Number of results to display per page
Search Results
782. 3D echocardiography - a useful method for cardiovascular risk assessment in end-stage renal disease patients
- Creator:
- Kovářová, Magdaléna, Žilinská, Zuzana, Páleš, Ján, Kužmová, Zuzana, Gažová, Andrea, Smaha, Juraj, Kužma, Martin, Jackuliak, Peter, Štvrtinová, Viera, Kyselovič, Ján, and Payer, Juraj
- Format:
- počítač and online zdroj
- Type:
- model:article and TEXT
- Subject:
- fyziologie člověka, lékařství, human physiology, medicine, End-stage chronic kidney disease, Hemodialysis, Kidney transplantation, Ankle-brachial index, Echocardiography, 14, and 612
- Language:
- English
- Description:
- a1_Patients with chronic kidney disease (CKD) have an increased risk of premature mortality, mainly due to cardiovascular causes. The association between hemodialysis and accelerated atherosclerosis has long been described. The ankle-brachial index (ABI) is a surrogate marker of atherosclerosis and recent studies indicate its utility as a predictor of future cardiovascular disease and all-cause mortality. The clinical implications of ABI cut-points are not well defined in patients with CKD. Echocardiography is the most widely used imaging method for cardiac evaluation. Structural and functional myocardial abnormalities are common in patients with CKD due to pressure and volume overload as well as non-hemodynamic factors associated with CKD. Our study aimed to identify markers of subclinical cardiovascular risk assessed using ABI and 2D and 3D echocardiographic parameters evaluating left ventricular (LV) structure and function in patients with end-stage renal disease (ESRD) (patients undergoing dialysis), patients after kidney transplantation and non-ESRD patients (control). In ESRD, particularly in hemodialysis patients, changes in cardiac structure, rather than function, seems to be more pronounced. 3D echocardiography appears to be more sensitive than 2D echocardiography in the assessment of myocardial structure and function in CKD patients. Particularly 3D derived end-diastolic volume and 3D derived LV mass indexed for body surface appears to deteriorate in dialyzed and transplanted patients. In 2D echocardiography, myocardial mass represented by left ventricular mass/body surface area index (LVMI) appears to be a more sensitive marker of cardiac structural changes, compared to relative wall thickness (RWT), left ventricle and diastolic diameter index (LVEDDI) and left atrial volume index (LAVI)., a2_We observed a generally favorable impact of kidney transplantation on cardiac structure and function; however, the differences were non-significant. The improvement seems to be more pronounced in cardiac function parameters, peak early diastolic velocity/average peak early diastolic velocity of mitral valve annulus (E/e´), 3D left ventricle ejection fraction (LV EF) and global longitudinal strain (GLS). We conclude that ABI is not an appropriate screening test to determine the cardiovascular risk in patients with ESRD., Magdaléna Kovářová, Zuzana Žilinská, Ján Páleš, Zuzana Kužmová, Andrea Gažová, Juraj Smaha, Martin Kužma, Peter Jackuliak, Viera Štvrtinová, Ján Kyselovič, Juraj Payer., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
783. 3D how much can we trust some moment tensors or an attempt of seismic moment error estimation
- Creator:
- Kolář, Petr
- Format:
- print, bez média, and svazek
- Type:
- article, články, model:article, and TEXT
- Subject:
- Geologie. Meteorologie. Klimatologie, seizmicita, seismicity, seismic moment tensor inversion, error estimation, seismic moment decomposition, 7, and 551
- Language:
- English
- Description:
- During routine processing of selected events of an active KTB experiment it has appeared doubts concerning data reliability and consequently the reliability of results based on them. In the paper 3 events are studied in detail, full seismic moment tensors, as well as their errors, are determined (by non-linear inversion of P/SH waves ratios). It is shown that for the processed low constrained data moment tensor (MT) can be determined, however the relative error is of order of first tens of percent; the results also considerably depend on the way of data picking, used medium model, way of Cost function construction, etc. Any subsequent geophysical interpretation therefore should takes into account this uncertainty. MTs are finally decomposed into DC and non-DC parts, MTs errors are also transformed., Petr Kolář., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
784. 3D microscopic imaging and evaluation of tubular tissue architecture
- Creator:
- Jiří Janáček, Čapek, M., Michálek, J., Petr Karen, and Lucie Kubínová
- Format:
- Type:
- article, články, model:article, and TEXT
- Subject:
- Fyziologie člověka a srovnávací fyziologie, mozek, brain, confocal microscopy, capillaries, skeletal muscle, image analysis, 14, and 612
- Language:
- English
- Description:
- 3D microscopy and image analysis provide reliable measurements of length, branching, density, tortuosity and orientation of tubular structures in biological samples. We present a survey of methods for analysis of large samples by measurement of local differences in geometrical characteristics. The methods are demonstrated on the structure of the capillary bed in a rat brain., J. Janáček ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
785. 3D monitoring of active fault structures in the Krupnik-Kresna seismic zone, SW Bulgaria
- Creator:
- Dobrev, Nikolai
- Format:
- print, bez média, and svazek
- Type:
- article, články, model:article, and TEXT
- Subject:
- Geologie. Meteorologie. Klimatologie, seizmické oblasti, seismic regions, Bulharsko, Bulgaria, 3D monitoring, active faults, co-seismic displacements, Krupnik-Kresna seismic zone, SW Bulgaria, 7, and 551
- Language:
- English
- Description:
- The present paper concerns long-term 3D monitoring of active fault structures in the Krupnik-Kresna seismic zone, SW Bulgaria with the use of extensometers TM71. The purpose is to establish the real rates of fault movements in the most seismically active area in Bulgaria. Three points were installed (B6 on Krupnik Fault, and K5 and K12 on Struma Fault), which indicate a recent activity. The fault movements are characteristic with “calm” periods, linear slips, accelerations and sudden displacements. Different regimes of dynamics have been established corresponding to different periods. The greatest dynamics is found at monitoring point B6 along Krupnik Fault: for the whole period of observation the trends are calculated as left lateral slip with 1.88 mm/a and a thrusting with 1.59 mm/a with high correlation coefficients. Co-seismic displacements from local and distant earthquakes were recorded. The significant impact was from M=7.4, 17 August, 1999, Izmit Earthquake, Turkey, showing a shortening of 8.34 mm, a right-lateral slip of 5.09 mm and a thrusting of 0.96 mm. After that, for a short period of time the regime of movement on fault was changed. Movements on the Struma system reveal lower rates. Both points show left-lateral movements, 0.28 mm/a at K5 and 0.09 mm/a at K12, and thrusting with 0.11 mm/a at K5 and 0.72 mm/a at K12., Nikolai Dobrev., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
786. 3D monitoring of active faults and slope movements in three Bulgarian sites included in cost 625 project
- Creator:
- Dobrev, Nikolai and Avramova-Tacheva, Elka
- Format:
- print, bez média, and svazek
- Type:
- article, články, model:article, and TEXT
- Subject:
- Geologie. Meteorologie. Klimatologie, tenzometrie, svahy, extensometry, slopes (physical geography), fault, slope movement, 3D monitoring, 7, and 551
- Language:
- English
- Description:
- The present paper shows the results of 3D monitoring with the use of extensomet ers TM71 performed in Bulgaria in the framework of COST Action 625. This research was performed in selected areas: Simitli graben that is the most seismoactive area in Bulgaria; Madara plat eau - rock scarp with historical monument affe cted by rock toppling; East Rhodopes area - a possibly active fault zone and a large landslide. The most impressive results were established at Simitli graben area with the rate of 2.73 mm/year sinistral movement of Krupnik Fault. Local earthquakes located at NE part of the graben usually influence the movements along this fault. An acceleration of the left latera l movements during calm periods has been established, and respectively, the movements stop (or going in opposite direction) during seismic activity. At Madara site, the results from the 15 years monitoring show subsidence of rock s lices by 0.9 mm per year and si milar rate movement of the slices to South direction. Influence from Izmit earthquake, Vrancea earthquakes and local ones have been established. The monitoring of the fault at General Geshe vo Village, East Rhodopean area started in 2003. The first results show mainly gravitational movements - subsidence of NE block 1.5 mm/year., Nikolai Dobrev and Elka Avramova-Tacheva., and Obsahuje bibliografické odkazy
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
787. 3D monitoring of the selected active tectonic structures in Poland, Italy and Greece
- Creator:
- Cacoń, Stefan, Kontny, Bernard, and Bosy, Jarosław
- Format:
- print, bez média, and svazek
- Type:
- article, články, model:article, and TEXT
- Subject:
- Geologie. Meteorologie. Klimatologie, GPS sítě, GPS netwoks, active tectonics, geodetic monitoring system, local GPS network, crack gauge observation, 7, and 551
- Language:
- English
- Description:
- The paper presents the results of geodyn amic research in the fram e of the project COST 625 relating to active tectonic structures’ monitoring on the selected areas in Poland, Italy and Greece. Research was realised using a self-developed control and measurement system. The resu lts of researches for period 2000-2006 indi cate slight movements of observatio n points in the Sudety Mts. reaching several millimetres. However, the results confirm recent mobility of tectonic structures o f this area. Research realised in the Mediterranean Region objects - Gargano, Norcia (Italy) and Kaparelli (Greece) - indicate movements of observation points reaching over a dozen millimetres, particularly on the Gargano area. Continuation of cyclic control measurements on these objects is fully justified ., Stefan Cacoń, Bernard Kontny and Jarosław Bosy., and Obsahuje bibliografické odkazy
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
788. 3D numerical model of the spherical particle saltation in a channel with a rough fixed bed
- Creator:
- Lukerchenko, Nikolay, Piatsevich, Siarhei, Chára, Zdeněk, and Vlasák, Pavel
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- 3D saltation model, bed-load transport, particle-bed collision, particle rotation, particle lateral dispersion, 3D model saltace, pohyb splavenin, kolise částice-dno, rotace částic, and příčná disperze částic
- Language:
- Slovak
- Description:
- The paper describes a 3D numerical model of the spherical particle saltation. Two stages of particle saltation were distinguished - the particle free motion in water and the particle-bed collision. The particle motion consists of the translational and rotational particle motion. A stochastic method of calculation of the particle-bed collision was developed. The collision height and the contact point were defined as random variables. Impulse equations were used and the translational and angular velocity components of the moving particle immediately after the collision were expressed as functions of the velocity components just before the collision. The dimensionless coefficients of the drag force and drag torque were determined as functions of both translational and rotational Reynolds numbers. The model is in good agreement with known experimental data. Examples of calculation of the particles’ lateral dispersion and the mean absolute values of the deviation angle of the particle trajectory are presented. and Studie popisuje 3D numerický model saltačního pohybu kulovité částice, v němž jsou uvažována dvě fáze saltačního pohybu - volný pohyb částice v proudící vodě a kolise částice se dnem. Model počítá s translačním i rotačním pohybem částice. Byla vyvinuta stochastická metoda výpočtu kolise částice se dnem. Kolizní výška a kontaktní bod byly definovány jako náhodné proměnné. Byla použita soustava momentových rovnic a složky translační a rotační rychlosti pohybující se částice po kolizi byly vyjádřeny jako funkce složek rychlosti těsně před kolizí. Bezrozměrné koeficienty odporu částice a odporu rotující částice byly určeny jako funkce translačního i rotačního Reynoldsova čísla částice. Výsledky modelu jsou v dobré shodě se známými experimentálními daty. Studie presentuje příklady výpočtu příčné disperze částice a střední absolutní hodnoty deviačního úhlu trajektorie částice.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
789. 3D numerical modeling of flow characteristics in an open channel having in-line circular vegetation patches with varying density under submerged and emergent flow conditions
- Creator:
- Tariq, Hasnain, Ghani, Usman, Anjum, Naveed, and Pasha, Ghufran Ahmed
- Format:
- počítač and online zdroj
- Type:
- model:article and TEXT
- Subject:
- vegetation patches, open channel, variable patch density, flow velocity, and turbulence
- Language:
- Slovak
- Description:
- In the marine ecological system, the prime role of water management and durability of an ecosystem is being played by the vegetation patches. The vegetation patches in open channels can significantly affect the flow velocity, discharge capacity and hinder energy fluxes, which ultimately helps in controlling catastrophic floods. In this study, the numerical simulation for turbulent flow properties, i.e. velocity distribution, Reynolds stresses and Turbulent Intensities (TI) near the circular vegetation patches with progressively increasing density, were performed using the computational fluid dynamics (CFD) code ANSYS FLUENT. For examination of the turbulent flow features in the presence of circular patches with variable densities, Reynolds averaged Navier-Stokes equations, and Reynolds stress model (RSM) were employed. The numerical investigation was performed in the presence of in-line emergent and submerged patches having variable vegetation density in the downstream direction. Two of the cases were investigated with three circular patches having a clear gap to patch diameter ratio of La/D = 1 (where La is the clear spacing between the vegetation patches and D is the diameter of the circular patch), and the other two cases were analyzed with two patches having a clear gap ratio of La/D = 3. The case with a clear gap ratio (La/D = 3) showed 10.6% and 153% inflation in the magnitude of longitudinal velocity at the downstream of the sparse patch (aD = 0.8) and upstream of the dense patch (aD = 3.54), respectively (where aD is the flow blockage, in which “a” represents the patch frontal area and “D” represents the patch diameter). The velocity was reduced to 94% for emergent and 99% for submerged vegetation due to successive increase in vegetation density made by introducing a middle patch which reduced the clear gap ratio (La/D = 1). For La/D = 1, the longitudinal velocities at depth z = 15cm were increased by 319% than at depth z = 6cm at the downstream of the dense patch (aD = 3.54). Whereas it was observed to 365% higher in the case of La/D = 3. The magnitude of turbulent characteristics was observed 36% higher for submerged vegetation cases having a clear gap ratio of La/D = 1. The successive increase in the patch density reduced the Reynolds stresses, turbulent kinetic energy and turbulent intensities significantly within the gap region. The major reduction in the flow velocities and turbulent properties in the gaps provides a stable environment for aquatic ecosystems nourishment and fosters sediment deposition, and supports further vegetation growth.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
790. 3D object recognition using octree model and fast search algorithm
- Creator:
- Lee, Young Jae, Abraham , Ajith, and Kim , Dong Hwa
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- 3D object recognition, octree model, and pattern analysis
- Language:
- English
- Description:
- This paper presents a new approach to 3D object recognition by using an Octree model library (OML) I, II and fast search algorithm. The fast search algorithm is used for finding the 4 pairs of feature points to estimate the viewing direction uses on effective two level database. The method is based on matching the object contour to the reference occluded shapes of 49, 118 viewing directions. The initially bestmatched viewing direction is calibrated by searching for the 4 pairs of feature points between the input image and the image projected along the estimated viewing direction. At this point, the input shape is recognized by matching it to the projected shape. The computational complexity of the proposed method is shown to be O(n^2) in the worst case, and that of the simple combinatorial method of O(m^4,n^2), where n and m denote the number of feature points of the 3D model object and the 2D object, respectively.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public