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Different approaches to obtaining uncertainty estimates of the North Atlantic Oscillation (NAO) are explored. The resulting estimates are used to enhance the understanding of spatial variability of the NAO over different time periods. Among the parametric and nonparametric approaches investigated in this study, the bootstrap is nonparametric and not confined to the assumption of normally distributed data. It gives physically plausible uncertainty estimates. The NAO uncertainty estimates depend on sample sizes with greater sampling variability as sample size is smaller. The NAO uncertainty varies with time but common features include that the most uncertain values are centered between the centers of action of the NAO and are asymmetric in the zonal direction (more uncertainty in the eastward direction or downstream). The bootstrap can also be used to provide direct measures of uncertainty regarding the location of the NAO action centers. The uncertainty of the location of the NAO action centers not only helps assess the shift in the NAO but also provides evidence of more than two action centers. The methods reported on here could in principle be applied to any EOF-derived climate pattern.

Aims: Diabetic kidney disease (DKD) is the leading cause of end-stage kidney disease. Sodium–glucose cotransporter 2 inhibitors (SGLT2i) showed excellent renoprotective effects; however, the underlying mechanism remains not fully understood. Previous studies have revealed the importance of ferroptosis, which is closely related to oxidative stress, in the progression of DKD. In the current study, we hypothesized that SGLT2i could relieve ferroptosis and thereby alleviate renal injury in DKD due to their antioxidative stress effects. Results: Typical changes of ferroptosis including massive lipid peroxidation, compromised antioxidant capability, and iron overload were found in db/db mice and high glucose/high fat (HG/HF)-treated HK-2 cells. Furthermore, increased expression of hypoxia inducible factor 1α (HIF1α) and heme oxygenase 1 (HO1) was observed in db/db mice and HG/HF-treated HK-2 cells as well. Dapagliflozin treatment significantly ameliorated the ferroptosis-related changes via attenuating overactivation of the HIF1α/HO1 axis in vivo and in vitro. Besides, downregulation of the HIF1α/HO1 axis alleviated ferroptosis, while overexpression of HIF1α and HO1 aggravated ferroptosis induced by HG/HF in HK-2 cells. Innovation and Conclusion: This study revealed that SGLT2i played a renoprotective role in DKD, at least in part, through alleviating HIF1α/HO1-mediated ferroptosis. Antioxid. Redox Signal. 40, 492–509. [ABSTRACT FROM AUTHOR]

Several studies have found an eastward shift in the northern node of the North Atlantic Oscillation (NAO) during the winters of 1978–97 compared to 1958–77. This study focuses on the connection between this shift of the northern node of the NAO and Rossby wave breaking (RWB) for the period 1958–97. It is found that the region of frequent cyclonic RWB underwent a northeastward shift at high latitudes in the latter 20-yr period. On a year-to-year basis, the cyclonic RWB region moves along a southwest–northeast (SW–NE)-directed axis. Both latitude and longitude of the winter maximum frequency of cyclonic RWB occurrence are positively correlated with the NAO index.To investigate the role of location of cyclonic RWB in influencing the NAO pattern, the geographical location of frequent cyclonic RWB is divided into two subdomains located along the SW–NE axis, to the south (SW domain) and east (NE domain) of Greenland. Two composites are assembled as one cyclonic RWB occurrence is detected in one of the two subdomains in 6-hourly instantaneous data. The forcing of the mean flow due to cyclonic RWB within individual subdomains is found to be locally restricted to where the breaking occurs, which is usually near the jet exit region and far removed from the jet core. The difference in the jet between the NE and SW composites resembles the difference in the mean jet between the 1978–97 and 1958–77 periods, which suggests that the change in cyclonic RWB occurrence in the two subdomains is associated with the wobbling of the jet on the decadal time scale.

An objective analysis of tropospheric anticyclonic- and cyclonic-breaking Rossby waves is performed for the Southern Hemisphere in austral summer (December–February) of 1979–2009. The climatology of both anticyclonic and cyclonic Rossby wave breaking (RWB) frequency is presented. The frequency of anticyclonic RWB is highest in an extended region of the Eastern Hemisphere on the anticyclonic side of the jet, while that of cyclonic RWB is highest on the cyclonic side of the jet. A composite analysis of anticyclonic and cyclonic RWB shows how they contribute to a positive and negative southern annual mode (SAM) index, respectively. The time series of austral summer anticyclonic RWB occurrence has a trend that closely matches the trend in the SAM index.Regions of RWB that are significantly correlated with the SAM index are objectively determined. Even though several such regions are identified, only two regions (anticyclonic and cyclonic) covering 17% of the area of the hemisphere are required in a linear regression model of the SAM index. The anticyclonic RWB region is zonally extended at 45°S and explains 78% of the variability of the summer-mean SAM index. The cyclonic region is located at high latitudes somewhat decoupled from the jet, in the longitudinal sector of the Indian Ocean. On synoptic time scales, transitions of the SAM index respond to RWB without time lag.ENSO cycles present an interesting zonal asymmetry to the distribution of Southern Hemispheric RWB in the central Pacific. Anticyclonic RWB is increased in the tropical/subtropical central Pacific during La Niña compared to El Niño. This increase is related to the strong local decrease in zonal wind. At the same time, anticyclonic RWB outside the central Pacific is increased in frequency poleward and decreased in frequency equatorward of 42°S, corresponding to a positive SAM index.

In the present study, a series of derivatives and analogs of daidzein were designed and synthesized to investigate cholinesterase inhibition and blood–brain barrier permeability. The enzyme assay showed that most of the compounds containing a tertiary amine group exhibit moderate cholinesterase inhibition, 7‐hydroxychromone derivatives (absence of B ring of daidzein scaffold) only have a weaker bioactivity, while those compounds without the tertiary amine group have no bioactivity. Among them compound 15a (4'‐N,N‐dimethylaminoethoxy‐7‐methoxyisoflavone) appeared the best inhibitory activity (IC50: 2.14 ± 0.31 μmol/L) and higher selectivity for AChE over BuChE (Ratio: 7.07). It was selected for the further investigation by UPLC‐MS/MS. The results show that CBrain/Serum of compound 15a in mice was more than 2.87 within 240 min. This discovery may provide worthy information for the future development of central nervous drugs including but not limited to cholinesterase inhibitors. [ABSTRACT FROM AUTHOR]