Recent advances in understanding the role and application of bacteria to the remediation of toxic metal and radionuclide contaminated terrestrial environments have come from several avenues. Novel ...species capable of mobilization and immobilization of metal ions have been discovered. Remediation of toxicity has been accelerated by nutrient amendment, the use of chelating agents and novel methods for phosphate amendment. Major advances in the use of natural and genetically engineered species for bioprotection and remediation of organic co-contaminants have been reported. Construction of wetland function continues to be developed for containment and decontamination of wastewaters.
A combination of soft X-ray absorption spectroscopy (XAS) measurements and StoBe density functional theory (DFT) calculations has been used to study the electronic structures of the ferrocene-labeled ...peptides Fc-Pro n -OBz (n = 1−4). Excellent agreement between the measured and the simulated data is observed in all cases, and the origin of all major spectral features was assigned. The breaking of the degeneracy of the ferrocene 3e2u-like unoccupied molecular orbital under the influence of a substituent attached to a Cp ring was observed experimentally. The influence of the bonding environment on the O 1s and N 1s XAS spectra was examined. A corrected assignment of one of the major features in the Fe 2p XAS spectra of ferrocene is proposed and supported by the DFT simulations, as well as the measured spectra.
Synthesis of Pandamarilactone‑1 Seah, Kang Yee; Macnaughton, Sarah J; Dallimore, Jonathan W. P ...
Organic letters,
02/2014, Letnik:
16, Številka:
3
Journal Article
Recenzirano
Odprti dostop
The first total synthesis of pandamarilactone-1, an alkaloid of Pandanus amaryllifolius, is reported. The nine-step synthesis features furan oxidation with singlet oxygen and then ...spiro-N,O-acetalization and elimination to generate the natural product and further Pandanus alkaloids, pandamarilactonines A–D.
We present a comparison between experimental and theoretical X-ray absorption spectroscopy (XAS) and X-ray emission spectroscopy (XES) of 5-fluorouracil compounds, with an emphasis on the effects of ...the inclusion of nickel in the structure. By focusing on the 1s thresholds of carbon, nitrogen, oxygen, and fluorine it was possible to provide a complete picture of the occupied and unoccupied partial density of states of the 5-fluorouracil systems. Spectra calculated using density functional theory are compared to experimental results. Most experimental results agree well with our theoretical calculations for the XAS and XES of the compounds. All spectral features are assigned. Our results reveal that the nickel in the compound is coordinated with the nitrogen sites of the 5-fluorouracil ligands.
Supercritical fluid extraction is a potential technique for the purification of pharmaceutical products containing residual solvents. The solubilities of the drugs in supercritical carbon dioxide are ...being measured as part of a program in which the potential applications of this technology are being investigated. The solubilities of three inhibitors of inflammatory activity, Ketoprofen, Piroxicam, and Nimesulide, in supercritical CO2, measured using a dynamic saturation technique, are reported at pressures between 100 bar and 220 bar and at two temperatures: 312.5 K and 331.5 K. These chemicals have relatively high solubilities with values ranging from 4 × 10-6 to 15 × 10-4 mole fraction. The solubilities exhibit a clear dependence on the solvent density, and this has been used to provide a simple and precise correlation of the data.
Numerous studies have established a relationship between soil, sediment, surface biofilm and subsurface contaminant pollution and a marked impact on the in situ microbial community in both microcosms ...and in the field. The impact of pollution on the in situ microbial community can now be quantitatively measured by molecular `fingerprinting' using `signature' biomarkers. Such molecular fingerprinting methods can replace classical microbiological techniques that relied on isolation and subsequent growth of specific microbes from the in situ microbial community. Classical methods often revealed less than 1% of the extant microbial communities. Molecular fingerprinting provides a quantitative measure of the in situ viable microbial biomass, community composition, nutritional status, relative frequency of specific functional genes, nucleic acid polymers of specific microbes, and, in some cases, the community metabolic activity can be inferred. Current research is directed at establishing correlations between contaminant disappearance, diminution in toxicity, and the return of the viable biomass, community composition, nutritional status, gene patterns of the in situ microbial community towards that of the uncontaminated soil, sediment or subsurface material with the original uncontaminated microniche environments. Compared to the current reliance on disappearance of pollutants and associated potentially toxic products for detection of effective and quantitative bioremediation, assessment of the in situ microbial community will be an additional and possibly more convincing risk assessment tool. The living community tends to accumulate and replicate toxic insults through multiple interactions within the community, which may then effect viable biomass, community composition, nutritional status, community metabolic activities, and specific nucleic acid polymer patterns.
In this paper, we describe an empirical approach to model community structure using phylogenetic signals. That approach combines information about the species (i.e. traits and phylogeny) with ...information about the habitat (i.e. environmental conditions and spatial distribution of sampling sites) and their interactions to predict the species responses (e.g. the local densities). As an application, we use the approach to model fish densities in rivers. In the model, the different species and size classes were described using a functional trait, body length, and phylogenetic eigenvectors maps whereas the sites were described using water velocity, depth, substrate composition, macrophyte cover, degree‐days, total phosphorus, and spatial eigenvector maps. The model (estimated using a regularised Poisson‐family generalised linear modelling approach) fitted the data well (likelihood‐based R2adj = 0.512) and showed fair predictive power (likelihood‐based cross‐validation R2 = 0.283) to predict the density of fish pertaining to 48 species totalling 143 combinations of species and size classes in 15 unregulated Canadian rivers. Using the model as a baseline to estimate the effect of flow regulation on community composition, we found that, with few exceptions, the densities of most fish species were lower in regulated than in unregulated rivers. Phylogenetics have been proposed to study community structure, but this is, to our knowledge, the first time phylogenetic information is used explicitly for numerical habitat modelling. We expect that models of that type will be in increasing demand now that development projects are routinely assessed through impact studies.
We present a new measurement of the Cabibbo-Kobayashi-Maskawa matrix element |Vcb| from B0→D*−ℓ+νℓ decays, reconstructed with the full Belle data set of 711 fb−1 integrated luminosity. Two form ...factor parametrizations, originally conceived by the Caprini-Lellouch-Neubert (CLN) and the Boyd, Grinstein and Lebed (BGL) groups, are used to extract the product F(1)ηEW|Vcb| and the decay form factors, where F(1) is the normalization factor and ηEW is a small electroweak correction. In the CLN parametrization we find F(1)ηEW|Vcb|=(35.06±0.15±0.56)×10−3, ρ2=1.106±0.031±0.007, R1(1)=1.229±0.028±0.009, R2(1)=0.852±0.021±0.006. For the BGL parametrization we obtain F(1)ηEW|Vcb|=(34.93±0.23±0.59)×10−3, which is consistent with the world average when correcting for F(1)ηEW. The branching fraction of B0→D*−ℓ+νℓ is measured to be B(B0→D*−ℓ+νℓ)=(4.90±0.02±0.16)%. We also present a new test of lepton flavor universality violation in semileptonic B decays, B(B0→D*−e+ν)B(B0→D*−μ+ν)=1.01±0.01±0.03. The errors quoted correspond to the statistical and systematic uncertainties, respectively. This is the most precise measurement of F(1)ηEW|Vcb| and form factors to date and the first experimental study of the BGL form factor parametrization in an experimental measurement.
Aerobically grown enrichment cultures derived from hydrocarbon-contaminated seawater and freshwater sediments were generated by growth on crude oil as sole carbon source. Both cultures displayed a ...high rate of degradation for a wide range of hydrocarbon compounds. The bacterial species composition of these cultures was investigated by PCR of the 16S rDNA gene using multiple primer combinations. Near full-length 16S rDNA clone libraries were generated and screened by restriction analysis prior to sequence analysis. Polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) was carried out using two other PCR primer sets targeting either the V3 or V6–V8 regions, and sequences derived from prominent DGGE bands were compared to sequences obtained via cloning. All data sets suggested that the seawater culture was dominated by α-subgroup proteobacteria, whereas the freshwater culture was dominated by members of the β- and γ-proteobacteria. However, the V6–V8 primer pair was deficient in the recovery of
Sphingomonas-like 16S rDNA due to a 3′ terminal mismatch with the reverse primer. Most 16S rDNA sequences recovered from the marine enrichment were not closely related to genera containing known oil-degrading organisms, although some were detected. All methods suggested that the freshwater enrichment was dominated by genera containing known hydrocarbon-degrading species.
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