2,474 research outputs found
Flour protein antigens in occupational flour hypersensitivity
Thirty serum samples from clinical cases of flour hypersensitivity were analyzed for wheat or rye flour protein antibodies. The patients included 20 bakers and 10 others who also had occupational flour exposure. Twenty-three cases had antiflour antibodies which recognized antigens other than control sera in the flour protein patterns. The immunologic response of individual cases seemed very variable in view of the numerous differences between the cases in the antigen-antibody reactions. For the practical purposes, the flour protein antigens were divided in three groups, i.e., those larger than 80 kDa, those between 80 and 50 kDa and those smaller than 50 kDa. Cases with flour-induced dermatitis (n=8) showed sensitization towards antigens in all size classes while those with rhinitis or asthma showed more antigens with a molecular weight less than 50 kDa. The test offers a possibility to independently verify an exposure to flour while it does not substitute for the conventional immunologic diagnostic test
Exposure to glycols and their renal effects in motor servicing workers
Ten car mechanics frequently exposed to glycol-based cooling liquids were followed during a workshift. Airborne ethylene and propylene glycol concentrations in the car mechanics' environment were measured. The car mechanics gave urine samples after the workshift and their excretion of ethylene glycol, propylene glycol, oxalic acid, calcium and ammonia was analysed and compared to that of unexposed office workers. Urinary succinate dehydrogenase activity and glycosaminoglycans were also measured in both groups. Airborne ethylene and propylene glycol concentrations in the car mechanics' environment were negligible. Urinary ethylene glycol excretion in exposed workers was significantly higher than that in unexposed workers, but propylene glycol excretion was at the same level as in controls. In the exposed group, the excretion of the end metabolite of ethylene glycol, oxalic acid (47 ± 11 mmol/mol creatinine, mean ± SD, n= 10) differed slightly from that of controls (36 ± 14 mmol/mol creatinine, mean ± SD, n= 10). Urinary excretion of ammonia was higher among exposed workers than office workers. The excretion of calcium did not differ from that of controls. A marginally decreased urinary succinate dehydrogenase activity was found in the exposed men. The excretion of glycosaminoglycans was significantly lower in exposed workers. Therefore, it seems that ethylene glycol is absorbed by skin contact. The internal body burden is associated with oxaluria and increased ammoniagenesis typical of chronic acidosi
Shuntchirurgie in Europa und den USA: Ein kritischer Vergleich
Zusammenfassung: Nach einem anfänglich gemeinsamen Weg in der Fistelchirurgie begann in den USA ab etwa 1975 der bevorzugte Einsatz von Prothesenshunts. In bis zu 80% wurden bei Erstoperationen Gefäßprothesen implantiert, mit entsprechend hoher Komplikationsrate und hohen Folgekosten. Europa pflegte, mit lokalen Unterschieden, das Konzept der vorzugsweisen Verwendung von arteriovenösen Fisteln weiter (AVF). Der Prothesenanteil war nie höher als 40%. Unterstützt von Richtlinien, versuchen die USA seit 1997 einen deutlichen Umschwung herbeizuführen. Der Anteil primärer AVF ist seither angestiegen, bei allerdings wohl erhöhter initialer Versagerquote im internationalen Vergleich. Über Richtlinien hinaus sollte für beide Kontinente als vordringliche Aufgaben die interdisziplinäre Zusammenarbeit aller beteiligten Fachgebiete gelten: Durchführung zertifizierter, interdisziplinärer Kurse mit konsensfähigen Inhalten, Einrichtung von Referenzzentren mit einheitlicher, umfassender Dokumentation, Aufbau von Datenbanken zur Qualitätskontrolle mit abrufbaren Komplikations- und Funktionsraten, Standardisierung der Überwachung von Gefäßzugängen im Dialysezentru
Chloroplast microsatellites: measures of genetic diversity and the effect of homoplasy
Chloroplast microsatellites have been widely used in population genetic
studies of conifers in recent years. However, their haplotype configurations
suggest that they could have high levels of homoplasy, thus limiting the power
of these molecular markers. A coalescent-based computer simulation was used to
explore the influence of homoplasy on measures of genetic diversity based on
chloroplast microsatellites. The conditions of the simulation were defined to
fit isolated populations originating from the colonization of one single
haplotype into an area left available after a glacial retreat. Simulated data
were compared with empirical data available from the literature for a species
of Pinus that has expanded north after the Last Glacial Maximum. In the
evaluation of genetic diversity, homoplasy was found to have little influence
on Nei's unbiased haplotype diversity (H(E)) while Goldstein's genetic distance
estimates (D2sh) were much more affected. The effect of the number of
chloroplast microsatellite loci for evaluation of genetic diversity is also
discussed
Catching the radio flare in CTA 102 I. Light curve analysis
Context: The blazar CTA 102 (z=1.037) underwent a historical radio outburst
in April 2006. This event offered a unique chance to study the physical
properties of the jet. Aims: We used multifrequency radio and mm observations
to analyze the evolution of the spectral parameters during the flare as a test
of the shock-in-jet model under these extreme conditions. Methods: For the
analysis of the flare we took into account that the flaring spectrum is
superimposed on a quiescent spectrum. We reconstructed the latter from archival
data and fitted a synchrotron self-absorbed distribution of emission. The
uncertainties of the derived spectral parameters were calculated using Monte
Carlo simulations. The spectral evolution is modeled by the shock-in-jet model,
and the derived results are discussed in the context of a geometrical model
(varying viewing angle) and shock-shock interaction. Results: The evolution of
the flare in the turnover frequency-turnover flux density plane shows a double
peak structure. The nature of this evolution is dicussed in the frame of
shock-in-jet models. We discard the generation of the double peak structure in
the turnover frequency-turnover flux density plane purely based on geometrical
changes (variation of the Doppler factor). The detailed modeling of the
spectral evolution favors a shock-shock interaction as a possible physical
mechanism behind the deviations from the standard shock-in-jet model.Comment: 15 pages, 12 figure
Vibronic coupling explains the ultrafast carotenoid-to-bacteriochlorophyll energy transfer in natural and artificial light harvesters
The initial energy transfer in photosynthesis occurs between the
light-harvesting pigments and on ultrafast timescales. We analyze the
carotenoid to bacteriochlorophyll energy transfer in LH2 Marichromatium
purpuratum as well as in an artificial light-harvesting dyad system by using
transient grating and two-dimensional electronic spectroscopy with 10 fs time
resolution. We find that F\"orster-type models reproduce the experimentally
observed 60 fs transfer times, but overestimate coupling constants, which leads
to a disagreement with both linear absorption and electronic 2D-spectra. We
show that a vibronic model, which treats carotenoid vibrations on both
electronic ground and excited state as part of the system's Hamiltonian,
reproduces all measured quantities. Importantly, the vibronic model presented
here can explain the fast energy transfer rates with only moderate coupling
constants, which are in agreement with structure based calculations.
Counterintuitively, the vibrational levels on the carotenoid electronic ground
state play a central role in the excited state population transfer to
bacteriochlorophyll as the resonance between the donor-acceptor energy gap and
vibrational ground state energies is the physical basis of the ultrafast energy
transfer rates in these systems
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