was to identify the most effective serum tumor markers for early diagnosis of hepatocellular carcinoma based on the combination of diagnostic characteristics and correlations.
There were observed 55 ...patients with chronic hepatitis C in the stage of liver cirrhosis with a verified diagnosis of hepatocellular carcinoma. The control group consisted of 55 patients with chronic hepatitis C at the stage of liver cirrhosis without hepatocellular carcinoma, comparable to the experimental group in terms of basic clinical profile. The following tumor markers were estimated in both groups: alpha-fetoprotein (AFP), alpha-fetoprotein-L3 (AFP-L3), annexin A2 (ANXA2), heparin-binding growth factor Midkine (MDK), glypican-3 (GPC3), des-gamma-carboxyprothrombin (DCP, PIVKA-II), dickkopf-related protein 1 (DKK-1), osteopontin (OPN), and Golgi protein 73 (GP73). There were also evaluated such indices as diagnostic sensitivity, specificity, positive predictive value, negative predictive value, likelihood ratio of a positive test, the possible correlation between alpha-fetoprotein and other tumor markers. The area under the ROC curve (AUC) was calculated at the 95% confidence interval.
The greatest sensitivity was revealed when using heparin-binding growth factor, annexin A2, osteopontin. Alpha-fetoprotein, alpha-fetoprotein-L3, glypican-3, des-gamma-carboxyprothrombin, dickkopf-related protein 1 had the best specificity. AUC>0.75 was found in annexin A2, heparin-binding growth factor, glypican-3, des-gamma-carboxyprothrombin, osteopontin, Golgi protein 73. The likelihood ratio of a positive test result was the highest for glypican-3. A significant correlation was found between alpha-fetoprotein and alpha-fetoprotein-L3, annexin A2, des-gamma-carboxyprothrombin.
According to the aggregate indicators of diagnostic efficiency, heparin-binding growth factor, glypican-3, and osteopontin are the most promising tumor markers of those studied. When they are used, integral AUC values are above the average, the level of these tumor markers in the blood of patients with hepatocellular cancer does not correlate with alpha-fetoprotein. They are applicable for diagnosing liver cancer in AFP-negative patients. The combined use of AFP + GPC3, AFP + OPN has already shown their advantages. However, the efficacy of the combination of AFP + MDK, GPC3 + OPN has not been determined yet; therefore, significance of the combined use of these tumor markers in the diagnosis of liver cancer should be investigated in the near future.
The CHAMP magnetic field mission is providing highly reliable measurements from which the global lithospheric magnetic field can be determined in unprecedented resolution and accuracy. Using almost 5 ...yr of data, we derive our fourth generation lithospheric field model termed MF4, which is expanded to spherical harmonic degree and order 90. After subtracting from the full magnetic field observations predicted fields from an internal field model up to degree 15, an external field model up to degree two, and the predicted magnetic field signatures for the eight dominant ocean tidal constituents, we fit and remove remaining external fields and polar electrojet signatures in a track-by-track scheme. From a subset of least disturbed tracks, we estimate the MF4 model by least squares, damping ill-determined coefficients by regularization. The resulting MF4 model provides a good representation of the lithospheric field down to an altitude of about 50 km at lower latitudes, with reduced accuracy in the polar regions. Crustal features come out significantly sharper than in previous models. In particular, bands of magnetic anomalies along subduction zones become visible by satellite for the first time.
It is shown that electrodynamic tests of power transformers are accompanied by the predominant consumption of a reactive power that is many times higher than the active-power consumption. A scheme of ...electrodynamic tests with longitudinal compensation of the reactive power using a capacitor bank is proposed. It allows a considerable reduction of the power that is consumed from the power-supply system. The parameters of the capacitor bank and the preliminary-charging voltage levels were determined that provide various current regimes for conducting both adjusting and actual short-circuiting experiments. The possibility of performing electrodynamic tests of power transformers with nominal powers of up to 630 MV A under the conditions of factory test centers using a controlled alternating-voltage source with a regulation range of 1.5–7.5 kV and a power of 22 MW was substantiated. Short-circuiting tests have a negative effect on the power-supply system because they are able to initiate a voltage dip with a duration of up to 0.2 s and even a dynamic-stability loss. As a result, the quality and reliability of electric-power supply of other consumers of the power-supply system deteriorate. The above negative consequences can be avoided and the required testing short-circuit current simultaneously provided via reduction of the total power consumed from the powersuppl system. In this study, the problem of the electromagnetic compatibility of an electrodynamic-test bench and a power-supply system is solved by compensating the reactive power during short-circuiting experiments.
We present the results of the prompt, early and afterglow optical observations of five γ-ray bursts (GRBs): GRB 100901A, GRB 100902A, GRB 100905A, GRB 100906A and GRB 101020A. These observations were ...made with the Mobile Astronomical System of TElescope-Robots in Russia (MASTER-II Net), the 1.5-m telescope of the Sierra Nevada Observatory and the 2.56-m Nordic Optical Telescope. For two sources, GRB 100901A and GRB 100906A, we detected optical counterparts and obtained light curves starting before the cessation of γ-ray emission, at 113 and 48 s after the trigger, respectively. Observations of GRB 100906A were conducted in two polarizing filters. Observations of the other three bursts gave the upper limits on the optical flux; their properties are briefly discussed. A more detailed analysis of GRB 100901A and GRB 100906A, supplemented by Swift data, provides the following results and indicates different origins for the prompt optical radiation in the two bursts. The light-curve patterns and spectral distributions suggest that there is a common production site for the prompt optical and high-energy emission in GRB 100901A. The results of the spectral fits for GRB 100901A in the range from optical to X-ray favour power-law energy distributions and a consistent value of the optical extinction in the host galaxy. GRB 100906A produced a smoothly peaking optical light curve, suggesting that the prompt optical radiation in this GRB originated in a front shock. This is supported by a spectral analysis. We have found that the Amati and Ghirlanda relations are satisfied for GRB 100906A. We obtain an upper limit on the value of the optical extinction on the host of GRB 100906A.
ESA's satellite magnetometer mission Swarm is supposed to lower the limit of observability for oceanic processes. While periodic magnetic signals from ocean tides are already detectable in satellite ...magnetometer observations, changes in the general ocean circulation are yet too small or irregular for a successful separation. An approach is presented that utilizes the good detectability of tidal magnetic signals to detect changes in the oceanic electric conductivity distribution. Ocean circulation, tides, and the resultant magnetic fields are calculated with a global general ocean circulation model coupled to a 3‐D electromagnetic induction model. For the decay of the meridional overturning circulation, as an example, the impact of climate variability on tidal oceanic magnetic signals is demonstrated. Total overturning decay results in anomalies of up to 0.7 nT in the radial magnetic M2 signal at sea level. The anomalies are spatially heterogeneous and reach in extended areas 30% or more of the unperturbed tidal magnetic signal. The anomalies should be detectable in long time series from magnetometers on land or at the ocean bottom. The anomalies at satellite height (430 km) reach 0.1 nT and pose a challenge for the precision of the Swarm mission. Climate variability induced deviations in the tide system (e.g., tidal velocities and phases) are negligible. Changes in tidal magnetic fields are dominated by changes in seawater salinity and temperature. Therefore, it is concluded that observations of tidal magnetic signals could be used as a tool to detect respective state changes in the ocean.
Key Points:
Climate variability impacts ocean electric conductivity distribution
Climate variability can significantly influence oceanic tidal magnetic signals
Climate induced ocean variability is in principle separable in magnetic observations
To enhance the oil recovery of high-viscosity oil deposits in the temperature range of 20-210 °C, the multifunctional composition based on surfactants, aluminum and ammonium salts, an adduct of ...inorganic acid, carbamide and polyol with an adjustable viscosity and high oil-displacing ability was created. The composition has a low interfacial tension, a high buffer capacity in a wide pH range, 2.5-10 units pH, a delayed reaction with carbonate rocks, prevents the precipitation of insoluble reaction products, increases the permeability of reservoirs. The composition is both oil-displacing and flow-diverting, provides an enhance in the oil recovery factor (ORF) due to the increase in the oil displacement and formation sweep by water or steam flooding. Practical recommendations are given on the application of the composition at the Permian-Carboniferous deposits of the Usinsk oilfield.
At coastal sites, geomagnetic variations for periods shorter than a few days are strongly distorted by the conductivity of the nearby sea-water. This phenomena, known as the ocean (or coast) effect, ...is strongest in the magnetic vertical component. We demonstrate the ability to predict the ocean effect of geomagnetic storms at geomagnetic observatories. The space-time structure of the storm is derived from the horizontal components at worldwide distributed observatories from which we predict the vertical component using a model of the Earth’s conductivity that a) only depends on depth, and b) includes the conductivity of the sea-water. The results for several strong geomagnetic storms (including the “Bastille Day” event of July 14–15, 2000) show much better agreement (improvement by up to a factor of 2.5) between the observed and the modeled magnetic vertical component at coastal sites if the oceans are considered. Our analysis also indicates a significant local time asymmetry (i.e., contributions from spherical harmonics other than P10), especially during the main phase of the storm.
Within the framework of green chemistry principles, the concept of deep eutectic solvents (DES) was used to develop solid commercial forms of oil-displacing compositions. It has been shown that the ...eutectic composition on the phase diagram of the binary system ammonium salt - carbamide corresponds to DES as the basis of solid commercial forms of oil-displacing composition with the best physicochemical and technological characteristics. The optimal concentrations of solid commercial forms in the working solution of the composition were determined for the ternary DES system ammonium salt - carbamide - water. The results of laboratory studies and field tests of the working solution based on the solid commercial forms of the oil-displacing composition are presented.
CONTROL SYSTEM DEPENDING ON A PARAMETER Ushakov, Vladimir N.; Ershov, Aleksandr A.; Ushakov, Andrey V. ...
Ural mathematical journal,
07/2021, Letnik:
7, Številka:
1
Journal Article
Recenzirano
Odprti dostop
A nonlinear control system depending on a parameter is considered in a finite-dimensional Euclidean space and on a finite time interval. The dependence on the parameter of the reachable sets and ...integral funnels of the corresponding differential inclusion system is studied. Under certain conditions on the control system, the degree of this dependence on the parameter is estimated. Problems of targeting integral funnels to a target set in the presence of an obstacle in strict and soft settings are considered. An algorithm for the numerical solution of this problem in the soft setting has been developed. An estimate of the error of the developed algorithm is obtained. An example of solving a specific problem for a control system in a two-dimensional phase space is given.
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