73 research outputs found
Arabidopsis thaliana leaves with altered chloroplast numbers and chloroplast movement exhibit impaired adjustments to both low and high light
The effects of chloroplast number and size on the capacity for blue light-dependent chloroplast movement, the ability to increase light absorption under low light, and the susceptibility to photoinhibition were investigated in Arabidopsis thaliana. Leaves of wild-type and chloroplast number mutants with mean chloroplast numbers ranging from 120 to two per mesophyll cell were analysed. Chloroplast movement was monitored as changes in light transmission through the leaves. Light transmission was used as an indicator of the ability of leaves to optimize light absorption. The ability of leaves to deal with 3 h of high light stress at 10 °C and their capacity to recover in low light was determined by measuring photochemical efficiencies of PSII using chlorophyll a fluorescence. Chloroplast movement was comparable in leaves ranging in chloroplast numbers from 120 to 30 per mesophyll cell: the final light transmission levels after exposure to 0.1 (accumulation response) and 100 ÎŒmol photons mâ2 sâ1 (avoidance response) were indistinguishable, the chloroplasts responded quickly to small increases in light intensity and the kinetics of movement were similar. However, when chloroplast numbers per mesophyll cell decreased to 18 or below, the accumulation response was significantly reduced. The avoidance response was only impaired in mutants with nine or fewer chloroplasts, both in terms of final transmission levels and the speed of movement. Only mutants lacking both blue light receptors (phot1/phot2) or those with drastically reduced chloroplast numbers and severely impacted avoidance responses showed a reduced ability to recover from high light stress
Transport von Silbernanopartikeln in natĂŒrlich gelagerten BodensĂ€ulen
Die Anzahl der wissenschaftlichen Untersuchungen zum Verbleib von Silbernanopartikeln (Ag-NP) in Böden hat in den letzten Jahren zugenommen. Da die publizierten Ergebnisse darauf hinweisen, dass sie stark durch die gewĂ€hlten Versuchs- und Randbedingungen beeinflusst werden, bleibt die Bewertung der MobilitĂ€t von Silbernanopartikeln in Böden schwierig. Daher sollte der Transport und Verbleib der Ag-NP in dieser Untersuchung unter naturnahe Bedingung, aber mit kontrollierten Rand- und Anfangsbedingungen bestimmt werden. Dazu wurden an zwei Standorten (Sand, Schluff) jeweils acht ungestörte BodensĂ€ulen (Ă 10,2 cm Höhe 16 cm) genommen und in einer SĂ€ulenversuchsanlage (SCS, Fa. emc GmbH) untersucht. Drei SĂ€ulen dienten jeweils als Parallelen wĂ€hrend eine SĂ€ule als Kontrolle ohne Zugabe von NP untersucht wurde. FĂŒr beide Bodenarten erfolgten Versuche mit gesĂ€ttigtem und ungesĂ€ttigtem Fluss. Zur Nachverfolgung des Wasserflusses durch die SĂ€ulen wurde dem Beregnungswasser D2O als Tracer zugesetzt. Die Silbergesamtgehalte im Perkolat wurde nach HNO3-Aufschluss und mit ICP-OES/MS analysiert. Die Messung der gelösten Silberfraktion erfolgte nach Ultrazentrifugation mit ICP-MS. Die GröĂenverteilung von natĂŒrlichen Bodenkolloiden und Ag-NP wurde mit Dynamic Light Scattering (Malvern NanoZS) gemessen. Die Ergebnisse bestĂ€tigen den Einfluss der Versuchsbedingungen, zeigen aber auch die Bedeutung der Bodenstruktur auf die MobilitĂ€t der Ag-NP. Die VariabilitĂ€t zwischen den Parallelproben ist sehr groĂ und ĂŒberschattet mögliche Unterschiede zwischen den Bodenarten. Bevorzugte FlieĂwege sind wohl die Regel, die frĂŒhen DurchbrĂŒche von D2O und Ag-NP bestĂ€tigt den prĂ€ferentiellen Transport von Wasser und Partikeln. Mit Hilfe eines nachtrĂ€glich durch die SĂ€ule perkolierten Farbstoffes (Brillant Blue) wurde Randfluss ausgeschlossen. Unter ungesĂ€ttigten Bedingungen wird ein deutlich gröĂerer Teil der Ag-NP im Boden zurĂŒckgehalten als unter gesĂ€ttigten FlieĂbedingungen. Daher wird angenommen, dass die Bodenluft fĂŒr die Retention der Partikel im Boden wichtig ist
Functional leaf traits of understory species: strategies to different disturbance severities
Effect of rosuvastatin on outcomes in chronic haemodialysis patients â design and rationale of the AURORA study
BACKGROUND: Patients with end-stage renal disease (ESRD) are at high risk of cardiovascular events. Multiple risk factors for atherosclerosis are present in ESRD and may contribute to the increased risk of cardiovascular mortality in this population. In contrast to patients with normal renal function, the benefits of modifying lipid levels on cardiovascular outcomes in patients with ESRD on haemodialysis have yet to be confirmed in large prospective randomised trials. A study to evaluate the Use of Rosuvastatin in subjects On Regular haemodialysis: an Assessment of survival and cardiovascular events (AURORA) will be the first large-scale international trial to assess the effects of statin therapy on cardiovascular morbidity and mortality in ESRD patients on chronic haemodialysis. METHODS: More than 2,750 ESRD patients who have been receiving chronic haemodialysis treatment for at least 3 months have been randomised (1:1), irrespective of baseline lipid levels, to treatment with rosuvastatin 10 mg or placebo. The primary study endpoint is the time to a major cardiovascular event (first occurrence of cardiovascular death, non-fatal myocardial infarction or non-fatal stroke). Secondary endpoints include all-cause mortality, major cardiovascular event-free survival time, time to cardiovascular death, time to non-cardiovascular death, cardiovascular interventions, tolerability of treatment and health economic costs per life-year saved. Study medication will be given until 620 subjects have experienced a major cardiovascular event. CONCLUSION: Our hypothesis is that results from AURORA will establish the clinical efficacy and tolerability of rosuvastatin in patients with ESRD receiving chronic haemodialysis and guide the optimal management of this expanding population
International consensus on the most useful physical examination tests used by physiotherapists for patients with headache: A Delphi study
Background: A wide range of physical tests have been published for use in the assessment of musculoskeletal dysfunction in patients with headache. Which tests are used depends on a physiotherapist's clinical and scientific background as there is little guidance on the most clinically useful tests. Objectives: To identify which physical examination tests international experts in physiotherapy consider the most clinically useful for the assessment of patients with headache. Design/methods: Delphi survey with pre-specified procedures based on a systematic search of the literature for physical examination tests proposed for the assessment of musculoskeletal dysfunction in patients with headache. Results: Seventeen experts completed all three rounds of the survey. Fifteen tests were included in round one with eleven additional tests suggested by the experts. Finally eleven physical examination tests were considered clinically useful: manual joint palpation, the cranio-cervical flexion test, the cervical flexion-rotation test, active range of cervical movement, head forward position, trigger point palpation, muscle tests of the shoulder girdle, passive physiological intervertebral movements, reproduction and resolution of headache symptoms, screening of the thoracic spine, and combined movement tests. Conclusions: Eleven tests are suggested as a minimum standard for the physical examination of musculoskeletal dysfunctions in patients with headache
Risk profiles and one-year outcomes of patients with newly diagnosed atrial fibrillation in India: Insights from the GARFIELD-AF Registry.
BACKGROUND: The Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF) is an ongoing prospective noninterventional registry, which is providing important information on the baseline characteristics, treatment patterns, and 1-year outcomes in patients with newly diagnosed non-valvular atrial fibrillation (NVAF). This report describes data from Indian patients recruited in this registry. METHODS AND RESULTS: A total of 52,014 patients with newly diagnosed AF were enrolled globally; of these, 1388 patients were recruited from 26 sites within India (2012-2016). In India, the mean age was 65.8 years at diagnosis of NVAF. Hypertension was the most prevalent risk factor for AF, present in 68.5% of patients from India and in 76.3% of patients globally (P < 0.001). Diabetes and coronary artery disease (CAD) were prevalent in 36.2% and 28.1% of patients as compared with global prevalence of 22.2% and 21.6%, respectively (P < 0.001 for both). Antiplatelet therapy was the most common antithrombotic treatment in India. With increasing stroke risk, however, patients were more likely to receive oral anticoagulant therapy [mainly vitamin K antagonist (VKA)], but average international normalized ratio (INR) was lower among Indian patients [median INR value 1.6 (interquartile range {IQR}: 1.3-2.3) versus 2.3 (IQR 1.8-2.8) (P < 0.001)]. Compared with other countries, patients from India had markedly higher rates of all-cause mortality [7.68 per 100 person-years (95% confidence interval 6.32-9.35) vs 4.34 (4.16-4.53), P < 0.0001], while rates of stroke/systemic embolism and major bleeding were lower after 1 year of follow-up. CONCLUSION: Compared to previously published registries from India, the GARFIELD-AF registry describes clinical profiles and outcomes in Indian patients with AF of a different etiology. The registry data show that compared to the rest of the world, Indian AF patients are younger in age and have more diabetes and CAD. Patients with a higher stroke risk are more likely to receive anticoagulation therapy with VKA but are underdosed compared with the global average in the GARFIELD-AF. CLINICAL TRIAL REGISTRATION-URL: http://www.clinicaltrials.gov. Unique identifier: NCT01090362
Electron-microscopical study of the formation of iron carbide phases after high- fluence carbon ion implantation into iron at low temperature
Electron-microscopical study of the formation of iron carbide phases after high- fluence carbon ion implantation into iron at low temperature / C. Hammerl, A. Königer and B. Rauschenbach. - In: Journal of materials research. 13. 1998. S. 2614-262
Electronmicroscopical Study of the Formation of Iron Carbide Phases After High-fluence Carbon Ion Implantation into Iron at Low Temperatures
Carbon ions were implanted with energies between 50 and 150 keV into thin iron layers at temperatures of â10 °C and â70 °C. Formation of iron carbide phases was studied as a function of fluence, which was varied from 1.2 Ă 1017 C+-ions/cm2 up to 1.4 Ă 1018 C+-ions/cm2. The sequence of phase transformation during subsequent annealing to temperatures of up to 450 °C was also investigated. Detailed analysis of structure and morphology was done by cross-sectional transmission electron microscopy and electron diffraction experiments. The existence of metastable iron carbide phases, Ξ-Fe3C, Χ-Fe5C2, η-Fe2C, and also the amorphous phase Fe(C), after high-fluence carbon ion implantation and the transformation of the formed metastable phases by subsequent annealing into the Ξ-Fe3C phase are demonstrated
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