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Biomedical subjects

V N Denisov

Publications and source records attributed to V N Denisov.

At least 19 recordsLinked to original sources
PubMed2004

Polymerization of nitrogen in sodium azide.

The high-pressure behavior of nitrogen in NaN(3) was studied to 160 GPa at 120-3300 K using Raman spectroscopy, electrical conductivity, laser heating, and shear deformation methods. Nitrogen in sodium azide is in a molecularlike form; azide ions N(3-) are straight chains of three atoms linked with covalent bonds and weakly interact with each other. By application of high pressures we strongly increased interaction between ions. We found that at pressures above 19 GPa a new phase appeared, indicating a strong coupling between the azide ions. Another transformation occurs at about 50 GPa, accompanied by the appearance of new Raman peaks and a darkening of the sample. With increasing pressure, the sample becomes completely opaque above 120 GPa, and the azide molecular vibron disappears, evidencing completion of the transformation to a nonmolecular nitrogen state with amorphouslike structure which crystallizes after laser heating up to 3300 K. Laser heating and the application of shear stress accelerates the transformation and causes the transformations to occur at lower pressures. These changes can be interpreted in terms of a transformation of the azide ions to larger nitrogen clusters and then polymeric nitrogen net. The polymeric forms can be preserved on decompression in the diamond anvil cell but transform back to the starting azide and other new phases under ambient conditions.

Journal Article↗
PubMed1987

[Catalytic and immunochemical properties of ferritin conjugates with horseradish peroxidase].

The human spleen ferritin--horseradish peroxidase conjugate (HRP--Fer) was synthesized by periodate oxidation of the enzyme carbohydrate fragment. The protein fraction containing 1-2 peroxidase molecules and characterized by kinetic homogeneity was obtained in the peroxidatic ortho-dianisidine (o-DA) oxidation reaction. Gel diffusion precipitation of HRP--Fer with peroxidases and ferritin antibodies was carried out. The precipitation confirms the retention by peroxidase and ferritin of their antigenic properties. The kinetics of peroxidatic oxidation of o-DA by the HRP--Fer conjugate was studied within the temperature interval of 15-37 degrees C. The value of catalytic constant for this reaction exceeds that for native peroxidase 1.75-fold. A kinetic analysis of thermal inactivation of peroxidase and its conjugate was performed within the temperature range of 40-65 degrees C. The effective rate constants of inactivation obtained from the first order equation are higher for HRP--Fer than for the native enzyme. The effect of pH on the rates of inactivation of HRP--Fer and the non-modified enzyme was studied at 50 degrees C. The enzyme and its conjugate were shown to stabilize in acid media. The HRP--Fer conjugate can be used as an effective tool in immunoenzymatic assays of ferritin.

Catalysis↗
PubMed1978

[Change in the density of surface lymphocyte receptors and in the level of serum immunoglobulins in chronic lympholeukosis].

Using the complex of methods for recognition of surface lymphocyte receptors the authors examined 42 patients with chronic lymphatic leukemia and 30 healthy individuals. The reduced density of receptors on lymphocyte surface or their total absence is characteristic of the whole group of patients with chronic lymphatic leukemia. This atypism of leukemia lymphocytes is augmented in greater rate of neoplastic cells growth. Total synthesis of serum immunoglobulins in chronic lymphatic leukemia is found to be lowered, the fall being more sharp in increased amount of lymphocytes in peripheral blood.

Adult↗
PubMed1977

[Advantages in immunofluorescence of dichlortriazinylaminofluorescein conjugates isolated by single-step gel filtration].

The author describes a simple method obtaining dichlortriazinylaminofluoresceine (DCTAF) conjugates to human immunoglobulins and separation of their optimally labeled fractions. The single-stage method of the conjugate release from the nonbound flurorchrome and of a simultaneous separation of the optimally labeled fractions was carried out on Sephadex G-25 at pH 5.6--6.6 and at low ionic power of the eluate. Proteins overloaded with the dye are sorbed on gel according to their isoelectrical points.

Chromatography, Gel↗
PubMedDate not supplied

[New information technologies in the management of emergency health services].

Novel information computer system introduced at the first aid station of Novosibirsk has improved effectiveness of ambulance transport and emergency teams; quickened the process of reporting information to the head of the station and higher medical institutions as well as responding to requests; facilitated control over continuous education of the staff and planning of relevant educational programs.

Ambulances↗
PubMedDate not supplied

[The role of prevention in decreasing endocrine pathology].

Time course of changes in the incidence of thyroid diseases and their association with other noncontagious chronic diseases (NCCD) have been evaluated among therapeutic patients hospitalized at Research Center for Clinical and Experimental Medicine of Siberian Division of Russian Academy of Medical Sciences in 1983-1995. The incidence of thyroid diseases was low in 1983, when prevention of iodine-deficiency diseases was a state program. In 1989, when iodine deficiency prevention was reduced, the incidence of cases with enlarged gland and its dysfunction has drastically increased. In 1995, when the system of population protection from endemic goiter virtually ceased to function, the incidence of thyroid diseases increased, including such serious diseases as diffuse toxic goiter, nodular goiter, primary hypothyrosis, and autoimmune thyroiditis; the number of patients in whom thyroid diseases were concomitant with other NCCD increased. These results demonstrate the principal significance of the preventive trend in public health.

Adult↗
PubMedDate not supplied

[Systemic and cerebral hemodynamic status of flight personnel under moderate hypoxia].

For the purposes of medical expertise the state of systemic and cerebral hemodynamics has been investigated in 66 pilots with autonomic-vascular instability and in 36 healthy subjects exposed to moderate hypoxia (in an altitude chamber). The pilots have shown noticeable tachycardia or systolic hypertension as well as certain changes in cardiac output and stroke volume. These alterations have been accompanied by rheoencephalographic changes of two types one of which can be regarded as an adverse response of cerebral circulation to hypoxia. It is concluded that the study of systemic and cerebral circulation in hypoxia yields an important diagnostic information that allows better expertise estimates.

Adult↗