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Regina C. Fischer R. Wittlinger K. Ballschmiter 《Fresenius' Journal of Analytical Chemistry》1992,342(4-5):421-425
Summary Vapor pressures for 133 individual polychlorobiphenyl congeners as subcooled liquids were determined by two different approaches on the basis of gas-chromatographic retention indices obtained with two different non-polar stationary phases. The approach which is based on the retention indices obtained on a methyl-50% octyl polysiloxane phase (SB Octyl 50) and on reference vapor pressures of PCB congeners, and thus contains less approximations, should yield more accurate results than the method which uses retention indices obtained on a methyl polysiloxane phase (OV 101) and reference vapor pressure data taken from the n-alkanes of the retention index system. A systematic deviation is observed between the values obtained by the two different methods. The first method gives constantly slightly higher values for the vapor pressure. This will be caused by the different separation characteristics of the two non-polar stationary phases used, as well as by uncertainties in the reference data for the vapor pressure calculations. 相似文献
124.
A mathematical puzzle that asks about “missing” area leads to an exploration of the Fibonacci sequence as well as genuine inquiry in plane geometry connected to algebra. This article discusses the inquiry, the concepts, the solution, and an extension that deepens all students’ understanding of connections between algebra and geometry. 相似文献
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One hundred consumers evaluated three types of set yoghurt made from: 100% pressure treated milk (PTM; 600 MPa for 15 min), 100% heat treated milk (HTM; 85 °C for 20 min) and a mixture containing 10% PTM and 90% HTM. There was no significant difference between appearance liking or texture liking of the three yoghurt types, though the texture score of PTM yoghurt and mixed milk yoghurt were both higher than HTM yoghurt. Creaminess score for PTM yoghurt was significantly higher than for HTM yoghurt; mixed milk yoghurt was significantly different from HTM yoghurt but not from PTM yoghurt. Concerning taste liking, PTM yoghurt scored significantly less than mixed milk yoghurt, with HTM yoghurt between these two. 57% of consumers preferred the HTM to PTM yoghurt, giving taste as their main criteria; those preferring PTM yoghurt based their choice on texture. Rheological assessments showed differences in gel structure, which justify consumer texture and creaminess choices. 相似文献
127.
Cynthia Regina Albrecht Mahl Rogrio Aparecido Bataglioli Guilherme Bedeschi Calais Thiago Bezerra Taketa Marisa Masumi Beppu 《Molecules (Basel, Switzerland)》2022,27(23)
The anomalous interaction between metal ions and the peptide beta-amyloid is one of the hallmarks of Alzheimer’s disease. Metal-binding biopolymers, including polysaccharides, can elucidate the fundamental aspects of metal ions’ interactions with biological tissue and their interplay in Alzheimer’s disease. This work focuses on the role of the alginate composition on Cu(II) adsorption in the presence of histidine or β-amyloid, the peptide associated with the progression of Alzheimer’s disease. Alginate samples with different mannuronic/guluronic (M/G) ratios led to similar Cu(II) adsorption capacities, following the Langmuir isotherm and the pseudo-second-order adsorption kinetic models. Although the presence of histidine produced up to a 20% reduction in the copper adsorption capacity in guluronic-rich alginate samples (M/G~0.61), they presented stable bidentate chelation of the metallic ion. Chemical analyses (FTIR and XPS) demonstrated the role of hydroxyl and carboxyl groups in copper ion chelation, whereas both crystallinity and morphology analyses indicated the prevalence of histidine interaction with guluronic-rich alginate. Similar results were observed for Cu(II) adsorption in alginate beads in the presence of beta-amyloid and histidine, suggesting that the alginate/histidine system is a simple yet representative model to probe the application of biopolymers to metal ion uptake in the presence of biological competitors. 相似文献
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Regina Janciene Ausra Vektariene Zita Stumbreviciute Lidija Kosychova Algirdas Klimavicius Benedikta D. Puodziunaite 《Heteroatom Chemistry》2004,15(5):363-368
The novel 4H‐thiazolo[3,2‐d][1,5]benzodiazepinium salts have been synthesized in a single step by the reaction of the variously substituted 2,3,4,5‐tetrahydro‐1,5‐benzodiazepine‐2(1H)‐thiones and bromoacetaldehyde diethyl acetal. Cyclization is obviously influenced by the nature of the substituents in the benzodiazepine system. Theoretical modeling and B3LYP DFT computational studies are presented. © 2004 Wiley Periodicals, Inc. Heteroatom Chem 15:363–368, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20026 相似文献
130.
Y. Funaki A. Tohsaki H. Horiuchi P. Schuck G. Röpke 《The European Physical Journal A - Hadrons and Nuclei》2006,28(3):259-263
In order to discuss the spatial extention of the 02
+-state of 12C (Hoyle state), we analyze the inelastic form factor of electron scattering to the Hoyle state, which our 3α-condensate wave
function reproduces very well like previous 3α RGM/GCM models. The analysis is made by varying the size of the Hoyle state
artificially. As a result, we find that only the maximum value of the form factor sensitively depends on its size, while the
positions of maximum and minimum are almost unchanged. This size dependence is found to come from a characteristic feature
of the transition density from the ground state to the Hoyle state. We further show the theoretical predictions of the inelastic
form factor to the 22
+-state of 12C, which was recently observed above the Hoyle state, and of the inelastic form factor to the calculated 03
+-state of 16O, which was conjectured to correspond to the 4α condensed state in previous theoretical work by the present authors. 相似文献