Phase states, microstructure and dielectric characteristics of solid solutions (1 - x)NaNbO3 - xCa2Nb2O7 and (1 - x)NaNbO3 - xSr2Nb2O7.

Ceramics of binary systems solid solutions (1 - x)NaNbO3 - xCa2Nb2O7 and (1 - x)NaNbO3 - xSr2Nb2O7 with non-isostructural extreme components were prepared by the solid-phase reactions technique with the following sintering using conventional ceramic technology. It was found that ceramics with x ≤ 0.2 have a perovskite structure. Layered type of structure predominates in the concentration range 0.2 < x ≤ 1. Phase diagrams of both systems at room temperature have been determined in the perovskite area. It was shown that this area contains two concentration regions with the different crystal structures and the morphotropic phase boundary between them. Microstructure and dielectric characteristics of selected solid solutions were investigated. The influence of technological regulations, such as mechanical activation and variation of sintering temperatures, on the formation of the microstructure and dielectric characteristics was studied for the individually selected concentrations (x = 0.1 and x = 0.25). Dielectric characteristics of ceramics revealed the presence of the Maxwell-Wagner polarization and its corresponding relaxation in the solid solutions (1 - x)NaNbO3 - xCa2Nb2O7 at x > 0.20.

Intercalation of water molecules from the air into perovskite and layered structures formed in the system of NaNbO3-Ca2Nb2O7.

The study results of the perovskite solid solution and layered compounds formed in the system of (1-х)NaNbO3-xCa2Nb2O7, x = 0.10, 0.25, 0.55, 1.00 are presented. The objects of the study are obtained by solid-phase synthesis, followed by sintering using conventional ceramic technology. The study of dielectric spectra has revealed their anomalous behavior in the temperature range of 360-450 K, most pronounced in the composition with x = 0.25. To explain the anomalies in these objects, a microstructural analysis of ceramics, thermogravimetry, high-temperature powder X-ray diffraction, and IR spectroscopy heve been performed. It has been established that the anomalies of the dielectric spectra in the indicated range are due to the adsorption of water from the air, its dissociation and the incorporation of the OH2 and OH- oxyhydryl groups into the crystal lattice of the solid solution and the compounds. In a compound located near the boundary between solid solutions and layered compounds, the process of water adsorption is accompanied by the appearance of an intermediate incommensurate phase and ends with the formation of a new compound.

Case Report: Education and training of RTTs for radiation oncology departments in Russia.

Modern radiotherapy is performed with sophisticated equipment that requires highly qualified professionals. In the Russian Federation the responsibilities of Radiation Therapy Technologists (RTTs) are carried out by medical nurses who receive on-the-job training. The article discusses the problems of RTT education and training, describes our own teaching experience and suggests further development for the national RTT education system in Russia.

The impact of multi-walled carbon nanotubes with different amount of metallic impurities on immunometabolic parameters in healthy volunteers.

The impact of two types of multi-walled carbon nanotubes (MWCNTs) (12-14 nm) with different content of metallic impurities (purified and unpurified nanotubes) on peroxidation processes, the status of immune cells in healthy volunteers and gene expression combined to pathway analysis was studied in vitro. From the study it was shown that the main mechanism of action for both types of MWCNTs is induction of oxidative stress, the intensity of which is directly related to the amount of metallic impurities. Unpurified MWCNTs produced twice as high levels of oxidation than the purified CNTs inducing thus more intense mitochondrial dysfunction. All the above were also verified by gene expression analysis of 2 different human cellular cultures (lung epithelium and keratinoma cells) and the respective pathway analysis; modulation of genes activating the NFkB pathway is associated to inflammatory responses. This may cause a perturbation in the IL-6 signaling pathway in order to regulate inflammatory processes and compensate for apoptotic changes. A plausible hypothesis for the immunological effects observed in vivo, are considered as the result of the synergistic effect of systemic (mediated by cells of the routes of exposure) and local inflammation (blood cells).

[SPECT/CT radiation in treatment of bone metastases of osteosarcoma].

The aim of this study was to demonstrate the diagnostic ca- pabilities to control effects of radiotherapy treatment in patient with osteosarcoma bone metastases by SPECT-CT method. There was conducted SPECT/CT treatment monitoring of the patient with bone metastases of osteosarcoma after external radiotherapy and cyber knife. There were detected changes in the SPECT/CT-pictures of treated bones osteosarcoma metasta- ses. The SPECT/CT has proven as a reliable method of dynam- ic control at radiotherapy. Treatment effect all of these methods was to reduce or to get absent accumulation of bone-tropic radiopharmaceutical labeled with 99mTc-technetium. SPECT/ CT study was a demonstrative method for early determination of pathological metabolism degree in bone metastases of os- teosarcoma. SPECT/CT was an effective method of treatment monitoring of bone metastases after radiotherapy.

[Conformal radiotherapy for prostate cancer].

Data are presented on a retrospective comparison of the results of remote radiotherapy and combined treatment of prostate cancer (T2T4NxM0) (88) at the Center's Clinics (1999-2003). Diagnosis was confirmed by morphological evidence: T2NxM0 (group 1)--18.2%, T3aNx M0 (group 2)--53.4%, T3bNx M0 (group 3)--18.2%, T4NxM0--10.2% (group 4). In group 1 (n=37), contemporary radiotherapy was administered--TTD--up to 44 Gy (stage I) and up to 66-70 Gy (stage II). In group 2 (n=51), contemporary radiotherapy was supplemented with inhalation of radioprotector GGS-9--TTD--up to 44 Gy plus GGS-9 (stage I) and up to 72-76 Gy plus conformaton radiotherapy (3D CRT) (stage II). When GGS-9 was used at stage I the rate of acute radiation injury dropped from 56.7% in group 1 to 11.7% in group 2, (p=0.0001). The frequency of late-onset injury was also lower in patients receiving 3D CRT (13.5 and 3.9%, respectively) (p=0.01). Local and biological relapse occurred frequently after contemporary radiotherapy (27%) as compared with conformation one (5.8%). The latter treatment was followed by higher 5-year recurrence-free survival (94.2%) as compared with contemporary radiotherapy (73%), (p=0.0001). Owing to use of 3D CRT, dose distribution was improved as volume and dosage for organs at risk of irradiation decreased, while TTD increased up to 72-76 Gy unaccompanied by a rise in early-onset injuries. On the contrary, late-onset radiation damage fell down.

[The development of radiotherapeutic techniques at the beginning of the 21st century in Blokhin Russian Oncological Research Center of Russian Academy of Medical Sciences].

The article describes the development of radiotherapeutic techniques in Blokhin Russian Oncological Scientific Center of Russian Academy of Medical Sciences at the end of the 20th and the beginning of the 21st centuries. Such developmental directions in radiation oncology as the development of non-conventional modes of radiation dose fractioning, the development of new radiotherapeutic techniques based on volumetric 3D dosimetric radiotherapy planning, the perfection of combined (contact plus distant) radiotherapy, the use of multidirectional radiomodifying agents, the application of radiotherapy as a part of combined and complex treatment with chemotherapy and surgery in different tumoral sensitivity to conservative treatment, are considered in the article. Immediate and long-term results achieved at the institution by the use of radiotherapy alone or as a part of combined or complex treatment in cases with certain malignant tumor localizations are described.

[Thermoradiochemotherapy of inoperable soft-tissue sarcoma].

Three groups of patients with inoperable soft-tissue sarcoma received preoperative radiotherapy (57), thermoradiotherapy (102) and thermoradiochemotherapy (16) (n=175). Five year recurrence-free survival in group 1 was 37+/-7%, group 2 48+/-6%, and group 3 - 56+/-1,7%. Patients survived 5 years and more in group 3 (60+/-2%), group 2 - 50+/-7%, and group I 44+/-8% (p>0.05). Local hyperthermia used in conjunction with radio- and chemoradiotherapy was followed by a significant rise in the rate of complete and partial tumor regression.

[Radiotherapy as a component of treatment for Ewing's sarcoma].

The main stages of development of such conservative modalities as radio- and chemoradiotherapy for localized Ewing's sarcoma are discussed. Factors affecting five-year overall and recurrence-free survival of patients treated with chemoradiotherapy are presented.

[The surface membrane charge of bacteria and its role in serine proteinase secretion by Bacillus subtilis cells]. / Poverkhnostnyi zariad membran bakterii i ego rol' v sekretsii serinovoi proteinazy kletkami Bacillus subtilis.

Univalent, bivalent and trivalent metal cations increase the fluorescence yield of 9-aminoacridine in the suspensions of chromatophores of the purple nonsulfur bacterium Rhodospirillum rubrum isolated thylakoid membranes and cells of cyanobacterium Anabaena variabilis, cells Bacillus subtilis. The active cation concentrations increase about in 10 times with the decrease of their valency by one. It points to the fact that the changes in 9-aminoacridine fluorescence serve for the monitoring of the surface charge of bacterial membranes. The negative surface charge of B. subtilis cells increases before the onset of the serine protease secretion. The metal cations stimulate the serine protease secretion by B. subtilis cells, the stimulating effect correlates with the action of cations on the 9-aminoacridine fluorescence yield. It is suggested that the surface charge of cytoplasmic membrane regulates the formation and release of serine protease by the cells of B. subtilis.

[Activity of methane-oxidizing bacteria in the adsorbed state]. / Aktivnost' metanokisliashchikh bakterii v adsorbirovannom

Adsorption of pure cultures of methane oxidizing bacteria, Methylosinus trichosporium 20 and Methylococcus ucrainicus 21, on glass and coal was studied; the former strain was sorbed on both sorbents, the latter strain was sorbed on coal but not on glass. The rate of methane oxidation by the cells of adsorbed microorganisms was higher than in the case of free cells, and increased with a decrease in dimensions of the sorbent particles.