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10. Radiative Forcing by Well-Mixed Greenhouse Gases: Estimates from Climate Models in the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report (AR4)

Author

Collins, W. D, Ramaswamy, V, Schwarzkopf, M. D, Sun, Y, Portmann, R. W, Fu, Q, Casanova, S. E. B, Dufresne, J.-L, Fillmore, D. W, Forster, P. M. D, Galin, V. Y, Gohar, L. K, Ingram, W. J, Kratz, D. P, Lefebvre, M.-P, Li, J, Marquet, P, Oinas, V, Tsushima, Y, Uchiyama, T, and Zhong, W. Y

Subjects
Earth Resources And Remote Sensing
Abstract

The radiative effects from increased concentrations of well-mixed greenhouse gases (WMGHGs) represent the most significant and best understood anthropogenic forcing of the climate system. The most comprehensive tools for simulating past and future climates influenced by WMGHGs are fully coupled atmosphere-ocean general circulation models (AOGCMs). Because of the importance of WMGHGs as forcing agents it is essential that AOGCMs compute the radiative forcing by these gases as accurately as possible. We present the results of a radiative transfer model intercomparison between the forcings computed by the radiative parameterizations of AOGCMs and by benchmark line-by-line (LBL) codes. The comparison is focused on forcing by CO2, CH4, N2O, CFC-11, CFC-12, and the increased H2O expected in warmer climates. The models included in the intercomparison include several LBL codes and most of the global models submitted to the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report (AR4). In general, the LBL models are in excellent agreement with each other. However, in many cases, there are substantial discrepancies among the AOGCMs and between the AOGCMs and LBL codes. In some cases this is because the AOGCMs neglect particular absorbers, in particular the near-infrared effects of CH4 and N2O, while in others it is due to the methods for modeling the radiative processes. The biases in the AOGCM forcings are generally largest at the surface level. We quantify these differences and discuss the implications for interpreting variations in forcing and response across the multimodel ensemble of AOGCM simulations assembled for the IPCC AR4.

Published
2006
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13. Radiative Forcing by Contrails

Author

Meerkoetter, R, Schumann, U, Doelling, D. R, Nakajima, T, and Tsushima, Y

Subjects
Meteorology And Climatology
Abstract

A parametric study of the instantaneous radiative impact of contrails is presented using three different radiative transfer models for a series of model atmospheres and cloud parameters. Contrails are treated as geometrically and optically thin plane parallel homogeneous cirrus layers in a static atmospheres The ice water content is varied as a function of ambient temperature. The model atmospheres include tropical, mid-latitude, and subarctic summer and winter atmospheres Optically thin contrails cause a positive net forcing at top of the atmosphere. At the surface the radiative forcing is negative during daytime. The forcing increases with the optical depth and the amount of contrail cover. At the top of the atmosphere a mean contrail cover of 0.1% with average optical depth of 0.2 to 0.5 causes about 0.01 to 0.03 W/m(exp 2)a daily mean instantaneous radiative forcing. Contrails cool the surface during the day and heat the surface during the night, and hence reduce the daily temperature amplitude The net effect depends strongly on the daily variation of contrail cloud cover. The indirect radiative forcing due to particle changes in natural cirrus clouds may be of the same magnitude as the direct one due to additional cover.

Published
1999

16. Supplementary Material for: 18F-FAMT PET Is Useful to Distinguish between Specific Uptake and Nonspecific Uptake Compared to 18F-Flourodeoxyglucose Position Emission Tomography in Esophageal Cancer Patients

Author

Sohda, M., Miyazaki, T., Honjyo, H., Hara, K., Ozawa, D., Sakai, M., Yokobori, T., Higuchi, T., Tsushima, Y., and Kuwano, H.

Abstract

Background: L-[3-18F]-α-methyltyrosine (18F-FAMT) solely accumulates in tumor cells via an amino acid transport system. This selective uptake pattern results in a very high tumor-to-background ratio, enabling clear delineation of the tumor. The purpose of the present study was to assess the significance of 18F-FAMT PET, which shows little nonspecific uptake compared to 18F-flourodeoxyglucose position emission tomography (FDG PET) in esophageal cancer patients. Methodology: PET-CT studies with 18F-FAMT and 18F-FDG were performed as part of pretreatment work-up in 82 patients with histologically confirmed esophageal cancer. We evaluated nonspecific uptakes of 18F-FDG and 18F-FAMT PET. Results: The nonspecific uptake of 18F-FAMT PET was lower than that of 18F-FDG PET (p = 0.282). In the operation group, 26.1% demonstrated nonspecific uptake in 18F-FDG PET, whereas only 2.38% (1 case) demonstrated nonspecific uptake in 18F-FAMT PET (p = 0.433). In the inoperable group, 47.5% showed nonspecific uptake in 18F-FDG PET, whereas 5.0% showed nonspecific uptake in 18F-FAMT PET (p = 0.079). Conclusion: A crucial point for the diagnostic value of PET is distinguishing specific and nonspecific uptake. 18F-FAMT-PET is a very superior modality with regard to the lower rate of nonspecific uptake in esophageal cancer.

Published
2017
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17. Axillary lymph-node metabolic activity assessment on 18F-FDG-PET/CT in rheumatoid arthritis patients treated with biologic therapies.

Author

Dam, TT, Okamura, K, Nakajima, T, Yonemoto, Y, Suto, T, Arisaka, Y, Tomonaga, H, Tachibana, M, Tajika, T, Vu, LD, Chikuda, H, Tsushima, Y, Dam, T T, and Vu, L D

Subjects
WRIST, GLUCOSE metabolism, POSITRON emission tomography computed tomography, BIOMARKERS, ARM, AXILLA, CELL receptors, LYMPH nodes, TUMOR necrosis factors, RADIOPHARMACEUTICALS, RHEUMATOID arthritis, DEOXY sugars, CHEMICAL inhibitors
Abstract

Objective: Recent studies have provided new insights into the role of lymph nodes (LNs) in rheumatoid arthritis (RA). The aim of this study was to evaluate the metabolic activity of the axillary LNs in relation to that of the upper limb joints and the clinical assessment of disease activity in RA patients treated with biologic therapies.Method: 18F-fluorodeoxyglucose-positron emission tomography/computed tomography (18F-FDG-PET/CT) scans were acquired for 64 patients with RA at baseline and after 6 months of biologic therapy, and the patients' clinical status was evaluated. The maximum standardized uptake value (SUVmax), metabolic active volume, and total lesion glycolysis (TLG) were used to assess glucose metabolism in the LNs and 12 joints. Clinical evaluations included serum markers and the Disease Activity Score based on 28-joint count-erythrocyte sedimentation rate (DAS28-ESR).Results: Changes in the SUVmax and TLG for the axillary LNs correlated significantly with those of the ipsilateral wrist joints. There was a positive correlation between the changes in the three metabolic parameters of the axillary LNs and the changes in disease activity after treatment. After 6 months of biologic therapy, all metabolic parameters for the axillary LNs in patients with a DAS28-ESR < 3.2 were significantly lower than those of patients with a DAS28-ESR ≥ 3.2.Conclusion: A relationship between the glucose metabolism of the axillary LNs and the ipsilateral wrist joints was demonstrated by the 18F-FDG-PET/CT parameters. The metabolic activity and active volume of axillary LNs may reflect the therapeutic response to the biologic treatment of RA. [ABSTRACT FROM AUTHOR]

Published
2020
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19. Differences in the distribution of cerebral microbleeds in multiple eastern and western populations (dicom): Global individual participant data meta-analysis

Author

Yakushiji, Y., primary, Wilson, D., additional, Ambler, G., additional, Charidimou, A., additional, Hara, H., additional, Imaizumi, T., additional, Kohara, K., additional, Kwon, H.M., additional, Launer, L.J., additional, Mok, V., additional, Romero, J.R., additional, Srikanth, V., additional, Takashima, Y., additional, Tsushima, Y., additional, Wolf, P.A., additional, Yamaguchi, S., additional, and Werring, D.J., additional

Published
2017
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30. Biological significance of fluorine-18-α-methyltyrosine (FAMT) uptake on PET in patients with oesophageal cancer

Author

Suzuki, S, primary, Kaira, K, additional, Ohshima, Y, additional, Ishioka, N S, additional, Sohda, M, additional, Yokobori, T, additional, Miyazaki, T, additional, Oriuchi, N, additional, Tominaga, H, additional, Kanai, Y, additional, Tsukamoto, N, additional, Asao, T, additional, Tsushima, Y, additional, Higuchi, T, additional, Oyama, T, additional, and Kuwano, H, additional

Published
2014
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