227 research outputs found

    Development of the 33-, 23- and 16-kDa polypeptides of the photosynthetic oxygen-evolving system during greening

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    AbstractThe accumulation of the 33-, 23- and 16-kDa polypeptides of the oxygen-evolving complex has been compared with the development of oxygen evolution activity during greening. Both the 33- and 23-kDa proteins are present in etioplast membranes whereas the 16-kDa species is detectable only in trace amounts. The accumulation of the 3 polypeptides' greening is asynchronous. Only the 16-kDa polypeptide is formed in concert with the appearance of oxygen evolving activity.Thylakoid developmentPhotosynthetic oxygen evolution33-kDa protein23-kDa protein16-kDa proteinWestern blottin

    Air pollution episodes in Stockholm regional background air due to sources in Europe and their effects on human population

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    Using air quality measurements, we categorized air pollution according to source sectors in a rural background environment in southern Sweden based on hourly air-mass backward trajectories during 1997-2010. Concentrations of fine (PM2.5) and sum of fine and coarse particulate matter (PM10), accumulation mode particle number, black carbon and surface ozone were 4.0, 3.9, 4.5, 6.8 and 1.3 times higher, respectively, in air masses from the southeast as compared with those in air masses from the cleanest sector in the northwest, consistent with air-mass transport over areas with relatively high emissions of primary particulate matter (PM) and secondary PM precursors. The highest ultrafine particle numbers were associated with clean air from the northwest. We estimate that almost 7.8% and 0.6% higher premature human mortality is caused by PM2.5 and ozone exposure, respectively, when air originates from the southeast as compared with that when air originates from the northwest. Reductions of emissions in eastern Europe would reduce the highest air pollution concentrations and associated health risks. However, since air masses from the southwest are more frequent, emissions in the western part of Europe are more important for annual mean premature mortality

    Heavy vehicle traffic is related to wheeze among schoolchildren: a population-based study in an area with low traffic flows

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    <p>Abstract</p> <p>Background</p> <p>An association between traffic air pollution and respiratory symptoms among children has been reported. However, the effects of traffic air pollution on asthma and wheeze have been very sparsely studied in areas with low traffic intensity in cold climate with poor dispersion. We evaluated the impact of vehicle traffic on childhood asthma and wheeze by objective exposure assessment.</p> <p>Methods</p> <p>As a part of the Obstructive Lung Disease in Northern Sweden (OLIN) studies, a questionnaire was sent to the families of all children attending first or second grade in Luleå (72,000 inhabitants) in Northern Sweden in 2006. The age of the children was 7-8 years and the participation rate was 98% (n = 1357). Skin prick tests were performed in 1224 (89%) children. The home addresses were given geographical coordinates and traffic counts were obtained from the local traffic authorities. A proximity model of average daily traffic and average daily heavy vehicle traffic within 200 meters from each participant's home address was used. The associations between traffic exposure and asthma and wheeze, respectively, were analysed in an adjusted multiple logistic regression model.</p> <p>Results</p> <p>Exposure to high traffic flows was uncommon in the study area; only 15% of the children lived within 200 meters from a road with a traffic flow of ≥8000 vehicles per day. Living closer than 200 meters from a road with ≥500 heavy vehicles daily was associated with current wheeze, odds ratio 1.7 (confidence interval 1.0-2.7). A dose-response relation was indicated. An increased risk of asthma was also seen, however not significant, odds ratio 1.5 (confidence interval 0.8-2.9). Stratified analyses revealed that the effect of traffic exposure was restricted to the non-sensitized phenotype of asthma and wheeze. The agreement between self-reported traffic exposure and objective measurements of exposure was moderate.</p> <p>Conclusions</p> <p>This study showed that already at low levels of exposure, vehicle traffic is related to an increased risk of wheeze among children. Thus, the global burden of traffic air pollution may be underestimated.</p

    Isolation of a highly active PSII-LHCII supercomplex from thylakoid membranes by a direct method

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    Abstract We have developed a simple and novel method to isolate a highly pure and active photosystem (PS) II complex, directly from thylakoid membranes. This complex is a discrete particle and contains all the proteins of the oxygen evolving complex and a set of chlorophyll a/b binding proteins. The intactness of both the donor side and the acceptor side has resulted in a very high oxygen evolution activity and therefore offers a superior experimental system to that of PSII enriched membrane fragments in which there is heterogeneity in activities and biochemical composition. z 1999 Federation of European Biochemical Societies

    Rev. Mineral. Geochem. 69. 61-120

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    Improving our understanding of magma plumbing and storage remains one of the major challenges for petrologists and volcanologists today. This is especially true for explosive volcanoes, where constraints on magma plumbing are essential for predicting dynamic changes in future activity and thus for hazard mitigation. This study aims to investigate the magma plumbing system at Anak Krakatau; the post-collapse cone situated on the rim of the 1883 Krakatau caldera. Since 1927, Anak Krakatau has been highly active, growing at a rate of ∼8 cm/week. The methods employed are a.) clinopyroxene-melt thermo-barometr

    Repeated Measurements of Cardiac Biomarkers in Atrial Fibrillation and Validation of the ABC Stroke Score Over Time

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    Background--Cardiac biomarkers are independent risk markers in atrial fibrillation, and the novel biomarker-based ABC stroke score (age, biomarkers, and clinical history of prior stroke) was recently shown to improve the prediction of stroke risk in patients with atrial fibrillation. Our aim was to investigate the short-term variability of the cardiac biomarkers and evaluate whether the ABC stroke risk score provides a stable short- term risk estimate. Methods and Results--According to the study protocol, samples were obtained at entry and also at 2 months in 4796 patients with atrial fibrillation followed for a median of 1.8 years in the ARISTOTLE (Apixaban for Reduction in Stroke and Other Thromboembolic Events in Atrial Fibrillation) trial. Cardiac troponin I, cardiac troponin T, and N-terminal pro-B-type natriuretic peptide were measured with high-sensitivity immunoassays. Associations with outcomes were evaluated by Cox regression. C indices and calibration plots were used to evaluate the ABC stroke score at 2 months. The average changes in biomarker levels during 2 months were small ( median change cardiac troponin T +2.8%, troponin I +2.0%, and N-terminal pro-B-type natriuretic peptide +13.5%) and within-subject correlation was high ( all >= 0.82). Repeated measurement of cardiac biomarkers provided some incremental prognostic value for mortality but not for stroke when combined with clinical risk factors and baseline levels of the biomarkers. Based on 8702 person-years of follow-up and 96 stroke/systemic embolic events, the ABC stroke score at 2 months achieved a similar C index of 0.70 (95% CI, 0.65-0.76) as compared with 0.70 (95% CI, 0.65-0.75) at baseline. The ABC stroke score remained well calibrated using predefined risk classes. Conclusions--In patients with stable atrial fibrillation, the variability of the cardiac biomarkers and the biomarker- based ABC stroke score during 2 months are small. The prognostic information by the ABC stroke score remains consistent and well calibrated with similar good predictive performance if patients are retested after 2 months. Clinical Trial Registration --URL: http://www.clinicaltrials.gov. Unique identifier: NCT00412984.Peer reviewe

    Cognitive outcome two years after frontal lobe resection for epilepsy – A prospective longitudinal study

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    AbstractPurposeTo investigate cognitive outcomes after frontal lobe resection (FLR) for epilepsy in a consecutive single centre series.MethodsNeuropsychological examinations were performed prior to and two years (mean test interval 2.5 years) after surgery in 30 consecutive patients who underwent FLR. Cognitive outcome was evaluated with particular consideration to the site of surgery (lateral, premotor/SMA [supplementary motor area], mesial/orbital). Cognitive domains assessed were speed, language, memory, attention, executive functions and intelligence. 25 healthy controls were assessed at corresponding time points (mean test interval 3.0 years). Analyses were made both at group and individual levels.ResultsAt baseline the patients performed below controls in variables depending on speed, executive functions, global and verbal intelligence. Two years after surgery, the analyses at the subgroup level indicated that the lateral resection group had less improvement than the controls in global intelligence, FSIQ (p=.037). However, at the individual level, the majority of the change scores (74–100%) were classified as within the normal range for all but one variable. The exception was the variable “Comprehension” (measuring verbal reasoning ability) with reliable declines in 44% (8/18) of the patients. This pattern of decline was observed in the lateral (4/7 patients) and premotor/SMA (4/7 patients) resection groups. Seizure outcome and side of surgery did not influence these results.ConclusionThe main finding was cognitive stability at group level two years after FLR. A reliable decline in verbal reasoning ability was rather common at an individual level, but only in the lateral and premotor/SMA resection groups. The lateral resection group also had less improvement than the controls in global intelligence
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