252 research outputs found

    Long-term changes in weekday-holiday temperature difference in central Tokyo: Analysis since the early 20th century

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    To analyze the long-term trends of weekday-holiday temperature differences in Tokyo, Japan, meteorological data obtained from 1897 to 2021 were used. Negative departure of temperature on holidays from that on weekdays ( T ) was determined for the period after the 1960s. From 1970 to 1990, T had a value of –0.15 to –0.2 °C and –0.2 to –0.3 °C for the daily mean and daily maximum temperatures, respectively. Moreover, a decline in trend of T emerged after the 2000s. Prior to 1960 T was generally less; however, positive values of approximately 0.1 °C were determined as the daily maximum temperature from 1920 to early 1930s, accompanied by a positive anomaly of the frequency of light precipitation defined by a daily precipitation between 0.1 and 1 mm

    Dominant aerosol processes during high-pollution episodes over Greater Tokyo

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    This paper studies two high-pollution episodes over Greater Tokyo: 9 and 10 December 1999, and 31 July and 1 August 2001. Results obtained with the chemistry-transport model (CTM) Polair3D are compared to measurements of inorganic PM2.5. To understand to which extent the aerosol processes modeled in Polair3D impact simulated inorganic PM2.5, Polair3D is run with different options in the aerosol module, e.g. with/without heterogeneous reactions. To quantify the impact of processes outside the aerosol module, simulations are also done with another CTM (CMAQ). In the winter episode, sulfate is mostly impacted by condensation, coagulation, long-range transport, and deposition to a lesser extent. In the summer episode, the effect of long-range transport largely dominates. The impact of condensation/evaporation is dominant for ammonium, nitrate and chloride in both episodes. However, the impact of the thermodynamic equilibrium assumption is limited. The impact of heterogeneous reactions is large for nitrate and ammonium, and taking heterogeneous reactions into account appears to be crucial in predicting the peaks of nitrate and ammonium. The impact of deposition is the same for all inorganic PM2.5. It is small compared to the impact of other processes although it is not negligible. The impact of nucleation is negligible in the summer episode, and small in the winter episode. The impact of coagulation is larger in the winter episode than in the summer episode, because the number of small particles is higher in the winter episode as a consequence of nucleation.Comment: Journal of Geophysical Research D: Atmospheres (15/05/2007) in pres

    Influence of Nearby Plants and Artificial Structures on the Surface Air Temperature Statistics : An in-situ Measurement at Central Tokyo (Otemachi) throughout Years

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    In order to clarify the influence of obstacles on temperature measurement, two years\u27 continuous observation was made in the meteorological enclosure of the Japan Meteorological Agency in central Tokyo (Otemachi), by installing an extra thermometer at a spot that was surrounded by trees and was 20 m distant from the thermometer for operational observation. In the early afternoon of the warm season, the temperature at the spot surrounded by trees was found to be higher than the operational temperature. The temperature difference at 15JST was about 0.5 degrees Celsius on theaverage, and was correlated with daily solar radiation with a correlation coefficient of over 0.7 from March to September. On the other hand, difference of nighttime temperature was generally small, so that the monthly mean difference of daily mean temperatures was less than 0.1 degree Celsius for all the months of the year

    The roles of metformin and pravastatin on placental endoplasmic reticulum stress and placental growth factor in human villous-Like trophoblastic BeWo cells

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    Preeclampsia (PE) is related to an imbalance of angiogenic factors. Placental growth factor (PlGF) is reduced in early onset PE. Recent evidence indicates that metformin and statins may suppress endoplasmic reticulum (ER) stress. We previously reported that the unfolded protein response activated by ER stress down-regulated PlGF protein expression and predicted these drugs could prevent placental ER stress and up-regulate PlGF protein expression in trophoblast-like cells. In this study, we aimed to establish the effects of these drugs on PlGF and activating transcription factor 4 (ATF4) protein expression. We confirmed that PlGF messenger RNA (mRNA) levels were decreased under ER stress induced by thapsigargin and that ATF4 mRNA was increased under the same conditions and then administered metformin to it. Transcript analysis showed increased PlGF mRNA compared with thapsigargin only treatment and that this was dependent on metformin levels. Under ER stress, western blot showed high levels of ATF4 and phosphorylated-eukaryotic initiation factor 2 subunit α (p-eIF2α) but low levels of PlGF protein. By contrast, compared with thapsigargin alone, ATF4 and p-eIF2α levels were low and PlGF levels were high when metformin and thapsigargin were given, but these were again dependent on metformin concentrations. Western blot also confirmed that pravastatin attenuated ER stress and increased PlGF protein expression. In conclusion, metformin and pravastatin suppressed ER stress and restored PlGF levels in trophoblast-like cells. However, although these results indicate that these drugs have a potential for preventing or treating PE, the lack of clarity on the mechanism requires further study

    High-Throughput SuperSAGE for Digital Gene Expression Analysis of Multiple Samples Using Next Generation Sequencing

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    We established a protocol of the SuperSAGE technology combined with next-generation sequencing, coined “High-Throughput (HT-) SuperSAGE”. SuperSAGE is a method of digital gene expression profiling that allows isolation of 26-bp tag fragments from expressed transcripts. In the present protocol, index (barcode) sequences are employed to discriminate tags from different samples. Such barcodes allow researchers to analyze digital tags from transcriptomes of many samples in a single sequencing run by simply pooling the libraries. Here, we demonstrated that HT-SuperSAGE provided highly sensitive, reproducible and accurate digital gene expression data. By increasing throughput for analysis in HT-SuperSAGE, various applications are foreseen and several examples are provided in the present study, including analyses of laser-microdissected cells, biological replicates and tag extraction using different anchoring enzymes

    Protein Kinase C Activation Has Distinct Effects on the Localization, Phosphorylation and Detergent Solubility of the Claudin Protein Family in Tight and Leaky Epithelial Cells

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    We have previously shown that protein kinase C (PKC) activation has distinct effects on the structure and barrier properties of cultured epithelial cells (HT29 and MDCK I). Since the claudin family of tight junction (TJ)-associated proteins is considered to be crucial for the function of mature TJ, we assessed their expression patterns and cellular destination, detergent solubility and phosphorylation upon PKC stimulation for 2 or 18 h with phorbol myristate acetate (PMA). In HT29 cells, claudins 1, 3, 4 and 5 and possibly claudin 2 were redistributed to apical cell–cell contacts after PKC activation and the amounts of claudins 1, 3 and 5, but not of claudin 2, were increased in cell lysates. By contrast, in MDCK I cells, PMA treatment resulted in redistribution of claudins 1, 3, 4 and 5 from the TJ and in reorganization of the proteins into more insoluble complexes. Claudins 1 and 4 were phosphorylated in both MDCK I and HT29 cells, but PKC-induced changes in claudin phosphorylation state were detected only in MDCK I cells. A major difference between HT29 and MDCK I cells, which have low and high basal transepithelial electrical resistance, respectively, was the absence of claudin 2 in the latter. Our findings show that PKC activation targets in characteristic ways the expression patterns, destination, detergent solubility and phosphorylation state of claudins in epithelial cells with different capacities to form an epithelial barrier

    Future change of daily precipitation indices in Japan: a stochastic weather generator-based bootstrap approach to provide probabilistic climate information

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    This study proposes the stochastic weather generator (WG)-based bootstrap approach to provide the probabilistic climate change information on mean precipitation as well as extremes, which applies a WG (i.e., LARS-WG) to daily precipitation under the present-day and future climate conditions derived from dynamical and statistical downscaling models. Additionally, the study intercompares the precipitation change scenarios derived from the multimodel ensemble for Japan focusing on five precipitation indices (mean precipitation, MEA; number of wet days, FRE; mean precipitation amount per wet day, INT; maximum number of consecutive dry days, CDD; and 90th percentile value of daily precipitation amount in wet days, Q90). Three regional climate models (RCMs: NHRCM, NRAMS and TWRF) are nested into the high-resolution atmosphere-ocean coupled general circulation model (MIROC3.2HI AOGCM) for A1B emission scenario. LARS-WG is validated and used to generate 2000 years of daily precipitation from sets of grid-specific parameters derived from the 20-year simulations from the RCMs and statistical downscaling model (SDM: CDFDM). Then 100 samples of the 20-year of continuous precipitation series are resampled, and mean values of precipitation indices are computed, which represents the randomness inherent in daily precipitation data. Based on these samples, the probabilities of change in the indices and the joint occurrence probability of extremes (CDD and Q90) are computed. High probabilities are found for the increases in heavy precipitation amount in spring and summer and elongated consecutive dry days in winter over Japan in the period 2081-2100, relative to 1981-2000. The joint probability increases in most areas throughout the year, suggesting higher potential risk of droughts and excess water-related disasters (e. g., floods) in a 20 year period in the future. The proposed approach offers more flexible way in estimating probabilities of multiple types of precipitation extremes including their joint probability compared to conventional approaches
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