Assessment of Wall Elasticity Variations on Intraluminal Haemodynamics in Descending Aortic Dissections Using a Lumped-Parameter Model

Descending aortic dissection (DAD) is associated with high morbidity and mortality rates. Aortic wall stiffness is a variable often altered in DAD patients and potentially involved in long-term outcome. However, its relevance is still mostly unknown. To gain more detailed knowledge of how wall elasticity (compliance) might influence intraluminal haemodynamics in DAD, a lumped-parameter model was developed based on experimental data from a pulsatile hydraulic circuit and validated for 8 clinical scenarios. Next, the variations of intraluminal pressures and flows were assessed as a function of wall elasticity. In comparison with the most rigid-wall case, an increase in elasticity to physiological values was associated with a decrease in systolic and increase in diastolic pressures of up to 33% and 63% respectively, with a subsequent decrease in the pressure wave amplitude of up to 86%. Moreover, it was related to an increase in multidirectional intraluminal flows and transition of behaviour as 2 parallel vessels towards a vessel with a side-chamber. The model supports the extremely important role of wall elasticity as determinant of intraluminal pressures and flow patterns for DAD, and thus, the relevance of considering it during clinical assessment and computational modelling of the disease.     

Reversible coupling of individual phycobiliprotein isoforms during state transitions in the cyanobacterium Trichodesmium analysed by single-cell fluorescence kinetic measurements

In the non-heterocyst, marine cyanobacterium Trichodesmium nitrogen fixation is confined to the photoperiod and occurs coevally with oxygenic photosynthesis although nitrogenase is irreversibly inactivated by oxygen. In previous studies it was found that regulation of photosynthesis for nitrogen fixation involves Mehler reaction and various activity states with reversible coupling of photosynthetic components. We now investigated these activity states in more detail. Spectrally resolved fluorescence kinetic measurements of single cells revealed that they were related to alternate uncoupling and coupling of phycobilisomes from and to the photosystems, changing the effective cross-section of PSII. Therefore, we isolated and purified the phycobiliproteins of Trichodesmium via ion exchange chromatography and recorded their UV/VIS absorption, fluorescence excitation and fluorescence emission spectra. After describing these spectra by mathematical equations via the Gauss-Peak-Spectra method, we used them to deconvolute the in vivo fluorescence spectra of Trichodesmium cells. This revealed that the contribution of different parts of the phycobilisome antenna to fluorescence quenching changed during the daily activity cycle, and that individual phycobiliproteins can be reversibly coupled to the photosystems, while the expression levels of these proteins did not change much during the daily activity cycle. Thus we propose that variable phycobilisome coupling plays a key role in the regulation of photosynthesis for nitrogen fixation in Trichodesmium.     

Intraspecific genetic variation of a Fagus sylvatica population in a temperate forest derived from airborne imaging spectroscopy time series

1. The growing pace of environmental change has increased the need for large‐scale monitoring of biodiversity. Declining intraspecific genetic variation is likely a critical factor in biodiversity loss, but is especially difficult to monitor: assessments of genetic variation are commonly based on measuring allele pools, which requires sampling of individuals and extensive sample processing, limiting spatial coverage. Alternatively, imaging spectroscopy data from remote platforms may hold the potential to reveal genetic structure of populations. In this study, we investigated how differences detected in an airborne imaging spectroscopy time series correspond to genetic variation within a population of Fagus sylvatica under natural conditions.
2. We used multi‐annual APEX (Airborne Prism Experiment) imaging spectrometer data from a temperate forest located in the Swiss midlands (Laegern, 47°28'N, 8°21'E), along with microsatellite data from F. sylvatica individuals collected at the site. We identified variation in foliar reflectance independent of annual and seasonal changes which we hypothesize is more likely to correspond to stable genetic differences. We established a direct connection between the spectroscopy and genetics data by using partial least squares (PLS) regression to predict the probability of belonging to a genetic cluster from spectral data.
3. We achieved the best genetic structure prediction by using derivatives of reflectance and a subset of wavebands rather than full‐analyzed spectra. Our model indicates that spectral regions related to leaf water content, phenols, pigments, and wax composition contribute most to the ability of this approach to predict genetic structure of F. sylvatica population in natural conditions.
4. This study advances the use of airborne imaging spectroscopy to assess tree genetic diversity at canopy level under natural conditions, which could overcome current spatiotemporal limitations on monitoring, understanding, and preventing genetic biodiversity loss imposed by requirements for extensive in situ sampling.

     

Contextual effects in the perception of quinine HCl/NaCl mixtures

Stimulus distribution, stimulus spacing and stimulus range affectmean intensity ratings of solutions of unmixed tastants. Thepresent study compares contextual effects for mixture ratingswith those for unmixed stimuli: if ratings for mixed and unmixedstimuli are differentially affected by context, the degree ofmixture suppression inferred from the responses is context-dependent.Bitterness intensity ratings for unmixed quinine and quinineHCl/NaCl mixtures were not differentially affected by shiftsin stimulus frequency distribution. The subjects' tendency tobe consistent in their responses to identical stimuli, resultsin a transfer of stimulus context of previous sessions to thenext.     

Contribution to the knowledge of Thai microfauna diversity: notes on rare peat swamp Rotifera, with the description of a new Lecane Nitzsch, 1872

During an ongoing study of the rotifer diversity in Thai peat swamps, several new or rare species were found. We here report on one new species, Lecane kunthuleensis n.sp., from a canal in Kun Thu Lee peat swamp, and on three rare species: Paracolurella aemula (Myers, 1934) and Lecane junkiKoste, 1975 from Kra Jood peat swamp (Suratthanee province), and Lepadella punctataWulfert, 1939 from To-Daeng peat swamp (Narathiwas province).     

Xerotolerant Cladosporium sphaerospermum Are Predominant on Indoor Surfaces Compared to Other Cladosporium Species

Indoor fungi are a major cause of cosmetic and structural damage of buildings worldwide and prolonged exposure of these fungi poses a health risk. Aspergillus, Penicillium and Cladosporium species are the most predominant fungi in indoor environments. Cladosporium species predominate under ambient conditions. A total of 123 Cladosporium isolates originating from indoor air and indoor surfaces of archives, industrial factories, laboratories, and other buildings from four continents were identified by sequencing the internal transcribed spacer (ITS), and a part of the translation elongation factor 1α gene (TEF) and actin gene (ACT). Species from the Cladosporium sphaerospermum species complex were most predominant representing 44.7% of all isolates, while the Cladosporium cladosporioides and Cladosporium herbarum species complexes represented 33.3% and 22.0%, respectively. The contribution of the C. sphaerospermum species complex was 23.1% and 58.2% in the indoor air and isolates from indoor surfaces, respectively. Isolates from this species complex showed growth at lower water activity (≥ 0.82) when compared to species from the C. cladosporioides and C. herbarum species complexes (≥ 0.85). Together, these data indicate that xerotolerance provide the C. sphaerospermum species complex advantage in colonizing indoor surfaces. As a consequence, C. sphaerospermum are proposed to be the most predominant fungus at these locations under ambient conditions. Findings are discussed in relation to the specificity of allergy test, as the current species of Cladosporium used to develop these tests are not the predominant indoor species.