414 research outputs found
Impact of the dicyanomethylene substitution position on the cyclophane macrocycle formation in carbazole-based biradicals
π-Conjugated biradical compounds, featuring unique unsaturated valences and radical centers in the ground state, are fundamentally important for understanding the nature of chemical bonds and have potential applications in material science. [1] Recently, it has been demonstrated that several -conjugated mono- and biradicals systems form long strain -bonds between two unpaired electrons resulting in macrocyclic or staircase oligomers or polymers by self-assembly processes. [2] Therefore, these materials are potential building blocks for dynamic covalent chemistry (DCC) since the aggregates can be formed or broken upon soft external stimuli. For instance, 2,7-dicyanomethylene-9-(2-ethylhexyl)carbazole biradical (p-Cz-alkyl in Figure 1) reversibly converts upon soft stimuli (temperature, pressure, light) to a cyclophane tetramer as a result from the formation (or bond cleavage) of long C-C single bonds.[3] Here, we present an experimental and theoretical study in order to investigate how the N-substitution and the change from para- to meta-dicyanomethylene substitution on carbazole-based biradicals affects their biradical character and thus, their tendency to act as useful motifs for DCC (see Figure 1).Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec
Analyzing Interactions of Calmodulin with HIV-1 Matrix Protein
Human immunodeficiency virus (HIV) attacks the immune system and if left untreated, could cause acquired immunodeficiency syndrome (AIDS). The HIV matrix protein (HIV-MA) is involved in replication and regulation of the HIV virus. Calmodulin (CaM), a calcium-binding protein found in all eukaryotes, has a potential role in the viral replication of HIV-MA which plays a key role in the replication of HIV. In order to investigate the interactions between calmodulin and the HIV-MA, a series of titrations with CaM are performed using circular dichroism. Circular dichroism (CD) uses circularly polarized light to observe the secondary structure of a molecule. The circularly polarized light is broken up into left and right components. When the molecule contains a chiral center, the left and right components are absorbed to different extents, and the differential absorption is measured with CD. Through a series of titrations, the chemical environment is changed in small increments so the molecule will experience conformational changes. As the conformation changes, CD is used to measure the ellipticity which provides a better understanding of the secondary structure that is a result of these chemical interactions. Since CaM plays a potential role in the viral replication of HIV-MA, CD is used to investigate the protein-protein interactions and conformational changes
An infrared integrated optic astronomical beam combiner for stellar interferometry at 3-4 microns
Integrated-optic, astronomical, two-beam and three-beam, interferometric
combiners have been designed and fabricated for operation in the L band (3 - 4
microns) for the first time. The devices have been realized in
titanium-indiffused, x-cut lithium niobate substrates, and on-chip
electro-optic fringe scanning has been demonstrated. White light fringes were
produced in the laboratory using the two-beam combiner integrated with an
on-chip Y-splitter.Comment: This paper was published in Optics Express and is made available as
an electronic reprint with the permission of OSA. The paper can be found at
the following URL on the OSA website: http://www.opticsinfobase.org/oe.
Systematic or multiple reproduction or distribution to multiple locations via
electronic or other means is prohibited and is subject to penalties under la
Singular del Pezzo surfaces that are equivariant compactifications
We determine which singular del Pezzo surfaces are equivariant
compactifications of G_a^2, to assist with proofs of Manin's conjecture for
such surfaces. Additionally, we give an example of a singular quartic del Pezzo
surface that is an equivariant compactification of a semidirect product of G_a
and G_m.Comment: 14 pages, main result extended to non-closed ground field
Comprehensive biomarker analyses identifies HER2, EGFR, MET RNA expression and thymidylate synthase 5'UTR SNP as predictors of benefit from S-1 adjuvant chemotherapy in Japanese patients with stage II/III gastric cancer
Purpose: A comprehensive molecular analysis was conducted to identify prognostic and predictive markers for adjuvant S-1 chemotherapy in stage II/III Japanese gastric cancer (GC) patients and to evaluate their potential suitability for alternative cytotoxic or targeted drugs.
Experimental Design: We investigated genetic polymorphisms of enzymes potentially involved in 5-fluoruracil (5-FU) metabolism as well as platinum resistance, previously identified genomic subtypes potentially predicting 5-FU benefit, and mRNA expression levels of receptor tyrosine kinases and KRAS as potential treatment targets in a single institution cohort of 252 stage II/III GC patients treated with or without S-1 after D2 gastrectomy.
Results: 88% and 62% GC had a potentially 5-FU sensitive phenotype by SNP analyses of TS 3'UTR, and TS 5'UTR, respectively. 24%, 46%, 40%, 5%, and 44% GC had a potentially platinum sensitive phenotype by SNP analyses of GSTP1, ERCC1 rs11615, ERCC1 rs3212986, ERCC2, and XRCC1, respectively. High HER2, EGFR, FGFR2, or MET mRNA expression was observed in 49%, 66%, 72%, and 54% GC, respectively. High HER2 expression was the only significant prognosticator (HR=3.912, 95%CI: 1.706-8.973, p=0.0005). High HER2 (p=0.031), low EGFR (p=0.124), high MET (p=0.165) RNA expression, and TS 5'UTR subtype 2R/2R, 2R/3C, or 3C (p=0.058) were significant independent predictors for S-1 resistance.
Conclusions: The present study suggests that platinum-based or RTK targeted agents could be alternative treatment options for a substantial subgroup of Japanese GC patients currently treated with S-1. HER2, EGFR, MET, and TS 5'UTR SNP appear to be promising predictive markers for S-1 resistance warranting validation in an independent GC series
Micro-Raman study of crichtonite group minerals enclosed into mantle garnet
We report the first comprehensive micro-Raman study of crichtonite group minerals (CGM) as inclusions in pyropic garnet grains from peridotite and pyroxenite mantle xenoliths of the Yakutian kimberlites as well as in garnet xenocrysts from the Aldan shield lamprophyres (Russia). The CGM form (i) morphologically oriented needles, lamellae, and short prisms and (ii) optically unoriented subhedral to euhedral grains, either single or intergrown with other minerals. We considered common mantle-derived CGM species (like loveringite, lindsleyite, and their analogues), with Ca, Ba, or Sr dominating in the dodecahedral A site and Zr or Fe in the octahedral B site. The Raman bands at the region of 600–830 cm−1 are indicative of CGM and their crystal-chemical distinction, although the intensity and shape of the bands appear to be dependent on laser beam power and wavelength. The factor-group analysis based on the loveringite crystal structure showed the octahedral and tetrahedral cation groups with 18f and 6c Wyckoff positions, namely, dominantly TiO6 and to a lower extent CrO6, MgO4, and FeO4 groups, to be the major contributors to the Raman spectral features. The ionic groups with dodecahedral (M0) and octahedral (M1) coordination are inactive for Raman scattering while active in infrared absorption. A number of observed Raman modes in the CGM spectra are several times lower than that predicted by the factor group analysis. The noticed broadening of modes in the CGM Raman spectra may result from a combining of bands at the narrow frequency shift regions. Solid solution behavior, luminescence, and partial metamictization of the CGM may exert additional influence on the Raman band shape. The Raman spectral features showed CGM to be accurately identified and distinguished from other Ti-, Fe-, Cr-, and Zr-containing oxides (e.g., ilmenite or those of spinel and magnetoplumbite groups) occurring as accessory mantle minerals. © 2020 The Authors. Journal of Raman Spectroscopy published by John Wiley & Sons LtdRussian Science Foundation, RSF: 18‐77‐10062Council on grants of the President of the Russian FederationThis study was supported by the Russian Science Foundation (Grant 18‐77‐10062). The equipment of the Ural Center for Shared Use «Modern Nanotechnology», Ural Federal University, and the Analytical Center for Multi‐elemental and Isotope Research, IGM, was used. Sampling was supported by the Russian Federation state assignment project of IGM. We are grateful to Nikolai V. Sobolev for Samples O‐173, O‐39, and O‐264. Vladimir N. Korolyuk, Elena N. Nigmatulina (IGM), and Allan Patchen (UT) are highly appreciated for the help with EMP analyses. We express our sincere thanks to F. Nestola and an anonymous reviewer for their thorough reviews and helpful suggestions, and to C. Marshall for regardful editorial handling of the manuscript on every stage of its revision
Continental flood basalts derived from the hydrous mantle transition zone
It has previously been postulated that the Earth's hydrous mantle transition zone may play a key role in intraplate magmatism, but no confirmatory evidence has been reported. Here we demonstrate that hydrothermally altered subducted oceanic crust was involved in generating the late Cenozoic Chifeng continental flood basalts of East Asia. This study combines oxygen isotopes with conventional geochemistry to provide evidence for an origin in the hydrous mantle transition zone. These observations lead us to propose an alternative thermochemical model, whereby slab-triggered wet upwelling produces large volumes of melt that may rise from the hydrous mantle transition zone. This model explains the lack of pre-magmatic lithospheric extension or a hotspot track and also the arc-like signatures observed in some large-scale intracontinental magmas. Deep-Earth water cycling, linked to cold subduction, slab stagnation, wet mantle upwelling and assembly/breakup of supercontinents, can potentially account for the chemical diversity of many continental flood basalts
Environmental effects of a marine fish farm of gilthead seabream (Sparus aurata) in the NW Mediterranean Sea on water column and sediment
This study examined the effects of organic enrichment on water column, sediments and macrofauna caused by a fish farm in the Mediterranean Sea. Samples were collected on four sampling campaigns over a one-year cycle. Significant differences were found in the water column in dissolved oxygen, dissolved inorganic nitrogen, phosphate and total phosphorus concentrations between the fish farm and the control. The increase in the dissolved inorganic nitrogen and phosphate concentrations at the fish farm modified the stoichiometric ratios between nutrients, with silicate acting as limiting nutrient at the fish farm 11% more than at the control. Nevertheless, chlorophyll a concentration in the water column was higher at the control station, probably due to the fouling of the underwater fish farm structures. Significant differences were found in sediment concentrations of organic matter, total phosphorus and redox potential between the fish farm and the control. The Canonical Correlation Analysis indicated that organic matter, total phosphorus, redox potential and% of gravels accounted for 68.9% of the total variance in the species data. Changes were observed in macrofauna, with a decrease in number of species and up to a nine-fold increase in abundance with respect to the control. © 2013 Blackwell Publishing Ltd.We would like to thank the Caja del Mediterraneo (CAM) for a pre-doctoral fellowship fund for this research and Antonio Asuncion Acuigroup Maremar Manager, for the facilities and support in conducting the study. The translation of this paper was funded by the Universidad Politecnica de Valencia, Spain.Morata Higón, T.; Falco Giaccaglia, SL.; Gadea, I.; Sospedra Ciscar, J.; Rodilla Alamá, M. (2013). Environmental effects of a marine fish farm of gilthead seabream (Sparus aurata) in the NW Mediterranean Sea on water column and sediment. Aquaculture Research. 1-16. https://doi.org/10.1111/are.12159S116Aguado F. 2001 Impacto ambiental de los sistemas piscícolas marinos: la acuicultura en jaulas flotantes. Series de química oceanográfica 35 83Aguado-Giménez, F., & García-García, B. (2004). Assessment of some chemical parameters in marine sediments exposed to offshore cage fish farming influence: a pilot study. Aquaculture, 242(1-4), 283-295. doi:10.1016/j.aquaculture.2004.08.035Aksu M. Kocatas A. 2007 Environmental effects of the three fish farms in Izmir Bay (Aegean Sea-Turkey) on water column and sediment 414Asociación Empresarial de Productores de Cultivos Marinos (APROMAR) 2011 La Acuicultura Marina de Peces en España 77Banta, G., Holmer, M., Jensen, M., & Kristensen, E. (1999). Effects of two polychaete worms, Nereis diversicolor and Arenicola marina, on aerobic and anaerobic decomposition in a sandy marine sediment. Aquatic Microbial Ecology, 19, 189-204. doi:10.3354/ame019189Borja, Á., Rodríguez, J. G., Black, K., Bodoy, A., Emblow, C., Fernandes, T. F., … Angel, D. (2009). Assessing the suitability of a range of benthic indices in the evaluation of environmental impact of fin and shellfish aquaculture located in sites across Europe. Aquaculture, 293(3-4), 231-240. doi:10.1016/j.aquaculture.2009.04.037Braeckman, U., Provoost, P., Gribsholt, B., Van Gansbeke, D., Middelburg, J., Soetaert, K., … Vanaverbeke, J. (2010). Role of macrofauna functional traits and density in biogeochemical fluxes and bioturbation. Marine Ecology Progress Series, 399, 173-186. doi:10.3354/meps08336Chou, C. L., Haya, K., Paon, L. A., Burridge, L., & Moffatt, J. D. (2002). Aquaculture-related trace metals in sediments and lobsters and relevance to environmental monitoring program ratings for near-field effects. Marine Pollution Bulletin, 44(11), 1259-1268. doi:10.1016/s0025-326x(02)00219-9Christensen, P., Rysgaard, S., Sloth, N., Dalsgaard, T., & Schwærter, S. (2000). Sediment mineralization, nutrient fluxes, denitrification and dissimilatory nitrate reduction to ammonium in an estuarine fjord with sea cage trout farms. Aquatic Microbial Ecology, 21, 73-84. doi:10.3354/ame021073Chung, I.-K., Kang, Y.-H., Yarish, C., George, P. K., & Lee, J.-A. (2002). Application of Seaweed Cultivation to the Bioremediation of Nutrient-Rich Effluent. ALGAE, 17(3), 187-194. doi:10.4490/algae.2002.17.3.187Cromey, C. J., Nickell, T. D., & Black, K. D. (2002). DEPOMOD—modelling the deposition and biological effects of waste solids from marine cage farms. Aquaculture, 214(1-4), 211-239. doi:10.1016/s0044-8486(02)00368-xCugier, P., Struski, C., Blanchard, M., Mazurié, J., Pouvreau, S., Olivier, F., … Thiébaut, E. (2010). Assessing the role of benthic filter feeders on phytoplankton production in a shellfish farming site: Mont Saint Michel Bay, France. Journal of Marine Systems, 82(1-2), 21-34. doi:10.1016/j.jmarsys.2010.02.013Davies, I. M., McHenery, J. G., & Rae, G. H. (1997). Environmental risk from dissolved ivermectin to marine organisms. Aquaculture, 158(3-4), 263-275. doi:10.1016/s0044-8486(97)00209-3Dean, R. J., Shimmield, T. M., & Black, K. D. (2007). Copper, zinc and cadmium in marine cage fish farm sediments: An extensive survey. Environmental Pollution, 145(1), 84-95. doi:10.1016/j.envpol.2006.03.050Delgado, O., Ruiz, J., Pérez, M., Romero, J., & Ballesteros, E. (1999). Effects of fish farming on seagrass (Posidonia oceanica) in a Mediterranean bay: seagrass decline after organic loading cessation. Oceanologica Acta, 22(1), 109-117. doi:10.1016/s0399-1784(99)80037-1Dell’Anno, A., Mei, M. ., Pusceddu, A., & Danovaro, R. (2002). Assessing the trophic state and eutrophication of coastal marine systems: a new approach based on the biochemical composition of sediment organic matter. Marine Pollution Bulletin, 44(7), 611-622. doi:10.1016/s0025-326x(01)00302-2Ferrón, S., Ortega, T., & Forja, J. M. (2009). Benthic fluxes in a tidal salt marsh creek affected by fish farm activities: Río San Pedro (Bay of Cádiz, SW Spain). Marine Chemistry, 113(1-2), 50-62. doi:10.1016/j.marchem.2008.12.002Garren, M., Smriga, S., & Azam, F. (2008). Gradients of coastal fish farm effluents and their effect on coral reef microbes. Environmental Microbiology, 10(9), 2299-2312. doi:10.1111/j.1462-2920.2008.01654.xHolmer, M., & Kristensen, E. (1992). Impact of marine fish cage farming on metabolism and sulfate reduction of underlying sediments. Marine Ecology Progress Series, 80, 191-201. doi:10.3354/meps080191Holmer, M., Wildish, D., & Hargrave, B. (s. f.). Organic Enrichment from Marine Finfish Aquaculture and Effects on Sediment Biogeochemical Processes. Environmental Effects of Marine Finfish Aquaculture, 181-206. doi:10.1007/b136010Huang, Y., Hsieh, H., Huang, S., Meng, P., Chen, Y., Keshavmurthy, S., … Chen, C. (2011). Nutrient enrichment caused by marine cage culture and its influence on subtropical coral communities in turbid waters. Marine Ecology Progress Series, 423, 83-93. doi:10.3354/meps08944Johansson, O., & Wedborg, M. (1980). The ammonia-ammonium equilibrium in seawater at temperatures between 5 and 25�C. Journal of Solution Chemistry, 9(1), 37-44. doi:10.1007/bf00650135Johansson, D., Juell, J.-E., Oppedal, F., Stiansen, J.-E., & Ruohonen, K. (2007). The influence of the pycnocline and cage resistance on current flow, oxygen flux and swimming behaviour of Atlantic salmon (Salmo salar L.) in production cages. Aquaculture, 265(1-4), 271-287. doi:10.1016/j.aquaculture.2006.12.047Juell, J.-E., & Fosseidengen, J. E. (2004). Use of artificial light to control swimming depth and fish density of Atlantic salmon (Salmo salar) in production cages. Aquaculture, 233(1-4), 269-282. doi:10.1016/j.aquaculture.2003.10.026Justić, D., Rabalais, N. N., Turner, R. E., & Dortch, Q. (1995). Changes in nutrient structure of river-dominated coastal waters: stoichiometric nutrient balance and its consequences. Estuarine, Coastal and Shelf Science, 40(3), 339-356. doi:10.1016/s0272-7714(05)80014-9Karakassis, I., Tsapakis, M., & Hatziyanni, E. (1998). Seasonal variability in sediment profiles beneath fish farm cages in the Mediterranean. Marine Ecology Progress Series, 162, 243-252. doi:10.3354/meps162243Karakassis, I. (2000). Impact of cage farming of fish on the seabed in three Mediterranean coastal areas. ICES Journal of Marine Science, 57(5), 1462-1471. doi:10.1006/jmsc.2000.0925Basaran, A. K., Aksu, M., & Egemen, O. (2009). Impacts of the fish farms on the water column nutrient concentrations and accumulation of heavy metals in the sediments in the eastern Aegean Sea (Turkey). Environmental Monitoring and Assessment, 162(1-4), 439-451. doi:10.1007/s10661-009-0808-xLa Rosa, T., Mirto, S., Favaloro, E., Savona, B., Sarà, G., Danovaro, R., & Mazzola, A. (2002). Impact on the water column biogeochemistry of a Mediterranean mussel and fish farm. Water Research, 36(3), 713-721. doi:10.1016/s0043-1354(01)00274-3Maldonado, M., Carmona, M. C., Echeverría, Y., & Riesgo, A. (2005). The environmental impact of Mediterranean cage fish farms at semi-exposed locations: does it need a re-assessment? Helgoland Marine Research, 59(2), 121-135. doi:10.1007/s10152-004-0211-5Mantzavrakos, E., Kornaros, M., Lyberatos, G., & Kaspiris, P. (2007). Impacts of a marine fish farm in Argolikos Gulf (Greece) on the water column and the sediment. Desalination, 210(1-3), 110-124. doi:10.1016/j.desal.2006.05.037Martins, C. I. M., Galhardo, L., Noble, C., Damsgård, B., Spedicato, M. T., Zupa, W., … Kristiansen, T. (2011). Behavioural indicators of welfare in farmed fish. Fish Physiology and Biochemistry, 38(1), 17-41. doi:10.1007/s10695-011-9518-8Morata, T., Sospedra, J., Falco, S., & Rodilla, M. (2012). Exchange of nutrients and oxygen across the sediment–water interface below a Sparus aurata marine fish farm in the north-western Mediterranean Sea. Journal of Soils and Sediments, 12(10), 1623-1632. doi:10.1007/s11368-012-0581-2Murray L. Bulling M. Mayor D. Sanz-Lázaro C. Paton G. Killham K. Sosal M. 2008 Interactive effects of biodiversity, copper and a chemotherapeutant on marine benthic function Proceedings of the World Conference on Marine Biodiversity (MARBEF) Valencia, SpainNizzoli, D., Bartoli, M., & Viaroli, P. (2007). Oxygen and ammonium dynamics during a farming cycle of the bivalve Tapes philippinarum. Hydrobiologia, 587(1), 25-36. doi:10.1007/s10750-007-0683-9Olivos-Ortiz, A. (2002). Continental runoff of nutrients and their possible influence over stoichiometrical relations (DIN:P:Si) in the Northwest Mediterranean waters. Ciencias Marinas, 28(4), 393-406. doi:10.7773/cm.v28i4.235Olsen L.M. Holmer M. Olsen Y. 2008 Perspectives of nutrient emission from fish aquaculture in coastal waters. Literature review with evaluated state of knowledge 87Oppedal, F., Juell, J.-E., & Johansson, D. (2007). Thermo- and photoregulatory swimming behaviour of caged Atlantic salmon: Implications for photoperiod management and fish welfare. Aquaculture, 265(1-4), 70-81. doi:10.1016/j.aquaculture.2007.01.050Pinedo, S., García, M., Satta, M. P., Torres, M. de, & Ballesteros, E. (2007). Rocky-shore communities as indicators of water quality: A case study in the Northwestern Mediterranean. Marine Pollution Bulletin, 55(1-6), 126-135. doi:10.1016/j.marpolbul.2006.08.044Porrello, S., Tomassetti, P., Manzueto, L., Finoia, M. G., Persia, E., Mercatali, I., & Stipa, P. (2005). The influence of marine cages on the sediment chemistry in the Western Mediterranean Sea. Aquaculture, 249(1-4), 145-158. doi:10.1016/j.aquaculture.2005.02.042Rosenberg, R. (2001). Marine benthic faunal successional stages and related sedimentary activity. Scientia Marina, 65(S2), 107-119. doi:10.3989/scimar.2001.65s2107Sakamaki, T., Nishimura, O., & Sudo, R. (2006). Tidal time-scale variation in nutrient flux across the sediment–water interface of an estuarine tidal flat. Estuarine, Coastal and Shelf Science, 67(4), 653-663. doi:10.1016/j.ecss.2006.01.005Sanz-Lázaro, C., & Marín, A. (2011). Diversity Patterns of Benthic Macrofauna Caused by Marine Fish Farming. Diversity, 3(2), 176-199. doi:10.3390/d3020176Siokou-Frangou, I., Christaki, U., Mazzocchi, M. G., Montresor, M., Ribera d'Alcalá, M., Vaqué, D., & Zingone, A. (2010). Plankton in the open Mediterranean Sea: a review. Biogeosciences, 7(5), 1543-1586. doi:10.5194/bg-7-1543-2010Teasdale, P. R., Minett, A. I., Dixon, K., Lewis, T. W., & Batley, G. E. (1998). Practical improvements for redox potential (EH) measurements and the application of a multiple-electrode redox probe (MERP) for characterising sediment in situ. Analytica Chimica Acta, 367(1-3), 201-213. doi:10.1016/s0003-2670(98)00171-8Vila, M., Garcés, E., Masó, M., & Camp, J. (2001). Is the distribution of the toxic dinoflagellate Alexandrium catenella expanding along the NW Mediterranean coast? Marine Ecology Progress Series, 222, 73-83. doi:10.3354/meps222073Vita, R., & Marin, A. (2007). Environmental impact of capture-based bluefin tuna aquaculture on benthic communities in the western Mediterranean. Aquaculture Research, 38(4), 331-339. doi:10.1111/j.1365-2109.2007.01649.xWajsbrot, N., Gasith, A., Krom, M. D., & Popper, D. M. (1991). Acute toxicity of ammonia to juvenile gilthead seabream Sparus aurata under reduced oxygen levels. Aquaculture, 92, 277-288. doi:10.1016/0044-8486(91)90029-7Wu, R. S. . (2002). Hypoxia: from molecular responses to ecosystem responses. Marine Pollution Bulletin, 45(1-12), 35-45. doi:10.1016/s0025-326x(02)00061-9Yucel-Gier, G., Kucuksezgin, F., & Kocak, F. (2007). Effects of fish farming on nutrients and benthic community structure in the Eastern Aegean (Turkey). Aquaculture Research, 38(3), 256-267. doi:10.1111/j.1365-2109.2007.01661.
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