1,555 research outputs found
Chromoionophores in optical ion sensors
The feasibility of surface plasmon resonance (SPR) for ion sensing has been investigated. Emphasis is laid on a simulation-based optimization of the SP carrying structure, as well as the applicability of a specific chemo—optical interface we have developed. A preliminary result is presented
Surface plasmon resonance immunosensors: sensitivity considerations
Some aspects of improving surface plasmon resonance response in immunosensing applications are considered. Both from calculations and experiments, it was found that maximum sensitivity is obtained for a silver layer about 55 nm thick in direct contact with the species to be quantified. Application of an intermediate layer with high permittivity can be useful in suppressing background responses. Experimentally, a protein surface-coverage fraction of ca. 0.1 could be measured, corresponding to ca. 10−10 mol1−1 antibody
Evolution of a highly dilatant fault zone in the grabens of Canyonlands National Park, Utah, USA - Integrating fieldwork, ground-penetrating radar and airborne imagery analysis
Abstract. The grabens of Canyonlands National Park are a young and active system of sub-parallel, arcuate grabens, whose evolution is the result of salt movement in the subsurface and a slight regional tilt of the faulted strata. We present results of ground-penetrating radar (GPR) surveys in combination with field observations and analysis of high-resolution airborne imagery. GPR data show intense faulting of the Quaternary sediments at the flat graben floors, implying a more complex fault structure than visible at the surface. Direct measurements of heave and throw at several locations to infer fault dips at depth, combined with observations of primary joint surfaces in the upper 100 m, suggest a highly dilatant fault geometry. Sinkholes observed in the field as well as in airborne imagery give insights in local dilatancy and show where water and sediments are transported underground. Based on correlations of paleosols observed in outcrops and GPR profiles, we argue that either the grabens in Canyonlands National Park are older than previously assumed or that sedimentation rates were much higher in the Pleistocene.
This is the final version of the article. It first appeared from Copernicus Publications via http://dx.doi.org/10.5194/se-6-839-2015 The supplement related to this article is available online at http://dx.doi.org/10.5194/se-6-839-2015-supplemen
Епоха "пост": людина в перспективі "нової духовності"
Розглянуто основні проблеми сучасного суспільства, пов’язані із антропологічною кризою, кардинальними змінами у темпоральності, способі буття людини. Проаналізовано ситуацію заміни попередніх гуманістичних ціннісних систем на більш “технізовані”, що призводить до виникнення нового типу людини – “постлюдини”. Посилюється вплив на людей “світу віртуальної реальності”. Нове штучне середовище “сканує”, приймає лише інформаційний аспект людини, вводячи її як цілісну істоту в стан кризи. Доведено актуальність відповідей на смислові запитання епохи, пов’язані із світоглядом, духовністю та цінностями.The main problems of modern society, related to the anthropological crisis, fundamental changes in temporality, ways of human being are considered. There is an analysis of situation of replacing the previous humanistic value systems on a more “technicized”, which causes a new type of man – “posthuman”. The impact on “the world of virtual reality” people is growing. New artifi cial environment “scans”, takes only informational aspect of human, introducing it as complete being in a state of crisis. The urgency of responses to semantic question of the epoch, related to the outlook, spirituality and values is justifi ed
Surface plasmon dispersion and luminescence quenching applied to planar waveguide sensors for the measurement Of chemical concentrations
Two novel types of planar waveguide sensors for the chemical domain are introduced. Both are realized by thin film technologies. They consist of multilayered structures coated by a very thin organic overlayer that is able to absorb the species to be measured out of the environment. This absorbtion results in a change in its dielectric function. In the first sensor to be demonstrated this change is measured using a surface plasmon mode as a probe. In the second one the radiationless energy transfer from luminescent centres incorporated in one of the layers to the overlayer serves as a probe
Studies on Prn Variation in the Mouse Model and Comparison with Epidemiological Data
The virulence factor pertactin (Prn) is a component of pertussis vaccines and one
of the most polymorphic Bordetella pertussis antigens. After
the introduction of vaccination shifts in predominant Prn types were observed
and strains with the Prn vaccine type (Prn1) were replaced by strains carrying
non-vaccine types (Prn2 and Prn3), suggesting vaccine-driven selection. The aim
of this study was to elucidate the shifts observed in Prn variants. We show
that, although Prn2 and Prn3 circulated in similar frequencies in the 1970s and
1980s, in the 1990s Prn2 strains expanded and Prn3 strains disappeared,
suggesting that in vaccinated populations Prn2 strains are fitter than Prn3
strains. We established a role for Prn in the mouse model by showing that a Prn
knock-out (Prn-ko) mutation reduced colonization in trachea and lungs.
Restoration of the mutation resulted in a significant increase in colonization
compared to the knock-out mutant. The ability of clinical isolates with
different Prn variants to colonize the mouse lung was compared. Although these
isolates were also polymorphic at other loci, only variation in the promoter for
pertussis toxin (ptxP) and Prn were found to contribute
significantly to differences in colonization. Analysis of a subset of strains
with the same ptxP allele revealed that the ability to colonize
mice decreased in the order Prn1>Prn2 and Prn3. Our results are consistent
with the predominance of Prn1 strains in unvaccinated populations. Our results
show that ability to colonize mice is practically the same for Prn2 and Prn3.
Therefore other factors may have contributed to the predominance of Prn2 in
vaccinated populations. The mouse model may be useful to assess and predict
changes in the B. pertussis population due to vaccination
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