We have considered procedure and results of the experimental study for spectral characteristics of self emission from laboratory models of electric thrusters with closed electron drift, with special ...reference to a thruster with an anode layer (TAL) and stationary plasma thruster (SPT), for a discharge power of 600, 800, and 1000 W, vertical and horizontal polarizations, and various propellants (krypton, xenon). The study allowed us to reveal a number of specific features of radio-frequency emission from thrusters with closed electron drift in the spectral domain. In particular, it was determined that the TAL has a broadband spectrum recorded in the frequency band from 1 to 4 GHz. Vertical polarization dominated in the studied modes, and the level of radio-frequency emission from TAL operating with krypton was 5–10 dB higher than in the case of its operation with xenon. In turn, the SPT has a broadband spectrum recorded in the frequency band from 1 to 3 GHz. Horizontal polarization slightly dominated in the studied modes. For the SPT, the maximum emission level excess in krypton operation compared to xenon was about 10 dB in the frequency range from 1 to 2 GHz for horizontal polarization. The results allow us to solve the problem of quantitative assessment for the effect of emission from thrusters with closed electron drift on the noise immunity of space communication systems.
Abstract
This paper considers the study of self electromagnetic emission from the experimental model of low-power thruster with anode layer (TAL) developed by the Bauman Moscow State Technical ...University. The measurements were carried out during the thruster operation on krypton and xenon for three operating modes: 600 W, 800 W and 1000 W at a discharge voltage of 300 V. Parameters of the generated electromagnetic fields were measured in frequency range from 1 GHz to 12 GHz in the filter bandwidth of 1 MHz. The receiving antenna was installed at a distance of 1 m from the thruster exit plane, perpendicularly to its axis. The results of analysis and comparison of TAL emission spectral characteristics during its operation on krypton and xenon are presented.
Cytochrome c: the Achilles’ heel in apoptosis Kulikov, A. V.; Shilov, E. S.; Mufazalov, I. A. ...
Cellular and molecular life sciences : CMLS,
06/2012, Letnik:
69, Številka:
11
Journal Article
Recenzirano
Cytochrome
c
is a well-known mitochondrial protein that fulfills life-supporting functions by transferring electrons to the respiratory chain to maintain ATP production. However, during the ...activation of apoptotic machinery, it is released from mitochondria and, being in the cytosol, it either triggers the activation of the caspase cascade in intrinsic apoptotic pathway, or it is involved in the amplification of extrinsic apoptotic signaling. Accumulating evidence suggests that only unmodified holocytochrome
c
is efficient in the stimulation of apoptosis. Considering the importance of cytochrome
c
in both life and death, it was of significant interest to investigate the complete or partial cytochrome
c
deficiency in vivo. Here, we discuss the importance of distinct amino acid residues for various functions of cytochrome
c
in cells and mice with targeted cytochrome
c
mutations.
The genomes of certain types of human and primate herpesviruses contain functional homologs of important host cytokines (IL-6, IL-17, and IL-10), or so-called virokines. Virokines can interact with ...immune cell receptors, transmit a signal to them, and thus switch the type of immune response that facilitates viral infection development. In this work, we have summarized possible ways of virokine origin and proposed an evolutionary scenario of virokine acquisition with involvement of retroviral coinfection of the host. This scenario is probably valid for vIL-6 of HHV-8 and MRV-5 viruses, vIL-17 of HVS virus, and vIL-10 of HHV-4, Bonobo-HV, RhLCV, and BaLCV viruses. The ability to acquire cytokine genes allows herpesviruses to implement unique strategies of avoiding the immune response and provides them an evolutionary advantage: more than 90% of the host population can be chronically infected with different herpesviruses. It is possible that the biological success of herpesviruses can be partially due to their cooperation with another group of viruses. This hypothesis emphasizes the importance of studies on the reciprocal influence of pathogens on their coinfection, as well as their impact on the host organism.
Aim To evaluate the predictive significance of gene polymorphism in endothelin-1 type 2A receptor, NADPH oxidase, p53 protein, endothelial nitric oxide synthase, caspase 8, interleukin-1β, tumor ...necrosis factor-α, superoxide dismutase-2, glutathione peroxidase-1, β1-adrenoceptor, angiotensin-converting enzyme, and matrix metalloproteinase-3 (MMP-3) genes in evaluating the risk of anthracycline-induced cardiotoxicity (AIC) in women without concurrent cardiovascular diseases (CVD).Material and methods This study included 176 women aged 45.0 42.0; 50.0 years with breast cancer without concurrent CVD who were scheduled for polychemotherapy (PCT) with anthracycline antibiotics. Echocardiography was performed for all patients at baseline and at 12 months after the end of PCT course. Genetic polymorphism was determined with the polymerase chain reaction.Results At 12 months, all patients were in remission of the underlying disease. They were retrospectively included into 2 groups: 1st group, 52 patients with AIC and 2nd group, 124 women without AIC symptoms. The development of AIC was associated with the presence of the p53 protein gene Arg / Arg genotype (odds ratio (OR), 2.972; p=0.001), NOS3 gene T / T genotype (OR, 3.059; p=0.018), NADPH oxidase gene T / T genotype (OR, 2.753; p=0.008), GPX1 gene C / C genotype (OR, 2.345; p=0.007), MMP-3 gene 5A / 5A genotype (OR, 2.753; p=0.008), and ADRB1 gene G / G genotype (OR, 3.271; p=0.043).Conclusion Evaluation of genetic polymorphism in p53 protein (rs1042522), NOS3 (rs1799983), NADPH-oxidase (rs4673), GPX1 (rs1050450), ADRB1 (Arg389Gly, rs1801253), and MMP-3 (rs3025058) genes can be recommended for use prior to starting chemotherapy in women with breast cancer without CVD for assessing the risk of AIC. A maximum risk of cardiotoxicity is associated with the presence of the p53 protein gene Arg / Arg genotype and NOS3 gene T / T genotype.
Aim
To study the role of soluble ST2 (sST2), N-terminal pro-brain natriuretic peptide (NT-proBNP), and С-reactive protein (CRP) in patients with chronic heart failure and preserved left ...ventricular ejection fraction (CHF with pLVEF) and syndrome of obstructive sleep apnea (SOSA) in stratification of the risk for development of cardiovascular complications (CVC) during one month of a prospective observation.
Material and methods
The study included 71 men with SOSA with an apnea/hypopnea index (AHI) >15 per hour, abdominal obesity, and arterial hypertension. Polysomnographic study and echocardiography according to a standard protocol with additional evaluation of left ventricular myocardial fractional changes and work index were performed for all patients at baseline and after 12 months of observation. Serum concentrations of sST2 , NT-proBNP, and CRP were measured at baseline by enzyme-linked immunoassay (ELISA).
Results
The ROC analysis showed that the cutoff point characterizing the development of CVC were sST2 concentrations ≥29.67 ng/l (area under the curve, AUC, 0.773, sensitivity 65.71 %, specificity 86.11 %; p<0.0001) while concentrations of NT-proBNP (AUC 0.619; p=0.081) and CRP (AUC 0.511; р=0.869) were not prognostic markers for the risk of CVC. According to data of the ROC analysis, all patients were divided into 2 groups based on the sST2 cutoff point: group 1 included 29 patients with ST2 ≥29.67 ng/l and group 2 included 42 patients with ST2 <29.67 ng/l. The Kaplan-Meyer analysis showed that the incidence of CVC was higher in group 1 than in group 2 (79.3 and 28.6 %, respectively, p<0.001). The regression analysis showed that adding values of AHI and left ventricular myocardial mass index (LVMMI) to sST2 in the model increased the analysis predictive significance.
Conclusion
Measuring sST2 concentration may be used as a noninvasive marker for assessment of the risk of CVC development in patients with CHF with pLVEF and SOSA within 12 months of observation. Adding AHI and LVMMI values to the model increases the predictive significance of the analysis.
The IL-6 family of cytokines includes a variety of proteins that function not only within the immune system, but also in other organs, tissues, and types of cells, including neurons. The common ...evolutionary origin of the IL-6 family proteins determines similar mechanisms of reception and intracellular signaling, although their primary structures are highly variable, as well as their biological functions. We have demonstrated that the members of the IL-6 family have high evolutionary plasticity. This manifests in a high degree of population polymorphism for IL-6 family genes, as well as varying degrees of evolutionary conservation among members of the family. The degree of evolutionary conservation of IL-6 family proteins does not correlate with the mechanisms of interaction between these cytokines and their receptors.
The article demonstrates the relationship between temperamental features and functional state of central nervous system in female students various regimen of reproductive system functioning. The ...sampling included 115 female students of Krasnoyarsk with different status of menstrual function, including 51 female students with normal gonadotropic and prolactin type of anovulation and 64 female students with ovulatory menstrual cycle. The questionnaire DOTS-R was applied to establish the temperament characteristics. The functional condition of the central nervous system was studied using method of simple and complex visual-motor reaction by means of device "Psychophysiologist". The results of the study demonstrated that girls with "calm" and "rigid" types of temperament have features of functional state of the central nervous system that can condition predisposition to menstrual cycle disorders. The particular features of functional state of the central nervous system in female students with anovulatory cycle were established: decreasing of level of activation of the central nervous system in individuals with "intense" and "unstable" types of temperament and workability of girls of "adequate" type. The application of complex reproductive health evaluation to female students to establish personalty temperamental features will input into forming of risk groups relating to development of menstrual cycle disorders in female students.
Aim. To study the effectiveness of oral alendronate and ibandronate bisphosphonates for the prevention of cardiovascular complications in postmenopausal women with type 2 diabetes mellitus (DM) and ...osteoporosis during a 12-month prospective observation. Materials and methods. The study included 86 women with osteoporosis, chronic heart failure (CHF) and type 2 diabetes: the 1st group (n=52) included patients who received basic therapy for heart failure; the 2nd group (n=34) included patients who, in addition to the basic therapy of heart failure, were prescribed alendronic and ibandronic acid preparations for the treatment of osteoporosis. In order to identify the possibility of associating the studied factors with the nature of the course of heart failure, the patients were divided according to the results of a one - year follow - up into two subgroups: subgroup A (n=49) - patients with a favorable course of the disease and subgroup B (n=37) - patients with an unfavorable course of pathology. Results and discussion. After 12 months, a significant decrease in the levels of cerebral natriuretic peptide precursor (NT-proBNP), tumor necrosis factor-α, and interleukin-1β was found in the group of women treated with bisphosphonates compared to baseline. Significant associations of NT-proBNP levels (p=0.02) and the studied cytokines (p=0.01) with an unfavorable course of heart failure were revealed. A significant association of bisphosphonate therapy with a favorable course of heart failure (p=0.01) was also revealed. The probability of developing adverse cardiovascular events during the year in the treatment of heart failure with basic therapy drugs with additional therapy of osteoporosis with bisphosphonates is significantly (p=0.0025) lower than the treatment of patients with heart failure with only basic therapy and not taking bisphosphonates for the treatment of osteoporosis. Conclusion. In postmenopausal women with associated cardiovascular pathology (CHF, type 2 diabetes and osteoporosis), prophylactic therapy with oral alendronate and ibandronate oral bisphosphonates is effective, reduces the risk of progression of heart failure, inhibits inflammatory mediators, positively affects the combined endpoints of comorbid cardiovascular pathology.
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