Выбор конечноэкспираторного давления при механической респираторной поддержке (обзор)

Endexpiratory pressure remains one of the few parameters of mechanical respiratory support whose val ues have not been strictly regulated using the evidencebased approach. The absence of «gold standard» for endexpiratory pressure optimization together with its obvious significant contribution to the efficiency and safety of respiratory support has driven the search for the optimal method of choosing its values for several decades.Aim of the review: to identify the optimal methods for determining the values of endexpiratory pressure based on the analysis of its positive and negative effects in the used strategies of mechanical respiratory support.Material and methods. We analyzed 165 papers from the PubMed, Scopus, and RSCI databases of medical and biological publications. Among them we selected 86 sources that most completely covered the following subjects: respiratory support, endexpiratory pressure, recruitment, ventilationperfusion relationships, metabolography, and gas analysis.Results. We outlined the main positive and negative effects of the endexpiratory pressure with regard to both lung biomechanical characteristics and pulmonary perfusion. The evolution of views on the methods of determining optimal values of the endexpiratory pressure was reviewed with the emphasis on a certain «fix ation» of the scientific community in recent decades concerning the opening of the alveoli. The promising techniques based on the analysis of the diffusion capacity of the lungs were presented.Conclusion. Focusing on mechanical lung opening prevents the scientific community from advancing in the optimization of the endexpiratory pressure. Dynamic assessment of pulmonary diffusion efficiency pro vides a new perspective on the issue, offering additional ways to the development of «gold standard».Конечно-экспираторное давление остается сегодня одним из немногих параметров механической респираторной поддержки, значения которых не подверглись строгой регламентации с позиций научно-доказательной медицины. Отсутствие «золотого стандарта» оптимизации конечно экспираторного давления в совокупности с очевидным значимым вкладом в эффективность и безопасность респираторной поддержки заставляет в течение десятилетий продолжать поиск оптимального метода выбора его значений.Цель обзора. Выявление оптимальных методов определения значений конечноэкспираторного давления на основе анализа его положительных и негативных эффектов в применяемых стратегиях механической респираторной поддержки.Материалы и методы. Анализировали 165 научных работ из баз данных медицинских и биологических публикаций PubMed, Scopus, РИНЦ. Из них отобрали 86 источников, наиболее полно отражающих информацию по следующим разделам: респираторная поддержка, конечно-экспираторное давление, рекрутмент, вентиляционно-перфузионные отношения, метаболография, газоанализ.Результаты. Сформулировали основные положительные и негативные эффекты конечно-экспираторного давления в отношении как биомеханических характеристик легких, так и легочной пер фузии. Провели анализ эволюции взглядов на методики определения оптимальных значений конечно-экспираторного давления, в котором сделали акцент на некую «зацикленность» научного сообщества в последние десятилетия в отношении раскрытия альвеол. Привели перспективные методики, основанные на анализе диффузионного потенциала легких.Заключение. Фокусировка внимания на механическом раскрытии легких не позволяет продвинуться научному обществу в оптимизации конечно-экспираторного давления. Методы динамической оценки эффективности легочной диффузии позволяют взглянуть на проблему под новым углом, открывая дополнительные пути «золотого стандарта»

Five types of blow-up in a semilinear fourth-order reaction-diffusion equation: an analytic-numerical approach

Five types of blow-up patterns that can occur for the 4th-order semilinear parabolic equation of reaction-diffusion type u_t= -\Delta^2 u + |u|^{p-1} u \quad {in} \quad \ren \times (0,T), p>1, \quad \lim_{t \to T^-}\sup_{x \in \ren} |u(x,t)|= +\iy, are discussed. For the semilinear heat equation $u_t= \Delta u+ u^p$, various blow-up patterns were under scrutiny since 1980s, while the case of higher-order diffusion was studied much less, regardless a wide range of its application.Comment: 41 pages, 27 figure

Exact travelling wave solutions of a beam equation

In this paper we make a full analysis of the symmetry reductions of a beam equation by using the classical Lie method of infinitesimals and the nonclassical method. We consider travelling wave reductions depending on the form of an arbitrary function. We have found several new classes of solutions that have not been considered before: solutions expressed in terms of Jacobi elliptic functions, Wadati solitons and compactons. Several classes of coherent structures are displayed by some of the solutions: kinks, solitons, two humps compactons.17 página

Continuous Symmetries of Difference Equations

Lie group theory was originally created more than 100 years ago as a tool for solving ordinary and partial differential equations. In this article we review the results of a much more recent program: the use of Lie groups to study difference equations. We show that the mismatch between continuous symmetries and discrete equations can be resolved in at least two manners. One is to use generalized symmetries acting on solutions of difference equations, but leaving the lattice invariant. The other is to restrict to point symmetries, but to allow them to also transform the lattice.Comment: Review articl

Dynamics of the Universe with global rotation

We analyze dynamics of the FRW models with global rotation in terms of dynamical system methods. We reduce dynamics of these models to the FRW models with some fictitious fluid which scales like radiation matter. This fluid mimics dynamically effects of global rotation. The significance of the global rotation of the Universe for the resolution of the acceleration and horizon problems in cosmology is investigated. It is found that dynamics of the Universe can be reduced to the two-dimensional Hamiltonian dynamical system. Then the construction of the Hamiltonian allows for full classification of evolution paths. On the phase portraits we find the domains of cosmic acceleration for the globally rotating universe as well as the trajectories for which the horizon problem is solved. We show that the FRW models with global rotation are structurally stable. This proves that the universe acceleration is due to the global rotation. It is also shown how global rotation gives a natural explanation of the empirical relation between angular momentum for clusters and superclusters of galaxies. The relation $J \sim M^2$ is obtained as a consequence of self similarity invariance of the dynamics of the FRW model with global rotation. In derivation of this relation we use the Lie group of symmetry analysis of differential equation.Comment: Revtex4, 22 pages, 5 figure

Identification of a novel susceptibility locus at 13q34 and refinement of the 20p12.2 region as a multi-signal locus associated with bladder cancer risk in individuals of European ancestry

Contains fulltext : 167299.pdf (publisher's version ) (Closed access)Candidate gene and genome-wide association studies (GWAS) have identified 15 independent genomic regions associated with bladder cancer risk. In search for additional susceptibility variants, we followed up on four promising single-nucleotide polymorphisms (SNPs) that had not achieved genome-wide significance in 6911 cases and 11 814 controls (rs6104690, rs4510656, rs5003154 and rs4907479, P < 1 x 10(-6)), using additional data from existing GWAS datasets and targeted genotyping for studies that did not have GWAS data. In a combined analysis, which included data on up to 15 058 cases and 286 270 controls, two SNPs achieved genome-wide statistical significance: rs6104690 in a gene desert at 20p12.2 (P = 2.19 x 10(-11)) and rs4907479 within the MCF2L gene at 13q34 (P = 3.3 x 10(-10)). Imputation and fine-mapping analyses were performed in these two regions for a subset of 5551 bladder cancer cases and 10 242 controls. Analyses at the 13q34 region suggest a single signal marked by rs4907479. In contrast, we detected two signals in the 20p12.2 region-the first signal is marked by rs6104690, and the second signal is marked by two moderately correlated SNPs (r(2) = 0.53), rs6108803 and the previously reported rs62185668. The second 20p12.2 signal is more strongly associated with the risk of muscle-invasive (T2-T4 stage) compared with non-muscle-invasive (Ta, T1 stage) bladder cancer (case-case P </= 0.02 for both rs62185668 and rs6108803). Functional analyses are needed to explore the biological mechanisms underlying these novel genetic associations with risk for bladder cancer

Identification of a novel susceptibility locus at 13q34 and refinement of the 20p12.2 region as a multi-signal locus associated with bladder cancer risk in individuals of European ancestry

Candidate gene and genome-wide association studies (GWAS) have identified 15 independent genomic regions associated with bladder cancer risk. In search for additional susceptibility variants, we followed up on four promising single-nucleotide polymorphisms (SNPs) that had not achieved genome-wide significance in 6911 cases and 11 814 controls (rs6104690, rs4510656, rs5003154 and rs4907479, P < 1 × 10−6), using additional data from existing GWAS datasets and targeted genotyping for studies that did not have GWAS data. In a combined analysis, which included data on up to 15 058 cases and 286 270 controls, two SNPs achieved genome-wide statistical significance: rs6104690 in a gene desert at 20p12.2 (P = 2.19 × 10−11) and rs4907479 within the MCF2L gene at 13q34 (P = 3.3 × 10−10). Imputation and fine-mapping analyses were performed in these two regions for a subset of 5551 bladder cancer cases and 10 242 controls. Analyses at the 13q34 region suggest a single signal marked by rs4907479. In contrast, we detected two signals in the 20p12.2 region—the first signal is marked by rs6104690, and the second signal is marked by two moderately correlated SNPs (r2 = 0.53), rs6108803 and the previously reported rs62185668. The second 20p12.2 signal is more strongly associated with the risk of muscle-invasive (T2-T4 stage) compared with non-muscle-invasive (Ta, T1 stage) bladder cancer (case–case P ≤ 0.02 for both rs62185668 and rs6108803). Functional analyses are needed to explore the biological mechanisms underlying these novel genetic associations with risk for bladder cancer