3,347 research outputs found
The electronic structure of the lutein triplet state in plant light-harvesting complex II
No full textCarotenoid molecules are essential for the life of photosynthetic organisms in that they protect the cell from the photo-oxidative damage induced by light-stress conditions. One of the photo-protective mechanisms involves triplet-triplet energy transfer from the chlorophyll molecules to the carotenoids: a process that is strongly dependent on the electronic properties of the triplet states involved. Here, we obtain a clear description of the triplet state of lutein in LHCII from higher plants for the first time by density functional theory (DFT) calculations. DFT predictions have been validated by comparison with hyperfine couplings obtained with pulsed-ENDOR spectroscopy. Knowledge of the spin density distribution, the frontier orbitals and orbital excitations forms a basis for discussing the requirements for an efficient triplet-triplet energy transfer. The results obtained for the lutein in LHCII are compared with those of the highly-substituted carotenoid peridinin in PCP from Amphidinium carterae [Di Valentin et al., Biochim. Biophys. Acta, 2008, 1777, 295-307]. The presence of substituents in the peridinin molecule does not alter significantly the triplet state electronic structure compared to lutein. Despite the unusual spectroscopic behaviour of the peridinin excited singlet state, lutein and peridinin have similar triplet state properties. In both molecules the unpaired spins are delocalized uniformly over the whole pi-conjugated system in an alternating even-odd pattern
Triplet–triplet energy transfer in fucoxanthin-chlorophyll protein from diatom Cyclotella meneghiniana: Insights into the structure of the complex
No full textAlthough the major light harvesting complexes of diatoms, called FCPs (fucoxanthin chlorophyll a/c binding proteins), are related to the cab proteins of higher plants, the structures of these light harvesting protein complexes are much less characterized. Here, a structural/functional model for the “core” of FCP, based on the sequence homology with LHCII, in which two fucoxanthins replace the central luteins and act as quenchers of the Chl a triplet states, is proposed. Combining the information obtained by time-resolved EPR spectroscopy on the triplet states populated under illumination, with quantum mechanical calculations, we discuss the chlorophyll triplet quenching in terms of the geometry of the chlorophyll–carotenoid pairs participating to the process. The results show that local structural rearrangements occur in FCP, with respect to LHCII, in the photoprotective site
South Australian experience with pediatric total pancreatectomy and islet autotransplantation for PRSS1-associated hereditary pancreatitis
No full textPerspectivesJessica Eldredge, Michael R Couper, David J Moore, Sanjeev Khurana, John WC Chen, Jennifer J Couper, Christopher J Drogemuller, Toni Radford, Thomas W Kay, Tom Loudovaris, Michael Wilks, Patrick T Coates, Richard TL Coupe
Oberflächenmodifizierung von Kohlenstoffmaterialien durch Pyrolyse phosphorhaltiger Ionischer Flüssigkeiten für Brennstoffzellenanwendungen
No full textElektrochemische Systeme wie Brennstoffzellen sind Schlüsseltechnologien, die zur nachhal-tigen Gesellschaft beitragen. Die kommerzielle Nutzung ist durch hohe Kosten sowie niedrige Langlebigkeit und Leistung limitiert. Phosphorhaltige Kohlenstoffe können als Trägermaterial für Edelmetallkatalysatoren dienen, um Leistung und Haltbarkeit von Kathoden im Brenn-stoffzellenbetrieb zu erhöhen. Eine Nassimprägnierung von Kohlenstoffen mit Ionischen Flüs-sigkeiten und anschließender Pyrolyse bei 400°C erzeugte homogen verteilte PO3- und PO4-artige Phosphorspezies mit Phosphorgehältern von bis zu 3,0 Gew. %. Brennstoffzellentests offenbarten, dass geringe Mengen Phosphor positive Effekte auf Schlüsseleigenschaften von phosphordotierten Proben haben. Dazu zählen erhöhte Leistung und Haltbarkeit sowie signifi-kant verringerte Ladungswiderstände an der Kathode. Die Aktivität der Sauerstoffredukti-onsreaktion konnte ebenfalls erhöht werden, ohne die Morphologie und Geometrie der Sub-strate zu beeinflussen. Aufgrund veränderter Bindungslängen, Atomradien und Elektronega-tivität von Phosphor erfolgt eine Modifizirung der Oberflächenzusammensetzung, welche die Beobachtungen erklärt. Ionische Flüssigkeiten konnten erfolgreich als Imprägnierungsreagenz für die Herstellung von heteroatomdotierten Kohlenstoffen genutzt werden, der Prozess ist auf verschiedenste Kohlenstoffsubstrate anwendbar. Die Verbesserung verschiedener Schlüs-seleigenschaften kann bestehende Mängel entweder mildern oder ausgleichen.Electrochemical devices such as fuel cells are key technologies towards a sustainable society. The widespread utilization is limited by high costs, as well as low longevity and performance. Phosphorus containing carbon materials can serve as support for noble metal catalysts to in-crease both performance and durability of cathodes in fuel cell application. A simple wet im-pregnation method using ionic liquids followed by a subsequent pyrolysis at 400°C yielded homogeneous distributed PO3- and PO4-like species with a total content of up to 3.0 wt. % phosphorus. Small phosphorus contents in phosphorus coated materials resulted in positive effects on key characteristics. Fuel cell testing revealed increased durability and performance, as well as significantly reduced charge transfer resistances at the cathodes. Additionally, the materials showed increased ORR activity without altering the morphology or geometry of the substrates. These observations can be assigned to changed binding lengths, atom radii and electron negativity of the introduced phosphorus, altering the surface composition. Ionic liq-uids themselves proved as coating agents for the fabrication of heteroatom containing carbons, with a coating process applicable to various carbon substrates. The improvement of different key characterics may compensate the shortcomings for a widespread utilization of fuel cells or other electrochemical devices.Forschungsnetzwerk Mittelstand AIF/IGF - Vorhaben-Nr. 18 EW - „Langzeitstabile Phosphor dotierte Legierungs-Katalysatoren und Phosphor dotierte Kohlenstoff-Substrate für Hochleistungs-PEM-Brennstoffzellen durch Pulse-Plating-Abscheidung
The Bean Beetle Microbiome Project: A Course-Based Undergraduate Research Experience in Microbiology
No full textCourse-based undergraduate research experiences (CUREs) are an effective means of transforming the learning and teaching of science by involving students in the scientific process. The potential importance of the microbiome in shaping both environmental health and disease makes investigations of microbiomes an excellent teaching tool for undergraduate microbiology. Here, we present a CURE based on the microbiome of the bean beetle (Callosobruchus maculatus), a model system for undergraduate laboratory education.
“Taming” and “Unfamiliarity”: A Landscape To Be Told
No full textThe article concerns the way in which the cultural landscape of the so-called Recovered Territories was “tamed” after 1945 and today. The author juxtaposes the diagnosis of Jacek Kolbuszewski with Olga Tokarczuk’s contradictory opinion. In his article “Oswajanie krajobrazu kulturowego. Z problematyki integracji kulturowej na Ziemiach Odzyskanych” [Taming cultural landscape. On the problem of cultural integration on the Recovered Territores] (1988), Kolbuszewski states that the process of integration was successfully completed in the second half of the 1950s. Tokarczuk’s essay “Bezimienny krajobraz” [Nameless landscape] (included in the book Nieswojość [strangeness], 2019) contradicts the thesis of successful adaptation in the ‘post-German’ territories. According to Tokarczuk, the prerequisite for such adaptation is the recognition of the inhabited space as one’s own, which is achieved through the naming of the ‘nameless landscape’ and the stories about the place. Christopher Tilley’s concept of cultural landscape, which emphasises the relationship between narratives and space, resonates with this position. In reference to this concept and using the illustation of Filip Springer’s reportage as well as Krzysztof Fedorowicz’s novel, the author of the article demonstrates how contemporary literature concerning the Lower Silesia develops a bond with the place and tames the ‘post-German’ landscape on new [email protected]łgorzata Mikołajczak, prof. dr hab., kierowniczka Zakładu Literaturoznawstwa w Instytucie Filologii Polskiej Uniwersytetu Zielonogórskiego, członkini Komitetu Nauk o Literaturze PAN. Autorka monografii poświęconych poezji Urszuli Kozioł i Zbigniewa Herberta, autorka i współredaktorka monografii na temat literackiego regionalizmu. Opracowała Wybór poezji Zbigniewa Herberta w serii Biblioteka Narodowa (Wrocław 2018). Ostatnio wydała Ramiona Antajosa. Z teorii i historii regionalizmu literackiego w Polsce (2021).Wydział Humanistyczny, Uniwersytet ZielonogórskiFedorowicz Krzysztof (2020), Zaświaty. Opowieści o nieprzemijaniu, Kraków: Wysoki Zamek.Heidegger Martin (1974), Budować, mieszkać, myśleć, przeł. K. Michalski, „Teksty: Teoria Literatury, Krytyka, Interpretacja”, nr 6, s. 137–152.Kolbuszewski Jacek (1988), Oswajanie krajobrazu. Z problematyki integracji kulturowej na Ziemiach Odzyskanych, w: Symbolika regionów. Studia etnologiczno-folklorystyczne, red. D. Simonides, Opole: Instytut Śląski w Opolu, s. 67–82.Leśniakowska Marta (2019), Taki pejzaż. Fenomenologia fotograficznej weduty, w: Nieswojość, red. A. Pankiewicz, M. Przybyłko, Wrocław: Wrocławskie Wydawnictwo Warstwy, s. 139–149.Sakson Andrzej (2020), Specyfika przemian społecznych na Ziemiach Nowych, w: A. Sakson, Nowe społeczeństwo Ziem Zachodnich i Północnych (1945–2020), Poznań: Wydawnictwo Naukowe Wydziału Nauk Politycznych i Dziennikarstwa.Sendyka Roma (2015), Krajobrazy (nie)pamięci: dekonstrukcja krajobrazu kulturowego, w: Więcej niż obraz, red. E. Wilk, A. Nacher, M. Zdrodowska, E. Twardoch i M. Gulik, Gdańsk: WN Katedra.Springer Filip (2014), Mein Gott, jak pięknie, Kraków: Karakter.Sztyber Radosław (2022), „Tu, czyli tam”. O czasie i szacunku (wybrane aspekty prozy Krzysztofa Fedorowicza), w: Prace aksjologiczne. Język – literatura – kultura, t. 3, red. M. Kaczor, P. Kładoczny, Zielona Góra: Oficyna Wydawnicza Uniwersytetu Zielonogórskiego, s. 377–399.Tilley Christopher (2014), Praktykowanie krajobrazu (fragment z Fenomenologii krajobrazu), tłum. D. Stadnik, w: Krajobrazy. Antologia tekstów, teksty zebrały, opracowały i komentarzem opatrzyły B. Frydryczak i D. Angutek, Poznań: Wydawnictwo Poznańskiego Towarzystwa Przyjaciół Nauk, s. 411–422.Tokarczuk Olga (2019), Bezimienny krajobraz, w: Nieswojość, red. A. Pankiewicz, M. Przybyłko, Wrocław: Wrocławskie Wydawnictwo Warstwy, s. 173–180.2571
sj-pdf-1-jrs-10.1177_01410768231182389 - Supplemental material for COVID-19 risk mitigation in reopening mass cultural events: population-based observational study for the UK Events Research Programme in Liverpool City Region
No full textSupplemental material, sj-pdf-1-jrs-10.1177_01410768231182389 for COVID-19 risk mitigation in reopening mass cultural events: population-based observational study for the UK Events Research Programme in Liverpool City Region by Girvan Burnside, Christopher P Cheyne, Gary Leeming, Michael Humann, Alistair Darby, Mark A Green, Alexander Crozier, Simon Maskell, Kay O’Halloran, Elena Musi, Elinor Carmi, Naila Khan, Debra Fisher, Rhiannon Corcoran, Jake Dunning, W John Edmunds, Kukatharmini Tharmaratnam, David M Hughes, Liora Malki-Epshtein, Malcolm Cook, Ben M Roberts, Eileen Gallagher, Kate Howell, Meera Chand, Robin Kemp, Matthew Boulter, Tom Fowler, Malcolm G Semple, Emer Coffey, Matt Ashton, The COVID-19 Genomics UK (COG-UK) Consortium, Marta García-Fiñana and Iain E Buchan in Journal of the Royal Society of Medicine</p
sj-pdf-5-jrs-10.1177_01410768231182389 - Supplemental material for COVID-19 risk mitigation in reopening mass cultural events: population-based observational study for the UK Events Research Programme in Liverpool City Region
No full textSupplemental material, sj-pdf-5-jrs-10.1177_01410768231182389 for COVID-19 risk mitigation in reopening mass cultural events: population-based observational study for the UK Events Research Programme in Liverpool City Region by Girvan Burnside, Christopher P Cheyne, Gary Leeming, Michael Humann, Alistair Darby, Mark A Green, Alexander Crozier, Simon Maskell, Kay O’Halloran, Elena Musi, Elinor Carmi, Naila Khan, Debra Fisher, Rhiannon Corcoran, Jake Dunning, W John Edmunds, Kukatharmini Tharmaratnam, David M Hughes, Liora Malki-Epshtein, Malcolm Cook, Ben M Roberts, Eileen Gallagher, Kate Howell, Meera Chand, Robin Kemp, Matthew Boulter, Tom Fowler, Malcolm G Semple, Emer Coffey, Matt Ashton, The COVID-19 Genomics UK (COG-UK) Consortium, Marta García-Fiñana and Iain E Buchan in Journal of the Royal Society of Medicine</p
sj-pdf-3-jrs-10.1177_01410768231182389 - Supplemental material for COVID-19 risk mitigation in reopening mass cultural events: population-based observational study for the UK Events Research Programme in Liverpool City Region
No full textSupplemental material, sj-pdf-3-jrs-10.1177_01410768231182389 for COVID-19 risk mitigation in reopening mass cultural events: population-based observational study for the UK Events Research Programme in Liverpool City Region by Girvan Burnside, Christopher P Cheyne, Gary Leeming, Michael Humann, Alistair Darby, Mark A Green, Alexander Crozier, Simon Maskell, Kay O’Halloran, Elena Musi, Elinor Carmi, Naila Khan, Debra Fisher, Rhiannon Corcoran, Jake Dunning, W John Edmunds, Kukatharmini Tharmaratnam, David M Hughes, Liora Malki-Epshtein, Malcolm Cook, Ben M Roberts, Eileen Gallagher, Kate Howell, Meera Chand, Robin Kemp, Matthew Boulter, Tom Fowler, Malcolm G Semple, Emer Coffey, Matt Ashton, The COVID-19 Genomics UK (COG-UK) Consortium, Marta García-Fiñana and Iain E Buchan in Journal of the Royal Society of Medicine</p
sj-pdf-4-jrs-10.1177_01410768231182389 - Supplemental material for COVID-19 risk mitigation in reopening mass cultural events: population-based observational study for the UK Events Research Programme in Liverpool City Region
No full textSupplemental material, sj-pdf-4-jrs-10.1177_01410768231182389 for COVID-19 risk mitigation in reopening mass cultural events: population-based observational study for the UK Events Research Programme in Liverpool City Region by Girvan Burnside, Christopher P Cheyne, Gary Leeming, Michael Humann, Alistair Darby, Mark A Green, Alexander Crozier, Simon Maskell, Kay O’Halloran, Elena Musi, Elinor Carmi, Naila Khan, Debra Fisher, Rhiannon Corcoran, Jake Dunning, W John Edmunds, Kukatharmini Tharmaratnam, David M Hughes, Liora Malki-Epshtein, Malcolm Cook, Ben M Roberts, Eileen Gallagher, Kate Howell, Meera Chand, Robin Kemp, Matthew Boulter, Tom Fowler, Malcolm G Semple, Emer Coffey, Matt Ashton, The COVID-19 Genomics UK (COG-UK) Consortium, Marta García-Fiñana and Iain E Buchan in Journal of the Royal Society of Medicine</p
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