Biophysics and medical physics

Study of Statistical Characteristics of GB-speckles, Forming at Scattering of Light on Virtual Structures of Nucleotide Gene Sequences of Enterobacteria

Background and Objectives: A brief review of methods of modern bioinformatics, based on the usage of virtual optical GBspeckles (gene-based speckles), has been presented in this paper. An algorithm of transformation of a nucleotide sequence into a 2D GB-speckle-structure has been proposed and discussed.

Estimation of Glucose Diffusion Coefficient in Human Dura Mater

Background and Objectives: Optical clearing of dura mater caused by hyperosmotic immersion liquids is important for the development of noninvasive methods of brain optical tomography and for the study of microcirculation and homeostasis of tissue fluids. It allows significantly increasing the spatial resolution and the probing depth of brain. Obviously, a quantitative description of the optical clearing processes requires the development of reliable physicomathematical models, which in turn requires the knowledge of the diffusion rate parameters of immersion agents in tissues.

Optical Doppler Methods for the Measurements of Flow Velocities of Biological Liquids

Background and Objectives: In this paper the key results obtained by the authors during the years of development of Doppler optical methods for quasi-elastic light scattering and coherence gating on biomedical liquids are presented. The research is focused on the sign sensitive velocity measurement and quantitative visualization of alternating and complex geometry flows using spectral approach to digital data processing of Doppler shift of the carrier frequency.

HETEROPHASE SEMICONDUCTORS UNDERACTION OF IRRADIATIONS

The history and current state of our heteropfiase photoconducting CdS-PbS films investigations are observed. Films were prepared by the vacuum evaporation method from the materials with limited mu tual solubility. Reasons of increased degradation stability with respect to radiation (in particular y- and electronic irradiations) are found out. Degradation stability is explained by diversion of recombination flow from wide-gap phase to narrow-gap. Radiation stimulated defects also move to narrow-gap phase.

НЕСТАЦИОНАРНОЕ ВОЗБУЖДЕНИЕ ОТКРЫТЫХ СТРУКТУР

Получены нестационарные электродинамические уравнения возбуждения открытых резонаторов и волноводных трансформаторов, основанные на методе функций Грина. Для открытого резонатора получены также аналогичные формулы, основанные на спектральном подходе. В общем виде задача о возбуждении сводится к интегральным уравнениям в пространственновременной области.

ГЕНЕРАТОР АНИЩЕНКО-АСТАХОВА КАК ОДНА ИЗ БАЗОВЫХ МОДЕЛЕЙ ДЕТЕРМИНИРОВАННОГО ХАОСА

В обзоре формулируются условия возникновения хаотических автоколебаний и дается радиотехническая схема генератора, которая эти условия реализует. Выводятся уравнения генератора Анищенко-Астахова и проводится их анализ. Особое внимание уделяется взаимосвязи уравнений генератора с классическими моделями Теодорчика и Ван дер Поля.

Leukocytes’ «Highlighting» Effect and its Application to Identify Blood Cells by Digital Microscopy Method

Objective: To find a way of identifying and counting of leukocytes in a native blood sample. Materials and equipments: Whole donor blood sample, digital microscop. Methods and approaches: The development of a method of leukocytes’ identification and counting for native blood samples was carried out on the basis of digital microscopy method. Main results: Leukocytes’ “highlighting” effect in a native blood sample was revealed experimentally by digital microscope examining.

Albumin Conformational Changes During Glycation and Thermal Denaturation Processes Revealed by Fluorescence Spectroscopy and Small-angle X-ray Scattering

Background and Objectives: Objects of the research in this study are solutions of bovine serum albumin (BSA) and its aggregates. Structural changes of the protein molecules in solution with pH 3 and pH 7.4 are investigated during glycation and thermal denaturation processes, when the BSA molecules in solution undergo similar intermediate states. The main aim of the research is to compare structural changes of the BSA upon its glycation and thermal denaturation, revealed by combination of optical and X-ray techniques.

Investigation of the Interaction and Dynamics of Collagen and Collagenase Molecules in Solutions by Dynamic Light Scattering

Background and Objectives: Bacterial collagenase from Closrtidium histolyticum is widely used as a clinical tool in the nonsurgical treatment of Dupuytren’s disease in eye’s disorders treatment, for enzymatic debridement, for accelerated resorption of catgut sutures. Collagenase main feature is its ability to digest key protein of the animal extracellular matrix – collagen. Dynamic Light Scattering (DLS) technique allows for investigation of collagen and collagenase solutions in conditions close to physiological.

Monte Carlo Simulation of Laser Radiation Propagation in the Multilayers Model of Head and Brain Tissues in Health and in the Presence of Intracranial Hematoma

Background and Objectives: Development of new optical methods of non-contact express diagnostics of intracranial hematoma remains an actual task. The development of optical model of the head in norm and in the presence of intracranial hematoma is the aim of the present study. Influence of the dimensions of the head tissues with and without hematoma on distribution of the backscattered laser radiation intensity is discussed. Materials and Methods: The optical model of the head and brain tissues in norm and in the presence of intracranial hematoma is developed.

Pages