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Institution

General Electric

CompanyBoston, Massachusetts, United States
About: General Electric is a company organization based out in Boston, Massachusetts, United States. It is known for research contribution in the topics: Turbine & Rotor (electric). The organization has 76365 authors who have published 110557 publications receiving 1885108 citations. The organization is also known as: General Electric Company & GE.
Topics: Turbine, Rotor (electric), Signal, Combustor, Coating


Papers
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Journal ArticleDOI
TL;DR: 4D PET/CT is clinically a feasible method, to correct for respiratory motion artifacts in PET/ CT imaging of the thorax, and can reduce smearing, improve the accuracy in PET-CT co-registration, and increase the measured SUV.
Abstract: We have reported in our previous studies on the methodology, and feasibility of 4D-PET (Gated PET) acquisition, to reduce respiratory motion artifact in PET imaging of the thorax. In this study, we expand our investigation to address the problem of respiration motion in PET/CT imaging. The respiratory motion of four lung cancer patients were monitored by tracking external markers placed on the thorax. A 4D-CT acquisition was performed using a "step-and-shoot" technique, in which computed tomography (CT) projection data were acquired over a complete respiratory cycle at each couch position. The period of each CT acquisition segment was time stamped with an "x-ray ON" signal, which was recorded by the tracking system. 4D-CT data were then sorted into 10 groups, according to their corresponding phase of the breathing cycle. 4D-PET data were acquired in the gated mode, where each breathing cycle was divided into ten 0.5 s bins. For both CT and PET acquisitions, patients received audio prompting to regularize breathing. The 4D-CT and 4D-PET data were then correlated according to respiratory phase. The effect of 4D acquisition on improving the co-registration of PET and CT images, reducing motion smearing, and consequently increase the quantitation of the SUV, were investigated. Also, quantitation of the tumor motions in PET, and CT, were studied and compared. 4D-PET with matching phase 4D-CTAC showed an improved accuracy in PET-CT image co-registration of up to 41%, compared to measurements from 4D-PET with clinical-CTAC. Gating PET data in correlation with respiratory motion reduced motion-induced smearing, thereby decreasing the observed tumor volume, by as much as 43%. 4D-PET lesions volumes showed a maximum deviation of 19% between clinical CT and phase- matched 4D-CT attenuation corrected PET images. In CT, 4D acquisition resulted in increasing the tumor volume in two patients by up to 79%, and decreasing it in the other two by up to 35%. Consequently, these corrections have yielded an increase in the measured SUV by up to 16% over the clinical measured SUV, and 36% over SUV's measured in 4D-PET with clinical-CT Attenuation Correction (CTAC) SUV's. Quantitation of the maximum tumor motion amplitude, using 4D-PET and 4D-CT, showed up to 30% discrepancy between the two modalities. We have shown that 4D PET/CT is clinically a feasible method, to correct for respiratory motion artifacts in PET/CT imaging of the thorax. 4D PET/CT acquisition can reduce smearing, improve the accuracy in PET-CT co-registration, and increase the measured SUV. This should result in an improved tumor assessment for patients with lung malignancies.

359 citations

Journal ArticleDOI
TL;DR: Plasma tau partly reflects AD pathology, but the overlap between normal aging and AD is large, especially in patients without dementia, and results do not support plasma tau as an AD biomarker in individual people.
Abstract: Objective: To test whether plasma tau is altered in Alzheimer disease (AD) and whether it is related to changes in cognition, CSF biomarkers of AD pathology (including β-amyloid [Aβ] and tau), brain atrophy, and brain metabolism. Methods: This was a study of plasma tau in prospectively followed patients with AD (n = 179), patients with mild cognitive impairment (n = 195), and cognitive healthy controls (n = 189) from the Alzheimer9s Disease Neuroimaging Initiative (ADNI) and cross-sectionally studied patients with AD (n = 61), mild cognitive impairment (n = 212), and subjective cognitive decline (n = 174) and controls (n = 274) from the Biomarkers for Identifying Neurodegenerative Disorders Early and Reliably (BioFINDER) study at Lund University, Sweden. A total of 1284 participants were studied. Associations were tested between plasma tau and diagnosis, CSF biomarkers, MRI measures, 18 fluorodeoxyglucose-PET, and cognition. Results: Higher plasma tau was associated with AD dementia, higher CSF tau, and lower CSF Aβ 42 , but the correlations were weak and differed between ADNI and BioFINDER. Longitudinal analysis in ADNI showed significant associations between plasma tau and worse cognition, more atrophy, and more hypometabolism during follow-up. Conclusions: Plasma tau partly reflects AD pathology, but the overlap between normal aging and AD is large, especially in patients without dementia. Despite group-level differences, these results do not support plasma tau as an AD biomarker in individual people. Future studies may test longitudinal plasma tau measurements in AD.

359 citations

Journal ArticleDOI
08 May 1987-Science
TL;DR: The polychlorinated biphenyl (PCB) residues in the aquatic sediments from six PCB spill sites showed changes in PCB isomer and homolog (congener) distribution that indicated the occurrence of reductive dechlorination.
Abstract: The polychlorinated biphenyl (PCB) residues in the aquatic sediments from six PCB spill sites showed changes in PCB isomer and homolog (congener) distribution that indicated the occurrence of reductive dechlorination. The PCB dechlorinations exhibited several distinct congener selection patterns that indicated mediation by several different localized populations of anaerobic microorganisms. The higher (more heavily chlorinated) PCB congeners that were preferentially attacked by the observed dechlorination processes included all those that are either pharmacologically active or persistent in higher animals. All the lower (less heavily chlorinated) PCB congeners formed by the dechlorinations were species that are known to be oxidatively biodegradable by the bacteria of aerobic environments.

358 citations

Journal ArticleDOI
Novak Zuber1
TL;DR: In this article, it is shown that the same equations which predict the heat-transfer coefficient and the average turbulent velocity fluctuation in natural turbulent convection from a horizontal surface can be used in the regime of isolated bubbles if the vapor void coefficient i.e. the vapor hold-up is taken into account in evaluating the mean density of the fluid.

357 citations

Journal ArticleDOI
TL;DR: In this paper, a large-eddy simulation of turbulent premixed reacting flows in a gas turbine combustor (General Electric's lean premixed dry low-NOx LM6000) has been carried out to evaluate the potential of LES for design studies of realistic hardware.
Abstract: Large-eddy simulation (LES) of turbulent premixed reacting flows in a gas turbine combustor (General Electric's lean premixed dry low-NOx LM6000) has been carried out to evaluate the potential of LES for design studies of realistic hardware. A flamelet model for the premixed flame is combined with a dynamic model for the subgrid kinetic energy to simulate the propagation of the turbulent flame in this high swirl and high Reynolds number flow. Comparison of the computed results with experimental data indicate good agreement in spite of relatively coarse grid resolution employed in the LES. These results provide significant confidence that LES capability for design studies of practical interest is feasible in the near future.

357 citations


Authors

Showing all 76370 results

NameH-indexPapersCitations
Cornelia M. van Duijn1831030146009
Krzysztof Matyjaszewski1691431128585
Gary H. Glover12948677009
Mark E. Thompson12852777399
Ron Kikinis12668463398
James E. Rothman12535860655
Bo Wang119290584863
Wei Lu111197361911
Harold J. Vinegar10837930430
Peng Wang108167254529
Hans-Joachim Freund10696246693
Carl R. Woese10527256448
William J. Koros10455038676
Thomas A. Lipo10368243110
Gene H. Golub10034257361
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Performance
Metrics
No. of papers from the Institution in previous years
YearPapers
20231
202216
2021415
20201,027
20191,418
20181,862