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101.
Daria Dzema Liudmila Kartsova Diana Kapizova Dietmar Appelhans 《Chromatographia》2017,80(11):1683-1693
Core–shell-type polymers based on a hyperbranched (hb) poly(ethylenimine) core and a shell with a variable maltose content were applied as coating materials for fused silica capillaries. A new, simple, fast, and reproducible way of modifying the capillary walls through the physical adsorption of the core–shell-type polymers using a Cu2+ support was developed. The coating created by this method was found to be very stable compared to the coating created using a solution of the polymer only. Capillaries modified with the core–shell-type polymers were tested by applying them to the electrophoretic separation of catecholamines and proteins. The modified capillaries showed high efficiencies (up to 800,000 theoretical plates per meter for lysozyme) and separation selectivities. The highest efficiency was achieved using capillaries modified with the polymer containing the lowest content of maltose in the shell and the most accessible positively charged core. Various online concentration techniques were also tested as a means to lower detection limits further, making it possible to analyze proteins in biological fluids (saliva) as well as catecholamines in human urine after SPE using activated alumina. 相似文献
102.
Vyacheslav Ya. Sosnovskikh Daria A. Vetyugova Alexander V. Safrygin Oleg S. Eltsov Pavel A. Slepukhin 《Mendeleev Communications》2018,28(4):434-436
2-(Ethoxalylmethyl)chromones undergo dimerization to dichromonyl derivatives of isotetronic acid in 62–89% yields on refluxing with 2,3-diaminopyridine in ethanol for 1–2 h. 相似文献
103.
Anton Zalygin Daria Solovyeva Ivan Vaskan Dr. Stephen Henry Dr. Marcel Schaefer Dr. Pavel Volynsky Dr. Alexander Tuzikov Dr. Elena Korchagina Dr. Ivan Ryzhov Dr. Alexey Nizovtsev Dr. Konstantin Mochalov Prof. Roman Efremov Dr. Eleonora Shtykova Dr. Vladimir Oleinikov Prof. Nicolai Bovin 《ChemistryOpen》2020,9(6):641-648
The synthetic function-spacer-lipid (FSL) amphiphile biotin-CMG-DOPE is widely used for delicate ligation of living cells with biotin residues under physiological conditions. Since this molecule has an “apolar-polar-hydrophobic” gemini structure, the supramolecular organization is expected to differ significantly from the classical micelle. Its organization is investigated with experimental methods and molecular dynamics simulations (MDS). Although the linear length of a single biotin-CMG-DOPE molecule is 9.5 nm, the size of the dominant supramer globule is only 14.6 nm. Investigations found that while the DOPE tails form a hydrophobic core, the polar CMG spacer folds back upon itself and predominantly places the biotin reside inside the globule or planar layer. MDS demonstrates that <10 % of biotin residues on the highly water dispersible globules and only 1 % of biotin residues in layer coatings are in an linear conformation and exposing biotin into the aqueous medium. This explains why in biotin-CMG-DOPE apolar biotin residues both in water dispersible globules and coatings on solid surfaces are still capable of interacting with streptavidin. 相似文献
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Malgorzata Zieba Daria Wieczorek Emilia Klimaszewska Anna Malysa Dobrawa Kwasniewska 《Journal of Dispersion Science and Technology》2013,34(8):1189-1196
AbstractThe purpose of the study was to applicate new synthesized zwitterionic surfactants as hair shampoo components. Hair shampoos formulated for the study contained newly synthesized sulfobetaines at a concentration of 2%. The above additives were evaluated to determine their effect on shampoo dynamic viscosity, texture, yield stress, foaming properties and surface tension of aqueous shampoo solutions. The viscosity of the sulfobetaine-enriched hair shampoos ranged between 6,000 and 21,000?mPa·s, which ensures the required application properties of the formulated products. The yield stress in three prototypical shampoos was equal to approximately 10?Pa, which represents the minimum value that should characterize cosmetics of this type. The sulfobetaines added to the formulations were not found to significantly affect the parameters of hardness and adhesive force. All the formulations under study, except for the shampoo containing N-dodecyl-N-piperidinium-1-propanesulfonate, exhibited good foaming properties. The incorporation of sulfobetaines into hair shampoos contributes to an effective decrease in the surface tension of their aqueous solutions, which may indicate beneficial washing properties. The use of the proposed sulfobetaines in hair shampoos favorably modifies their physicochemical and functional properties. The findings of the study can provide useful insights for the formulation of hair shampoos containing zwitterionic surfactants. 相似文献
109.
Henryk Bem Ewa Maria Bem Joanna Krawczyk Marcin Płotek Sławomira Janiak Daria Mazurek 《Journal of Radioanalytical and Nuclear Chemistry》2013,295(3):2229-2232
Plastic PicoRad detectors with activated charcoal have been used for radon monitoring in local kindergartens and schools in two cities, Kalisz and Ostrów Wielkopolski, in the region of Greater Poland. Detectors were exposed for a standard time of 48 h during the autumn and winter of 2011 in 103 rooms (Kalisz) and 55 rooms (Ostrów Wlkp), respectively. The detectors were calibrated in the certified radon chamber of the Central Laboratory for Radiological Protection in Warsaw, Poland. The arithmetic and geometric means of indoor radon concentrations in the examined rooms were 46.0 and 30.3 Bq/m3 for Kalisz and 48.9 and 29.8 Bq/m3 for Ostrów Wlkp, respectively. The measured levels of the indoor radon concentrations were relatively low, since the main source of indoor radon for these low storey (max. three storeys) buildings is radon escaping from the underlying soil with a low 226Ra concentration (~15 Bq/m3). Therefore, the calculated annual effective doses from that source for the children in Kalisz and Ostrów Wlkp were also low 0.35 mSv. 相似文献
110.
Tatiana S. Yankova Natalia A. Chumakova Daria A. Pomogailo Andrey Kh. Vorobiev 《Liquid crystals》2013,40(8):1135-1145
Orientational order of guest molecules in aligned liquid crystal 4-cyano-4′-pentylbiphenyl (5CB) is studied via optical dichroism and electron paramagnetic resonance (EPR) spectra measurements. The guest molecules used are bifunctional molecules bearing paramagnetic nitroxide group and photochromic azobenzene moiety. The bifunctional probe with rigidly bonded nitroxide and azobenzene moieties was found to align as a whole, while flexible long spacer between the moieties provides independent alignment for the nitroxide and azobenzene parts. Intermolecular interactions responsible for the alignment of azobenzene and nitroxide moieties of the probe molecules are discussed. The molecules with cis-configuration of azobenzene moiety are able to align in the liquid-crystalline medium, but to a lesser extent than the molecules with trans-configuration. Directions of orientational axes and characteristics of rotational mobility of spin probes are determined. Second, fourth and, in some cases, sixth rank order parameter values are found. 相似文献