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Abstract Contrasting the extensive research on summer atmospheric rivers (ARs) in the Antarctic Peninsula (AP), winter AR impacts are less understood. This study examines a unique warming event from 1 to 3 July 2023, using in situ winter observations and ERA5 reanalysis. On 2 July, Frei station experienced an extreme warm event with a temperature of 2.7°C and a significant rise in the freezing level, coinciding with winter rainfall. A pressure dipole pattern over the AP, with contrasting circulations over Bellingshausen and Weddell Seas, facilitated an AR, carrying warm, humid air initially from South America/Atlantic and then the southeast Pacific. This shift resulted in anomalous water stable isotope composition in precipitation. Trends suggest a strengthening winter pressure dipole, associated with increased AR frequency and higher temperatures in northern AP. These findings highlight the importance of winter observations in exploring AR impacts, bridging knowledge gaps about winter AR behaviors.

In February 2023, the sea-ice extent around Antarctica dropped to 1.79×106 km2, setting a satellite-era record low for the second straight year. Recent records stress the need for further research into the factors behind record-breaking Antarctic sea-ice anomalies. By influencing the circumpolar westerly winds, the stratospheric polar vortex has played a major role in the Antarctic surface climate in recent decades. However, the footprint of the polar vortex variability in the year-to-year changes in the Antarctic sea-ice cover remains obscured. Here, we use satellite retrievals and reanalysis data to study the response of the sea-ice extent around Antarctica to changes in the polar vortex strength. We focus on the last 2 decades that saw sharp changes in the stratospheric zonal flow, the tropospheric westerly winds and the sea-ice cover (the latter climbed to record highs in 2013 and 2014 before dropping to record lows in 2017, 2022 and 2023). Our results suggest that this unprecedented interannual variability is noticeably influenced by the polar vortex dynamics. The signature of the stratosphere–troposphere coupling is apparent in recent records (highs and lows) in the sea-ice extent around Antarctica.

This study investigated the spatiotemporal variabilities in nitrogen dioxide (NO2), formaldehyde (HCHO), ozone (O3), and light-absorbing aerosols within the Greater Tokyo Area, Japan, which is the most populous metropolitan area in the world. The analysis is based on total tropospheric column, partial tropospheric column (within the boundary layer), and in situ observations retrieved from multiple platforms as well as additional information obtained from reanalysis and box model simulations. This study mainly covers the 2013–2020 period, focusing on 2020 when air quality was influenced by the coronavirus 2019 (COVID-19) pandemic. Although total and partial tropospheric NO2 columns were reduced by an average of about 10 % in 2020, reductions exceeding 40 % occurred in some areas during the pandemic state of emergency. Light-absorbing aerosol levels within the boundary layer were also reduced for most of 2020, while smaller fluctuations in HCHO and O3 were observed. The significantly enhanced degree of weekly cycling of NO2, HCHO, and light-absorbing aerosol found in urban areas during 2020 suggests that, in contrast to other countries, mobility in Japan also dropped on weekends. We conclude that, despite the lack of strict mobility restrictions in Japan, widespread adherence to recommendations designed to limit the COVID-19 spread resulted in unique air quality improvements.

Here, we present radiative forcing (RF) estimates by snow algae in the Antarctic Peninsula (AP) region from multi-year measurements of solar radiation and ground-based hyperspectral characterization of red and green snow algae collected during a brief field expedition in austral summer 2018. Our analysis includes pigment content from samples at three bloom sites. Algal biomass in the snow and albedo reduction are well-correlated across the visible spectrum. Relative to clean snow, visibly green patches reduce snow albedo by ∼40 % and red patches by ∼20 %. However, red communities absorb considerably more light per milligram of pigment compared to green communities, particularly in green wavelengths. Based on our study results, it should be possible to differentiate red and green algae using Sentinel-2 bands in blue, green and red wavelengths. Instantaneous RF averages were double for green (180 W m−2) vs. red communities (88 W m−2), with a maximum of 228 W m−2. Based on multi-year solar radiation measurements at Palmer Station, this translated to a mean daily RF of ∼26 W m−2 (green) and ∼13 W m−2 (red) during peak growing season – on par with midlatitude dust attributions capable of advancing snowmelt. This results in ∼2522 m3 of snow melted by green-colored algae and ∼1218 m3 of snow melted by red-colored algae annually over the summer, suggesting snow algae play a significant role in snowmelt in the AP regions where they occur. We suggest impacts of RF by snow algae on snowmelt be accounted for in future estimates of Antarctic ice-free expansion in the AP region.

Observations from the new Japanese geostationary satellite Himawari-8 permit quasi-real-time estimation of global shortwave radiation at an unprecedented temporal resolution. However, accurate comparisons with ground-truthing observations are essential to assess their uncertainty. In this study, we evaluated the Himawari-8 global radiation product AMATERASS using observations recorded at four SKYNET stations in Japan and, for certain analyses, from the surface network of the Japanese Meteorological Agency in 2016. We found that the spatiotemporal variability of the satellite estimates was smaller than that of the ground observations; variability decreased with increases in the time step and spatial domain. Cloud variability was the main source of uncertainty in the satellite radiation estimates, followed by direct effects caused by aerosols and bright albedo. Under all-sky conditions, good agreement was found between satellite and ground-based data, with a mean bias in the range of 20–30 W m−2 (i.e., AMATERASS overestimated ground observations) and a root mean square error (RMSE) of approximately 70–80 W m−2. However, results depended on the time step used in the validation exercise, on the spatial domain, and on the different climatological regions. In particular, the validation performed at 2.5 min showed largest deviations and RMSE values ranging from about 110 W m−2 for the mainland to a maximum of 150 W m−2 in the subtropical region. We also detected a limited overestimation in the number of clear-sky episodes, particularly at the pixel level. Overall, satellite-based estimates were higher under overcast conditions, whereas frequent episodes of cloud-induced enhanced surface radiation (i.e., measured radiation was greater than expected clear-sky radiation) tended to reduce this difference. Finally, the total mean bias was approximately 10–15 W m−2 under clear-sky conditions, mainly because of overall instantaneous direct aerosol forcing efficiency in the range of 120–150 W m−2 per unit of aerosol optical depth (AOD). A seasonal anticorrelation between AOD and global radiation differences was evident at all stations and was also observed within the diurnal cycle.

Sudden changes in stratospheric chlorine species in the polar northern atmosphere, caused by the Solar Proton Events (SPEs) of 17 and 20 January 2005, have been investigated and compared with version 4 of the Whole Atmosphere Community Climate Model (WACCM4). We used Aura Microwave Limb Sounder (MLS) measurements to monitor the variability of ClO, HCl, HOCl and Michelson Interferometer for Passive Atmospheric Sounder (MIPAS) on ENVISAT to retrieve ClONO2. SPE-induced chlorine activation has been identified. HCl decrease occurred at nearly all the investigated altitudes (i.e., 10–0.5 hPa) with the strongest decrease (of about 0.25 ppbv) on 21 January. HOCl was found to be the main active chlorine species under nighttime conditions (with increases of more than 0.2 ppbv) whereas both HOCl and ClO enhancements (about 0.1 ppbv) have been observed at the polar night terminator. Further, small ClO decreases (of less than 0.1 ppbv) and ClONO2 enhancements (about 0.2 ppbv) have been observed at higher latitudes (i.e., at nighttime) roughly above 2 hPa. While WACCM4 reproduces most of the SPE-induced variability in the chlorine species fairly well, in some particular regions discrepancies between the modeled and measured temporal evolution of the abundances of chlorine species were found. HOCl changes are modelled very well with respect to both magnitude and geographic distribution. ClO decreases are reproduced at high latitudes, whereas ClO enhancements in the terminator region are underestimated and attributed to background variations. WACCM4 also reproduces the HCl depletion in the mesosphere but it does not show the observed decrease below about 2 hPa. Finally, WACCM4 simulations indicate that the observed ClONO2 increase is dominated by background variability, although SPE-induced production might contribute by 0.1 ppbv.

To illustrate the effect of a cellulose-binding domain (CBD) on the enzymatic characteristics of non-cellulolytic exoglucanases, 10 different recombinant enzymes were constructed combining theSaccharomyces cerevisiaeexoglucanases, EXG1 and SSG1, with the CBD2 from theTrichoderma reeseicellobiohydrolase, CBH2, and a linker peptide. The enzymatic activity of the recombinant enzymes increased with the CBD copy number. The recombinant enzymes, CBD2-CBD2-L-EXG1 and CBD2-CBD2-SSG1, exhibited the highest cellobiohydrolase activity (17.5 and 16.3 U mg-1 respectively) on Avicel cellulose, which is approximately 1.5- to 2-fold higher than the native enzymes. The molecular organisation of CBD in these recombinant enzymes enhanced substrate affinity, molecular flexibility and synergistic activity, contributing to their elevated action on the recalcitrant substrates as characterised by adsorption, kinetics, thermostability and scanning electron microscopic analysis. [ABSTRACT FROM AUTHOR]

To determine the efficacy and safety of the Ologen collagen matrix adjunctive to Ahmed valve surgery. A randomized prospective multicentre clinical trial involving 58 patients that were followed for one year. Conventional surgery with Ahmed valve was performed in 31 eyes (Control group/CG) and in 27 Ologen (Ologen group/OG) was placed over the valve's plate. Baseline data: age, corneal thickness, intraocular pressure(IOP) and antiglaucoma medications.Postoperative data (days 1, 7 and months 1, 3, 6 and 12): IOP, antiglaucoma medications, visual acuity and complications were recorded. Frequency of hypertensive phase, complete and qualified success and survival rate were studied. No differences were found between CG and OG in the baseline data. The only difference between groups was a significantly lower IOP at day 1. No other differences were found in the follow-up between groups. Hypertensive phase (56%CG and 55%OG, p = 0,947), complete success 28,6%CG and 30,4%OG (p = 0,88) and qualified success 96,4% and 95,9%(p = 0,794). Survival rates at 1 year were 76,7%(CG) and 69,2%(OG)(p = 0,531). 38,7% of patients in the CG suffered some complication during follow-up and 61,5% in OG(p = 0,086). Ologen does not increase safety or efficacy in Ahmed valve surgery at one-year follow-up. This is the first study that shows no benefit of Ologen adjunctive to this surgery.

A previously described method for the analysis of hair has been modified to include analysis for amphetamines, benzodiazepines, cocaine and its metabolites, methadone and its metabolite, and phencyclidine in addition to opiates on a sample of hair. The samples of hair were washed twice with dichloromethane and cut into 1-mm segments prior to extraction with methanol at 45 degrees C for 18 h. The extracts were split into two parts; both were evaporated to dryness. One half of the extract was derivatized using MBTFA for analysis of amphetamines, and the other half was derivatized using MTBSTFA for analysis of the remaining drugs. The extracts were analyzed using electron impact gas chromatography-mass spectrometry operating in selected ion monitoring mode. In total, 18 drugs of abuse/metabolites could be detected. The method was used to screen 20 hair samples from patients attending a methadone-maintenance clinic.

Due to its short half life and high tryptophan content, prealbumin has been considered a sensitive indicator of protein and/or energy deficiency. In addition, prealbumin diminishes during the acute phase response elicited by either infection or tissue injury. Serum levels of prealbumin were determined in undernourished children with or without associated clinical infection and in their infected or non-infected controls matched for age, sex, race and socioeconomical conditions. Serum levels of prealbumin were significantly lower in undernourished than in control children without overt infections. On the other hand, the concentrations of serum prealbumin diminished significantly and to similar levels both in undernourished and control children with associated clinical infection as compared with those observed in non infected children belonging to the similar nutritional status. A positive correlation was found between prealbumin level and the Z-scores of weight-for-age, height-for-age and weight-for height in children without associated infections, which disappeared in clinically infected patients. Thus, prealbumin is a marker of undernutrition in the absence of infection and could be an earlier and more sensitive indicator of actual undernutrition caused by the metabolic effects of acute phase cytokines, than the anthropometrical measurements used here.

It is known that human hemoglobin contains low levels of N-terminal N-(2-hydroxyethyl)valine. Possible sources of this modified amino acid are exposure to ethylene oxide or other 2-hydroxy-ethylating agents. Although such processes are likely to occur endogenously, the exogenous contribution to the adduct formation is unclear. In order to explore the latter, we have analyzed N-(2-hydroxyethyl)valine in the globin of 49 pregnant women and evaluated the effect of smoking status, area of residence, and glutathione S-transferase M1 genotype on adduct levels. Transplacental transfer of hydroxyethylating agents was also studied by the analysis of umbilical cord hemoglobin. The adduct levels in smokers were significantly higher than those in nonsmokers. The adduct levels in umbilical cord blood globin were quantitatively related to those in maternal blood (maternal:fetal ratio 2.7 in smokers and 2.8 in nonsmokers). In the nonsmokers, there was no statistically significant difference in the adduct level between the urban and rural areas, but the level in suburbia tended to be lower than that in the rural area. In the combined smoker and nonsmoker groups, there was no effect of the glutathione S-transferase M1 genotype on levels of N-(2-hydroxyethyl)valine.