562 research outputs found
Vibrational and Thermal Properties of ZnX (X=Se, Te): Density Functional Theory (LDA and GGA) versus Experiment
We calculated the phonon dispersion relations of ZnX (X=Se, Te) employing ab
initio techniques. These relations have been used to evaluate the temperature
dependence of the respective specific heats of crystals with varied isotopic
compositions. These results have been compared with mea- surements performed on
crystals down to 2 K. The calculated and measured data are generally in
excellent agreement with each other. Trends in the phonon dispersion relations
and the correspond- ing densities of states for the zinc chalcogenide series of
zincblende-type materials are discussed.Comment: 10 pages, submitted to PR
Cerenkov generation of high-frequency confined acoustic phonons in quantum wells
We analyze the Cerenkov emission of high-frequency confined acoustic phonons
by drifting electrons in a quantum well. We find that the electron drift can
cause strong phonon amplification (generation). A general formula for the gain
coefficient, alpha, is obtained as a function of the phonon frequency and the
structure parameters. The gain coefficient increases sharply in the short-wave
region. For the example of a Si/SiGe/Si device it is shown that the
amplification coefficients of the order of hundreds of 1/cm can be achieved in
the sub-THz frequency range.Comment: 4 pages, 2 figures. Submitted to AP
Recent discoveries in the cycling, growing and aging of the p53 field
The P53 gene and it product p53 protein is the most studied tumor suppressor, which was considered as oncogene for two decades until 1990. More than 60 thousand papers on the topic of p53 has been abstracted in Pubmed. What yet could be discovered about its role in cell death, growth arrest and apoptosis, as well as a mediator of the therapeutic effect of anticancer drugs. Still during recent few years even more amazing discoveries have been done. Here we review such topics as suppression of epigenetic silencing of a large number of non-coding RNAs, role of p53 in suppression of the senescence phenotype, inhibition of oncogenic metabolism, protection of normal cells from chemotherapy and even tumor suppression without apoptosis and cell cycle arrest
Recent progress in targeting cancer
In recent years, numerous new targets have been identified and new experimental therapeutics have been developed. Importantly, existing non-cancer drugs found novel use in cancer therapy. And even more importantly, new original therapeutic strategies to increase potency, selectivity and decrease detrimental side effects have been evaluated. Here we review some recent advances in targeting cancer
Electron-phonon interaction via Pekar mechanism in nanostructures
We consider an electron-acoustic phonon coupling mechanism associated with
the dependence of crystal dielectric permittivity on the strain (the so-called
Pekar mechanism) in nanostructures characterized by strong confining electric
fields. The efficiency of Pekar coupling is a function of both the absolute
value and the spatial distribution of the electric field. It is demonstrated
that this mechanism exhibits a phonon wavevector dependence similar to that of
piezoelectricity and must be taken into account for electron transport
calculations in an extended field distribution. In particular, we analyze the
role of Pekar coupling in energy relaxation in silicon inversion layers.
Comparison with the recent experimental results is provided to illustrate its
potential significance
On the Model Calculation of the Excitonic-Like States and Their Possible Role in Autocatalytic Processes
Robust stability in the problem of motion of an inverted pendulum with a vibrating suspension point
The physicochemical and sorption properties of such wastes of the agro-industrial complex of Turkmenistan as seed husks, tumbleweeds and cotton bolls have been studied as a potential raw material for the production of oil sorbents
Robust stability in the problem of motion of an inverted pendulum with a vibrating suspension point
The physicochemical and sorption properties of such wastes of the agro-industrial complex of Turkmenistan as seed husks, tumbleweeds and cotton bolls have been studied as a potential raw material for the production of oil sorbents
The Concept of Ecologically Oriented Progress and Natural Resource Preservation
The most important issue of scientific and technological progress is considering the environment challenges of industrial development. It means that the progress must be ecologically oriented and environmentally friendly. The most adequate concept for the approach to the issue of "man - society – nature" relations is the ontology of the noosphere - the idea of a common space for human beings and nature. It presents an ideal example of an optimistic attitude towards the coordination between accelerating the scientific and technological development and natural resource saving. However, to maintain the balance between human needs and environmental processes determined by this concept, it is essential to include the lean production training into technological development of society
Hypoxia-inducible factor: basic biology and involvement in cardiovascular pathology
Molecular epidemiological studies conducted to date reveal a close relationship between the polymorphism of the HIF system genes with a wide range of cardiovascular, inflammatory, and oncological diseases. The study of the HIF system can contribute to the discovery of new targets and methods of pharmacological effects for the treatment of cardiovascular, oncological, rheumatological, and endocrinological patholog
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