Laser Polarimeter for Measurement of Optical Activity of Biological Objects

AbstractIn this paper has been described the polarimetric device for measurement of optical activity of biological tissues, where the source of radiation is an infrared laser with a wave λ=0.808 micron. The polarizers used are polarizing prisms of Glan – Taylor. To obtain required angular resolution (0.180/cm) has been developed a device that converts the angle of rotation of the analyzer into electrical signal, which is fed to the appropriate scan digital oscilloscope. The passage of the polarized light through the fingers of the hand was established and the angles of rotation of the polarization vector of the transmitted radiation were measured, the values of which may be determined by the content of hemoglobin in the blood

Magnetic Resonance Cardiorhythmography as a Method of Study of Human's Cardiovascular System Condition

AbstractIn this article a highly sensitive method for graphic recording of cardiogram by detecting the signal of nuclear magnetic resonance (NMR) of human finger has been developed and signals directly related to movement of blood ejected by the heart into the vessels have been studied. Changes in the behavior of signals depending on the condition of the cardiovascular system of person have been discovered

Time-resolved Visualization of Laser Beam Melting of Silica Glass Powder

AbstractSilica glass is an inorganic dielectric material that can be used for laser beam melting without cracking. However, the extremely high viscosity makes consolidation of powder very slow. To study the dynamics of consolidation, a 10.6μm laser beam was directed on the powder layer deposited on the solid substrate of the same material. The laser-interaction zone was lighted with green laser and filmed with a high-speed camera at 6000 fps. The process develops steadily. Neither fluctuation nor droplets are observed. An expanding consolidation zone is observed. Viscous merging of softened powder particles is supposed to be the principal mechanism of consolidation. Mathematical model based on this mechanism confirms formation of the consolidated zone in the center. Both the experiment and the model indicate that consolidation looks like propagation of a sharp front. Comparison of the experiments and the calculations estimates the consolidation front temperature of about 1800-1900K

Experimental Study of Residual Stresses in Metal Parts Obtained by Selective Laser Melting

AbstractHigh local temperature gradients occur at additive manufacturing by selective laser melting of powder. This gives rise to undesirable residual stresses, deformations, and cracks. To understand how to control the formation of the residual stresses, a reliable method is necessary for measuring their distribution in the fabricated part. It is proposed to cut the part into thin plates and to reconstruct the residual stresses from the measured deformation of the plates. This method is tested on beams with square cross-section built from stainless steel. The beams were cut by electrical discharge machining and chemically etched. The obtained stress profile in vertical transversal direction slightly increases from the top to the bottom of the beam. This dependency is confirmed by numerical modeling. The measured stress profile agrees with the known results by other authors

Бесфиксационная герниопластика при грыжах передней брюшной стенки

Authors has developed algorithm of surgical treatment of the abdominal wall hernias, based on using the modern non-fixation mesh. This algorithm includes different surgical approaches (open and endoscopic) for inguinal and ventral hernias using polypropylene and polylactic acid mesh.В статье определено место бесфиксационных методик в лечении грыж передней брюшной стенки. Разработана целостная система оперативного лечения больных с грыжами передней брюшной стенки, на основе использования современных, не требующих фиксации имплантатов, которая может быть рекомендована к широкому внедрению

ВЫБОР ИМПЛАНТА ДЛЯ ГЕРНИОПЛАСТИКИ ВЕНТРАЛЬНЫХ ГРЫЖ

According to the literature, up to 50% of laparotomies end with herniation. Therefore, postoperative ventral hernias will not lose their relevance for a long time. The appearance of non-tension hernioplasty by means with synthetic implants helped to solve some issues of hernia: the frequency of relapses in the late postoperative period significantly decreased. However, the number of the complications associated with suppuration of postoperative wounds and seroma in the early postoperative period increased. This leads in the increase of number days of hospital treatment, the need for antibiotic therapy, and accordingly the cost of treatment. In this regard, new types of implants that have the necessary biocompatibility properties are constantly being developed. Also, implants with the possibility of self-griping to the tissues have become more and more relevant in recent years. Self-gripping implants are not only convenient for the operating surgeon - reducing the time of operation, but also don’t cause of the chronic pain in the area of operation. However, the problem of surgical treatment of postoperative ventral hernias remains unresolved. The aim of study was to improve the quality of life of patients with postoperative ventral hernias. Was surgery with implants ProgripTM 65 patients. Patients were divided into two groups, taking into account the use of standard implant shape and simulated. The frequencies of surgical complications, duration of surgery and inpatient treatment were compared. The relapse developed in 14.7% and 3.2% of cases, respectively. There were no other significant complications. Conclusion: the simulated implant is anatomically correct and reduces the risk of detachment of the implant from the tissue during stretching.По данным литературы, до 50% лапаротомий заканчиваются образованием грыжи. Поэтому послеоперационные вентральные грыжи еще долго не потеряют своей актуальности. Появление ненатяжной герниопластики с помощью синтетических имплантов помогло решить некоторые вопросы герниологии: значительно уменьшилась частота рецидивов в поздний послеоперационный период. Однако количество осложнений, связанных с нагноением послеоперационных ран и сером, в ранний послеоперационный период увеличилось. Это приводит к увеличению количества дней стационарного лечения, необходимости применения антибактериальной терапии, а соответственно и увеличению стоимости лечения. В связи с этим постоянно разрабатываются новые виды имплантов, которые обладают необходимыми свойствами биосовместимости. Также в последнее время все более актуальными становятся импланты с возможностью самофиксирования к тканям. Самофиксирующиеся импланты не только удобны для оперирующего хирурга - сокращая время оперативного вмешательства, но и не вызывают хронический болевой синдром в зоне операции. Однако проблема хирургического лечения послеоперационных вентральных грыж остается нерешенной. Целью исследования являлось улучшение качества жизни пациентов с послеоперационными вентральными грыжами. Были проведены оперативные вмешательства с использованием импланта ProgripTM 65 пациентам. Пациенты были разделены на две группы с учетом использования импланта стандартной формы и смоделированного. Проведено сравнение частоты хирургических осложнений, длительности операции и стационарного лечения. Рецидив развился соответственно в 14,7% и 3,2% случаях. Других существенно значимых осложнений не было. Вывод: смоделированный имплант является анатомически правильным и уменьшает риск отрыва импланта от тканей при растяжении

The reflection of very cold neutrons from diamond powder nanoparticles

We study possibility of efficient reflection of very cold neutrons (VCN) from powders of nanoparticles. In particular, we measured the scattering of VCN at a powder of diamond nanoparticles as a function of powder sample thickness, neutron velocity and scattering angle. We observed extremely intense scattering of VCN even off thin powder samples. This agrees qualitatively with the model of independent nanoparticles at rest. We show that this intense scattering would allow us to use nanoparticle powders very efficiently as the very first reflectors for neutrons with energies within a complete VCN range up to $10^{-4}$ eV

A method to measure the resonance transitions between the gravitationally bound quantum states of neutrons in the GRANIT spectrometer

We present a method to measure the resonance transitions between the gravitationally bound quantum states of neutrons in the GRANIT spectrometer. The purpose of GRANIT is to improve the accuracy of measurement of the quantum states parameters by several orders of magnitude, taking advantage of long storage of Ultracold neutrons at specula trajectories. The transitions could be excited using a periodic spatial variation of a magnetic field gradient. If the frequency of such a perturbation (in the frame of a moving neutron) coincides with a resonance frequency defined by the energy difference of two quantum states, the transition probability will sharply increase. The GRANIT experiment is motivated by searches for short-range interactions (in particular spin-dependent interactions), by studying the interaction of a quantum system with a gravitational field, by searches for extensions of the Standard model, by the unique possibility to check the equivalence principle for an object in a quantum state and by studying various quantum optics phenomena