Size effects in chlorine doped PbSe thin films

The possibility of obtaining strongly degenerate (≈ 3·10²⁰ сm⁻³) PbSe thin films (d = 5 – 220 nm) with n-type conductivity by thermal evaporation in vacuum of PbSe crystals doped with PbCl₂, with subsequent condensation onto (001) KCl substrates was established. It was shown that the films had high homogeneity degree, no grain structure was observed. The thickness dependences of thermoelectric properties (the Seebeck coefficient S, the Hall coefficient RH and the electric conductivity σ) of thin films were obtained. In the thickness range d ≈ 5 ÷ 30 nm, oscillation properties were observed with growth of d that are attributable to electron gas quantization. The calculation of S(d) dependence on the assumption of size quantization with regard to contribution of several subbands and the thickness dependence of the Fermi energy was shown to be in agreement with the experimental data. In the region of d > 30 nm there was growth of S and σ with thickness, which is attributable to manifestation of classical size effect and interpreted in the framework of Fuchs-Sondheimer and Mayer theories

Dependences of thermoelectric properties on the thickness of thin films of indium doped lead telluride

Dependences of thermoelectric properties (the Seebeck coefficient S, the electric conductivity σ, the Hall coefficient RH, the carrier mobilityμ and the thermoelectric power P = S²·σ) on the thickness d (d = 10 – 255 nm) of thin films prepared by vacuum evaporation of indiumdoped PbTe crystals and subsequent condensation on (111) BaF₂ substrates were obtained. With decreasing thickness of films to d ≈ 40 nm, there is n- to p-type inversion of conduction which is related to a change in thermodynamic equilibrium conditions and partial reevaporation of lead and/or indium atoms. Extremes were found on the thickness dependences of properties at d₁ ≈ 20 nm which is indicative of hole gas quantization. In the range of thicknesses with n-type conduction there is a smooth change in thermoelectric properties with thickness which testifies to manifestation of classical size effect and is sufficiently well described in the framework of the Fuchs-Sondheimer theory

New information technologies in social studies: postnonclassical paradigm

The paper discusses topical issues of virtual reality technologies in social research, particularly when studying the processes of ethnic cultural identity, development of ethnic and racial attitudes using «virtual avatars» for managing ethnic conflicts, development of communication skills in representatives of different cultures using virtual collaboration and video conferencing. One of the key issues of the paper to discuss the necessity of post-non-classical paradigm as a conceptual framework for social research. Contemporary social studies require developing new methods, technologies and techniques at all levels of the research: from task setting to the development of new methods and result analysis. One of the most promising methods rapidly developed in recent years is virtual reality technology. The paper presents the analysis of more than 40 experimental studies performed using CAVE and HMD virtual reality systems. Their application is considered hereunder for the studies of verbal and nonverbal cues in communication, social skills training, treatment of social anxiety disorders and the development of new methods of cognitive behavioural therapy. Studies on interpersonal communication with virtual partners (i.e. «avatars») are considered. Factors affecting the communication quality of avatars, its visual and behavioural realism, problems of seeing virtual human as real partners for social interaction are discussed. Special attention is paid to the studies of racial and ethnic attitudes performed using virtual reality systems. The possibilities of practical applications of the VR technologies for shaping positive attitudes and development of communication skills in a sociocultural context are emphasized

Neuroendocrine Tumours: a Literature Review

Neuroendocrine tumours (NETs) are a heterogeneous group of malignant neoplasms with diverse morphology and nomenclature. Well-differentiated NETs were historically termed carcinoid tumours, which entailed abundant confusion and misclassification. Cross body-localised NETs have been described from the central nervous system, respiratory and gastrointestinal tracts, larynx, thyroid, skin, breast and urogenital system. The evidence on NET prevalence is diverse, with selected sources estimating a 0.5% rate among total malignancies diagnosed. Carcinoid syndrome is a known important associate of NETs. Its presence resulting from the amine and peptide hypersecretion often facilitates the NET diagnosis, and curative surgery becomes a treatment of choice, if technically feasible. Adjuvant therapy is ambiguous. When surgery is impractical due to a usually advanced NET at diagnosis, drug therapy is adopted to relief symptoms and control the disease

Novel highly charged silica-coated Tb(III) nanoparticles with fluorescent properties sensitive to ion exchange and energy transfer processes in aqueous dispersions

Novel silica-coated Tb(III) nanoparticles with high luminecsence were synthesized using the reverse microemulsion procedure. The quenching of luminescent properties of these nanoparticles can be achieved by ion exchange and energy transfer mechanisms. The quenching through the ion exchange of Tb(III) by H+ or La(III) is time dependent, indicating that the ion exchange is probably diffusion controlled. The quenching by Co(III) complex cations is achieved by the energy transfer mechanism and thus is not time dependent. The analysis of quenching data in Stern-Volmer cooordinates reveal the negative charge of the silica-coated Tb(III)-TCAS nanoparticles and several types of luminophoric species, located within the core and close to the surface of silica nanoparticles. © Copyright 2009 American Chemical Society

Assessment of the readiness of the «Titanic» to act in an emergens

The article presents the results of a literature review on the Titanic disaster. The work reflects the key points contributing to the deployment of a largescale tragedy: preparation of the vessel and crew for the tragedy, the device of the steamer, as well as moments related to rescue measuresВ статье изложены результаты обзора литературы, посвященной катастрофе «Титаника». В работе отражены ключевые моменты, способствующие развертыванию крупномасштабной трагедии: подготовка судна и экипажа к трагедии, устройство парохода, а также моменты, касающиеся проведения спасательных мероприятий

Hepatocellular Carcinoma: Aetiology and Mechanisms of Development. A Literature Review

Liver cancer remains a global challenge of healthcare, with the incidence growing worldwide. According to various authors, over 1 million patients will be diagnosed with liver cancer each year by 2025. The molecular pathogenesis of HCC varies with respect to genotoxic lesions and aetiologies. Although our understanding of the HCC pathophysiology and drivers tends to improve, it is still distant from translation into clinical practice. About 25 % of HCC cases are associated with variant mutations. HCC pathophysiology is a complex multi-step process. The interaction of various factors underlies the early stages of malignant hepatocyte transformation towards the development of HCC. Overall, about 20–25 % of HCC patients have at least one potential driver mutation. Obesity should also be noted as being associated with a higher risk of HCC and various other cancers. Despite many issues in the HCC pathogenesis being already known, the unresolved questions remain. Modern molecular genetic diagnostics and animal modelling of malignant tumours are expanding our horizons of knowledge in this field

Research of complexing abilities of antiviral azolotriazins and azolopyrimidines towards magnesiun ions

The article presents the results of the research of complexing abilities of derivatives of azolotriazines and azolopyrimidines with antiviral activity towards magnesium ions. The turbidimetric method was used. During the experiment, the coefficients of the complexing activity of the reviewing substances in a certain concentration were calculated; conclusions about the significance of the measurements were made.В статье изложены результаты исследования комплексообразующих свойств по отношению к ионам магния производных азолотриазинов и азолопиримидинов, обладающих противовирусной активностью. В работе использовался турбидиметрический метод. В ходе эксперимента были вычислены коэффициенты комплексообразующей активности исследуемых веществ заданной концентрации, сделаны выводы о значимости полученных измерений

Остеоартрит – аспекты фармакотерапии

The main goal of management of patients with osteoarthritis (OA) is analgesic and anti-inflammatory therapy, deceleration of the progression of the disease, and improvement of quality of life. Fast-acting symptomatic drugs (analgesics and nonsteroidal anti-inflammatory drugs (NSAIDs)) and sustained-release structure-modifying drugs (chondroitin sulfate, glucosamine sulfate, their combination, piascledine, diacerein) are used to treat OA. The European Society for Clinical and Economic Aspects of Osteoporosis and Osteoarthritis (ESCEO)) has analyzed the proposals of a number of expert groups and elaborated a consensus on the management of patients with OA: it has recommended the use of sustained-release drugs just in early OA.The article gives the data of comparative studies of a new Russian chondroprotector, the active ingredient of which is a bioactive extract from small sea fish, which contains alflutop. It evaluates the analgesic and anti-inflammatory effects and acute and chronic toxicity on experimental animal models and the preliminary results of therapy with the new drug in patients with OA in the large and small joints. Основная цель ведения пациентов с остеоартритом (ОА) – обезболивающая и противовоспалительная терапия, замедление прогрессирования болезни и улучшение качества жизни. Для лечения ОА используются симптоматические средства быстрого действия (анальгетики и нестероидные противовоспалительные препараты, НПВП) и структурно-модифицирующие препараты замедленного действия (хондроитина сульфат, глюкозамина сульфат, их комбинация, пиаскледин, диацереин). Европейское общество по клиническим и экономическим аспектам остеопороза и остеоартрита (European Society for Clinical and Economic Aspects of Osteoporosis and Osteoarthritis, ESCEO) проанализировало предложения ряда экспертных групп и выработало консенсус по ведению больных ОА: рекомендовано назначать медленнодействующие препараты уже на ранних стадиях ОА.В статье приведены данные сравнительных исследований нового отечественного «хондропротектора», активным компонентом которого является биоактивный экстракт из мелкой морской рыбы, с препаратом алфлутоп. Оценивали анальгетический, противовоспалительный эффект, острую и хроническую токсичность на экспериментальных моделях животных, а также предварительные результаты терапии новым препаратом у больных ОА крупных и мелких суставов.