38 research outputs found
Isolierung und Charakterisierung ectomesenchymaler Progenitorzellen aus der juvenilen murinen Cornea
No full textIn der vorliegenden Studie konnte die erfolgreiche Isolierung ectomesenchymaler Zellen aus dem cornealen Limbus juveniler Mäuse dargestellt werden. Die hier etablierten Zellen sind mit stromalen Keratozyten verwandt und stammen nicht von hämatopoetischen oder stromalen Knochenmarkszellen ab. Sie demonstrieren Stammzell-ähnliche Eigenschaften und Fähigkeiten, wie Zellmigration, Proliferation, Klonogenität und Multipotenz der Zelldifferenzierung. Darüber hinaus exprimieren sie Stamm- oder Progenitorzellmarker wie Notch1, Nes und Sca1. Interessanterweise wurden MCCs nur in juvenilen Mäusen gefunden bevor die Tiere das Entwicklungsstadium der Augenlid-Öffnung erreichten. Weiterführende, auch in vivo-Untersuchungen, könnten zukünftig die exakte Rolle und Bedeutung der MCCs für die corneale Entwicklung evaluieren.
Trotz der Tatsache, dass es sich bei MCCs um primäre Zellen handelt, konnten sie erfolgreich für mindestens 60 Passagen subkultiviert werden. Proliferation und CFU-Kapazität der MCCs nahmen bis Passage 10 ab, stiegen aber dann erneut signifikant an. Auch in höheren Passagen exprimierten MCCs Stamm- bzw. Progenitorzellmarker und behielten Stammzell-ähnliche Eigenschaften wie Proliferation, Klonogenität und Multipotenz bei. Jedoch entwickelten MCCs im Laufe der Subkultivierung numerische chromosomale Aberrationen. Die Expression von Tumorsuppressorgenen wie p16 und p21 sank ebenfalls. Dies unterstreicht die Möglichkeit, dass die Stammzell-ähnlichen MCCs nach Langzeit-Kultivierung eine Transformation zu Tumor-ähnlichen Zellen durchlebten, die am wahrscheinlichsten nach Passage 10 und noch vor Passage 15 stattfand. Daher könnte die Verwendbarkeit der MCCs für therapeutische Anwendungen limitiert sein und sollte sich möglicherweise auf Zellen beschränken, die jünger sind als Passage 10, da bis zu dieser Passage die genetische Stabilität der MCCs sichergestellt werden konnte.
Dessen ungeachtet erlaubt und erleichtert die Etablierung einer neuen, stabilen, gut proliferierenden Cornea-Zelllinie, die auch nach extensiver Subkultivierung ihre Multipotenz der Zelldifferenzierung aufrechterhält, zukünftige Studien zur cornealen Zellbiologie oder allgemeinen Stammzellbiologie
Structure-Function Relationship Studies of the Cytochrome Oxidases
No full textFinally, there is evidence of radical migration in the bovine cytochrome c oxidase. Upon formation of the P-state a band was seen by SDS-PAGE analysis that migrated faster than the carbonic anhydrase standard (molecular weight 36800). MALDI-TOF mass spectrometry analysis identified this as a single peak with a m/z of 34336.4, which is exactly twice the mass of subunit IV. It is believed that a covalent linkage of subunit IV is made.Made available in DSpace on 2015-09-25T22:28:30Z (GMT). No. of bitstreams: 2
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Previous issue date: 1999Embargo set by: Seth Robbins for item 86197
Lift date: Forever
Reason: Restricted to the U of I community idenfinitely during batch ingest of legacy ETDsRestricted to the U of I community idenfinitely during batch ingest of legacy ETDsU of I Only101 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1999
New species of Triplocania Roesler with forewing M3 forked (Psocodea: 'Psocoptera': Ptiloneuridae), from Brazil
No full textFour new Brazilian species of Triplocania with forewing M3 forked are described and illustrated based on male speci-mens, namely: Triplocania lamasi n.sp. (Mato Grosso: Brazil), Triplocania mariateresae n.sp. (Rio de Janeiro: Brazil), Triplocania newi n.sp. (Tocantins: Brazil) and Triplocania plaumanni n.sp. (Santa Catarina: Brasil). They differ from all the other species in the genus, in which the males are known, by the hypandrium and phallosome structures. Copyright © 2014 Magnolia Press
data WIFI trial; wound infection following implant removal
No full textMulticenter, double-blind, randomized clinical trial including 500 patients aged 18 to 75 years with previous surgical treatment for fractures below the knee who were undergoing removal of orthopedic implants from 19 hospitals (17 teaching and 2 academic) in the Netherlands (November 2014-September 2016), with a follow-up of 6 months (final follow-up, March 28, 2017). Exclusion criteria were an active infection or fistula, antibiotic treatment, reimplantation of osteosynthesis material in the same session, allergy for cephalosporins, known kidney disease, immunosuppressant use, or pregnancy.INTERVENTIONS:A single preoperative intravenous dose of 1000 mg of cefazolin (cefazolin group, n = 228) or sodium chloride (0.9%; saline group, n = 242).MAIN OUTCOMES AND MEASURES:Primary outcome was SSI within 30 days as measured by the criteria from the US Centers for Disease Control and Prevention. Secondary outcome measures were functional outcome, health-related quality of life, and patient satisfaction.RESULTS:Among 477 randomized patients (mean age, 44 years [SD, 15]; women, 274 [57%]; median time from orthopedic implant placement, 11 months [interquartile range, 7-16]), 470 patients completed the study. Sixty-six patients developed an SSI (14.0%): 30 patients (13.2%) in the cefazolin group vs 36 in the saline group (14.9%) (absolute risk difference, -1.7 [95% CI, -8.0 to 4.6], P = .60).For access to the dataset please contact autho
Characterizing the γ-ray long-term variability of PKS 2155 - 304 with H.E.S.S. and Fermi-LAT
No full textStudying the temporal variability of BL Lac objects at the highest energies provides unique insights into the extreme physical processes occurring in relativistic jets and in the vicinity of super-massive black holes. To this end, the long-term variability of the BL Lac object PKS 2155-304 is analyzed in the high (HE, 100 MeV 200 GeV) γ-ray domain. Over the course of ∼9 yr of H.E.S.S. observations the VHE light curve in the quiescent state is consistent with a log-normal behavior. The VHE variability in this state is well described by flicker noise (power-spectral-density index βVHE = 1.10-0.13+0.10) on timescales larger than one day. An analysis of ∼5.5 yr of HE Fermi-LAT data gives consistent results (βHE = 1.20-0.23+0.21), on timescales larger than 10 days) compatible with the VHE findings. The HE and VHE power spectral densities show a scale invariance across the probed time ranges. A direct linear correlation between the VHE and HE fluxes could neither be excluded nor firmly established. These long-term-variability properties are discussed and compared to the red noise behavior (β ∼ 2) seen on shorter timescales during VHE-flaring states. The difference in power spectral noise behavior at VHE energies during quiescent and flaring states provides evidence that these states are influenced by different physical processes, while the compatibility of the HE and VHE long-term results is suggestive of a common physical link as it might be introduced by an underlying jet-disk connection
Characterizing the γ-ray long-term variability of PKS 2155 - 304 with H.E.S.S. and Fermi-LAT
No full textStudying the temporal variability of BL Lac objects at the highest energies provides unique insights into the extreme physical processes occurring in relativistic jets and in the vicinity of super-massive black holes. To this end, the long-term variability of the BL Lac object PKS 2155-304 is analyzed in the high (HE, 100 MeV 200 GeV) γ-ray domain. Over the course of ∼9 yr of H.E.S.S. observations the VHE light curve in the quiescent state is consistent with a log-normal behavior. The VHE variability in this state is well described by flicker noise (power-spectral-density index βVHE = 1.10-0.13+0.10) on timescales larger than one day. An analysis of ∼5.5 yr of HE Fermi-LAT data gives consistent results (βHE = 1.20-0.23+0.21), on timescales larger than 10 days) compatible with the VHE findings. The HE and VHE power spectral densities show a scale invariance across the probed time ranges. A direct linear correlation between the VHE and HE fluxes could neither be excluded nor firmly established. These long-term-variability properties are discussed and compared to the red noise behavior (β ∼ 2) seen on shorter timescales during VHE-flaring states. The difference in power spectral noise behavior at VHE energies during quiescent and flaring states provides evidence that these states are influenced by different physical processes, while the compatibility of the HE and VHE long-term results is suggestive of a common physical link as it might be introduced by an underlying jet-disk connection
The supernova remnant W49B as seen with HESS and Fermi-LAT
No full textThe supernova remnant (SNR) W49B originated from a core-collapse supernova that occurred between one and four thousand years ago, and subsequently evolved into a mixed-morphology remnant, which is interacting with molecular clouds (MC). Gamma-ray observations of SNR-MC associations are a powerful tool to constrain the origin of Galactic cosmic rays, as they can probe the acceleration of hadrons through their interaction with the surrounding medium and subsequent emission of non-thermal photons. We report the detection of a γ-ray source coincident with W49B at very high energies (VHE; E > 100 GeV) with the H.E.S.S. Cherenkov telescopes together with a study of the source with five years of Fermi-LAT high-energy γ-ray (0.06–300 GeV) data. The smoothly connected, combined source spectrum, measured from 60 MeV to multi-TeV energies, shows two significant spectral breaks at 304 ± 20 MeV and 8.4−2.5+2.2 GeV; the latter is constrained by the joint fit from the two instruments. The detected spectral features are similar to those observed in several other SNR-MC associations and are found to be indicative of γ-ray emission produced through neutral-pion decay
H.E.S.S. observations of RX J1713.7−3946 with improved angular and spectral resolution: Evidence for gamma-ray emission extending beyond the X-ray emitting shell
No full textSupernova remnants exhibit shock fronts (shells) that can accelerate charged particles up to very high energies. In the past decade, measurements of a handful of shell-type supernova remnants in very high-energy gamma rays have provided unique insights into the acceleration process. Among those objects, RX J1713.7−3946 (also known as G347.3−0.5) has the largest surface brightness, allowing us in the past to perform the most comprehensive study of morphology and spatially resolved spectra of any such very high-energy gamma-ray source. Here we present extensive new H.E.S.S. measurements of RX J1713.7−3946, almost doubling the observation time compared to our previous publication. Combined with new improved analysis tools, the previous sensitivity is more than doubled. The H.E.S.S. angular resolution of 0.048° (0.036° above 2 TeV) is unprecedented in gamma-ray astronomy and probes physical scales of 0.8 (0.6) parsec at the remnant’s location. The new H.E.S.S. image of RX J1713.7−3946 allows us to reveal clear morphological differences between X-rays and gamma rays. In particular, for the outer edge of the brightest shell region, we find the first ever indication for particles in the process of leaving the acceleration shock region. By studying the broadband energy spectrum, we furthermore extract properties of the parent particle populations, providing new input to the discussion of the leptonic or hadronic nature of the gamma-ray emission mechanism
A search for new supernova remnant shells in the Galactic plane with H.E.S.S
No full textA search for new supernova remnants (SNRs) has been conducted using TeV γ-ray data from the H.E.S.S. Galactic plane survey. As an identification criterion, shell morphologies that are characteristic for known resolved TeV SNRs have been used. Three new SNR candidates were identified in the H.E.S.S. data set with this method. Extensive multiwavelength searches for counterparts were conducted. A radio SNR candidate has been identified to be a counterpart to HESS J1534−571. The TeV source is therefore classified as a SNR. For the other two sources, HESS J1614−518 and HESS J1912+101, no identifying counterparts have been found, thus they remain SNR candidates for the time being. TeV-emitting SNRs are key objects in the context of identifying the accelerators of Galactic cosmic rays. The TeV emission of the relativistic particles in the new sources is examined in view of possible leptonic and hadronic emission scenarios, taking the current multiwavelength knowledge into account
Population study of Galactic supernova remnants at very high γ-ray energies with H.E.S.S.
No full textShell-type supernova remnants (SNRs) are considered prime candidates for the acceleration of Galactic cosmic rays (CRs) up to the knee of the CR spectrum at E ≈ 3 × 1015 eV. Our Milky Way galaxy hosts more than 350 SNRs discovered at radio wavelengths and at high energies, of which 220 fall into the H.E.S.S. Galactic Plane Survey (HGPS) region. Of those, only 50 SNRs are coincident with a H.E.S.S source and in 8 cases the very high-energy (VHE) emission is firmly identified as an SNR. The H.E.S.S. GPS provides us with a legacy for SNR population study in VHE γ-rays and we use this rich data set to extract VHE flux upper limits from all undetected SNRs. Overall, the derived flux upper limits are not in contradiction with the canonical CR paradigm. Assuming this paradigm holds true, we can constrain typical ambient density values around shell-type SNRs to n ≤ 7 cm−3 and electron-to-proton energy fractions above 10 TeV to ϵep ≤ 5 × 10−3. Furthermore, comparisons of VHE with radio luminosities in non-interacting SNRs reveal a behaviour that is in agreement with the theory of magnetic field amplification at shell-type SNRs
