138 research outputs found

    Nitric Oxide Fluxes from Upland Soils in Central Hokkaido, Japan

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    Human movement decisions during Coronavirus Disease 2019

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    To predict epidemics' future course in changing situations, understanding human mobility patterns is important, notwithstanding decision-making process uncertainties owing to difficulties in quantifying people's mobility change decision timings, which make the mobility-epidemic causal relationship unclear. We used the 'mobility avoidance index' to investigate time-series changes during Japan's Coronavirus Disease 2019 (eight waves until February 2023) as a previous study, which measured this index using accommodation reservation data-booking/cancellation timings-was able to quantify the timing of decision-making for mobility changes. Our analyses revealed two general patterns: 1) the index increased/decreased proportional to logarithms of reported cases during the first wave, conforming with Weber-Fechner's psychophysics law; 2) its slope against the change in the number of reported cases had similar values among the waves, but its intercepts changed as the waves passed, suggesting that people neglected reported cases lower than a certain threshold for behavioural decision-making. We shifted the threshold level as the waves passed, and named this pattern 'shift of negligible epidemic' rule. It is the first pattern quantitatively observed, that possesses decision making tendencies for future mobility avoidance. Our findings contribute to constructing a mathematical model, which simultaneously considers epidemics and human mobility dynamics

    Low-temperature synthesis of crystalline GeSn with high Sn concentration by electron excitation effect

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    The low-temperature synthesis of high-Sn-concentration GeSn is challenging in realizing flexible thin-film transistors and solar cells. Because of athermal processes, irradiation with energetic particles is anticipated to significantly reduce the processing temperature for device fabrication. Here, we demonstrated that polycrystalline Ge with ~30 at. % Sn can be realized at room temperature by the electron-beam-induced recrystallization of amorphous GeSn. We found that inelastic electronic stopping, the so-called electron excitation effect, plays an important role in the recrystallization of amorphous GeSn

    Combined Omics Approaches Reveal the Roles of Non-canonical WNT7B Signaling and YY1 in the Proliferation of Human Pancreatic Progenitor Cells

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    ヒト膵臓細胞の増殖メカニズムを解明 --糖尿病治療に向けて前進--. 京都大学プレスリリース. 2020-10-30.The proliferation of human pancreatic progenitor cells (PPCs) is critical for developing cell therapies for diabetes. Here, using transcriptome analysis combined with small interfering RNA (siRNA) screening, we revealed that WNT7B is a downstream growth factor of AT7867, a compound known to promote the proliferation of PPCs generated from human pluripotent stem cells. Feeder cell lines stably expressing mouse Wnt7a or Wnt7b, but not other Wnts, enhanced PPC proliferation in the absence of AT7867. Importantly, Wnt7a/b ligands did not activate the canonical Wnt pathway, and PPC proliferation depended on the non-canonical Wnt/PKC pathway. A comparison of the phosphoproteome in response to AT7867 or a newly synthesized AT7867 derivative uncovered the function of YY1 as a transcriptional regulator of WNT7B. Overall, our data highlight unknown roles of non-canonical WNT7B/PKC signaling and YY1 in human PPC proliferation and will contribute to the stable supply of a cell source for pancreatic disease modeling and therapeutic applications

    Brain Activation During Autobiographical Memory Retrieval with Special Reference to Default Mode Network

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    Recent neuroimaging studies have suggested that brain regions activated during retrieval of autobiographical memory (ABM) overlap with the default mode network (DMN), which shows greater activation during rest than cognitively demanding tasks and is considered to be involved in self-referential processing. However, detailed overlap and segregation between ABM and DMN remain unclear. This fMRI study focuses first on revealing components of the DMN which are related to ABM and those which are unrelated to ABM, and second on extracting the neural bases which are specifically devoted to ABM. Brain activities relative to rest during three tasks matched in task difficulty assessed by reaction time were investigated by fMRI; category cued recall from ABM, category cued recall from semantic memory, and number counting task. We delineated the overlap between the regions that showed less activation during semantic memory and number counting relative to rest, which correspond to the DMN, and the areas that showed greater or less activation during ABM relative to rest. ABM-specific activation was defined as the overlap between the contrast of ABM versus rest and the contrast of ABM versus semantic memory. The fMRI results showed that greater activation as well as less activation during ABM relative to rest overlapped considerably with the DMN, indicating that the DMN is segregated to the regions which are functionally related to ABM and the regions which are unrelated to ABM. ABM-specific activation was observed in the left-lateralized brain regions and most of them fell within the DMN

    An fMRI Study of Word Reading and Colour Recognition in Different Quadrant Fields

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    This fMRI study analyzed activations for processing of word and colour, which were presented in each of the four quadrants, to investigate anatomical segregation between colour and orientation processing and also to examine the effect of visual stimulus position on brain activations. Main effect of visual category was found in the bilateral extrastriate cortices extending to the left visual word form area (word > colour) and small area of the right ventrolateral prefrontal cortex (colour > word). ROI analysis showed that there was a tendency that V4α, not V4/8, showed a greater response to colours than to words. Main effect of visual fields was found in early visual areas, which showed greater responses to the left than to the right field stimuli and also to the lower than to the upper field stimuli. No significant interactions between visual category and visual fields were found

    Prolongation of total permissible circulatory arrest duration by deep hypothermic intermittent circulatory arrest

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    AbstractObjective: We determined whether the duration of permissible circulatory arrest could be prolonged by deep hypothermic intermittent circulatory arrest. Methods: Twenty-five beagles were cooled on bypass to 18° C to initiate deep hypothermia that was maintained for 3 hours. Five protocols were then studied: group 1, uninterrupted bypass during hypothermia; group 2, arrest for 40 minutes during hypothermia; group 3, arrest for 60 minutes during hypothermia; group 4, arrest for 80 minutes during hypothermia; and group 5, intermittent circulatory arrest, consisting of six cycles of 20 minutes of arrest followed by 10 minutes of systemic recirculation during hypothermia (total, 120 minutes of arrest). The oxyhemoglobin concentration in the brain was measured with near infrared spectrophotometry. Results: In groups 2, 3, and 4, the oxyhemoglobin concentration in the brain decreased continuously after arrest, finally reaching a plateau after 24.9 ± 1.2 minutes. This finding suggested that the available cerebral oxyhemoglobin was depleted. In contrast, the available cerebral oxyhemoglobin was not depleted during hypothermic intermittent arrest in group 5. The mitochondrial respiratory control index was significantly lower in group 4 than in the other groups (p < 0.05). However, there were no significant differences in the respiratory control index for groups 1, 2, 3, and 5. Moreover, the formation of brain edema was significantly lower in group 5 than in the other groups (p < 0.05). Conclusions: These results indicate that deep hypothermic intermittent arrest can increase the duration of total permissible circulatory arrest and will be a useful modality when prolonged arrest is anticipated. (J Thorac Cardiovasc Surg 1998;116:163-70

    Age- and sex-related differences of muscle cross-sectional area in iliocapsularis: a cross-sectional study

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    [Background] This study aimed to determine in how many individuals the iliocapsularis muscle (IC) could be identified on magnetic resonance imaging (MRI) and whether age and sex are associated with the cross-sectional area (CSA) of the IC. [Methods] Thirty-seven healthy younger adults and 40 healthy older adults were assigned to four groups: 1) 20 younger men; 2) 17 younger women; 3) 20 older men; and 4) 20 older women. The CSAs of the IC, IP, the rectus femoris (RF) and the quadriceps (QUAD) were quantified on an axial MRI. [Results] The number of individuals with the identified IC was n = 17 (85.0%) of 20 younger men, n = 15 (88.2%) of 17 younger women, n = 18 (90.0%) of 20 older men, and 19 (95.0%) of 20 older women. Our results showed the main effect of sex, but not age, in the CSA of the IC. The men-groups had larger CSA of the IC than the women-groups; however, no difference in CSA of the IC was found between the younger and older groups. Meanwhile, the main effects of age and sex were found for the IP, RF, and QUAD; thus, younger or men groups have larger CSAs of the three muscles than the older or women groups. The IC muscle can be discriminated in 85% – 95% of healthy individuals. [Conclusion] Although sex and age are associated with the CSA of lower-limb muscles other than the IC, only sex is associated with the CSA of the IC
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