibited by cimetidine. Thus, APT is an accurate and reproducible method of measuring gastric emptying of liquids and particulate food. It is inexpensive, well tolerated, easy to use and ideally suited for multiple studies in patients, even those who are pregnant. A preliminary study is also presented that assesses the technique as a means of measuring gastric acid secretion. Comparison of resistivity changes with measured acid secretion following the injection of pentagastrin shows good correlations. APT might offer a non-invasive alternative to the use of a nasogastric tube and acid collection.

  6. Preliminary development of an intelligent computer assistant for engine monitoring

    NASA Technical Reports Server (NTRS)

    Disbrow, James D.; Duke, Eugene L.; Ray, Ronald J.

    1989-01-01

    As part of the F-18 high-angle-of-attack vehicle program, an AI method was developed for the real time monitoring of the propulsion system and for the identification of recovery procedures for the F404 engine. The aim of the development program is to provide enhanced flight safety and to reduce the duties of the propulsion engineers. As telemetry data is received, the results are continually displayed in a number of different color graphical formats. The system makes possible the monitoring of the engine state and the individual parameters. Anomaly information is immediately displayed to the engineer.

  7. Preliminary development of an intelligent computer assistant for engine monitoring

    NASA Technical Reports Server (NTRS)

    Disbrow, James D.; Duke, Eugene L.; Ray, Ronald J.

    1989-01-01

    As part of the F-18 high-angle-of-attack vehicle program, an AI method has been developed for the real-time monitoring of the propulsion system and for the identification of recovery procedures for the F404 engine. The aim of the development program is to provide enhanced flight safety and to reduce the duties of the propulsion engineers. As telemetry data is received, the results are continually displayed in a number of different color graphical formats. The system makes possible the monitoring of the engine state and the individual parameters. Anomaly information is immediately displayed to the engineer.

  8. Preliminary evaluation of ultra-high pitch computed tomography enterography.

    PubMed

    Hardie, Andrew D; Horst, Nicole D; Mayes, Nicholas

    2012-12-01

    CT enterography (CTE) is a valuable tool in the management of patients with inflammatory bowel disease. Reducing imaging time, reduced motion artifacts, and decreased radiation exposure are important goals for optimizing CTE examinations. To assess the potential impact of new CT technology (ultra-high pitch CTE) for the ability to reduce scan time and also potentially reduce radiation exposure while maintaining image quality. This retrospective study compared 13 patients who underwent ultra-high pitch CTE with 25 patients who underwent routine CTE on the same CT scanner with identical radiation emission settings. Total scan time and radiation exposure were recorded for each patient. Image quality was assessed by measurement of image noise and also qualitatively by two independent observers. Total scan time was significantly lower for patients who underwent ultra-high pitch CTE (2.1 s ± 0.2) than by routine CTE (18.6 s ± 0.9) (P < 0.0001). The mean radiation exposure for ultra-high pitch CTE was also significantly lower (10.1 mGy ± 1.0) than routine CTE (15.8 mGy ± 4.5) (P < 0.0001). No significant difference in image noise was found between ultra-high pitch CTE (16.0 HU ± 2.5) and routine CTE (15.5 HU ± 3.7) (P > 0.74). There was also no significant difference in image quality noted by either of the two readers. Ultra-high pitch CTE can be performed more rapidly than standard CTE and offers the potential for radiation exposure reduction while maintaining image quality.

  9. A Computer Program for the Preliminary Design of Contrarotating Propellers

    DTIC Science & Technology

    1975-12-01

    Burri. L.C. and Emerson, A., "P; opeller Cavitation: Further Tests on 16-Ihch Pirpeller Modbls in the Kings College Cavitation rhnneli," Transactions...6C (K 1)=AQ(Lo WFLOAT (K) 9C(9, 1)0.0 1(9f 1) =000 00 60 Lr29 J=1!3-L 60 8D(Jqi)= BD (J+,It)4BC(J+iql) 00 61 L=199 DO 62 1=2,8 00 62 L=299 K:L-i 6

  10. Synthesis, Preliminary Bioevaluation and Computational Analysis of Caffeic Acid Analogues

    PubMed Central

    Liu, Zhiqian; Fu, Jianjun; Shan, Lei; Sun, Qingyan; Zhang, Weidong

    2014-01-01

    A series of caffeic acid amides were designed, synthesized and evaluated for anti-inflammatory activity. Most of them exhibited promising anti-inflammatory activity against nitric oxide (NO) generation in murine macrophage RAW264.7 cells. A 3D pharmacophore model was created based on the biological results for further structural optimization. Moreover, predication of the potential targets was also carried out by the PharmMapper server. These amide analogues represent a promising class of anti-inflammatory scaffold for further exploration and target identification. PMID:24857914

  11. Trusted Computing Exemplar: Trusted Distribution Plan - Preliminary Design

    DTIC Science & Technology

    2014-12-12

    be analyzed for these characteristics. Lifecycle activities ensure that the product reflects the intent to ensure that the product is trustworthy and...Machinery control systems, MCS, life cycle security, high assurance, system security, trustworthy systems 16. SECURITY CLASSIFICATION OF: 17...that the product is trustworthy and that vigorous efforts have been made to ensure the absence of unspecified functionality, whether accidental or

  12. 2-D Fused Image Reconstruction approach for Microwave Tomography: a theoretical assessment using FDTD Model.

    PubMed

    Bindu, G; Semenov, S

    2013-01-01

    This paper describes an efficient two-dimensional fused image reconstruction approach for Microwave Tomography (MWT). Finite Difference Time Domain (FDTD) models were created for a viable MWT experimental system having the transceivers modelled using thin wire approximation with resistive voltage sources. Born Iterative and Distorted Born Iterative methods have been employed for image reconstruction with the extremity imaging being done using a differential imaging technique. The forward solver in the imaging algorithm employs the FDTD method of solving the time domain Maxwell's equations with the regularisation parameter computed using a stochastic approach. The algorithm is tested with 10% noise inclusion and successful image reconstruction has been shown implying its robustness.

  13. Bacterial Identification Using Light Scattering Measurements: a Preliminary Report

    NASA Technical Reports Server (NTRS)

    Wilkins, J. R.

    1971-01-01

    The light scattering properties of single bacterial cells were examined as a possible means of identification. Three species were studied with streptococcus faecalis exhibiting a unique pattern; the light-scattering traces for staphylococcus aureus and escherichia coli were quite similar although differences existed. Based on preliminary investigations, the light scattering approach appeared promising with additional research needed to include a wide variety of bacterial species, computer capability to handle and analyze data, and expansion of light scattering theory to include bacterial cells.

  14. Preliminary heavy-light decay constants from the MILC Collaboration

    SciTech Connect

    Bernard, C.

    1994-12-01

    Preliminary results from the MILC Collaboration for f{sub B}, f{sub B{sub s}}, f{sub D}, f{sub D{sub s}} and their ratios are presented. We compute in the quenched approximation at {beta} = 6.3, 6.0 and 5.7 with Wilson light quarks and static and Wilson heavy quarks. We attempt to quantify all systematic errors other than quenching.

  15. Bacterial Identification Using Light Scattering Measurements: a Preliminary Report

    NASA Technical Reports Server (NTRS)

    Wilkins, J. R.

    1971-01-01

    The light scattering properties of single bacterial cells were examined as a possible means of identification. Three species were studied with streptococcus faecalis exhibiting a unique pattern; the light-scattering traces for staphylococcus aureus and escherichia coli were quite similar although differences existed. Based on preliminary investigations, the light scattering approach appeared promising with additional research needed to include a wide variety of bacterial species, computer capability to handle and analyze data, and expansion of light scattering theory to include bacterial cells.

  16. Research in computational fluid dynamics

    NASA Technical Reports Server (NTRS)

    Murman, Earll M.

    1987-01-01

    The numerical integration of quasi-one-dimensional unsteady flow problems which involve finite rate chemistry are discussed, and are expressed in terms of conservative form Euler and species conservation equations. Hypersonic viscous calculations for delta wing geometries is also examined. The conical Navier-Stokes equations model was selected in order to investigate the effects of viscous-inviscid interations. The more complete three-dimensional model is beyond the available computing resources. The flux vector splitting method with van Leer's MUSCL differencing is being used. Preliminary results were computed for several conditions.

  17. Computational dosimetry

    SciTech Connect

    Siebert, B.R.L.; Thomas, R.H.

    1996-01-01

    The paper presents a definition of the term ``Computational Dosimetry`` that is interpreted as the sub-discipline of computational physics which is devoted to radiation metrology. It is shown that computational dosimetry is more than a mere collection of computational methods. Computational simulations directed at basic understanding and modelling are important tools provided by computational dosimetry, while another very important application is the support that it can give to the design, optimization and analysis of experiments. However, the primary task of computational dosimetry is to reduce the variance in the determination of absorbed dose (and its related quantities), for example in the disciplines of radiological protection and radiation therapy. In this paper emphasis is given to the discussion of potential pitfalls in the applications of computational dosimetry and recommendations are given for their avoidance. The need for comparison of calculated and experimental data whenever possible is strongly stressed.

  18. Computational Toxicology

    EPA Science Inventory

    Computational toxicology’ is a broad term that encompasses all manner of computer-facilitated informatics, data-mining, and modeling endeavors in relation to toxicology, including exposure modeling, physiologically based pharmacokinetic (PBPK) modeling, dose-response modeling, ...

  19. Computer Recreations.

    ERIC Educational Resources Information Center

    Dewdney, A. K.

    1989-01-01

    Reviews the performance of computer programs for writing poetry and prose, including MARK V. SHANEY, MELL, POETRY GENERATOR, THUNDER THOUGHT, and ORPHEUS. Discusses the writing principles of the programs. Provides additional information on computer magnification techniques. (YP)

  20. Computational Toxicology

    EPA Science Inventory

    Computational toxicology’ is a broad term that encompasses all manner of computer-facilitated informatics, data-mining, and modeling endeavors in relation to toxicology, including exposure modeling, physiologically based pharmacokinetic (PBPK) modeling, dose-response modeling, ...

  1. Quantum computing

    PubMed Central

    Li, Shu-Shen; Long, Gui-Lu; Bai, Feng-Shan; Feng, Song-Lin; Zheng, Hou-Zhi

    2001-01-01

    Quantum computing is a quickly growing research field. This article introduces the basic concepts of quantum computing, recent developments in quantum searching, and decoherence in a possible quantum dot realization. PMID:11562459

  2. Cloud Computing

    SciTech Connect

    Pete Beckman and Ian Foster

    2009-12-04

    Chicago Matters: Beyond Burnham (WTTW). Chicago has become a world center of "cloud computing." Argonne experts Pete Beckman and Ian Foster explain what "cloud computing" is and how you probably already use it on a daily basis.

  3. Library Computing.

    ERIC Educational Resources Information Center

    Library Journal, 1985

    1985-01-01

    This special supplement to "Library Journal" and "School Library Journal" includes articles on technological dependency, promise of computers for reluctant readers, copyright and database downloading, access to neighborhood of Mister Rogers, library acquisitions, circulating personal computers, "microcomputeritis,"…

  4. Parallel computation

    NASA Astrophysics Data System (ADS)

    Huberman, Bernardo A.

    1989-11-01

    This paper reviews three different aspects of parallel computation which are useful for physics. The first part deals with special architectures for parallel computing (SIMD and MIMD machines) and their differences, with examples of their uses. The second section discusses the speedup that can be achieved in parallel computation and the constraints generated by the issues of communication and synchrony. The third part describes computation by distributed networks of powerful workstations without global controls and the issues involved in understanding their behavior.

  5. Parallel Computing in SCALE

    SciTech Connect

    DeHart, Mark D; Williams, Mark L; Bowman, Stephen M

    2010-01-01

    The SCALE computational architecture has remained basically the same since its inception 30 years ago, although constituent modules and capabilities have changed significantly. This SCALE concept was intended to provide a framework whereby independent codes can be linked to provide a more comprehensive capability than possible with the individual programs - allowing flexibility to address a wide variety of applications. However, the current system was designed originally for mainframe computers with a single CPU and with significantly less memory than today's personal computers. It has been recognized that the present SCALE computation system could be restructured to take advantage of modern hardware and software capabilities, while retaining many of the modular features of the present system. Preliminary work is being done to define specifications and capabilities for a more advanced computational architecture. This paper describes the state of current SCALE development activities and plans for future development. With the release of SCALE 6.1 in 2010, a new phase of evolutionary development will be available to SCALE users within the TRITON and NEWT modules. The SCALE (Standardized Computer Analyses for Licensing Evaluation) code system developed by Oak Ridge National Laboratory (ORNL) provides a comprehensive and integrated package of codes and nuclear data for a wide range of applications in criticality safety, reactor physics, shielding, isotopic depletion and decay, and sensitivity/uncertainty (S/U) analysis. Over the last three years, since the release of version 5.1 in 2006, several important new codes have been introduced within SCALE, and significant advances applied to existing codes. Many of these new features became available with the release of SCALE 6.0 in early 2009. However, beginning with SCALE 6.1, a first generation of parallel computing is being introduced. In addition to near-term improvements, a plan for longer term SCALE enhancement

  6. Computer Starters!

    ERIC Educational Resources Information Center

    Instructor, 1983

    1983-01-01

    Instructor's Computer-Using Teachers Board members give practical tips on how to get a classroom ready for a new computer, introduce students to the machine, and help them learn about programing and computer literacy. Safety, scheduling, and supervision requirements are noted. (PP)

  7. Computer Literacy.

    ERIC Educational Resources Information Center

    San Marcos Unified School District, CA.

    THE FOLLOWING IS THE FULL TEXT OF THIS DOCUMENT: After viewing many computer-literacy programs, we believe San Marcos Junior High School has developed a unique program which will truly develop computer literacy. Our hope is to give all students a comprehensive look at computers as they go through their two years here. They will not only learn the…

  8. Distributed Computing.

    ERIC Educational Resources Information Center

    Ryland, Jane N.

    1988-01-01

    The microcomputer revolution, in which small and large computers have gained tremendously in capability, has created a distributed computing environment. This circumstance presents administrators with the opportunities and the dilemmas of choosing appropriate computing resources for each situation. (Author/MSE)

  9. Computer Literacy.

    ERIC Educational Resources Information Center

    San Marcos Unified School District, CA.

    THE FOLLOWING IS THE FULL TEXT OF THIS DOCUMENT: After viewing many computer-literacy programs, we believe San Marcos Junior High School has developed a unique program which will truly develop computer literacy. Our hope is to give all students a comprehensive look at computers as they go through their two years here. They will not only learn the…

  10. Distributed Computing.

    ERIC Educational Resources Information Center

    Ryland, Jane N.

    1988-01-01

    The microcomputer revolution, in which small and large computers have gained tremendously in capability, has created a distributed computing environment. This circumstance presents administrators with the opportunities and the dilemmas of choosing appropriate computing resources for each situation. (Author/MSE)

  11. Parallel computers

    SciTech Connect

    Treveaven, P.

    1989-01-01

    This book presents an introduction to object-oriented, functional, and logic parallel computing on which the fifth generation of computer systems will be based. Coverage includes concepts for parallel computing languages, a parallel object-oriented system (DOOM) and its language (POOL), an object-oriented multilevel VLSI simulator using POOL, and implementation of lazy functional languages on parallel architectures.

  12. Children's Computers.

    ERIC Educational Resources Information Center

    Samaras, Anastasia P.

    1996-01-01

    Suggests that teachers and social context determine what young children acquire from computer experiences. Provides anecdotes of teachers working with children who are using a computer program to complete a picture puzzle. The computer allowed teachers to present a problem, witness children's cognitive capabilities, listen to their metacognitive…

  13. Tomography: A window on the role of sulfur in the structure of micrometeorites

    NASA Astrophysics Data System (ADS)

    Taylor, Susan; Jones, Keith W.; Herzog, Gregory F.; Hornig, Claire E.

    2011-10-01

    To determine the role played by sulfides in the formation of vesicles and FeNi metal beads, we mapped the locations and tabulated the numbers of sulfides, metal beads, and vesicles in 1583 sectioned micrometeorites (MMs) using conventional microscopy and in 190 whole MMs using synchrotron computed microtomography (SCMT). Both the section and the SCMT images show that sulfides melt, coalesce, and migrate to the MMs surface. The decomposition of sulfides may occur during all these stages. Given the sulfide morphologies and compositions that we see in section, we think the breakdown of Ni sulfides produces the FeNi beads. The SCMT images show that metal beads are common in melted MMs, >50% have them. Vesicles in porphyritic and scoriaceous MMs are also probably formed as sulfides decompose. Not only do sulfides abut the vesicles but also the temperatures at which sulfides decompose overlap those at which MM surfaces first melt and temporarily seal, suggesting that S gases could produce most of these vesicles. As the vesicle shapes and patterns of distribution differ among MM classes, tomography can be used to nondestructively screen for specific types of MMs. Tomography is a powerful tool for visualizing the three-dimensional distribution of metal beads, sulfides, mean densities, and vesicles in MMs.

  14. Reproducibility of Tear Meniscus Measurement by Fourier-Domain Optical Coherence Tomography: A Pilot Study

    PubMed Central

    Zhou, Sheng; Li, Yan; Lu, Ake Tzu-Hui; Liu, Pengfei; Tang, Maolong; Yiu, Samuel C.; Huang, David

    2009-01-01

    BACKGROUND AND OBJECTIVE To study the reproducibility of tear meniscus measurement with high-speed high-resolution Fourier-domain optical coherence tomography (FD-OCT). PATIENTS AND METHODS Twenty normal participants were enrolled in this prospective study. The lower tear meniscus in the right eye of each subject was imaged by vertical scans centered on the inferior cornea and the lower eyelid using an FD-OCT system (RTVue; Optovue, Inc., Fremont, CA) with a corneal adaptor. The system performs 26,000 axial scans per second and has a 5-micron axial resolution. Each subject was examined at two visits 30 to 60 days apart. Each eye was scanned twice on each visit. The scans were taken 2 seconds after a blink. The lower meniscus height, depth, and cornea-meniscus angle were measured with a computer caliper. The cross-sectional area was calculated using a two-triangle approximation. RESULTS The between-visits coefficient of variation was 17.5%, 18.0%, 35.5%, and 12.2% for meniscus height, depth, area, and angle, respectively. The intraclass correlations for these parameters were 0.605, 0.558, 0.567, and 0.367, respectively. CONCLUSION FD-OCT measures lower tear meniscus dimensions and area with higher between-visits reproducibility than previous OCT instruments. FD-OCT may be a useful way to measure dry eye severity and treatment effectiveness. PMID:19772266

  15. Angiofil-mediated visualization of the vascular system by microcomputed tomography: a feasibility study.

    PubMed

    Grabherr, Silke; Hess, Andreas; Karolczak, Marek; Thali, Michael J; Friess, Sebastian D; Kalender, Willi A; Dirnhofer, Richard; Djonov, Valentin

    2008-07-01

    Visualization of the vascular systems of organs or of small animals is important for an assessment of basic physiological conditions, especially in studies that involve genetically manipulated mice. For a detailed morphological analysis of the vascular tree, it is necessary to demonstrate the system in its entirety. In this study, we present a new lipophilic contrast agent, Angiofil, for performing postmortem microangiography by using microcomputed tomography. The new contrast agent was tested in 10 wild-type mice. Imaging of the vascular system revealed vessels down to the caliber of capillaries, and the digital three-dimensional data obtained from the scans allowed for virtual cutting, amplification, and scaling without destroying the sample. By use of computer software, parameters such as vessel length and caliber could be quantified and remapped by color coding onto the surface of the vascular system. The liquid Angiofil is easy to handle and highly radio-opaque. Because of its lipophilic abilities, it is retained intravascularly, hence it facilitates virtual vessel segmentation, and yields an enduring signal which is advantageous during repetitive investigations, or if samples need to be transported from the site of preparation to the place of actual analysis, respectively. These characteristics make Angiofil a promising novel contrast agent; when combined with microcomputed tomography, it has the potential to turn into a powerful method for rapid vascular phenotyping.

  16. Stardust Interstellar Preliminary Examination

    NASA Astrophysics Data System (ADS)

    Westphal, A.; Stardust Interstellar Preliminary Examation Team: http://www. ssl. berkeley. edu/~westphal/ISPE/

    2011-12-01

    A. J. Westphal, C. Allen, A. Ansari, S. Bajt, R. S. Bastien, H. A. Bechtel, J. Borg, F. E. Brenker, J. Bridges, D. E. Brownlee, M. Burchell, M. Burghammer, A. L. Butterworth, A. M. Davis, P. Cloetens, C. Floss, G. Flynn, D. Frank, Z. Gainsforth, E. Grün, P. R. Heck, J. K. Hillier, P. Hoppe, G. Huss, J. Huth, B. Hvide, A. Kearsley, A. J. King, B. Lai, J. Leitner, L. Lemelle, H. Leroux, R. Lettieri, W. Marchant, L. R. Nittler, R. Ogliore, F. Postberg, M. C. Price, S. A. Sandford, J.-A. Sans Tresseras, T. Schoonjans, S. Schmitz, G. Silversmit, A. Simionovici, V. A. Solé, R. Srama, T. Stephan, V. Sterken, J. Stodolna, R. M. Stroud, S. Sutton, M. Trieloff, P. Tsou, A. Tsuchiyama, T. Tyliszczak, B. Vekemans, L. Vincze, D. Zevin, M. E. Zolensky, >29,000 Stardust@home dusters ISPE author affiliations are at http://www.ssl.berkeley.edu/~westphal/ISPE/. In 2000 and 2002, a ~0.1m2 array of aerogel tiles and alumi-num foils onboard the Stardust spacecraft was exposed to the interstellar dust (ISD) stream for an integrated time of 200 days. The exposure took place in interplanetary space, beyond the orbit of Mars, and thus was free of the ubiquitous orbital debris in low-earth orbit that precludes effective searches for interstellar dust there. Despite the long exposure of the Stardust collector, <<100 ISD particles are expected to have been captured. The particles are thought to be ~1μm or less in size, and the total ISD collection is probably <10-6 by mass of the collection of cometary dust parti-cles captured in the Stardust cometary dust collector from the coma of the Jupiter-family comet Wild 2. Thus, although the first solid sample from the local interstellar medium is clearly of high interest, the diminutive size of the particles and the low numbers of particles present daunting challenges. Nevertheless, six recent developments have made a Preliminary Examination (PE) of this sample practical: (1) rapid automated digital optical scanning microscopy for three

  17. Portable Computer

    NASA Technical Reports Server (NTRS)

    1985-01-01

    SPOC, a navigation monitoring computer used by NASA in a 1983 mission, was a modification of a commercial computer called GRiD Compass, produced by GRiD Systems Corporation. SPOC was chosen because of its small size, large storage capacity, and high processing speed. The principal modification required was a fan to cool the computer. SPOC automatically computes position, orbital paths, communication locations, etc. Some of the modifications were adapted for commercial applications. The computer is presently used in offices for conferences, for on-site development, and by the army as part of a field communications systems.

  18. PRELIMINARY DESIGN ANALYSIS OF AXIAL FLOW TURBINES

    NASA Technical Reports Server (NTRS)

    Glassman, A. J.

    1994-01-01

    A computer program has been developed for the preliminary design analysis of axial-flow turbines. Rapid approximate generalized procedures requiring minimum input are used to provide turbine overall geometry and performance adequate for screening studies. The computations are based on mean-diameter flow properties and a stage-average velocity diagram. Gas properties are assumed constant throughout the turbine. For any given turbine, all stages, except the first, are specified to have the same shape velocity diagram. The first stage differs only in the value of inlet flow angle. The velocity diagram shape depends upon the stage work factor value and the specified type of velocity diagram. Velocity diagrams can be specified as symmetrical, zero exit swirl, or impulse; or by inputting stage swirl split. Exit turning vanes can be included in the design. The 1991 update includes a generalized velocity diagram, a more flexible meanline path, a reheat model, a radial component of velocity, and a computation of free-vortex hub and tip velocity diagrams. Also, a loss-coefficient calibration was performed to provide recommended values for airbreathing engine turbines. Input design requirements include power or pressure ratio, mass flow rate, inlet temperature and pressure, and rotative speed. The design variables include inlet and exit diameters, stator angle or exit radius ratio, and number of stages. Gas properties are input as gas constant, specific heat ratio, and viscosity. The program output includes inlet and exit annulus dimensions, exit temperature and pressure, total and static efficiencies, flow angles, blading angles, and last stage absolute and relative Mach numbers. This program is written in FORTRAN 77 and can be ported to any computer with a standard FORTRAN compiler which supports NAMELIST. It was originally developed on an IBM 7000 series computer running VM and has been implemented on IBM PC computers and compatibles running MS-DOS under Lahey FORTRAN, and

  19. Computer Jet-Engine-Monitoring System

    NASA Technical Reports Server (NTRS)

    Disbrow, James D.; Duke, Eugene L.; Ray, Ronald J.

    1992-01-01

    "Intelligent Computer Assistant for Engine Monitoring" (ICAEM), computer-based monitoring system intended to distill and display data on conditions of operation of two turbofan engines of F-18, is in preliminary state of development. System reduces burden on propulsion engineer by providing single display of summary information on statuses of engines and alerting engineer to anomalous conditions. Effective use of prior engine-monitoring system requires continuous attention to multiple displays.

  20. Computer Jet-Engine-Monitoring System

    NASA Technical Reports Server (NTRS)

    Disbrow, James D.; Duke, Eugene L.; Ray, Ronald J.

    1992-01-01

    "Intelligent Computer Assistant for Engine Monitoring" (ICAEM), computer-based monitoring system intended to distill and display data on conditions of operation of two turbofan engines of F-18, is in preliminary state of development. System reduces burden on propulsion engineer by providing single display of summary information on statuses of engines and alerting engineer to anomalous conditions. Effective use of prior engine-monitoring system requires continuous attention to multiple displays.

  1. Computer software.

    PubMed

    Rosenthal, L E

    1986-10-01

    Software is the component in a computer system that permits the hardware to perform the various functions that a computer system is capable of doing. The history of software and its development can be traced to the early nineteenth century. All computer systems are designed to utilize the "stored program concept" as first developed by Charles Babbage in the 1850s. The concept was lost until the mid-1940s, when modern computers made their appearance. Today, because of the complex and myriad tasks that a computer system can perform, there has been a differentiation of types of software. There is software designed to perform specific business applications. There is software that controls the overall operation of a computer system. And there is software that is designed to carry out specialized tasks. Regardless of types, software is the most critical component of any computer system. Without it, all one has is a collection of circuits, transistors, and silicone chips.

  2. Computer sciences

    NASA Technical Reports Server (NTRS)

    Smith, Paul H.

    1988-01-01

    The Computer Science Program provides advanced concepts, techniques, system architectures, algorithms, and software for both space and aeronautics information sciences and computer systems. The overall goal is to provide the technical foundation within NASA for the advancement of computing technology in aerospace applications. The research program is improving the state of knowledge of fundamental aerospace computing principles and advancing computing technology in space applications such as software engineering and information extraction from data collected by scientific instruments in space. The program includes the development of special algorithms and techniques to exploit the computing power provided by high performance parallel processors and special purpose architectures. Research is being conducted in the fundamentals of data base logic and improvement techniques for producing reliable computing systems.

  3. A Computer-Based Dietary Counseling System.

    ERIC Educational Resources Information Center

    Slack, Warner V.; And Others

    1976-01-01

    The preliminary trial of a program in which principles of patient-computer dialogue have been applied to dietary counseling is described. The program was designed to obtain historical information from overweight patients and to provide instruction and guidance regarding dietary behavior. Beginning with a teaching sequence, 25 non-overweight…

  4. Computer Programming by Kindergarten Children Using LOGO.

    ERIC Educational Resources Information Center

    Munro-Mavrias, Sandra

    Conservation ability, spatial motor ability, age, and gender were used as predictive variables in a study of 26 kindergarten children's computer programming ability. A preliminary pilot study with first graders had suggested that programming success was related to the ability to reverse thought processes. In both studies, children were taught to…

  5. High-resolution global tomography: A full-wave technique for forward and inverse modeling

    NASA Astrophysics Data System (ADS)

    Nissen-Meyer, Tarje; Sigloch, Karin; Fournier, Alexandre

    2010-05-01

    In recent years, seismology has greatly benefitted from significant progress in digital data collection and processing, accurate numerical methods for wave propagation, and high-performance computing to explore crucial scales of interest in both data and model spaces. We will present a full-wave technique to address the seismic forward and inverse problem at the global scale, with a specific focus on diffracted waves in the lowermost mantle: Our 2D spectral-element method tackles 3D wave propagation through spherically symmetric background models down to seismic frequencies of 1 Hz and delivers the wavefields necessary to construct sensitivity kernels. This specific approach distinguishes itself from the adjoint method in that it requires no knowledge about data structure or observables at the time of forward modeling by means of storing entire reference space-time wavefields. To obtain a direct view of the interconnection between surface displacements and earth structure, we examine the time-dependent sensitivity of the seismic signal to 3D model perturbations. Being highly sensitive to such parameters as epicentral distance, earthquake radiation pattern, depth, frequency, receiver components and time windows, this effort suggests criteria for data selection to optimally illuminate a specific region within the earth. As shown with core-diffracted P-waves, we measure and model our observables (e.g. traveltimes, amplitudes) in multiple-frequency passbands, thereby increasing robustness of the inverse problem and path coverage. This allows us to selectively draw only upon frequency bands with high signal-to-noise ratio. We discuss the selection and usability of data for such a Pdiff tomographic setting, coverage maps and target regions. We also touch upon the validity of a 1D reference model and quantify the applicability range of the first-order Born approximation.

  6. Synframe: a preliminary report.

    PubMed

    Aebi, M; Steffen, T

    2000-02-01

    Both endoscopic lumbar spinal surgery and the non-standardized and unstable retractor systems for the lumbar spine presently on the market have disadvantages and limitations in relation to the minimally invasive surgical concept, which have been gradually recognized in the last few years. In an attempt to resolve some of these issues, we have developed a highly versatile retractor system, which allows access to and surgery at the lumbar, thoracic and even cervical spine. This retractor system - Synframe - is based on a ring concept allowing 360 degrees access to a surgical opening in anterior as well as posterior surgery. The ring is concentrically laid over the surgical opening for the approach and is used as a carrier for retractor arms, which are instrumented with either different sizes or types of blades and/or different sizes of Hohmann hooks. In posterior surgery, nerve root retractors can also be installed. This ring also functions as a carrier for fiberoptic illumination devices and different sizes of endoscopes, used to transmit the surgical procedure out of the depth of the surgical exposure for both teaching purposes and for the surgical team when it has no longer direct visual access to the procedure. The ring is stable, being fixed onto the operating table, allowing precise minimally open approaches and surgical procedures under direct vision with optimal illumination. This ring system also opens perspectives for an integrated minimally open surgical concept, where the ring may be used as a reference platform in computer-navigated surgery.

  7. Heterogeneous concurrent computing with exportable services

    NASA Technical Reports Server (NTRS)

    Sunderam, Vaidy

    1995-01-01

    Heterogeneous concurrent computing, based on the traditional process-oriented model, is approaching its functionality and performance limits. An alternative paradigm, based on the concept of services, supporting data driven computation, and built on a lightweight process infrastructure, is proposed to enhance the functional capabilities and the operational efficiency of heterogeneous network-based concurrent computing. TPVM is an experimental prototype system supporting exportable services, thread-based computation, and remote memory operations that is built as an extension of and an enhancement to the PVM concurrent computing system. TPVM offers a significantly different computing paradigm for network-based computing, while maintaining a close resemblance to the conventional PVM model in the interest of compatibility and ease of transition Preliminary experiences have demonstrated that the TPVM framework presents a natural yet powerful concurrent programming interface, while being capable of delivering performance improvements of upto thirty percent.

  8. Concentrating solar collector subsystem: Preliminary design package

    NASA Technical Reports Server (NTRS)

    1977-01-01

    Preliminary design data are presented for a concentrating solar collector including an attitude controller. Provided are schedules, technical status, all documents required for preliminary design, and other program activities.

  9. Computational psychiatry

    PubMed Central

    Montague, P. Read; Dolan, Raymond J.; Friston, Karl J.; Dayan, Peter

    2013-01-01

    Computational ideas pervade many areas of science and have an integrative explanatory role in neuroscience and cognitive science. However, computational depictions of cognitive function have had surprisingly little impact on the way we assess mental illness because diseases of the mind have not been systematically conceptualized in computational terms. Here, we outline goals and nascent efforts in the new field of computational psychiatry, which seeks to characterize mental dysfunction in terms of aberrant computations over multiple scales. We highlight early efforts in this area that employ reinforcement learning and game theoretic frameworks to elucidate decision-making in health and disease. Looking forwards, we emphasize a need for theory development and large-scale computational phenotyping in human subjects. PMID:22177032

  10. Computational aerothermodynamics

    NASA Technical Reports Server (NTRS)

    Deiwert, George S.; Green, Michael J.

    1987-01-01

    Computational aerothermodynamics (CAT) has in the past contributed to the understanding of real-gas flows encountered by hypervelocity reentry vehicles. With advances in computational fluid dynamics, in the modeling of high temperature phenomena, and in computer capability, CAT is an enabling technology for the design of many future space vehicles. An overview of the current capabilities of CAT is provided by describing available methods and their applications. Technical challenges that need to be met are discussed.

  11. Computer Software.

    ERIC Educational Resources Information Center

    Kay, Alan

    1984-01-01

    Discusses the nature and development of computer software. Programing, programing languages, types of software (including dynamic spreadsheets), and software of the future are among the topics considered. (JN)

  12. 18 CFR 806.11 - Preliminary consultations.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... COMMISSION REVIEW AND APPROVAL OF PROJECTS Application Procedure § 806.11 Preliminary consultations. (a) Any... Commission staff for an informal discussion of preliminary plans for the proposed project. To facilitate preliminary consultations, it is suggested that the project sponsor provide a general description of...

  13. 18 CFR 806.11 - Preliminary consultations.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... COMMISSION REVIEW AND APPROVAL OF PROJECTS Application Procedure § 806.11 Preliminary consultations. (a) Any... Commission staff for an informal discussion of preliminary plans for the proposed project. To facilitate preliminary consultations, it is suggested that the project sponsor provide a general description of...

  14. 40 CFR 161.170 - Preliminary analysis.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Preliminary analysis. (a) If the product is produced by an integrated system, the applicant must provide a preliminary analysis of each technical grade of active ingredient contained in the product to identify all... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Preliminary analysis. 161.170 Section...

  15. 45 CFR 150.217 - Preliminary determination.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 45 Public Welfare 1 2010-10-01 2010-10-01 false Preliminary determination. 150.217 Section 150.217... Are Failing To Substantially Enforce HIPAA Requirements § 150.217 Preliminary determination. If, at... designees). (b) Notifies the State of CMS's preliminary determination that the State has failed to...

  16. Computer-aided visual assessment in mine planning and design

    Treesearch

    Michael Hatfield; A. J. LeRoy Balzer; Roger E. Nelson

    1979-01-01

    A computer modeling technique is described for evaluating the visual impact of a proposed surface mine located within the viewshed of a national park. A computer algorithm analyzes digitized USGS baseline topography and identifies areas subject to surface disturbance visible from the park. Preliminary mine and reclamation plan information is used to describe how the...

  17. Communication and Computability: The Case of Alan Mathison Turing.

    ERIC Educational Resources Information Center

    Chesebro, James W.

    1993-01-01

    Provides a preliminary examination of the relationships which exist between the disciplines of communication and computer science. Isolates the original principles which determined the development of computer science. Suggests how these early formation principles had and continue to have on the study of communication. Focuses on the seminal role…

  18. Communication and Computability: The Case of Alan Mathison Turing.

    ERIC Educational Resources Information Center

    Chesebro, James W.

    1993-01-01

    Provides a preliminary examination of the relationships which exist between the disciplines of communication and computer science. Isolates the original principles which determined the development of computer science. Suggests how these early formation principles had and continue to have on the study of communication. Focuses on the seminal role…

  19. Preliminary microfluidic simulations for immersion lithography

    NASA Astrophysics Data System (ADS)

    Wei, Alexander C.; Nellis, Greg F.; Abdo, Amr Y.; Engelstad, Roxann L.; Chen, Cheng-Fu; Switkes, Michael; Rothschild, Mordechai

    2003-06-01

    The premise behind immersion lithography is to improve the resolution for optical lithography technology by increasing the index of refraction in the space between the final projection lens of an exposure system and the device wafer. This is accomplished through the insertion of a high index liquid in place of the low index air that currently fills the gap. The fluid management system must reliably fill the lens-wafer gap with liquid, maintain the fill under the lens throughout the entire wafer exposure process, and ensure that no bubbles are entrained during filling or scanning. This paper presents a preliminary analysis of the fluid flow characteristics of a liquid between the lens and the wafer in immersion lithography. The objective of this feasibility study was to identify liquid candidates that meet both optical and specific fluid mechanical requirements. The mechanics of the filling process was analyzed to simplify the problem and identify those fluid properties and system parameters that affect the process. Two-dimensional computational fluid dynamics (CFD) models of the fluid between the lens and the wafer were developed for simulating the process. The CFD simulations were used to investigate two methods of liquid deposition. In the first, a liquid is dispensed onto the wafer as a "puddle" and then the wafer and liquid move under the lens. This is referred to as passive filling. The second method involves the use of liquid jets in close proximity to the edge of the lens and is referred to as active filling. Numerical simulations of passive filling included a parametric study of the key dimensionless group influencing the filling process and an investigation of the effects of the fluid/wafer and fluid/lens contact angles and wafer direction. The model results are compared with experimental measurements. For active filling, preliminary simulation results characterized the influence of the jets on fluid flow.

  20. Computing Life

    ERIC Educational Resources Information Center

    National Institute of General Medical Sciences (NIGMS), 2009

    2009-01-01

    Computer advances now let researchers quickly search through DNA sequences to find gene variations that could lead to disease, simulate how flu might spread through one's school, and design three-dimensional animations of molecules that rival any video game. By teaming computers and biology, scientists can answer new and old questions that could…

  1. Computer Recreations.

    ERIC Educational Resources Information Center

    Dewdney, A. K.

    1989-01-01

    Discussed are three examples of computer graphics including biomorphs, Truchet tilings, and fractal popcorn. The graphics are shown and the basic algorithm using multiple iteration of a particular function or mathematical operation is described. An illustration of a snail shell created by computer graphics is presented. (YP)

  2. I, Computer

    ERIC Educational Resources Information Center

    Barack, Lauren

    2005-01-01

    What child hasn't chatted with friends through a computer? But chatting with a computer? Some Danish scientists have literally put a face on their latest software program, bringing to virtual life storyteller Hans Christian Andersen, who engages users in actual conversations. The digitized Andersen resides at the Hans Christian Andersen Museum in…

  3. Computer Insecurity.

    ERIC Educational Resources Information Center

    Wilson, David L.

    1994-01-01

    College administrators recently appealed to students and faculty to change their computer passwords after security experts announced that tens of thousands had been stolen by computer hackers. Federal officials are investigating. Such attacks are not uncommon, but the most effective solutions are either inconvenient or cumbersome. (MSE)

  4. Computational Pathology

    PubMed Central

    Louis, David N.; Feldman, Michael; Carter, Alexis B.; Dighe, Anand S.; Pfeifer, John D.; Bry, Lynn; Almeida, Jonas S.; Saltz, Joel; Braun, Jonathan; Tomaszewski, John E.; Gilbertson, John R.; Sinard, John H.; Gerber, Georg K.; Galli, Stephen J.; Golden, Jeffrey A.; Becich, Michael J.

    2016-01-01

    Context We define the scope and needs within the new discipline of computational pathology, a discipline critical to the future of both the practice of pathology and, more broadly, medical practice in general. Objective To define the scope and needs of computational pathology. Data Sources A meeting was convened in Boston, Massachusetts, in July 2014 prior to the annual Association of Pathology Chairs meeting, and it was attended by a variety of pathologists, including individuals highly invested in pathology informatics as well as chairs of pathology departments. Conclusions The meeting made recommendations to promote computational pathology, including clearly defining the field and articulating its value propositions; asserting that the value propositions for health care systems must include means to incorporate robust computational approaches to implement data-driven methods that aid in guiding individual and population health care; leveraging computational pathology as a center for data interpretation in modern health care systems; stating that realizing the value proposition will require working with institutional administrations, other departments, and pathology colleagues; declaring that a robust pipeline should be fostered that trains and develops future computational pathologists, for those with both pathology and non-pathology backgrounds; and deciding that computational pathology should serve as a hub for data-related research in health care systems. The dissemination of these recommendations to pathology and bioinformatics departments should help facilitate the development of computational pathology. PMID:26098131

  5. Cloud Computing

    DTIC Science & Technology

    2009-11-12

    Eucalyptus Systems • Provides an open-source application that can be used to implement a cloud computing environment on a datacenter • Trying to establish an...edgeplatform.html • Amazon Elastic Compute Cloud (EC2): http://aws.amazon.com/ec2/ • Amazon Simple Storage Solution (S3): http://aws.amazon.com/s3/ • Eucalyptus

  6. Computer Insecurity.

    ERIC Educational Resources Information Center

    Wilson, David L.

    1994-01-01

    College administrators recently appealed to students and faculty to change their computer passwords after security experts announced that tens of thousands had been stolen by computer hackers. Federal officials are investigating. Such attacks are not uncommon, but the most effective solutions are either inconvenient or cumbersome. (MSE)

  7. Computer News

    ERIC Educational Resources Information Center

    Science Activities: Classroom Projects and Curriculum Ideas, 2007

    2007-01-01

    This article presents several news stories about computers and technology. (1) Applied Science Associates of Narragansett, Rhode Island is providing computer modeling technology to help locate the remains to the USS Bonhomme Richard, which sank in 1779 after claiming a Revolutionary War victory. (2) Whyville, the leading edu-tainment virtual world…

  8. Computer News

    ERIC Educational Resources Information Center

    Science Activities: Classroom Projects and Curriculum Ideas, 2007

    2007-01-01

    This article presents several news stories about computers and technology. (1) Applied Science Associates of Narragansett, Rhode Island is providing computer modeling technology to help locate the remains to the USS Bonhomme Richard, which sank in 1779 after claiming a Revolutionary War victory. (2) Whyville, the leading edu-tainment virtual world…

  9. Computational astrophysics

    NASA Technical Reports Server (NTRS)

    Miller, Richard H.

    1987-01-01

    Astronomy is an area of applied physics in which unusually beautiful objects challenge the imagination to explain observed phenomena in terms of known laws of physics. It is a field that has stimulated the development of physical laws and of mathematical and computational methods. Current computational applications are discussed in terms of stellar and galactic evolution, galactic dynamics, and particle motions.

  10. Computer Recreations.

    ERIC Educational Resources Information Center

    Dewdney, A. K.

    1989-01-01

    Discussed are three examples of computer graphics including biomorphs, Truchet tilings, and fractal popcorn. The graphics are shown and the basic algorithm using multiple iteration of a particular function or mathematical operation is described. An illustration of a snail shell created by computer graphics is presented. (YP)

  11. I, Computer

    ERIC Educational Resources Information Center

    Barack, Lauren

    2005-01-01

    What child hasn't chatted with friends through a computer? But chatting with a computer? Some Danish scientists have literally put a face on their latest software program, bringing to virtual life storyteller Hans Christian Andersen, who engages users in actual conversations. The digitized Andersen resides at the Hans Christian Andersen Museum in…

  12. Grid Computing

    NASA Astrophysics Data System (ADS)

    Foster, Ian

    2001-08-01

    The term "Grid Computing" refers to the use, for computational purposes, of emerging distributed Grid infrastructures: that is, network and middleware services designed to provide on-demand and high-performance access to all important computational resources within an organization or community. Grid computing promises to enable both evolutionary and revolutionary changes in the practice of computational science and engineering based on new application modalities such as high-speed distributed analysis of large datasets, collaborative engineering and visualization, desktop access to computation via "science portals," rapid parameter studies and Monte Carlo simulations that use all available resources within an organization, and online analysis of data from scientific instruments. In this article, I examine the status of Grid computing circa 2000, briefly reviewing some relevant history, outlining major current Grid research and development activities, and pointing out likely directions for future work. I also present a number of case studies, selected to illustrate the potential of Grid computing in various areas of science.

  13. Computer Graphics.

    ERIC Educational Resources Information Center

    Halpern, Jeanne W.

    1970-01-01

    Computer graphics have been called the most exciting development in computer technology. At the University of Michigan, three kinds of graphics output equipment are now being used: symbolic printers, line plotters or drafting devices, and cathode-ray tubes (CRT). Six examples are given that demonstrate the range of graphics use at the University.…

  14. Preliminary design studies for the DESCARTES and CIDER codes

    SciTech Connect

    Eslinger, P.W.; Miley, T.B.; Ouderkirk, S.J.; Nichols, W.E.

    1992-12-01

    The Hanford Environmental Dose Reconstruction (HEDR) project is developing several computer codes to model the release and transport of radionuclides into the environment. This preliminary design addresses two of these codes: Dynamic Estimates of Concentrations and Radionuclides in Terrestrial Environments (DESCARTES) and Calculation of Individual Doses from Environmental Radionuclides (CIDER). The DESCARTES code will be used to estimate the concentration of radionuclides in environmental pathways, given the output of the air transport code HATCHET. The CIDER code will use information provided by DESCARTES to estimate the dose received by an individual. This document reports on preliminary design work performed by the code development team to determine if the requirements could be met for Descartes and CIDER. The document contains three major sections: (i) a data flow diagram and discussion for DESCARTES, (ii) a data flow diagram and discussion for CIDER, and (iii) a series of brief statements regarding the design approach required to address each code requirement.

  15. Carbon dioxide reactivity of tumor blood flow as measured by dynamic contrast-enhanced computed tomography: a new treatment protocol for laser thermal therapy

    NASA Astrophysics Data System (ADS)

    Purdie, Thomas G.; Sherar, Michael D.; Fenster, Aaron; Lee, Ting-Yim

    2001-05-01

    The purpose of the current study is to measure the carbon dioxide reactivity of blood flow in VX2 tumor in the rabbit thigh. The carbon dioxide reactivity of the functional parameters was investigated in eight rabbits by changing the ventilation rate in order to manipulate the arterial carbon dioxide tension (PaCO2). In each experiment, functional maps were generated at four PaCO2 levels: normocapnia (PaCO2 equals 40.7 +/- 1.4 mm Hg), hypocapnia (27.1 +/- 2.5 and 33.7 +/- 2.2) and hypercapnia (53.8 +/- 5.2). The carbon dioxide reactivity of tumor blood flow showed significant differences between normocapnia and the two levels of hypocapnia, but not between normocapnia and hypercapnia. The average fractional change of blood flow from normocapnia for the two hypocapnic level was -0.41 +/- 0.06 and -0.29 +/- 0.08, respectively. The ability to reduce blood flow through hypocapnia has significant implications in thermal therapy, as heat dissipation represents a major obstacle which limits the effectiveness of treatment.

  16. Determination of regional lung air volume distribution at mid-tidal breathing from computed tomography: a retrospective study of normal variability and reproducibility

    PubMed Central

    2014-01-01

    Background Determination of regional lung air volume has several clinical applications. This study investigates the use of mid-tidal breathing CT scans to provide regional lung volume data. Methods Low resolution CT scans of the thorax were obtained during tidal breathing in 11 healthy control male subjects, each on two separate occasions. A 3D map of air volume was derived, and total lung volume calculated. The regional distribution of air volume from centre to periphery of the lung was analysed using a radial transform and also using one dimensional profiles in three orthogonal directions. Results The total air volumes for the right and left lungs were 1035 +/− 280 ml and 864 +/− 315 ml, respectively (mean and SD). The corresponding fractional air volume concentrations (FAVC) were 0.680 +/− 0.044 and 0.658 +/− 0.062. All differences between the right and left lung were highly significant (p < 0.0001). The coefficients of variation of repeated measurement of right and left lung air volumes and FAVC were 6.5% and 6.9% and 2.5% and 3.6%, respectively. FAVC correlated significantly with lung space volume (r = 0.78) (p < 0.005). FAVC increased from the centre towards the periphery of the lung. Central to peripheral ratios were significantly higher for the right (0.100 +/− 0.007 SD) than the left (0.089 +/− 0.013 SD) (p < 0.0001). Conclusion A technique for measuring the distribution of air volume in the lung at mid-tidal breathing is described. Mean values and reproducibility are described for healthy male control subjects. Fractional air volume concentration is shown to increase with lung size. PMID:25063729

  17. Malignancy rates and diagnostic performance of the Bosniak classification for the diagnosis of cystic renal lesions in computed tomography - a systematic review and meta-analysis.

    PubMed

    Sevcenco, Sabina; Spick, Claudio; Helbich, Thomas H; Heinz, Gertraud; Shariat, Shahrokh F; Klingler, Hans C; Rauchenwald, Michael; Baltzer, Pascal A

    2017-06-01

    To systematically review the literature on the Bosniak classification system in CT to determine its diagnostic performance to diagnose malignant cystic lesions and the prevalence of malignancy in Bosniak categories. A predefined database search was performed from 1 January 1986 to 18 January 2016. Two independent reviewers extracted data on malignancy rates in Bosniak categories and several covariates using predefined criteria. Study quality was assessed using QUADAS-2. Meta-analysis included data pooling, subgroup analyses, meta-regression and investigation of publication bias. A total of 35 studies, which included 2,578 lesions, were investigated. Data on observer experience, inter-observer variation and technical CT standards were insufficiently reported. The pooled rate of malignancy increased from Bosniak I (3.2 %, 95 % CI 0-6.8, I(2) = 5 %) to Bosniak II (6 %, 95 % CI 2.7-9.3, I(2) = 32 %), IIF (6.7 %, 95 % CI 5-8.4, I(2) = 0 %), III (55.1 %, 95 % CI 45.7-64.5, I(2) = 89 %) and IV (91 %, 95 % CI 87.7-94.2, I(2) = 36). Several study design-related influences on malignancy rates and subsequent diagnostic performance indices were identified. The Bosniak classification is an accurate tool with which to stratify the risk of malignancy in renal cystic lesions. • The Bosniak classification can accurately rule out malignancy. • Specificity remains moderate at 74 % (95 % CI 64-82). • Follow-up examinations should be considered in Bosniak IIF and Bosniak II cysts. • Data on the influence of reader experience and inter-reader variability are insufficient. • Technical CT standards and publication year did not influence diagnostic performance.

  18. Assessment of systolic thickening with thallium-201 ECG-gated single-photon emission computed tomography: A parameter for local left ventricular function

    SciTech Connect

    Mochizuki, T.; Murase, K.; Fujiwara, Y.; Tanada, S.; Hamamoto, K.; Tauxe, W.N. )

    1991-08-01

    The authors measured left ventricular (LV) systolic thickening expressed as a systolic thickening ratio in 28 patients, using 201Tl ECG-gated SPECT. Five normals, 15 patients with prior myocardial infarction, 5 with hypertrophic cardiomyopathy, and 3 with dilated cardiomyopathy were studied. The systolic thickening ratio was calculated as ((end-systolic--end-diastolic pixel counts) divided by end-diastolic pixel counts), using the circumferential profile technique of both end-diastolic and end-systolic short axial images. Functional images of the systolic thickening ratio were also displayed with the bull's-eye method. The mean systolic thickening ratio thus calculated were as follows: normals, 0.53 {plus minus} 0.05 (mean {plus minus} 1 s.d.); non-transmural prior myocardial infarction, 0.33 {plus minus} 0.09; transmural prior myocardial infarction, 0.14 {plus minus} 0.05; hypertrophic cardiomyopathy in relatively nonhypertrophied areas, 0.56 {plus minus} 0.11; hypertrophic cardiomyopathy in hypertrophied areas, 0.23 {plus minus} 0.07; and dilated cardiomyopathy, 0.19 {plus minus} 0.02. The systolic thickening ratio analysis by gated thallium SPECT offers a unique approach for assessing LV function.

  19. Morphology of the Insertions of the Superficial Medial Collateral Ligament and Posterior Oblique Ligament Using 3-Dimensional Computed Tomography: A Cadaveric Study.

    PubMed

    Saigo, Takaaki; Tajima, Goro; Kikuchi, Shuhei; Yan, Jun; Maruyama, Moritaka; Sugawara, Atsushi; Doita, Minoru

    2017-02-01

    To describe the insertions of the superficial medial collateral ligament (sMCL) and posterior oblique ligament (POL) and their related osseous landmarks. Insertions of the sMCL and POL were identified and marked in 22 unpaired human cadaveric knees. The surface area, location, positional relations, and morphology of the sMCL and POL insertions and related osseous structures were analyzed on 3-dimensional images. The femoral insertion of the POL was located 18.3 mm distal to the apex of the adductor tubercle (AT). The femoral insertion of the sMCL was located 21.1 mm distal to the AT and 9.2 mm anterior to the POL. The angle between the femoral axis and femoral insertion of the sMCL was 18.6°, and that between the femoral axis and the POL insertion was 5.1°. The anterior portions of the distal fibers of the POL were attached to the fascia cruris and semimembranosus tendon, whereas the posterior fibers were attached to the posteromedial side of the tibia directly. The tibial insertion of the POL was located just proximal and medial to the superior edge of the semimembranosus groove. The tibial insertion of the sMCL was attached firmly and widely to the tibial crest. The mean linear distances between the tibial insertion of the POL or sMCL and joint line were 5.8 and 49.6 mm, respectively. This study used 3-dimensional images to assess the insertions of the sMCL and POL and their related osseous landmarks. The AT was identified clearly as an osseous landmark of the femoral insertions of the sMCL and POL. The tibial crest and semimembranosus groove served as osseous landmarks of the tibial insertions of the sMCL and POL. By showing further details of the anatomy of the knee, the described findings can assist surgeons in anatomic reconstruction of the sMCL and POL. Copyright © 2016 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.

  20. Computer science concept inventories: past and future

    NASA Astrophysics Data System (ADS)

    Taylor, C.; Zingaro, D.; Porter, L.; Webb, K. C.; Lee, C. B.; Clancy, M.

    2014-10-01

    Concept Inventories (CIs) are assessments designed to measure student learning of core concepts. CIs have become well known for their major impact on pedagogical techniques in other sciences, especially physics. Presently, there are no widely used, validated CIs for computer science. However, considerable groundwork has been performed in the form of identifying core concepts, analyzing student misconceptions, and developing CI assessment questions. Although much of the work has been focused on CS1 and a CI has been developed for digital logic, some preliminary work on CIs is underway for other courses. This literature review examines CI work in other STEM disciplines, discusses the preliminary development of CIs in computer science, and outlines related research in computer science education that contributes to CI development.

  1. Intelligent redundant actuation system requirements and preliminary system design

    NASA Technical Reports Server (NTRS)

    Defeo, P.; Geiger, L. J.; Harris, J.

    1985-01-01

    Several redundant actuation system configurations were designed and demonstrated to satisfy the stringent operational requirements of advanced flight control systems. However, this has been accomplished largely through brute force hardware redundancy, resulting in significantly increased computational requirements on the flight control computers which perform the failure analysis and reconfiguration management. Modern technology now provides powerful, low-cost microprocessors which are effective in performing failure isolation and configuration management at the local actuator level. One such concept, called an Intelligent Redundant Actuation System (IRAS), significantly reduces the flight control computer requirements and performs the local tasks more comprehensively than previously feasible. The requirements and preliminary design of an experimental laboratory system capable of demonstrating the concept and sufficiently flexible to explore a variety of configurations are discussed.

  2. A preliminary design for flight testing the FINDS algorithm

    NASA Technical Reports Server (NTRS)

    Caglayan, A. K.; Godiwala, P. M.

    1986-01-01

    This report presents a preliminary design for flight testing the FINDS (Fault Inferring Nonlinear Detection System) algorithm on a target flight computer. The FINDS software was ported onto the target flight computer by reducing the code size by 65%. Several modifications were made to the computational algorithms resulting in a near real-time execution speed. Finally, a new failure detection strategy was developed resulting in a significant improvement in the detection time performance. In particular, low level MLS, IMU and IAS sensor failures are detected instantaneously with the new detection strategy, while accelerometer and the rate gyro failures are detected within the minimum time allowed by the information generated in the sensor residuals based on the point mass equations of motion. All of the results have been demonstrated by using five minutes of sensor flight data for the NASA ATOPS B-737 aircraft in a Microwave Landing System (MLS) environment.

  3. Mobile Computing for Aerospace Applications

    NASA Technical Reports Server (NTRS)

    Alena, Richard; Swietek, Gregory E. (Technical Monitor)

    1994-01-01

    The use of commercial computer technology in specific aerospace mission applications can reduce the cost and project cycle time required for the development of special-purpose computer systems. Additionally, the pace of technological innovation in the commercial market has made new computer capabilities available for demonstrations and flight tests. Three areas of research and development being explored by the Portable Computer Technology Project at NASA Ames Research Center are the application of commercial client/server network computing solutions to crew support and payload operations, the analysis of requirements for portable computing devices, and testing of wireless data communication links as extensions to the wired network. This paper will present computer architectural solutions to portable workstation design including the use of standard interfaces, advanced flat-panel displays and network configurations incorporating both wired and wireless transmission media. It will describe the design tradeoffs used in selecting high-performance processors and memories, interfaces for communication and peripheral control, and high resolution displays. The packaging issues for safe and reliable operation aboard spacecraft and aircraft are presented. The current status of wireless data links for portable computers is discussed from a system design perspective. An end-to-end data flow model for payload science operations from the experiment flight rack to the principal investigator is analyzed using capabilities provided by the new generation of computer products. A future flight experiment on-board the Russian MIR space station will be described in detail including system configuration and function, the characteristics of the spacecraft operating environment, the flight qualification measures needed for safety review, and the specifications of the computing devices to be used in the experiment. The software architecture chosen shall be presented. An analysis of the

  4. Mobile Computing for Aerospace Applications

    NASA Technical Reports Server (NTRS)

    Alena, Richard; Swietek, Gregory E. (Technical Monitor)

    1994-01-01

    The use of commercial computer technology in specific aerospace mission applications can reduce the cost and project cycle time required for the development of special-purpose computer systems. Additionally, the pace of technological innovation in the commercial market has made new computer capabilities available for demonstrations and flight tests. Three areas of research and development being explored by the Portable Computer Technology Project at NASA Ames Research Center are the application of commercial client/server network computing solutions to crew support and payload operations, the analysis of requirements for portable computing devices, and testing of wireless data communication links as extensions to the wired network. This paper will present computer architectural solutions to portable workstation design including the use of standard interfaces, advanced flat-panel displays and network configurations incorporating both wired and wireless transmission media. It will describe the design tradeoffs used in selecting high-performance processors and memories, interfaces for communication and peripheral control, and high resolution displays. The packaging issues for safe and reliable operation aboard spacecraft and aircraft are presented. The current status of wireless data links for portable computers is discussed from a system design perspective. An end-to-end data flow model for payload science operations from the experiment flight rack to the principal investigator is analyzed using capabilities provided by the new generation of computer products. A future flight experiment on-board the Russian MIR space station will be described in detail including system configuration and function, the characteristics of the spacecraft operating environment, the flight qualification measures needed for safety review, and the specifications of the computing devices to be used in the experiment. The software architecture chosen shall be presented. An analysis of the

  5. Radioactive waste shredding: Preliminary evaluation

    SciTech Connect

    Soelberg, N.R.; Reimann, G.A.

    1994-07-01

    The critical constraints for sizing solid radioactive and mixed wastes for subsequent thermal treatment were identified via a literature review and a survey of shredding equipment vendors. The types and amounts of DOE radioactive wastes that will require treatment to reduce the waste volume, destroy hazardous organics, or immobilize radionuclides and/or hazardous metals were considered. The preliminary steps of waste receipt, inspection, and separation were included because many potential waste treatment technologies have limits on feedstream chemical content, physical composition, and particle size. Most treatment processes and shredding operations require at least some degree of feed material characterization. Preliminary cost estimates show that pretreatment costs per unit of waste can be high and can vary significantly, depending on the processing rate and desired output particle size.

  6. The MUNU experiment : preliminary results

    NASA Astrophysics Data System (ADS)

    Busto, J.; MUNU Collaboration

    2000-06-01

    The MUNU collaboration has built a detector to study overlineνe - e - scattering at low energy. From the results we expect to increase the sensitivity to the neutrino magnetic moment. The detector used, a 1 m 3 T.P.C. surrounded by an anti-Compton scintillator, is running at the Bugey nuclear plant. Some preliminary results will be presented in the following.

  7. Lunar Excavator Preliminary Test Video

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This video shows a preliminary test of the boom and bucket wheel assembly of the lunar excavator prototype developed by the Center for Commercial Applications of Combustion at the Colorado School of Mines in Golden. According to Michael Duke, director for the center, the wheel on the end of the boom can dig up 45.36 kilograms (100 pounds) of dirt each hour which is several times the weight of the entire device.

  8. Lunar Excavator Preliminary Test Video

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This video shows a preliminary test of the boom and bucket wheel assembly of the lunar excavator prototype developed by the Center for Commercial Applications of Combustion at the Colorado School of Mines in Golden. According to Michael Duke, director for the center, the wheel on the end of the boom can dig up 45.36 kilograms (100 pounds) of dirt each hour which is several times the weight of the entire device.

  9. Optical computing.

    NASA Technical Reports Server (NTRS)

    Stroke, G. W.

    1972-01-01

    Applications of the optical computer include an approach for increasing the sharpness of images obtained from the most powerful electron microscopes and fingerprint/credit card identification. The information-handling capability of the various optical computing processes is very great. Modern synthetic-aperture radars scan upward of 100,000 resolvable elements per second. Fields which have assumed major importance on the basis of optical computing principles are optical image deblurring, coherent side-looking synthetic-aperture radar, and correlative pattern recognition. Some examples of the most dramatic image deblurring results are shown.

  10. Optical computing.

    NASA Technical Reports Server (NTRS)

    Stroke, G. W.

    1972-01-01

    Applications of the optical computer include an approach for increasing the sharpness of images obtained from the most powerful electron microscopes and fingerprint/credit card identification. The information-handling capability of the various optical computing processes is very great. Modern synthetic-aperture radars scan upward of 100,000 resolvable elements per second. Fields which have assumed major importance on the basis of optical computing principles are optical image deblurring, coherent side-looking synthetic-aperture radar, and correlative pattern recognition. Some examples of the most dramatic image deblurring results are shown.

  11. Computational gestalts and perception thresholds.

    PubMed

    Desolneux, Agnès; Moisan, Lionel; Morel, Jean-Michel

    2003-01-01

    In 1923, Max Wertheimer proposed a research programme and method in visual perception. He conjectured the existence of a small set of geometric grouping laws governing the perceptual synthesis of phenomenal objects, or "gestalt" from the atomic retina input. In this paper, we review this set of geometric grouping laws, using the works of Metzger, Kanizsa and their schools. In continuation, we explain why the Gestalt theory research programme can be translated into a Computer Vision programme. This translation is not straightforward, since Gestalt theory never addressed two fundamental matters: image sampling and image information measurements. Using these advances, we shall show that gestalt grouping laws can be translated into quantitative laws allowing the automatic computation of gestalts in digital images. From the psychophysical viewpoint, a main issue is raised: the computer vision gestalt detection methods deliver predictable perception thresholds. Thus, we are set in a position where we can build artificial images and check whether some kind of agreement can be found between the computationally predicted thresholds and the psychophysical ones. We describe and discuss two preliminary sets of experiments, where we compared the gestalt detection performance of several subjects with the predictable detection curve. In our opinion, the results of this experimental comparison support the idea of a much more systematic interaction between computational predictions in Computer Vision and psychophysical experiments.

  12. Evolutionary Computing

    SciTech Connect

    Patton, Robert M; Cui, Xiaohui; Jiao, Yu; Potok, Thomas E

    2008-01-01

    The rate at which information overwhelms humans is significantly more than the rate at which humans have learned to process, analyze, and leverage this information. To overcome this challenge, new methods of computing must be formulated, and scientist and engineers have looked to nature for inspiration in developing these new methods. Consequently, evolutionary computing has emerged as new paradigm for computing, and has rapidly demonstrated its ability to solve real-world problems where traditional techniques have failed. This field of work has now become quite broad and encompasses areas ranging from artificial life to neural networks. This chapter focuses specifically on two sub-areas of nature-inspired computing: Evolutionary Algorithms and Swarm Intelligence.

  13. Computer Calculus.

    ERIC Educational Resources Information Center

    Steen, Lynn Arthur

    1981-01-01

    The development of symbolic computer algebra designed to manipulate abstract mathematical expressions is discussed. The ability of this software to mimic the standard patterns of human problem solving represents a major advance toward "true" artificial intelligence. (MP)

  14. Computer Poker

    ERIC Educational Resources Information Center

    Findler, Nicholas V.

    1978-01-01

    This familiar card game has interested mathematicians, economists, and psychologists as a model of decision-making in the real world. It is now serving as a vehicle for investigations in computer science. (Author/MA)

  15. Personal Computers.

    ERIC Educational Resources Information Center

    Toong, Hoo-min D.; Gupta, Amar

    1982-01-01

    Describes the hardware, software, applications, and current proliferation of personal computers (microcomputers). Includes discussions of microprocessors, memory, output (including printers), application programs, the microcomputer industry, and major microcomputer manufacturers (Apple, Radio Shack, Commodore, and IBM). (JN)

  16. Computer Stimulation

    ERIC Educational Resources Information Center

    Moore, John W.; Moore, Elizabeth

    1977-01-01

    Discusses computer simulation approach of Limits to Growth, in which interactions of five variables (population, pollution, resources, food per capita, and industrial output per capita) indicate status of the world. Reviews other books that predict future of the world. (CS)

  17. Quantum Computing

    DTIC Science & Technology

    1998-04-01

    information representation and processing technology, although faster than the wheels and gears of the Charles Babbage computation machine, is still in...the same computational complexity class as the Babbage machine, with bits of information represented by entities which obey classical (non-quantum...nuclear double resonances Charles M Bowden and Jonathan P. Dowling Weapons Sciences Directorate, AMSMI-RD-WS-ST Missile Research, Development, and

  18. LHC Computing

    SciTech Connect

    Lincoln, Don

    2015-07-28

    The LHC is the world’s highest energy particle accelerator and scientists use it to record an unprecedented amount of data. This data is recorded in electronic format and it requires an enormous computational infrastructure to convert the raw data into conclusions about the fundamental rules that govern matter. In this video, Fermilab’s Dr. Don Lincoln gives us a sense of just how much data is involved and the incredible computer resources that makes it all possible.

  19. Computational chemistry

    NASA Technical Reports Server (NTRS)

    Arnold, J. O.

    1987-01-01

    With the advent of supercomputers, modern computational chemistry algorithms and codes, a powerful tool was created to help fill NASA's continuing need for information on the properties of matter in hostile or unusual environments. Computational resources provided under the National Aerodynamics Simulator (NAS) program were a cornerstone for recent advancements in this field. Properties of gases, materials, and their interactions can be determined from solutions of the governing equations. In the case of gases, for example, radiative transition probabilites per particle, bond-dissociation energies, and rates of simple chemical reactions can be determined computationally as reliably as from experiment. The data are proving to be quite valuable in providing inputs to real-gas flow simulation codes used to compute aerothermodynamic loads on NASA's aeroassist orbital transfer vehicles and a host of problems related to the National Aerospace Plane Program. Although more approximate, similar solutions can be obtained for ensembles of atoms simulating small particles of materials with and without the presence of gases. Computational chemistry has application in studying catalysis, properties of polymers, all of interest to various NASA missions, including those previously mentioned. In addition to discussing these applications of computational chemistry within NASA, the governing equations and the need for supercomputers for their solution is outlined.

  20. Computational oncology.

    PubMed

    Lefor, Alan T

    2011-08-01

    Oncology research has traditionally been conducted using techniques from the biological sciences. The new field of computational oncology has forged a new relationship between the physical sciences and oncology to further advance research. By applying physics and mathematics to oncologic problems, new insights will emerge into the pathogenesis and treatment of malignancies. One major area of investigation in computational oncology centers around the acquisition and analysis of data, using improved computing hardware and software. Large databases of cellular pathways are being analyzed to understand the interrelationship among complex biological processes. Computer-aided detection is being applied to the analysis of routine imaging data including mammography and chest imaging to improve the accuracy and detection rate for population screening. The second major area of investigation uses computers to construct sophisticated mathematical models of individual cancer cells as well as larger systems using partial differential equations. These models are further refined with clinically available information to more accurately reflect living systems. One of the major obstacles in the partnership between physical scientists and the oncology community is communications. Standard ways to convey information must be developed. Future progress in computational oncology will depend on close collaboration between clinicians and investigators to further the understanding of cancer using these new approaches.

  1. Chromatin Computation

    PubMed Central

    Bryant, Barbara

    2012-01-01

    In living cells, DNA is packaged along with protein and RNA into chromatin. Chemical modifications to nucleotides and histone proteins are added, removed and recognized by multi-functional molecular complexes. Here I define a new computational model, in which chromatin modifications are information units that can be written onto a one-dimensional string of nucleosomes, analogous to the symbols written onto cells of a Turing machine tape, and chromatin-modifying complexes are modeled as read-write rules that operate on a finite set of adjacent nucleosomes. I illustrate the use of this “chromatin computer” to solve an instance of the Hamiltonian path problem. I prove that chromatin computers are computationally universal – and therefore more powerful than the logic circuits often used to model transcription factor control of gene expression. Features of biological chromatin provide a rich instruction set for efficient computation of nontrivial algorithms in biological time scales. Modeling chromatin as a computer shifts how we think about chromatin function, suggests new approaches to medical intervention, and lays the groundwork for the engineering of a new class of biological computing machines. PMID:22567109

  2. Orbit Determination with Very Short Arcs: Preliminary Orbits and Identifications

    NASA Astrophysics Data System (ADS)

    Milani, A.; Gronchi, G. F.; Knezevic, Z.; Sansaturio, M. E.

    2004-05-01

    When the observation of a new asteroid are not enough to compute an orbit we can represent them with an attributable (two angles and their time derivatives). The undetermined range and range rate span an admissible region of solar system orbits, which can be represented by a set of Virtual Asteroids (VAs) selected by an optimal triangulation (see the presentation by G. Gronchi). The four coordinates of the attributable are the result of a fit and have a covariance matrix. Thus the predictions of future observations have a quasi-product structure (admissible region times confidence ellipsoid), approximated by a triangulation with a confidence ellipsoid for each node. If we have >2 observations we can also estimate the geodetic curvature and the acceleration of the observed path on the celestial sphere. If both are significantly measured they constrain the range and the range rate and may allow to reduce the size of the admissible region. To compute a a preliminary orbit starting from two attributables, for each VA (selected in the admissible region of the first arc) we consider the prediction at the time of the second and its covariance matrix, and we compare them with the attributable of the second arc with its covariance. By using the identification penalty (as in the algorithms for orbit identification) we can select as a preliminary orbit the VAs which fits together both arcs in the 8-dimensional space. Two attributables may not be enough to compute an orbit with convergent differential corrections. The preliminary orbit is used in a constrained differential correction, providing solutions along the Line Of Variations, to be used as second generation VAs to predict the observations at the time of a third arc. In general the identification with a third arc ensures a well determined orbit.

  3. Improving the delineation of hydrocarbon-impacted soils and water through induced polarization (IP) tomographies: a field study at an industrial waste land.

    PubMed

    Deceuster, John; Kaufmann, Olivier

    2012-08-01

    Without a good estimation of samples representativeness, the delineation of the contaminated plume extent and the evaluation of volumes of hydrocarbon-impacted soils may remain difficult. To contribute to this question, a time domain induced polarization (IP) field experiment was conducted on an industrial waste land. Boreholes were drilled to specify the local geological context. Cross-hole seismic tomographies were performed to extend borehole logs and to draw an interpreted geological cross-section. Soil samples taken during drillings were analysed in laboratory. A preliminary survey was conducted to locate the IP profile. The polarization signatures linked to the presence of clayey sediments were filtered out from the data set. Chargeability and resistivity depth soundings were computed and compared to mean concentrations of total organic products to overcome the data support issue between the geophysical models and the spot samples of soils. A logarithmic relation between chargeabilities and smoothed hydrocarbon concentrations in soils was found. Taking into account contaminant's concentration thresholds defined in local codes and regulations allows defining chargeability classes to delineate hotspots on this site. This showed that IP tomography can be an accurate screening methodology. A statistical methodology is proposed to assess the efficiency of the investigation strategy. Copyright © 2012 Elsevier B.V. All rights reserved.

  4. Improving the delineation of hydrocarbon-impacted soils and water through induced polarization (IP) tomographies: A field study at an industrial waste land

    NASA Astrophysics Data System (ADS)

    Deceuster, John; Kaufmann, Olivier

    2012-08-01

    Without a good estimation of samples representativeness, the delineation of the contaminated plume extent and the evaluation of volumes of hydrocarbon-impacted soils may remain difficult. To contribute to this question, a time domain induced polarization (IP) field experiment was conducted on an industrial waste land. Boreholes were drilled to specify the local geological context. Cross-hole seismic tomographies were performed to extend borehole logs and to draw an interpreted geological cross-section. Soil samples taken during drillings were analysed in laboratory. A preliminary survey was conducted to locate the IP profile. The polarization signatures linked to the presence of clayey sediments were filtered out from the data set. Chargeability and resistivity depth soundings were computed and compared to mean concentrations of total organic products to overcome the data support issue between the geophysical models and the spot samples of soils. A logarithmic relation between chargeabilities and smoothed hydrocarbon concentrations in soils was found. Taking into account contaminant's concentration thresholds defined in local codes and regulations allows defining chargeability classes to delineate hotspots on this site. This showed that IP tomography can be an accurate screening methodology. A statistical methodology is proposed to assess the efficiency of the investigation strategy.

  5. Computational Electromagnetic Modeling of SansEC(Trade Mark) Sensors

    NASA Technical Reports Server (NTRS)

    Smith, Laura J.; Dudley, Kenneth L.; Szatkowski, George N.

    2011-01-01

    This paper describes the preliminary effort to apply computational design tools to aid in the development of an electromagnetic SansEC resonant sensor composite materials damage detection system. The computational methods and models employed on this research problem will evolve in complexity over time and will lead to the development of new computational methods and experimental sensor systems that demonstrate the capability to detect, diagnose, and monitor the damage of composite materials and structures on aerospace vehicles.

  6. Preliminary Results of Autotuning GEMM Kernels for the NVIDIA Kepler Architecture- GeForce GTX 680

    SciTech Connect

    Kurzak, Jakub; Luszczek, Pitor; Tomov, Stanimire; Dongarra, Jack

    2012-04-01

    Kepler is the newest GPU architecture from NVIDIA, and the GTX 680 is the first commercially available graphics card based on that architecture. Matrix multiplication is a canonical computational kernel, and often the main target of initial optimization efforts for a new chip. This article presents preliminary results of automatically tuning matrix multiplication kernels for the Kepler architecture using the GTX 680 card.

  7. Optical scattering (TAOS) by tire debris particles: preliminary results

    NASA Astrophysics Data System (ADS)

    Crosta, Giovanni F.; Camatini, Marina C.; Zomer, Simeone; Holler, Stephen; Pan, Yongle; Bhaskara, Praveena; Muangchareon, Pongphisanu; Sung, Changmo; Cencetti, Simone; Regazzoni, Claudia

    2001-03-01

    Tire debris particles from low severity laboratory wear tests have been investigated by the TAOS optical scattering facility at Yale University. The incident wavelength is 532 nm. After the TAOS event some particle samples have been imaged by a scanning electron microscope and microanalyzed. The TAOS intensity patterns recorded within a solid angle in the backward sector have been processed by cluster analysis and compared with the patterns computed by a T-matrix code. Preliminary agreement has been found between TAOS data and the particle models (size, shape, refractive index). The purpose of the investigation is to obtain signatures of the material, based on its TAOS pattern.

  8. Optical scattering (TAOS) by tire debris particles: preliminary results.

    PubMed

    Crosta, G; Camatini, M; Zomer, S; Holler, S; Pan, Y; Bhaskara, P; Muangchareon, P; Sung, C; Cencetti, S; Regazzoni, C

    2001-03-12

    Tire debris particles from low severity laboratory wear tests have been investigated by the TAOS optical scattering facility at Yale University. The incident wavelength is 532 nm. After the TAOS event some particle samples have been imaged by a scanning electron microscope and microanalyzed. The TAOS intensity patterns recorded within a solid angle in the backward sector have been processed by cluster analysis and compared with the patterns computed by a T-matrix code. Preliminary agreement has been found between TAOS data and the particle models (size, shape, refractive index). The purpose of the investigation is to obtain signatures of the material, based on its TAOS pattern.

  9. CALAS: Carpathian laser strainmeter: a project and preliminary results

    NASA Astrophysics Data System (ADS)

    Garoi, F.; Apostol, D.; Damian, V.; Logofătu, P. C.; Ioniţă, B. F.; Lazar, J.; Molesini, G.; Papadopoulos, T.; Ionescu, C.; Ţugui, Andreea

    2008-06-01

    A laser strainmeter for in-situ monitoring of an important actively seismic area of Europe, namely Vrancea region in Romania is proposed. Six groups from four different countries (Romania, Czech Republic, Italy and Greece) with various areas of expertise (e.g. geophysics, lasers, optics, interferometry, and mechanics) are involved in order to sustain the complexity of the project. This paper presents some preliminary laboratory experiments related to measuring relative displacements with a stable interferometer. Displacements of the order of tens to hundreds of nanometers (80 to 285 nm) were measured with uncertainty of +/-1 nm. A computer algorithm was used to process the interferograms.

  10. A preliminary experiment definition for video landmark acquisition and tracking

    NASA Technical Reports Server (NTRS)

    Schappell, R. T.; Tietz, J. C.; Hulstrom, R. L.; Cunningham, R. A.; Reel, G. M.

    1976-01-01

    Six scientific objectives/experiments were derived which consisted of agriculture/forestry/range resources, land use, geology/mineral resources, water resources, marine resources and environmental surveys. Computer calculations were then made of the spectral radiance signature of each of 25 candidate targets as seen by a satellite sensor system. An imaging system capable of recognizing, acquiring and tracking specific generic type surface features was defined. A preliminary experiment definition and design of a video Landmark Acquisition and Tracking system is given. This device will search a 10-mile swath while orbiting the earth, looking for land/water interfaces such as coastlines and rivers.

  11. Preliminary Study for a Tetrahedron Formation: Quality Factors and Visualization

    NASA Technical Reports Server (NTRS)

    Guzman, Jose J.; Schiff, Conrad; Bauer, Frank (Technical Monitor)

    2002-01-01

    Spacecraft flying in tetrahedron formations are excellent for electromagnetic and plasma studies. The quality of the science recorded is strongly affected by the tetrahedron evolution. This paper is a preliminary study on the computation of quality factors and visualization for a formation of four or five satellites. Four of the satellites are arranged geometrically in a tetrahedron shape. If a fifth satellite is present, it is arbitrarily initialized at the geometric center of the tetrahedron. The fifth satellite could act as a collector or as a spare spacecraft. Tetrahedron natural coordinates are employed for the initialization. The natural orbit evolution is visualized in geocentric equatorial inertial and in geocentric solar magnetospheric coordinates.

  12. Prostate elastography: preliminary in vivo results

    NASA Astrophysics Data System (ADS)

    Alam, S. K.; Feleppa, E. J.; Kalisz, A.; Ramchandran, S.; Ennis, R. D.; Lizzi, Frederick L.; Wuu, C.-S.; Ketterling, Jeffrey A.

    2005-04-01

    We report preliminary results from our investigation of in vivo prostate elastography. Fewer than 50% of all prostate cancers are typically visible in current clinical imaging modalities. Elastography displays a map of strain that results when tissue is externally compressed. Thus, elastography is ideal for imaging prostate cancers because they are generally stiffer than the surrounding tissue and stiffer regions usually exhibit lower strain in elastograms. In our study, digital radio-frequency (RF) ultrasound echo data were acquired from prostate-cancer patients undergoing brachytherapy. Seed placement is guided by a transrectal ultrasound (TRUS) probe, which is held in a mechanical fixture. The probe can be moved in XYZ directions and tilted. The probe face, in contact with the rectal wall, is used to apply a compression force to the immediately adjacent prostate. We also used a water-filled (acoustic) coupling balloon to compress the prostate by increasing the water volume inside the balloon. In each scan plane (transverse), we acquired RF data from successive scans at the scanner frame rate as the deformation force on the rectal wall was continuously increased. We computed strain using 1D RF cross-correlation analysis. The compression method based on fixture displacement produced low-noise elastograms that beautifully displayed the prostate architecture and emphasized stiff areas. Balloon-based compression also produced low-noise elastograms. Initial results demonstrate that elastography may be useful in the detection and evaluation of prostate cancers, occult in conventional imaging modalities.

  13. GRIMD: distributed computing for chemists and biologists

    PubMed Central

    Piotto, Stefano; Biasi, Luigi Di; Concilio, Simona; Castiglione, Aniello; Cattaneo, Giuseppe

    2014-01-01

    Motivation: Biologists and chemists are facing problems of high computational complexity that require the use of several computers organized in clusters or in specialized grids. Examples of such problems can be found in molecular dynamics (MD), in silico screening, and genome analysis. Grid Computing and Cloud Computing are becoming prevalent mainly because of their competitive performance/cost ratio. Regrettably, the diffusion of Grid Computing is strongly limited because two main limitations: it is confined to scientists with strong Computer Science background and the analyses of the large amount of data produced can be cumbersome it. We have developed a package named GRIMD to provide an easy and flexible implementation of distributed computing for the Bioinformatics community. GRIMD is very easy to install and maintain, and it does not require any specific Computer Science skill. Moreover, permits preliminary analysis on the distributed machines to reduce the amount of data to transfer. GRIMD is very flexible because it shields the typical computational biologist from the need to write specific code for tasks such as molecular dynamics or docking calculations. Furthermore, it permits an efficient use of GPU cards whenever is possible. GRIMD calculations scale almost linearly and, therefore, permits to exploit efficiently each machine in the network. Here, we provide few examples of grid computing in computational biology (MD and docking) and bioinformatics (proteome analysis). Availability GRIMD is available for free for noncommercial research at www.yadamp.unisa.it/grimd Supplementary information www.yadamp.unisa.it/grimd/howto.aspx PMID:24516326

  14. [DNA computing].

    PubMed

    Błasiak, Janusz; Krasiński, Tadeusz; Popławski, Tomasz; Sakowski, Sebastian

    2011-01-01

    Biocomputers can be an alternative for traditional "silicon-based" computers, which continuous development may be limited due to further miniaturization (imposed by the Heisenberg Uncertainty Principle) and increasing the amount of information between the central processing unit and the main memory (von Neuman bottleneck). The idea of DNA computing came true for the first time in 1994, when Adleman solved the Hamiltonian Path Problem using short DNA oligomers and DNA ligase. In the early 2000s a series of biocomputer models was presented with a seminal work of Shapiro and his colleguas who presented molecular 2 state finite automaton, in which the restriction enzyme, FokI, constituted hardware and short DNA oligomers were software as well as input/output signals. DNA molecules provided also energy for this machine. DNA computing can be exploited in many applications, from study on the gene expression pattern to diagnosis and therapy of cancer. The idea of DNA computing is still in progress in research both in vitro and in vivo and at least promising results of these research allow to have a hope for a breakthrough in the computer science.

  15. Computational mechanics

    SciTech Connect

    Goudreau, G.L.

    1993-03-01

    The Computational Mechanics thrust area sponsors research into the underlying solid, structural and fluid mechanics and heat transfer necessary for the development of state-of-the-art general purpose computational software. The scale of computational capability spans office workstations, departmental computer servers, and Cray-class supercomputers. The DYNA, NIKE, and TOPAZ codes have achieved world fame through our broad collaborators program, in addition to their strong support of on-going Lawrence Livermore National Laboratory (LLNL) programs. Several technology transfer initiatives have been based on these established codes, teaming LLNL analysts and researchers with counterparts in industry, extending code capability to specific industrial interests of casting, metalforming, and automobile crash dynamics. The next-generation solid/structural mechanics code, ParaDyn, is targeted toward massively parallel computers, which will extend performance from gigaflop to teraflop power. Our work for FY-92 is described in the following eight articles: (1) Solution Strategies: New Approaches for Strongly Nonlinear Quasistatic Problems Using DYNA3D; (2) Enhanced Enforcement of Mechanical Contact: The Method of Augmented Lagrangians; (3) ParaDyn: New Generation Solid/Structural Mechanics Codes for Massively Parallel Processors; (4) Composite Damage Modeling; (5) HYDRA: A Parallel/Vector Flow Solver for Three-Dimensional, Transient, Incompressible Viscous How; (6) Development and Testing of the TRIM3D Radiation Heat Transfer Code; (7) A Methodology for Calculating the Seismic Response of Critical Structures; and (8) Reinforced Concrete Damage Modeling.

  16. The Effects of Integrating Service Learning into Computer Science: An Inter-Institutional Longitudinal Study

    ERIC Educational Resources Information Center

    Payton, Jamie; Barnes, Tiffany; Buch, Kim; Rorrer, Audrey; Zuo, Huifang

    2015-01-01

    This study is a follow-up to one published in computer science education in 2010 that reported preliminary results showing a positive impact of service learning on student attitudes associated with success and retention in computer science. That paper described how service learning was incorporated into a computer science course in the context of…

  17. The Effects of Integrating Service Learning into Computer Science: An Inter-Institutional Longitudinal Study

    ERIC Educational Resources Information Center

    Payton, Jamie; Barnes, Tiffany; Buch, Kim; Rorrer, Audrey; Zuo, Huifang

    2015-01-01

    This study is a follow-up to one published in computer science education in 2010 that reported preliminary results showing a positive impact of service learning on student attitudes associated with success and retention in computer science. That paper described how service learning was incorporated into a computer science course in the context of…

  18. [Preliminary identification of clinically significant Clostridium species].

    PubMed

    Balejová, Magda

    2010-06-01

    Preliminary identification of clinically significant Clostridium spp. is based on evaluating their microscopic and macroscopic morphology, Gram staining (Gram stain-positive structure of the bacterial wall), positive production of lecithinase, lipase and proteolytic activity on egg yolk agar, and simple chemical tests. If this preliminary identification is not sufficient, biochemical identification is performed, along with 16S-rRNA sequencing of the bacterial genome. The article comments on options of preliminary identification of clinically significant Clostridium spp.

  19. Preliminary considerations concerning actinide solubilities

    SciTech Connect

    Newton, T.W.; Bayhurst, B.P.; Daniels, W.R.; Erdal, B.R.; Ogard, A.E.

    1980-01-01

    Work at the Los Alamos Scientific Laboratory on the fundamental solution chemistry of the actinides has thus far been confined to preliminary considerations of the problems involved in developing an understanding of the precipitation and dissolution behavior of actinide compounds under environmental conditions. Attempts have been made to calculate solubility as a function of Eh and pH using the appropriate thermodynamic data; results have been presented in terms of contour maps showing lines of constant solubility as a function of Eh and pH. Possible methods of control of the redox potential of rock-groundwater systems by the use of Eh buffers (redox couples) is presented.

  20. Integral lift engine preliminary design

    NASA Technical Reports Server (NTRS)

    Pratt, W.; Leto, A.; Schaefer, R.

    1971-01-01

    A preliminary mechanical design of a complete lift fan engine system is reported. A description of the lift fan engine, layout drawings of the components and complete engine, and a discussion of the design analyses and results are presented. The design features and areas of analysis include fan and compressor rotor blades of composite construction, a combustor folded over the compressor, relatively high-temperature blades in the high-pressure turbine, the first stage of the low-pressure turbine used for bearing support and ducting of lubricant to the bearings, a complete lubrication system, critical speeds of the shafting, and vibration and flutter of the blading.

  1. Dielectric cure monitoring: Preliminary studies

    NASA Technical Reports Server (NTRS)

    Goldberg, B. E.; Semmel, M. L.

    1984-01-01

    Preliminary studies have been conducted on two types of dielectric cure monitoring systems employing both epoxy resins and phenolic composites. An Audrey System was used for 23 cure monitoring runs with very limited success. Nine complete cure monitoring runs have been investigated using a Micromet System. Two additional measurements were performed to investigate the Micromet's sensitivity to water absorption in a post-cure carbon-phenolic material. While further work is needed to determine data significance, the Micromet system appears to show promise as a feedback control device during processing.

  2. Preliminary ECLSS waste water model

    NASA Technical Reports Server (NTRS)

    Carter, Donald L.; Holder, Donald W., Jr.; Alexander, Kevin; Shaw, R. G.; Hayase, John K.

    1991-01-01

    A preliminary waste water model for input to the Space Station Freedom (SSF) Environmental Control and Life Support System (ECLSS) Water Processor (WP) has been generated for design purposes. Data have been compiled from various ECLSS tests and flight sample analyses. A discussion of the characterization of the waste streams comprising the model is presented, along with a discussion of the waste water model and the rationale for the inclusion of contaminants in their respective concentrations. The major objective is to establish a methodology for the development of a waste water model and to present the current state of that model.

  3. Preliminary ECLSS waste water model

    NASA Technical Reports Server (NTRS)

    Carter, Donald L.; Holder, Donald W., Jr.; Alexander, Kevin; Shaw, R. G.; Hayase, John K.

    1991-01-01

    A preliminary waste water model for input to the Space Station Freedom (SSF) Environmental Control and Life Support System (ECLSS) Water Processor (WP) has been generated for design purposes. Data have been compiled from various ECLSS tests and flight sample analyses. A discussion of the characterization of the waste streams comprising the model is presented, along with a discussion of the waste water model and the rationale for the inclusion of contaminants in their respective concentrations. The major objective is to establish a methodology for the development of a waste water model and to present the current state of that model.

  4. Quantum computers.

    PubMed

    Ladd, T D; Jelezko, F; Laflamme, R; Nakamura, Y; Monroe, C; O'Brien, J L

    2010-03-04

    Over the past several decades, quantum information science has emerged to seek answers to the question: can we gain some advantage by storing, transmitting and processing information encoded in systems that exhibit unique quantum properties? Today it is understood that the answer is yes, and many research groups around the world are working towards the highly ambitious technological goal of building a quantum computer, which would dramatically improve computational power for particular tasks. A number of physical systems, spanning much of modern physics, are being developed for quantum computation. However, it remains unclear which technology, if any, will ultimately prove successful. Here we describe the latest developments for each of the leading approaches and explain the major challenges for the future.

  5. Qubus computation

    NASA Astrophysics Data System (ADS)

    Munro, W. J.; Nemoto, Kae; Spiller, T. P.; van Loock, P.; Braunstein, Samuel L.; Milburn, G. J.

    2006-08-01

    Processing information quantum mechanically is known to enable new communication and computational scenarios that cannot be accessed with conventional information technology (IT). We present here a new approach to scalable quantum computing---a "qubus computer"---which realizes qubit measurement and quantum gates through interacting qubits with a quantum communication bus mode. The qubits could be "static" matter qubits or "flying" optical qubits, but the scheme we focus on here is particularly suited to matter qubits. Universal two-qubit quantum gates may be effected by schemes which involve measurement of the bus mode, or by schemes where the bus disentangles automatically and no measurement is needed. This approach enables a parity gate between qubits, mediated by a bus, enabling near-deterministic Bell state measurement and entangling gates. Our approach is therefore the basis for very efficient, scalable QIP, and provides a natural method for distributing such processing, combining it with quantum communication.

  6. Computational Psychiatry

    PubMed Central

    Wang, Xiao-Jing; Krystal, John H.

    2014-01-01

    Psychiatric disorders such as autism and schizophrenia arise from abnormalities in brain systems that underlie cognitive, emotional and social functions. The brain is enormously complex and its abundant feedback loops on multiple scales preclude intuitive explication of circuit functions. In close interplay with experiments, theory and computational modeling are essential for understanding how, precisely, neural circuits generate flexible behaviors and their impairments give rise to psychiatric symptoms. This Perspective highlights recent progress in applying computational neuroscience to the study of mental disorders. We outline basic approaches, including identification of core deficits that cut across disease categories, biologically-realistic modeling bridging cellular and synaptic mechanisms with behavior, model-aided diagnosis. The need for new research strategies in psychiatry is urgent. Computational psychiatry potentially provides powerful tools for elucidating pathophysiology that may inform both diagnosis and treatment. To achieve this promise will require investment in cross-disciplinary training and research in this nascent field. PMID:25442941

  7. Payload/orbiter contamination control requirement study: Computer interface

    NASA Technical Reports Server (NTRS)

    Bareiss, L. E.; Hooper, V. W.; Ress, E. B.; Strange, D. A.

    1976-01-01

    A preliminary assessment of the computer interface requirements of the Spacelab configuration contamination computer model was conducted to determine the compatibility of the program, as presently formatted, with the computer facilities at MSFC. The necessary Spacelab model modifications are pointed out. The MSFC computer facilities and their future plans are described, and characteristics of the various computers as to availability and suitability for processing the contamination program are discussed. A listing of the CDC 6000 series and UNIVAC 1108 characteristics is presented so that programming requirements can be compared directly and differences noted.

  8. Computational mechanics

    SciTech Connect

    Raboin, P J

    1998-01-01

    The Computational Mechanics thrust area is a vital and growing facet of the Mechanical Engineering Department at Lawrence Livermore National Laboratory (LLNL). This work supports the development of computational analysis tools in the areas of structural mechanics and heat transfer. Over 75 analysts depend on thrust area-supported software running on a variety of computing platforms to meet the demands of LLNL programs. Interactions with the Department of Defense (DOD) High Performance Computing and Modernization Program and the Defense Special Weapons Agency are of special importance as they support our ParaDyn project in its development of new parallel capabilities for DYNA3D. Working with DOD customers has been invaluable to driving this technology in directions mutually beneficial to the Department of Energy. Other projects associated with the Computational Mechanics thrust area include work with the Partnership for a New Generation Vehicle (PNGV) for ''Springback Predictability'' and with the Federal Aviation Administration (FAA) for the ''Development of Methodologies for Evaluating Containment and Mitigation of Uncontained Engine Debris.'' In this report for FY-97, there are five articles detailing three code development activities and two projects that synthesized new code capabilities with new analytic research in damage/failure and biomechanics. The article this year are: (1) Energy- and Momentum-Conserving Rigid-Body Contact for NIKE3D and DYNA3D; (2) Computational Modeling of Prosthetics: A New Approach to Implant Design; (3) Characterization of Laser-Induced Mechanical Failure Damage of Optical Components; (4) Parallel Algorithm Research for Solid Mechanics Applications Using Finite Element Analysis; and (5) An Accurate One-Step Elasto-Plasticity Algorithm for Shell Elements in DYNA3D.

  9. LHC Computing

    ScienceCinema

    Lincoln, Don

    2016-07-12

    The LHC is the world’s highest energy particle accelerator and scientists use it to record an unprecedented amount of data. This data is recorded in electronic format and it requires an enormous computational infrastructure to convert the raw data into conclusions about the fundamental rules that govern matter. In this video, Fermilab’s Dr. Don Lincoln gives us a sense of just how much data is involved and the incredible computer resources that makes it all possible.

  10. Computational vision

    NASA Technical Reports Server (NTRS)

    Barrow, H. G.; Tenenbaum, J. M.

    1981-01-01

    The range of fundamental computational principles underlying human vision that equally apply to artificial and natural systems is surveyed. There emerges from research a view of the structuring of vision systems as a sequence of levels of representation, with the initial levels being primarily iconic (edges, regions, gradients) and the highest symbolic (surfaces, objects, scenes). Intermediate levels are constrained by information made available by preceding levels and information required by subsequent levels. In particular, it appears that physical and three-dimensional surface characteristics provide a critical transition from iconic to symbolic representations. A plausible vision system design incorporating these principles is outlined, and its key computational processes are elaborated.

  11. Computer systems

    NASA Technical Reports Server (NTRS)

    Olsen, Lola

    1992-01-01

    In addition to the discussions, Ocean Climate Data Workshop hosts gave participants an opportunity to hear about, see, and test for themselves some of the latest computer tools now available for those studying climate change and the oceans. Six speakers described computer systems and their functions. The introductory talks were followed by demonstrations to small groups of participants and some opportunities for participants to get hands-on experience. After this familiarization period, attendees were invited to return during the course of the Workshop and have one-on-one discussions and further hands-on experience with these systems. Brief summaries or abstracts of introductory presentations are addressed.

  12. Computer viruses

    NASA Technical Reports Server (NTRS)

    Denning, Peter J.

    1988-01-01

    The worm, Trojan horse, bacterium, and virus are destructive programs that attack information stored in a computer's memory. Virus programs, which propagate by incorporating copies of themselves into other programs, are a growing menace in the late-1980s world of unprotected, networked workstations and personal computers. Limited immunity is offered by memory protection hardware, digitally authenticated object programs,and antibody programs that kill specific viruses. Additional immunity can be gained from the practice of digital hygiene, primarily the refusal to use software from untrusted sources. Full immunity requires attention in a social dimension, the accountability of programmers.

  13. Descent advisor preliminary field test

    NASA Technical Reports Server (NTRS)

    Green, Steven M.; Vivona, Robert A.; Sanford, Beverly

    1995-01-01

    A field test of the Descent Advisor (DA) automation tool was conducted at the Denver Air Route Traffic Control Center in September 1994. DA is being developed to assist Center controllers in the efficient management and control of arrival traffic. DA generates advisories, based on trajectory predictions, to achieve accurate meter-fix arrival times in a fuel efficient manner while assisting the controller with the prediction and resolution of potential conflicts. The test objectives were to evaluate the accuracy of DA trajectory predictions for conventional- and flight-management-system-equipped jet transports, to identify significant sources of trajectory prediction error, and to investigate procedural and training issues (both air and ground) associated with DA operations. Various commercial aircraft (97 flights total) and a Boeing 737-100 research aircraft participated in the test. Preliminary results from the primary test set of 24 commercial flights indicate a mean DA arrival time prediction error of 2.4 sec late with a standard deviation of 13.1 sec. This paper describes the field test and presents preliminary results for the commercial flights.

  14. Preliminary Investigation of a Paraglider

    NASA Technical Reports Server (NTRS)

    Rogallo, Francis M.; Lowry, John G.; Croom, Delwin R.; Taylor, Robert T.

    1960-01-01

    A preliminary investigation of the aerodynamic and control characteristics of a flexible glider similar to a parachute in construction has been made at the Langley Research Center to evaluate its capabilities as a reentry glider. Preliminary weight estimates of the proposed vehicle indicate that such a structure can be made with extremely low wing loading. Maximum temperatures during the reentry maneuver might be held as low as about 1,500 F. The results of wind-tunnel and free-glide tests show that the glider when constructed of nonporous material performed extremely well at subsonic speeds and could be flown at angles of attack from about 200 to 900. At supersonic speeds the wing showed none of the unfavorable tendencies exhibited by conventional parachutes at these speeds, such as squidding and breathing. Several methods of packing and deploying the glider have been successfully demonstrated. The results of this study indicate that this flexible-lifting-surface concept may provide a lightweight controllable paraglider for manned space vehicles.

  15. Topaz II preliminary safety assessment

    NASA Astrophysics Data System (ADS)

    Marshall, Albert C.; Standley, Vaughn; Voss, Susan S.; Haskin, Eric

    1993-01-01

    The Strategic Defense Initiative Organization (SDIO) decided to investigate the possibility of launching a Russian Topaz II space nuclear power system. A preliminary safety assessment was conducted to determine whether or not a space mission could be conducted safely and within budget constraints. As part of this assessment, a safety policy and safety functional requirements were developed to guide both the safety assessment and future Topaz II activities. A review of the Russian flight safety program was conducted and documented. Our preliminary safety assessment included a top level event tree, neutronic analysis of normal and accident configurations, an evaluation of temperature coefficients of reactivity, a reentry and disposal analysis, and analysis of postulated launch abort impact accidents, and an analysis of postulated propellant fire and explosion accidents. Based on the assessment, it appears that it will be possible to safely launch the Topaz II system in the U.S. with some possible system modifications. The principal system modifications will probably include design changes to preclude water flooded criticality and to assure intact reentry.

  16. Descent Advisor Preliminary Field Test

    NASA Technical Reports Server (NTRS)

    Green, Steven M.; Vivona, Robert A.; Sanford, Beverly

    1995-01-01

    A field test of the Descent Advisor (DA) automation tool was conducted at the Denver Air Route Traffic Control Center in September 1994. DA is being developed to assist Center controllers in the efficient management and control of arrival traffic. DA generates advisories, based on trajectory predictions, to achieve accurate meter-fix arrival times in a fuel efficient manner while assisting the controller with the prediction and resolution of potential conflicts. The test objectives were: (1) to evaluate the accuracy of DA trajectory predictions for conventional and flight-management system equipped jet transports, (2) to identify significant sources of trajectory prediction error, and (3) to investigate procedural and training issues (both air and ground) associated with DA operations. Various commercial aircraft (97 flights total) and a Boeing 737-100 research aircraft participated in the test. Preliminary results from the primary test set of 24 commercial flights indicate a mean DA arrival time prediction error of 2.4 seconds late with a standard deviation of 13.1 seconds. This paper describes the field test and presents preliminary results for the commercial flights.

  17. Topaz II preliminary safety assessment

    SciTech Connect

    Marshall, A.C. ); Standley, V. ); Voss, S.S. ); Haskin, E. . Dept. of Chemical and Nuclear Engineering)

    1992-01-01

    The Strategic Defense Initiative Organization (SDIO) decided to investigate the possibility of launching a Russian Topaz 11 space nuclear power system. A preliminary safety assessment was conducted to determine whether or not a space mission could be conducted safely and within budget constraints. As part of this assessment, a safety policy and safety functional requirements were developed to guide both the safely assessment and future Topaz II activities. A review of the Russian flight safety program was conducted and documented. Our preliminary safety assessment included a top level event tree, neutronic analysis of normal and accident configurations, an evaluation of temperature coefficients of reactivity, a reentry and disposal analysis, and analysis of postulated launch abort impact accidents, and an analysis of postulated propellant fire and explosion accidents. Based on the assessment, it appears that it will be possible to safely launch the Topaz II system in the US with some possible system modifications. The principal system modifications will probably include design changes to preclude water flooded criticality and to assure intact reentry.

  18. Topaz II preliminary safety assessment

    SciTech Connect

    Marshall, A.C. ); Standley, V. ); Voss, S.S. ); Haskin, E. )

    1993-01-10

    The Strategic Defense Initiative Organization (SDIO) decided to investigate the possibility of launching a Russian Topaz II space nuclear power system. A preliminary safety assessment was conducted to determine whether or not a space mission could be conducted safely and within budget constraints. As part of this assessment, a safety policy and safety functional requirements were developed to guide both the safety assessment and future Topaz II activities. A review of the Russian flight safety program was conducted and documented. Our preliminary safety assessment included a top level event tree, neutronic analysis of normal and accident configurations, an evaluation of temperature coefficients of reactivity, a reentry and disposal analysis, and analysis of postulated launch abort impact accidents, and an analysis of postulated propellant fire and explosion accidents. Based on the assessment, it appears that it will be possible to safely launch the Topaz II system in the U.S. with some possible system modifications. The principal system modifications will probably include design changes to preclude water flooded criticality and to assure intact reentry.

  19. Computational Physics.

    ERIC Educational Resources Information Center

    Borcherds, P. H.

    1986-01-01

    Describes an optional course in "computational physics" offered at the University of Birmingham. Includes an introduction to numerical methods and presents exercises involving fast-Fourier transforms, non-linear least-squares, Monte Carlo methods, and the three-body problem. Recommends adding laboratory work into the course in the…

  20. Computer Corner.

    ERIC Educational Resources Information Center

    Smith, David A.; And Others

    1986-01-01

    APL was invented specifically as a mathematical teaching tool, and is an excellent vehicle for teaching mathematical concepts using computers. This article illustrates the use of APL in teaching many different topics in mathematics, including logic, set theory, functions, statistics, linear algebra, and matrices. (MNS)