Raman response of quantum critical ferroelectric pb-doped srtio3

A quantum paraelectric SrTiO3 is a material situated in close proximity to a quantum critical point (QCP) of ferroelectric transition in which the critical temperature to the ferroelectric state is suppressed down to 0 K. However, the understanding of the behavior of the phase transition in the vicinity of this point remains challenging. Using the concentration x of Pb in solid solution Sr1−x Pbx TiO3 (PSTx) as a tuning parameter and applying the combination of Raman and dielectric spectroscopy methods, we approach the QCP in PSTx and study the interplay of classical and quantum phenomena in the region of criticality. We obtain the critical temperature of PSTx and the evolution of the temperature-dependent dynamical properties of the system as a function of x to reveal the mechanism of the transition. We show that the ferroelectric transition occurs gradually through the emergence of the polar nanoregions inside the non-polar tetragonal phase with their further expansion on cooling. We also study the ferroelastic cubic-to-tetragonal structural transition, occurring at higher temperatures, and show that its properties are almost concentration-independent and not affected by the quantum criticality.Fil: Linnik, Ekaterina D.. Southern Federal University; RusiaFil: Mikheykin, Alexey S.. Southern Federal University; RusiaFil: Rubi, Diego. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Unidad Ejecutora Instituto de Nanociencia y Nanotecnología. Unidad Ejecutora Instituto de Nanociencia y Nanotecnología - Nodo Constituyentes | Comisión Nacional de Energía Atómica. Unidad Ejecutora Instituto de Nanociencia y Nanotecnología. Unidad Ejecutora Instituto de Nanociencia y Nanotecnología - Nodo Constituyentes; ArgentinaFil: Shirokov, Vladimir B.. No especifíca;Fil: Mezzane, Daoud. No especifíca;Fil: Kondovych, Svitlana V.. No especifíca;Fil: Lukyanchuk, Igor A.. No especifíca;Fil: Razumnaya, Anna G.. Southern Federal University; Rusi

Capsule endoscopy for screening colon tumors

Department of General Surgery with a course of endoscopy of the Federal State Budgetary Educational Institution of Higher Education and Medical University of the Ministry of Health of Russia, Leningrad Regional Oncologic Dispensary, Department of Faculty Surgery. prof. A.A. Rusanov of the Federal State Budgetary Educational Institution of Higher Education and Medical University of the Ministry of Health of Russia, Sankt-Petersburg, Russia, Al XIII-lea Congres al Asociației Chirurgilor „Nicolae Anestiadi” și al III-lea Congres al Societății de Endoscopie, Chirurgie miniminvazivă și Ultrasonografie ”V.M.Guțu” din Republica MoldovaIntroduction: Most of the colon tumors are detected in the later stages. The introduction of new, minimally invasive technologies into clinical practice allows to improve the results of the diagnosis of neoplasms. Material and methods: Capsule endoscopy is a procedure for colon examination using a miniature camera, which takes more than 10,000 images of colon at a speed of 4 to 24 frames per second. For the patient, the procedure itself does not cause discomfort. On the day of the study, the patient may do his usual activities. The indications for capsular examination of the colon may be suspected tumor of the colon, a positive test of fecal occult blood test, and the patient is over 50 years old. We made a decision to launch a pilot project for screening the colon among health care workers in Oncology Dispensary of Leningrad Region. Results: In the years 2017-2018, we performed 67 capsule colon examinations for medical workers who had not previously performed a colonoscopy. A total colon investigation was performed in 58 patients (87%). Among these patients 2 malignant tumors of the colon (3.5%) were detected. Colon epithelial neoplasia was detected in 11 patients (19%). These findings contributed to perform colonoscopy with endoscopic polypectomy. Conclusion: Capsule endoscopy of the colon can be used for examination, in cases where colonoscopy is not possible. Capsule endoscopy helps to convince the patient of the need to perform colonoscopy. Capsule endoscopy is a safe method for screening colorectal cancer

Cellular Origins of EGFR-Driven Lung Cancer Cells Determine Sensitivity to Therapy

Targeting the epidermal growth factor receptor (EGFR) with tyrosine kinase inhibitors (TKIs) is one of the major precision medicine treatment options for lung adenocarcinoma. Due to common development of drug resistance to first- and second-generation TKIs, third-generation inhibitors, including osimertinib and rociletinib, have been developed. A model of EGFR-driven lung cancer and a method to develop tumors of distinct epigenetic states through 3D organotypic cultures are described here. It is discovered that activation of the EGFR T790M/L858R mutation in lung epithelial cells can drive lung cancers with alveolar or bronchiolar features, which can originate from alveolar type 2 (AT2) cells or bronchioalveolar stem cells, but not basal cells or club cells of the trachea. It is also demonstrated that these clones are able to retain their epigenetic differences through passaging orthotopically in mice and crucially that they have distinct drug vulnerabilities. This work serves as a blueprint for exploring how epigenetics can be used to stratify patients for precision medicine decisions

Flat bands in topological media

Topological media are systems whose properties are protected by topology and thus are robust to deformations of the system. In topological insulators and superconductors the bulk-surface and bulk-vortex correspondence gives rise to the gapless Weyl, Dirac or Majorana fermions on the surface of the system and inside vortex cores. Here we show that in gapless topological media, the bulk-surface and bulk-vortex correspondence is more effective: it produces topologically protected gapless fermions without dispersion -- the flat band. Fermion zero modes forming the flat band are localized on the surface of topological media with protected nodal lines and in the vortex core in systems with topologically protected Fermi points (Weyl points). Flat band has an extremely singular density of states, and we show that this property may give rise in particular to surface superconductivity which could exist even at room temperature.Comment: 9 pages, 5 figures, version to appear in JETP Letter

Metal-insulator transitions: Influence of lattice structure, Jahn-Teller effect, and Hund's rule coupling

We study the influence of the lattice structure, the Jahn-Teller effect and the Hund's rule coupling on a metal-insulator transition in AnC60 (A= K, Rb). The difference in lattice structure favors A3C60 (fcc) being a metal and A4C60 (bct) being an insulator, and the coupling to Hg Jahn-Teller phonons favors A4C60 being nonmagnetic. The coupling to Hg (Ag) phonons decreases (increases) the value Uc of the Coulomb integral at which the metal-insulator transition occurs. There is an important partial cancellation between the Jahn-Teller effect and the Hund's rule coupling.Comment: 4 pages, RevTeX, 3 eps figure, additional material available at http://www.mpi-stuttgart.mpg.de/docs/ANDERSEN/fullerene

Endoscopic treatment of patients with early forms of gastric cancer

Leningrad regional oncological dispensary, Russia, Al XIII-lea Congres al Asociației Chirurgilor „Nicolae Anestiadi” și al III-lea Congres al Societății de Endoscopie, Chirurgie miniminvazivă și Ultrasonografie ”V.M.Guțu” din Republica MoldovaBackground: Currently, most patients with gastric tumors are detected in late stages. Early diagnosis is a major factor in improving treatment outcomes. On the other hand, patients who are diagnosed on early stages often receive aggressive treatment and are not subjects to less invasive interventions. Material and Methods: In our clinic we have been using endoscopic surgery for early gastric cancer since 2009. Japanese colleagues are the most experienced in this kind of treatment that is why we follow the recommendations of Japanese Gastric Cancer Association (JGCA). The main criterion provided that endoscopic removal is possible is the depth of tumor invasion. We evaluate the depth of invasion primarily by endoscopic ultrasonography. According to our data the accuracy of this method is 94%. The main operation used for the treatment of early gastric cancer is endoscopic submucosal dissection (ESD). Its main advantages are single block resection within healthy tissues and adequate morphological assessment of the removed tumor. In the last ten years we have performed 148 ESD (145 patients) for early forms of gastric cancer. Surgeries were radical in 95% of cases. Results:There were no cases of postoperative mortality. Progression of the disease was noted only in one patient. These endoscopic surgeries have proved to be effective, safe and reasonable in treating early gastric cancer. Conclusions: Thus, endoscopic surgery significantly reduces the cost of treatment and hospital stay (average - 3.7 days), facilitates rehabilitation and improves the quality of patients’ life

Plasmids From Soil Streptomyctes

An investigation on a small collection of Streptomyces   strains, freshly isolated from soil, showed the presence of plasmids in 25% of the cultures. Two plasmids were subjected to restriction enzymes