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排序方式: 共有189条查询结果,搜索用时 19 毫秒
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2.
TNF-α gene polymorphisms: association with age-related macular degeneration in Russian population
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Valeriy Chernykh Alla Shevchenko Vladimir Konenkov Viktor Prokofiev Alena Eremin Alexander Trunov 《国际眼科》2019,12(1):25-29
AIM: To study polymorphisms in promotor regions of tumor necrosis factor (TNF)-α TNF-863A/C (rs1800630), TNF-308A/G (rs1800629), and TNF-238A/G (rs361525) in patients with age-related macular degeneration (AMD) and associations of complex TNF-α genotypes with AMD.
METHODS: One hundred and two patients (82 women, 20 men; mean age 64.2±1.2y) with AMD and 100 healthy age- and sex-matched controls (82 women, 18 men; 60±1.4y) were included in the study. All subjects were Caucasian, all subjects and their parents were inhabitants of Russia. Genomic DNA was obtained from EDTA-preserved blood using the standard phenol-chloroform method. Polymorphisms were detected by polymerase chain reaction followed by the restriction fragment length polymorphism method. The following TNF-α genotypes were studied: TNF-α-238 AA, GA, GG, TNF-α-308 AA, GA, GG, TNF-α-863 AA, CA, CC.
RESULTS: Differences in TNF-α-863 and TNF-α-238 genotypes frequencies in patients with AMD and healthy controls were not found. The distribution of TNF-α-308 AA and TNF-α-308 GA genotypes was significantly different between the studied group and the controls [odds ratios (OR) =0.22, P=0.0287 and OR=2.91, P=0.0063, respectively]. TNF-863CC/TNF-308GA and TNF-308GA/TNF-238GG genotypes were associated with the increased risk of AMD (OR=2.48, P=0.0332 and OR=2.51, P=0.0187, respectively). Five genotypes combinations appeared to be protective.
CONCLUSION: In the present study, single nucleotide polymorphisms and complex polymorphisms of one of the key inflammatory cytokines TNF-α, and a number of significant associations of these polymorphisms with AMD in Russian population have been shown. Complex analysis of genotypes could be important in AMD risk factors detection and studying pathogenesis. 相似文献
3.
Leonid Agureev Valeriy Kostikov Svetlana Savushkina Zhanna Eremeeva Maxim Lyakhovetsky 《Materials》2022,15(17)
Materials based on the NiAl-Cr-Mo system with zirconium oxide or aluminum-magnesium spinel nanoparticle small additions were obtained by spark plasma sintering. Thermodynamic modeling was carried out to predict the phase formation in the NiAl-Cr-Mo system and its change depending on temperature, considering the presence of a small amount of carbon in the system. The phase composition and microstructure of materials were studied. NiAl (B2) and CrMo phases were found in the sintered samples. Bending strength measurements at different temperatures shows that nanoparticles of insoluble additives lead to an increase in bending strength, especially at high temperatures. A fractographic analysis of the sample’s fractures shows their hybrid nature and intercrystalline fracture, which is confirmed by the clearly visible matrix grains similar to cleavage. The maximum strength at 700 °C (475 MPa) was found for material with the addition of 0.1 wt.% zirconium oxide nanoparticles. In the study of internal friction, typical peaks of a nickel-aluminum alloy were found in the temperature ranges of 150–200 °C and 350–400 °C. 相似文献
4.
Svetlana Popova Victoria Tazetdinova Erzhena Pavlova Galina Matafonova Valeriy Batoev 《Materials》2022,15(15)
Naturally occurring sono- and photoactive minerals, which are abundant on Earth, represent an attractive alternative to the synthesized sonophotocatalysts as cost-effective materials for water and wastewater treatment. This study focuses on characterizing and evaluating the sonophotocatalytic activity of natural sphalerite (NatS) from Dovatka deposit (Siberia) under high-frequency ultrasonic (US, 1.7 MHz) and ultraviolet light-emitting diodes (UVA LED, 365 nm) irradiation towards degradation of 4-chlorophenol as a model organic pollutant. Since raw natural sphalerite did not exhibit a measurable photocatalytic activity, it was calcined at 500, 900 and 1200 °C. The natural sphalerite after calcination at 900 °C (NatS*) was found to be the most effective for sonophotocatalytic degradation of 4-chlorophenol, attaining the highest efficiency (55%, 1 h exposure) in the following row: UV < US ≈ UV/US ≈ US/NatS* < UV/NatS* < UV/US/NatS*. Addition of 1 mM H2O2 increased the removal to 74% by UV/US/NatS*/H2O2 process. An additive effect between UV/NatS* and US/NatS* processes was observed in the sonophotocatalytic system as well as in the H2O2-assisted system. We assume that the sonophotocatalytic hybrid process, which is based on the simultaneous use of high-frequency ultrasound, UVA light, calcined natural sphalerite and H2O2, could provide a basis of an environmentally safe and cost-effective method of elimination of organic pollutants from aqueous media. 相似文献
5.
Butov Dmytro Feshchenko Yurii Myasoedov Valeriy Kuzhko Mykhailo Gumeniuk Mykola Gumeniuk Galyna Tkachenko Anton Nataliya Nekrasova Borysova Olena Butova Tetiana 《Wiener Medizinische Wochenschrift》2022,172(11-12):261-267
Wiener Medizinische Wochenschrift - This study assessed the effectiveness and diagnostic significance of hypertonic saline sputum induction for improving Mycobacterium tuberculosis (MTB) detection.... 相似文献
6.
Philipp Y Maximov Russell E McDaniel Daphne J Fernandes Valeriy R Korostyshevskiy Puspanjali Bhatta Thomas E Mürdter David A Flockhart V Craig Jordan 《British journal of pharmacology》2014,171(24):5624-5635
Background and Purpose
Tamoxifen is a prodrug that is metabolically activated by 4-hydroxylation to the potent primary metabolite 4-hydroxytamoxifen (4OHT) or via another primary metabolite N-desmethyltamoxifen (NDMTAM) to a biologically active secondary metabolite endoxifen through a cytochrome P450 2D6 variant system (CYP2D6). To elucidate the mechanism of action of tamoxifen and the importance of endoxifen for its effect, we determined the anti-oestrogenic efficacy of tamoxifen and its metabolites, including endoxifen, at concentrations corresponding to serum levels measured in breast cancer patients with various CYP2D6 genotypes (simulating tamoxifen treatment).Experimental Approach
The biological effects of tamoxifen and its metabolites on cell growth and oestrogen-responsive gene modulation were evaluated in a panel of oestrogen receptor-positive breast cancer cell lines. Actual clinical levels of tamoxifen metabolites in breast cancer patients were used in vitro along with actual levels of oestrogens observed in premenopausal patients taking tamoxifen.Key Results
Tamoxifen and its primary metabolites (4OHT and NDMTAM) only partially inhibited the stimulant effects of oestrogen on cells. The addition of endoxifen at concentrations corresponding to different CYP2D6 genotypes was found to enhance the anti-oestrogenic effect of tamoxifen and its metabolites with an efficacy that correlated with the concentration of endoxifen; at concentrations corresponding to the extensive metabolizer genotype it further inhibited the actions of oestrogen. In contrast, lower concentrations of endoxifen (intermediate and poor metabolizers) had little or no anti-oestrogenic effects.Conclusions and Implications
Endoxifen may be a clinically relevant metabolite in premenopausal patients as it provides additional anti-oestrogenic actions during tamoxifen treatment. 相似文献7.
ukasz Poloczek ukasz Rauch Marek Wilkus Daniel Bachniak Wadysaw Zalecki Valeriy Pidvysotskyy Roman Kuziak Maciej Pietrzyk 《Materials》2021,14(1)
The paper describes physical and numerical simulations of a manufacturing process composed of hot forging and controlled cooling, which replace the conventional heat treatment technology. The objective was to investigate possibilities and limitations of the heat treatment with the use of the heat of forging. Three steels used to manufacture automotive parts were investigated. Experiments were composed of two sets of tests. The first were isothermal (TTT) and constant cooling rate (CCT) dilatometric tests, which supplied data for the identification of the numerical phase transformation model. The second was a physical simulation of the sequence forging-cooling on Gleeble 3800, which supplied data for the validation of the models. In the numerical part, a finite element (FE) thermal-mechanical code was combined with metallurgical models describing recrystallization and grain growth during forging and phase transformations during cooling. The FE model predicted distributions of the temperature and the austenite grain size in the forging, which were input data for further simulations of phase transformations during cooling. A modified JMAK equation was used to calculate the kinetics of transformation and volume fraction of microstructural constituents after cooling. Since the dilatometric tests were performed for various austenitization temperatures before cooling, it was possible to include austenite grain size as a variable in the model. An inverse algorithm developed by the authors was applied in the identification procedure. The model with optimal material parameters was used for simulations of hot forging and controlled cooling in one of the forging shops in Poland. Distributions of microstructural constituents in the forging after cooling were calculated. As a consequence, various cooling sequences during heat treatment could be analyzed and compared. 相似文献
8.
Kumar U Chen J Sapoznikhov V Canteros G White BH Sidhu A 《Clinical and experimental hypertension (New York, N.Y. : 1993)》2005,27(1):17-31
In kidney, nitric oxide (NO) produced by nitric oxide synthase (NOS) regulates sodium and water excretion and renal medullary blood flow. However, excessive NO production causes nitrative damage and oxidative stress. Since oxidative stress may be linked to hypertension, we examined the expression and activity of inducible NOS (iNOS) in the kidney of the spontaneously hypertensive rat (SHR) and compared our findings to control normtotensive Wistar Kyoto (WKY) rat. Compared with WKY rat, there was significant (p < .05) overexpression (by 96%) and increased (2-fold) activity of iNOS in the cortex but not in the outer medulla, of SHR kidney; in the inner medulla, there was a 6.9-fold increase in iNOS activity in SHR. Increased expression (by 104%) and activity (3.3-fold) of iNOS was specifically observed in proximal tubules (PTs) of the cortex, accompanied by higher (2-fold) tissue nitrite levels. Although certain antioxidant enzymes such as catalase and Mn-superoxide dismutase were overexpressed, glutathione peroxidase was underexpressed in SHR PTs. Overexpression of the inducer of the iNOS promoter, nuclear factor-kappaB (NF-kappaB), with elevated nitrotyrosinylated proteins, further confirmed an elevated state of iNOS-induced oxidative stress in SHR kidneys, possibly signifying its role in the maintenance of essential hypertension seen in these animals. 相似文献
9.
Ildar Salakhov Elena Tkacheva Valeriy Kozlov Dmitriy Galanin Anas Sakhabutdinov 《RSC advances》2021,11(34):20916
The regularities of ethylene–propylene copolymerisation over a vanadium oxytrichloride (VOCl3)–ethylaluminium sesquichloride (EASC) catalytic system in the presence of hexachloro-p-xylene (HCPX), tert-butyl chloride, trichlorotoluene, hexachlorocyclopentadiene, and trichloroacetate were studied. The main kinetic regularities of ethylene–propylene copolymerisation when using HCPX were determined and the kinetic parameters of the process were obtained. It was shown that hexachloro-p-xylene is the most efficient promoter of polymerisation that increases activity of the “vanadium” catalyst severalfold and enhances propylene reactivity in its copolymerisation with ethylene. A number of molecular characteristics and physicochemical parameters were determined for the synthesised samples of ethylene–propylene copolymers. The resulting copolymers have a higher molecular weight and a broad molecular weight distribution and are richer in propylene monomers compared to the copolymers synthesised in the catalytic system without HCPX. Modification of the “vanadium” catalyst yields the copolymer with a more homogeneous structure. Assumptions were made about the mechanism of action of the promoter under study in the VOCl3–EASC catalytic system.Hexachloro-p-xylene was found to be an effective promoter of olefin copolymerisation in the presence of vanadium catalyst, which increases the activity severalfold, enhances propylene incorporation in the copolymer, and results in a more homogeneous polymer. 相似文献
10.
Sveta Zhiraslanovna Ozkan Galina Petrovna Karpacheva Mikhail Nikolaevich Efimov Andrey Aleksandrovich Vasilev Dmitriy Gennad'evich Muratov Valeriy Alekseevich Petrov Petr Aleksandrovich Chernavskii Galina Viktorovna Pankina 《RSC advances》2021,11(40):24772
A one-step preparation method for hybrid electromagnetic nanomaterials based on polydiphenylamine (PDPA) and bimetallic Co–Fe particles in the absence and presence of single-walled carbon nanotubes (SWCNT) was proposed. During IR heating of PDPA in the presence of Co(ii) and Fe(iii) salts in an inert atmosphere at T = 450–600 °C, the polycondensation of diphenylamine (DPA) oligomers and dehydrogenation of phenyleneamine units of the polymer with the formation of C N bonds and reduction of metals by evolved hydrogen with the formation of bimetallic Co–Fe particles dispersed in a polymer matrix occur simultaneously. When carbon nanotubes are introduced into the reaction system, a nanocomposite material is formed, in which bimetallic Co–Fe particles immobilized on SWCNT are distributed in the matrix of the polymer. According to XRD data, reflection peaks of bimetallic Co–Fe particles at diffraction scattering angles 2θ = 69.04° and 106.5° correspond to a solid solution based on the fcc-Co crystal lattice. According to SEM and TEM data, a mixture of particles with sizes of 8–30 nm and 400–800 nm (Co–Fe/PDPA) and 23–50 nm and 400–1100 nm (Co–Fe/SWCNT/PDPA) is formed in the nanocomposites. The obtained multifunctional Co–Fe/PDPA and Co–Fe/SWCNT/PDPA nanomaterials demonstrate good thermal, electrical and magnetic properties. The saturation magnetization of the nanomaterials is MS = 14.99–31.32 emu g−1 (Co–Fe/PDPA) and MS = 29.48–48.84 emu g−1 (Co–Fe/SWCNT/PDPA). The electrical conductivity of the nanomaterials reaches 3.5 × 10−3 S cm−1 (Co–Fe/PDPA) and 1.3 S cm−1 (Co–Fe/SWCNT/PDPA). In an inert medium, at 1000 °C the residue is 71–77%.In a self-organizing system within one stage under IR heating conditions, hybrid nanomaterials are formed with a structure that contains bimetallic Co–Fe particles, free or immobilized on the SWCNT surface, dispersed in the polymer PDPA matrix. 相似文献