Light manipulation in a marine diatom

2008 ◽  
Vol 23 (12) ◽  
pp. 3229-3235 ◽  
Author(s):  
Joseph Noyes ◽  
Manfred Sumper ◽  
Pete Vukusic
Keyword(s):  
Experimental Investigation ◽  
Cell Walls ◽  
Marine Diatom ◽  
Centric Diatom ◽  
Diatom Cell ◽  
Diatom Species ◽  
Light Manipulation ◽  
Insight Into ◽  
Periodic Nanostructure

Diatoms are well known for the intricately patterned nanostructure of their silica-based cell walls. To date, the optical properties of diatom cell-wall ultrastructures have largely gone uncharacterized experimentally. Here we report the results of a detailed experimental investigation of the way in which light interacts with the ultrastructure of a representative centric diatom species,Coscinodiscus wailesii. Light interaction both with individual valves and whole bivalves of the diatomC. wailesiiwas measured. Significant sixfold symmetric diffraction through the valve ultrastructure was observed in transmission and quantified to efficiencies that were found to be strongly wavelength dependent; approximately 80% for red, 30% for green, and 20% for blue light. While these results may potentially offer insight into the role of periodic nanostructure in diatom selection, they are also important for consideration in the design of biomimetic optics-based diatom applications.

The role of the diatom cell form in the competition for light energy

2019 ◽  
pp. 37-47
Author(s):  
Aleksey V. Fedorov ◽  
Leonid E. Paramonov ◽  
Vladimir A. Silkin
Keyword(s):  
Ecological Niche ◽  
The Black Sea ◽  
Diatom Cell ◽  
Diatom Species ◽  
Absorbed Energy ◽  
Cell Form ◽  
Different Seasons ◽  
Phytoplankton Cell ◽  
Competition For Light

We proposed a new parameter regulating distribution of the species – the daily average absorbed energy of PAR by a unit of phytoplankton cell volume, determined by the shape, size and concentration of pigments. We calculated this parameter for some dominant diatom species of the northeastern part of the Black Sea and normalize it by the average daily PAR for periods of dominance. We established that for species successfully compete for an ecological niche this parameter should be approximately at the same level in different seasons.

Biosilica Nanofabrication in Diatoms: The Structures and Properties of Regulatory Silaffins

2005 ◽  
Vol 873 ◽  
Author(s):  
Nils Kröger ◽  
Nicole Poulsen
Keyword(s):  
Cell Walls ◽  
Thalassiosira Pseudonana ◽  
Diatom Species ◽  
General Role ◽  
Cylindrotheca Fusiformis ◽  
Genome Data ◽  
Structures And Properties ◽  
Silica Cell ◽  
Species Specific

AbstractDiatoms are a large group of unicellular microalgae encased by silica cell walls that exhibit species-specific, mostly porous micro-and nanopatterns. Previously, from the diatomCylindrotheca fusiformisunique phosphoproteins (termed silaffins) and unusually long polyamine chains (termed LCPA) have been identified and implicated in silica formation. However, analysis of the general role of silaffins in species-specific silica morphogenesis has been hampered by lack of data about silaffins from other diatom species. Recently, we have isolated the five major silaffins from the diatomThalassiosira pseudonanaand aided by the genome data available from this organisms we were able structurally und functionally characterize these molecules. These data clearly support the hypothesis that silaffins play an important role in the nanofabrication of diatom biosilica. The basic insights into the mechanism of biomineral morphogenesis by silaffins and LCPA suggest future pathways for the fabrication of nanostructured minerals by synthetically available polymers.

Plasminogen Activation In Vivo upon Intravenous Infusion of DDAVP

1992 ◽  
Vol 67 (01) ◽  
pp. 111-116 ◽  
Author(s):  
Marcel Levi ◽  
Jan Paul de Boer ◽  
Dorina Roem ◽  
Jan Wouter ten Cate ◽  
C Erik Hack
Keyword(s):  
Monoclonal Antibodies ◽  
Plasminogen Activator ◽  
Plasma Levels ◽  
Fold Increase ◽  
Fibrinolytic System ◽  
Plasminogen Activation ◽  
Plasminogen Activator Activity ◽  
Insight Into

SummaryInfusion of desamino-d-arginine vasopressin (DDAVP) results in an increase in plasma plasminogen activator activity. Whether this increase results in the generation of plasmin in vivo has never been established.A novel sensitive radioimmunoassay (RIA) for the measurement of the complex between plasmin and its main inhibitor α2 antiplasmin (PAP complex) was developed using monoclonal antibodies preferentially reacting with complexed and inactivated α2-antiplasmin and monoclonal antibodies against plasmin. The assay was validated in healthy volunteers and in patients with an activated fibrinolytic system.Infusion of DDAVP in a randomized placebo controlled crossover study resulted in all volunteers in a 6.6-fold increase in PAP complex, which was maximal between 15 and 30 min after the start of the infusion. Hereafter, plasma levels of PAP complex decreased with an apparent half-life of disappearance of about 120 min. Infusion of DDAVP did not induce generation of thrombin, as measured by plasma levels of prothrombin fragment F1+2 and thrombin-antithrombin III (TAT) complex.We conclude that the increase in plasminogen activator activity upon the infusion of DDAVP results in the in vivo generation of plasmin, in the absence of coagulation activation. Studying the DDAVP induced increase in PAP complex of patients with thromboembolic disease and a defective plasminogen activator response upon DDAVP may provide more insight into the role of the fibrinolytic system in the pathogenesis of thrombosis.

On Metaphysics and the Political: A Polemics of Reading Baudelaire in the 1930s

2019 ◽  
Vol 58 (2) ◽  
pp. 249-259
Author(s):  
Joseph Acquisto
Keyword(s):  
Twentieth Century ◽  
Political Crisis ◽  
The Political ◽  
Modern Poetry ◽  
Progressive Politics ◽  
The World ◽  
Relationship Of ◽  
The Relationship ◽  
Insight Into

This essay examines a polemic between two Baudelaire critics of the 1930s, Jean Cassou and Benjamin Fondane, which centered on the relationship of poetry to progressive politics and metaphysics. I argue that a return to Baudelaire's poetry can yield insight into what seems like an impasse in Cassou and Fondane. Baudelaire provides the possibility of realigning metaphysics and politics so that poetry has the potential to become the space in which we can begin to think the two of them together, as opposed to seeing them in unresolvable tension. Or rather, the tension that Baudelaire animates between the two allows us a new way of thinking about the role of esthetics in moments of political crisis. We can in some ways see Baudelaire as responding, avant la lettre, to two of his early twentieth-century readers who correctly perceived his work as the space that breathes a new urgency into the questions of how modern poetry relates to the world from which it springs and in which it intervenes.

Dažu vācu muzikālo tradīciju pārnese latviešu kultūrtelpā 18. gadsimta II pusē

Letonica ◽  
2020 ◽  
Author(s):  
Māra Grudule
Keyword(s):  
18Th Century ◽  
Musical Instrument ◽  
German Society ◽  
Original Form ◽  
Musical Life ◽  
Popular Songs ◽  
Death Of Jesus ◽  
Musical Traditions ◽  
Insight Into

The article gives insight into a specific component of the work of Baltic enlightener Gotthard Friedrich Stender (1714–1796) that has heretofore been almost unexplored — the transfer of German musical traditions to the Latvian cultural space. Even though there are no sources that claim that Stender was a composer himself, and none of his books contain musical notation, the texts that had been translated by Stender and published in the collections “Jaunas ziņģes” (New popular songs, 1774) and “Ziņģu lustes” (The Joy of singing, 1785, 1789) were meant for singing and, possibly, also for solo-singing with the accompaniment of some musical instrument. This is suggested, first, by how the form of the translation corresponds to the original’s form; second, by the directions, oftentimes attached to the text, that indicate the melody; and third, by the genres of the German originals cantata and song. Stender translated several compositions into Latvian including the text of the religious cantata “Der Tod Jesu” (The Death of Jesus, 1755) by composer Karl Heinrich Graun (1754–1759); songs by various composers that were widely known in German society; as well as a collection of songs by the composer Johann Gottlieb Naumann (1741–1801) that, in its original form, was published together with notation and was intended for solo-singing (female vocals) with the accompaniment of a piano. This article reveals the context of German musical life in the second half of the 18th century and explains the role of music as an instrument of education in Baltic-German and Latvian societies.

The Role of Industry-Academia Collaborative Research in Mineral Exploration

2020 ◽  
Author(s):  
James Marlatt
Keyword(s):  
Collaborative Research ◽  
New Technologies ◽  
Mineral Exploration ◽  
Board Members ◽  
Technological Innovations ◽  
Development Programs ◽  
The University ◽  
Insight Into ◽  
Economic Mineral

ABSTRACT Many people may not be aware of the extent of Kurt Kyser's collaboration with mineral exploration companies through applied research and the development of innovative exploration technologies, starting at the University of Saskatchewan and continuing through the Queen's Facility for Isotope Research. Applied collaborative, geoscientific, industry-academia research and development programs can yield technological innovations that can improve the mineral exploration discovery rates of economic mineral deposits. Alliances between exploration geoscientists and geoscientific researchers can benefit both parties, contributing to the pure and applied geoscientific knowledge base and the development of innovations in mineral exploration technology. Through a collaboration that spanned over three decades, we gained insight into the potential for economic uranium deposits around the world in Canada, Australia, USA, Finland, Russia, Gabon, Namibia, Botswana, South Africa, and Guyana. Kurt, his research team, postdoctoral fellows, and students developed technological innovations related to holistic basin analysis for economic mineral potential, isotopes in mineral exploration, and biogeochemical exploration, among others. In this paper, the business of mineral exploration is briefly described, and some examples of industry-academic collaboration innovations brought forward through Kurt's research are identified. Kurt was a masterful and capable knowledge broker, which is a key criterion for bringing new technologies to application—a grand, curious, credible, patient, and attentive communicator—whether talking about science, business, or life and with first ministers, senior technocrats, peers, board members, first nation peoples, exploration geologists, investors, students, citizens, or friends.

An Experimental Investigation of Auditors' Liability: Implications for Social Welfare and Exploration of Deviations from Theoretical Predictions

2000 ◽  
Vol 75 (4) ◽  
pp. 429-451 ◽  
Author(s):  
Ronald R. King ◽  
Rachel Schwartz
Keyword(s):  
Experimental Investigation ◽  
Social Welfare ◽  
Strict Liability ◽  
Liability Rule ◽  
Optimal Response ◽  
Legal Regimes ◽  
Theoretical Predictions ◽  
Best Responses

This paper reports the results of an experiment designed to investigate how legal regimes affect social welfare. We investigate four legal regimes, each consisting of a liability rule (strict or negligence) and a damage measure (out-of-pocket or independent-of-investment). The results of the experiment are for the most part consistent with the qualitative predictions of Schwartz's (1997) model; however, subjects' actual choices deviate from the point predictions of the model. We explore whether these deviations arise because: (1) subjects form faulty anticipations of their counterparts' actions and/or (2) subjects do not choose the optimal responses given their anticipations. We find that subjects behave differently under the four regimes in terms of anticipation errors and departures from best responses. For example, subjects playing the role of auditors anticipate investments most accurately under the regime with strict liability combined with out-of-pocket damages, but are least likely to choose the optimal response given their anticipations. This finding implies that noneconomic factors likely play a role in determining subjects' choices.

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