Experimental Appropriateness Verification of K. Gorodetsky`s Mathematical Model for Losses Determinination in Hydrostatic Transmissions for Modern Hydrolic Machines

There were experimentally obtained dependences of efficiency coefficients for two hydrostatic transmissions of various sizes and performance on the basis of axial-piston hydraulic machines under various loading conditions. The experimental data is compared with the calculated one obtained using the mathematical model of K. Gorodetsky. The object of study was the hydrostatic monoblock transmission manufactured in 1999 and the hydrostatic transmission made in 2012 with a spaced hydraulic pump and hydraulic motor

Influence of nanotube length and density on the plasmonic terahertz response of single-walled carbon nanotubes

We measure the conductivity spectra of thin films comprising bundled single-walled carbon nanotubes (CNTs) of different average lengths in the frequency range 0.3-1000 THz and temperature interval 10-530 K. The observed temperature-induced changes in the terahertz conductivity spectra are shown to depend strongly on the average CNT length, with a conductivity around 1 THz that increases/decreases as the temperature increases for short/long tubes. This behaviour originates from the temperature dependence of the electron scattering rate, which we obtain from Drude fits of the measured conductivity in the range 0.3-2 THz for 10 $\mu$m length CNTs. This increasing scattering rate with temperature results in a subsequent broadening of the observed THz conductivity peak at higher temperatures and a shift to lower frequencies for increasing CNT length. Finally, we show that the change in conductivity with temperature depends not only on tube length, but also varies with tube density. We record the effective conductivities of composite films comprising mixtures of WS$_2$ nanotubes and CNTs vs CNT density for frequencies in the range 0.3-1 THz, finding that the conductivity increases/decreases for low/high density films as the temperature increases. This effect arises due to the density dependence of the effective length of conducting pathways in the composite films, which again leads to a shift and temperature dependent broadening of the THz conductivity peak.Comment: Submitted to Journal of Physics D. Main manuscript: 9 pages, 8 figures. Supplementary material: 5 pages, 6 figure

TTX-sensitive Na+ and nifedipine-sensitive Ca2+ channels in rat vas deferens smooth muscle cells

The inward currents in single smooth muscle cells (SMC) isolated from epididymal part of rat vas deferens have been studied using whole-cell patch-clamp method. Depolarising steps from holding potential -90 mV evoked inward current with fast and slow components. the component with slow activation possessed voltage-dependent and pharmacological properties characteristic for Ca2+ current carried through L-type calcium channels (I-Ca). the fast component of inward current was activated at around -40 mV, reached its peak at 0 mV, and disappeared upon removal of Na ions from bath solution. This current was blocked in dose-dependent manner by tetrodotoxin (TTX) with an apparent dissociation constant of 6.7 nM. On the basis of voltage-dependent characteristics, TTX sensitivity of fast component of inward current and its disappearance in Na-free solution it is suggested that this current is TTX-sensitive depolarisation activated sodium current (I-Na) Cell dialysis with a pipette solution containing no macroergic compounds resulted in significant inhibition of I-Ca (depression of peak I-Ca by about 81% was observed by 13 min of dialysis), while I-Na remained unaffected during 50 min of dialysis. These data draw first evidence for the existence of TTX-sensitive Na+ current in single SMC isolated from rat vas deferens. These Na+ channels do not appear to be regulated by a phosphorylation process under resting conditions. (C) 1999 Elsevier Science B.V. All rights reserved.Natl Acad Sci Ukraine, Bogomoletz Inst Physiol, Nerve Muscle Physiol Dept, UA-24 Kiev, UkraineUniversidade Federal de São Paulo, Escola Paulista Med, Dept Pharmacol, São Paulo, BrazilUniversidade Federal de São Paulo, Escola Paulista Med, Dept Pharmacol, São Paulo, BrazilWeb of Scienc

Some aspects of teaching medical informatics at medical universities

В статті розглядаються питання сучасного викладання медичної інформатики студентам медичних університетів. В роботі описано основну мету дисципліни, пропонуються шляхи вдосконалення її. Актуальність даної тематики підтверджує те, що наукові методи та інструментальні засоби все більш широко проникають в будь-які галузі життєдіяльності людини, і медицина не є виключенням, Саме це надає медичній інформатиці характер міждисциплінарної галузі, яка набуває все більш важливе загальнонаукове і загальноосвітнє значення. Розкрито важливе питання забезпечення формування у сучасного лікаря цілісного системного наукового світогляду на проблеми інформатизації охорони здоров'я. Дана стаття буде цікава викладачам закладів вищої медичної освіти.The article discusses the issues of up-to-date teaching medical informatics to students of medical universities. The paper describes the main goal of the discipline, suggests ways to improve it. The relevance of this topic lies in the fact that scientific methods and tools are increasingly penetrating into any branch of human life, and medicine is not an exception. That is why Medical Informatics belongs to interdisciplinary field, and acquires important scientific and educational value. Authors disclosed the important issue of the formation of a holistic and scientific worldview in modern doctors on the problems of health care informatization. This article would be interesting to teachers of higher educational institutions of a medical profile

Effect of platelet-rich fibrin matrix in complex with artificial material Nubiplant on expression of chondrogenic marker genes and morphogenesis of the nucleus pulposus cells of intervertebral discs in rats

The purpose was to study the barrier and biological properties of platelet-rich fibrin matrix (PRFM), an artificial biopolymer Nubiplant, and a mixture of PRFM / Nubiplant by assessing the viability and morphological characteristics of nucleus pulposus (NP) cells in rats, as well as the expression level of chondrogenic marker genes during cell cultivation in the presence of these matrices.Materials and methods. PRFM was obtained from platelet-rich plasma using a SiO2 coagulation activator. A suspension of nucleus pulposus cells was obtained from the caudal spine of rats. Cultivation was carried out in the presence of one of three matrices — PRFM, Nubiplant, or their mixture for 3, 7, and 14 days under standard culture conditions in an EC-160 incubator (Nüve, Turkey). Observation of the living culture was carried out in the area bordering with the matrix within one field of view using an inverted microscope (Nicon TS100, Japan). The expression of chondrogenic marker genes in the cell culture of the NP was determined by the method of PCR with reverse transcription.Results. The study of the viability and morphological characteristics of NP cells during their cultivation for 3, 7, and 14 days in the presence of PRFM, PRFM / Nubiplant, or Nubiplant showed a decrease in the content of living cells in control samples; in cultures with PRFM and PRFM / Nubiplant, the number of living cells significantly exceeded the control values, aggregation of cells was observed in the area bordering with the matrices from the side of the application. None of the experimental samples showed the outflow of cells to the opposite side of the matrix after 14 days of cultivation; thus, PRFM, Nubiplant, and their mixture can perform barrier functions to keep the cell population in a certain location. Expression of the COL II, ACAN, GPC3, ANXA3, PTN, MGP, and VIM genes by the NP cells during cultivation for 3 and 7 days in the presence of PRFM and PRFM / Nubiplant increased as compared to the control samples.Conclusions. The use of PRFM, Nubiplant, or a mixture of PRFM / Nubiplant during the cultivation of NP cells demonstrated the absence of cell outflow to the opposite side of the studied matrices during the study period (14 days). The use of PRFM, Nubiplant, or a mixture of PRFM / Nubiplant promoted the formation of cell colonies with chondrocyte-like morphology in the zone bordering with the matrices and maintained cell viability throughout the study period. PRFM and PRFM / Nubiplant contributed to the maintenance of the expression of chondrogenic genes in the NP cells in the zone bordering the matrices. The results obtained indicate the positive effect of the matrix based on platelet-rich fibrin on the NP cells and its barrier functions, which is promising for the use of PRMF for preventing the formation of cicatricial adhesion

Thermal management system for electronic devices

A four-channel thermal management system with low level of electromagnetic interference is proposed. The system is designed for single- and multi-core CPUs, GPUs, motherboard chipsets etc., emitting a heat flow with the density up to 200 W/cm2

Дегенерація міжхребцевих дисків та методи її біологічної корекції

Human physical possibilities limitation caused by intervertebral discs degenerative diseases is a serious medical and social problem in our time. Main signs of intervertebral discs degenerative diseases — cells death, proteoglycane and collagen synthesis decrease. Intervertebral discs degeneration is frequent cause of painful syndrome forming. Today therapy is directed not only on painful syndrome elimination but also on dick’s functions renewing. Modern technologies are frequently based on biological materials using. Injections of proteins activators, biomaterials, different cell types or cell complexes and extracellular matrix, genetically modified cells, and in vitro constructed tissue are used for intravertebral disc regeneration activation. Using one or another therapeutic tactic sufficiently depends on degenerative state expressivity, taking into account the procedure safety.Ограничение физических возможностей человека вследствие дегенеративной болезни межпозвонкового диска является важной медицинской и социальной проблемой современности. Основные признаки дегенеративной болезни межпозвонкового диска — гибель клеток, уменьшение синтеза протеогликана и коллагена. Дегенерация межпозвонкового диска является частой причиной формирования болевого синдрома. В настоящее время терапия направлена не только на устранение болевого синдрома, но и на восстановление функций межпозвонкового диска. Современные технологии часто основаны на использовании биологических материалов. Для активации регенерации межпозвонкового диска используют инъекции белков активаторов, биоматериалов, различных типов клеток или комплексов клеток и экстраклеточного матрикса, генетически модифицированные клетки, in vitro сконструированную ткань. Использование той или иной лечебной тактики в значительной степени зависит от выраженности дегенерации с учетом безопасности процедуры.Обмеження фізичних можливостей людини внаслідок дегенеративної хвороби міжхребцевого диска є важливою медичною й соціальною проблемою нашого часу. Основні ознаки дегенеративної хвороби міжхребцевого диска — загибель клітин, зменшення синтезу протеоглікану та колагену. Дегенерація міжхребцевого диска є частою причиною формування больового синдрому. В наш час терапія спрямована не тільки на усунення больового синдрому, а й на відновлення функцій міжхребцевого диска. Сучасні технології часто основані на використанні біологічних матеріалів. Для активації регенерації міжхребцевого диска використовують ін’єкції білків активаторів, біоматеріалів, різних типів клітин або різних комплексів клітин та різних типів позаклітинного матриксу, генетично модифіковані клітини, in vitro сконструйовану тканину. Вибір тієї або іншої тактики лікування значною мірою визначається ступенем вираженості дегенерації та умовами безпеки проведення процедури

Carbon nanotube sponges as tunable materials for electromagnetic applications

The microwave conductivity and permittivity of both single-walled and multi-walled carbon nanotube (SWCNT and MWCNT) sponges were measured while compressing the samples. Compression leads to a huge variation of the absorptance, reflectance, and transmittance of the samples. The dependence of the microwave conductivity on the sponge density follows a power-law relation with exponents 1.7 ± 0.1 and 2.0 ± 0.2 for MWCNT and SWCNT sponges, respectively. These exponents can be decreased slightly by the addition of a non-conducting component which partly electrically separates adjacent tubes within the samples. The conductivity of MWCNT sponge was measured in the terahertz range while heating in air from 300 to 513 K and it increased due to an increase of a number of conducting channels in MWCNTs