Determination of the electron's solvation site on D₂O/Cu(111) using Xe overlayers and femtosecond photoelectron spectroscopy

We investigate the binding site of solvated electrons in amorphous D2O clusters and D2O wetting layers adsorbed on Cu(111) by means of two-photon photoelectron (2PPE) spectroscopy. On the basis of different interactions of bulk- or surface-bound solvated electrons with rare gas atoms, titration experiments using Xe overlayers reveal the location of the electron solvation sites. In the case of flat clusters with a height of 2-4 bilayers adsorbed on Cu(111), solvated electrons are found to reside at the ice - vacuum interface, whereas a bulk character is determined for solvated electrons in wetting layers. Furthermore, time-resolved experiments are performed to determine the origin of the transition between these different solvation sites with increasing D2O coverage. We employ an empirical model calculation to analyse the rate of electron transfer back to the substrate and the energetic stabilization of the solvated electrons, which allows further insight into the binding site for clusters. We find that the solvated electrons reside at the edges of the clusters. Therefore, we attribute the transition from surface- to bulk-solvation to the coalescence of the clusters to a closed ice film occurring at a nominal coverage of 2-3 BL, while the distance of the binding sites to the metal-ice interface is maintained

Higher-order mean-field theory of chiral waveguide QED

Waveguide QED with cold atoms provides a potent platform for the study of non-equilibrium, many-body, and open-system quantum dynamics. Even with weak coupling and strong photon loss, the collective enhancement of light-atom interactions leads to strong correlations of photons arising in transmission, as shown in recent experiments. Here we apply an improved mean-field theory based on higher-order cumulant expansions to describe the experimentally relevant, but theoretically elusive, regime of weak coupling and strong driving of large ensembles. We determine the transmitted power, squeezing spectra and the degree of second-order coherence, and systematically check the convergence of the results by comparing expansions that truncate cumulants of few-particle correlations at increasing order. This reveals the important role of many-body and long-range correlations between atoms in steady state. Our approach allows to quantify the trade-off between anti-bunching and output power in previously inaccessible parameter regimes. Calculated squeezing spectra show good agreement with measured data, as we present here.Comment: 16+9 pages, 9+2 figure

Recognition and processing of a new repertoire of DNA substrates by human 3-methyladenine DNA glycosylase (AAG)

The human 3-methyladenine DNA glycosylase (AAG) recognizes and excises a broad range of purines damaged by alkylation and oxidative damage, including 3-methyladenine, 7-methylguanine, hypoxanthine (Hx), and 1,N[superscript 6]-ethenoadenine (εA). The crystal structures of AAG bound to εA have provided insights into the structural basis for substrate recognition, base excision, and exclusion of normal purines and pyrimidines from its substrate recognition pocket. In this study, we explore the substrate specificity of full-length and truncated Δ80AAG on a library of oligonucleotides containing structurally diverse base modifications. Substrate binding and base excision kinetics of AAG with 13 damaged oligonucleotides were examined. We found that AAG bound to a wide variety of purine and pyrimidine lesions but excised only a few of them. Single-turnover excision kinetics showed that in addition to the well-known εA and Hx substrates, 1-methylguanine (m1G) was also excised efficiently by AAG. Thus, along with εA and ethanoadenine (EA), m1G is another substrate that is shared between AAG and the direct repair protein AlkB. In addition, we found that both the full-length and truncated AAG excised 1,N[superscript 2]-ethenoguanine (1,N[superscript 2]-εG), albeit weakly, from duplex DNA. Uracil was excised from both single- and double-stranded DNA, but only by full-length AAG, indicating that the N-terminus of AAG may influence glycosylase activity for some substrates. Although AAG has been primarily shown to act on double-stranded DNA, AAG excised both εA and Hx from single-stranded DNA, suggesting the possible significance of repair of these frequent lesions in single-stranded DNA transiently generated during replication and transcription.United States. National Institutes of Health (grant ES05355)United States. National Institutes of Health (grant CA75576)United States. National Institutes of Health (grant CA55042)United States. National Institutes of Health (grant ES02109)United States. National Institutes of Health (grant T32-ES007020)United States. National Institutes of Health (grant CA80024)United States. National Institutes of Health (grant CA26731

Predicting major bleeding in patients with noncardioembolic stroke on antiplatelets

Objective: To develop and externally validate a prediction model for major bleeding in patients with a TIA or ischemic stroke on antiplatelet agents. Methods: We combined individual patient data from 6 randomized clinical trials (CAPRIE, ESPS-2, MATCH, CHARISMA, ESPRIT, and PRoFESS) investigating antiplatelet therapy after TIA or ischemic stroke. Cox regression analyses stratified by trial were performed to study the association between predictors and major bleeding. A risk prediction model was derived and validated in the PERFORM trial. Performance was assessed with the c statistic and calibration plots. Results: Major bleeding occurred in 1,530 of the 43,112 patients during 94,833 person-years of follow-up. The observed 3-year risk of major bleeding was 4.6% (95% confidence interval [CI] 4.4%–4.9%). Predictors were male sex, smoking, type of antiplatelet agents (aspirin-clopidogrel), outcome on modified Rankin Scale ≥3, prior stroke, high blood pressure, lower body mass index, elderly, Asian ethnicity, and diabetes (S2TOP-BLEED). The S2TOP-BLEED score had a c statistic of 0.63 (95% CI 0.60–0.64) and showed good calibration in the development data. Major bleeding risk ranged from 2% in patients aged 45–54 years without additional risk factors to more than 10% in patients aged 75–84 years with multiple risk factors. In external validation, the model had a c statistic of 0.61 (95% CI 0.59–0.63) and slightly underestimated major bleeding risk. Conclusions: The S2TOP-BLEED score can be used to estimate 3-year major bleeding risk in patients with a TIA or ischemic stroke who use antiplatelet agents, based on readily available characteristics. The discriminatory performance may be improved by identifying stronger predictors of major bleeding

Study of maize response on drip irrigation basing on long-term field experiment

W latach 2000–2008 przeprowadzono w Stacji Badawczej Wydziału Rolniczego UTP w Mochełku pod Bydgoszczą dwuczynnikowe doświadczenie z nawadnianiem kukurydzy odmiany ‘Cedro’ o liczbie FAO 230 na glebie płowej typowej, zaliczanej do klasy IVa. W badaniu zastosowano dwa poziomy nawożenia azotem (90 i 150 kg.ha-1). Wody dostarczano roślinom za pomocą linii kroplującej z wtopionymi emiterami firmy NAAN, rozłożoną wzdłuż rzędów roślin. Średnio, w latach badań, zadysponowano 112 mm wody (28 mm w czerwcu, 49 mm w lipcu, 28 mm w sierpniu i 7 mm we wrześniu), a w poszczególnych sezonach ilość dodatkowej wody wahała się od 25 mm (w roku 2007) do 215 mm w 2008. Zastosowanie nawadniania spowodowało wzrost plonu suchego ziarna kukurydzy z poziomu 5,62 t.ha-1 do 8,53 t.ha-1, a więc o 2,91 t.ha-1(52%). Wielkość przyrostu plonu w latach badań wahała się od 0,46 t.ha-1 w roku 2000, poprzez 0,60 (w chłodnym 2004) do 8,47 (w 2006 z bardzo gorącym i suchym lipcem) i 6,26 w 2008 r. (z małymi opadami V–VII). Uzyskane w doświadczeniu efekty stosowania uzupełniającego niedobory opadów nawadniania zależały w największym stopniu od sumy opadów atmosferycznych lipca, im te opady mniejsze, tym przyrosty plonu ziarna większe. Drugi czynnik – nawozowy – także spowodował istotne zwiększenie produkcji ziarna, ale w porównaniu do nawadniania, znacznie mniejsze, bo wynoszące zaledwie 0,25 t.ha-1. Czynniki doświadczenia niejednakowo zróżnicowały wybrane elementy plonu. Zastosowanie nawadniania korzystnie wpłynęło na podniesienie udziału kolb w plonie ogólnym, udział ziarna w kolbie i dorodność ziarna, a nieznacznie obniżyło zawartość białka. Zwiększona dawka azotu wyraźnie podniosła MTZ oraz niewiele zwiększyła ilość białka. Pozostałe cechy plonu, w tym wilgotność ziarna podczas zbioru, nie zostały zróżnicowane czynnikami doświadczenia.The paper presents results of a field experiment with maize varietas ‘Cedro’ (FAO230) irrigated on a light soil, carried out in years 2000-2008 in Mochełek (near Bydgoszcz. A combination of 90 and 150 kg of nitrogen per hectar was applied. Water was supplied by a drip irrigation system using the NAAN emitters. The layout of drip laterals placed in beetwen plants’ rows provided a moisture to the soil in a root zone. In the years of the study an average dose of water of 112 mm was used for irrigation (28 mm in June, 49 mm in July, 28 mm in August and 7 mm in September), but in separate seasons the dose varried from 25 mm (year 2007) to 215 mm (year 2008). Irrigation have increased the yield of corn from 5,62 t.ha-1 to 8,53 t.ha-1, which is 2,91 t.ha-1(52%). The increase of the yield of corn in separate years varied from 0,46 t.ha-1 (year 2000) and 0,60 t.ha-1 (in a cold year 2004) to 8,47 t.ha-1(in year 2006 when the art temperature in July was very high) and 6,26 t.ha-1(in year 2008 when was a rainfall shortage in months V-VII). The results of the studies have shown that the effects of the suplementary irrigation have subordinated from the rainfall in July. The lowest was the rainfall in the month , the highest was the corn yield increase. Also the nitrogen fertilization have influenced positively the effects of the yield, but in the comparison with the irrigation effects, the increase was less and equalled of 0,25 t.ha-1. Both elements, water and nitrogen have influenced the constituents of yield but in a different way. Irrigation have increased the quota of corncobs in the total yield, the quota of corn in a cob and quality of corn, but slightly decreased a quantity of protein. The highest dose of nitrogen (150 kg.ha-1) has significantly increased the DM grain of maize and has slightly increased quantity of protein. Other constituents of yield i.e. a moisture of corn haven been influenced by the elements applied

Comparison of chosen meteorological elements measured in the centre of Bydgoszcz and its surroundings

The aim of the study was a comparison of selected meteorological elements, measured with automatic weather stations in two localizations: centre of an urban area (Bydgoszcz) and in an open surroundings (Mochełek). The distance between the both places was about 20 km in a line. Results of the investigation confi rmed the presence of a heat urban island in Bydgoszcz. The urban area was distinguished by higher (of 1.3°C) air temperature higher saturation defi cit (1.1 hPa), whereas lower mean monthly relative humidity (8.3%), wind speed (2.5 m·s–2), monthly total precipitation (7.8 mm) and global solar radiation (32%), comparing to the rural location. The distinctions were not equal in particular monthly periods and in particular cases of meteorological elements. Global solar radiation, air temperature, relative humidity and wind speed differ most in the winter time while saturation defi cit and precipitation vary in summer