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https://www.readbyqxmd.com/read/28333471/competition-between-light-induced-and-intrinsic-nonadiabatic-phenomena-in-diatomics
#1
András Csehi, Gábor J Halász, Lorenz S Cederbaum, Ágnes Vibók
Nonadiabatic effects arise due to avoided crossings or conical intersections that are either present naturally in field-free space or induced by a classical laser field in a molecule. Recently, it was demonstrated that nonadiabatic effects in diatomics can also be created in an optical cavity. Here, the quantized radiation field mixes the nuclear and electronic degrees of freedom. We show the equivalence of using the cavity's quantized field and the classical laser field as usually done for molecules. This is demonstrated for NaI, which exhibits a pronounced natural (intrinsic) avoided crossing that competes with the avoided crossing induced by the field...
March 24, 2017: Journal of Physical Chemistry Letters
https://www.readbyqxmd.com/read/28333196/identification-of-highly-divergent-diatom-derived-chloroplasts-in-dinoflagellates-including-a-description-of-durinskia-kwazulunatalensis-sp-nov-peridiniales-dinophyceae
#2
Norico Yamada, Stuart D Sym, Takeo Horiguchi
Dinoflagellates are known to possess chloroplasts of multiple origins derived from a red alga, a green alga, haptophytes, or diatoms. The monophyletic "dinotoms" harbor a chloroplast of diatom origin, but their chloroplasts are polyphyletic belonging to one of four genera: Chaetoceros, Cyclotella, Discostella, or Nitzschia. It has been speculated that serial replacement of diatom-derived chloroplasts by other diatoms has caused this diversity of chloroplasts. Although previous work suggested that the endosymbionts of Nitzschia origin might not be monophyletic, this has not been seriously investigated...
February 21, 2017: Molecular Biology and Evolution
https://www.readbyqxmd.com/read/28332478/addressed-immobilization-of-biofunctionalized-diatoms-on-electrodes-by-gold-electrodeposition
#3
S Leonardo, D Garibo, M Fernández-Tejedor, C K O'Sullivan, M Campàs
Diatoms are single cell microalgae with a silica shell (frustule), which possess a micro/nanoporous pattern of unparalleled diversity far beyond the possibilities of current micro- and nanofabrication techniques. To explore diatoms as natural three-dimensional nanostructured supports in sensing and biosensing devices, a simple, rapid and stable method to immobilize diatoms via gold electrodeposition is described. In this process, gold microstructures are formed, immobilizing diatoms by entrapment or crossing their nanopores...
March 23, 2017: Biofabrication
https://www.readbyqxmd.com/read/28330359/communication-vibrational-relaxation-of-co-1-%C3%AE-in-collision-with-ar-1-s-at-temperatures-relevant-to-the-hypersonic-flight-regime
#4
Otoniel Denis-Alpizar, Raymond J Bemish, Markus Meuwly
Vibrational energy relaxation (VER) of diatomics following collisions with the surrounding medium is an important elementary process for modeling high-temperature gas flow. VER is characterized by two parameters: the vibrational relaxation time τvib and the state relaxation rates. Here the vibrational relaxation of CO(ν=0←ν=1) in Ar is considered for validating a computational approach to determine the vibrational relaxation time parameter (pτvib) using an accurate, fully dimensional potential energy surface...
March 21, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28328165/variation-in-growth-rate-carbon-assimilation-and-photosynthetic-efficiency-in-response-to-nitrogen-source-and-concentration-in-phytoplankton-isolated-from-upper-san-francisco-bay
#5
Gry Mine Berg, Sara Driscoll, Kendra Hayashi, Melissa Ross, Raphael Kudela
Six species of phytoplankton recently isolated from upper San Francisco Bay were tested for their sensitivity to growth inhibition by ammonium (NH4(+) ), and for differences in growth rates according to inorganic nitrogen (N) growth source. The quantum yield of photosystem II (Fv /Fm ) was a sensitive indicator of NH4(+) toxicity, manifested by a suppression of Fv /Fm in a dose-dependent manner. Two chlorophytes were the least sensitive to NH4(+) inhibition, at concentrations of >3000 μmoles NH4(+) · L(-1) , followed by two estuarine diatoms which were sensitive at concentrations >1000 μmoles NH4(+) · L(-1) , followed lastly by two freshwater diatoms that were sensitive at concentrations between 200-500 μmoles NH4(+) · L(-1) ...
March 22, 2017: Journal of Phycology
https://www.readbyqxmd.com/read/28328041/sem-microphotogrammetry-a-new-take-on-an-old-method-for-generating-high-resolution-3d-models-from-sem-images
#6
A D Ball, P A Job, A E L Walker
The method we present here uses a scanning electron microscope programmed via macros to automatically capture dozens of images at suitable angles to generate accurate, detailed three-dimensional (3D) surface models with micron-scale resolution. We demonstrate that it is possible to use these Scanning Electron Microscope (SEM) images in conjunction with commercially available software originally developed for photogrammetry reconstructions from Digital Single Lens Reflex (DSLR) cameras and to reconstruct 3D models of the specimen...
March 22, 2017: Journal of Microscopy
https://www.readbyqxmd.com/read/28325350/corrigendum-to-exploring-the-status-of-motility-lipid-bodies-deformities-and-size-reduction-in-periphytic-diatom-community-from-chronically-metal-polluted-cu-zn-polluted-waterbodies-as-a-biomonitoring-tool-sci-total-environ-550-2016-372-381
#7
https://www.readbyqxmd.com/read/28318115/microbial-players-and-processes-involved-in-phytoplankton-bloom-utilization-in-the-water-column-of-a-fast-flowing-river-dominated-estuary
#8
Maria W Smith, Lydie Herfort, Caroline S Fortunato, Byron C Crump, Holly M Simon
Fueled by seasonal phytoplankton blooms, the Columbia River estuary is a natural bioreactor for organic matter transformations. Prior metagenome analyses indicated high abundances of diverse Bacteroidetes taxa in estuarine samples containing phytoplankton. To examine the hypothesis that Bacteroidetes taxa have important roles in phytoplankton turnover, we further analyzed metagenomes from water collected along a salinity gradient at 0, 5, 15, 25, and 33 PSU during bloom events. Size fractions were obtained by using a 3-μm prefilter and 0...
March 20, 2017: MicrobiologyOpen
https://www.readbyqxmd.com/read/28317130/influence-of-thylakoid-membrane-lipids-on-the-structure-of-aggregated-light-harvesting-complexes-of-the-diatom-thalassiosira-pseudonana-and-the-green-alga-mantoniella-squamata
#9
Susann Schaller-Laudel, Dariusz Latowski, Małgorzata Jemioła-Rzemińska, Kazimierz Strzałka, Sebastian Daum, Kirsten Bacia, Christian Wilhelm, Reimund Goss
The study investigated the effect of the thylakoid membrane lipids monogalactosyldiacylglycerol (MGDG), digalactosyldiacylglycerol (DGDG), sulphoquinovosyldiacylglycerol (SQDG) and phosphatidylglycerol (PG) on the structure of two algal light-harvesting complexes (LHC). In contrast to higher plants whose thylakoid membranes are characterized by an enrichment of the neutral galactolipids MGDG and DGDG, both the green alga Mantoniella squamata and the centric diatom Thalassiosira pseudonana contain membranes with a high content of the negatively charged lipids SQDG and PG...
March 20, 2017: Physiologia Plantarum
https://www.readbyqxmd.com/read/28314903/diatoms-in-drowning-cases-in-forensic-veterinary-context-a-preliminary-study
#10
Nadia Fucci, Carlo P Campobasso, L Mastrogiuseppe, C Puccinelli, S Marcheggiani, L Mancini, L Marino, V L Pascali
In this preliminary study, a digestive method used in forensic context to extract diatoms has been applied in organs taken from ten wildlife animals belonging three species of mammals (a deer, a roe and five otters) and one species of birds (two magpies). Only four carcasses were recovered from aquatic environments (bath trough for animals, bathtub irrigation, river) and only in three cases out of ten that the cause of death was ruled out as drowning. In seven cases, the death was due to other causes: gunshot injuries for one otter, blunt trauma for a magpie, and traumatic injuries followed by motor vehicle collision in other four otters and a roe...
March 17, 2017: International Journal of Legal Medicine
https://www.readbyqxmd.com/read/28314230/toxicity-of-diatom-polyunsaturated-aldehydes-to-marine-bacterial-isolates-reveals-their-mode-of-action
#11
Milva Pepi, Hermann J Heipieper, Cecilia Balestra, Marco Borra, Elio Biffali, Raffaella Casotti
Diatoms produce and release polyunsaturated aldehydes (PUAs) during senescence in culture and at the end of blooms in nature and these compounds play different ecological roles, as infochemicals, allelochemicals and pheromones In order to elucidate the toxic effects of PUAs, we isolated six bacterial strains from the Mediterranean Sea during a diatom bloom and tested their tolerance to PUA in terms of growth and cell membrane properties. Based upon 16S rRNA sequencing, these bacteria were assigned to the genera Pseudomonas, Sufflavibacter, Halomonas, Vibrio, Idiomarina, and Labrenzia...
March 9, 2017: Chemosphere
https://www.readbyqxmd.com/read/28303313/significant-change-in-marine-plankton-structure-and-carbon-production-after-the-addition-of-river-water-in-a-mesocosm-experiment
#12
E Fouilland, A Trottet, C Alves-de-Souza, D Bonnet, T Bouvier, M Bouvy, S Boyer, L Guillou, E Hatey, H Jing, C Leboulanger, E Le Floc'h, H Liu, S Mas, B Mostajir, J Nouguier, D Pecqueur, E Rochelle-Newall, C Roques, C Salles, M-G Tournoud, C Vasseur, F Vidussi
Rivers are known to be major contributors to eutrophication in marine coastal waters, but little is known on the short-term impact of freshwater surges on the structure and functioning of the marine plankton community. The effect of adding river water, reducing the salinity by 15 and 30%, on an autumn plankton community in a Mediterranean coastal lagoon (Thau Lagoon, France) was determined during a 6-day mesocosm experiment. Adding river water brought not only nutrients but also chlorophyceans that did not survive in the brackish mesocosm waters...
March 16, 2017: Microbial Ecology
https://www.readbyqxmd.com/read/28301562/diversity-and-community-structure-of-cyanobacteria-and-other-microbes-in-recycling-irrigation-reservoirs
#13
Ping Kong, Patricia Richardson, Chuanxue Hong
Recycling irrigation reservoirs (RIRs) are emerging aquatic environments of global significance to crop production, water conservation and environmental sustainability. This study characterized the diversity and population structure of cyanobacteria and other detected microbes in water samples from eight RIRs and one adjacent runoff-free stream at three ornamental crop nurseries in eastern (VA1 and VA3) and central (VA2) Virginia after cloning and sequencing the 16S rRNA gene targeting cyanobacteria and chloroplast of eukaryotic phytoplankton...
2017: PloS One
https://www.readbyqxmd.com/read/28297980/role-of-structure-in-the-%C3%AE-and-%C3%AE-dynamics-of-a-simple-glass-forming-liquid
#14
D Fragiadakis, C M Roland
The elusive connection between dynamics and local structure in supercooled liquids is an important piece of the puzzle in the unsolved problem of the glass transition. The Johari-Goldstein β relaxation, ubiquitous in glass-forming liquids, exhibits mean properties that are strongly correlated to the long-time α dynamics. However, the former comprises simpler, more localized motion, and thus has perhaps a more straightforward connection to structure. Molecular dynamics simulations were carried out on a two-dimensional, rigid diatomic molecule (the simplest structure exhibiting a distinct β process) to assess the role of the local liquid structure on both the Johari-Goldstein β and the α relaxation...
February 2017: Physical Review. E
https://www.readbyqxmd.com/read/28297908/kink-antikink-asymmetry-and-impurity-interactions-in-topological-mechanical-chains
#15
Yujie Zhou, Bryan Gin-Ge Chen, Nitin Upadhyaya, Vincenzo Vitelli
We study the dynamical response of a diatomic periodic chain of rotors coupled by springs, whose unit cell breaks spatial inversion symmetry. In the continuum description, we derive a nonlinear field theory which admits topological kinks and antikinks as nonlinear excitations but where a topological boundary term breaks the symmetry between the two and energetically favors the kink configuration. Using a cobweb plot, we develop a fixed-point analysis for the kink motion and demonstrate that kinks propagate without the Peierls-Nabarro potential energy barrier typically associated with lattice models...
February 2017: Physical Review. E
https://www.readbyqxmd.com/read/28296897/ice-cover-is-the-principal-driver-of-ecological-change-in-high-arctic-lakes-and-ponds
#16
Katherine Griffiths, Neal Michelutti, Madeline Sugar, Marianne S V Douglas, John P Smol
Recent climate change has been especially pronounced in the High Arctic, however, the responses of aquatic biota, such as diatoms, can be modified by site-specific environmental characteristics. To assess if climate-mediated ice cover changes affect the diatom response to climate, we used paleolimnological techniques to examine shifts in diatom assemblages from ten High Arctic lakes and ponds from Ellesmere Island and nearby Pim Island (Nunavut, Canada). The sites were divided a priori into four groups ("warm", "cool", "cold", and "oasis") based on local elevation and microclimatic differences that result in differing lengths of the ice-free season, as well as about three decades of personal observations...
2017: PloS One
https://www.readbyqxmd.com/read/28296259/taxonomy-free-molecular-diatom-index-for-high-throughput-edna-biomonitoring
#17
Laure Apothéloz-Perret-Gentil, Arielle Cordonier, François Straub, Jennifer Iseli, Philippe Esling, Jan Pawlowski
Current biodiversity assessment and biomonitoring are largely based on the morphological identification of selected bioindicator taxa. Recently, several attempts have been made to use eDNA metabarcoding as an alternative tool. However, until now, most applied metabarcoding studies have been based on the taxonomic assignment of sequences that provides reference to morphospecies ecology. Usually, only a small portion of metabarcoding data can be used due to a limited reference database and a lack of phylogenetic resolution...
March 14, 2017: Molecular Ecology Resources
https://www.readbyqxmd.com/read/28294216/strategies-to-enhance-the-excitation-energy-transfer-efficiency-in-a-light-harvesting-system-using-the-intra-molecular-charge-transfer-character-of-carotenoids
#18
Nao Yukihira, Yuko Sugai, Masazumi Fujiwara, Daisuke Kosumi, Masahiko Iha, Kazuhiko Sakaguchi, Shigeo Katsumura, Alastair T Gardiner, Richard J Cogdell, Hideki Hashimoto
Fucoxanthin is a carotenoid that is mainly found in light-harvesting complexes from brown algae and diatoms. Due to the presence of a carbonyl group attached to polyene chains in polar environments, excitation produces an excited intra-molecular charge transfer. This intra-molecular charge transfer state plays a key role in the highly efficient (∼95%) energy-transfer from fucoxanthin to chlorophyll a in the light-harvesting complexes from brown algae. In purple bacterial light-harvesting systems the efficiency of excitation energy-transfer from carotenoids to bacteriochlorophylls depends on the extent of conjugation of the carotenoids...
March 15, 2017: Faraday Discussions
https://www.readbyqxmd.com/read/28289404/different-types-of-diatom-derived-extracellular-polymeric-substances-drive-changes-in-heterotrophic-bacterial-communities-from-intertidal-sediments
#19
Julio Bohórquez, Terry J McGenity, Sokratis Papaspyrou, Emilio García-Robledo, Alfonso Corzo, Graham J C Underwood
Intertidal areas support extensive diatom-rich biofilms. Such microphytobenthic (MPB) diatoms exude large quantities of extracellular polymeric substances (EPS) comprising polysaccharides, glycoproteins and other biopolymers, which represent a substantial carbon pool. However, degradation rates of different EPS components, and how they shape heterotrophic communities in sediments, are not well understood. An aerobic mudflat-sediment slurry experiment was performed in the dark with two different EPS carbon sources from a diatom-dominated biofilm: colloidal EPS (cEPS) and the more complex hot-bicarbonate-extracted EPS...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28285260/microsatellite-markers-for-population-genetic-applications-in-the-domoic-acid-producing-diatom-pseudo-nitzschia-australis-frenguelli-bacillariophyceae
#20
Nicolaus G Adams, Piper Schwenke, G Jason Smith, Vera L Trainer
Microsatellites are commonly used markers in population genetics and are increasingly being employed to determine population structure in phytoplankton populations. We have developed seven polymorphic microsatellite markers for the domoic-acid producing diatom Pseudo-nitzschia australis. Using these markers, thirty P. australis isolates were genotyped, 10 isolates were from Monterey Bay, California and 20 were from off the northern coast of Oregon. The number of alleles per locus ranged from two to eight and observed heterozygosities ranged from 0...
January 26, 2017: Protist
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