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51.
《Free radical research》2013,47(1-2):75-84
The use of nitrose compounds and nitrones as spin traps for the detection of short-lived inorganic radicals is discussed. To a certain degree nitrones and nitroso compounds are complementary. While nitroso compounds are superior with respect to spin trapping metal-centred radicals, nitrones form more persistent spin adducts with most small inorganic radicals.Erroneous results may be obtained when hydrolysis and redox reactions involving the spin adducts are ignored. Spin trapping of pseudohalide radicals (·Nj· ·CN, ·SCN) are discussed in more detail. 相似文献
52.
Mark Olischläger Inka Bartsch Lars Gutow Christian Wiencke 《Phycological Research》2013,61(3):180-190
Rising atmospheric CO2‐concentrations will have severe consequences for a variety of biological processes. We investigated the responses of the green alga Ulva lactuca (Linnaeus) to rising CO2‐concentrations in a rockpool scenario. U. lactuca was cultured under aeration with air containing either preindustrial pCO2 (280 μatm) or the pCO2 predicted by the end of the 21st century (700 μatm) for 31 days. We addressed the following question: Will elevated CO2‐concentrations affect photosynthesis (net photosynthesis, maximum relative electron transport rate (rETR(max)), maximum quantum yield (Fv/Fm), pigment composition) and growth of U. lactuca in rockpools with limited water exchange? Two phases of the experiment were distinguished: In the initial phase (day 1–4) the Seawater Carbonate System (SWCS) of the culture medium could be adjusted to the selected atmospheric pCO2 condition by continuous aeration with target pCO2 values. In the second phase (day 4–31) the SWCS was largely determined by the metabolism of the growing U. lactuca biomass. In the initial phase, Fv/Fm and rETR(max) were only slightly elevated at high CO2‐concentrations, whereas growth was significantly enhanced. After 31 days the Chl a content of the thalli was significantly lower under future conditions and the photosynthesis of thalli grown under preindustrial conditions was not dependent on external carbonic anhydrase. Biomass increased significantly at high CO2‐concentrations. At low CO2‐concentrations most adult thalli disintegrated between day 14 and 21, whereas at high CO2‐concentrations most thalli remained integer until day 31. Thallus disintegration at low CO2‐concentrations was mirrored by a drastic decline in seawater dissolved inorganic carbon and HCO3?. Accordingly, the SWCS differed significantly between the treatments. Our results indicated a slight enhancement of photosynthetic performance and significantly elevated growth of U. lactuca at future CO2‐concentrations. The accelerated thallus disintegration at high CO2‐concentrations under conditions of limited water exchange indicates additional CO2 effects on the life cycle of U. lactuca when living in rockpools. 相似文献
53.
Muwaffaq R. Karajeh Farah M. Al-Nasir 《Archives Of Phytopathology And Plant Protection》2013,46(16):1912-1920
Influence of different nitrogen salts at electrical conductivity levels (EC2, 4 and 8?mmhos/cm) on tomato and root-knot nematode (Meloidogyne javanica) and their interactions was evaluated under field conditions. It was found that both diammonium phosphate ((NH4)2HPO4) and ammonium sulphate ((NH4)2SO4) were more effective than ammonium chloride (NH4Cl) in causing an obvious suppression of M. javanica infection on tomato through reducing root galling and nematode reproduction and improving tomato growth and yield and their suppressive effect was similar to that of oxamyl or ethoprophos. At higher ECs, the tested nitrogen salts did not greatly affect pH, EC and salinity of rhizospheric soil except NH4Cl at EC8 that caused higher EC and salinity over the untreated control which makes NH4Cl less suitable candidate. Therefore, the use of (NH4)2HPO4 and (NH4)2SO4 alone or in combination with other control measures could control M. javanica and improve the growth and yield of tomato under field conditions. 相似文献
54.
We investigated the interaction of rhizospheric nitric oxide (NO) concentration (i.e. low, ambient or high) and soil nitrogen (N) availability (i.e. low or high) with organic and inorganic N uptake by fine roots of Pinus sylvestris L. seedlings by 15N feeding experiments under controlled conditions. N metabolites in fine roots were analysed to link N uptake to N nutrition. NO affected N uptake depending on N source and soil N availability. The suppression of nitrate uptake in the presence of ammonium and glutamine was overruled by high NO. The effects of NO on N uptake with increasing N availability showed different patterns: (1) increasing N uptake regardless of NO concentration (i.e. ammonium); (2) increasing N uptake only with high NO concentration (i.e. nitrate and arginine); and (3) decreasing N uptake (i.e. glutamine). At low N availability and high NO nitrate accumulated in the roots indicating insufficient substrates for nitrate reduction or its storage in root vacuoles. Individual amino acid concentrations were negatively affected with increasing NO (i.e. asparagine and glutamine with low N availability, serine and proline with high N availability). In conclusion, this study provides first evidence that NO affects N uptake and metabolism in a conifer. 相似文献
55.
56.
《Bioscience, biotechnology, and biochemistry》2013,77(2):456-458
A chemotaxis-defective mutant of Enterobacter cloacae IFO3320, designated EC1, was isolated after N-methyl-N'-nitro-N-nitrosoguanidine (NTG) mutagenesis. Computer-assisted capillary assays showed that EC1 failed to show chemotactic responses to peptone and inorganic phosphate (Pi). Cloning and sequence analysis showed that EC1 is a cheR mutant, suggesting that Pi taxis by E. cloacae is dependent on a methyl-accepting chemotaxis protein(s)(MCP). EC1 was further mutagenized with NTG to construct cheR pstS and cheR pstA double mutants. A recombinant plasmid pECT01.2, which contained the E. cloacae cheR gene, restored the ability of these double mutants to show chemotaxis toward peptone but not Pi. These results suggest that the phosphate-specific transport (Pst) system, together with a MCP(s), is required for detecting Pi in E. cloacae. 相似文献
57.
Chemotaxis allows microorganisms to rapidly respond to different environmental stimuli; however, understanding of this process is limited by conventional assays, which typically focus on the response of single axenic cultures to given compounds. In this study, we used a modified capillary assay coupled with flow cytometry and 16S rRNA gene amplicon pyrosequencing to enumerate and identify populations within a lake water microbial community that exhibited chemotaxis towards ammonium, nitrate and phosphate. All compounds elicited chemotactic responses from populations within the lake water, with members of Sphingobacteriales exhibiting the strongest responses to nitrate and phosphate, and representatives of the Variovorax, Actinobacteria ACK-M1 and Methylophilaceae exhibiting the strongest responses to ammonium. Our results suggest that chemotaxis towards inorganic substrates may influence the rates of biogeochemical processes. 相似文献
58.
During 2006 to 2008, the water, sediment and fish in Albasini Dam, used as a reference site outside a DDT-sprayed area, had been found to be as affected as those in the nearby DDT-sprayed area were. Accordingly, the aim of the current study, conducted in 2014, was to determine the health status of fish from Albasini Dam by means of a histology-based fish health assessment protocol. High levels of nitrates, as well as the organochlorine pesticides aldrin, dieldrin, chlordane and methoxychlor, were found in the water. Fish muscle tissue contained pesticides, including methoxychlor. A semi-quantitative histological assessment on Clarias gariepinus, Coptodon rendalli and Oreochromis mossambicus showed diverse histopathology in selected target organs, with the gills being most affected. Notably, the testis tissue of one C. rendalli was filled with eosinophilic liquid, characteristic of necrosis. Microscopic intersex was found in two of the nine O. mossambicus sampled. This is the second time that intersex as microscopic testicular oocytes has been reported in O. mossambicus in South Africa. This finding perhaps indicates that reproduction may be compromised and this will be investigated further. The presence of intersex and other histopathology in organs could be early warning signs of the declining water quality in this dam. 相似文献
59.
Critical Role of Grain Boundaries for Ion Migration in Formamidinium and Methylammonium Lead Halide Perovskite Solar Cells
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60.
Parallelized Nanopillar Perovskites for Semitransparent Solar Cells Using an Anodized Aluminum Oxide Scaffold
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Hyeok‐Chan Kwon Areum Kim Hongseuk Lee Daehee Lee Sunho Jeong Jooho Moon 《Liver Transplantation》2016,6(20)
Semitransparent solar cells have attracted significant attention for practical applications, such as windows in buildings and automobiles. Here, semitransparent, highly efficient, 1D nanostructured perovskite solar cells are demonstrated employing anodized aluminum oxide (AAO) as a scaffold layer. The parallel nanopillars in the perovskite layer enable construction of haze‐free semitransparent devices without any hysteresis behavior. By controlling the pore size in the AAO, the volume occupied by the perovskite layer can be precisely varied, and the color neutrality of the resulting devices can be achieved. With the incorporation of a transparent cathodic electrode (indium tin oxide) with a buffer layer (MoOx), a highly efficient semitransparent nanopillared perovskite solar cell is achievable with a power‐conversion efficiency of 9.6% (7.5%) and a whole device average visible light transmittance of 33.4% (41.7%). To determine the role of the scaffold layer in improving the photoelectrical properties of the cell, impedance spectroscopy analyses are performed, revealing that the AAO‐structured perovskite layer suppresses internal ion diffusion and enables critical improvements in long‐term stability under continuous illumination. 相似文献