Spatial optical solitons in nonlinear photonic crystals

We study spatial optical solitons in a one-dimensional nonlinear photonic crystal created by an array of thin-film nonlinear waveguides, the so-called Dirac-comb nonlinear lattice. We analyze modulational instability of the extended Bloch-wave modes and also investigate the existence and stability of bright, dark, and ``twisted'' spatially localized modes in such periodic structures. Additionally, we discuss both similarities and differences of our general results with the simplified models of nonlinear periodic media described by the discrete nonlinear Schrodinger equation, derived in the tight-binding approximation, and the coupled-mode theory, valid for shallow periodic modulations of the optical refractive index.Comment: 15 pages, 21 figure

THE CHOICE OF POLYPROPYLENE ENDOPROSTHESIS FOR ABDOMINAL WALL PLASTY

The study (on 27rabbits) of postponed tissue reaction of abdominal wall was done after web space plasty of standard, light and superlight polypropylene endoprostheses on 30th, 60th and 120th days. It was stated, that the standard polypropylene prosthesis was the most suitable for endoprosthesis replacement of abdominal wall in strangulated ventral hernia. The light polypropylene endoprosthesis should be used in the uncomplicated hernia. The superlight polypropylene prosthesis should be applied for preventive endoprosthesis replacement of abdominal wall in its anatomico-functional insufficiency

INFLUENCE OF LIFTING OF MUSCULAR APONEUROTIC TISSUES OF THE HYPOGASTRIUM AREA ON QUALITY OF LIFE IN ABDOMINOPLASTY PATIENTS

An analysis of complex clinical and ultrasonic investigations of the abdominal wall and the following surgery in 42 women with ventral hernia of big size accompanied by the ptosis of the abdomen was made. The patients were divided into two groups, each consisting of 21 patients. The endoprosthesis replacement of defect of the abdominal wall was made with standard polypropylene implant in the first group. The endoprosthesis replacement was complemented by lifting of muscular aponeurotic tissues of the hypogastrium using the implant of the original construction in the second group. The polypropylene endoprosthesis includes the main flap (15×15 cm) with rounded corners and the additional flap (5×40 cm) as a broad band situated at the lower edge of main flap in across-track direction. The increase of physical component of health was noted in 1,8 times in the second group patients and psychological component raised in 2,5 times