An algorithm for environmental map construction is suggested based on the comparative analysis of the relationships between environmental factors and categories of biota, the integral measure of ...consistency between random events and the measure of similarity between descriptive sets being used. For probability measures, the variance formulae are given. A fragment of an environmental map is constructed for the given region of the taiga ecosystem.
The structure and properties of supramolecular complexes of α-chymotrypsin with hydroxyl-containing alkyl ammonium gemini surfactants (GSs) — α,ω-alkanedyl-bis(hydroxyethylmethylcetyl ammonium ...dibromides), with a polymethylene spacer of varying length have been studied. IR spectroscopy and tryptophan fluorescence data show that the interaction of GSs with α-chymotrypsin leads to changes of different intensity in the structural state of proteins. The most probable complexation mode of enzyme with GSs have been proposed by the molecular docking method. A correlation is found between the activity of α-chymotrypsin and the length of the GS spacer moiety. The enzyme activity correlates with the change in the substrate concentration in the aqueous phase of the surfactant micellar solution.
Micellization in sodium deoxycholate solutions Bogdanova, L. R.; Gnezdilov, O. I.; Idiyatullin, B. Z. ...
Colloid journal of the Russian Academy of Sciences,
02/2012, Letnik:
74, Številka:
1
Journal Article
Recenzirano
NMR self-diffusion, tensiometry, and measurement of solubilization capacity are employed to comparatively study micellization in aqueous solutions of a facial amphiphilic compound, sodium ...deoxycholate (NaDC), and a conventional micelle-forming sodium dodecyl sulfate. Based on the two-state model, which is commonly used to analyze the data of NMR diffusometry, a method is proposed for determining variable sizes of NaDC micelles. It is shown that, in the concentration range from the critical micelle concentration to 0.1 M, the sizes of NaDC micelles monotonically increase. At comparable sizes of molecules of the examined surfactants, NaDC micelles are characterized by noticeably smaller aggregation numbers and solubilization capacity than sodium dodecyl sulfate due to the rigid structure of NaDC molecules, their facial amphiphilicity, and a low value of hydrophilic-lipophilic balance.
The influence of
p
-
tert
-butyl thiacalix4arenes (
1,3-alternate
) functionalized by
N
-propyl morpholine,
N
,
N
-dipropyliden-amine and aminodiacetate fragments on dynamic structure of liposomal ...membranes prepared from dipalmitoyl phosphatidylcholine was investigated by means of electron spin resonance spin-probe technique and Fourier transform infrared spectroscopy. Nuclear magnetic resonance and transmission electron microscopy techniques were applied to characterize the interacting systems. The obtained results have shown that all studied calixarenes interact with polar domains of bilayer. Depending on functional groups and hydrophobic/hydrophilic properties of calixarenes they can dip into bilayer, locate close to the surface of bilayer or form bridges between positively charged groups of adjacent lipid molecules, thus assisting to disordering or putting in order the lipid molecules.
The results of cluster data analysis are discussed with a view to revealing the structure of hormonal regulation of the activity of carbohydrate-lipid metabolism enzymes in white adipose tissue under ...stress conditions. The results, represented as a dendrogram, reflect the hierarchical structure of hormonal regulation of enzymes and stress adaptation syndrome (SAS) and are interpreted according to the logic of biochemical data. The problem is focused on the methodical aspects of the analysis of asymmetric relations on a set of objects with incomplete data.
Two variants of layer-by-layer deposition of polyelectrolytes (polyacrylic acid and polyethyleneimine) for the encapsulation of low-molecular-weight hydrophobic substrates (carboxylic acid esters) ...were proposed. The spectrophotometric method was used to study the kinetics of alkaline hydrolysis of the esters by monitoring the permeability of microcapsule shells. The first procedure provides a preliminary microencapsulation of substrates into the carbonate matrix to form stable capsules 7–10 μm in size with a low wall permeability. According to the second procedure, the polyelectrolytes were adsorbed directly on the dispersed substrate. In this case, nanosized capsules are formed, whose permeability is controlled by the ultrasonic treatment and the number of deposited layers.
The effective self-diffusion coefficients of ions in premicellar and micellar solutions of sodium dodecyl sulfate are measured by the NMR self-diffusion method at 40°C. The obtained regularities are ...explained using a proposed model that takes into account the possible surface diffusion of counterions bound with micelles. This effect is shown to markedly influence the charge transfer in micellar solutions. Based on the results obtained, the self-diffusion coefficients of bound Na
+
counterions are estimated and the causes and ranges of their variations are indicated.
•Both inorganic water and organic ester support nanofibrillated cellulose jelling.•Ester provides transfer of cellulose nanofibrilles to more finely dispersed state.•Free porous medium decreases ...during the transfer from hydrogel to organogel.
The morphology of nanofibrillated cellulose (cellulose nanofibrils or CNF) systems were probed with inorganic water and organic ester as the tracers to determine the porous structure of CNF skeleton. The main novelty of the work was the determined dramatical changes in the gel microscaled porous morphology under replacement of inorganic water by organic ester in the CNF samples of the same origin. For this aim a well-known and well-tested pulsed-field-gradient (PFG) NMR strategy for analyzing mesh size in different porous media was used. For the data analysis the phenomenological scaling approach was applied. It was shown, that the average size of free porous medium dramatically decreases during the transfer of celllose nanofibrils from the inorganic water phase (43 μm) to the organic ester one (1–2 μm). Cooperative analysis of NMR and SEM data for the water and ester CNF-based gels has shown the essential difference in nanoscaled organization of cellulose supramolecular structure. The replacement of water by ester provides the transfer of nanofibrilles to more dispersed state at the nanoscale, which is also confirmed by FTIR experiments.
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Despite the obvious advantages (simplicity of synthesis and for mulation, low concentration, availability, and high complexing ability), a significant drawback of synthetic agents based on cationic ...surfactants is the low transfection efficiency. In view of this, the search for new cationic vector systems is a relevant problem. In this study, we investigated alkylammonium gemline surfactants (AGSs) with the formula R1 CH3 BrH20001 BrH20001 R N (CH2)m N R where m = 412, R = 3, 24, R1 = n Cn2n+ 1, where n = 10, 12, 14, and 16. The synthesized gemline surfactants with the alkylammonium head group may make a good alter native to the existing compounds to deliver genetic material into cells. The optimal conditions for transfection were established.
The purpose of this study was to find arguments in favor of each of the mechanisms of lipase interfacial activation. A number of bile salts differing in hydrohilic and lipophilic properties were ...tested as a factor that regulates the level of lipolytic activity.
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