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排序方式: 共有89条查询结果,搜索用时 15 毫秒
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2.
Shuai Wang Jon Hovland Steven Brooks Rune Bakke 《Applied biochemistry and biotechnology》2014,172(2):776-783
The decrease in toxicity of carbon capture reclaimer monoethanolamine (MEA) waste (MEAw) during anaerobic degradation of such waste together with easily degradable organics was investigated. Samples were collected from a bioreactor at steady state with 86 % organic chemical oxygen demand removal at room temperature, which had been running on MEAw for 2 years. The toxicity of the digester effluents were 126, 42 and 10 times lower than that of the MEAw to the tested freshwater trophic groups of Pseudokirchneriella subcapitata, Daphnia magna and embryos of Danio rerio, respectively. The toxicity of the tested taxonomic groups after anaerobic digestion was mainly attributed to the ammonia generated by the degradation of MEAw. 相似文献
3.
Zellner M Winkler W Hayden H Diestinger M Eliasen M Gesslbauer B Miller I Chang M Kungl A Roth E Oehler R 《Electrophoresis》2005,26(12):2481-2489
For the preparation of proteins for proteome analysis, precipitation is frequently used to concentrate proteins and to remove interfering compounds. Various methods for protein precipitation are applied, which rely on different chemical principles. This study compares the changes in the protein composition of human blood platelet extracts after precipitation with ethanol (EtOH) or trichloroacetic acid (TCA). Both methods yielded the same amount of proteins from the platelet preparations. However, the EtOH-precipitated samples had to be dialyzed because of the considerable salt content. To characterize single platelet proteins, samples were analyzed by two-dimensional fluorescence differential gel electrophoresis. More than 90% of all the spots were equally present in the EtOH- and TCA-precipitated samples. However, both precipitation methods showed a smaller correlation with nonprecipitated samples (EtOH 74.9%, TCA 79.2%). Several proteins were either reduced or relatively enriched in the precipitated samples. The proteins varied randomly in molecular weight and isoelectric point. This study shows that protein precipitation leads to specific changes in the protein composition of proteomics samples. This depends more on the specific structure of the protein than on the precipitating agent used in the experiment. 相似文献
4.
Seidler-Egdal RK Johansson FB Veltzé S Skou EM Bond AD McKenzie CJ 《Dalton transactions (Cambridge, England : 2003)》2011,40(13):3336-3345
A comparison of the electrochemical properties of a series of dinuclear complexes [M(2)(L)(RCO(2))(2)](+) with M = Mn or Co, L = 2,6-bis(N,N-bis-(2-pyridylmethyl)-sulfonamido)-4-methylphenolato (bpsmp(-)) or 2,6-bis(N,N-bis(2-pyridylmethyl)aminomethyl)-4-tert-butylphenolato (bpbp(-)) and R = H, CH(3), CF(3) or 3,4-dimethoxybenzoate demonstrates: (i) The electron-withdrawing sulfonyl groups in the backbone of bpsmp(-) stabilize the [M(2)(bpsmp)(RCO(2))(2)](+) complexes in their M(II)(2) oxidation state compared to their [M(2)(bpbp)(RCO(2))(2)](+) analogues. Manganese complexes are stabilised by approximately 550 mV and cobalt complexes by 650 mV. (ii) The auxiliary bridging carboxylato ligands further attenuate the metal-based redox chemistry. Substitution of two acetato for two trifluoroacetato ligands shifts redox couples by 300-400 mV. Within the working potential window, reversible or quasi-reversible M(II)M(III)? M(II)(2) processes range from 0.31 to 1.41 V for the [Co(2)(L)(RCO(2))(2)](+/2+) complexes and from 0.54 to 1.41 V for the [Mn(2)(L)(RCO(2))(2)](+/2+) complexes versus Ag/AgCl for E(M(II)M(III)/M(II)(2)). The extreme limits are defined by the complexes [M(2)(bpbp)(CH(3)CO(2))(2)](+) and [M(2)(bpsmp)(CF(3)CO(2))(2)](+) for both metal ions. Thus, tuning the ligand field in these dinuclear complexes makes possible a range of around 0.9 V and 1.49 V for the one-electron E(M(II)M(III)/M(II)(2)) couple of the Mn and Co complexes, respectively. The second one-electron process, M(II)M(III)? M(III)(2) was also observed in some cases. The lowest potential recorded for the E°(M(III)(2)/M(II)M(III)) couple was 0.63 V for [Co(2)(bpbp)(CH(3)CO(2))(2)](2+) and the highest measurable potential was 2.23 V versus Ag/AgCl for [Co(2)(bpsmp)(CF(3)CO(2))(2)](2+). 相似文献
5.
Nasser E. Bastani Thomas E. Gundersen Rune Blomhoff 《Rapid communications in mass spectrometry : RCM》2009,23(18):2885-2890
F2‐isoprostanes are a family of prostaglandin F2‐like compounds that are formed by free‐radical‐catalyzed peroxidation of arachidonic acid. Several F2‐isoprostanes, but in particular 8‐epi PGF2α, are widely used as oxidative stress biomarkers. An analytical method based on liquid chromatography with negative electrospray ionization (ESI) coupled to tandem mass spectrometric detection (LC/MS/MS) was developed for the determination of 8‐epi PGF2α concentrations in human plasma, whole blood, erythrocytes and urine. 8‐epi PGF2α‐d4, a stable isotope derivative of 8‐epi PGF2α, was used as an internal standard (IS). A 50 µL sample was focused on‐column and separated on two 3 µm particle size SUPELCOSIL? ABZ+Plus HPLC columns (15 cm × 4.6 mm and 7.5 cm × 4.6 mm) connected in series. An Applied Biosystems 4000 Q TRAP LC/MS/MS system with ESI was operated in multiple reaction monitoring (MRM) mode with the precursor‐to‐product ion transitions m/z 353.4 → 193.1 (8‐epi PGF2α), 357.4 → 197.1 (8‐epi PGF2α‐d4), used for quantification. The assay was fully validated and found to have adequate accuracy, precision, linearity, sensitivity and selectivity. The mass limit of detection (mLOD) was 1 pg of analyte eluting from the column. The assay has been successfully applied to the analysis of human plasma, whole blood, erythrocytes and urine samples. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
6.
A multiblock/multilevel algorithm with local refinement for general two‐ and three‐dimensional fluid flow is presented. The patched‐based local refinement procedure is presented in detail and algorithmic implementations are also presented. The multiblock implementation is essentially block‐unstructured, i.e. each block having its own local curvilinear co‐ordinate system. Refined grid patches can be put anywhere in the computational domain and can extend across block boundaries. To simplify the implementation, while still maintaining sufficient generality, the refinement is restricted to a refinement of the grid successively halving the grid size within a selected patch. The multiblock approach is implemented within the framework of the well‐known SIMPLE solution strategy. Computational experiments showing the effect of using the multilevel solution procedure are presented for a sample elliptic problem and a few benchmark problems of computational fluid dynamics (CFD). Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
7.
Lausten R Smirnova O Sussman BJ Gräfe S Mouritzen AS Stolow A 《The Journal of chemical physics》2008,128(24):244310
In general, many different diagrams can contribute to the signal measured in broadband four-wave mixing experiments. Care must therefore be taken when designing an experiment to be sensitive to only the desired diagram by taking advantage of phase matching, pulse timing, sequence, and the wavelengths employed. We use sub-25 fs pulses to create and monitor vibrational wavepackets in gaseous iodine, bromine, and iodine bromide through time- and frequency-resolved femtosecond coherent anti-Stokes Raman scattering (CARS) spectroscopy. We experimentally illustrate this using iodine, where the broad bandwidths of our pulses, and Boltzmann population in the lower three vibrational levels conspire to make a single diagram dominant in one spectral region of the signal spectrum. In another spectral region, however, the signal is the sum of two almost equally contributing diagrams, making it difficult to directly extract information about the molecular dynamics. We derive simple analytical expressions for the time- and frequency-resolved CARS signal to study the interplay of different diagrams. Expressions are given for all five diagrams which can contribute to the CARS signal in our case. 相似文献
8.
Lars Sørensen Rune Salbo 《Journal of the American Society for Mass Spectrometry》2018,29(11):2278-2281
Hydrogen deuterium exchange measured by mass spectrometry (HDX-MS) is a commonly used technique for studying the structural dynamics of proteins in solution. The first part of any bottom-up HDX-MS experiment is to identify the peptides generated from a digestion step. This requires manual inspection of the identified peptides to determine their use for HDX-MS analysis, which is a time-consuming task. Throughout the literature, there have been different approaches for removing peptides that do not yield quantifiable HDX information. This includes using validity scores from the software used in the generation of the peptide map and that the peptide should be found in two out of three technical replicate experiments. Here, we analyze the previously available methods for filtering the identified peptides in regard to their ability to predict whether a peptide will provide quantifiable HDX-MS data or not. We also present a new score-based system relying on a combination of MS/MS parameters that offers an improved method for separating quantifiable peptides from the nonquantifiable. Using this score-based method reduces the number of peptide spectra that needs to be manually inspected and thereby the time spent curating HDX-MS data. 相似文献
9.
Severinsen R Bourne GT Tran TT Ankersen M Begtrup M Smythe ML 《Journal of combinatorial chemistry》2008,10(4):557-566
A biphenyl privileged structure library containing three attachment points were synthesized using a catechol-based safety-catch linker strategy. The method requires the attachment of a bromo-acid to the linker, followed by a Pd-catalyzed Suzuki cross-coupling reaction. Further derivatization, activation of the linker with strong acid and aminolysis afforded the respective products in high purity and good overall yield. To show the versatility of the synthesis, a 199-member library was generated. The library samples both conformational and chemical diversity about a well-known privileged substructure. 相似文献
10.
Dr. Lars Michael Skjolding Dr. Sara Nørgaard Sørensen Dr. Nanna Bloch Hartmann M. Sc. Rune Hjorth Dr. Steffen Foss Hansen Dr. Anders Baun 《Angewandte Chemie (International ed. in English)》2016,55(49):15224-15239
The number of products on the market containing engineered nanoparticles (ENPs) has increased significantly, and concerns have been raised regarding their ecotoxicological effects. Environmental safety assessments as well as relevant and reliable ecotoxicological data are required for the safe and sustainable use of ENPs. Although the number of publications on the ecotoxicological effects and uptake of ENPs is rapidly expanding, the applicability of the reported data for hazard assessment is questionable. A major knowledge gap is whether nanoparticle effects occur when test organisms are exposed to ENPs in aquatic test systems. Filling this gap is not straightforward, because of the broad range of ENPs and the different behavior of ENPs compared to “ordinary” (dissolved) chemicals in the ecotoxicity test systems. The risk of generating false negatives, and false positives, in the currently used tests is high, and in most cases difficult to assess. This Review outlines some of the pitfalls in the aquatic toxicity testing of ENPs which may lead to misinterpretation of test results. Response types are also proposed to reveal potential nanoparticle effects in the aquatic test organisms. 相似文献