DNA nanotechnology has significantly advanced and might be used in biomedical applications, drug delivery, and cancer treatment during the past few decades. DNA nanomaterials are widely used in ...biomedical research involving biosensing, bioimaging, and drug delivery since they are remarkably addressable and biocompatible. Gradually, modified nucleic acids have begun to be employed to construct multifunctional DNA nanostructures with a variety of architectural designs. Aptamers are single-stranded nucleic acids (both DNAs and RNAs) capable of self-pairing to acquire secondary structure and of specifically binding with the target. Diagnosis and tumor therapy are prospective fields in which aptamers can be applied. Many DNA nanomaterials with three-dimensional structures have been studied as drug delivery systems for different anticancer medications or gene therapy agents. Different chemical alterations can be employed to construct a wide range of modified DNA nanostructures. Chemically altered DNA-based nanomaterials are useful for drug delivery because of their improved stability and inclusion of functional groups. In this work, the most common oligonucleotide nanomaterials were reviewed as modern drug delivery systems in tumor cells.
Comparative experimental studies of fuel sprays evolution dynamics in a constant volume chamber were carried out with a view to reduce the uneven distribution of diesel fuel in the combustion chamber ...when the Common Rail injector is inclined. The fuel sprays was captured by a high-speed camera with simultaneous recording of control pulses of camera and injector on an oscilloscope. Two eight-hole diesel injectors were investigated: One injector with identical orifice diameter (nozzle 1) and another injector with four orifices of the same diameter as orifices of nozzle 1 and four orifices of enlarged diameters (nozzle 2). Both injectors were tested at rail pressure from 100 to 165 MPa and injector control pulse width of 1.5 ms. The dynamics of changes in the spray penetration length and spray cone angle were determined. It was found that sprays develop differently in nozzle 1 fuel. The difference in the length of fuel sprays is 10–15 mm. As for nozzle 2, the fuel sprays develop more evenly: The difference in length is no more than 3–5 mm. The difference of the measured fuel spray cone angles for nozzle 1 is 0.5°–1.5°, and for nozzle 2 is 3.0°–4.0°. It is concluded that the differential increase in the diameters of nozzle orifices, the axes of which are maximally deviated from the injector axis, makes it possible to reduce the uneven distribution of fuel in the combustion chamber and improve the combustion process and the diesel performance as a whole.
Abstract
The quality of the fuel supply process is the main criterion for ensuring the required indicators of efficiency and environmental friendliness of a diesel locomotive. The electronic control ...system of the ESUVT.01 type for D50 type diesel (6 CHN 31.8/33) for fuel supply control is produced by JSC Penzadizelmash developed in LLC PPP Dieselavtomatika (Saratov) is presented. Optimizing the phase of the beginning of fuel supply – the advance angle of fuel injection (AAFI) shows the possibility of a significant improvement in fuel efficiency and toxicity of diesel exhaust gases. To assess the effect of the AAFI on the diesel locomotive performance, its experimental studies were carried out. The object of bench tests was a diesel generator set of type 1-PDG4D with the specified diesel and with a traction generator MPT-84/39. During the tests, the dependencies of diesel indicators on the AAFI were obtained. The necessity of optimizing the values of the AAFI in accordance with the engine operating mode is confirmed. Optimized values of the AAFI are obtained in the modes of diesel characteristics. The toxicity indicators of diesel exhaust gases and fuel efficiency with optimized characteristics of the AAFI are determined.
Abstract
The toxicity indicators of exhaust gases of a diesel engine largely depend on the quality of the fuel supply process. The possibility of a significant improvement in the toxicity of the ...exhaust gases of a diesel engine by optimizing the phase of the start of fuel supply - the fuel injection advance angle is shown. To assess the influence of the fuel injection advance angle on the dynamic performance of the engine and the toxicity of exhaust gases, a mathematical model of the engine has been developed. The model contains differential equations for the main elements of the combined engine - its piston part, turbocharger, in take and exhaust pipelines. These equations include polynomial dependences of the main engine parameters on its operating parameters. The object of research was diesel type D-245 (4 ChN 11/12.5) produced by the Minsk Motor Plant. Calculations of the acceleration of the engine with a variable fuel injection advance angle have been carried out. The influence of the law of regulation of the advance angle of fuel injection on the duration of the transient process and emissions of normalized toxic components is determined.
First experimental modeling of decarbonation reactions resulting in the formation of CO2-fluid and Mg, Fe, Ca, and Mn garnets, with composition corresponding to the garnets of carbonated eclogites of ...types I and II (ECI and ECII), was carried out at a wide range of lithospheric mantle pressures and temperatures. Experimental studies were performed on a multi-anvil high-pressure apparatus of a “split sphere” type (BARS), in (Mg, Fe, Ca, Mn)CO3-Al2O3-SiO2 systems (with compositional variations according to those in ECI and ECII), in the pressure interval of 3.0–7.5 GPa and temperatures of 1050–1450 °C (t = 10–60 h). A specially designed high-pressure cell with a hematite buffering container—preventing the diffusion of hydrogen into the platinum capsule—was used, in order to control the fluid composition. Using the mass spectrometry method, it was proven that in all experiments, the fluid composition was pure CO2. The resulting ECI garnet compositions were Prp48Alm35Grs15Sps02–Prp44Alm40Grs14Sps02, and compositions of the ECII garnet were Prp57Alm34Grs08Sps01–Prp68Alm23Grs08Sps01. We established that the composition of the synthesized garnets corresponds strongly to natural garnets of carbonated eclogites of types I and II, as well as to garnets from xenoliths of diamondiferous eclogites from the Robert Victor kimberlite pipe; according to the Raman characteristics, the best match was found with garnets from inclusions in diamonds of eclogitic paragenesis. In this study, we demonstrated that the lower temperature boundary of the stability of natural garnets from carbonated eclogites in the presence of a CO2 fluid is 1000 (±20) °C at depths of ~90 km, 1150–1250 (±20) °C at 190 km, and 1400 (±20) °C at depths of about 225 km. The results make a significant contribution to the reconstruction of the fluid regime and processes of CO2/carbonate-related mantle metasomatism in the lithospheric mantle.
Experimental modeling of ankerite–pyrite interaction was carried out on a multi-anvil high-pressure apparatus of a “split sphere” type (6.3 GPa, 1050–1550 °C, 20–60 h). At T ≤ 1250 °C, the formation ...of pyrrhotite, dolomite, magnesite, and metastable graphite was established. At higher temperatures, the generation of two immiscible melts (carbonate and sulfide ones), as well as graphite crystallization and diamond growth on seeds, occurred. It was established that the decrease in iron concentration in ankerite occurs by extraction of iron by sulfide and leads to the formation of pyrrhotite or sulfide melt, with corresponding ankerite breakdown into dolomite and magnesite. Further redox interaction of Ca,Mg,Fe carbonates with pyrrhotite (or between carbonate and sulfide melts) results in the carbonate reduction to C0 and metastable graphite formation (±diamond growth on seeds). It was established that the ankerite–pyrite interaction, which can occur in a downgoing slab, involves ankerite sulfidation that triggers further graphite-forming redox reactions and can be one of the scenarios of the elemental carbon formation under subduction settings.
Aim. To assess the P2Y12 inhibitors switch in patients ST segment elevation myocardial infarction (STEMI) in real-life’ clinical practice, evaluate the functional activity of thrombocytes and ...thrombocytopoiesis and determine the clinical and prognostic value of P2Y12 inhibitors switch in the framework of dual antiplatelet therapy in patients with STEMI.Material and methods. We conducted local, stratified, prospective study in which were involved 101 patients, hospitalized no later than 12hours after the STEMI manifestation. The antiplatelet therapy (APT), prescribed by the physicians at the pre-hospital and inpatient phases of treatment, was analyzed. Functional activity of thrombocytes, levels of thrombopoietin (THPO), stromal cell-derived factor 1 (SDF1) and thrombopoietic receptor (MPL) were investigated. The minimum observation period was 2 years. Death and repeated hospitalizations due to cardiovascular causes were monitored.Results. P2Y12 inhibitors were switched in 32,7% of patients with STEMI. In the hospital, clopidogrel, which was prescribed at the prehospital phase, was replaced with ticagrelor (early APT escalation) — 22,8%. Patients with early APT escalation by the seventh day had significantly greater inhibition of platelet aggregation activity parameters (slope of the aggregation curve, latent aggregation time and area under the aggregation curve). Activation of the collagen-induced platelet aggregation was detected. With the early escalation of APT, the THPO level was statistically significantly higher, both on the second and on the 7th day measurements: 256,2 (209,0; 396,8) pg/ml vs 137,5 (105,7; 179,1) pg/ml (p=0,000) and 283,4 (228,9; 334,3) pg/ml vs 226,5 (163,2; 287,3) pg/ml (p=0,045), respectively. The frequency of reaching the combined endpoint (death + re-hospitalization) was 7,9% in patients who had a P2Y12 switch, and 28,1% in patients who did not change the P2Y12 blocker.Conclusion. In actual clinical practice, patients with STEMI had the most frequent early APT escalation, which was characterized by a more significant suppression of adenosine diphosphate-induced platelet aggregation and secretion than in patients without P2Y12 inhibitors switch, but with activation of collagen-induced aggregation. An increase in thrombocytogenesis was revealed in early replacement of clopidogrel by ticagrelor. Intrahospital replacement of the P2Y12 inhibitor in patients with STEMI was accompanied by a decrease in the two-year death risk and repeated hospitalizations.
An experimental study aimed at the modeling of dolomite- and ankerite-involving decarbonation reactions, resulting in the CO2 fluid release and crystallization of Ca, Mg, Fe garnets, was carried out ...at a wide range of pressures and temperatures of the upper mantle. Experiments were performed using a multi-anvil high-pressure apparatus of a “split-sphere” type, in CaMg(CO3)2-Al2O3-SiO2 and Ca(Mg,Fe)(CO3)2-Al2O3-SiO2 systems (pressures of 3.0, 6.3 and 7.5 GPa, temperature range of 950–1550 °C, hematite buffered high-pressure cell). It was experimentally shown that decarbonation in the dolomite-bearing system occurred at 1100 ± 20 °C (3.0 GPa), 1320 ± 20 °C (6.3 GPa), and 1450 ± 20 °C (7.5 GPa). As demonstrated by mass spectrometry, the fluid composition was pure CO2. Composition of synthesized garnet was Prp83Grs17, with main Raman spectroscopic modes at 368–369, 559–562, and 912–920 cm−1. Decarbonation reactions in the ankerite-bearing system were realized at 1000 ± 20 °C (3.0 GPa), 1250 ± 20 °C (6.3 GPa), and 1400 ± 20 °C (7.5 GPa). As a result, the garnet of Grs25Alm40Prp35 composition with main Raman peaks at 349–350, 552, and 906–907 cm−1 was crystallized. It has been experimentally shown that, in the Earth’s mantle, dolomite and ankerite enter decarbonation reactions to form Ca, Mg, Fe garnet + CO2 assemblage at temperatures ~175–500 °C lower than CaCO3 does at constant pressures.
Meat cattle breeding should develop in Ukraine as a priority and independent industry to meet beef needs. The meat industry has enormous potential and, as the most promising and attractive, will take ...a dominant place in the structure of the domestic food industry in the coming years. Beef is one of the most essential elements of the human diet. It contains complete proteins and animal fats, biologically active substances, mineral elements, and vitamins. The most important feature of food products is their quality and safety indicators, that is, the absence of substances harmful to the consumer's health and pathogens of infectious and invasive diseases. In this regard, veterinary and sanitary expertise and product safety control are of particular importance, as they are necessary to ensure the health of the population of Ukraine. Improving the quality of meat and meat products is a primary task in modern conditions. The implementation of this task depends not only on agricultural but also on processing enterprises. The article presents materials on the study of critical indicators of the safety and quality of beef. The study was carried out as part of the research work of the Department of Normal and Pathological Morphology, hygiene, and Expertise: “Monitoring the content of toxic substances in drinking water, feed and their impact on the body of cattle and the quality and safety of products”, state registration number – 0120U101318. The material for the research was the slaughter products of domestic animals, such as cattle, which were supplied to enterprises in the city of Zhytomyr. Pre-slaughter inspection and veterinary-sanitary examination of carcasses and their slaughter products of cattle was carried out following the “Rules of pre-slaughter veterinary examination of animals and veterinary-sanitary examination of meat and meat products”. The study aims to determine the safety and quality indicators of beef obtained in the conditions of meat processing enterprises of the Zhytomyr region. To achieve this goal, a comprehensive survey of beef safety and quality indicators was conducted. As a result of the tests, it was established that the pH level of the meat was 5.7–6.1. Carrying out the reaction with a 5 % solution of CuSO4 in the broth showed that the broth was transparent. A positive response to peroxidase was also detected. The safety parameters corresponded to regulatory documents. Careful control of the safety and quality of beef at every stage of production, starting from the rearing of animals and up to the sale of the product, guarantees a high degree of consumer protection.
В статті розкриваються теоретико-методологiчнi основи управління прибутковістю підприємств. Представлено економічну природу прибутку та його роль у забезпеченні підприємницької діяльності. Наведено ...особливості управління прибутком підприємств у сучасних умовах. Окреслено вектори покращення ефективності управління прибутком підприємства.
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