A single chromophore can only emit a maximum of one single photon per excitation cycle. This limitation results in a phenomenon commonly referred to as photon antibunching (pAB). When multiple chromophores contribute to the fluorescence measured, the degree of pAB has been used as a metric to "count" the number of chromophores.
View Article and Find Full Text PDFObjectives: The European University Association (EUA) defines "employability" as a major goal of higher education. Therefore, competence-based orientation is an important aspect of education. The representation of a standardized job profile in the field of medical informatics, which is based on the most common labor market requirements, is fundamental for identifying and conveying the learning goals corresponding to these competences.
View Article and Find Full Text PDFBy measuring the fluorescence photon statistics of single chains of a conjugated polymer, we determine the lifetime of the metastable dark state, the triplet exciton. The single molecule emits single photons one at a time, giving rise to photon antibunching. These photons appear bunched in time over longer time scales because of excursions to the triplet dark state.
View Article and Find Full Text PDFMost measurements of fluorescence lifetimes on the single-molecule level are carried out using avalanche photon diodes (APDs). These single-photon counters are inherently slow, and their response shows a strong dependence on photon energy, which can make reconvolution of the instrument response function (IRF) challenging. An ultrafast time resolution in single-molecule fluorescence is crucial, e.
View Article and Find Full Text PDFClimate change has altered global precipitation patterns and has led to greater variation in hydrological conditions. Wetlands are important globally for their soil carbon storage. Given that wetland carbon processes are primarily driven by hydrology, a comprehensive understanding of the effect of inundation is needed.
View Article and Find Full Text PDFSeveral long non-coding RNAs (lncRNAs) act as regulators of cellular homeostasis; however, few of these molecules were functionally characterized in a mature human tissue environment. Here, we report that the lncRNA LINC00941 is a crucial regulator of human epidermal homeostasis. LINC00941 is enriched in progenitor keratinocytes and acts as a repressor of keratinocyte differentiation.
View Article and Find Full Text PDFEcotypic differentiation in the tussock-forming sedge has led to the development of populations that are locally adapted to climate in Alaska's moist tussock tundra. As a foundation species, plays a central role in providing topographic and microclimatic variation essential to these ecosystems, but a changing climate could diminish the importance of this species. As Arctic temperatures have increased, there is evidence of adaptational lag in , as locally adapted ecotypes now exhibit reduced population growth rates.
View Article and Find Full Text PDFThe breaking of molecular symmetry through photoexcitation is a ubiquitous but rather elusive process, which, for example, controls the microscopic efficiency of light harvesting in molecular aggregates. A molecular excitation within a π-conjugated segment will self-localize due to strong coupling to molecular vibrations, locally changing bond alternation in a process which is fundamentally nondeterministic. Probing such symmetry breaking usually relies on polarization-resolved fluorescence, which is most powerful on the level of single molecules.
View Article and Find Full Text PDFThis research examines the relationships between El Niño Southern Oscillation (ENSO), water level, precipitation patterns and carbon dioxide (CO2) exchange rates in the freshwater wetland ecosystems of the Florida Everglades. Data was obtained over a 5-year study period (2009-2013) from two freshwater marsh sites located in Everglades National Park that differ in hydrology. At the short-hydroperiod site (Taylor Slough; TS) and the long-hydroperiod site (Shark River Slough; SRS) fluctuations in precipitation patterns occurred with changes in ENSO phase, suggesting that extreme ENSO phases alter Everglades hydrology which is known to have a substantial influence on ecosystem carbon dynamics.
View Article and Find Full Text PDFCarbon (C) exchange of an approximately 200-year-old eastern hemlock (Tsuga canadensis L.) forest in central Massachusetts, USA, was estimated from mid-October 2000 through October 2001 based on eddy covariance measurements and statistical modeling from microclimatic data. Measurements were made in 68% of the hours during the year of study, with > 50% coverage in all months except December and August.
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