A comparative study of the relative antioxidant activity (RAA) of fullerene С
60
and its amino acid derivatives is performed via amperometry and fluorimetry. The sizes of nanoparticles in the ...corresponding colloidal solutions are determined via dynamic light scattering (photon correlation spectroscopy) to study the effect the steric factors of the investigated compounds have on the magnitude of the RAA. Data are subjected to statistical correlation regression analysis using results obtained for the RAA dependence of fullerene С
60
and salt forms of its acid derivatives on the corresponding sizes of nanoparticles in colloidal aqueous solutions. A close negative (inverse) correlation is identified between the size of nanoparticles in a solution and their antioxidant properties, with a pronounced synergic effect related to the influence of both chemical structure of the studied compounds and their structural organization in colloid solution. It is found that the structure of a substituent in a molecule of amino acid derivative of fullerene С
60
also influences the size of the forming nanoparticles. At the same time, reductive properties of amino acid derivatives of fullerene С
60
are generally determined by the electron effects of substituents.
The current scientific article examines preventive anti-crisis management. In a modern economy, a company must anticipate possible crisis situations and do everything possible to prevent them, ...therefore this type of crisis management is very important. The article examines the various approaches of the research authors to the definition of preventive anti-crisis management, highlights its features and main tasks, and lists the tools that are used in this kind of management.
Background
. The incidence of colon cancer over the past decade has been growing markedly in the Russian Federation, with about 50 % cases detected at stagesIII–IV of the disease, when a clear ...clinical picture of the disease appears. In this regard, the search for new methods for early diagnosis of RTK is undoubtedly relevant.
Objective
. To determine the standard composition of the aerobic parietal colon microbiota and the level of cytokines (chemokines and growth factors) in patients with cancer of the left half of the colon and to assess the possibility of using these data in the diagnosis of the tumor process.
Materials and methods
. Blood tests were performed on the day of the study using two test systems (BioLegend): multiplex kit for determining growth factors, chemokine multiplex kit. The composition of the intestinal microbiota was determined in colon biopsy specimens by the bacteriological method using the standard test systems StaphyTest, StreptoTest, and EnteroTest.
Results
. There is an increase in the number of Clostridiumspp. and a decrease in Bifidobacteriumspp., E. coli in the colon during the transformation of a healthy person’s mucosa into a malignant tumor (p < 0.05); a clear tendency was revealed for both an increase (EGF, HGF, M-CSF, PDGF-AA, PDGF-BB, IP-10) and a decrease (MCP-1, RANTES) of the level of chemokines and growth factors under colon cancer conditions. In addition to general quantitative changes in the intestinal microbiota, the level of the investigated substances, a statistically significant dependence was established on the sex, age of the patient, as well as the degree of differentiation and form of tumor growth.
Conclusion
. It was established that changes in the quantitative composition of the intestinal microbiota, the level of some biologically active substances that occur precisely in the conditions of colon cancer, can be interconnected and interdependent, and also serve as an additional diagnostic marker in the detection of a malignant tumor.
The positron-hydrogen atom and the positron-positive helium ion scattering problems at the energies below the second excitation threshold of the positronium are solved by the potential splitting ...approach combined with the complex scaling technique. We solve the Schrödinger equation in the total angular momentum representation. The elastic scattering and excitation cross-sections are obtained.
The proposed approach allows us to evaluate the response of forest stands to local weather changes and resistance to insect attack without using data from weather stations, sometimes located far from ...experimental forest areas. All raw data were obtained during the season using remote sensing data (MODIS / AQUA). The ability to pre-determine decrease and loss of forest stands resistance to possible insect attacks can be extremely important for solving the tasks of forest-entomological monitoring and calculating the risk of forest insect's outbreaks.
A dynamic clustering algorithm for temperature signals is considered. It is used for solving the problem of distinguishing climatic regions characterized by a certain homogeneous climate type within ...the boundaries of the region on the Earth’s surface. A numerical experiment implemented with the aim of estimating its stability is described. The reference signal model used in the numerical experiment is presented as a sum of harmonic components. Additive components of the noise are formed in the frequency region. In the numerical experiment, the noise magnitude and sample size are measured. Estimates of root-mean-square deviations and stability of the dynamic clustering algorithm are presented.
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•PIM-1 material was used for solute fractionation by means of solvent swing adsorption (SSA).•Solvents used in SSA can be regenerated by PIM-1 membranes.•PIM-1 can be turned from ...solvent-selective into solute-selective membrane by changing the solvent nature.
A concept is demonstrated for the separation of two organic solutes from a common solvent by solvent swing adsorption (SSA), coupled with organic solvent nanofiltration (OSN) for solvent recycling. The polymer of intrinsic microporosity PIM-1 was utilized both for the adsorbent and for the nanofiltration membrane. For adsorption from solution in ethanol or water–ethanol (30/70) mixture, PIM-1 showed high affinity for a neutral solute (Oil Red O) with negligible uptake of an anionic solute (Remazol Brilliant Blue R). The obtained equilibrium values of distribution coefficient K revealed that Oil Red O can be concentrated in PIM-1 by 4300 times from its ethanol solution, and this value can be significantly improved up to 53,000 times in the case of water/ethanol (30/70) binary mixture. Such difference in the affinity of neutral solute to PIM-1 was explained by means of competitive sorption between solute and solvent molecules, and a clear relationship between distribution coefficient K and solvent solubility parameter was observed. The adsorbent could be regenerated by washing with a less polar solvent (toluene), which gave almost quantitative desorption of the neutral solute (K=6). PIM-1 membranes as cast and after cross-linking were also successfully utilized for solvent recovery. It was demonstrated that PIM-1 membranes can possess either solvent-selective transport or solute-selective transport in OSN, depending on the nature of the solvent.
Previously undescribed norbornene monomer 3,3,4-trifluoro-4-perfluorohexyltricyclononene-7 is synthesized by the 2+2+2 cycloaddition reaction. The monomer is involved in the ring-opening ...polymerization metathesis in the presence of the first-generation Grubbs catalyst to give rise to the amorphous, glassy unsaturated polymer. The gas-transport properties of the metathesis polymer is studied, the gas permeability and diffusion coefficients for a wide range of gases (He, H
2
, O
2
, N
2
, CO
2
, CH
4
) are determined, and the solubility coefficients of gases in this polymer are calculated.
In this article, consideration is given to a mathematical model and a numerical method to calculate and optimize the process of high-speed thawing of grounds using microwave energy. Relevant examples ...of calculations and an analysis of results are presented.
Let K be a multidimensional local field with characteristic different from the characteristic of its residue field, c be a unit of K, and F
c
(X, Y) = X +Y +cXY be a polynomial formal group, which ...defines the formal module F
c
(
M
) over the maximal ideal of the ring of integers in K. Assume that K contains the group of roots of the isogeny
p
m
c
(X), which we denote by μ
F
c
,
m
. Let
be the multiplicative group of Cartier curves and
c
be the formal analog of the module Fc(
M
). In the present paper, the formal symbol { ·, · }c : K
n
(
)×
c
→ μ
F
c
,
m
is constructed and its basic properties are checked. This is the first step in the construction of an explicit formula for the Hilbert symbol.
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