Diagnostic value of ultrasound in the evaluation of the echostructures of the nodular formation of the thyroid gland using the classification system TI-RADS

Objective. Estimation of the ultrasonographic criteria efficacy in accordance to the TI-RADS system while determining the morphological structures of nodal thyroid affections. Materials and methods. Results of ultrasonographic investigation in 546 patients, ageing 17 - 76 old and suffering thyroidal nodal affections, were analyzed. All the patients were divided into two groups. Into the firsr group  (the main) 427 (78.2%) patients were included, to whom ultrasonographic investigation was performed by a surgeon-endocrinologist. Into the second group (the control one) 119 (21.8%) patients were included, to whom ultrasonographic investigation was performed by a radiologist. Ultrasonographic criteria with nodal thyroidal affections were estimated in accordance to the TI-RADS scale, and the results of cytological investigations of the nodal affections - in accordance to criteria of the Bethesda system. The degree of the malignant nodal affections risk was determined, taking into account a quantity of intranodal echographic signs in accordance to the points gradation, using a Ti-RADS system. Results. In accordance to results of pathohistological investigations of the removed specimen a benign changes were revealed in 128 (76.6%) patients, and malignant - in 39 (23.4%). In structure of malignant affections papillary cancer was established in 23 patients, follicular - in 13, medullary - in 2, Hurtle-cellular - in 1 patient. In accordance to cytological investigations, conducted in 2014 - 2018 yrs., there was established, that in the first group a fine-needle biopsy was conducted in 211/427(49.4%) patients. Operative interventions were performed in 105 (24.6%) patients. In the second group a fine-needle biopsy was performed in 64/119 (53.8%) patients. Operative intervention was conducted in 62 (52.1%) patients. Conclusion. While conduction of ultrasonographic investigation by a surgeon-endocrinologist the rate of revealing of false-positive echographic signs have lowered in more than 2 times (1.4%), comparing with analogous index while conduction of the investigation by radiologist (3.1%). Application of a TI-RADS classification have permitted to reduce the rate of the fine-needle biopsy and doing of surgical interventions

Structure and electrophysical properties of polyvinylidene fluoride (PVDF)/magnetite nanocomposites

In the present study, the effect of magnetite (Fe3O4) nanoparticles on the structural and dielectric properties of poly(vinylidene fluoride) (PVDF) matrix was investigated. Distribution of Fe3O4 nanoparticles in the polymer matrix has been studied by scanning electron microscopy (JEOL JSM-7600 F). The structure of the nanocomposite samples was investigated by the X-ray diffraction and Fourier-transform infrared spectroscopy. It was shown that the dielectric permittivity of PVDF + Fe3O4 nanocomposite samples was gradually increased up to 7 wt% of Fe3O4 content. Further increase in the concentration of the filler leads to decrease in the dielectric permittivity. The subsequent decrease in dielectric permittivity at higher Fe3O4 content can be explained by the increase in defects in the structure of the nanocomposite. The comparison of experimental data and the results of theoretical calculations show that the reduction in the empirical value of dielectric permittivity of the nanocomposite is obviously linked with the threshold value of filler. While calculating the theoretical value of the dielectric permittivity for the higher content of the filler, defects in the nanocomposite structure should be considered

Influence of Polarization Processes on the Morphology and Photoluminescence Properties of PP/TiO₂ Polymer Nanocomposites

The paper reports of synthesis and investigation of polymeric nanocomposites based on isotactic polypropylene and titanium dioxide nanoparticles PP+TiO₂ (PPT). The structure of the PPT nanocomposites was studied by scanning electron and atomic force microscopy. There was also studied the influence of the polarization process by corona discharge on the structure and photoluminescence properties of PPT nanocomposites. It was found that intensity of the photoluminescence after the polarization increases, and this depends on the concentration of titan dioxide nanoparticles in the polymer matrix. It was shown that rms roughness for non-polarized sample compositions is 60-100 nm, whereas for polarized samples after the corona discharge polarization, makes 20-40 nm, i.e. there takes place grinding of the structural elements. It is supposed that, in the composite there forms sufficiently high internal local field, due to the boundary charges, so under the influence of this field there were excited additional luminescent centers, and as a result, after the polarization there was observed the increase of luminescence intensity

Influence of magnetite nanoparticles on the dielectric properties of metal oxide/polymer nanocomposites based on polypropylene

Structure and dielectric properties of polymer nanocomposites based on isotactic polypropylene and iron oxide (Fe3O4) nanoparticles are studied. Distribution of magnetite nanoparticles in a polymer matrix was studied by scanning electron microscopy (SEM, Carl Zeiss). Dielectric properties of nanocomposites were examined by means of E7-21 impedance spectrometer in the frequency range of 102–106 Hz and temperature interval of 298–433 K. The frequency and temperature dependences of the dielectric permittivity ε, as well as the temperature dependence of log (ρ) were constructed. It is shown that introduction of the magnetite (Fe3O4) nanoparticles into a polypropylene matrix increases the dielectric permittivity of nanocomposites. An increase in the dielectric permittivity is explained by the increase in the polarization ability of nanocomposites. It is found that a decrease in the specific resistance with increasing temperature up to 318 K is associated with an increase in the ionic conductivity of nanocomposites. An increase in the resistance at temperatures higher than 358 K is due to the destruction of the crystalline phase of the polymer, as a result of which the distance between the Fe3O4 nanoparticles increases

Correction to: Influence of magnetite nanoparticles on the dielectric properties of metal oxide/polymer nanocomposites based on polypropylene (Russian Physics Journal, (2018), 60, 9, (1572-1576), 10.1007/s11182-018-1253-5)

The name of the first author should read A. М. Maharramov