29 research outputs found
Variations on a theme: diversification of cuticular hydrocarbons in a clade of cactophilic Drosophila
<p>Abstract</p> <p>Background</p> <p>We characterized variation and chemical composition of epicuticular hydrocarbons (CHCs) in the seven species of the <it>Drosophila buzzatii </it>cluster with gas chromatography/mass spectrometry. Despite the critical role of CHCs in providing resistance to desiccation and involvement in communication, such as courtship behavior, mating, and aggregation, few studies have investigated how CHC profiles evolve within and between species in a phylogenetic context. We analyzed quantitative differences in CHC profiles in populations of the <it>D. buzzatii </it>species cluster in order to assess the concordance of CHC differentiation with species divergence.</p> <p>Results</p> <p>Thirty-six CHC components were scored in single fly extracts with carbon chain lengths ranging from C<sub>29 </sub>to C<sub>39</sub>, including methyl-branched alkanes, <it>n</it>-alkenes, and alkadienes. Multivariate analysis of variance revealed that CHC amounts were significantly different among all species and canonical discriminant function (CDF) analysis resolved all species into distinct, non-overlapping groups. Significant intraspecific variation was found in different populations of <it>D. serido </it>suggesting that this taxon is comprised of at least two species. We summarized CHC variation using CDF analysis and mapped the first five CHC canonical variates (CVs) onto an independently derived <it>period </it>(<it>per</it>) gene + chromosome inversion + mtDNA COI gene for each sex. We found that the COI sequences were not phylogenetically informative due to introgression between some species, so only <it>per </it>+ inversion data were used. Positive phylogenetic signal was observed mainly for CV1 when parsimony methods and the test for serial independence (TFSI) were used. These results changed when no outgroup species were included in the analysis and phylogenetic signal was then observed for female CV3 and/or CV4 and male CV4 and CV5. Finally, removal of divergent populations of <it>D. serido </it>significantly increased the amount of phylogenetic signal as up to four out of five CVs then displayed positive phylogenetic signal.</p> <p>Conclusions</p> <p>CHCs were conserved among species while quantitative differences in CHC profiles between populations and species were statistically significant. Most CHCs were species-, population-, and sex-specific. Mapping CHCs onto an independently derived phylogeny revealed that a significant portion of CHC variation was explained by species' systematic affinities indicating phylogenetic conservatism in the evolution of these hydrocarbon arrays, presumptive waterproofing compounds and courtship signals as in many other drosophilid species.</p
Emissions from a modern log wood masonry heater and wood pellet boiler : Composition and biological impact on air-liquid interface exposed human lung cancer cells
The consumption of wood fuel is markedly increasing in developing and industrialized countries. Known side effects of wood smoke inhalation manifest in proinflammatory signaling, oxidative stress, DNA damage and hence increased cancer risk. In this study, the composition and acute biological impact of emissions of state-of-the-art wood combustion compliances: masonry heater (MH) and pellet boiler (PB) were investigated. Therefore A549 cells were exposed to emission aerosols in an automated air-liquid interface exposure station followed by cytotoxicity, transcriptome and proteome analyses. In parallel, aerosols were subjected to a chemical and physical haracterization. Compared to PB, the MH combustion at the same dilution ratio resulted in a 3-fold higher particle mass concentration (PM2.5) and deposited dose (PB: 27 2 ng/cm2, MH; 73 12 ng/cm2). Additionally, the MH aerosol displayed a substantially larger concentration of aldehydes, polycyclic aromatic hydrocarbons (PAH) or oxidized PAH. Gene ontology analysis of transcriptome of A549 cells exposed to MH emissions revealed the activation of proinflammatory response and key signaling cascades MAP kinase and JAK-STAT. Furthermore, CYP1A1, an essential enzyme in PAH metabolism, was induced. PB combustion aerosol activated the proinflammatory marker IL6 and different transport processes. The proteomics data uncovered induction of DNA damage-associated proteins in response to PB and DNA doublestrand break processing proteins in response to MH emissions. Taking together, the MH produces emissions with a higher particle dose and more toxic compounds while causing only mild biological responses. This finding points to a significant mitigating effect of antioxidative compounds in MH wood smoke
Compilation of suitable safety indicators for the evaluation of Human-Machine Interaction of level 3 systems
Mit dem Ziel, geeignete Indikatoren und Kriterien für die Bewertung der sicheren Mensch-Maschine-Interaktion für SAE Level 3 Systeme bis 60 km/h im Kontext des automatisierten Fahrens zu identifizieren, wurde dieses Forschungsprojekt mit einem Fokusgruppeninterview begonnen, um relevante Publikationskanäle und eine Liste von Schlüsselwörtern bezüglich Indikatoren für die Bewertung der Mensch-Maschine-Interaktion auf SAE Level 3 zu identifizieren. Basierend auf der identifizierten Liste von Schlüsselwörtern wurde eine Literaturrecherche durchgeführt, um relevante Publikationen aus den identifizierten Publikationskanälen zu extrahieren. Anhand der definierten Ein- und Ausschlusskriterien wurden 38 Arbeiten ausgewählt und für eine Meta-Analyse verwendet, um den Einfluss verschiedener Übernahmesituationen auf die Übernahmeleistung zu untersuchen. Die Ergebnisse der Meta-Analyse haben gezeigt, dass die Übernahmeleistungen der Fahrer, gemessen an den Kategorien Übernahmezeit, Übernahmequalität und subjektive Arbeitsbeanspruchung, in statischen und dynamischen Situationen unterschiedlich sind. Anschließend wurden Experteninterviews mit sechs internationalen Experten durchgeführt, um die Ergebnisse der Metaanalyse zu interpretieren und Checklistenelemente zu entwickeln. Am Ende wurden 16 Checklistenpunkte entwickelt, die sechs Kategorien von Systemanforderungen zugeordnet sind und von internationalen Experten zur Bewertung der Sicherheit der Mensch-Maschine-Interaktion von SAE Level 3 Systemen bis zu 60 km/h in Serienfahrzeugen verwendet werden können. Diese Checkliste wurde zu einer Online-Anwendung weiterentwickelt, die als einfach zu implementierendes und effizientes Bewertungsverfahren in Bezug auf die verkehrssicherheitsrelevante Interaktionsqualität der Systeme genutzt werden kann
Zusammenstellung geeigneter Sicherheitsindikatoren für die Bewertung der Mensch-Maschine-Interaktion von Level 3 Systemen
With the aim of identifying suitable indicators and criteria for evaluating the safe human-machine interaction for SAE level 3 systems up to 60 km/h in the context of automated driving, this research project has started with a focus group interview to identify relevant publication channels and list of keywords regarding indicators for the evaluation of human-machine interaction at SAE Level 3. Based on the identified list of keywords, literature reviews have been conducted to extract relevant publications from the identified publication channels. According to the defined inclusion and exclusion criterion, 38 papers have then been selected and used for meta-analysis to study the influence of different takeover situations on takeover performances. The results of meta-analysis have indicated that drivers’ takeover performances measured by the categories of takeover time, takeover quality and subjective workload are different in static and dynamic situations. After that, expert interviews have been conducted with six international experts to help interpret the results of meta-analysis and develop checklist items. In the end, 16 checklist items assigned in six categories of system requirements have been developed and can be used by international experts to evaluate the safety of the human-machine interaction of SAE Level 3 systems up to 60 km/h in production vehicles. This checklist has been further developed to an online application, which can be used as an easy-to-implement and efficient evaluation procedure in relation to the traffic safety relevant interaction quality of the system
A new access to diazaphospholes via cycloaddition–cycloreversion reactions on triazaphospholes
A novel bis-CF3-substituted diazaphosphole was synthesized selectively from hexafluoro-2-butyne and a 3H-1,2,3,4-triazaphosphole derivative. The [4+2] cycloaddition and subsequent cycloreversion reaction under elimination of pivaloyl nitrile affords the product in high yield. The heterocycle coordinates via the phosphorus atom to a W(CO)5-fragment and shows stronger π-accepting properties than the triazaphosphole
Hyphenation of Thermal Analysis to Ultrahigh-Resolution Mass Spectrometry (Fourier Transform Ion Cyclotron Resonance Mass Spectrometry) Using Atmospheric Pressure Chemical Ionization For Studying Composition and Thermal Degradation of Complex Materials
In this study, the hyphenation of
a thermobalance to an ultrahigh-resolution
Fourier transform ion cyclotron resonance mass spectrometer (UHR FTICR
MS) is presented. Atmospheric pressure chemical ionization (APCI)
is used for efficient ionization. The evolved gas analysis (EGA),
using high-resolution mass spectrometry allows the time-resolved molecular
characterization of thermally induced processes in complex materials
or mixtures, such as biomass or crude oil. The most crucial part of
the setup is the hyphenation between the thermobalance and the APCI
source. Evolved gases are forced to enter the atmospheric pressure
ionization interface of the MS by applying a slight overpressure at
the thermobalance side of the hyphenation. Using the FTICR exact mass
data, detailed chemical information is gained by calculation of elemental
compositions from the organic species, enabling a time and temperature
resolved, highly selective detection of the evolved species. An additional
selectivity is gained by the APCI ionization, which is particularly
sensitive toward polar compounds. This selectivity on the one hand
misses bulk components of petroleum samples such as alkanes and does
not deliver a comprehensive view but on the other hand focuses particularly
on typical evolved components from biomass samples. As proof of principle,
the thermal behavior of different fossil fuels: heavy fuel oil, light
fuel oil, and a crude oil, and different lignocellulosic biomass,
namely, beech, birch, spruce, ash, oak, and pine as well as commercial
available softwood and birch-bark pellets were investigated. The results
clearly show the capability to distinguish between certain wood types
through their molecular patterns and compound classes. Additionally,
typical literature known pyrolysis biomass marker were confirmed by
their elemental composition, such as coniferyl aldehyde (C<sub>10</sub>H<sub>10</sub>O<sub>3</sub>), sinapyl aldehyde (C<sub>11</sub>H<sub>12</sub>O<sub>4</sub>), retene (C<sub>18</sub>H<sub>18</sub>), and
abietic acid (C<sub>20</sub>H<sub>30</sub>O<sub>2</sub>)
On-Line Process Analysis of Biomass Flash Pyrolysis Gases Enabled by Soft Photoionization Mass Spectrometry
In the current discussion about future energy and fuel
supply based on regenerative energy sources, the so-called second-generation
biofuels represent a vitally important contribution for the provision
of carbon-based fuels. In this framework, at the Karlsruhe Institute
of Technology (KIT), the bioliq process has been developed, by which
biomass is flash-pyrolyzed at 500 °C for the production of so-called
biosyncrude, a suspension of the pyrolysis liquids and the remaining
biochar. However, little is known about the composition of the pyrolysis
gases in this process with regard to different biomass feedstock and
process conditions, and the influence on the subsequent steps, namely,
the gasification and subsequent production of biofuels or base materials.
Time-of-flight mass spectrometry (TOFMS) with two soft (i.e., fragmentation
free) photoionization techniques was for the first time applied for
on-line monitoring of the signature organic compounds in highly complex
pyrolysis gases at a technical pyrolysis pilot plant at the KIT. Resonance-enhanced
multiphoton ionization with TOFMS using UV laser pulses was used for
selective and sensitive detection of aromatic species. Furthermore,
single-photon ionization using VUV light supplied by an electron beam-pumped
excimer light source was used to comprehensively ionize (nearly) all
organic molecules. For the miscellaneous biomass feeds used, distinguishable
mass spectra with specific patterns could be obtained, mainly exhibiting
typical pyrolytic decomposition products of (hemi)cellulose and lignin
(phenol derivatives), and nitrogen-containing compounds in some cases.
Certain biomasses are differentiated by their ratios of specific groups
of phenolic decomposition products. Therefore, principal component
and cluster analysis describes the varied pyrolysis gas composition
for temperature variations and particularly for different biomass
species. The results can be integrated in the optimization of the
bioliq process