Polyyne bridges have attracted extensive interest as molecular wires due to their shallow distance dependence during charge transfer. Here, we investigate whether triplet energy transfer from cadmium selenide (CdSe) quantum dots (QDs) to anthracene acceptors benefits from the high conductance associated with polyyne bridges, especially from the potential cumulene character in their excited states. Introducing π-electron rich oligoyne bridges between the surface-bound anthracene-based transmitter ligands, we explore the triplet energy transfer rate between the CdSe QDs and anthracene core.
View Article and Find Full Text PDFThe structural factors affecting triplet-triplet annihilation (TTA) at the molecular level are not well-understood. Here, our steady-state photoluminescence and transient absorption results demonstrate that the spin statistical factor, η, decreases from 0.60 to 0.
View Article and Find Full Text PDFThe sinew channels are a tendon and muscle network, and their description is based on the observation presented on the Huangdi Neijing Ling Shu. However, the myofascial system is an uninterrupted series of connective tissue that is comprised of layers that run in different directions. The similarities on these pathways are compared, such as a brief description on the myofascial pain syndrome and its similitude with the Impediment disorder from the Traditional Chinese Medicine (TCM).
View Article and Find Full Text PDFLTR-retrotransposons are the most abundant repeat sequences in plant genomes and play an important role in evolution and biodiversity. Their characterization is of great importance to understand their dynamics. However, the identification and classification of these elements remains a challenge today.
View Article and Find Full Text PDFTransposable elements are mobile sequences that can move and insert themselves into chromosomes, activating under internal or external stimuli, giving the organism the ability to adapt to the environment. Annotating transposable elements in genomic data is currently considered a crucial task to understand key aspects of organisms such as phenotype variability, species evolution, and genome size, among others. Because of the way they replicate, LTR retrotransposons are the most common transposable elements in plants, accounting in some cases for up to 80% of all DNA information.
View Article and Find Full Text PDFEvery day more plant genomes are available in public databases and additional massive sequencing projects (i.e., that aim to sequence thousands of individuals) are formulated and released.
View Article and Find Full Text PDFLong terminal repeat (LTR) retrotransposons are mobile elements that constitute the major fraction of most plant genomes. The identification and annotation of these elements via bioinformatics approaches represent a major challenge in the era of massive plant genome sequencing. In addition to their involvement in genome size variation, LTR retrotransposons are also associated with the function and structure of different chromosomal regions and can alter the function of coding regions, among others.
View Article and Find Full Text PDFIn triplet-triplet annihilation based photon upconversion, controlling triplet energy transfer (TET) through the system is key to unlocking higher efficiencies. In this work, we vary the size of colloidally synthesized CdSe nanocrystals (NCs) to examine the effects on TET during photon upconversion, using steady-state measurements and transient absorption spectroscopy. As the CdSe NC size increases, the photon upconversion quantum yield (QY) decreases due to the decrease in the rate of TET from CdSe to the surface bound anthracene transmitter ligand, as expected for the Marcus description of energy transfer from the transmitter to the NC.
View Article and Find Full Text PDFCBE Life Sci Educ
September 2020
While interdisciplinary collaboration is desired among researchers, traditional science instruction generally results in science disciplines being taught as separate entities. This study focuses on student understanding of concepts at the intersection of two isolated disciplines-geoscience and bioscience-across two purposeful samples of college-aged students (United States, Germany). Specifically, we explored: 1) how students conceptualize large-scale biologic and geologic changes on Earth over deep time; 2) the relationship between student's conceptions and their understanding of evolutionary and geologic theories; and 3) how those conceptualizations explicate the need for integration of concepts within school curricula.
View Article and Find Full Text PDFPhoton upconversion employing semiconductor nanocrystals (NCs) makes use of their large and tunable absorption to harvest light in the near-infrared (NIR) wavelengths as well as their small gap between singlet and triplet excited states to reduce energy losses. Here, we report the highest QY (11.8%) thus far for the conversion of NIR to yellow photons by improving the quality of the PbS NC.
View Article and Find Full Text PDFInterdisciplinary scientific research teams are essential for responding to society's complex scientific and social issues. Perceptual barriers to collaboration can inhibit the productivity of teams crossing traditional disciplinary boundaries. To explore these perceptual barriers, survey measures related to perceived competence were developed and validated with a population of earth scientists (n = 449) ranging from undergraduates through professionals.
View Article and Find Full Text PDFIntroduction: The aim of the present study was to evaluate clinical presentation and management of sigmoid volvulus in children. Sigmoid volvulus is one of the three leading causes of acute obstruction of the colon and is between 50 and 90% of all large bowel volvulus. In the pediatric population only 3 to 5% of bowel obstructions are caused by volvulus and there are less than 100 cases reported in the literature.
View Article and Find Full Text PDFBackground: Testing connectivity among populations of exploited marine fish is a main concern for the development of conservation strategies. Even though marine species are often considered to display low levels of population structure, barriers to dispersal found in the marine realm may restrict gene flow and cause genetic divergence of populations. The Pacific Sierra mackerel (Scomberomorus sierra) is a pelagic fish species distributed throughout the tropical and subtropical waters of the eastern Pacific.
View Article and Find Full Text PDFWildfires in Mexico increased in 1998, compared to information for the last 6 years. The average number of wildfires in the Mexico City Metropolitan Area (MCMA) for this year (1998) were 58% (1916 events) more events than the 1992-1997 (average cases 1217 events). Mexico City affected area corresponds to 1.
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