3,616 research outputs found
Statistic data simulation at estimation of biological system state
It has been shown by the method of statistic data simulation that using samples of small volume characterizing reference state of biological systems results in overstatement of difficulty degree of state integral estimation. It was stated that using asymptotic integral estimations obtained at unlimited increase of modeling reference sample volume is effective as integral estimation of biological system stat
Sinus-preserving modification of eversional carotid endarterectomy: early and late results
Universitatea de Stat de Medicină de Sud Ural, Spitalul Clinic Regional, Celiabinsk, Federația Rusă, Al XIII-lea Congres al Asociației Chirurgilor „Nicolae Anestiadi” și
al III-lea Congres al Societății de Endoscopie, Chirurgie miniminvazivă și Ultrasonografie ”V.M.Guțu” din Republica MoldovaIntroducere: Endarterectomia carotidiană (EAEC) și-a demonstrat avantajul în tratamentul stenozelor hemodinamic semnificative
ale arterei carotide interne (ACI). Tehnica prin eversiune este cea mai populară, însă în versiunea sa standard se asociază cu
traumatizarea frecventă a sinusului carotidian, cu impact negativ asupra reglării vegetative a tonusului vascular și hemodinamicii.
Scopul: Evaluarea eficacității EAEC prin eversiune cu prezervarea nervilor sinusului carotid, comparând rezultatele precoce și la
distanță cu cele ale unui lot de control.
Material și metode: Studiul a inclus 375 pacienți supuși tratamentului chirurgical în Spitalul Clinic Regional Celiabinsk în perioada
anilor 2012-2018. În lotul I (208 bolnavi) EAEC prin eversiune s-a efectuat conform tehnicii standard. În lotul II (167 pacienți) s-a
practicat EAEC modificată, cu prezervarea sinusului. Loturile au fost comparabile în funcție de vârstă, gen, statutul neurologic și
hipertensiv inițial, utilizarea șuntului temporar, timpul de clampaj al ACI și gradul leziunii arteriale carotidiene contralaterale. Pe lângă
înregistrarea parametrilor hemodinamici comuni, a fost evaluată și activitatea vegetativă în baza analizei prospective a variabilității
frecvenței cardiace utilizând ritmocardiografia. La etapa de follow-up, parametrii hemodinamici au fost evaluați la 103 pacienți: cu
păstrarea nervilor sinusului carotidian (39) și după secționarea acestora (64).
Rezultate: În prima zi atât presiunea sistolică, diastolică, cât și presiunea pulsului, precum și frecvența cardiacă au fost mai reduse la
bolnavii după EAEC cu prezervarea sinusului în comparație cu lotul de control. În plus, diminuarea influenței simpatice asupra ritmului
conform ritmocardiografiei a fost notabilă. La pacienții operați cu prezervarea nervilor sinusului carotidian elevarea tensiunii arteriale s-a atestat mai rar, iar doza necesară de remedii antihipertensive a fost mai mică.
Concluzii: S-au constatat diferențe semnificative dintre parametrii, evaluați precoce și la distanță, ai hemodinamicii arteriale
postoperatorii și reglării vegetative a tonusului vascular, în funcție de prezervarea nervilor sinusului carotidian. Practicarea EAEC prin
eversiune cu prezervarea sinusului carotid reduce riscul complicațiilor postoperatorii cauzate de dereglările vegetative.Introduction: Carotid endarterectomy (CEAE) has proven its advantage in correcting hemodynamically significant stenoses of the
internal carotid arteries (ICA). The eversion technique is the most popular, but with its standard procedure, traumatization of carotid
sinus nerves occurs, which has a negative effect on the vegetative regulation of vascular tonus and hemodynamics.
Aim: To evaluate the effectiveness of eversional CEAE with preservation of carotid sinus nerves, by comparing of early and long-term
results with a control group of patients.
Materials and methods: The study included 375 patients treated surgically at the Chelyabinsk Regional Clinical Hospital from 2012
to 2018. In the first group (208 patients), eversional CEAE was performed according to standard technique. In the second group (167
patients), a sinus-preserving modification of CEAE was applied. The groups were comparable by age, sex, baseline neurological
status, baseline hypertension, use of a temporary shunt, ICA cross-clamping time, and degree of contralateral lesion of the carotid
arteries. In addition to common hemodynamic parameters, mediator vegetative activity evaluated based on a prospective analysis
of heart rate variability using rhythmocardiography. In the follow-up period, hemodynamic parameters assessed in 103 patients: with
preservation of the carotid sinus nerves (39) and after their transection (64).
Results: On the 1st day, systolic, diastolic and pulse blood pressure, as well as a heart rate were lower in patients after sinuspreserving CEAE as compared with the control group. In addition, a decrease in sympathetic pressure effect on the rhythm according
to rhythmocardiography was noticeable. In patients operated with the preservation of carotid sinus nerves, an increased blood pressure
is less common and they require a lower dosage of antihypertensive drugs.
Conclusions: There are significant differences between early and distant parameters of postoperative arterial hemodynamics and
vegetative regulation of vascular tonus, depending on preservation of the carotid sinus nerves. Practical application of sinus- preserving
eversional CEAE reduces the risk of postoperative complications due to vegetative dysregulation
The narrowing of the vocational education space as method and condition of forming of professional competences
The article is devoted to the sources of problems of professionalization. Attention is primarily given to the optimal operating conditions of the learning in natural science and psychology. The main principles of effective learning were discussed. It's contains tutor's work and confidence professional-educational spaceВ статье рассматриваются проблемные вопросы профессионализации, указываются их истоки. Отмечается, что в сфере подготовки специалистов естественно-научного профиля наметился очевидный прогресс в отличие от подготовки гуманитариев в силу специфики гуманитарного знания. Раскрывается значение создания доверительного профессионально-образовательного пространства для формирования профессиональных компетенци
Personal approach as a method and means of promoting professional self the subject of labour
This study examines phenomenon of professional self-determination problems and crisis situation with labour resources in Russia, discusses the problems in psychological consultation. Some types such of problems are marked out. The primary purpose of this study was to describe the personal approach to professional consultation. Author discuss the results with the view that personal approach may serve as a method that increase the effect of professional consultationСтатья посвящена профессиональному самоопределению. Отмечается кризисное состояние трудовых ресурсов в России, недостаточная эффективность работы психологов в области оптимизации профессионального самоопределения, обозначены некоторые ключевые причины этого. В статье предлагается личностный подход, реализуемый через многократные доверительные беседы, как метод и средство участия психологии в профессиональном самоопределении молодеж
Crystal nucleation and cluster-growth kinetics in a model glass under shear
Crystal nucleation and growth processes induced by an externally applied
shear strain in a model metallic glass are studied by means of nonequilibrium
molecular dynamics simulations, in a range of temperatures. We observe that the
nucleation-growth process takes place after a transient, induction regime. The
critical cluster size and the lag-time associated with this induction period
are determined from a mean first-passage time analysis. The laws that describe
the cluster growth process are studied as a function of temperature and strain
rate. A theoretical model for crystallization kinetics that includes the time
dependence for nucleation and cluster growth is developed within the framework
of the Kolmogorov-Johnson-Mehl-Avrami scenario and is compared with the
molecular dynamics data. Scalings for the cluster growth laws and for the
crystallization kinetics are also proposed and tested. The observed nucleation
rates are found to display a nonmonotonic strain rate dependency
Thermal deformation of concentrators in an axisymmetric temperature field
Axisymmetric thermal deformations of paraboloid mirrors, due to heating, are examined for a mirror with a optical axis oriented toward the Sun. A governing differential equation is derived using Mushtari-Donnel-Vlasov simplifications, and a solution is presented which makes it possible to determine the principal deformation characteristics
Electron paramagnetic resonance of Gd3+ ions in Ca1-x-yYxGdyF2+x+y crystals
Electron paramagnetic resonance of Ca1-x-yYxGdyF2+x+y single crystals has revealed spectra that are not typical of gadolinium-doped CaF2 crystals. These spectra have a nearly tetragonal symmetry and are most probably caused by Gd3+ ions localized in yttrium clusters. Weak spectra of tetragonal Gd3+ centers, whose parameters are close to those of a cubic gadolinium center caused by an isolated Gd3+ ion, have been also detected. These centers are attributed to isolated Gd3+ ions localized near octahedral rare-earth clusters or their associations. © 2013 Pleiades Publishing, Ltd
dimer paramagnetic centers in lead germanate crystals doped with iron and halogen (Cl-, Br-, F-) ions
The dimer complexes Fe3+-Cl-, Fe3+-Br-, and Fe3+-O2- in ferroelectric lead germanate crystals doped with iron and annealed in chlorine-, bromine-, and fluorine-containing atmospheres have been studied using the electron paramagnetic resonance method. These complexes are formed by Fe3+ ions in the trigonal position of lead and their associated anions located in the interstitial channel of the structure. The positions of the charge-compensating anions in the channel have been discussed based on the analysis of the parameters of the spin Hamiltonian and their temperature dependence. © 2013 Pleiades Publishing, Ltd
Estimating the efficiency of two algorithms for segmentation of digital radiation images of test objects
A mathematical model that describes digital radiation images of test objects is presented. Two algorithms are given for automatic segmentation of digital images distorted by additive noises. The efficiency of the algorithms is estimated based on mathematical modeling
Exploring covalently bonded diamondoid particles with valence photoelectron spectroscopy
We investigated the valence electronic structure of diamondoid particles in
the gas phase, utilizing valence photoelectron spectroscopy. The samples were
singly or doubly covalently bonded dimers or trimers of the lower diamondoids.
Both the bond type and the combination of bonding partners are shown to affect
the overall electronic structure. For singly bonded particles, we observe a
small impact of the bond on the electronic structure, whereas for doubly bonded
particles, the connecting bond determines the electronic structure of the
highest occupied orbitals. In the singly bonded particles a superposition of
the bonding partner orbitals determines the overall electronic structure. The
experimental findings are supported by density functional theory computations
at the M06-2X/cc-pVDZ level of theory.Comment: 7 pages, 7 figure
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