Solitonic-exchange mechanism of surface~diffusion

We study surface diffusion in the framework of a generalized Frenkel-Kontorova model with a nonconvex transverse degree of freedom. The model describes a lattice of atoms with a given concentration interacting by Morse-type forces, the lattice being subjected to a two-dimensional substrate potential which is periodic in one direction and nonconvex (Morse) in the transverse direction. The results are used to describe the complicated exchange-mediated diffusion mechanism recently observed in MD simulations [J.E. Black and Zeng-Ju Tian, Phys. Rev. Lett. {\bf 71}, 2445-2448(1993)].Comment: 22 Revtex pages, 9 figures to appear in Phys. Rev.

Master equation approach to the conjugate pairing rule of Lyapunov spectra for many-particle thermostatted systems

The master equation approach to Lyapunov spectra for many-particle systems is applied to non-equilibrium thermostatted systems to discuss the conjugate pairing rule. We consider iso-kinetic thermostatted systems with a shear flow sustained by an external restriction, in which particle interactions are expressed as a Gaussian white randomness. Positive Lyapunov exponents are calculated by using the Fokker-Planck equation to describe the tangent vector dynamics. We introduce another Fokker-Planck equation to describe the time-reversed tangent vector dynamics, which allows us to calculate the negative Lyapunov exponents. Using the Lyapunov exponents provided by these two Fokker-Planck equations we show the conjugate pairing rule is satisfied for thermostatted systems with a shear flow in the thermodynamic limit. We also give an explicit form to connect the Lyapunov exponents with the time-correlation of the interaction matrix in a thermostatted system with a color field.Comment: 10 page

The angiosome concept in revascularization of the shin and foot arteries in patients with diabetes mellitus

Objective. To analyze the results of revascularization of the shin and foot arteries in patients with diabetes mellitus in accordance to the angiosome concept. Materials and methods. Results of roentgen-endovascular interventions on 71 lower extremities, performed in 48 patients, suffering diabetes mellitus and ischemia, menaced for the extremity loss, were analyzed. All the patients had purulent-necrotic affections of the foot Degree III-IV in accordance to classification of WIFI (Wound, Ishemia and Foot Infection). In accordance to anatomic zones of revascularization all roentgen-endovascular interventions were divided into three groups: Group I - 24 (33.8%) direct angiosomic revascularizations, Group II - 38 (53.5%) indirect angiosomic revascularizations, Group III - 9 (12.7%) nonangiosomic revascularizations. Results. There was established, that following the angiosome concept raises possibility of preservation of the lower extremity (92.9%) comparing with nonangiosomic revascularization (77.8%). Conclusion. Efficacy of revascularization of the shin arteries with occlusion-stenotic lesions is significantly higher while restoration of the blood flow in accordance to the angiosome concept

The angiosome concept in revascularization of the shin and foot arteries in patients with diabetes mellitus

Мета: проаналізувати результати реваскуляризації артерій гомілки та стопи у хворих із цукровим діабетом згідно з ангіосомною концепцією. Матеріали і методи. Проаналізовано результати рентгенендоваскулярних втручань на 71 нижній кінцівці, виконаних у 48 хворих із цукровим діабетом та ішемією, що загрожувала втратою кінцівки. Усі пацієнти мали гнійно–некротичні ураження стопи III–IV ступеня за класифікацією WIFI (Wound, Ishemia and Foot Infection). Згідно з анатомічними зонами реваскуляризації всі рентгенендоваскулярні втручання розподілені на три групи: 1–ша група – 24 (33,8%) прямих ангіосомних реваскуляризацій, 2–га група – 38 (53,5%) непрямих ангіосомних реваскуляризацій, 3–тя група – 9 (12,7%) неангіосомних реваскуляризацій. Результати. Встановлено, що дотримання ангіосомної концепції підвищує ймовірність збереження нижньої кінцівки (92,9%) порівняно з неангіосомною реваскуляризацією (77,8%). Висновки. Ефективність реваскуляризації гомілкових артерій з оклюзійно–стенотичними ураженнями значно вища у разі відновлення кровотоку згідно з ангіосомною концепцією.Objective. To analyze the results of revascularization of the shin and foot arteries in patients with diabetes mellitus in accordance to the angiosome concept. Маterials and methods. Results of roentgen–endovascular interventions on 71 lower extremities, performed in 48 patients, suffering diabetes mellitus and ischemia, menaced for the extremity loss, were analyzed. All the patients had purulent–necrotic affections of the foot Degree III–IV in accordance to classification of WIFI (Wound, Ishemia and Foot Infection). In accordance to anatomic zones of revascularization all roentgen–endovascular interventions were divided into three groups: Group I – 24 (33.8%) direct angiosomic revascularizations, Group II – 38 (53.5%) indirect angiosomic revascularizations, Group III – 9 (12.7%) nonangiosomic revascularizations. Results. There was established, that following the angiosome concept raises possibility of preservation of the lower extremity (92.9%) comparing with nonangiosomic revascularization (77.8%). Conclusion. Еfficacy of revascularization of the shin arteries with occlusion–stenotic lesions is significantly higher while restoration of the blood flow in accordance to the angiosome concept

SOME ASPECTS OF SCANNING LASER OPHTHALMOSCOPY IN THE DIAGNOSTICS OF OPHTHALMOPATHOLOGY

The exact diagnosis of the fundus pathology requires the most modern equipment use. This is mandatory for the selection of the most complete therapy and monitoring of ongoing treatment. At present, the method of scanning laser ophthalmoscopy is widely spread. However, for the earliest detection of the smallest pathological changes, data of the normal ocular fundus state using a scanning laser ophthalmoscope is necessary. Thus, the purpose of our research becomes relevant. Purpose: to give a characteristic of the fundus in patients without concomitant pathology with using various modes of a scanning laser ophthalmoscope. Patients and methods. 116 people (232 eyes) at the age from 17 to 71 years (mean age 32.5±12 years) were examined. The patients were divided into two groups. Group I: 81 patients (162 eyes) with different ophthalmopathology. Group II: 35 people (70 eyes) — practically healthy and did not have an anamnesis of consulting an ophthalmologist. Diagnosis of the patients’ fundus was performed using a scanning laser ophthalmoscopy with retro-mode imaging and autofluorescence registration. Results. After the conducted research features and regularities of the reflectivity distribution of laser beams from the fundus structures are revealed. Also a characteristic of various anatomical formations and zones of the fundus in the normal conditions is given when examined by a scanning laser ophthalmoscope. An algorithm for examining patients and analyzing the images was developed. Conclusion. The use of scanning laser ophthalmoscopy made possible to take a fresh look at the algorithms of diagnosing patients with fundus pathology. Understanding the normal conditions ofundus allowed an earlier detection of the smallest pathological changes in the retina