The instrument for continuous divergent flow IEF based on our principles set and outlined previously was further extended and tested. The separation and focusing area of a trapezoidal shape had a porous bed made from a nonwoven textile material with thickness decreasing from narrow input to wide output. A narrow end was used as a single input to continuously bring a single solution into separation space with a flow rate of 0.18 mL/min. Two pairs of electrodes were positioned close to both narrow and wide ends of the separation area with equilibrium state voltage of 75 V at the narrow input and 384 V at the wide output. Under dynamic equilibrium state, the zones of both pH gradient components and analytes were separated close to the input point and focused with increasing resolution while transporting through the separation space. The long-term stability experiments had shown the suitability of the device for preparative analysis; the zones of pI markers, hemoglobin and cytochrome C remained focused and separated over 15 h with deviations from the mean focusing positions ranging from 1.26 to 3.96% of the bed output width. 相似文献
The course of oxidation of 4-aminodiphenylamine with ammonium peroxydisulfate in an acidic aqueous ethanol solution as well as the properties of the oxidation products were compared with those of 2-aminodiphenylamine. Semiconducting oligomers of 4-aminodiphenylamine and nonconducting oligomers of 2-aminodiphenylamine of weight-average molecular weights 3700 and 1900, respectively, were prepared by using an oxidant to monomer molar ratio of 1.25. When this ratio was changed from 0.5 to 2.5, the highest conductivity of oxidation products of 4-aminodiphenylamine, 2.5 x 10 (-4) S cm (-1), was reached at the molar ratio [oxidant]/[monomer] = 1.5. The mechanism of the oxidative polymerization of aminodiphenylamines has been theoretically studied by the AM1 and MNDO-PM3 semiempirical quantum chemical methods combined with the MM2 molecular mechanics force-field method and conductor-like screening model of solvation. Molecular orbital calculations revealed the prevalence of N prim-C10 coupling reaction of 4-aminodiphenylamine, while N prim-C5 is the main coupling mode between 2-aminodiphenylamine units. FTIR and Raman spectroscopic studies confirm the prevalent formation of linear N prim-C10 coupled oligomers of 4-aminodiphenylamine and suggest branching and formation of phenazine structural units in the oligomers of 2-aminodiphenylamine. The results are discussed with respect to the oxidation of aniline with ammonium peroxydisulfate, leading to polyaniline, in which 4-aminodiphenylamine is the major dimer and 2-aminodiphenylamine is the most important dimeric intermediate byproduct. 相似文献
In this paper, we classify 4-dimensional minimal CR submanifolds M of the nearly Kähler 6-sphere S6(1) which satisfy Chen's equality, i.e. , where δM(p)=τ(p)−infK(p) for every p∈M. 相似文献
Efficient separation method is a crucial part of the process in which components of highly complex biological sample are identified and characterized. Based on the principles of recently newly established electrophoretic method called divergent flow IEF (DF IEF), we have tested the DF IEF instrument which is able to operate without the use of background carrier ampholytes. We have verified that during separation and focusing of sample consisting of high numbers of proteins (yeast lysate and wheat flour extract), the pH gradient of preparative DF IEF can be created by autofocusing of the sample components themselves without any addition of carrier ampholytes. In DF IEF, the proteins are separated, desalted and concentrated in one step. The fractions of yeast lysate sample, collected at the DF IEF output and subjected to gel IEF, contained the zones of proteins gradually covering the pI values from 3.7 to 8.5. In our experimental arrangement, the highest number of proteins has been found in fractions with pI values around 5.3 as detected by polyacrylamide gel IEF with CBB staining. During DF IEF, the selected protein bands have been concentrated up to 16.8‐fold. 相似文献
Passive air sampling was undertaken using polyurethane foam passive air samplers at three types of locations, including indoors
(six offices) at buildings in the central business district (CBD) and at a private suburban home (indoor and outdoor) located
9 km from the CBD in Brisbane, Queensland, Australia. Estrogenic (E-SCREEN—MCF7-BOS) and aryl hydrocarbon receptor (AhR) (CAFLUX—H4G1.1c2)
activity were assessed for samples collected from each of these locations. The samples were tested either as crude extracts
(“untreated”) or were subjected to H2SO4 silica gel (“treated”) for each location in order to determine whether chemicals, which are not resistant to this treatment
like polycyclic aromatic hydrocarbons, potentially account for the observed activity. In most cases, H2SO4 treatment resulted in a statistically significant reduction of potency for both endpoints, suggesting that chemicals less
resistant to treatment may be responsible for much of the detected biological activity in these locations. Estrogenic potency
measurements (<0.22–185 pg m−3) were highest in the indoor offices, followed by the indoor suburban home and finally the outdoor suburban home (which was
not estrogenic). Total AhR activity for crude extracts (1.3–10 pg m−3) however was highest for the outdoor suburban home site. Levels of polycyclic aromatic hydrocarbons were monitored indoors
and outdoors at the suburban home. At that location, polycyclic aromatic hydrocarbon air concentrations were on average approximately
two times higher outdoor than indoor, while AhR potency was five times higher outdoor than indoor. No significant correlation
was found between the estrogenic and AhR activity (P = 0.88) for the sites in this study.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
Statistical and kinetic methods of modeling of polymer networks formation from pre‐prepared precursors are described and illustrated. Such precursors are characteristic of distributions of molecular weight and numbers of reactive groups of distinguishable type and reactivity, and contain branch points which get elastically active in the crosslinking stage. The examples include telechelic polymers with functionality distribution, functional copolymers composed of functional and non‐functional units and groups of different reactivity. The basics of statistical and kinetic network formation methods are outlined and their adaptation to cover the non‐uniform collection of precursor molecules as one of the components. The distributions of properties of the precursors are expressed by probability generating functions which serve as input for the crosslinking stage.
A stereoselective approach has been developed to the new sugar amino acid and potential potent turn mimic 5-O-(tert-butyldimethylsilyl)-3-deoxy-1,2-O-isopropylidene-3-methoxycarbonylamino-alpha-D-xylofuranose 3-C-carboxylic acid (12), via the [3,3]-sigmatropic rearrangement of allylic thiocyanates (Z)-6 and (E)-7, prepared from D-xylose. The synthesis of a new dipeptide 13 is also described. 相似文献
The course of aniline oxidation with ammonium peroxydisulfate in aqueous solutions has been investigated. The reaction was terminated at various times and the intermediates collected. Besides the precipitates, the films deposited in situ on silicon windows have also been studied. The kinetic course of polymerization is controlled by the acidity level, which changes during the polymerization from pH 8 to a final value close to pH 1. It has two distinct exothermic phases. Gel-permeation chromatography indicates that aniline oligomers are produced at first at high pH, while polyaniline follows after the pH becomes sufficiently low. The growth of polyaniline nanotubes was observed by optical microscopy and confirmed by electron microscopy. The molecular structure of the reaction intermediates was studied in detail by FTIR spectroscopy. Oxidation products are markedly sulfonated, and they contain phenazine units. Aniline oligomers are more soluble in chloroform than the polymer fraction, which contains nanotubes. 相似文献