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Статті в журналах з теми "H-270"
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Nicosia, Michael, Ran Fan, Satoshi Miyairi, George W. Farr, Paul R. McGuirk, Marc F. Pelletier, Ashley Beavers, and Anna Valujskikh. "Aquaporin 4 blockade alters T cell trafficking through a novel mechanism of S1PR1 regulation." Journal of Immunology 200, no. 1_Supplement (May 1, 2018): 55.33. http://dx.doi.org/10.4049/jimmunol.200.supp.55.33.
Повний текст джерелаАнотація:
Abstract The water channels aquaporins mediate a variety of immune functions. We previously demonstrated that aquaporin 4 (AQP4) is expressed by CD4 and CD8 T cells and blockade of AQP4 with small molecule inhibitor AER-270/271 significantly prolongs survival of heart allografts in two robust models of rejection. The goal of this study was to determine the effects of AQP4 blockade on T cells. Administration of AER-271 into naïve non-transplanted mice (250 μg i.p. every 6 h on d. 0–4) decreased numbers of circulating CD4 and CD8 T cells, but not B cells, by >90%, compared to untreated controls. The T cell frequencies and numbers in the secondary lymphoid organs (SLOs) were not significantly affected by AER-271, suggesting the lack of circulating T cells is not due to systemic depletion but rather to altered T cell trafficking. The effect of AER-271 treatment was transient, as circulating T cell numbers returned to pretreatment levels by d 21. AER-271 treated animals promptly rejected heart allografts transplanted 24 d after treatment cessation (MST 6 d, n=4). We next tested the effects of AQP4 blockade on Sphingosine-1 Phosphate Receptor 1 (S1PR1), a key mediator of T cell trafficking. S1PR1 mRNA expression was reduced in isolated mouse spleen T cells within 3 h of in vitro incubation with AER-270. Decreased S1PR1 mRNA expression translated into altered chemotaxis, as AER-270 reduced T cell migration toward S1PR1 ligand, Sphingosine-1 Phosphate (S1P), in a transwell system. Our data suggest that AER-270/271 treatment results in altered S1PR1 transcription thus changing T cell trafficking and prolonging allograft survival. Therefore, AQP4 blockade may be an attractive therapeutic strategy in transplantation and other immune-mediated diseases.
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Liu, Yiwen. "At a Moment’s Notice: Indonesian Maids Write on Their Lives Abroad, Jafar Suryomenggolo (ed. and trans.) (2019)." Transitions: Journal of Transient Migration 5, no. 1 (March 1, 2021): 77–79. http://dx.doi.org/10.1386/tjtm_00032_5.
Повний текст джерелаАнотація:
Review of: At a Moment’s Notice: Indonesian Maids Write on Their Lives Abroad, Jafar Suryomenggolo (ed. and trans.) (2019) Copenhagen: NIAS Press, 219 pp., ISBN 978-8-77694-270-0, h/bk, £65.00; ISBN 978-8-77694-271-7, p/bk, £19.99
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Ely-Harper, Kerreen. "Playfulness in Shakespearean Adaptations, Marina Gerzic and Aidan Norrie (eds) (2020)." Australasian Journal of Popular Culture 11, no. 1 (December 1, 2022): 205–6. http://dx.doi.org/10.1386/ajpc_00062_5.
Повний текст джерелаАнотація:
Review of: Playfulness in Shakespearean Adaptations, Marina Gerzic and Aidan Norrie (eds) (2020) Abingdon: Routledge, 270 pp., ISBN 978-0-36725-646-3, h/bk, AUD 273 ISBN 978-0-36750-464-9, p/bk, AUD 77.99 ISBN 978-0-42928-880-7, e-book, AUD 62.09
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Predieri, S., D. T. Krizek, R. M. Mirecki, H. A. Norman, and R. H. Zimmerman. "646 (PS 4) PHOTOSYNTHETIC PHOTON FLUX AND UV-B EFFECTS ON ETHYLENE EVOLUTION, PROLIFERATION, AND LIPID CONTENT OF `DOYENNE D'HIVER' PEAR IN VITRO." HortScience 28, no. 5 (May 1993): 543g—544. http://dx.doi.org/10.21273/hortsci.28.5.543g.
Повний текст джерелаАнотація:
In vitro-grown shoots of `Doyenne d'Hiver' pear (Pyrus communis L.) were maintained for 7 days on 16-h photoperiods at photosynthetic photon fluxes (PPF) of 90, 180 or 270 μmol·m-2·s-1 and irradiated 6 h per day midway through the photoperiod at 0.2 (-UV-B) or 12.0 (+UV-B) kJ·m-2·d-1 of biologically effective ultraviolet-B (UV-BBE) radiation. Increased ethylene production from UV-BBE-treated shoots as compared to the control was recorded after 24 h in cultures grown under 90 and 180 μmol·m-2·s-1 and after 72 h in shoots grown under 270 μmol·m-2·s-1; PPF level had little effect on amount of ethylene evolved. Proliferation was highest at 270 μmol·m-2·s-1, but UV-BBE decreased proliferation and increased apical necrosis. UV-BBE treatment increased lipid peroxidation after 24 h based on malondialdehyde (MDA) determination, but thereafter had no consistent effect on MDA. UV-BBE exposure slightly decreased the monogalactosyldiacylglycerol/digalactosyldiacylglycerol ratio during the initial 24 h, showing an effect on chloroplast membranes.
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Chouqar, J., Z. Benkhaldoun, A. Jabiri, J. Lustig-Yaeger, A. Soubkiou, and A. Szentgyorgyi. "Properties of sub-Neptune atmospheres: TOI-270 system." Monthly Notices of the Royal Astronomical Society 495, no. 1 (May 2, 2020): 962–70. http://dx.doi.org/10.1093/mnras/staa1198.
Повний текст джерелаАнотація:
ABSTRACT We investigate the potential for the James Webb Space Telescope (JWST) to detect and characterize the atmospheres of the sub-Neptunian exoplanets in the TOI-270 system. Sub-Neptunes are considered more likely to be water worlds than gas dwarfs. We model their atmospheres using three atmospheric compositions – two examples of hydrogen-dominated atmospheres and a water-dominated atmosphere. We then simulate the infrared transmission spectra of these atmospheres for JWST instrument modes optimized for transit observation of exoplanet atmospheres: NIRISS, NIRSpec, and MIRI. We then predict the observability of each exoplanet’s atmosphere. TOI-270c and d are excellent targets for detecting atmospheres with JWST transmission spectroscopy, requiring only 1 transit observation with NIRISS, NIRSpec, and MIRI; higher signal-to-noise ratio can be obtained for a clear H-rich atmosphere. Fewer than three transits with NIRISS and NIRSpec may be enough to reveal molecular features. Water-dominated atmospheres require more transits. Water spectral features in water-dominated atmospheres may be detectable with NIRISS in two or three transits. We find that the detection of spectral features in a cloudy, H-rich atmosphere does not require integrations as long as those required for the water-dominated atmosphere, which is consistent with the differences in atmospheric mean molecular weight. TOI-270c and d could be prime targets for JWST transit observations of sub-Neptune atmospheres. These results provide useful predictions for observers who may propose to use JWST to detect and characterize the TOI-270 planet atmospheres.
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JANEK, M., T. SAITO, V. P. LADYGIN, M. HATANO, A. YU. ISUPOV, H. KATO, N. B. LADYGINA, et al. "MEASUREMENTS OF THE TENSOR AND VECTOR ANALYZING POWERS FOR THE d+d→3H+p AND d+d→3He+n REACTIONS AT 270 MeV." International Journal of Modern Physics A 20, no. 02n03 (January 30, 2005): 646–48. http://dx.doi.org/10.1142/s0217751x05022044.
Повний текст джерелаАнотація:
The experiment with polarized deuteron beam was performed at energies 140, 200 and 270 MeV at RIKEN, Japan, in December 2000. The high-momentum structure of the 3 He , 3 H and deuteron was investigated. For this purpose the angular dependence of the tensor and vector analyzing powers were measured for the reactions d + d →3 H + p and d + d →3 He + n . In this report the results on the tensor Axx, Ayy and vector Ay analyzing powers at 270 MeV are presented.
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Sosa, Silvio, Marco Pelin, Cristina Ponti, Michela Carlin, and Aurelia Tubaro. "Acute Toxicity by Oral Co-Exposure to Palytoxin and Okadaic Acid in Mice." Marine Drugs 20, no. 12 (November 24, 2022): 735. http://dx.doi.org/10.3390/md20120735.
Повний текст джерелаАнотація:
The frequent occurrence of marine dinoflagellates producing palytoxin (PLTX) or okadaic acid (OA) raises concern for the possible co-presence of these toxins in seafood, leading to additive or synergistic adverse effects in consumers. Thus, the acute oral toxicity of PLTX and OA association was evaluated in mice: groups of eight female CD-1 mice were administered by gavage with combined doses of PLTX (30, 90 or 270 μg/kg) and OA (370 μg/kg), or with each individual toxin, recording signs up to 24 h (five mice) and 14 days (three mice). Lethal effects occurred only after PLTX (90 or 270 μg/kg) exposure, alone or combined with OA, also during the 14-day recovery. PLTX induced scratching, piloerection, abdominal swelling, muscle spasms, paralysis and dyspnea, which increased in frequency or duration when co-administered with OA. The latter induced only diarrhea. At 24 h, PLTX (90 or 270 μg/kg) and OA caused wall redness in the small intestine or pale fluid accumulation in its lumen, respectively. These effects co-occurred in mice co-exposed to PLTX (90 or 270 μg/kg) and OA, and were associated with slight ulcers and inflammation at forestomach. PLTX (270 μg/kg alone or 90 μg/kg associated with OA) also decreased the liver/body weight ratio, reducing hepatocyte glycogen (270 μg/kg, alone or combined with OA). No alterations were recorded in surviving mice after 14 days. Overall, the study suggests additive effects of PLTX and OA that should be considered for their risk assessment as seafood contaminants.
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M. Hussain, Halah, and Abdulhaleem A.K. Mohammed. "Experimental Study of Iraqi Light Naphtha Isomerization over Ni-Pt/H-Mordenite." Iraqi Journal of Chemical and Petroleum Engineering 20, no. 4 (December 30, 2019): 61–66. http://dx.doi.org/10.31699/ijcpe.2019.4.10.
Повний текст джерелаАнотація:
Hydroisomerization of Iraqi light naphtha was studied on prepared Ni-Pt/H-mordenite catalyst at a temperature range of 220-300°C, hydrogen to hydrocarbon molar ratio of 3.7, liquid hourly space velocity (LHSV) 1 hr-1 and at atmospheric pressure.
The result shows that the hydrisomerization of light naphtha increases with the increase in reaction temperature at constant LHSV. However, above 270 0C the isomers formation decreases and the reaction is shifted towards the hydrocracking reaction, a higher octane number of naphtha was formed at 270 °C.
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Snazell, James. "Experimental Film and Photochemical Practices, Kim Knowles (2020)." Moving Image Review & Art Journal (MIRAJ) 10, no. 1 (September 1, 2021): 228–34. http://dx.doi.org/10.1386/miraj_00077_5.
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Wu, Jianghong, Li Qin, Conghui Wang, Baoliang Lv, Liancheng Wang, Jiangang Chen, and Yao Xu. "Ultrathin N-rich boron nitride nanosheets supported iron catalyst for Fischer–Tropsch synthesis." RSC Advances 6, no. 44 (2016): 38356–64. http://dx.doi.org/10.1039/c6ra05517f.
Повний текст джерелаДисертації з теми "H-270"
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Guedes, Danusa. "Estrat?gias de forrageio em micos-estrela (Callithrix penicillata) : os micos usam jogos durante o forrageio social?" Pontif?cia Universidade Cat?lica do Rio Grande do Sul, 2012. http://tede2.pucrs.br/tede2/handle/tede/270.
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Previous issue date: 2012-11-09Anthropoid primates stand out among mammals because of their advanced cognitive skills resulting from the evolution of a relatively larger brain. Their ability to use social tactics to solve ecological and group-living challenges has been proposed by some experts as the major selective pressure that drove their brain evolution and increase in cognitive skills. Yet, little is known about how differences in social intelligence affect individual fitness within primate groups, including those of New World species. Previous studies have shown that tamarins (Saguinus) and capuchin monkeys (Sapajus) integrate ecological and social information in their group foraging decision-making, thereby suggesting that they adopt efficient cognitive mechanisms for coping with the social network. However, these studies did not analyze individual behavior from a Game Theory perspective, which provides an appropriate theoretical framework for evaluating individual decisions within a social context. In this research we tested whether black tufted-ear marmosets (Callithrix penicillata) are capable of integrating social and ecological information for making economical foraging decisions as predicted by the Producer-Scrounger Game. Specifically, we tested whether the members of social groups adjust their foraging strategies (producer and scrounger) in response to changes in the productivity and density of food resources and whether the individual choice of strategy and foraging success are age-sex and social rank dependent. The study was conducted with two wild groups living in a forest fragment at Fazenda Cauaia, Matozinhos, State of Minas Gerais, Brazil, from October 2009 to October 2011. The experimental design involved the establishment of two feeding stations (one in the home range of each group) composed of five platforms in a circular arrangement. The behavior of the marmosets, including the amount of food reward (arabic gum) eaten by each individual, was recorded with a closed-circuit television (CCTV). We ran four experiments controlling the amount of food available in the station (productivity) and the number of rewarded feeding apparatuses (density). The experimental conditions were: low density-low productivity, low density-high productivity, high density-low productivity and high density-high productivity. Individuals differed in their investment in producing resources (that is, searching for food rewards in platforms) in both groups throughout the study, indicating the use of the Producer-Scrounger Game. As predicted by this model, the finder s advantage (amount of food eaten by the producer of a resource before the arrival of scroungers), the foraging success of producers and the proportion of individuals playing producer in the group were higher under conditions of low productivity. Changes in resource density also influenced the proportion of individuals adopting each strategy. Again, more individuals played producer under conditions of low resource density. The latency to the arrival of the first scrounger was lower under conditions of low density and low productivity. Adult males also tended to play scrounger more often than adult females under these circumstances. Social rank did not have a significant relationship with individual foraging strategy and success. We conclude that black tufted-ear marmosets use ecological and social information to make foraging decisions within their groups and suggest that the strategy to be played is chosen by the individual prior to the arrival of the group at the food patch. Finally, we confirmed that the Game Theory and the Producer-Scrounger model are useful theoretical frameworks for analyzing the individual foraging decisions of black tufted-ear marmosets within a social context
Os primatas antrop?ides destacam-se dentre os mam?feros por sua elevada capacidade cognitiva decorrente da evolu??o de um c?rebro relativamente maior. A habilidade em usar t?ticas sociais para resolver problemas ecol?gicos e da vida em grupo tem sido apontada por alguns especialistas como a maior press?o seletiva que direcionou a evolu??o do c?rebro e o aumento da capacidade cognitiva nestes primatas. Contudo, pouco se sabe sobre a influ?ncia da intelig?ncia social no fitness dos primatas, incluindo as esp?cies neotropicais. Estudos pr?vios fornecem evid?ncias de que os primatas dos g?neros Saguinus (soins) e Sapajus (macacos-prego) podem integrar informa??es ecol?gicas e sociais na tomada de decis?es durante o forrageio em grupo, sugerindo que estes primatas possuem mecanismos cognitivos eficientes para lidar com a rede social. No entanto, estes estudos n?o utilizaram a perspectiva da Teoria dos Jogos, a qual fornece o arcabou?o te?rico adequado para explorar decis?es individuais num contexto social. Nesta pesquisa testamos se os micos-estrela (Callithrix penicillata) s?o capazes de integrar informa??es sociais e ecol?gicas para tomar decis?es econ?micas de forrageio como predito pelo modelo do Jogo Produtor-Usurpador. Testamos, especificamente, se os membros de grupos sociais ajustam suas estrat?gias de forrageio (produtor e usurpador) em resposta a mudan?as na produtividade e densidade de recursos alimentares e se a classe sexo-et?ria e a posi??o hier?rquica influenciam a escolha da estrat?gia individual e o sucesso na obten??o de alimento. O estudo foi realizado com dois grupos de vida livre em um fragmento florestal na Fazenda Cauaia, Matozinhos, Minas Gerais, no per?odo de outubro de 2009 a outubro de 2011. O desenho experimental envolveu a constru??o de duas esta??es de alimenta??o, uma para cada grupo, com cinco plataformas dispostas em c?rculo. O comportamento dos animais, incluindo a quantidade de recompensa alimentar (goma ar?bica) ingerida por cada membro, foi registrado por grava??es com um circuito fechado de televis?o (CFTV). Foram conduzidos quatro experimentos, nos quais foram controlados a quantidade de alimento dispon?vel na esta??o (produtividade) e o n?mero de aparatos com recompensa alimentar (densidade). As condi??es experimentais foram: baixa densidade-baixa produtividade, baixa densidade-alta produtividade, alta densidade-baixa produtividade e alta densidade-alta produtividade. Ao longo do estudo foram observadas diferen?as individuais no investimento dos micos-estrela de cada grupo na produ??o de recursos (ou seja, na busca pelas recompensas alimentares nas plataformas), indicando o uso do Jogo Produtor-Usurpador. Conforme previsto por este modelo, a vantagem do produtor (quantidade de alimento ingerida antes da chegada dos usurpadores), o sucesso de forrageio dos produtores e a propor??o de produtores foi maior sob condi??es de baixa produtividade. A varia??o na densidade de recursos tamb?m afetou a propor??o de indiv?duos adotando cada estrat?gia nos grupos, sendo observado um maior n?mero de produtores sob condi??es de baixa densidade. A lat?ncia para a chegada do primeiro usurpador foi menor sob condi??es de baixa densidade e de baixa produtividade. Os machos adultos tamb?m adotaram mais a estrat?gia de usurpador do que as f?meas adultas sob estas condi??es. A posi??o hier?rquica n?o apresentou rela??o significativa com o sucesso e o investimento individual em determinada estrat?gia. ? poss?vel concluir que os micos-estrela usam informa??es ecol?gicas e sociais para tomar decis?es durante o forrageio social e sugerir que a estrat?gia ? escolhida antes dos indiv?duos chegarem ? mancha de alimenta??o. Por fim, confirmou-se que a Teoria dos Jogos e o modelo Produtor-Usurpador s?o ferramentas ?teis para avaliar as decis?es individuais dos micos-estrela num contexto social
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Hedderich, Dennis Martin [Verfasser], Jörg H. [Akademischer Betreuer] Kleeff, and Florian R. [Akademischer Betreuer] Greten. "Die klinische Bedeutung des costimulatorischen Liganden B7-H3 (CD 276) beim Pankreaskarzinom / Dennis Martin Hedderich. Gutachter: Jörg H. Kleeff ; Florian R. Greten. Betreuer: Jörg H. Kleeff." München : Universitätsbibliothek der TU München, 2012. http://d-nb.info/1031075992/34.
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Navarro, Hernández Ramiro Gabriel. "Diseño estructural de un apilador radial con capacidad para transportar 275 T/H de arena para concreto." Bachelor's thesis, Pontificia Universidad Católica del Perú, 2015. http://tesis.pucp.edu.pe/repositorio/handle/123456789/6455.
Повний текст джерелаАнотація:
Durante los últimos años, debido a la gran cantidad de edificaciones nuevas y obras
urbanas que se pudieron observar no sólo en la capital, sino en todo el país, es seguro
afirmar que el sector construcción ha encontrado una época de auge. Este incremento,
aunque ahora desacelerado –respaldado por cifras de PBI del sector económico en
cuestión–, trajo como consecuencia un aumento en el consumo del concreto. Este
material se encuentra compuesto, principalmente, de cemento, agua y agregados,
abarcando estos últimos un 82% del volumen total y aportando, de esta manera, una
gran cantidad de propiedades importantes al resultado. El problema que surgió a partir
de esta realidad es la necesidad de manejar de manera apropiada la demanda
incrementada de uno de los agregados más importantes: la arena fina.
Utilizando como información de entrada las propiedades físicas del material en mención,
dictados por las normas ASTM C33, y el volumen de producción de la cantera más
importante de este material en Lima –la de Jicamarca–, se tuvo como objetivo del
presente trabajo alcanzar, mediante la aplicación de conocimientos y criterio en
ingeniería mecánica adquiridos durante la carrera, un diseño estructural de un apilador
o “stacker” radial que sea óptimo no sólo en resistencia, rigidez y estabilidad, sino
también en funcionalidad y economía.
El objetivo se alcanzó mediante el análisis y descarte de alternativas, utilizando cálculos
de resistencia, rigidez y estabilidad, previa estimación de un sistema de faja
transportadora que sería cargado por la armadura. Para esto, se empleó como base la
norma ISO 5049 para el diseño de estructuras metálicas de equipos móviles para el
manejo continuo de materiales a granel, el manual de construcción en acero de la AISC
y bibliografía complementaria de diseño. Por último, se aproximaron los costos de las
opciones en carrera con motivo de poder seleccionar la alternativa más viable.
El resultado final fue el diseño general de una estructura de acero principalmente tubular
con una viga principal de celosía que, mediante el cumplimiento de criterios normados
de resistencia, rigidez y estabilidad, así como de economía en el suministro y
fabricación, se encuentra en la capacidad de manejar el apilamiento radial al aire libre
de un volumen de producción significativo de arena.Tesis
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Elias, Gwenno Angharad. "Golygiad ac astudiaeth destunol o'r llyfr cyfraith yn LIGC, llawysgrif Peniarth 164 (H), ynghyd a'r copiau ohoni yn llawysgrifau Peniarth 278 a Llanstephan 121." Thesis, Bangor University, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.495758.
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MOREL, GILDAS. "Instabilite lombaire douloureuse : traitement par stabilisation souple postero-laterale (systeme du docteur h. graf) ; a propos de 27 cas." Rennes 1, 1992. http://www.theses.fr/1992REN1M090.
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MARTINOT, JEAN-CHRISTOPHE. "Mortalite post operatoire d'un service de chirurgie generale de c. H. U. : annee 1990, 1492 operes, 27 deces post operatoires." Lille 2, 1991. http://www.theses.fr/1991LIL2M069.
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Zimny, Katja [Verfasser], and Jürgen H. [Akademischer Betreuer] Dolderer. "Scapholunäre Achsenmethode (SLAM) zur Rekonstruktion von dynamischen SL-Bandläsionen am Handgelenk im Vergleich zu bisherigen Standardverfahren - eine klinische Studie an 27 Patienten / Katja Zimny ; Betreuer: Jürgen H. Dolderer." Regensburg : Universitätsbibliothek Regensburg, 2019. http://d-nb.info/1201884306/34.
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Perot, Patrick. "Activité du service des admissions et urgences chirurgicales au C. H. R. U. De Caen : étude quantitative et qualitative (réalisée sur une période de quinze jours du 27/05/91 au 11/06/91)." Caen, 1993. http://www.theses.fr/1993CAEN3004.
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Brinkmeier, Michael. "On Operads." Doctoral thesis, 2001. https://repositorium.ub.uni-osnabrueck.de/handle/urn:nbn:de:gbv:700-2001051822.
Повний текст джерелаАнотація:
This Thesis consists of four independent parts. In the first part I prove that the delooping, i.e.the classifying space, of a grouplike monoid is an $H$-space if and only if its multiplication is a homotopy homomorphism. This is an extension and clarification of a result of Sugawara. Furthermore I prove that the Moore loop space functor and the construction of the classifying space induce an adjunction on the corresponding homotopy categories. In the second part I extend a result of G. Dunn, by proving that the tensorproduct $C_{n_1}\otimes\dots \otimes C_{n_j}$ of little cube operads is a topologically equivalent suboperad of $C_{n_1 \dots n_j}$. In the third part I describe operads as algebras over a certain colored operad. By application of results of Boardman and Vogt I describe a model of the homotopy category of topological operads and algebras over them, as well as a notion of lax operads, i.e. operads whose axioms are weakened up to coherent homotopies. Here the W-construction, a functorial cofibrant replacement for a topological operad, plays a central role. As one application I construct a model for the homotopy category of topological categories. C. Berger claimed to have constructed an operad structure on the permutohedras, whose associated monad is exactly the Milgram-construction of the free two-fold loop space. In the fourth part I prove that this statement is not correct.
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Manikandan, K. "Crystal Structures Of Native And Xylosaccharides-Bound Alkali Thermostable Xylanase From An Alkalophilic Bacillus SP. NG-27: Structural Insights Into Alkalophilicity. Analysis Of C-H...O Hydrogen Bonds In Helices Of Globular Proteins." Thesis, 2006. https://etd.iisc.ac.in/handle/2005/328.
Повний текст джерелаАнотація:
Xylanases are xylan-degrading enzymes, belong to glycosyl hydrolases (GH). Xylanases from the two major families 10 (GH10) and 11 (GH11) catalyze the hydrolysis of internal β-, bonds of xylan backbone. Xylan is the second most abundant polysaccharide in nature. Nearly one third of the dry weight of the higher plants is xylan and therefore, xylanases have an important role in biomass conversions. Currently, the most effective application of xylanases is in prebleaching of kraft pulp to minimize the use of environmentally hazardous chemicals in the subsequent treatment stages. In recent years, therefore, attention is focused on to isolate and/or engineer the xylanases for the industrial requirements. The desirable roperties of xylanases in paper industry are stability and activity at high temperatures and alkaline pH. While he factors responsible for the thermal stability of GH10 xylanases have been analyzed, factors governing the alkaline stability of GH10 xylanases remain poorly understood.
The present thesis reports the crystal structures of an alkali thermostable GH10 extracellular endo-xylanase (BSX) from an alkalophilic organism, Bacillus sp. NG-27 in free and xylosaccharides-bound form. The enzyme was purified from the native organism and crystallized. The structure was solved by molecular replacement method. The 2.2 Å crystal structure of the native BSX enzyme is the first structure of an alkali thermostable GH10 family xylanase from an alkalophilic organism. It has unveiled unique protein properties that can form the basis for improving the thermal, alkaline stability and activity by site directed mutagenesis. The comparative study, especially in relation to GH10 xylanases, deciphered important structural features which are likely to be responsible for the alkaline stability of the enzyme. The work exemplifies the mechanism of adaptation of enzymes to function under polyextreme conditions through changes in the nature and composition of solvent-exposed residues. As apparent from the comparative study, the enhanced stability of the protein can be attributed to the surface rich in acidic residues and less number of solvent-exposed Asn as seen in BSX. This situation which may be roughly described as “acidic residues outside and Asn inside”, is a notable feature of alkali-stable GH10 xylanases from alkalophilic organisms.
In addition, the candidate has carried out the comprehensive database analysis of the occurrence of C-H…O hydrogen bonds in helices and helix termini of globular proteins. The study provides a compelling evidence that the main-chain Cα and the side-chains CH which participate in C-H…O hydrogen bonds collectively augment the cohesive energy and thereby contribute together with the classical N-H…O hydrogen bonds and other interactions to the overall stability of helix and therefore of proteins.
Chapter 1 starts with a brief introduction of xylanases, their classifications and overall folds. At present, a little more than a dozen of crystal structures of GH10 xylanases are known and described in the literature. A brief mention about these structures and their optimum pH and temperature is outlined under a separate section. In view of the industrial importance of the study enzyme, the potential industrial and biotechnological applications of xylanases are detailed in this Chapter. A section is dedicated to describe the present study enzyme BSX, an alkali thermostable endo-xylanase from an alkalophilic bacterium, Bacillus sp. NG-27. BSX has a molecular mass of ~41 kDa and is optimally active at 343 K and at a pH of 8.4. The alkaline thermostability of the wild type BSX is likely to be industrially important. At the end, the scope of the present work is detailed.
Chapter 2 presents the purification of xylanase (BSX) from Bacillus sp. NG-27, the crystallization of the native and xylosaccharides-bound BSX, the X-ray diffraction data collection on these crystals and processing of the data. Repeated attempts to crystallize the protein expressed in the chloroplast of transgenic tobacco plant were unsuccessful. However, crystallization was achieved with the protein sample purified from the native source by hanging drop vapour diffusion method. Crystals were grown at both acidic (4.6) and basic pH (8.5). The corresponding crystallization conditions are 0.2 M MgCl2, 0.1 M sodium acetate pH 4.6 and 20% PEG 550 MME and 0.1 M aCl, 0.01 M MgCl2, 0.1 M Tris-HCl pH 8.5 and 15% PEG 8000. Crystals grown at acidic pH were not suitable for X-ray diffraction study. Subsequently, crystal obtained at a basic pH of 8.5 was used for X-ray data collection and it diffracted X-rays to better than 2.2 Å at the home source at cryo-temperature (100 K). Native BSX crystals belong to monoclinic space group C2 with unit cell parameters a = 174.5 Å, b = 54.7 Å, c = 131.5 Å and β = 131.2°. Crystals of xylosaccharides-bound enzyme were grown in a slightly modified crystallization condition of native, 0.1 M NaCl, 0.2 M MgCl2, 0.1 M Tris-HCl pH 8.5 and 15% PEG 8000 and the enzyme was incubated with xylan prior to setting up the crystallization. Crystals belong to primitive orthorhombic space group P212121 with unit cell parameters a = 59.2 Å, b = 83.8 Å and c = 174.4 Å. A data set was collected using synchrotron radiation of wave length 1.0 Å from a cryo-cooled crystal at Spring-8 BL26B1 beam line, Japan. The Matthews coefficient VM for native and xylosaccharides- bound crystals was calculated to be 2.8 and 2.7 Å3 Da-1, respectively, suggesting two molecules in each crystal asymmetric unit. No twinning was detected in both the datasets and the overall quality of the data sets was found to be good.
Chapter 3 details the application of molecular replacement method to the structure solution of native and xylosaccharides-bound BSX, the course of iterative model building and the refinement carried out, and the quality of the final protein structure models. The native-enzyme structure solution was obtained by the molecular replacement method using as a search model the crystal structure (PDB code 1hiz) of the closest homologous, extracellular xylanase (GSX) from Geobacillus stearothermophilus. No non- crystallographic symmetry (NCS) restraint was applied between the two independent molecules in the crystal asymmetric unit at the final round of refinement. The final positional refinement of native BSX converged to R factors of R = 19.4% and Rfree = 23.5% for data between 20.0 to 2.2 Å. The final native model consists of 5704 protein atoms, two Mg2+ ions and 721 solvent water molecules. The final native model was taken as the search structure for the xylosaccharides-bound BSX and a solution with a correlation coefficient of 70.7% and an R-factor of 32.1% was obtained from the molecular replacement calculation. Unlike the native structure refinement, NCS restraint was imposed at all stages of the refinement. Bound xylosaccharides were clearly visible inthe difference Fourier electron density maps. The last round of refinement gave a model with R and Rfree of 21.8% and 25.7%, respectively. The final xylosaccharides-bound model consists of 5766 protein atoms, four Mg2+ ions, 85 atoms belong to bound xylosaccharides and 523 solvent water molecules. No residues were found in the disallowed region of the Ramachandran (φ, ψ) map for both the structures.
Chapter 4 describes the native and xylosaccharides-bound BSX crystal structures and the structural comparison of BSX with other GH10 family xylanase crystal structures for which the optimum temperature and pH are known in the literature. BSX folds as the ubiquitous (β/α)8-barrel, a common structural superfold characteristic of GH10 xylanases. The two active site glutamic acid residues, Glu149 and Glu259, are located on opposite sides of the active site cleft and their side-chains are at a distance of 5.5 Å apart suggesting the enzymatic reaction takes place by the retaining mechanism. From the structural superposition of other xylotriose-bound xylanase structures on to the xylosaccharides-bound BSX, structural plasticity in the xylotriose binding can be inferred, implying that the xylose recognition at the subsite -3 displays plasticity and is less specific as opposed to that at -1 and -2 subsites. The stacking interaction of one of the xylose moieties of the xylobiose with the Trp235 seen in BSX provides, for the first time, a structural evidence for the direct involvement of Trp235 in xylosaccharides binding.
The crystal structure revealed a metal binding site, found at the C-terminal end of catalytic domain. The presence of metal binding site was not anticipated from earlier theoretically modeled structure and biochemical studies. Further, we have shown experimentally the requirement of Mg2+ ion for the enzyme activity. We havedescribed a novel WP sequence-structure-interaction motif which is present in the (+) side of the active site region and presumably helps in the efficient binding of the carbohydrate moiety of the xylan in the active site cleft of BSX.
The structural comparison of BSX with other GH10 xylanases solved to date and characterized to be active at a pH close to neutral was done for the first time. The comparative study revealed the essential structural features which may responsible for the alkaline stability of GH10 xylanases.Briefly, the alkalophilic GH10 xylanases from alkalophilic organisms have surface abundant in acidic residues, the heat and alkaline susceptible residue Asn depleted on the protein surface and increased number of salt bridges.
Our study has unveiled the role of the nature and composition of protein surface amino acids in the adaptation of enzymes to polyextreme conditions. The observations reported in the thesis provide important lessons for engineering alkaline stability in xylanases for industrial applications and in general for the understanding of alkaline stability in related proteins.
A comparison of the surface features of the BSX and of halophilic proteins allowed us to predict the activity of BSX at high salt concentrations, which we verified through experiments. This offered us important lessons in polyextremophilicity of proteins, where understanding structural features of a protein stable in one set of extreme conditions provided clues about the activity of the protein in other extreme conditions.
Chapter 5 summaries the important findings of the present study from the crystal structural analysis of BSX and its comparison with non-alkalophilic GH10 xylanases. Separate sections are made on conclusions and future prospects for the study on BSX.
Chapter 6 describes the comprehensive database analysis of C-H…O hydrogen bond in helices of globular proteins. The C-H…O hydrogen bonds found in helices are predominantly of type 5 → 1 or 4 → 1.Our analysis reveals that the Cγ and Cβ hydrogen atom(s) are frequently involved in such hydrogen bonds. A marked preference is noticed for aliphatic β-branched residue Ile to participate in 5 → 1 C- H…O hydrogen bonds involving methylene Cγ1 atom as donor in α-helices. In addition, C-H…O hydrogen bonds are present along with helix stabilizing salt bridges and to some extent compensate for the side-chain conformational entropy loss. Our analysis highlights that a multitude of local C-H…O hydrogen bondsformed by a variety of amino acid side-chains and Cα hydrogen atoms occur in helices and more so at the helix termini.
A majority of the helix favouring residues, Met, Glu, Arg, Lys, Leu and Gln which also have large side-chains with more donatable CH groups, have significant propensity to form side-chain to main-chain C-H…O hydrogen bonds in helix. The large side-chains are marked by their ability to shield from the solvent the polar atoms of the peptide backbone and at the same time participate in weak cohesive C-H…O interactions in the helix. This chapter also details the identification for the first time a novel chain reversal motif stabilized by 1 → 5 Cα-H…O interactions. The importance of these hydrogen bonds with respect to helix stability is discussed in the final section of the chapter.
Appendix A details the crystallographic and structural analyses oftwares used for the present thesis work.
Appendix B describes, in addition to the crystal structure analysis of BSX, the work carried out by the candidate on a comparative study of a thermostable xylanase from Thermoascus aurantiacus, solved in our laboratory at atomic 1.11 Å (293 K) and ultrahigh 0.89 Å (100 K) resolutions. From the comparison, we have for the first time pointed out the possibility of plasticity of ion pairs in proteins with water molecules mediating some of the alternate arrangements. The αβ-loops are relatively less flexible than the βα-loops. The β-strands are least affected structurally with the increase in temperature. Thus the TIM barrel fold in the study enzyme, though having a single domain, may be dissected into parts based on the relative flexibility and described as having a rigid core constituted by the β-barrel and a less rigid exterior formed by the surrounding α-helices.
Appendix C presents the crystallization and the preliminary X-ray characterization work done by the author of the thesis on an alkali thermostable cellulase enzyme from Thermomonospora sp. The protein is an extracellular enzyme with molecular mass of 14.2 kDa and interestingly, has the dual activity for both cellulose and xylan. The primary structure of the enzyme is not known. The enzyme was purified from the source organism and crystallized. A complete diffraction data set was collected and processed to 2.3 Å in an orthorhombic space group P212121.
Appendix D contains tables which give details about the analysed 5 → 1 Cα- H…O hydrogen bonds in helices and a novel chain reversal motif with 1 → 5 Cα-H…O hydrogen bonds.
Appendix E encloses reprints of publications which have resulted from the work reported in the thesis.
Книги з теми "H-270"
1
Rules, United States Congress House Committee on. Providing for the consideration of H.R. 2459: Report (to accompany H. Res. 270). [Washington, D.C.?: U.S. G.P.O., 1989.
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2
United States. Congress. House. Committee on Rules. Providing for the consideration of S. 1745: Report (to accompany H. Res. 270). [Washington, D.C.?: U.S. G.P.O., 1991.
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3
United States. Congress. House. Committee on Rules. Providing for the consideration of H.R. 2459: Report (to accompany H. Res. 270). [Washington, D.C.?: U.S. G.P.O., 1989.
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4
United States. Congress. House. Committee on Rules. Providing for the consideration of House Joint Resolution 362: Report (to accompany H. Res. 270). [Washington, D.C.?: U.S. G.P.O., 1987.
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5
United States. Congress. House. Committee on Rules. Providing for the consideration of House Joint Resolution 362: Report (to accompany H. Res. 270). [Washington, D.C.?: U.S. G.P.O., 1987.
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6
United States. Congress. House. Committee on Rules. Providing for consideration of H.R. 3090, Economic Security and Recovery Act of 2001: Report (to accompany H. Res. 270). Washington, D.C.]: [U.S. G.P.O.], 2001.
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7
Rules, United States Congress House Committee on. Providing for the consideration of H.R. 2247, the Amtrak Reform and Privatization Act of 1997: Report (to accompany H. Res. 270). [Washington, D.C.?: U.S. G.P.O., 1997.
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8
United States. Congress. House. Committee on Rules. Providing for the consideration of H.R. 2247, the Amtrak Reform and Privatization Act of 1997: Report (to accompany H. Res. 270). [Washington, D.C.?: U.S. G.P.O., 1997.
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9
Rules, United States Congress House Committee on. Providing for the consideration of House Joint Resolution 122, further continuing appropriations for fiscal year 1996: Report (to accompany H. Res. 270). [Washington, D.C.?: U.S. G.P.O., 1995.
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10
Rules, United States Congress House Committee on. Relating to consideration of the Senate amendments to H.R. 1308, Tax Relief, Simplification, and Equity Act of 2003: Report (to accompany H. Res. 270). [Washington, D.C: U.S. G.P.O., 2003.
Знайти повний текст джерелаЧастини книг з теми "H-270"
1
Pelletier-De Koninck, Jean-Christophe, Andreas Athienitis, and Hervé Frank Nouanegue. "Design of Photovoltaic/Thermal Collectors with Thermal Storage and Batteries to Enhance Building Performance and Resilience in Cold Climate." In Lecture Notes in Civil Engineering, 197–206. Cham: Springer Nature Switzerland, 2024. http://dx.doi.org/10.1007/978-3-031-57800-7_18.
Повний текст джерелаАнотація:
AbstractThis study consists of a sensitivity analysis of photovoltaic/thermal (PV/T) collectors, liquid thermal storage, and battery systems applied for the offices of a school building near Montreal, Canada to enhance building performance and resiliency to power outages during winter operation. The analysis was applied for 3 days in January with mixed solar conditions by varying the sizing of each of the components to achieve at least 8 h of self-sufficiency, the average length of power outages. It was found the optimal sizing for the studied system, while minimizing component costs, is to dimensions PV/T collectors to meet the base heating load, while maximizing thermal storage, and diminishing battery capacity to meet the base heat pump electricity consumption. For the case study, the optimal configuration was 27 PV/T, a 908 L thermal storage tank, and 10 kWh of battery capacity, to consistently achieve over 8 h of self-sufficiency in mixed sunny and cloudy winter conditions.
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Kurth, Alexandra. "Bassam Tibi: Die fundamentalistische Herausforderung. Der Islam und die Weltpolitik, Verlag C. H. Beck: München 1992, 274 S." In Klassiker der Sozialwissenschaften, 388–91. Wiesbaden: Springer Fachmedien Wiesbaden, 2016. http://dx.doi.org/10.1007/978-3-658-13213-2_90.
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Parasuraman, Malathy, and Priyantha Weerasinghe. "Application of mutation breeding techniques in the development of green crop varieties in Sri Lanka: the way forward." In Mutation breeding, genetic diversity and crop adaptation to climate change, 76–82. Wallingford: CABI, 2021. http://dx.doi.org/10.1079/9781789249095.0008.
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Abstract The Department of Agriculture (DOA) in Sri Lanka initiated mutation breeding in the 1960s with the introduction of a cobalt-60 source. The first rice mutant variety, MI 273, was released for general cultivation in 1971. M1 273, derived from irradiation of the H-4 variety, was identified as a drought-tolerant variety. An indirect rice mutant variety, developed by crossing the short mutant line BW267-3 with a highly adaptable variety, was released as BW 372 in 2013. It is moderately tolerant to blast, bacterial leaf blight, brown plant hopper, gall midge and iron toxicity, and thus increases productivity to 3-4 t/ha on lands prone to iron toxicity. The most popular groundnut variety cultivated in the country, 'Tissa', is a mutant developed by irradiation with gamma-rays at 200 Gy. It showed attributes of high yield, medium maturity (90-100 days) and high oil content (42%). 'Tissa' presently covers 80% of the groundnut cultivated area in Sri Lanka. A sesame mutant line, derived from the variety MI-3 irradiated at 200 Gy with 60Co gamma-rays, was released as 'Malee' (ANK-S2) in 1993. It is a high-yielding variety (1.1-1.8 t/ha) resistant to Phytophthora blight. A cherry-type mutant tomato variety, developed by irradiation of seeds with gamma-rays (320 Gy), was released as 'Lanka Cherry' in 2010. Improved attributes are pear-shaped fruits and bacterial wilt resistance. Narrow genetic variability in many crops is a constraint to the development of new varieties adapted to the changing climate. Hence, the DOA is emphasizing integration of induced mutagenesis in conventional breeding programmes to develop resistant/tolerant varieties having high yield, quality and health-promoting functional properties in field and horticultural crops. The newly installed gamma irradiation chamber facilitates the creation of genetic variability in food crops, thus paving the way for the development of greener varieties.
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Lima, Ana Teresa Macas, Ida Maria Gieysztor Bertelsen, Lisbeth Mølgaard Ottosen, and Neil A. James. "The Effect of Fishing Nets Aging on Metal Uptake." In Marine Plastics: Innovative Solutions to Tackling Waste, 189–210. Cham: Springer Nature Switzerland, 2023. http://dx.doi.org/10.1007/978-3-031-31058-4_11.
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AbstractFishing nets are mainly constituted of Polyethylene (PE), Polyamide, Polyethylene terephthalate (PET), Polypropylene (PP), and Nylon. While new, these plastics exhibit pristine mechanical performance but lose it as they age. But what about their metal adsorptive performance? Literature finds that plastics like PET and PVC accumulate Al, Cr, Mg, Fe, Co, Ni, Zn, Cd, and Pb, even when exposed to very low concentrations. This is mainly true for aged PVC (Kedzierski et al. Adsorption/desorption of Micropollutants. Mar Pollut Bull. 127:684–694, 2018). In this study, we look at the effect of age on the properties of fishing nets, including their capacity to adsorb metals. Because fishnets are in great part constituted by PE, we used standardized PE pellets as our reference. In calorimeter signaling, we observed that end-of-life fishing nets display a very different differential scanning calorimetry (DSC) pattern; both new and old fishing nets are very different from standardized PE polymer. Preliminary results show that Cr, Cu, Pb, and Se adsorption onto fishing nets occurs in the first 10 min to 6 h of exposure (24 h for Se). The maximum uptake was registered at 11 mg Cr kg‒1, 38 mg Cu kg‒1, 27 mg Pb kg‒1, and 15 mg Se kg‒1. All these concentrations refer to old end-of-life PE fishing nets, where new, unused PE fishing nets adsorb 2–20 times less (Old in this chapter refers to used fishing nets. The term is not attempting to attribute a particular life span/age to the nets). A comparison to different EU directives that regulate metal content in plastics for different end-uses shows that the old end-of-life PE fishing nets, after exposure to heavy metals, do not meet the regulations for hazardous waste. We believe that Greenlandic old waste fishing nets can be used to clean the wastewater, or metal-contaminated water, in Greenland and eventually, the rest of the world.
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Gibbs, Paul. "The Marketingisation of Higher Education." In Evaluating Education: Normative Systems and Institutional Practices, 221–33. Singapore: Springer Singapore, 2020. http://dx.doi.org/10.1007/978-981-15-7598-3_13.
Повний текст джерелаАнотація:
AbstractThis chapter does not stress the marketisation of higher education rather focuses upon the way in which this is done; the marketingisation of higher education. I do not deny that widening access to skills that can fuel growth is a logical extension of a consumerist ideology. What follows acknowledges these structural changes and then focuses on how marketing is a consequence and reinforce of such structural change. Indeed there is a substantial literature which addresses it (e.g. Molesworth et al. Having, being and higher education: The marketization of the university and the transformation of the student into consumer. Teaching in Higher Education, 14(3), 277–287, 2009; Brown R, Carasso H, Everything for sale? The marketisation of UK higher education. Routledge, London, 2013). Nor does it support that marketingation has brought no or only limited contributions to higher education. The expansion of the privileges of higher education to the many from the few, the greater governance and transparency of the process and practices of higher education institutions in their compact with society and a clearer ways to evaluate these activities have, to varying degrees, enhanced higher education. These interventions have opened the market for world class universities (WCUs) allowing them global as well as local reach. Yet it is strange that these improvements are consequences of market interventions by Governments, by publishers in terms of league tables, and by employers in terms of preferred (mythical?) skill sets and not for educative purposes. The emergent practices encouraged by these interventions increase the influence of marketing and facilitate a metamorphosis of institutions from educational entities to market responsive service providers whose intent focuses on impact and enhanced return on capital. This leads WCUs into the endless and Sisyphusan striving, often devoid of any ultimate worthy end but ends which are an inevitable consequence of managing rapidly increasing competition and shifting demands effectively rather than educative priorities. The chapter describes and discusses the consequences.
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"Oxyquinoxalines (H 235, 270; E 78, 199)." In Chemistry of Heterocyclic Compounds: A Series Of Monographs, 189–239. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2004. http://dx.doi.org/10.1002/0471533408.ch4.
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Wordsworth, Dorothy. "270. D. W. to H. C. R." In The Letters of William and Dorothy Wordsworth, Vol. 4: The Later Years: Part I: 1821–1828 (Second Revised Edition), edited by Ernest De Selincourt and Alan G. Hill, 503–5. Oxford University Press, 2000. http://dx.doi.org/10.1093/oseo/instance.00083426.
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Boening, John. "MONTHLY REVIEW, 3rd ser. 6 (1827), 261–270. M/H No. 2691." In The Reception of Classical German Literature in England, 1760–1860, 241–45. Routledge, 2020. http://dx.doi.org/10.4324/9781003010517-34.
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"Kap. 9: Molekularelektronik und selbstorganisierende Monoschichten (SAMs)." In Von Aromaten und Heterocyclen zur Bio- und Nanotechnologie, 157–92. GNT-Verlag GmbH, 2023. http://dx.doi.org/10.47261/1551-9.
Повний текст джерелаАнотація:
9.1 Von der Mikroelektronik zur Molekularelektronik 9.1.1 Gründung und Ziele des SFB 329 „Physikalische und chemische Grundlagen der Molekularelektronik“ 9.1.2 Synthese und Energietransfereigenschaften endständig substituierter Polyene 9.1.3 Synthesen und Energietransfereigenschaften endständig substituierter Oligothiophene 9.1.4 Donor-Akzeptor substituierte Bithiophene – neue Farbstoffe mit ausgeprägter positiver Solvatochromie 9.1.5 „Schaltermoleküle“ für einen intramolekularen Elektronentransfer 9.2 Selbstorganisierende Monoschichten (SAMs) – Synthesen, Charakterisierung, „Superdielektrika“, Anwendungen in der Mikroelektronik 9.2.1 Self-Assembled Monolayers von Organosilanen auf oxidiertem Si(100) 9.2.2 Insolar – Hysolar – SFB 270: „Wasserstoff als Energieträger“ 9.2.3 SAMs auf wasserstoffterminiertem Silizium – Strukturierung von Si–H-Oberflächen 9.2.4 Herstellung und Charakterisierung von SAMs auf Gold 9.2.5 Anwendungen Phenoxy-terminierter SAMs als „Superdielektrika“ in der Mikroelektronik
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Kaafarani, Haytham M. A. "Reducing Mortality Among Bleeding Trauma Patients with Tranexamic Acid." In 50 Studies Every Intensivist Should Know, edited by Edward A. Bittner and Michael E. Hochman, 241–47. Oxford University Press, 2018. http://dx.doi.org/10.1093/med/9780190467654.003.0040.
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The CRASH-2 trial is a randomized controlled trial performed in more than 270 hospitals across the world and aimed at studying the impact of tranexamic acid (TXA), an anti-fibrinolytic agent, on mortality in trauma patients presenting with hemorrhagic shock. With more than 20,000 patients, CRASH-2 showed a small but statistically significant decrease in mortality from 16% to 14.5% (p < 0.05), without any increase in thromboembolic events, in patients who received TXA versus placebo. Subset analyses suggested that the benefit was only present if TXA was administered within 3 h from injury. Two main criticisms of the study are (1) TXA reduced mortality but not the number of blood products used or the percentage of patients who needed transfusion, raising questions regarding the mechanism by which the drug worked; (2) the conductance of the study in moderate- to low-income countries, limiting its generalizability to high-income countries with advanced trauma systems.
Тези доповідей конференцій з теми "H-270"
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Ando, Ken J., R. Bornfreund, C. Brazier, Roger Holcombe, Ichiro Kasai, Peter J. Love, and Michael S. Smith. "270 x 436 HgCdTe FPA module for the Rosetta VIRTIS-H and -M instruments." In International Symposium on Optical Science and Technology, edited by Marija Strojnik and Bjorn F. Andresen. SPIE, 2000. http://dx.doi.org/10.1117/12.406557.
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2
Lee, Yeongbin, Jin-sung Paik, Minho Kwak, Jinsun Yoo, Kyu Hong Kim, Dongho Lee, and Hyeok-Bin Kwon. "Analysis and Comparison of Experimental Results Both of Wind Tunnel Test and Running Test for HEMU-400X Pantograph." In 2012 Joint Rail Conference. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/jrc2012-74026.
Повний текст джерелаАнотація:
In this paper, experimental results both of wind tunnel test and running test for HEMU-400X pantograph were compared and were analyzed. In wind tunnel test, 1/4scale pantograph for HEMU-400X which is being developed for the maximum speed of 400km/h in Korea were tested to investigate the vertical lift force of pantograph at the operational speed of 250, 270, 300, 330, 360 and 400km/h using lift estimation from 1/4 scaled model results. In the running test of train, the contacting force of pantograph was measured to current operational speed of 300km/h. Finally, the results of vertical lift force of pantograph in wind tunnel test and contacting force for the running test were compared to analyze the aerodynamic characteristics of the pantograph for HEMU-400X.
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Jin, Fei. "Lancang River Railway Arch Bridge with stiffened skeleton of Concrete-filled Steel Tubes." In IABSE Conference, Kuala Lumpur 2018: Engineering the Developing World. Zurich, Switzerland: International Association for Bridge and Structural Engineering (IABSE), 2018. http://dx.doi.org/10.2749/kualalumpur.2018.0940.
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<p>The Lancang River railway arch bridge, a key project, is located on Dali~Ruili Railway with a design speed of 140 km/h. The bridge spans over the Lancang River, with the max slope angle of the mountain body on both sides of the river being more than 80 degrees. The distance between the bridge deck and the river surface exceeds 270 m. The whole bridge is 528.1 m long and the main span is 342 m. The x-style arch rib is a deck-type concrete-filled steel tube stiffened skeleton, which becomes the main arch structure of single-box single-cell box section after swing erection, by means of filling the inner space and covering the outer face with concrete.</p>
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Niemann, Michael U., Sesha S. Srinivasan, Ashok Kumar, Elias K. Stefanakos, D. Yogi Goswami, and Kimberly McGrath. "Processing Analysis of the Ternary LiNH2-MgH2-LiBH4 System for Hydrogen Storage." In ASME 2009 International Mechanical Engineering Congress and Exposition. ASMEDC, 2009. http://dx.doi.org/10.1115/imece2009-11520.
Повний текст джерелаАнотація:
The ternary LiNH2-MgH2-LiBH4 hydrogen storage system has been extensively studied by adopting various processing reaction pathways. The stoichiometric ratio of LiNH2:MgH2:LiBH4 is kept constant with a 2:1:1 molar ratio. All samples are prepared using solid-state mechano-chemical synthesis with a constant rotational speed, but with varying milling duration. All samples are intimate mixtures of Li-B-N-H and MgH2, with varying particle sizes. It is found that the samples with MgH2 particle sizes of approximately 10nm exhibit lower initial hydrogen release at a temperature of 150°C. The as-synthesized hydrides exhibit two main hydrogen release temperatures, one around 160°C and the other around 300°C. The main hydrogen release temperature is reduced from 310°C to 270°C, while hydrogen is first reversibly released at temperatures as low as 150°C with a total hydrogen capacity of 6 wt.%.
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Vila, V., E. Reganon, J. Aznar, V. Lacueva, and M. Ruano. "EFFECT OF TREATMENT WITH STREPTOKINASE AND HEPARIN ON FIBRINOGEN, FIBRIN AND RELATED PROTEINS IN ACUIE MYOCARDIAL INFARCTION (/ME) PATIENTS." In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1644895.
Повний текст джерелаАнотація:
The properties of fibrinogen and fibrin, the levels of fibrincpeptide A (FPA) and fibrin(ogen) degradation products (FDP) were studied in 34 patients with AMI who were undergoing thrombolytic and heparin therapy. They were classified into 6 groups accordingto their stage of treatment: group 1, before intravenous administration of 800.000 U streptokinase over 30 min; group 2, after a<Mnistraticn of SK but before adninistraticn of heparin; group 3, during 24 h ofthe 5 ng/h heparin continuous infusion; group 4, during 48-72 h of the 16.6 ng/h heparin continuous infhsion; group 5, after 1 week of administration of SK and with a bolus inyection of 50 rg heparin every 4 h; group 6, patients who were undergoing only heparin treatment. The Fg 1/ Fg II ratio varies during treatment with SK and heparin. In group 1 a sligjnt increase (2.5) is observed. Group 2 shows a significantdecrease (0.6) as a result of fibrinolysis. In group3 the ratio reaches normal value (1.8) while in the fourth group it is twice the normal value (4). The value for group 5 is nearly normal (2.1), and in group 6 it reaches values similar to those obtained in group 4, which implies that the rise in the Fgl/Fgll ratio is not a result of fibrinolytic treatment. TheFPA level shows and increase in patients with AMI (group 1,126 ng/ml). When SK treatment is applied (group 2), FPA decreases to 52 ng/ml. Later treatment with heparin (group-3, 82; group-4, 44 and group-5, 81ng/ml) does not neutralize thrcmbinic activity. Patients treated only with heparin (group 6) show an FPAvalue of 19 ng/ml, which is lower than in the other groups. All of this indicates that thrombin is activated after fibrinolytic treatment. FDP values show asignificant increase in the six groups (1, 53; 2, 430; 3, 128; 4, 270; 5, 139 and 6, 141 ug/ml), which indicates that during treatment with heparin the fibrinolytic activity persists. he formation of highly cross-linked fibrin is altered in groups 1,2,3 and 4,as a consequence of circulating FDP effect and fibrincgeno- lysis.The permeability of the fibrin clotdecreases in groups 1 (0.42), 2 (1.3), 4 (1.1) and 5(0.5 ml/s/ng) and increases in group 2 (23.2 ml/s/nig) with respect to the normal plasma value (3.2 ml/s/nrg). The decrease in permeability must be related to the existence of hypercoagulability resistant to heparinization. FPA values, tine Fgl/Fgll ratio, andfibrin permeability can be used to evaluate the degree of thrcmbin activity during thrombolytic treatmentinAMI.
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Watson, J. H. P., D. C. Ellwood, and R. G. Lidzey. "Removal of Actinides and Other Radioactive Metal Ions From Water Systems." In ASME 2003 9th International Conference on Radioactive Waste Management and Environmental Remediation. ASMEDC, 2003. http://dx.doi.org/10.1115/icem2003-4909.
Повний текст джерелаАнотація:
In previous work the adsorption of a number of radioactive ions from solution by a strongly-magnetic iron sulfide material has been studied. The material was produced by sulfate-reducing bacteria in a novel bioreactor. The uptake is rapid and the loading on the adsorbent is high due to the high surface area of the adsorbent and because many of the ions are chemisorbed. Following the success of the biologically-generated material, Lidzey at Bio Separation Ltd was able to produce an iron sulfide material; studies at the University of Southampton reveal that it has the tochilinite structure which has similar adsorption properties for cations, but not anions, as the biologically-generated material but the Lidzey material is considerably cheaper to produce. Tochilinite is a layered metal hydroxide/sulfide composite. The composition of tochilinite ranges around 2Fe1-xS. {1.7Fe(OH)2}. In nature, these materials also have Mg0.7Al 0.3 replacing Fe in the hydroxide layer. By also precipitating magnetite, Fe3O4, together with the tochilinite Lidzey has made the adsorbent strongly magnetic. This paper presents individual results on the adsorption of 137Cs, 59Fe, 60Co, 106Ru, 110mAg, 51Cr, 54Mn, 203Hg, 109Cd, 90Sr, 239Pu and 241Am. Using 0.5g.l−l of the adsorbent the reduced the activity in solutions from 1190 Bq.ml−1 to <530 Bq.ml−1 after 1 h and to 340 Bq.ml−1 after 24 h. with 51Cr and 203Hg being responsible for 270 Bq.ml−1 of the total. For the decontamination of water streams containing dissolved radioactive isotopes the method proposed is to add the adsorbent and after a suitable residence time to extract the contaminated adsorbent using high gradient magnetic separation. In this method a slurry containing the particles to be separated are passed through a matrix of fine ferromagnetic wires magnetised to magnetic saturation by an externally applied magnetic field usually 5 Tesla. The particles to be separated are captured on the matrix, the decontaminated liquid passing through. The matrix is removed from the field and at the same time a clean matrix is inserted. The captured material recovered outside the magnetic field as a thick slurry and he cycle is repeated. These magnetic separation systems are in use throughout the world and will process up to 500m3.h−1.
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Akbari, M. H., S. A. Asaee, and R. Roohi. "Modeling of a Micro-Channel Water-Gas Shift Reactor." In ASME 2010 8th International Conference on Nanochannels, Microchannels, and Minichannels collocated with 3rd Joint US-European Fluids Engineering Summer Meeting. ASMEDC, 2010. http://dx.doi.org/10.1115/fedsm-icnmm2010-30241.
Повний текст джерелаАнотація:
Hydrogen purification through water-gas shift (WGS) is a favored option in fuel processing for hydrogen fuel cells. A three-dimensional single channel model is developed to simulate the behavior of a water-gas shift micro reactor. The flow regime is assumed to be steady and laminar; furthermore, it is presumed that the walls are isothermal. A water-gas shift reaction rate model is utilized to simulate the surface reaction on Pt/TiO2 catalyst. The gas feed composition is taken as the efflux of a typical auto-thermal reforming (ATR) reactor. A parametric study is conducted to investigate the effect of gas feed temperature, gas space velocity and channel length on water-gas shift micro reactor performance. The study resulted in an optimum water-gas shift micro reactor design. It should be noted that a water-gas shift micro reactor is an essential part of a reactor train to remove carbon monoxide from a hydrogen rich mixture. Such a mixture can be used as fuel for a PEM fuel cell in portable devices. The results of these simulations revealed that the optimum reactor consists of a square cross section channel with 100 μm hydraulic diameter, 20 mm length, space velocity of 1000 h−1 and gas feed temperature of 270°C. The carbon monoxide mole fraction in the efflux is in a range suitable for a typical preferential oxidation (PROX) reactor.
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Bonino, Christopher A., Joshua Hlebak, Nicholas Baldasaro, and Dennis Gilmore. "Pilot-Scale System With Particle-Based Heat Transfer Fluids for Concentrated Solar Power Applications." In ASME 2020 Power Conference collocated with the 2020 International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/power2020-16588.
Повний текст джерелаАнотація:
Abstract Concentrated solar power (CSP) is a promising large-scale, renewable power generation and energy storage technology, yet limited by the material properties of the heat transfer fluid. Current CSP plants use molten salts, which degrade above 600°C and freeze below 220°C. A dry, particle-based heat transfer fluid (pHTF) can operate up to and above 1,000°C, enabling high-efficiency power cycles, which may enhance CSP’s commercial competitiveness. Demonstration of the flow and heat-transfer performance of the pHTF in a scalable process is thereby critical to assess the feasibility for this technology. In this study, we report on a first-of-a-kind pilot system to evaluate heat transfer to/from a densely flowing pHTF. This process unit circulates the pHTF at flowrates up to 1 tonne/h. Thermal energy is transferred to the pHTF as it flows through an electrically heated pipe. A fluidization gas in the heated zone enhances the wall-to-pHTF heat transfer rate. We found that the introduction of gas mixtures with thermal conductivities 4.6 times greater than that of air led to a 65% increase in the heat transfer coefficient compared to fluidization by air alone. In addition to the fluidization gas, the particle size also plays a critical role in heat transfer performance. Particles with an average diameter of 270 μm contributed to heat transfer coefficients that were up to 25% greater than the performance of other particles of the same composition in size range of 65 to 350 μm. The considerations for the design of an on-sun system are also discussed. Moreover, the collective work demonstrates the promise of this unique design in solar applications.
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Sezgin, Jean-Gabriel, and Junichiro Yamabe. "Tensile and Fatigue Failure of 17-4 PH Martensitic Stainless Steels in Presence of Hydrogen Depending on Frequency and Heat Treatment." In ASME 2020 Pressure Vessels & Piping Conference. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/pvp2020-21122.
Повний текст джерелаАнотація:
Abstract Slow-strain-rate tensile (SSRT) and fatigue-life tests were carried out on 17-4PH martensitic stainless steel with an ultimate tensile strength (UTS) of ∼ 1 GPa. The specimens were precharged by exposure to hydrogen gas at pressures of 35 MPa or 100 MPa at 270°C for 200 h. The SSRT tests used smooth axisymmetric specimens made of two grades of 17-4PH (H1150 and H900) differing by the UTS due to their thermal history. No degradation of the UTS was observed for both H1150 and H900 grades. However, the relative reduction in area (RRA) was 0.31 for H1150 or 0.11 for H900, translating a difference in their hydrogen sensitivity. Both grades presented different fracture-surface morphologies: a mixture of quasi-cleavage (QC) and intergranular (IG) facets for H1150 and cleavage (C) facets for H900. Circumferentially-notched axisymmetric specimens made of H1150 were used for the fatigue-life tests in the [10−3 Hz;10 Hz] frequency range. Our previous study on low-alloy steels with UTS of around 950 MPa demonstrates that the fatigue life of a circumferentially-notched specimen with a sharp notch can be successfully predicted from the fatigue crack growth (FCG) property following the Paris law. This study used the same specimen geometry and a BCC steel with a similar UTS value; hence, the FCG behavior was investigated from the fatigue-life test of the notched specimen. As a result, the degradation of fatigue lives attributed to the FCG acceleration was observed in presence of hydrogen. A FCG acceleration ratio bounded to 30 was observed in the high-cycle regime, accompanied by QC facets. A FCG acceleration ratio bounded to ∼100 was observed in the low-cycle regime, accompanied by QC and IG facets. A FCG model accounting for the interaction of elementary mechanisms was proposed and succeeded in predicting the FCG acceleration ratio observed on H1150. This model was also successfully applied to a low-alloy steel with a comparable UTS (1002 MPa) tested in gaseous hydrogen.
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Bilik, Vladimir. "Automatic Measurement of Magnetron Rieke Diagrams." In Ampere 2019. Valencia: Universitat Politècnica de València, 2019. http://dx.doi.org/10.4995/ampere2019.2019.9782.
Повний текст джерелаАнотація:
A Rieke diagram [1] is a magnetron characteristic that visualizes the dependence of the generated frequency fg and the net delivered power PL on the load reflection coefficient GR. GR is defined in a specific magnetron-to-waveguide coupling structure called the standard or reference launcher (Fig. 1). The diagram is plotted as a family of isolines of constant fg and of constant PL in the polar diagram of GR. Rieke diagrams are essential in the design of applications without isolators, such as domestic or professional microwave ovens. Constructing Rieke diagrams is tedious, time-consuming and equipment-demanding [2], [3], preventing systematic studies of their dependence on operating conditions, such as anode voltage and its ripple, filament current, mounting repeatability, etc. We have devised a procedure, centering around a high-power automatic impedance matching device (autotuner), which enables fully automatic measurement and plotting of the stated dependences. A block diagram of the setup is shown in Fig. 1. The autotuner, when terminated in a match (waterload), can accomplish a task inverse to impedance matching: realizing any desired reflection coefficient GR. The measurement consists of stepping through a grid of n suitably chosen reflection coefficients GR = xR + jyR, covering a desired area of the polar diagram. Each GR is measured accurately by the autotuner, along with the corresponding fg and PL. Thus, raw data for constructing a Rieke diagram are obtained, the data consisting of a collection of n points {GR, fg, PL}i, i = 1…n, with GR, in general, irregularly scattered in the complex plane. A dedicated MATLAB routine then reads the data, sorts them out to create tabulated functions fg = f(xR, yR), PL = f(xR, yR), approximates these by a 2D spline, and uses the splines to plot smoothed isocontours for chosen constant values of fg and PL, completing thus the desired Rieke diagram construction. We will present details of this procedure as well as real-life examples. Fig. 1. Rieke diagram measurement setup. References Meredith, R. J., Engineers' Handbook of Industrial Microwave Heating, London: The IEE, 1998, 250–270. Takahashi, H., I. Namba, K. Akiyama, J. Microwave Power, 1979, 14, 261–267.Yixue, W., Z. Zhaotang, Proc. ICMMT'98, 1998, 795–798.
Звіти організацій з теми "H-270"
1
Parsons, Donald Kent. Correction to h-zr.27t: the H in Zirc Hydride S(α,β) Data at 1200K in the ENDF71SaB Library. Office of Scientific and Technical Information (OSTI), січень 2017. http://dx.doi.org/10.2172/1341852.
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2
Specht, W. L. F/H Area for ETF effluent (H-016 outfall), ceriodaphnia survival/reproduction test, test date: June 27, 1991. Office of Scientific and Technical Information (OSTI), December 1991. http://dx.doi.org/10.2172/10149472.
Повний текст джерела
3
Specht, W. L. F/H Area for ETF effluent (H-016 outfall), ceriodaphnia survival/reproduction test, test date: June 27, 1991. Office of Scientific and Technical Information (OSTI), January 1991. http://dx.doi.org/10.2172/5202403.
Повний текст джерела
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O'Connell, Kelly, David Burdick, Melissa Vaccarino, Colin Lock, Greg Zimmerman, and Yakuta Bhagat. Coral species inventory at War in the Pacific National Historical Park: Final report. National Park Service, 2024. http://dx.doi.org/10.36967/2302040.
Повний текст джерелаАнотація:
The War in the Pacific National Historical Park (WAPA), a protected area managed by the National Park Service (NPS), was established "to commemorate the bravery and sacrifice of those participating in the campaigns of the Pacific Theater of World War II and to conserve and interpret outstanding natural, scenic, and historic values on the island of Guam." Coral reef systems present in the park represent a vital element of Guam?s cultural, traditional, and economical heritage, and as such, are precious and in need of conservation. To facilitate the management of these resources, NPS determined that a scleractinian (stony coral) species survey was necessary to establish a baseline for existing coral communities and other important factors for conservation. EnviroScience, Inc. performed a survey of stony coral species, coral habitat, and current evidence of stressors at WAPA?s H?gat and Asan Units in 2022. This report summarizes these findings from a management perspective and compares its findings to previous survey data from 1977 and 1999 (Eldridge et al. 1977; Amesbury et al. 1999). WAPA is located on the tropical island of Guam, located on the west-central coast of the island, and encompasses 2,037 acres. Underwater resources are a significant component of the park, as 1,002 acres consists of water acres. The park is comprised of seven units, of which two of these, the H?gat and Asan Beach Units, include all the oceanic water acres for the park. The H?gat Beach Unit (local spelling, formerly known as ?Agat?) is located at the south-west portion of the park and consists of 38 land acres and 557 water acres (NPS 2003). The Asan Beach Unit consists of 109 acres of land and 445 water acres (NPS 2003). A current baseline for existing coral communities and other important factors for conservation necessitates the need for up-to-date data on the location, presence, relative abundance, and present health of corals. Park managers need this updated data to determine where and how to best focus conservation priorities and identify restoration opportunities. Management actions in park reef areas informed by this inventory included identifying locations where there were: high rates of sedimentation; high coral biomass; rare or threatened species, with a priority given to species endemic to Guam and listed as ?threatened? under the U.S. Endangered Species Act (ESA; Acropora globiceps, A. retusa, A. speciosa, and Seriatopora aculeata); coral persistence and decline, disease and/or nuisance species, including the crown-of-thorns starfish (Acanthaster cf. solaris, ?COTS?) and the sponge Terpios hoshinota; and bleached areas. All work carried out was in accordance with the NPS statement of work (SOW) requirements, which involved a quantitative inventory using both new and pre-existing transects. The resulting transects totaled 61 (including the four from the 1999 study), each measuring 50 meters in length and distributed across depths of up to 50 feet. Divers took photo-quadrat samples covering an area of approximately 9 m?, encompassing 50 photo-quadrats of dimensions 0.50 m x 0.36 m (n=50). The collective area surveyed across all 61 transects amounted to ~549 m?. Additionally, a qualitative search was conducted to enhance documentation of coral species that have limited distribution and might not be captured by transects, along with identifying harmful species and stressors. Timed roving diver coral diversity surveys were carried out at a total of 20 sites occurring within the waters of WAPA, including eight sites at the H?gat unit and 12 sites at the Asan unit. The findings from this report reveal significant disparities in benthic cover compositions between H?gat and Asan units. The H?gat unit exhibits high abundances of turf algae and unconsolidated sediment while the Asan beach unit presents a different scenario, with hard coral as the dominant benthic cover, followed closely by crustose coralline algae (CCA). The Asan unit is also more difficult to access from shore or boat relative to H?gat which provides that unit some protection from human influences. The Asan beach unit's prevalence of hard coral, CCA, and colonizable substrate suggests a more favorable environment for reef growth and the potential benefits of maintaining robust coral cover in the area. These distinct differences in benthic communities highlight the contrasting ecological dynamics and habitats of the two study areas. Across both H?gat and Asan beach unit transects, a total of 56 hard coral species were recorded from 27 genera, with 44 species recorded from the H?gat unit and 48 species recorded from the Asan unit. Of the four historical transects surveyed in the Asan unit from 1999, three experienced declines in percent coral cover (17.38-78.72%), while the fourth had an increase (10.98%). During the timed roving diver coral diversity surveys, a total of 245 hard coral species, including 241 scleractinian coral species representing 49 genera and 4 non-scleractinian coral species representing 4 genera were recorded. Uncertainties related to coral identification, unresolved boundaries between morphospecies, differences in taxonomists' perspectives, and the rapidly evolving state of coral taxonomy have significant implications for species determinations during coral diversity surveys. While the recent surveys have provided valuable insights into coral diversity in WAPA waters, ongoing taxonomic research and collaboration among experts will be essential to obtain a more comprehensive and accurate understanding of coral biodiversity in the region. Of the several ESA coral species that were searched for among the H?gat and Asan beach units, Acropora retusa was the only coral species found among quantitative transects (n=2) and A. globiceps was observed during coral diversity surveys. Acropora speciosa, which was dominant in the upper seaward slopes in 1977, is now conspicuously absent from all the surveys conducted in 2022 (Eldredge et al., 1977). The disappearance and reduction of these once-dominant species underscores the urgency of implementing conservation measures to safeguard the delicate balance of Guam's coral reefs and preserve the diversity and ecological integrity of these invaluable marine ecosystems. Other formerly common or locally abundant species were infrequently encountered during the diversity surveys, including Acropora monticulosa, A. sp. ?obtusicaulis?, A. palmerae, Stylophora sp. ?mordax?, Montipora sp. ?pagoensis?, and Millepora dichotoma. Significant bleaching-associated mortality was recorded for these species, most of which are restricted to reef front/margin zones exposed to moderate-to-high levels of wave energy. Sedimentation was present in both H?gat and the Asan units, though it was more commonly encountered in H?gat transects. While significant portions of the reef area within the WAPA H?gat unit are in poor condition due to a variety of stressors, some areas still hosted notable coral communities, which should be a potential focus for park management to prevent further degradation. There is a need for more effective management of point source pollution concerns, particularly when subpar wastewater treatment or runoff from areas with potential pollution or sediment-laden water is flowing from nearby terrestrial environments. Future monitoring efforts should aim to establish a framework that facilitates a deeper understanding of potential point source pollution incidents. This would empower park managers to collaborate with adjacent communities, both within and outside of park boundaries, to mitigate the localized impacts of pollution (McCutcheon and McKenna, 2021). COTS were encountered during transect surveys as well as in coral diversity surveys. including along the upper reef front/reef margin at site Agat-CS-2. The frequency of these observations, particularly in the WAPA H?gat unit and where stress-susceptible corals are already uncommonly encountered, raise concern about the ability of the populations of these coral species to recover following acute disturbance events, and calls in to question the ability of some of these species to persist in WAPA waters, and in Guam?s waters more broadly. More frequent crown-of-thorns control efforts, even if only a handful of sea stars are removed during a single effort, may be required to prevent further loss to vulnerable species. There were several documented incidents of Terpios hoshinota covering large sections of branching coral in the reef flat along transects, but it is still unclear how detrimental this sponge is to the overall reef system. There is a concern that elevated levels of organic matter and nutrients in the water, such as those resulting from sewage discharge or stormwater runoff, could lead to increased Terpios populations (De Voogd et al. 2013). Consequently, it is important to track populations in known areas of sedimentation and poor water quality. The presence of unique species at single survey sites within the study areas underscores the ecological importance of certain locations. Some species are known to occur in other locations in Guam, while a few may be limited to specific sites within WAPA waters. These differences are likely influenced by environmental and biological factors such as poor water quality, severe heat stress events, chronic predation by crown-of-thorns sea stars, disease, and reduced herbivore populations. These factors collectively shape the condition of the benthic community, leading to variations in species distribution and abundance across the study sites. Documenting coral stress and identifying potentially harmful species allows for proactive management strategies to prevent the establishment of nuisance or detrimental species while populations are still manageable. Updated data on the location, presence, relative abundance, and health of corals is essential for park managers to prioritize conservation efforts and identify restoration opportunities effectively. Observations from this report raise concerns about the health and resilience of coral ecosystems in the H?gat unit and emphasize the need for knowledge of local factors that shape benthic community structure. Understanding the drivers responsible for these variations is crucial for effective conservation and management strategies to preserve the ecological balance and overall health of coral reefs in both units. Continued monitoring efforts will be critical in assessing long-term trends and changes in benthic cover and enabling adaptive management approaches to safeguard these valuable marine ecosystems in the face of ongoing environmental challenges.
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Droby, Samir, Michael Wisniewski, Ron Porat, and Dumitru Macarisin. Role of Reactive Oxygen Species (ROS) in Tritrophic Interactions in Postharvest Biocontrol Systems. United States Department of Agriculture, December 2012. http://dx.doi.org/10.32747/2012.7594390.bard.
Повний текст джерелаАнотація:
To elucidate the role of ROS in the tri-trophic interactions in postharvest biocontrol systems a detailed molecular and biochemical investigation was undertaken. The application of the yeast biocontrol agent Metschnikowia fructicola, microarray analysis was performed on grapefruit surface wounds using an Affymetrix Citrus GeneChip. the data indicated that 1007 putative unigenes showed significant expression changes following wounding and yeast application relative to wounded controls. The expression of the genes encoding Respiratory burst oxidase (Rbo), mitogen-activated protein kinase (MAPK) and mitogen-activated protein kinase kinase (MAPKK), G-proteins, chitinase (CHI), phenylalanine ammonia-lyase (PAL), chalcone synthase (CHS) and 4-coumarate-CoA ligase (4CL). In contrast, three genes, peroxidase (POD), superoxide dismutase (SOD) and catalase (CAT), were down-regulated in grapefruit peel tissue treated with yeast cells. The yeast antagonists, Metschnikowia fructicola (strain 277) and Candida oleophila (strain 182) generate relatively high levels of super oxide anion (O2−) following its interaction with wounded fruit surface. Using laser scanning confocal microscopy we observed that the application of M. fructicola and C. oleophila into citrus and apple fruit wounds correlated with an increase in H2O2 accumulation in host tissue. The present data, together with our earlier discovery of the importance of H₂O₂ production in the defense response of citrus flavedo to postharvest pathogens, indicate that the yeast-induced oxidative response in fruit exocarp may be associated with the ability of specific yeast species to serve as biocontrol agents for the management of postharvest diseases. Effect of ROS on yeast cells was also studied. Pretreatment of the yeast, Candida oleophila, with 5 mM H₂O₂ for 30 min (sublethal) increased yeast tolerance to subsequent lethal levels of oxidative stress (50 mM H₂O₂), high temperature (40 °C), and low pH (pH 4). Suppression subtractive hybridization analysis was used to identify genes expressed in yeast in response to sublethal oxidative stress. Transcript levels were confirmed using semi quantitative reverse transcription-PCR. Seven antioxidant genes were up regulated. Pretreatment of the yeast antagonist Candida oleophila with glycine betaine (GB) increases oxidative stress tolerance in the microenvironment of apple wounds. ROS production is greater when yeast antagonists used as biocontrol agents are applied in the wounds. Compared to untreated control yeast cells, GB-treated cells recovered from the oxidative stress environment of apple wounds exhibited less accumulation of ROS and lower levels of oxidative damage to cellular proteins and lipids. Additionally, GB-treated yeast exhibited greater biocontrol activity against Penicillium expansum and Botrytis cinerea, and faster growth in wounds of apple fruits compared to untreated yeast. The expression of major antioxidant genes, including peroxisomal catalase, peroxiredoxin TSA1, and glutathione peroxidase was elevated in the yeast by GB treatment. A mild heat shock (HS) pretreatment (30 min at 40 1C) improved the tolerance of M. fructicola to subsequent high temperature (45 1C, 20–30 min) and oxidative stress (0.4 mol-¹) hydrogen peroxide, 20–60 min). HS-treated yeast cells showed less accumulation of reactive oxygen species (ROS) than non-treated cells in response to both stresses. Additionally, HS-treated yeast exhibited significantly greater (P≥0.0001) biocontrol activity against Penicillium expansum and a significantly faster (Po0.0001) growth rate in wounds of apple fruits stored at 25 1C compared with the performance of untreated yeast cells. Transcription of a trehalose-6-phosphate synthase gene (TPS1) was up regulated in response to HS and trehalose content also increased.
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Bäumler, Maximilian, and Matthias Lehmann. Generating representative test scenarios: The FUSE for Representativity (fuse4rep) process model for collecting and analysing traffic observation data. TU Dresden, 2024. http://dx.doi.org/10.26128/2024.2.
Повний текст джерелаАнотація:
Scenario-based testing is a pillar of assessing the effectiveness of automated driving systems (ADSs). For data-driven scenario-based testing, representative traffic scenarios need to describe real road traffic situations in compressed form and, as such, cover normal driving along with critical and accident situations originating from different data sources. Nevertheless, in the choice of data sources, a conflict often arises between sample quality and depth of information. Police accident data (PD) covering accident situations, for example, represent a full survey and thus have high sample quality but low depth of information. However, for local video-based traffic observation (VO) data using drones and covering normal driving and critical situations, the opposite is true. Only the fusion of both sources of data using statistical matching can yield a representative, meaningful database able to generate representative test scenarios. For successful fusion, which requires as many relevant, shared features in both data sources as possible, the following question arises: How can VO data be collected by drones and analysed to create the maximum number of relevant, shared features with PD? To answer that question, we used the Find–Unify–Synthesise–Evaluation (FUSE) for Representativity (FUSE4Rep) process model.We applied the first (“Find”) and second (“Unify”) step of this model to VO data and conducted drone-based VOs at two intersections in Dresden, Germany, to verify our results. We observed a three-way and a four-way intersection, both without traffic signals, for more than 27 h, following a fixed sample plan. To generate as many relevant information as possible, the drone pilots collected 122 variables for each observation (which we published in the ListDB Codebook) and the behavioural errors of road users, among other information. Next, we analysed the videos for traffic conflicts, which we classified according to the German accident type catalogue and matched with complementary information collected by the drone pilots. Last, we assessed the crash risk for the detected traffic conflicts using generalised extreme value (GEV) modelling. For example, accident type 211 was predicted as happening 1.3 times per year at the observed four-way intersection. The process ultimately facilitated the preparation of VO data for fusion with PD. The orientation towards traffic conflicts, the matched behavioural errors and the estimated GEV allowed creating accident-relevant scenarios. Thus, the model applied to VO data marks an important step towards realising a representative test scenario database and, in turn, safe ADSs.
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Goetsch, Arthur L., Yoav Aharoni, Arieh Brosh, Ryszard (Richard) Puchala, Terry A. Gipson, Zalman Henkin, Eugene D. Ungar, and Amit Dolev. Energy Expenditure for Activity in Free Ranging Ruminants: A Nutritional Frontier. United States Department of Agriculture, June 2009. http://dx.doi.org/10.32747/2009.7696529.bard.
Повний текст джерелаАнотація:
Heat production (HP) or energy expenditure for activity (EEa) is of fundamental nutritional importance for livestock because it determines the proportion of ingested nutrients available for productive functions. Previous estimates of EEa are unreliable and vary widely with different indirect methodologies. This leads to erroneous nutritional strategies, especially when intake on pasture does not meet nutritional requirements and supplementation is necessary for acceptable production. Therefore, the objective of this project was to measure EEa in different classes of livestock (beef cattle and goats) over a wide range of ecological and management conditions to develop and evaluate simple means of prediction. In the first study in Israel, small frame (SF) and large frame (LF) cows (268 and 581 kg) were monitored during spring, summer, and autumn. Feed intake by SF cows per unit of metabolic weight was greater (P < 0.001) than that by LF cows in both spring and summer and their apparent selection of higher quality herbage in spring was greater (P < 0.10) than that of LF cows. SF cows grazed more hours per day and walked longer distances than the LF cows during all seasons. The coefficient of specific costs of activities (kJ•kg BW-0.75•d-1) and of locomotion (J•kg BW-0.75•m-1) were smaller for the SF cows. In the second study, cows were monitored in March, May, and September when they grazed relatively large plots, 135 and 78 ha. Energy cost coefficients of standing, grazing, and horizontal locomotion derived were similar to those of the previous study based on data from smaller plots. However, the energy costs of walking idle and of vertical locomotion were greater than those found by Brosh et al. (2006) but similar to those found by Aharoni et al. (2009). In the third study, cows were monitored in February and May in a 78-ha plot with an average slope of 15.5°, whereas average plot slopes of the former studies ranged between 4.3 and 6.9°. Energy cost coefficients of standing, grazing, and walking idle were greater than those calculated in the previous studies. However, the estimated energy costs of locomotion were lower in the steeper plot. A comparison on a similar HP basis, i.e., similar metabolizable energy (ME) intake, shows that the daily energy spent on activities in relation to daily HP increased by 27% as the average plot slope increased from 5.8 and 6.02 to 15.5°. In the fourth study, cows grazing in a woodland habitat were monitored as in previous studies in December, March, and July. Data analysis is in progress. In the first US experiment, Boer and Spanish does with two kids were used in an experiment beginning in late spring at an average of 24 days after kidding. Two does of each breed resided in eight 0.5-ha grass/forb pastures. Periods of 56, 60, 63, 64, and 73 days in length corresponded to mid-lactation, early post-weaning, the late dry period, early gestation, and mid-gestation. EEa expressed as a percentage of the ME requirement for maintenance plus activity in confinement (EEa%) was not influenced by stocking rate, breed, or period, averaging 49%. Behavioral activities (e.g., time spent grazing, walking, and idle, distance traveled) were not highly related to EEa%, although no-intercept regressions against time spent grazing/eating and grazing/eating plus walking indicated an increase in EEa% of 5.8 and 5.1%/h, respectively. In the second study, animal types were yearling Angora doeling goats, yearling Boer wether goats, yearling Spanish wether goats, and Rambouilletwether sheep slightly more than 2 yr of age. Two animals of each type were randomly allocated to one of four pastures 9.3, 12.3, 4.6, and 1.2 ha in area. The experiment was conducted in the summer with three periods, 30, 26, and 26 days in length. EEa% was affected by an interaction between animal type and period (Angora: 16, 17, and 15; Boer: 60, 67, and 34; Spanish: 46, 62, and 42; sheep: 22, 12, and 22% in periods 1, 2, and 3, respectively (SE = 6.1)). EEa% of goats was predicted with moderate accuracy (R2 = 0.40-0.41) and without bias from estimates of 5.8 and 5.1%/h spent grazing/eating and grazing/eating plus walking, respectively, determined in the first experiment; however, these methods were not suitable for sheep. These methods of prediction are simpler and more accurate than currently recommended for goats by the National Research Council.