南大洋110E度線の季節海氷域におけるpCO2の変動

第6回極域科学シンポジウム分野横断セッション：[IB1] 海氷域における生物地球化学的研究11月17日（火）　国立極地研究所１階交流アトリウ

Mooring measurement of sea ice and ocean in the Cape Darnley Polynya, Antarctica

第2回極域科学シンポジウム/第34回気水圏シンポジウム 11月17日（木） 統計数理研究所 セミナー室

Hyperoxemia and excess oxygen use in early acute respiratory distress syndrome : Insights from the LUNG SAFE study

Publisher Copyright: © 2020 The Author(s). Copyright: Copyright 2020 Elsevier B.V., All rights reserved.Background: Concerns exist regarding the prevalence and impact of unnecessary oxygen use in patients with acute respiratory distress syndrome (ARDS). We examined this issue in patients with ARDS enrolled in the Large observational study to UNderstand the Global impact of Severe Acute respiratory FailurE (LUNG SAFE) study. Methods: In this secondary analysis of the LUNG SAFE study, we wished to determine the prevalence and the outcomes associated with hyperoxemia on day 1, sustained hyperoxemia, and excessive oxygen use in patients with early ARDS. Patients who fulfilled criteria of ARDS on day 1 and day 2 of acute hypoxemic respiratory failure were categorized based on the presence of hyperoxemia (PaO2 > 100 mmHg) on day 1, sustained (i.e., present on day 1 and day 2) hyperoxemia, or excessive oxygen use (FIO2 ≥ 0.60 during hyperoxemia). Results: Of 2005 patients that met the inclusion criteria, 131 (6.5%) were hypoxemic (PaO2 < 55 mmHg), 607 (30%) had hyperoxemia on day 1, and 250 (12%) had sustained hyperoxemia. Excess FIO2 use occurred in 400 (66%) out of 607 patients with hyperoxemia. Excess FIO2 use decreased from day 1 to day 2 of ARDS, with most hyperoxemic patients on day 2 receiving relatively low FIO2. Multivariate analyses found no independent relationship between day 1 hyperoxemia, sustained hyperoxemia, or excess FIO2 use and adverse clinical outcomes. Mortality was 42% in patients with excess FIO2 use, compared to 39% in a propensity-matched sample of normoxemic (PaO2 55-100 mmHg) patients (P = 0.47). Conclusions: Hyperoxemia and excess oxygen use are both prevalent in early ARDS but are most often non-sustained. No relationship was found between hyperoxemia or excessive oxygen use and patient outcome in this cohort. Trial registration: LUNG-SAFE is registered with ClinicalTrials.gov, NCT02010073publishersversionPeer reviewe

Arctic and Antarctic sea ice acts as a sink for atmospheric CO2 during periods of snowmelt and surface flooding

In this study, we present evidence that Antarctic and Arctic sea ice act as sink for atmospheric CO2 during periods of snowmelt and surface flooding. The CO2 flux measured directly at the flooded sea ice surface (Fflood) constituted a net CO2 sink of −1.1 ± 0.9 mmol C m−2 d−1 (mean ± 1 SD), which was an order of magnitude higher than the flux measured at the snow‐air surface (Fsnow) and bare ice surface (Fice). The Fsnow/Fflood ratio decreased with increasing water equivalent of snow and superimposed‐ice, suggesting that the properties of snow and superimposed‐ice formation affect the magnitude of the CO2 flux. The Fsnow/Fflood ratio ranged from 0.1 to 0.5, illustrating that 50–90% of the potential flux at the flooded surface was reduced due to the presence of snow/superimposed‐ice. Hence, snow cover properties and superimposed‐ice play an important role in the CO2 fluxes across the sea ice‐snow‐atmosphere interface

The Effect of Basal Melting of the Shirase Glacier Tongue on the CO2 System in Lutzow-Holm Bay, East Antarctica

To clarify the effect of basal melting of ice tongues/ice shelf on the CO2 system in the Antarctic continental margin, seawater samples were collected for analysis of dissolved inorganic carbon (DIC), total alkalinity (TA), nutrients, chlorophyll a (chl.a), and oxygen isotopic ratios at the ice front of the Shirase Glacier Tongue (SGT) in Lutzow-Holm Bay (LHB), East Antarctica during the summers of 2017 and 2018. At depths greater than similar to 20 dbar in LHB, CO2 system parameters were strongly influenced by the dilution effect of SGT basal melting and the inflow of modified Circumpolar Deep Water (mCDW). The distributions of DIC and TA agreed well with an offshore origin of mCDW that flowed beneath the SGT and mixing of basal meltwater and mCDW beneath the SGT. The fraction of SGT meltwater was highest at the station near the ice front. Dilution by SGT basal meltwater reduced the partial pressure of CO2 in the mCDW from 431 to 387 mu atm. The water then became a sink rather than source of atmospheric CO2. In the sea surface, DIC and TA were strongly influenced by biological processes. Salinity-normalized DIC decreased with the increase of salinity-normalized TA in accord with 106:16 C:N molar stoichiometry; the chl.a concentration at the sea surface was as high as 31 mu g L-1

Spatiotemporal distribution of two mackerel species, Scomber japonicus and Scomber australasicus, in the Bungo Channel, western Japan

2007-2017年における豊後水道でのマサバ・ゴマサバの漁獲情報をもとに，両種の分布特性を調べた。豊後水道の北部ではマサバ，南部ではゴマサバが主体で漁獲されていた。東（愛媛県）側ではより北側にゴマサバが出現し，水温環境の水道東西での非対称性との関連性が示唆された。また，両種の当歳魚は4月から6月にかけて1歳魚以上に比べて沿岸域に分布が偏っていたが，7月には沖合にも出現するようになり，成長に伴い沿岸から沖合へ生息場所を拡げることが示唆された。To reveal the distribution patterns of mackerel in the Bungo Channel, western Japan, we investigated catch statistics and specimens of chub mackerel Scomber japonicus and spotted mackerel Scomber australasicus sampled at fish markets from 2007 to 2017. Chub mackerel were caught mainly in the northern part of the Bungo Channel while spotted mackerel were caught in the southern part of the channel. Spotted mackerel were observed at higher latitude in the eastern channel (Ehime Prefecture) compared to the western side (Oita Prefecture). This pattern suggested a correlation with the asymmetry in water temperature between the eastern and western sides of the channel. The distribution of 0-year-old mackerel was observed chiefly around nearshore areas from April to June, and thereafter it gradually shifted to offshore areas in July, indicating that 0-year-old fish expanded their habitat to offshore waters as they grew

Conformational change in full-length mouse prion: a site-directed spin-labeling study.

The structure of the mouse prion (moPrP) was studied using site-directed spin-labeling electron spin resonance (SDSL-ESR). Since a previous NMR study by Hornemanna et al., [Hornemanna, Korthb, Oeschb, Rieka, Widera, Wüthricha, Glockshubera, Recombinant full-length murine prion protein, mPrP (23–231): purification and spectroscopic characterization, FEBS Lett. 413 (1997) 277–281] has indicated that N96, D143, and T189 in moPrP are localized in a Cu2+ binding region, Helix1 and Helix2, respectively, three recombinant moPrP mutations (N96C, D143C, and T189C) were expressed in an Escherichia coli system, and then refolded by dialysis under low pH and purified by reverse-phase HPLC. By using the preparation, we succeeded in preserving a target cystein residue without alteration of the α-helix structure of moPrP and were able to apply SDSL-ESR with a methane thiosulfonate spin label to the full-length prion protein. The rotational correlation times (τ) of 1.1, 3.3, and 4.8 ns were evaluated from the X-band ESR spectra at pH 7.4 and 20 °C for N96R1, D143R1, and T189R1, respectively. τ reflects the fact that the Cu2+ binding region is more flexible than Helix1 or Helix2. ESR spectra recorded at various temperatures revealed two phases together with a transition point at around 20 °C in D143R1 and T189R1, but not in N96R1. With the variation of pH from 4.0 to 7.8, ESR spectra of T189R1 at 20 °C showed a gradual increase of τ from 2.9 to 4.8 ns. On the other hand, the pH-dependent conformational changes in N96R1 and D143R1 were negligible. These results indicated that T189 located in Helix2 possessed a structure sensitive to physiological pH changes; simultaneously, N96 in the Cu2+ binding region and D143 in Helix1 were conserved