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Biomedical subjects

V V Stepanov

Publications and source records attributed to V V Stepanov.

15 recordsLinked to original sources
PubMed2001

Integrability and action operators in quantum Hamiltonian systems.

For a (classically) integrable quantum-mechanical system with two degrees of freedom, the functional dependence H=HQ(J1,J2) of the Hamiltonian operator on the action operators is analyzed and compared with the corresponding functional relationship H(p1,q1;p2,q2)=HC(J1,J2) in the classical limit of that system. The former converges toward the latter in some asymptotic regime associated with the classical limit, but the convergence is, in general, nonuniform. The existence of the function H=HQ(J1,J2) in the integrable regime of a parametric quantum system explains empirical results for the dimensionality of manifolds in parameter space on which at least two levels are degenerate. The analysis is carried out for an integrable one-parameter two-spin model. Additional results presented for the (integrable) circular billiard model illuminate the same conclusions from a different angle.

Journal Article↗
PubMed2001

[Content of myocardial catecholamines in patients with natural and acquired heart disease].

Approved by increased considered of adrenaline and nor-adrenaline in myocard of patients with native and acquisition of the heart diseases a speciality at part of the heart with largest functional working load. Taking increased levels of adrenaline and nor-adrenaline in the different parts of the heart at the sever patients with heart diseases usually with progressive heart's decompensation the recommendation preventive cardio-stimulation of the time of the surgery operation on the heart for correction of cardiac arrhythmic.

Aortic Valve↗
PubMed1985

[The causes of late hospitalization and analysis of mortality in children with malignant neoplasms].

The results of an analysis of histories of 118 pediatric cancer patients and data on 92 autopsied cases are presented. The reasons of late detection of tumors and hospitalization as well as the causes of death were studied. Most of the patients admitted to the hospital (97.5%) had stage III-IV malignancies. The lethality from solid tumors was 2.7 times that from hemoblastoses. Predominant sites of neoplastic growth versus age and a group at risk were identified. Identification of groups at risk, medical check-ups and setting up of specialized oncopediatric departments contribute to early diagnosis of cancer and lowering lethality in pediatric cancer patients.

Adolescent↗
PubMed1981

A case of Burkitt's lymphoma in Bulgaria.

A case of Burkitt's lymphoma is reported in a 5-year-old girl with involvement of the jaw and loosening of the teeth. Bilateral ovarian involvement occurred and subsequently dissemination to the CNS retrobulbar spaces causing exophthalmus, the thyroid, the myocardium, and other sites. The therapeutic plan included irradiation of the mandible and systemic chemotherapy. Due to the rapid deterioration of the patient's condition, irradiation was suspended at 1,200 rads. Chemotherapy was not administered since the bone marrow was completely replaced by lymphomatous tissue.

Bulgaria↗
PubMed1980

[Pulmonary complications in the surgery of advanced stages of mitral stenosis].

Pulmonary complications in late terms of mitral stenosis were studied by clinico-functional and patho-morphological investigations of lungs in 51 patients operated for mitral stenosis of the IV-V stage, with an additional retrospective analysis of autopsy records and case histories of 163 patients with mitral stenosis. It was noted that pulmonary complications in the postoperative period at late stages of mitral stenosis as a rather frequent event considerably aggravate the prognosis of surgery and are responsible for 40% of lethal outcomes. The pulmonary complications were found to be related to the preceding background of destructive changes in the lung tissue associated with lowered functional indices of the external respiration.

Adult↗