298 research outputs found
Continuous Modeling of Arterial Platelet Thrombus Formation Using a Spatial Adsorption Equation
In this study, we considered a continuous model of platelet thrombus growth in
an arteriole. A special model describing the adhesion of platelets in terms of
their concentration was derived. The applications of the derived model are not
restricted to only describing arterial platelet thrombus formation; the model
can also be applied to other similar adhesion processes. The model reproduces
an auto-wave solution in the one-dimensional case; in the two-dimensional
case, in which the surrounding flow is taken into account, the typical torch-
like thrombus is reproduced. The thrombus shape and the growth velocity are
determined by the model parameters. We demonstrate that the model captures the
main properties of the thrombus growth behavior and provides us a better
understanding of which mechanisms are important in the mechanical nature of
the arterial thrombus growth
Π‘ΠΎΡΠ±Π΅Π½ΡΡ Π΄Π»Ρ ΡΠΊΡΡΡΠ°ΠΊΠΎΡΠΏΠΎΡΠ°Π»ΡΠ½ΠΎΠ³ΠΎ ΡΠ΄Π°Π»Π΅Π½ΠΈΡ ΡΠΎΠΊΡΠΈΡΠ΅ΡΠΊΠΈΡ Π²Π΅ΡΠ΅ΡΡΠ² ΠΈ ΠΌΠΎΠ»Π΅ΠΊΡΠ» Ρ Π½Π΅ΠΆΠ΅Π»Π°ΡΠ΅Π»ΡΠ½ΠΎΠΉ Π±ΠΈΠΎΠ»ΠΎΠ³ΠΈΡΠ΅ΡΠΊΠΎΠΉ Π°ΠΊΡΠΈΠ²Π½ΠΎΡΡΡΡ (ΠΎΠ±Π·ΠΎΡ)
The review devoted to sorbents and sorbentbased medical devices used in clinical practice for extracorporealΒ detoxification using a hemoperfusion technique. Clinical data have confirmed the effectiveness of this approach forΒ removal of bacterial endotoxins, lowdensity lipoproteins, and bilirubin. Other studies demonstrated successfulΒ application of sorbents to treat autoimmune diseases. Special attention is paid to hemoperfusion in as a possibleΒ treatment for severe sepsis and septic shock. The review justifies importance of development and application ofΒ novel multimodal sorbents, which combine both properties of selective and nonselective sorbents. The review discusses clinical efficacy of hemoperfusion and key molecular interactions between the sorbent and circulating molecules pathogenetically relevant to developing critical illness and severe diseases. The reference list: 137.Π ΠΎΠ±Π·ΠΎΡΠ΅ ΡΠ°ΡΡΠΌΠΎΡΡΠ΅Π½Ρ ΡΠΎΡΠ±Π΅Π½ΡΡ ΠΈ ΠΌΠ΅Π΄ΠΈΡΠΈΠ½ΡΠΊΠΈΠ΅ ΠΈΠ·Π΄Π΅Π»ΠΈΡ Π½Π° ΠΈΡ
ΠΎΡΠ½ΠΎΠ²Π΅, ΠΏΡΠΈΠΌΠ΅Π½ΡΠ΅ΠΌΡΠ΅ Π² ΠΊΠ»ΠΈΠ½ΠΈΡΠ΅ΡΠΊΠΎΠΉΒ ΠΏΡΠ°ΠΊΡΠΈΠΊΠ΅ Π΄Π»Ρ ΡΠΊΡΡΡΠ°ΠΊΠΎΡΠΏΠΎΡΠ°Π»ΡΠ½ΠΎΠΉ Π΄Π΅ΡΠΎΠΊΡΠΈΠΊΠ°ΡΠΈΠΈ Ρ ΠΏΠΎΠΌΠΎΡΡΡ ΠΏΡΠΎΡΠ΅Π΄ΡΡΡ Π³Π΅ΠΌΠΎΡΠΎΡΠ±ΡΠΈΠΈ. ΠΡΠ΅Π΄ΡΡΠ°Π²Π»Π΅Π½Ρ Π΄Π°Π½Π½ΡΠ΅ ΠΈΡΡΠ»Π΅Π΄ΠΎΠ²Π°ΡΠ΅Π»Π΅ΠΉ, ΡΠ²ΠΈΠ΄Π΅ΡΠ΅Π»ΡΡΡΠ²ΡΡΡΠΈΠ΅ ΠΎΠ± ΡΡΡΠ΅ΠΊΡΠΈΠ²Π½ΠΎΡΡΠΈ ΡΠ°ΠΊΠΎΠ³ΠΎ ΠΏΠΎΠ΄Ρ
ΠΎΠ΄Π° Ρ ΡΠ΅Π»ΡΡ ΡΠ΄Π°Π»Π΅Π½ΠΈΡ Π±Π°ΠΊΡΠ΅ΡΠΈΠ°Π»ΡΠ½ΡΡ
ΡΠ½Π΄ΠΎΡΠΎΠΊΡΠΈΠ½ΠΎΠ², Π»ΠΈΠΏΠΎΠΏΡΠΎΡΠ΅ΠΈΠ½ΠΎΠ² Π½ΠΈΠ·ΠΊΠΎΠΉ ΠΏΠ»ΠΎΡΠ½ΠΎΡΡΠΈ, Π±ΠΈΠ»ΠΈΡΡΠ±ΠΈΠ½Π°, Π° ΡΠ°ΠΊΠΆΠ΅ ΠΏΡΠΈ Π»Π΅ΡΠ΅Π½ΠΈΠΈ Π°ΡΡΠΎΠΈΠΌΠΌΡΠ½Π½ΡΡ
Π·Π°Π±ΠΎΠ»Π΅Π²Π°Π½ΠΈΠΉ. ΠΡΠ½ΠΎΠ²Π½ΠΎΠ΅ Π²Π½ΠΈΠΌΠ°Π½ΠΈΠ΅ ΡΠ΄Π΅Π»Π΅Π½ΠΎ ΠΏΡΠΈΠΌΠ΅Π½Π΅Π½ΠΈΡ Π³Π΅ΠΌΠΎΡΠΎΡΠ±ΡΠΈΠΈ ΠΏΡΠΈ Π»Π΅ΡΠ΅Π½ΠΈΠΈ ΡΡΠΆΠ΅Π»ΠΎΠ³ΠΎ ΡΠ΅ΠΏΡΠΈΡΠ° ΠΈΒ ΡΠ΅ΠΏΡΠΈΡΠ΅ΡΠΊΠΎΠ³ΠΎ ΡΠΎΠΊΠ°. ΠΠ±ΠΎΡΠ½ΠΎΠ²ΡΠ²Π°Π΅ΡΡΡ Π½Π΅ΠΎΠ±Ρ
ΠΎΠ΄ΠΈΠΌΠΎΡΡΡ ΡΠ°Π·ΡΠ°Π±ΠΎΡΠΊΠΈ ΠΈ ΠΏΡΠΈΠΌΠ΅Π½Π΅Π½ΠΈΡ Π½ΠΎΠ²ΡΡ
Β«ΠΌΡΠ»ΡΡΠΈΠΌΠΎΠ΄Π°Π»ΡΠ½ΡΡ
» ΡΠΎΡΠ±Π΅Π½ΡΠΎΠ², ΡΠΎΡΠ΅ΡΠ°ΡΡΠΈΡ
ΡΠ²ΠΎΠΉΡΡΠ²Π° ΠΊΠ°ΠΊ Β«ΡΠ΅Π»Π΅ΠΊΡΠΈΠ²Π½ΡΡ
Β», ΡΠ°ΠΊ ΠΈ Β«Π½Π΅ΡΠ΅Π»Π΅ΠΊΡΠΈΠ²Π½ΡΡ
Β» ΡΠΎΡΠ±Π΅Π½ΡΠΎΠ². Π ΠΎΠ±Π·ΠΎΡΠ΅ ΠΏΡΠΈΠ²Π΅Π΄Π΅Π½Ρ ΡΠ²Π΅Π΄Π΅Π½ΠΈΡ ΠΎ ΠΊΠ»ΠΈΠ½ΠΈΡΠ΅ΡΠΊΠΎΠΉ ΡΡΡΠ΅ΠΊΡΠΈΠ²Π½ΠΎΡΡΠΈ Π³Π΅ΠΌΠΎΡΠΎΡΠ±ΡΠΈΠΈ ΠΈ ΠΌΠΎΠ»Π΅ΠΊΡΠ»ΡΡΠ½ΠΎΠΌ Π²Π·Π°ΠΈΠΌΠΎΠ΄Π΅ΠΉΡΡΠ²ΠΈΠΈ ΡΠΎΡΠ±Π΅Π½ΡΠ° Ρ ΡΠΈΡΠΊΡΠ»ΠΈΡΡΡΡΠΈΠΌΠΈ ΠΌΠΎΠ»Π΅ΠΊΡΠ»Π°ΠΌΠΈ, ΠΏΠ°ΡΠΎΠ³Π΅Π½Π΅ΡΠΈΡΠ΅ΡΠΊΠΈ Π·Π½Π°ΡΠΈΠΌΡΠΌΠΈ Π΄Π»Ρ ΡΠ°Π·Π²ΠΈΡΠΈΡ ΠΊΡΠΈΡΠΈΡΠ΅ΡΠΊΠΈΡ
ΡΠΎΡΡΠΎΡΠ½ΠΈΠΉ ΠΈ ΡΡΠΆΠ΅Π»ΡΡ
Β Π·Π°Π±ΠΎΠ»Π΅Π²Π°Π½ΠΈΠΉ. ΠΠΈΠ±Π»ΠΈΠΎΠ³ΡΠ°ΡΠΈΡ β 137 ΡΡΡΠ»ΠΎΠΊ
Numerical analysis of the stress-strain state of osteotomies of the first metatarsal bone
Deviation of the first toe to the outside, interconnected with the deviation of the first metatarsal bone to the inside, occurs in 46% of patients of the older age group and is called valgus deformity of the first toe. The negative impact of this pathology on the quality of life of patients is the reason for seeking medical help, the gold standard of which is surgical correction, and the basic surgical technique is osteotomy (sawing the bone and fixing its fragments with implants) of the first metatarsal. At the same time, an ideal osteotomy should provide initial stability in the early postoperative period. However, a large number of ways to perform osteotomy, as well as the advantages and disadvantages of each of the surgical techniques, do not allow to consider one of them as the most successful. In this regard, the aim of the work was to develop and validate a biomechanical model of osteotomy of the first metatarsal bone to analyze its stability and reliability depending on the type of osteotomy, the degree of displacement of bone fragments, as well as the number of fastening screws. In this study, biomechanical modeling of the most commonly used variants of osteotomy of the first metatarsal bone of the foot in the surgical treatment of its valgus deformity was carried out. For this purpose, 10 models of osteotomies of a separate first metatarsal bone were created, which were then subjected to static loading to analyze their stress-strain state and assess their success. Successful (stable and reliable) treatment options were identified, as well as unsuccessful ones. Two of the ten options considered were unsuccessful – scarf type osteotomies with displacement of bone fragments by 2/3 of its diameter and fixed with a single screw. It was revealed that osteotomies of the chevron type showed higher stability in comparison with scarf osteotomies. As a result, we note that in this study, numerical experiments were conducted for the first time to compare the stability and strength of the most commonly used variants of osteotomies based on a single bone model. A biomechanical model of scarf osteotomy of the first metatarsal bone has been developed and validated on the basis of mechanical experiments
A Model of the Electronic Structure of a FeRh Alloy Undergoing an AntferromagneticβFerromagnetic Phase Transition
Abstract: A new approach to describing the magnetic properties of FeRh alloys is proposed. It is based on two assumptions about the properties of 3d and 4d electrons in these alloys. The first is the assumption that the 4d band is submerged under the Fermi level to a depth that ensures its complete filling at a temperature T = 0 K. The second is the assumption that there are two different spatial distributions of 3d and 4d electrons that are compatible with one atomic structure. The first assumption makes it possible to explain the absence of uncompensated spins of 4d electrons in the low-temperature antiferromagnetic (AFM) phase of FeRh. The second assumption is proposed to explain the strong changes in the spin structure of the FeRh alloy upon the AFMβFM transition, while its atomic structure is almost unchanged. Attempts have been made to predict the new properties of the FeRh alloy that follow from these assumptions. Our second assumption proved to be successful and enabled us to predict the existence of local magnetic moments of 3d electrons in the AFM phase, which are larger than the magnetic moments of Fe ions. Measurements of the magnetic susceptibility of the FeRh alloy in the AFM phase confirmed this prediction. Β© 2022, The Author(s).Ministry of Education and Science of the Russian Federation, Minobrnauka, (AAAA-A18-118020190095-4)This work was carried out within a state task of the Ministry of Education and Science of the Russian Federation (subject βQuantumβ, state registration no. AAAA-A18-118020190095-4)
ΠΠ΅ΡΠΎΠ΄Ρ ΠΎΠΏΡΠ΅Π΄Π΅Π»Π΅Π½ΠΈΡ Π±Π°ΠΊΡΠ΅ΡΠΈΠ°Π»ΡΠ½ΠΎΠ³ΠΎ ΡΠ½Π΄ΠΎΡΠΎΠΊΡΠΈΠ½Π° Π² ΠΌΠ΅Π΄ΠΈΡΠΈΠ½Π΅ ΠΊΡΠΈΡΠΈΡΠ΅ΡΠΊΠΈΡ ΡΠΎΡΡΠΎΡΠ½ΠΈΠΉ (ΠΎΠ±Π·ΠΎΡ)
Dedicated to reviewing the methods for detecting bacterial endotoxin in aqueous solutions and biological fluids, this review is focused on determining the content of endotoxin as a clinically relevant biomarker of sepsis caused by Gram-negative bacteria. The advantages and disadvantages of each method are described, and the characteristics of test systems currently used in clinical practice are listed and compared.Π ΠΎΠ±Π·ΠΎΡΠ΅ ΡΠ°ΡΡΠΌΠΎΡΡΠ΅Π½Ρ ΠΌΠ΅ΡΠΎΠ΄Ρ ΠΎΠΏΡΠ΅Π΄Π΅Π»Π΅Π½ΠΈΡ Π±Π°ΠΊΡΠ΅ΡΠΈΠ°Π»ΡΠ½ΡΡ
ΡΠ½Π΄ΠΎΡΠΎΠΊΡΠΈΠ½ΠΎΠ² Π² Π²ΠΎΠ΄Π½ΡΡ
ΡΠ°ΡΡΠ²ΠΎΡΠ°Ρ
ΠΈ Π±ΠΈΠΎΠ»ΠΎΠ³ΠΈΡΠ΅ΡΠΊΠΈΡ
ΠΆΠΈΠ΄ΠΊΠΎΡΡΡΡ
. ΠΡΠ½ΠΎΠ²Π½ΠΎΠ΅ Π²Π½ΠΈΠΌΠ°Π½ΠΈΠ΅ ΡΠ΄Π΅Π»Π΅Π½ΠΎ ΠΎΠΏΡΠ΅Π΄Π΅Π»Π΅Π½ΠΈΡ ΡΠΎΠ΄Π΅ΡΠΆΠ°Π½ΠΈΡ ΡΠ½Π΄ΠΎΡΠΎΠΊΡΠΈΠ½ΠΎΠ² ΠΊΠ°ΠΊ ΠΊΠ»ΠΈΠ½ΠΈΡΠ΅ΡΠΊΠΈ Π·Π½Π°ΡΠΈΠΌΡΡ
Π±ΠΈΠΎΠΌΠ°ΡΠΊΠ΅ΡΠΎΠ² ΡΠ΅ΠΏΡΠΈΡΠ°, Π²ΡΠ·Π²Π°Π½Π½ΠΎΠ³ΠΎ Π³ΡΠ°ΠΌΠΎΡΡΠΈΡΠ°ΡΠ΅Π»ΡΠ½ΡΠΌΠΈ Π±Π°ΠΊΡΠ΅ΡΠΈΡΠΌΠΈ. ΠΠ±ΡΡΠΆΠ΄Π΅Π½Ρ Π΄ΠΎΡΡΠΎΠΈΠ½ΡΡΠ²Π° ΠΈ Π½Π΅Π΄ΠΎΡΡΠ°ΡΠΊΠΈ ΠΊΠ°ΠΆΠ΄ΠΎΠ³ΠΎ ΠΌΠ΅ΡΠΎΠ΄Π° ΠΈ ΠΏΡΠΈΠ²Π΅Π΄Π΅Π½Ρ ΡΡΠ°Π²Π½ΠΈΡΠ΅Π»ΡΠ½ΡΠ΅ Ρ
Π°ΡΠ°ΠΊΡΠ΅ΡΠΈΡΡΠΈΠΊΠΈ ΠΈΡΠΏΠΎΠ»ΡΠ·ΡΠ΅ΠΌΡΡ
Π² Π½Π°ΡΡΠΎΡΡΠ΅Π΅ Π²ΡΠ΅ΠΌΡ Π² ΠΊΠ»ΠΈΠ½ΠΈΡΠ΅ΡΠΊΠΎΠΉ ΠΏΡΠ°ΠΊΡΠΈΠΊΠ΅ ΡΠ΅ΡΡ-ΡΠΈΡΡΠ΅ΠΌ
Very high frequency gravitational wave background in the universe
Astrophysical sources of high frequency gravitational radiation are
considered in association with a new interest to very sensitive HFGW receivers
required for the laboratory GW Hertz experiment. A special attention is paid to
the phenomenon of primordial black holes evaporation. They act like black body
to all kinds of radiation, including gravitons, and, therefore, emit an
equilibrium spectrum of gravitons during its evaporation. Limit on the density
of high frequency gravitons in the Universe is obtained, and possibilities of
their detection are briefly discussed.Comment: 14 page
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