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排序方式: 共有538条查询结果,搜索用时 15 毫秒
191.
Reiter EV Dutton MF Agus A Nordkvist E Mwanza MF Njobeh PB Prawano D Häggblom P Razzazi-Fazeli E Zentek J Andersson MG 《The Analyst》2011,136(19):4059-4069
The duplicate method for estimating uncertainty from measurement including sampling is presented in the Eurachem/CITAC guide. The applicability of this method as a tool for verifying sampling plans for mycotoxins was assessed in three case studies with aflatoxin B(1) in animal feedingstuffs. Aspects considered included strategies for obtaining samples from contaminated lots, assumptions about distributions, approaches for statistical analysis, log(10)-transformation of test data and applicability of uncertainty estimates. The results showed that when duplicate aggregate samples are formed by interpenetrating sampling, repeated measurements from a lot can be assumed to approximately follow a normal or lognormal distribution. Due to the large variation in toxin concentration between sampling targets and sometimes very large uncertainty arising from sampling and sample preparation (U(rel) ≥ 50%), estimation of uncertainty from log(10)-transformed data was found to be a more generally applicable approach than application of robust ANOVA. 相似文献
192.
Wang E Ma Z Zhang Z Vandewal K Henriksson P Inganäs O Zhang F Andersson MR 《Journal of the American Chemical Society》2011,133(36):14244-14247
A new, low-band-gap alternating copolymer consisting of terthiophene and isoindigo has been designed and synthesized. Solar cells based on this polymer and PC(71)BM show a power conversion efficiency of 6.3%, which is a record for polymer solar cells based on a polymer with an optical band gap below 1.5 eV. This work demonstrates the great potential of isoindigo moieties as electron-deficient units for building donor-acceptor-type polymers for high-performance polymer solar cells. 相似文献
193.
Two straightforward and convenient routes for the synthesis of the antimalarial agents FR900098 and fosmidomycin are described. In the key steps N- or P-alkylation reactions are used. The best overall yields of FR900098 and fosmidomycin in 15 mmol scale are 83% and 68%, respectively. These routes utilize readily available materials and avoid harsh conditions. 相似文献
194.
Shadi Jafarzadeh Mats Johansson Per‐Erik Sundell Mauro Claudino Jinshan Pan Per M. Claesson 《先进技术聚合物》2013,24(7):668-678
Composites of nanostructured polyaniline (PANI) conducting polymer in a polyester acrylate (PEA) formulation were made to provide conductive organic coatings. The effect of the presence and amount of PANI on the photocuring performance of the ultraviolet (UV)‐curable acrylate system has been investigated employing real‐time Fourier transform infrared spectroscopy as the main technique. Longer initial retardation of the radical polymerization and lower rates of cross‐linking reactions were observed for dispersions containing PANI of higher than 3wt.%. The PEA/PANI samples were more affected than the neat PEA resin by the changes in UV light intensity and oxygen accessibility during UV curing. Samples with higher PANI content, of up to 10wt.%, were tested and could be partially cured even at UV light intensities as low as 2 mW cm?2 when the oxygen replenishment into the system was inhibited. Thermal analysis revealed that the presence of PANI did not induce any significant change in Tg of the cured system, meaning that early decrease in mobility and vitrification is not the reason for lower ultimate conversion of the dispersions with higher PANI content compared with the neat PEA resin. Curing under strong UV lamps, of 1.5 W cm?2 intensity, made it possible to reach high degrees of conversion on films with similar mechanical properties independent of the PANI content. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
195.
Yangguang Ou Juanfang Wu Mats Sandberg Stephen G. Weber 《Analytical and bioanalytical chemistry》2014,406(26):6455-6468
This review covers recent advances in sampling fluid from the extracellular space of brain tissue by electroosmosis (EO). Two techniques, EO sampling with a single fused-silica capillary and EO push–pull perfusion, have been developed. These tools were used to investigate the function of membrane-bound enzymes with outward-facing active sites, or ectoenzymes, in modulating the activity of the neuropeptides leu-enkephalin and galanin in organotypic-hippocampal-slice cultures (OHSCs). In addition, the approach was used to determine the endogenous concentration of a thiol, cysteamine, in OHSCs. We have also investigated the degradation of coenzyme A in the extracellular space. The approach provides information on ectoenzyme activity, including Michaelis constants, in tissue, which, as far as we are aware, has not been done before. On the basis of computational evidence, EO push–pull perfusion can distinguish ectoenzyme activity with a ~100 μm spatial resolution, which is important for studies of enzyme kinetics in adjacent regions of the rat hippocampus. Graphical Abstract
196.
Sanjay R Borhade Ulrika Rosenstr?m Jonas S?vmarker Thomas Lundb?ck Annika Jenmalm-Jensen Kristmundur Sigmundsson Hanna Axelsson Fredrik Svensson Vivek Konda Christian Sk?ld Mats Larhed Mathias Hallberg 《ChemistryOpen》2014,3(6):256-263
The inhibition of insulin-regulated aminopeptidase (IRAP, EC 3.4.11.3) by angiotenesin IV is known to improve memory and learning in rats. Screening 10 500 low-molecular-weight compounds in an enzyme inhibition assay with IRAP from Chinese Hamster Ovary (CHO) cells provided an arylsulfonamide (N-(3-(1H-tetrazol-5-yl)phenyl)-4-bromo-5-chlorothiophene-2-sulfonamide), comprising a tetrazole in the meta position of the aromatic ring, as a hit. Analogues of this hit were synthesized, and their inhibitory capacities were determined. A small structure–activity relationship study revealed that the sulfonamide function and the tetrazole ring are crucial for IRAP inhibition. The inhibitors exhibited a moderate inhibitory potency with an IC50=1.1±0.5 μm for the best inhibitor in the series. Further optimization of this new class of IRAP inhibitors is required to make them attractive as research tools and as potential cognitive enhancers. 相似文献
197.
Mats Andersson 《Mathematische Zeitschrift》2006,254(2):315-332
Let f be a r×m-matrix of holomorphic functions that is generically surjective. We provide explicit integral representation of holomorphic
ψ such that ϕ=f
ψ, provided that ϕ is holomorphic and annihilates a certain residue current with support on the set where f is not surjective. We also consider formulas for interpolation. As applications we obtain generalizations of various results
previously known for the case r=1.
The author was partially supported by the Swedish Research Council 相似文献
198.
Mats Weibull H. Weller Hefelmann P. V. P. Berg M. Gruber Meissl G. Denigès Kirchner und Schäffer 《Fresenius' Journal of Analytical Chemistry》1896,35(1):102-104
Ohne Zusammenfassung 相似文献
199.
This was a cross-sectional study based on material representing the Swedish work-force from a survey conducted in 1999, 2001 and 2003 by Statistics Sweden. Exposure to whole body vibration (WBV) was prevalent among agricultural, forestry, fishery workers and among plant and machinery operators based on a sample of 40,000 employed persons. Approximately 70% responders, that are 9798 persons answered both the interview and the questionnaire for the analysis of exposure-response. Exposure to WBV at least half the working time was associated with prevalence ratios above two for musculoskeletal symptoms in the low back, neck, shoulder/arm and hand among workers. When the exposure factors lifting and frequent bending were added to a multivariate analysis, surprisingly the magnitude of association was low between low back symptoms and WBV exposure. Interestingly, the relation between WBV exposure and symptoms in the neck, shoulder/arm and hand had the same or higher magnitude of association even when the possible confounders were in the model. For the neck, low back and shoulder/arm there was a visible increase in prevalence ratio (as high as 5 times) when combined exposures of WBV, lifting, frequent bending, twisted posture and noise were included in the analysis. 相似文献
200.
Antonio Cravino Gerald Zerza Michele Maggini Stefania Bucella Mattias Svensson Mats R. Andersson Helmut Neugebauer Christoph J. Brabec N. Serdar Sariciftci 《Monatshefte für Chemie / Chemical Monthly》2003,134(4):519-527
Summary. We report the synthesis and the spectroscopic properties of a novel soluble thiophene-based copolymer carrying pendant fullerene
moieties (donor–acceptor double-cable polymer). Photoinduced absorption (PIA) experiments on spin cast films reveal a photoinduced
electron transfer from the polythiophene chain onto the fullerene moieties. The performance of photovoltaic devices produced
with this copolymer is also discussed.
Corresponding author. E-mail: antonio.cravino@jku.at
Received August 16, 2002; accepted (revised) August 26, 2002 相似文献