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Biomedical subjects

A V Nesterov

Publications and source records attributed to A V Nesterov.

5 recordsLinked to original sources
PubMed2006

Generation of inhomogeneously polarized laser beams by use of a Sagnac interferometer.

A principal scheme for an external cavity technique for changing the polarization of a laser beam based on a modified Sagnac interferometer is proposed. The modified Sagnac interferometer includes standard optical components: a displacement polarizing beam splitter, an angle reflector, and a Dove prism. The radially polarized beams, obtained with the help of the developed scheme, allow the generation of a longitudinally polarized electric field by sharp focusing. The phase correction of radially polarized modes of higher orders leads to increasing the longitudinal field in the focus of the beam.

Journal Article↗
PubMed2005

Vector solution of the diffraction task using the Hertz vector.

A large class of diffraction problems can be solved on the basis of the Huygens principle. However, methods of solving diffraction problems based on this principle exhibit narrow boundaries of applicability. The goal of the present work is to offer a relatively simple physically based and mathematically strict "dipole wave" vector theory of non-paraxial diffraction of electromagnetic radiation which allows analytical solutions of typical diffraction problems. The suggested theory logically retains the wave approach used in the Kirchhoff method and does not exhibit strict limitations to applicability inherent in the Kirchhoff integral. The diffraction problem is solved by using the Hertz vector in the Kirchhoff integral instead of the field vector. The method efficiency is illustrated in several examples. Analytical solutions of diffraction base problems have been obtained for linearly polarized radiation on an infinite slit and on various-shaped holes at an arbitrary angle of incidence and polarization. It was shown the possibility of vector addition particular solutions to obtain diffraction patterns from several holes. The diffraction of radiation with azimuthal and radial directions of polarization on a ring slit is also considered. The main qualitative feature of the obtained solutions is the presence of "poles" one or two points of zero field in the diffraction pattern which are superimposed on the common system of light and dark fringes. The poles are located along electrical field vector directions. The vector analytical formulas describing the propagation of some laser beams in the free space have been obtained too. The solutions of the diffractive problems satisfy the Maxwell equations and the reciprocity principle.

Journal Article↗
PubMed2001

Design and application of low-frequency ultrasound and its combination with laser radiation in surgery and therapy.

Further development of combined laser-ultrasonic medical technologies is presented. An analysis is made of the main effects produced by low-frequency ultrasound on biological tissues. These effects include cavitation, acoustic streamings, acoustic pressure, and mechanical influence. Possible application of low-frequency ultrasound is considered in regard to tumor therapy, bactericidal treatment of infectious tissues, and spray treatment of head and neck wounds. Some limitations of ultrasound application in medicine are discussed, and the feasibility of combining laser radiation with ultrasound is studied. A number of new laser-ultrasonic combinations are put forward and developed. They embrace the combination of photodynamic therapy with ultrasonic tumor therapy (sonophotodynamic therapy), laser-ultrasonic wound treatment (spray treatment), and laser-ultrasonic drug delivery (photophonophoresis). Some of the above-mentioned technologies were tested experimentally, and the results obtained are considered.

Combined Modality Therapy↗
PubMed1990

[Selection of the method of plastic surgery of the abdominal wall in ventral hernia].

Materials on surgical treatment of 365 patients with various types of ventral hernias are discussed. The authors describe original methods of ventroplasty which they developed and approved . The methods comprise duplication of the whole peritoneal-muscular-cicatricial-aponeurotic complex of the abdominal wall by means of a double-row suture passed through all these layers and application of a third reinforcing row of sutures; whenever necessary, the operation is divided into two stages. Preoperative compression training of the abdomen is conducted in cases of a large hernia. Attention is focused on the need to choose the method of plasty for each individual patient, which makes it possible to avoid serious complications and fatal outcomes and produce good results of the treatment. Recurrences in large ventral hernias occurred in 8% of cases.

Abdominal Muscles↗