Динамика некоторых биофизических параметров кожи человека в процессе оптического просветления при воздействии гиперосмотических агентов

Goal of the study. To study changes of certain biophysical parameters of human skin in the process of optical (immersion) clarification under the effect of hyperosmotic agents. Materials and methods. Measurements were made on the skin (on the right and left hands) of 18 female volunteers aged 17-38. Biophysical parameters of the skin and its phototype were determined with the use of Soft Plus, a device for the diagnostics of the skin condition (Callegari, Italy), and erythema melanin meter (EMM-002E, Russia). 30%, 40% and 50% aqueous glucose solutions as well as 50% aqueous-alcoholic (30°) fructose solution were used as hyperosmotic (dehydrating) study agents. Results. It was revealed that the extent and time of skin dehydration mostly depend on the method of application of the immersion agent and its composition. Depending on the applied technology, it is possible to achieve both a decrease and an increase in the skin moisture extent, which is related to the physiological response of the skin to the occlusion and osmotic action of the agents. 50% aqueous-alcoholic fructose solution appears to be the most efficient dehydrating agent of all study agents.Цель работы. Изучить динамику некоторых биофизических параметров кожи человека в процессе оптического (иммерсионного) просветления при воздействии гиперосмотических агентов. Материал и методы. Измерения проводились на коже (на правой и левой руке) 18 добровольцев женского пола, возраст которых составлял от 17 до 38 лет. Определение биофизических параметров кожи и ее фототипа проводилось с помощью аппарата для диагностики состояния кожи Soft Plus (Callegari, Италия) эритема-меланинометра (ЭММ-002Е, Россия). В качестве исследуемых гиперосмотических (дегидратирующих) агентов использовались водные растворы глюкозы с концентрацией 30, 40 и 50%, а также 50% водно-спиртовой (30°) раствор фруктозы. Результаты. Показано, что степень и время дегидратации кожи существенно определяются способом аппликации иммерсионного агента и его составом. В зависимости от применяемой технологии можно получить как уменьшение, так и увеличение степени увлажнения кожи, что связано с физиологическим ответом кожи на окклюзию и осмотическое действие препаратов. Наиболее эффективным дегидратирующим агентом из исследованных является 50% водно-спиртовой раствор фруктозы

Адресная доставка фотосенсибилизатора для фотохимиотерапии витилиго

Aim. In this work, the authors set out to develop an effective method for the intrafollicular delivery of “Ammi majus fructuum furocumarines” photosensitizer (AMFF) followed by UVA irradiation (λ = 320–400 nm). Materials and methods. The proposed delivery method consists in using calcium carbonate particles acting as AMFF carriers. In vivo monitoring of hair follicle filling was carried out via optical coherence tomography, as well as by means of analyzing epilated hair using confocal laser scanning microscopy. Following the administration of free and encapsulated AMFF to three healthy volunteers, the character of UVA-induced skin pigmentation was registered under dermatoscopic examination. Results. The obtained results demonstrate a profuse filling of hair follicles with calcium carbonate particles, thus confirming the possibility of intrafollicular photosensitizer delivery. It was established that exposure to UVA irradiation causes intense pigment accumulation in the area of AMFF carrier administration. Conclusion. The proposed method of the targeted photosensitizer delivery allows photochemical therapy to be improved.Цель: разработка эффективного способа доставки фотосенсибилизатора Ammi majus fructuum furocumarines (AMFF) в волосяные фолликулы с последующим применением УФА-облучения (λ = 320–400 нм). Материалы и методы. Предлагаемый способ доставки заключается в применении частиц карбоната кальция, выступающих в роли контейнера-носителя AMFF. Исследование заполнения волосяных фолликулов было проведено in vivo методом оптической когерентной томографии, а также путем экстракции волос с последующим исследованием методом лазерной конфокальной флуоресцентной микроскопии. Регистрация характера пигментации кожи 3 здоровых добровольцев после сеанса УФА-облучения участков с предварительным внедрением препарата AMFF в свободном и иммобилизованном виде была осуществлена методом дерматоскопии. Результаты. Продемонстрировано обильное заполнение волосяных фолликулов частицами карбоната кальция, доказана возможность интрафолликулярной доставки фотосенсибилизатора с их помощью. Установлено, что в результате УФА-облучения в месте внедрения контейнеров, нагруженных AMFF, происходит значительное накопление пигмента. Заключение. Предложенный способ адресной доставки фотосенсибилизатора позволяет оптимизировать методику фотохимиотерапевтического воздействия

Dynamics of the brain: Mathematical models and non-invasive experimental studies

Dynamics is an essential aspect of the brain function. In this article we review theoretical models of neural and haemodynamic processes in the human brain and experimental non-invasive techniques developed to study brain functions and to measure dynamic characteristics, such as neurodynamics, neurovascular coupling, haemodynamic changes due to brain activity and autoregulation, and cerebral metabolic rate of oxygen. We focus on emerging theoretical biophysical models and experimental functional neuroimaging results, obtained mostly by functional magnetic resonance imaging (fMRI) and near-infrared spectroscopy (NIRS). We also included our current results on the effects of blood pressure variations on cerebral haemodynamics and simultaneous measurements of fast processes in the brain by near-infrared spectroscopy and a very novel functional MRI technique called magnetic resonance encephalography. Based on a rapid progress in theoretical and experimental techniques and due to the growing computational capacities and combined use of rapidly improving and emerging neuroimaging techniques we anticipate during next decade great achievements in the overall knowledge of the human brain

Spectroscopic study of demineralization and restoration processes in dental enamel

Progress in Biomedical Optics and Imaging - Proceedings of SPIE6628

Simulation and modeling of optical phase contrast microscope cellular nanobioimaging

We apply a previously developed 3D Finite-Difference Time-Domain (FDTD) simulation method to model the optical phase contrast microscopic (OPCM) visualization of Gold nanoparticles (NPs) attached to the nucleus of a singe biological cell. We consider a realistic size 3D cell model at optical immersion conditions, i.e. when the refractive index values of the cytoplasm and of the extra-cellular medium are equal. The visual effect of the Gold NPs is studied at both resonant and non-resonant conditions. The results show that, at resonance, there are specific visual patterns that could be used for the identification of the presence of NPs at the nucleus' surface. The model demonstrates the capability to model the specific conditions of OPCM image enhancement by optically controlling the resonant properties of the NPs

Cell membrane and gold nanoparticles effects on optical immersion experiments with noncancerous and cancerous cells: finite-difference time-domain modeling.

Pilot results on the application of the finite-difference time-domain (FDTD) approach for studying the implementation of the optical immersion technique for the visualization of single and multiple gold nanoparticles in biological cells are presented. We focus on two different scenarios considering single biological cells containing (1) cytoplasm, nucleus, and membrane and (2) cytoplasm, nucleus, gold nanoparticles, and membrane. To the best of our knowledge, this is the first time the cell membrane thickness and gold nanoparticle effects on the forward scattered light from biological cells are discussed. The applicability and the potential of the FDTD approach for studying optical immersion technique enhanced bioimaging is demonstrated

Light scattering effects of gold nanoparticles in cells: FDTD modeling

The FDTD modeling approach is applied to study the implementation of the optical immersion technique for the visualization of single and multiple gold nanoparticles in biological cells. To the best knowledge of authors, this is the first research study discussing the gold nanoparticle effects on the forward scattered light from biological cells at refractive index matching conditions. The applicability and the potential of the FDTD approach for studying gold nanoparticles enhanced bio-imaging at optical immersion is demonstrated. A graph is Presented

Signal to noise ratio in balanced OCT under wide band illumination

In optical coherence tomography (OCT), it is often assumed that the signal-to-noise ratio is limited by shot noise. However, a high data acquisition rate and a low target reflectivity require operation under high optical power. Balance detection is used with the aim to bring the noise close to shot noise regime, but this is not all the time achievable in practice. If the balance detection is ideal, the limiting factor is the beat noise. This is proportional to the stray reflectance in the object arm and inverse proportional to the effective noise bandwidth. It was often noticed that the limiting theoretical value for the S/N ratio for a given stray reflectance and optical source bandwidth could not be experimentally achieved. In the present study we develop a new model where we address this issue by taking into account the limited spectral response of fiber based balanced detection receivers. We show that due to mismatches in the balanced receiver, excess photon noise has a larger contribution than normally expected, with important implications in the maximum achievable SNR. The theoretical model developed leads to a redefinition of the effective noise bandwidth to take into account the non-flat response of the directional coupler used in the balanced stage. The model is capable to explain the limitation of SNR observed in practice when stray reflectances within the interferometer are brought to infinitesimal values. The model guides optimization of parameters in order to maximize system performance, for a given optical source power and directional coupler characteristics. In this paper we present experimental results to validate the theoretical model. Such S/N analysis is paramount in the modern OCT technology, which makes use of wide bandwidth sources in the quest for high-depth resolution

ОСТ investigation of influence of cement kiln dust and keratoprotectoral medication on the cornea structure.

The research goal: in vitro study of cornea permeability at the action of cement kiln dust and keratoprotectoral medication. Materials and Methods. Experimental studies were carried out with twenty eyes often rabbits. The measurements were performed using ОСТ system OCP930SR 022 (Thorlabs, USA). Results. ОСТ tomography was used to monitor the attenuation coefficient of the cornea in vitro during the permeability of cement kiln dust and keratoprotector Systein Ultra. The permeability coefficients of the cornea for water, cement dust and keratoprotector were measured. A computer model was developed that allowed one to analyze the diffusion of these substances in the eye cornea. Conclusion. It is shown: 1) cement dust falling on the eye cornea caused pronounced dehydration of the tissue (thickness decreasing) and led to the increase in the coefficient of light attenuation, which in the conditions of cement production could affect the deterioration of the eyesight of workers; 2) the application of the keratoprotector on the eye cornea when exposed by cement dust, slowed significantly the dehydration process and did not cause the increase in the light attenuation coefficient, which characterized the stabilization of visual functions in cement production workers. In this case, the keratoprotector itself did not cause dehydration and led to the decrease in the light attenuation coefficient, which could allow it to be used for a long time in the order to protect the organ of vision from the negative effects of cement dust.</p