248 research outputs found
"Computed tomographic evaluation of novel custom-made artificial bones, ""CT-bone"", applied for maxillofacial reconstruction."
埼玉医科大学平成28年
Cold Air Mass Analysis of the Record-Breaking Cold Surge Event over East Asia in January 2016
An extreme cold surge event caused record-breaking low temperatures in East Asia during 20-25 January 2016. The planetary- and synoptic-scale feature of the event is investigated quantitatively using the isentropic cold air mass analysis with a threshold potential temperature of 280 K. Because cold air mass is an adiabatically conservative quantity, it is suitable for tracing and examining the extreme cold surges. We further introduced a metric named mean wind of cold air mass, which divides the factor of cold air mass evolution into convergence and advection parts. The new metric allowed us to trace the evolution of the cold air mass with dynamic consistency for a period of more than a week. A thick cold air mass built up over southern Sakha by a convergent cold air mass flow during 16-18 January. It migrated westward and reached Lake Baikal. On 20 January, an intense Siberian High developed, with an eastward-moving mid-upper-level ridge, producing a strong surface pressure gradient over the coastal regions of the Asian continent. This ridge and a cutoff low to the adjacent east formed a northerly flow in the mid-upper troposphere. The resultant southward flow through the troposphere blew the cold air mass over 480 hPa in thickness to the subtropical region of East Asia, causing strong cold surges there on 24 and 25 January. The abnormality of the event is further quantified using extreme value theory. The cold air mass gradually became rare along the path of the cold air mass from Lake Baikal to eastern China, which experienced as thick a cold air mass as once in 200 years. The cold air mass itself shows little change in thickness. Therefore, the migration of a cold air mass over 540 hPa in thickness from northern Siberia is the major cause of this cold surge extreme
Quantum channel decomposition with pre- and post-selection
The quantum channel decomposition techniques, which contain the so-called
probabilistic error cancellation and gate/wire cutting, are powerful approach
for simulating a hard-to-implement (or an ideal) unitary operation by
concurrently executing relatively easy-to-implement (or noisy) quantum
channels. However, such virtual simulation necessitates an exponentially large
number of decompositions, thereby significantly limiting their practical
applicability. This paper proposes a channel decomposition method for target
unitaries that have their input and output conditioned on specific quantum
states, namely unitaries with pre- and post-selection. Specifically, we
explicitly determine the requisite number of decomposing channels, which could
be significantly smaller than the selection-free scenario. Furthermore, we
elucidate the structure of the resulting decomposed unitary. We demonstrate an
application of this approach to the quantum linear solver algorithm,
highlighting the efficacy of the proposed method.Comment: 11pages, 5figure
Future Reductions in Polar Cold Air Mass and Cold Air Outbreaks Revealed From Isentropic Analysis
Indicators and trends of polar cold airmass
Trends and variations in the amount of cold airmass in the Arctic and the Northern Hemisphere are evaluated for the 60 year period, 1959–2018. The two indicators are (1) polar cold air mass (PCAM), which is the amount of air below a potential temperature threshold, and (2) negative heat content (NHC), which includes a weighting by coldness. Because the metrics of coldness are based on multiple layers in the atmosphere, they provide a more comprehensive framework for assessment of warming than is provided by surface air temperatures alone. The negative trends of PCAM and NHC are stronger (as a % per decade) when the threshold is 245 K rather than 280 K, indicating that the loss of extremely cold air is happening at a faster rate than the loss of moderately cold air. The loss of cold air has accelerated, as the most rapid loss of NHC has occurred in recent decades (1989–2018). The spatial patterns of the trends of PCAM and NHC provide another manifestation of Arctic amplification. Of the various teleconnection indices, the Atlantic Multidecadal Oscillation shows the strongest correlations with the spatially integrated metrics of moderate coldness. Several Pacific indices also correlate significantly with these indicators. However, the amount of extremely cold air mass does not correlate significantly with the indices of internal variability used here.publishedVersio
Vascular composition data supporting the role of N-3 polyunsaturated fatty acids in the prevention of cardiovascular disease events
AbstractN-3 polyunsaturated fatty acids (PUFAs) are thought to have protective effects against cardiovascular disease. Here, we report the relationship between serum PUFA concentrations and plaque composition, as evaluated by virtual histology-intravascular ultrasound (VH-IVUS). Consecutive patients (n=61) who underwent percutaneous coronary intervention (PCI) were pre-operatively examined using VH-IVUS to assess the composition of culprit plaques. Gray-scale IVUS and VH-IVUS data of fibrous, fibro-fatty, necrotic core, and dense calcium regions of plaques were estimated at the minimal luminal area sites of culprit lesions. Serum levels of high-sensitivity C-reactive protein (hsCRP) and PUFAs, including eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and arachidonic acid (AA), were compared between patients with (ACS, n=27) and without acute coronary syndrome (non-ACS, n=34) before PCI. Multiple logistic regression analysis of the data showed that EPA/AA under the median was more highly associated with ACS than hsCRP over the median. In addition, EPA/AA was negatively correlated with the percentage of fibrous plaque regions and EPA/AA and DHA/AA were positively correlated with the percentage of dense calcium regions in plaques. Furthermore, the correlation index of EPA/AA was the most highly (R=0.513) correlated with the percentage of dense calcium regions in plaques
Global modelling of tungsten impurity transport based on the drift-kinetic equation, Nuclear Fusion
A global kinetic simulation model of collisional impurity transport is developed for evaluating the radial particle flux of tungsten impurity in the edge region of a tokamak plasma. Here, the plasma including the impurity and the background ion is presupposed to be quasi-steady. The simulation model is based on the drift-kinetic equation of the impurity affected by the friction force and the thermal force, which were formulated in the previous study (Homma et al 2016 Nucl. Fusion 56 036009). The model is implemented in a drift-kinetic simulation code. We find that the magnetic drift term in the drift-kinetic equation causes the \u27global effect\u27 on the impurity transport. Here, the global effect means that the solution of the drift-kinetic equation (and also the radial particle flux) on a magnetic flux surface is influenced by the values of the solution all over the edge region
In vivo tracking transplanted cardiomyocytes derived from human induced pluripotent stem cells using nuclear medicine imaging
Introduction: Transplantation of human induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) is a promising treatment for heart failure. Information on long-term cell engraftment after transplantation is clinically important. However, clinically applicable evaluation methods have not yet been established.
Methods: In this study, to noninvasively assess transplanted cell engraftment, human SLC5A5, which encodes a sodium/iodide symporter (NIS) that transports radioactive tracers such as 125I, 18F-tetrafluoroborate (TFB), and 99mTc-pertechnetate (99mTcO4−), was transduced into human induced pluripotent stem cells (iPSCs), and nuclear medicine imaging was used to track engrafted human iPSC-CMs.
Results: To evaluate the pluripotency of NIS-expressing human iPSCs, they were subcutaneously transplanted into immunodeficient rats. Teratomas were detected by 99mTcO4− single photon emission computed tomography (SPECT/CT) imaging. NIS expression and the uptake ability of 125I were maintained in purified human iPSC-CMs. NIS-expressing human iPSC-CMs transplanted into immunodeficient rats could be detected over time using 99mTcO4− SPECT/CT imaging. Unexpectedly, NIS expression affected cell proliferation of human iPSCs and iPSC-derived cells.
Discussion: Such functionally designed iPSC-CMs have potential clinical applications as a noninvasive method of grafted cell evaluation, but further studies are needed to determine the effects of NIS transduction on cellular characteristics and functions
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