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Using amplified femtosecond pulses at a wavelength of 1028 nm, the second harmonic is generated at a wavelength of 514 nm by composite polymer films containing D-π-A (push–pull) chromophores with quadratic optical nonlinearity. It is shown that these films are photostable with respect to laser pulses having peak intensities of up to 11.6 GW/cm2. The effective generation of the second harmonic is observed in a wide range of pump beam incidence angles (20°–80°) with a maximum in the vicinity of 60°.

To compare the effectiveness of two surgical techniques in patients with pilonidal sinus.There were 117 patients with pilonidal sinus divided into 2 groups depending on surgical approach: main group - Limberg Flap reconstruction (Mean length of hospital-stay in the main group was 8.2 days, in the control group - 5.4 days. Pain syndrome was more significant after 1 postoperative day in the main group. Three days later, severity of pain was similar in both groups. In the main group, sutures were removed after 13 days, in the control group - after 8 days. Incidence of postoperative wound infection was 3.2% in the main group and 14.5% in the control group. Long-term postoperative recurrence occurred in 1 patient of the main group and 6 patients of the control group.Limberg flap reconstruction is followed by fewer postoperative complications and recurrences. However, period of rehabilitation and wound healing is longer compared to traditional technique.Эпителиальный копчиковый ход (ЭКХ) — это гнойно-воспалительное заболевание мягких тканей межъягодичной области, при котором образуется свищевой ход, распространяющийся от кожи до пресакральной фасции. Существует множество консервативных и хирургических методов лечения этого заболевания, однако оптимальный до сих пор не найден. Одним из способов является иссечение ЭКХ с пластикой по Лимбергу.Сравнение эффективности двух хирургических техник.В отделении колопроктологии МКНЦ им. А.С. Логинова пролечены 117 пациентов с рецидивным ЭКХ: 62 больным (основная группа) выполнено вмешательство с пластикой по Лимбергу, 55 (контрольная группа) — по традиционной методике с простым ушиванием раны. Данные пролеченных пациентов проанализированы с использованием программного обеспечения SPSS.Средняя продолжительность пребывания в стационаре в основной группе составила 8,2 дня, в контрольной — 5,4 дня. Выраженность болевого синдрома в 1-е сутки после операции различалась — в основной группе он был более выражен, на 3-и сутки различия были незначимыми. Швы в основной группе удалены в среднем на 13-е сутки после операции, в контрольной — на 8-е сутки. В основной группе частота нагноения послеоперационной раны составила 3,2%, в контрольной — 14,5%. В отдаленные сроки зафиксированы случаи рецидива заболевания: в основной группе у 1 пациента, в контрольной — у 6.

Russian society for simulation education in medicine, ROSOMED in cooperation with the Russian society of surgeons and the Russian society of endoscopic surgeons has created the course of Basic Endosurgical Simulation Training and Assessment, BESTA. The present study has established expert, constructive and discriminative validity of the BESTA course.

We studied the effect of ion bombardment on the structure of SOG (spin-on-glass) films. We used IR and Raman spectroscopy and plan-view transmission electron microscopy to study the characteristic features of the structural transformation in organosilicon films when bombarded by nitrogen ions. We show that they are heterogeneous and we establish the presence of inclusions of nanocrystalline graphite.

We report femtosecond photon echo and four-wave mixing measurements performed on GaAs/AlGaAs heterostructure at room temperature. In femtosecond photon echo experiment the dephasing time was obtained, found to vary between 40 and 55 fs depending on carrier density. The dependence showed a power-law behavior T2 ∝ N-0.22, which indicates that major phase coherence loss is due to screened Coulomb electron-electron interaction. Transient grating experiments yielded the electron diffusion coefficient value of 200 cm2/s and electron relaxation time equal to 3 ns.

We report transient refractive index change in semiconductor nanoparticles dispersed in polymethylmethacrylate matrix via pump-probe experiment. At lower pump intensities the detected signal consists of the pulse autocorrelation-shaped part and another part delayed by 300 fs. The latter’s relative intensity depends on the pump level. However in CdS monocrystal the detected signal was found to lack this second feature completely.

We report the non-resonant excitation and probing of the nonlinear refractive index change in bulk semiconductors and semiconductor quantum dots through degenerate transient lens spectroscopy. The signal oscillates at the center laser field frequency, and the envelope of the former in quantum dots is distinctly different from the one in bulk sample. We discuss the applicability of this technique for polarization state probing in semiconductor media with femtosecond temporal resolution.

The results of investigation of optical constant changes for films of polymethylmethacrylate, polystyrene, some of polyimides and industrial positive photoresists irradiated with light ions are presented. It was shown that ion implantation is effective method for modification of optical properties for polymers and that the approach based on molecular refraction changes for chemical bonds permits to forecast the values of refractive indices depending on irradiation doses.

The results of the femtosecond four-wave mixing measurements performed on the CdS crystal at room temperature are reported. The dephasing time Td = 180 fs was obtained. The anti-Stokes shift of the primary photon echo spectrum with respect to the excitation spectrum was observed. The some peculiarities of the coherent responses decay curves indicate that this optical dephasing is due to the exciton-exciton interaction. The stimulated photon echo decay curves appear to have a fast decay component (the time constant of approximately 4.5 ps) in case the energy of exciting pulses exceeds the threshold value of 0.4 μJ.

The present paper deals with the results of a structure and composition study of some ion-implanted polymers: polyimide (PI). poly-p-chlorostyrene, polymethacriloylchloride as well as some organic photoresists. The structures under investigation were irradiated with B+, Ar+ and Sb+ ions at a dose range of 1013 to 1017 ions cm 2 and energies of 40 to 150 keV. The parameters of spatial distribution, elastic and inelastic energy losses were evaluated by Monte Carlo simulation with allowance for recoil atom motion. The principal pattern of structure and composition changes occurring in the above-given polymers were studied by IR spectroscopy and RBS measurements.