The young binary HD 102077: Orbit, spectral type, kinematics, and moving group membership

The K-type binary star HD 102077 was proposed as a candidate member of the TW Hydrae Association (TWA) which is a young (5-15 Myr) moving group in close proximity (~50 pc) to the solar system. The aim of this work is to verify this hypothesis by different means. We first combine diffraction-limited observations from the ESO NTT 3.5m telescope in SDSS-i' and -z' passbands and ESO 3.6m telescope in H-band with literature data to obtain a new, amended orbit fit, estimate the spectral types of both components, and reanalyse the Hipparcos parallax and proper motion taking the orbital motion into account. Moreover, we use two high-resolution spectra of HD 102077 obtained with the fibre-fed optical echelle spectrograph FEROS at the MPG/ESO 2.2m telescope to determine the radial velocity and the lithium equivalent width of the system. The trajectory of HD 102077 is well constrained and we derive a total system mass of $2.6 \pm 0.8\,$ M$_{\odot}$ and a semi-major axis of $14.9 \pm 1.6\,$AU. From the i'-z' colours we infer an integrated spectral type of K2V, and individual spectral types of K0 +/- 1 and K5 +/- 1. The radial velocity corrected for the orbital motion of the system is $17.6 \pm 2\,$km/s. Even though the parallax determination from the Hipparcos data is not influenced by the orbital motion, the proper motion changes to $\mu_\alpha*\cos(\delta) = -137.84 \pm 1.26\,$ mas/yr and $\mu_\delta = -33.53 \pm 1.45 \,$mas/yr. With the resultant space motion, the probability of HD 102077 being a member of TWA is less than 1%. Furthermore, the lithium equivalent width of $200 \pm 4\,$m\AA $\,$ is consistent with an age between 30 Myr and 120 Myr and thus older than the predicted age of TWA. In conclusion, HD 102077's age, galactic space motion, and position do not fit TWA or any other young moving group

Biofilm formation by Pseudomonas aeruginosa: role of the C4-HSL cell-to-cell signal and inhibition by azithromycin

Objectives: In Pseudomonas aeruginosa, biofilm formation is controlled by a cell-to-cell signalling circuit relying on the secretion of 3-oxo-C12-HSL and C4-HSL. Previous studies suggested that C4-HSL plays no significant role in biofilm formation. However the wild-type PAO1 strain PAO-BI, used as a control in these studies is itself impaired in the production of C4-HSL. We wondered therefore whether the role of C4-HSL in biofilm formation might have been underestimated, and whether azithromycin inhibits biofilm formation by interfering with cell-to-cell signalling. Methods: We used isogenic mutants of wild-type PAO1 strains PAO-BI and PT5 in a static biofilm model. Biofilm formation was quantified using Crystal Violet staining and exopolysaccharide measurements. Results: Wild-type strain PAO-BI, as a result of its reduced C4-HSL secretion, produced 40% less biofilm compared with the wild-type PAO1 strain PT5. Using isogenic mutants of strain PT5 we have shown that whereas a lasI mutant (deficient in 3-oxo-C12-HSL) produced similar amounts of biofilm to the wild-type, a rhlI mutant (deficient in C4-HSL) produced 70% less biofilm. In the latter strain, biofilm formation could be restored by addition of exogenous C4-HSL. Azithromycin, known to reduce the production of both 3-oxo-C12-HSL and C4-HSL, inhibited biofilm formation of wild-type PT5 by 45%. This inhibition could be reversed by the addition of both cell-to-cell signals. Conclusions: Our results indicate that C4-HSL also plays a significant role in biofilm formation. Furthermore, we demonstrate the potential of using cell-to-cell signalling blocking agents such as azithromycin to interfere with biofilm formatio

Spätquartäre paläo-ozeanographische Entwicklung des Nordpolarmeeres und europäischen Nordmeeres anhand von Sauerstoff- und Kohlenstoff-Isotopenverhältnissen der planktischen Foraminifere : Neogloboquadrina pachyderma (sin.)

Oxygen and carbon isotope measurements were carried out on tests of planktic foraminilers N. pachyderma (sin.) from eight sediment cores taken from the eastem Arctic Ocean, the Fram Strait, and the Iceland Sea, in order to reconstruct Arctic Ocean and Norwegian-Greenland Sea circulation patterns and ice covers during the last 130,000 years. ln addition, the influence of ice, temperature and salinity effects on the isotopic signal was quantified. Isotope measurements on foraminifers from sediment surface samples were used to elucidate the ecology of N. pachyderma (sin.). Changes in the oxygen and carbon isotope composition of N. pachyderma (sin.) from sediment surface samples document the horizontal and vertical changes of water mass boundaries controlled by watertemperature and salinity, because N. pachyderma (sin.) shows drastic changes in depth habitats, depending on the water mass properties. It was able to be shown that in the investigated areas a regional and spatial apparent increase of the ice effect occurred. This happened especially du ring the termination 1 by direct advection of meltwaters from nearby continents or during the termination and in interglacials by supply of isotopically light water from rivers. A northwardly proceeding overprint of the "global" ice effect, increasing from the Norwegian-Greenland Sea to the Arctic Ocean, was not able to be demonstrated. By means of a model the influence of temperature and salinity on the global ice volume signal during the last 130.000 years was recorded. In combination with the results of this study, the model was the basis for a reconstruction of the paleoceanographic development of the Arctic Ocean and the Norwegian-Greenland Sea during this time interval. The conception of a relatively thick and permanent sea ice cover in the Nordic Seas during glacial times should be replaced by the model of a seasonally and regionally highly variable ice cover. Only during isotope stage 5e may there have been a local deep water formation in the Fram Strait

Nonparametric longitudinal allele-sharing model

Basically no methods are available for the analysis of quantitative traits in longitudinal genetic epidemiological studies. We introduce a nonparametric factorial design for longitudinal data on independent sib pairs, modelling the phenotypic quadratic differences as the dependent variable. Factors are the number of alleles shared identically by descent (IBD) and the age categories at which the dependent variable is measured, allowing for dependence due to age. To identify a linked marker a rank statistic tests the influence of IBD group on phenotypic quadratic differences. No assumptions are made on normality or variances of the dependent variable. We apply our method to 71 sib pairs from the Framingham Heart Study data provided at the Genetic Analysis Workshop 13. For all 15 available markers on chromosome 17 we analyzed the influence on systolic blood pressure. In addition, different selection strategies to sample from the whole data are discussed

Alpha radiation from polymetallic nodules and potential health risks from deep-sea mining

In search for critical elements, polymetallic nodules at the deep abyssal seafloor are targeted for mining operations. Nodules efficiently scavenge and retain several naturally occurring uranium-series radioisotopes, which predominantly emit alpha radiation during decay. Here, we present new data on the activity concentrations of thorium-230, radium-226, and protactinium-231, as well as on the release of radon-222 in and from nodules from the NE Pacific Ocean. In line with abundantly published data from historic studies, we demonstrate that the activity concentrations for several alpha emitters are often higher than 5 Bq g−1 at the surface of the nodules. These observed values can exceed current exemption levels by up to a factor of 1000, and even entire nodules commonly exceed these limits. Exemption levels are in place for naturally occurring radioactive materials (NORM) such as ores and slags, to protect the public and to ensure occupational health and radiation safety. In this context, we discuss three ways of radiation exposure from nodules, including the inhalation or ingestion of nodule fines, the inhalation of radon gas in enclosed spaces and the potential concentration of some radioisotopes during nodule processing. Seen in this light, inappropriate handling of polymetallic nodules poses serious health risks

Autoinducer production and quorum-sensing dependent phenotypes of Pseudomonas aeruginosa vary according to isolation site during colonization of intubated patients

<p>Abstract</p> <p>Background</p> <p><it>Pseudomonas aeruginosa </it>frequently colonizes and is responsible for severe ventilator-associated pneumonia in intubated patients. A quorum-sensing (QS) circuit, depending on the production of the two QS-signaling molecules (autoinducers, AIs) 3-oxo-C₁₂-HSL and C₄-HSL, regulates the production by <it>P. aeruginosa </it>of several virulence factors and is required for biofilm formation. Therefore QS-inhibition has been suggested as a new target for preventive and/or therapeutic strategies. However the precise role of QS during colonization and subsequent infections of intubated patients remains unclear.</p> <p>Results</p> <p>We wondered whether QS is active during colonization of intubated patients, and whether <it>P. aeruginosa </it>isolates growing inside the biofilm covering the intubation devices and those resident in the lungs of colonized patients differ in their QS-dependent phenotypes. We collected the intubation devices of eight patients colonized by <it>P. aeruginosa</it>. We detected 3-oxo-C₁₂-HSL on eight, and C₄-HSL on six of these devices. In three of these patients we also obtained <it>P. aeruginosa </it>isolates from tracheal aspirates at the time of extubation (n = 18), as well as isolates from the intubation devices (n = 25). We genotyped these isolates, quantified their AIs production, and determined three QS-dependent phenotypes (adherence capacity, biofilm and elastase production). The production of 3-oxo-C₁₂-HSL was consistently increased for isolates from the intubation devices, whereas the production of C₄-HSL was significantly higher for isolates from tracheal aspirates. Isolates from tracheal aspirates produced significantly higher amounts of elastase but less biofilm, and had a marginally reduced adhesion capacity than isolates from the intubation devices. Levels of 3-oxo-C₁₂-HSL and elastase production correlated statistically for tracheal intubation isolates, whereas levels of 3-oxo-C₁₂-HSL production and adhesion ability, as well as biofilm production, correlated weakly amongst intubation device isolates.</p> <p>Conclusion</p> <p>Our findings demonstrate that autoinducers are produced during the colonization of intubated patients by <it>P. aeruginosa</it>. The microenvironment, in which <it>P. aeruginosa </it>grows, may select for bacteria with different capacities to produce autoinducers and certain QS-dependent phenotypes. QS-inhibition might therefore affect differently isolates growing inside the biofilm covering intubation devices and those resident in the lungs.</p

Activation of the Nrf2-ARE Pathway in Hepatocytes Protects Against Steatosis in Nutritionally Induced Non-alcoholic Steatohepatitis in Mice

Oxidative stress is implicated in the development of non-alcoholic steatohepatitis (NASH). The Nrf2-antioxidant response element pathway protects cells from oxidative stress. Studies have shown that global Nrf2 deficiency hastens the progression of NASH. The purpose of this study was to determine whether long-term hepatocyte-specific activation of Nrf2 mitigates NASH progression. Transgenic mice expressing a constitutively active Nrf2 construct in hepatocytes (AlbCre+/caNrf2+) and littermate controls were generated. These mice were fed standard or methionine-choline-deficient (MCD) diet, a diet used to induce NASH development in rodents. After 28 days of MCD dietary feeding, mice developed significant increases in steatosis, inflammation, oxidative stress, and HSC activation compared with those mice on standard diet. AlbCre+/caNrf2+ animals had significantly decreased serum transaminases and reduced steatosis when compared with the AlbCre+/caNrf2− animals. This significant reduction in steatosis was associated with increased expression of genes involved in triglyceride export (MTTP) and β-oxidation (CPT2). However, there were no differences in the increased oxidative stress, inflammation, and HSC activation from MCD diet administration between the AlbCre+/caNrf2− and AlbCre+/caNrf2+ animals. We conclude that hepatocyte-specific activation of Nrf2-mediated gene expression decreased hepatocellular damage and steatosis in a dietary model of NASH. However, hepatocyte-specific induction of Nrf2-mediated gene expression alone is insufficient to mitigate inflammation, oxidative stress, and HSC activation in this nutritional NASH mode

University entrance qualification at vocational schools from students\u27 perspectives

Berufskollegs bieten wie Berufsfachschulen, Fachoberschulen und berufliche Gymnasien/Fachgymnasien vielfältige Möglichkeiten der berufsbezogenen Bildung. Wie diese Qualifikationsphase von jungen Erwachsenen wahrgenommen wird und welche Bedeutung das Berufskolleg für den Übergang hat, wird in diesem Beitrag anhand erster Ergebnisse einer empirischen Längsschnittstudie dokumentiert. Mittels narrativer Interviews werden nicht nur die biografische Bedeutung des Berufskollegs und die für den Übergang relevanten Entwürfe rekonstruiert, sondern auch die damit im Zusammenhang stehenden habituellen Orientierungen der jungen Erwachsenen. Eine Musterbildung zur mehrfachen Bedeutung des Berufskollegs stellt die ersten Ergebnisse der empirischen Studie zur Diskussion. (DIPF/Orig.)The Berufskolleg, the vocational school type in North Rhine-Westphalia, offers versatile opportunities of vocational education. How young adults perceive this period of qualifycation and what significance the Berufskolleg has for the transition, will be discussed in this article based on a longitudinal study. Using narrative interviews, not only the biographical significance of the Berufskolleg and the concepts, which are relevant for the process of vocational orientation, are reconstructed, but also the related habitual orientations of young adults. (DIPF/Orig.

Component resolution reveals additional major allergens in patients with honeybee venom allergy

BackgroundDetection of IgE to recombinant Hymenoptera venom allergens has been suggested to improve the diagnostic precision in Hymenoptera venom allergy. However, the frequency of sensitization to the only available recombinant honeybee venom (HBV) allergen, rApi m 1, in patients with HBV allergy is limited, suggesting that additional HBV allergens might be of relevance.ObjectiveWe performed an analysis of sensitization profiles of patients with HBV allergy to a panel of HBV allergens.MethodsDiagnosis of HBV allergy (n = 144) was based on history, skin test results, and allergen-specific IgE levels to HBV. IgE reactivity to 6 HBV allergens devoid of cross-reactive carbohydrate determinants (CCD) was analyzed by ImmunoCAP.ResultsIgE reactivity to rApi m 1, rApi m 2, rApi m 3, nApi m 4, rApi m 5, and rApi m 10 was detected in 72.2%, 47.9%, 50.0%, 22.9%, 58.3%, and 61.8% of the patients with HBV allergy, respectively. Positive results to at least 1 HBV allergen were detected in 94.4%. IgE reactivity to Api m 3, Api m 10, or both was detected in 68.0% and represented the only HBV allergen–specific IgE in 5% of the patients. Limited inhibition of IgE binding by therapeutic HBV and limited induction of Api m 3– and Api m 10–specific IgG4 in patients obtaining immunotherapy supports recent reports on the underrepresentation of these allergens in therapeutic HBV preparations.ConclusionAnalysis of a panel of CCD-free HBV allergens improved diagnostic sensitivity compared with use of rApi m 1 alone, identified additional major allergens, and revealed sensitizations to allergens that have been reported to be absent or underrepresented in therapeutic HBV preparations