scholarly journals Molecule Diffusion Behavior of Tritium and Selenium in Mongolia Clay Rock by Numerical Analysis of the Spatial and Temporal Variation

Minerals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 875
Author(s):  
Chuan-Pin Lee ◽  
Yanqin Hu ◽  
Neng-Chuan Tien ◽  
Shih-Chin Tsai ◽  
Yunfeng Shi ◽  
...  
Keyword(s):  
Numerical Analysis ◽  
Temporal Variation ◽  
Diffusion Coefficients ◽  
Disposal Site ◽  
Spatial And Temporal Variation ◽  
Sorption Behavior ◽  
Clay Rock ◽  
Diffusion Behavior ◽  
Apparent Diffusion Coefficients ◽  
Apparent Diffusion

Clay rock in the Tamusu (TMS) area in the Inner Mongolia province is one candidate as a geological disposal site for highly radioactive waste in China. The diffusion behavior of HTO and Se(IV) in Tamusu clay rock was studied by through-diffusion (TD) experiments and numerical analysis to determine the spatial and temporal variation. A minimum error analysis was conducted to determine the HTO and Se(IV) diffusion coefficients in compacted TMS clay. The TD experimental results and numerical analysis showed that the diffusion of HTO and Se reached a steady state within 7 and 50 days, respectively, and the apparent diffusion coefficients (Da) decreased with the increases in the compacted density. In fact, there was retardation of Se diffusion in intact TMS clay rock. A two-site sorption model for Se was applied to simulate fast and slow sorption behavior quantitatively.

scholarly journals Heterogeneity of Apparent Diffusion Coefficients Within Infarcts

Stroke ◽  
2001 ◽  
Vol 32 (7) ◽  
pp. 1695-1696
Author(s):  
Pratik Mukherjee ◽  
Robert C. McKinstry ◽  
Joshua S. Shimony ◽  
Erbil Akbudak ◽  
Abraham Z. Snyder ◽  
...  
Keyword(s):  
Diffusion Coefficients ◽  
Apparent Diffusion Coefficients ◽  
Apparent Diffusion

Minimum apparent diffusion coefficients in the evaluation of brain tumors

2005 ◽  
Vol 55 (3) ◽  
pp. 393-400 ◽  
Author(s):  
Omer Kitis ◽  
Hakan Altay ◽  
Cem Calli ◽  
Nilgun Yunten ◽  
Taner Akalin ◽  
...  
Keyword(s):  
Brain Tumors ◽  
Diffusion Coefficients ◽  
Apparent Diffusion Coefficients ◽  
Apparent Diffusion

scholarly journals Hypoxia-Induced Acute Mountain Sickness is Associated with Intracellular Cerebral Edema: A 3 T Magnetic Resonance Imaging Study

2007 ◽  
Vol 28 (1) ◽  
pp. 198-206 ◽  
Author(s):  
Guus G Schoonman ◽  
Peter S Sándor ◽  
Arto C Nirkko ◽  
Thomas Lange ◽  
Thomas Jaermann ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Cerebral Edema ◽  
Diffusion Coefficients ◽  
Visual Inspection ◽  
Acute Mountain Sickness ◽  
Cerebral White Matter ◽  
Resonance Imaging ◽  
Apparent Diffusion Coefficients ◽  
Apparent Diffusion ◽  
Mountain Sickness

Acute mountain sickness is common among not acclimatized persons ascending to high altitude; the underlying mechanism is unknown, but may be related to cerebral edema. Nine healthy male students were studied before and after 6-h exposure to isobaric hypoxia. Subjects inhaled room air enriched with N2 to obtain arterial O2 saturation values of 75 to 80%. Acute mountain sickness was assessed with the environmental symptom questionnaire, and cerebral edema with 3 T magnetic resonance imaging in 18 regions of interest in the cerebral white matter. The main outcome measures were development of intra- and extracellular cerebral white matter edema assessed by visual inspection and quantitative analysis of apparent diffusion coefficients derived from diffusion-weighted imaging, and B0 signal intensities derived from T2-weighted imaging. Seven of nine subjects developed acute mountain sickness. Mean apparent diffusion coefficient increased 2.12% (baseline, 0.80±0.09; 6 h hypoxia, 0.81 ± 0.09; P = 0.034), and mean B0 signal intensity increased 4.56% (baseline, 432.1 ±98.2; 6 h hypoxia, 450.7 ± 102.5; P < 0.001). Visual inspection of magnetic resonance images failed to reveal cerebral edema. Cerebral acute mountain sickness scores showed a negative correlation with relative changes of apparent diffusion coefficients ( r = 0.83, P = 0.006); there was no correlation with relative changes of B0 signal intensities. In conclusion, isobaric hypoxia is associated with mild extracellular (vasogenic) cerebral edema irrespective of the presence of acute mountain sickness in most subjects, and severe acute mountain sickness with additional mild intracellular (cytotoxic) cerebral edema.

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