This study presents the in-capillary enzymatic biotransformation of dextromethorphan, an antitusive drug and opioid receptor antagonist, and subsequent electrophoretic separation of its products. The study includes the optimization of separation parameters to fulfill the requirements of an online microreaction. The analyses were performed in a bare fused-silica capillary using 100 mM sodium tetraborate (pH 10.0) mixed with linear polyacrylamide (20%, v/v) and 2-propanol (10%, v/v). This BGE was suitable for monitoring both off-line and in-capillary incubations. The partial filling technique enabled the enzymatic reaction to be carried out in its optimal environment (20 mM sodium phosphate, pH 7.4). Finally, in-capillary microreaction in the presence of cytochrome P450 3A4 gave satisfactory outcomes. 相似文献
The bubble size distribution and void fraction (ɛg) (at two bulk liquid pool positions below the bulk liquid-foam interface and one lower foam phase position) in a continuous
foam fractionation column containing ovalbumin were obtained using a photoelectric capillary probe. The bubble size and ɛg data were gathered for different operating conditions (including the changes in the superficial gas velocity and feed flow
rate) at a feed solution of pH 6.5 and used to calculate the specific area, a, of the bubbles. Thus, local enrichment (ERl), values of ovalbumin could be estimated and compared with directly obtained experimental results. The ERl results were also correlated with the bubble size and ɛg to understand better the concentration mechanisms of foam fractionation. The high ERl in the lower foam phase was largely attributable to the abrupt increase in ɛg (from 0.25 to 0.75), or the a (from about 12 to 25 cm2/cm3) from the bulk liquid to the foam phase. These changes correspond with enhanced gravity drainage. With an increase in the
superficial gas velocity, the bubble size increased and the a decreased in both the bulk liquid and lower foam phases, resulting in a decrease in the local experimentally determined enrichments
at high superficial gas velocities. At intermediate feed flow rates, the bubble size reached the maximum. The ɛg and a, on the other hand, were the largest for the largest feed flow rate. The ERl in the lower foam phase was maximized at the lowest feed flow rate. It follows, therefore, that a alone is not sufficient to determine the magnitude of the ERl in the foam phase. 相似文献
The heating of selected [1-(η(6)-arene)-closo-1,2,3-FeC(2)B(9)H(11)] complexes resulted in the thermal rearrangement and isolation of the corresponding 1,2,4-, 1,2,7-, and 1,2,8-cage isomers. Demonstrated here is a similar rearrangement and the NMR behaviour for isostructural [1-(η(5)-cyclopentadienyl)-closo-1,2,3-CoC(2)B(9)H(11)] compounds. 相似文献
We show that every frame can be essentially embedded in a Boolean frame, and that this embedding is the maximal essential extension of the frame in the sense that it factors uniquely through any other essential extension. This extension can be realized as the embedding \(L \rightarrow \mathcal {N}(L) \rightarrow \mathcal {B}\mathcal {N}(L)\), where \(L \rightarrow \mathcal {N}(L)\) is the familiar embedding of L into its congruence frame \(\mathcal {N}(L)\), and \(\mathcal {N}(L) \rightarrow \mathcal {B}\mathcal {N}(L)\) is the Booleanization of \(\mathcal {N}(L)\). Finally, we show that for subfit frames the extension can also be realized as the embedding \(L \rightarrow {{\mathrm{S}}}_\mathfrak {c}(L)\) of L into its complete Boolean algebra \({{\mathrm{S}}}_\mathfrak {c}(L)\) of sublocales which are joins of closed sublocales. 相似文献
Driven by the demand for various cationic biopolymers in recent years, the quaternization of cellulose nanofibers was carefully investigated to have tight control over their final characteristics. The addition of sodium hydroxide (NaOH) to the reaction mixture is crucial as it catalyzes the conversion of alcohol groups of cellulose into more reactive alcoholate groups. On the other hand, excessive concentration proves to inhibit the reactivity of hydroxyl groups. The addition of glycidyltrimethylammonium chloride (GTMAC) increases the yield of the trimethylammonium chloride content (TMAC) reaction, while in excess it affects the rheological properties of the quaternizated cellulose nanofibers. The effects of NaOH and GTMAC on the TMAC content and rheological properties have been investigated in detail and mathematically evaluated. Furthermore, a comparison of the viscoelastic behavior and shear thinning character of commercial cationic micro- and nanofibrillated cellulose is presented. The research allows to extend the possibility of using cellulose in many applications of cationic biopolymers.
There are four neutralization-reionization processes which can be studied. In the first two, gaseous cations are collisionally reduced and the resulting fast neutrals are either oxidized by collisional electron removal (NR) or reduced further by collisional electron attachment (NR?). In the third and fourth processes, gaseous anions are collisionally oxidized and the resulting fast neutrals are either oxidized further by collisional electron removal (?NR) or reduced by collisional electron attachment (?NR?). These four processes are illustrated briefly using the interrelated species [SF5]+ and [SF5]?. Negative-ion-negative-ion neutralization-reionization (?NR?) processes are illustrated for [CH3O]?, [C2H5O]?, [CO3]? and [HCO3]? and compared with ?NR processes. In addition, collisional electron attachment ionization of fast neutrals formed in unimolecular fragmentation of cations is illustrated. The ?NR? studies of [CO3]? and [HCO3]? show that both CO3 and HCO3 are stable neutral species with lifetimes greater than 0.7 μs. 相似文献
From the work of Simmons about nuclei in frames it follows that a topological space X is scattered if and only if each congruence Θ on the frame of open sets is induced by a unique subspace A so that , and that the same holds without the uniqueness requirement iff X is weakly scattered (corrupt). We prove a seemingly similar but substantially different result about quasidiscrete topologies
(in which arbitrary intersections of open sets are open): each complete congruence on such a topology is induced by a subspace
if and only if the corresponding poset is (order) scattered, i.e. contains no dense chain. More questions concerning relations
between frame, complete, spatial, induced and open congruences are discussed as well.
Dedicated to Bernhard Banaschewski. 相似文献
N-coordinated Ge(II) alkoxides L1(tBuO)Ge ( 1 ), L2(tBuO)Ge ( 2 ) and [L2(OtBu)Ge ⋅ BH3] ( 4 ) were prepared. Effect of either chelating ligands L1 and L2 or Ge→B interaction on strength of the Ge−OtBu bond was studied by insertion reaction of PhNCO. As a result, the Ge(II) carbamate L2{[(tBuO)OC](Ph)N}Ge ( 3 ) was isolated. Alcoholysis exchange reactions of 1 and 2 with substituted phenols were studied to find an easy synthetic protocol for a synthesis of functionalized Ge(II) alkoxides. Reactions yielded Ge(II) alkoxides L1,2(2-Br−C6H4O)Ge ( 5 for L1, 8 for L2), L1,2(2-MeNH−C6H4O)Ge ( 6 for L1, 9 for L2), L1,2(2-Ph2P−C6H4O)Ge ( 7 for L1, 10 for L2), L2(2-Br-3-OH−C6H3O)Ge ( 11 ) and L2(2-NC5H4O)Ge ( 12 ) containing the additional polar groups Y (Y=Br, MeNH, PPh2, OH or N). Finally, phosphane decorated Ge(II) alkoxides 7 and 10 were tested as suitable ligands in reactions with (COD)W(CO)4 and BH3. As a consequence, new complexes [(κ2- 7 )W(CO)4] ( 13 ) and [L1(2-Ph2P ⋅ {BH3}-C6H4O)Ge ⋅ {BH3}] ( 14 ) were isolated. All compounds were characterized by NMR and IR spectroscopy, and compounds 3 , 4 , 9 and 11 were additionally characterized by X-ray diffraction analysis. 相似文献
In [1Han, Y., Xu, Y. (2007). Hochschild (co)homology of exterior algebras. Comm. Algebra 35(1):115–131.[Web of Science ®], [Google Scholar]], the authors computed the additive and multiplicative structure of HH*(A;A), where A is the n-th exterior algebra over a field. In this paper, we derive all their results using a different method (AMT) as well as calculate the additive structure of HHk(A;A) and HHk(A;A) over ?. We provide concise presentations of algebras HH?(A;A) and HH*(A;A) as well as determine their generators in the Hochschild complex. Finally, we compute an explicit free resolution (spanned by multisets) of the Ae-module A and describe the homotopy equivalence to its bar resolution. 相似文献