Publications by authors named "T P Seĭ"

We propose a linear separation method of multivariate quantitative data in such a way that the average of each variable in the positive group is larger than that of the negative group. Here, the coefficients of the separating hyperplane are restricted to be positive. Our method is derived from the maximum entropy principle.

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In conventional hydrothermal synthesis of porous titanosilicate materials, undesired aggregation of TiO species during the synthesis limits the content of active four-coordinated Ti to an Si/Ti ratio of about 40. Aiming to increase the content of active four-coordinated Ti species, we report a bottom-up synthesis of titanosilicate nanoparticles using a Ti-incorporated cubic silsesquioxane cage as a precursor, which allowed incorporating a larger number of four-coordinated Ti species in the silica matrix to reach an Si/Ti ratio of 19. Even at this relatively high Ti concentration, the catalytic activity in the epoxidation of cyclohexene over the titanosilicate nanoparticles was comparable to that of a conventional reference Ti catalyst, Ti-MCM-41, with an Si/Ti ratio of 60.

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To determine the effectiveness of living-donor lobar lung transplantation (LDLLT), it is necessary to predict the recipient's postoperative lung function. Traditionally, Date's formula, also called the segmental ratio, has used the number of lung segments to estimate the forced vital capacity (FVC) of grafts in LDLLT. To provide a more precise estimate of graft FVC, we calculated the volumes of the lower lobe and total lung using three-dimensional computed tomography (3D-CT) and the volume ratio between them.

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In recent years, magnetic resonance imaging (MRI) with diffusion-weighted imaging (DWI) has seen wide clinical use, such as for early detection of cerebrovascular diseases and whole body screening for tumors. The apparent diffusion coefficient (ADC) standard phantom, which mimics the ADC values of several lesions in the body, is indispensable for the development of new pulse sequences for DWI, such as diffusion-weighted whole-body imaging with background body-signal suppression (DWIBS). However, information on the ADC values of the previously reported ADC standard phantoms is limited, because these phantoms were made using only a few different materials at a limited range of concentrations, and the ADC values were measured only at certain temperatures.

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Diffusion-weighted magnetic resonance imaging (MRI) is frequently used clinically, and is available for the whole-body screening for tumors. The exact mechanism by which the apparent diffusion coefficient (ADC) value decreases in tumorous tissue remains unclear, although various theories have been proposed, including intracellular and extracellular factor theories. It is impossible to distinguish each factor in the intracellular and extracellular spaces as the source of MR signal generation by means of conventional comparison between MR images and pathological specimens.

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