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Biomedical subjects

A V Kolobov

Publications and source records attributed to A V Kolobov.

17 recordsLinked to original sources
PubMed2006

Pressure-induced site-selective disordering of Ge2Sb2Te5: a new insight into phase-change optical recording.

We demonstrate that , the material of choice in phase-change optical recording (such as DVD-RAM), can be rendered amorphous by the application of hydrostatic pressure. It is argued that this structural change is due to a very strong second-nearest-neighbor Te-Te interaction that determines the long-range order in the metastable cubic phase of and also to the presence of vacancies. This newly discovered phenomenon suggests that pressure is an important factor for the formation of the amorphous phase which opens new insight into the mechanism of phase-change optical recording.

Journal Article↗
PubMed2001

In situ X-ray absorption fine structure detection of reversible photoinduced anisotropy in amorphous selenium.

Photoinduced anisotropy in amorphous selenium ( a-Se) has been studied by in situ x-ray absorption fine structure spectroscopy. It is found that upon irradiation with linearly polarized light the chainlike fragments in a-Se are oriented with their c-axis perpendicular to the polarization plane of the inducing light. This chain orientation is reversible, correlates with optical anisotropy, and acts as a prelude to photoinduced anisotropic crystallization. This optically controlled reorientation of molecular fragments in a solid can be a basis for future novel devices.

Journal Article↗
PubMed2001

Local structure of Ge nanocrystals embedded in SiO2 studied by X-ray absorption fine structure.

Local structure of Ge nanocrystals embedded in SiO2 has been studied by X-ray absorption fine structure on the Ge K-edge. The XANES and EXAFS results indicate that Ge atoms in samples with the Ge concentration x=25-40 mol. % are coordinated with oxygen atoms, while they exist as amorphous Ge clusters in samples with x=60 mol. %. Upon annealing, completely relaxed crystalline Ge phase is formed for samples with x=60 mol. %, in contrast to the x=25-40 mol. % sample, which show little or no indication of Ge cluster formation. A possible mechanism of Ge nanocluster formation is discussed.

Journal Article↗
PubMed1996

[The etiology, pathogenesis and clinical picture of nonlactational mastitis].

The authors analyze an experience with treatment of 2750 patients with different forms of nonlactational mastitis. Special attention is given to peculiarities of the clinical course of the disease, importance of early diagnosis of the inflammation in the mammary gland. Pathogenetical treatment of different forms of nonlactational mastitis is substantiated. Dissection of all pathogenetically altered tissues is thought to be necessary in operative treatment of patients with purulent forms with the following histological investigation.

Adolescent↗
PubMed1976

[Stability of physico-chemical parameters of DNA during long-term storage].

DNA was extracted from calf thymus and sturgeon milt and purified of admixtures; this highly polymeric DNA was studied under conditions of its prolonged storage (for 1 1/2-2 years) at a temperature of 0-4 degrees C in 1 M NaCl in the form of a precipitate under a 70% ethanol and in the lyophilized state. It appeared that DNA obtained from the mentioned sources could be stored for at least 1 1/2 years under the said conditions without any significant damage of its polymeric properties or secondary structure. Although DNA from sturgeon milt had the initial physico-chemical indices similar to those of the thymus DNA, the former displayed much greater stability under the same storage condition, indicating stability of its molecular structure.

Animals↗