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Accumulating experimental evidence has indicated that long non-coding RNAs (lncRNAs) are critical for the regulation of cellular biological processes implicated in many human diseases. However, only relatively few experimentally supported lncRNA-disease associations have been reported. Developing effective computational methods to infer lncRNA-disease associations is becoming increasingly important. Current network-based algorithms typically use a network representation to identify novel associations between lncRNAs and diseases. But these methods are concentrated on specific entities of interest (lncRNAs and diseases) and they do not allow to consider networks with more than two types of entities. Considering the limitations in previous computational methods, we develop a new global network-based framework, LncRDNetFlow, to prioritize disease-related lncRNAs. LncRDNetFlow utilizes a flow propagation algorithm to integrate multiple networks based on a variety of biological information including lncRNA similarity, protein-protein interactions, disease similarity, and the associations between them to infer lncRNA-disease associations. We show that LncRDNetFlow performs significantly better than the existing state-of-the-art approaches in cross-validation. To further validate the reproducibility of the performance, we use the proposed method to identify the related lncRNAs for ovarian cancer, glioma, and cervical cancer. The results are encouraging. Many predicted lncRNAs in the top list have been verified by the biological studies.

Background There is a lack of comprehensive echocardiographic data to allow discrimination of normal versus abnormal mechanical prosthetic tricuspid valve (MPTV) leaflet function. The identification of such parameters is essential to optimize diagnostic and therapeutic measures. Methods The authors investigated bileaflet MPTV function by comparing transthoracic echocardiographic data from 21 episodes of leaflet dysfunction due to valve thrombosis in 12 patients with data from 56 individuals with normal MPTV function. All episodes of dysfunction were confirmed by transesophageal echocardiography and/or cine fluoroscopy. Transthoracic echocardiography–derived two-dimensional, color, and spectral Doppler variables, including MPTV peak early diastolic velocity (E velocity), mean gradient, pressure half-time, time-velocity integral (TVI) of the MPTV, ratio of TVIMPTV to TVI of the left ventricular outflow tract (LVOT) and TVI of the right ventricular outflow tract (RVOT), and continuity-derived effective orifice area, were measured in both groups. Results Most episodes of MPTV dysfunction resulted from simultaneous involvement of both leaflets (57%), with leaflet(s) often immobilized in the open or semiopen position (71%). Transthoracic and transesophageal echocardiography performed similarly in detecting abnormal leaflet motion (90% vs 88%, P = .68), whereas transesophageal echocardiography was better in identifying MPTV thrombosis (31% vs 14%, respectively, P = .01). Color Doppler demonstrated flow propagation abnormalities in 67% of episodes of leaflet dysfunction but not in the control group (P 1.6 m/sec, mean gradient > 5 mm Hg, PHT > 157 msec, TVIMPTV > 42 cm, TVIMPTV/TVILVOT > 2.3, TVIMPTV/TVIRVOT > 3.0, and continuity-derived effective orifice area ≤ 1.1 cm2, with most variables showing high and similar accuracy (area under the curve ≥ 95%). Conclusions This study represents the first comprehensive echocardiographic assessment of MPTV leaflet dysfunction that provides parameters and criteria to distinguish normal versus abnormal prosthetic valve function.

Aim: To detect and quantify early subtle left ventricular (LV) systolic dysfunction using Tissue Doppler Imaging in type 2 diabetic patients with apparently normal LV ejection fraction. Methods: Ninety age and sex matched subjects were enrolled in the study, sixty of them were suffering from type 2 diabetes mellitus (DM) whom were divided according to HbAlc into 2 groups, 30 uncontrolled diabetic patients with HbAlc > 8% and 30 controlled diabetic patients with HbAlc

We propose a method to evaluate public transport network vulnerability. We study the evolution of the passenger Volume Over Capacity (VOC) ratio throughout the network to measure the spatial and temporal extent of the impacts caused by an unplanned service segment disruption. The VOC ratio provides an indication of the on-board travel comfort, an important level-of-service indicator, as well as reflects the residual capacity for absorbing additional demand. Because of the dynamic nature of public transport systems, disturbances propagate through the network in both time and space. Our modelling approach is able to capture transit system dynamics and quantify the extent to which the network exhibits spillover effects. We apply the method to the case of the rapid public transport system of Stockholm Sweden We demonstrate how the changes in network saturation and the corresponding recovery time can be quantified.

We present observations of Io's Loki Patera taken with the 10-m Keck telescopes between 1998 and 2016. Adding these data to those published by Rathbun and Spencer (2006) and the Gemini data of de Kleer and de Pater (2016a, 2017) results in a database of 3.5–3.8 µm emission from Loki Patera over almost 3 decades. Data presented here contain adaptive optics (AO) observations of Io's sunlit hemisphere at wavelengths between 1.6 and 5 µm, AO observations of Io in eclipse at 2–5 µm, and non-AO observations of Io in eclipse at 1.6–12 µm. The non-AO data were taken in September of 1999, during the early phase of a brightening event that was documented by Howell et al. (2001). Dual-component Io Flow model (IFM) fits to our 1999 observations show a mostly cool lava crust over almost the entire patera floor, with a relatively small hotter component making up less than 1% of the total area, consistent with previous observations. The 30-year timeline of Loki Patera revealed that, after an apparent cessation of, or change in, brightening events in 2002, Loki Patera became active again in 2009. The more recent activity may have a slightly shorter periodicity than observed by Rathbun et al. (2002), and the direction of flow propagation appears to have reversed. Since 2009 the flow direction is in the clockwise direction, starting in the north or north-east corner and propagating along the patera towards the south-west. During the Galileo era the propagation was in the counter-clockwise direction, starting in the south-west and propagating towards the east. Both the 30-year timeline and the 1.6–12 µm spectrum that was obtained during the brightening event in 1999 agree well with Matson et al.’s (2006) overturning lava lake model, as modified by de Kleer and de Pater (2017).

We consider dynamic equilibria for flows over time under the fluid queuing model. In this model, queues on the links of a network take care of flow propagation. Flow enters the network at a single source and leaves at a single sink. In a dynamic equilibrium, every infinitesimally small flow particle reaches the sink as early as possible given the pattern of the rest of the flow. Although this model has been examined for many decades, progress has been relatively recent. In particular, the derivatives of dynamic equilibria have been characterized as thin flows with resetting, which allows for more structural results. Our two main results are based on the formulation of thin flows with resetting as a linear complementarity problem and its analysis. We present a constructive proof of existence for dynamic equilibria if the inflow rate is right-monotone. The complexity of computing thin flows with resetting, which occurs as a subproblem in this method, is still open. We settle it for the class of two-terminal, series-parallel networks by giving a recursive algorithm that solves the problem for all flow values simultaneously in polynomial time.

In this paper, a novel mesoscopic multilane model is proposed to enable simultaneous simulation of mandatory and discretionary lane-changing behaviors to realistically capture multilane traffic dynamics. The model considers lane specific fundamental diagrams to simulate dynamic heterogeneous lane flow distributions on expressways. Moreover, different priority levels are identified according to different lane-changing motivations and the corresponding levels of urgency. Then, an algorithm is proposed to estimate the dynamic mandatory and discretionary lane-changing demands. Finally, the lane flow propagation is defined by the reaction law of the demand–supply functions, which can be regarded as an extension of the Incremental-Transfer and/or Priority Incremental-Transfer principles. The proposed mesoscopic multilane cell transmission model is calibrated and validated on a complex weaving section of the State Route 241 freeway in Orange County, California, showing both the positive and negative impact of lane changing maneuvers, e.g., balancing effect and capacity drop, respectively. Moreover, the empirical study verifies that the model requires no additional data other than the cell transmission model does. Thus, the proposed model can be deployed as a simple simulation tool for accessing dynamic mesoscopic multilane traffic state from data available to most management centers, and also the potential application in predicting the impact of traffic incident or lane control strategy.

Taking time-varying parking demands and supplies into account, this paper develops a dynamic parking choice model to simulate drivers’ searching for parking spaces between parking lots. In this study, each parking lot has one access passage and vehicles can move or wait for entering the park in the access passage. The flow propagation formula in the access passage of parking lots is established to obtain the number of vehicles entering the parking lot from the access passage within each time interval. This paper brings forward the instantaneous dynamic user-optimal condition of dynamic parking choice, constructs an equivalent variational inequality (VI) model and develops a diagonalization algorithm to solve the model. A numerical example demonstrates the rate of in-flow, the rate of out-flow, link flow, instantaneous travel time on each link or access passage of the parking lot, and the amount and routes of cruising traffic at each time point.

Purpose – Whether a fire can be initiated in an explosion accident depends on the explosion and deflagration process. In the methane-air explosion in a tunnel, the flame accelerates from the ignition point. However, where it begins to decelerate is not clear. The purpose of this paper is to examine the explosion overpressure, flow and flame propagation beyond the premixed area of methane-air in a tunnel. Design/methodology/approach – The numerical simulation was used to study the explosion processes of methane-air mixtures in a tunnel. Based on the numerical simulation and its analysis, the explosion overpressure, flow and flame propagation rules beyond the premixed area were demonstrated for a methane-air explosion. Findings – The peak overpressure of methane-air mixture explosion was observed to reach its maximum beyond the original premixed area of methane-air. The hazardous effects beyond the premixed area may be stronger than those within the premixed area for a methane-air explosion in a tunnel. Under the conditions of this study, the ratio between the length of combustion area (40 m) and that of original premixed area (28 m) reaches 1.43. Originality/value – Little attention has been devoted to investigating the explosion overpressure, flow and flam propagations beyond the original premixed area of methane-air in a tunnel. Based on the numerical simulation and the analysis, the propagation rule of overpressure wave and flow inside and outside the space occupied by methane/air mixture at the volume fraction of 9.5 percent in a tunnel were obtained in this work.

The Ni silicides and Si metal-semiconductor contacts are a vital element in the state-of-the-art commercial transistor devices. The contact formation process needs to be precisely engineered in order to achieve reproducible electrical properties over billions of transistors, especially for ultra-scaled transistors when contact resistance contribution is significant. The latest source/drain (S/D) engineering technology designs the S/D crystal structure (e.g. intentional incorporation of stacking faults) that strains the channel to enhance device performance. Understanding the role of structural alternation, or defects, in Si-Ni reaction is therefore important in achieving precise control of the contact formation process at an atomic scale. Here, we present a study of Si-Ni reaction by lattice-resolved in-situ transmission electron microscopy (TEM) and found that presence of defects in Si can fundamentally change the silicide nucleation mechanism and growth behavior. We use vapor-liquid-solid (VLS) grown Si nanowire (NW) as the Si source and incorporate two types of defects (twin boundaries (TB) running down NW axial direction and grain boundaries (GB) on NW surface). Si NWs are dispersed on silicon nitride (50nm) TEM membrane and react with photolithography defined Ni electrodes, at 300C on an in-situ TEM heating stage. Dynamic high resolution TEM imaging resolves the axial growth of NiSi2 into Si NW as layer-wise repeating nucleation and propagation of NiSi2 (111) plane. Previously reported studies show 2D Ni silicides nucleate homogeneously in the center of defect-free NWs (Figure a-b), and the growth proceeds in a layer-by-layer manner with long incubation time between sequential layer growth (Figure c). We captured the nucleation of each NiSi2 layer at the initial stage and demonstrated that TB and GBs are preferred heterogeneous nucleation sites. An example of nucleation and step propagation from the TB is shown in Figure d. Experimentally measured growth rate (Figure e) qualitatively fit with our analytical model based on classic nucleation theory, which consider the energy of different defects. Defective sites with the heterogeneous nucleation barrier in descending order are TB, "corner", and GB, (Figure f) suggesting that higher degree of defectivity suppresses the nucleation barrier more effectively. We further extend our model to depict NiSi2 nucleation as a biased random walk stochastic process and show that twin defects in NiSi2have high interfacial energies (in contrast to other typical FCC materials like copper or silicon). We calculate this defect energy, which together with our experimental observations, should alert and guide contact silicide formation processes and strain engineering in future Si-based technology nodes. Figure captions: (a-b) homogeneous nucleation of Ni silicide in a single crystal Si NW (c) Layer-by-layer repeating homogeneous nucleation in silicide growth (d) NiSi2 heterogeneously nucleates from the “corner” site. Scale bar is 3 nm. (e) The silicide grows at a steady rate when guided by the TB. Inset shows layer-by-layer growth behaviour in the heterogeneous nucleation NiSi2 growth. (f) Reduction in the nucleation barrier at different heterogeneous sites noted in the inset schematic which is a 3D view of three different heterogeneous nucleation sites in a defective Si nanowire.

This article extends the stochastic cell transmission model (SCTM) to simulate traffic flows on networks with stochastic demand and supply. The SCTM divides a roadway segment into cells and accepts the means and variances of stochastic travel demand and supply functions as exogenous inputs, and produces the corresponding cell traffic densities over time. This article defines the rules of flow propagation for freeway corridors, traffic merges/diverges and signalised junctions based on a kind of link-node model. In the numerical studies, we simulate the proposed model with a hypothetical network. We apply the SCTM to estimate the queues and delays at signalised intersections. Compared with some well-known delay and queue estimation formulas, e.g. Webster, Beckmann, McNeil and Akcelik, the results show good consistency between the SCTM and these formulas. In addition, the SCTM describes the temporal behaviour of the queue and delay distributions at signalised junctions with stochastic supply functions and (n...

Various applications like finding web communities, detecting the structure of social networks , or even analyzing a graph’s structure to uncover Internet attacks are just some of the applications for which community detection is important. In this paper, we propose an algorithm that finds the entire community structure of a network, based on local interactions between neighboring nodes and on an unsupervised distributed hierarchical clustering algorithm. In this paper, we describe two novel community detection algorithms, one for full graph communities detection and one for single community detection. The novelty of the first proposed approach, named SCCD (to stand for Synthetic Coordinate Community Detection), is the fact that the algorithm is based on the use of Vivaldi synthetic network coordinates computed by a distributed algorithm . We also present an extended version of said algorithm, modified to deal efficiently with community detection on dynamic graphs . Finally, we present a new algorithm which partially analyzes a graph to detect the community of a single node. The current paper not only presents two efficient community finding algorithms, but also demonstrates that synthetic network coordinates could be used to derive efficient solutions to a variety of problems. Experimental results and comparisons with other methods from the literature are presented for a variety of benchmark graphs with known community structure, derived by varying a number of graph parameters and real dataset graphs. The experimental results and comparisons to existing methods with similar computation cost on real and synthetic data sets demonstrate the high performance and robustness of the proposed scheme.

This study aims to investigate the measurement of left ventricular flow propagation velocity, V p, using phase contrast magnetic resonance imaging and to assess the discrepancies resulting from inflow jet direction and individual left ventricular size. Three V p measuring techniques, namely non-adaptive (NA), adaptive positions (AP) and adaptive vectors (AV) method, were suggested and compared. We performed the comparison on nine healthy volunteers and nine post-infarct patients at four measurement positions, respectively, at one-third, one-half, two-thirds and the conventional 4 cm distances from the mitral valve leaflet into the left ventricle. We found that the V p measurement was affected by both the inflow jet direction and measurement positions. Both NA and AP methods overestimated V p, especially in dilated left ventricles, while the AV method showed the strongest correlation with the isovolumic relaxation myocardial strain rate (r = 0.53, p

Floods are frequent and widespread in Italy and pose a severe risk for the population. Local administrations commonly use flow propagation models to delineate the flood prone areas. These modeling approaches require a detail geo-environmental data knowledge, intensive calculation and long computational times. Conversely, statistical methods can be used to asses flood hazard over large areas, or to extend the flood hazard zonation to the portion of the river networks where hydraulic models have still not been applied or can be applied with difficulties. In this paper, we describe a statistical approach to prepare flood hazard maps for the whole of Italy. The proposed method is based on a multivariate machine learning algorithm calibrated using in input flood hazard maps delineated by the local authorities and terrain elevation data. The preliminary results obtained in several major Italian catchments indicate good performances of the statistical algorithm in matching the training data. Results are promising giving the possibility to obtain reliable delineations of flood prone areas obtained in the rest of the Italian territory.

Flow routing models are an essential tool for water systems planning and management. In the last few years, advances in modelling capability, enhanced data availability, and increasing computational power have made the use of large, process-based, flow-routing models more common. However, the computational burden of such models still prevents their systematic application for operational purposes. This paper presents an alternative, data-driven approach to the identification of a flow-routing model both in one-step-ahead prediction and simulation mode, and demonstrates it by application to the Red River network, in Northern Vietnam. In particular, MIMO time-invariant models for the network are considered, their parameters are estimated using subspace model identification techniques and their performance is assessed with respect to the available data. Results show that the non-linear process of flow propagation is accurately reproduced both in prediction and simulation using very low order models.

Objective: Diastolic dysfunction precedes systolic dysfunction during the development of myocardial ischemia. Detecting diastolic dysfunction during stress test for coronary artery disease (CAD) could improve diagnostic sensitivity of the test. Flow propagation velocity (FPV) derived from color M-mode Doppler has been proposed as a sensitive marker to detect diastolic dysfunction. Methods: The FPVs at baseline and at peak dobutamine infusion were measured using color M-mode Doppler during dobutamine stress echocardiography in 90 patients. The results are compared among the groups divided on the results of coronary angiography. Results: The FPV was similar at baseline among the groups. At peak dobutamine infusion, the FPV increased significantly in the non-CAD group (from 56 ± 19 cm/s to 66 ± 25 cm/s), whereas it failed to increase in the groups with CAD. As a result, the peak FPV was significantly lower in the groups with CAD than in the non-CAD group. Receiver operating characteristic analysis showed that the peak FPV and ΔFPV had good diagnostic property to detect CAD (the areas under the curves were 0.77 and 0.73, respectively). Adopting these FPV criteria, sensitivity of DSE was improved. Conclusion: FPV measurement during DSE detects ischemic left ventricular diastolic dysfunction. Adding the assessment of peak FPV to conventional DSE increases the sensitivity and the ability to reliably exclude CAD. (Echocardiography 2011;28:335-341)

Mitral regurgitation (MR) can affect left ventricular diastolic parameters because of interference with regurgitation flow. This study compared left ventricular diastolic parameters between patients with and without significant MR. The MR group included 57 consecutive patients with significant MR. Fifty-seven age-, sex- and Tei index-matched patients without significant MR were selected as the reference group. Baseline characteristics and Tei index and its components were comparable between the MR and reference groups. The MR group had higher left atrial volume index, transmitral E wave velocity (E), ratio of E to transmitral A wave velocity, early diastolic mitral annular velocity (Ea), E/Ea, and ratio of E to isovolumic relaxation flow propagation velocity (IRFPV) (p ≤ 0.025), and lower E-wave deceleration time (p = 0.019) and late diastolic mitral annular velocity (p < 0.001). However, the two groups had similar IRFPV (p = 0.844). In conclusion, MR apparently affects E and Ea, but not IRFPV. IRFPV could potentially be a reliable relaxation parameter in patients with significant MR, but further confirmation by invasive studies is needed.

Dike overtopping is an important issue in both scientific and practical aspects of sediment embankment erosion. This research is concerned with the validation of a one-dimensional numerical code applied to an unsteady two-phase flow over an initially trapezoidal-shaped sediment dike, including the transition from sub- to supercritical flows and the flow propagation over a steep slope. The approach is based on the shallow-water equations coupled with a sediment erosion code. The numerical results are compared with recent laboratory experiments, resulting in a reasonable prediction of the temporal free surface and bed evolution. The remaining model inaccuracies mainly originate from overflow initiation with extremely small flow depths, streamline curvature effects with the related underestimation of flowvelocities close to the sediment surface, and the changing saturation in the dike body not accounted for in the model. Despite these deficiencies, the computational model will be helpful, particularly in flood risk assessment and management.

The experimental procedure and test data on assessment of rates of air filtration flow are reported. Permeability of the test specimens differ by more than four orders in the range of linear filtration. The tests with core specimens under the gas pressures of 0.5, 1, 2, 5, 10 MPa established relationships between the gas propagation rate, gas pressure, structure and hydrodynamic characteristics of the specimens.

OBJECTIVE This study investigates the change in flow propagation velocity (FPV) in uremic patients who undergo regular hemodialysis (H/D). MATERIALS AND METHODS We studied 93 uremic patients (44 men and 49 women; 59 +/- 14-years-old) receiving regular hemodialysis. Patients were separated by baseline left ventricular ejection fraction (LVEF): 71 patients with LVEF > 50% (group 1), 13 patients with LVEF 35-50% (group 2), 7 patients with LVEF 50%, FPV after H/D was almost always lower, regardless of H/D amount. But there was different response in patients with baseline LVEF 50%.

In this article, we propose a framework for travel time prediction based on a time-discrete, mesoscopic traffic flow model, in which the measure of travel time is obtained as a link performance resulting from a dynamic network loading process. The spatiotemporal flow propagation on the road network is simulated incorporating the mesoscopic model and a linear link performance model, based on a travel time function. Acceleration levels are calculated explicitly, as a result of a fixed point problem. The traffic assignment to the network has been carried out through a completely new model, based on the Bee Colony Optimization (BCO) metaheuristics. In comparison with results of simulations carried out by using another mesoscopic model (DYNASMART), the travel times obtained with the proposed method appear more realistic. (C) 2015 Elsevier Ltd. All rights reserved.

To test the applicability of isovolumic relaxation flow propagation velocity (IRFPV) as an indicator of relaxation, 38 patients undergoing cardiac catheterization for chest pain were included. The time constant of isovolumic left ventricular (LV) pressure decline (tau) had a significant correlation with the LV end-diastolic pressure, the peak negative dp/dt, the LV end-diastolic dimension, the fractional shortening, the late diastolic transmitral flow velocity, the early and late diastolic mitral annular velocities, the rapid filling flow propagation velocity, and the natural logarithms of heart rate, ejection fraction, LV end-systolic dimension and IRFPV (r = -0.773, p0.001). IRFPV was selected as the major independent determinant of tau, explaining 46% of its variance. In prediction of tauor =42 ms, the sensitivity and specificity were 100% and 83% for IRFPVor =104 cm/s, 77% and 67% for the rapid filling flow propagation velocityor =50 cm/s, and 58% and 67% for the early diastolic mitral annular velocityor =8 cm/s, respectively. In conclusion, our data suggest that IRFPV could be a better marker of LV relaxation than other parameters, as the rapid filling flow propagation velocity or the early diastolic mitral annular velocity.

Background: The purpose of the present study was to establish the normal values of flow propagation velocity (FPV) in healthy children and examine the variables that affect FPV in clinical situations. Methods: Two hundred and thirty- five healthy children and adolescents were assessed (aged 0–22.6 years, mean age 7.4 ± 5.4 years; male, n = 142; female, n = 93). FPV was obtained from an apical four-chamber view and determined as the slope of aliasing velocity of early diastolic transmitral flow on the color M-mode using Aloka SSD-5500 with 5.0 MHz transducer. Aliasing velocity was set at 50–70% of the peak transmitral flow velocity. Peak transmitral flow velocities in early diastole (E) and during atrial contraction (A), and the ratio of early to late peak velocity (E/A) were obtained. Tei index was also measured for analysis of general left ventricular performance. Left ventricular mass index (LVMI) was obtained from conventional echo measurement. E, E/A, Tei index and LVMI were compared with FPV in healthy subjects. Results: FPV obtained from all subjects ranged from 23.7 to 96.0 cm/s (61.3 ± 13.6 cm/s). Normal value of FPV was less dependent on age, body size, heart rate and left ventricular dimension. In contrast, although there was no significant correlation between FPV and ejection fraction, statistically significant correlation was found between FPV, LVMI (P = 0.0008) and Tei index (P = 0.025). Conclusions: FPV is independent of age, body size and heart rate and is useful to assess left ventricular relaxation in children.

We propose a flow propagation algorithm (FlowPro) that finds the community surrounding a node in a complex network. In each iteration of the main process of FlowPro, the initial node propagates a flow that is shared among its neighbors. Each node is able to store, propagate to its neighbors, and return, part of the flow it receives to the initial node. When the algorithm converges, the flow stored in the nodes that belong to the community of the initial node, is generally higher than the flow stored in the rest of the graph nodes, thus the requested community emerges. The novelty of the proposed approach lies in the fact that FlowPro is local, allows to visualize the community and does not require the knowledge of the entire graph as most of the existing methods found in the literature. This makes possible the application of FlowPro in extremely large graphs or in cases where the entire graph is unknown like in most social networks.

OBJECTIVE We aimed to evaluate myocardial diastolic function in patients with beta-thalassemia major (beta-TM) using pulsed-tissue Doppler imaging (TDI) and flow propagation (VP), in relation to BNP levels. METHODS We enrolled 192 consecutive patients with beta-TM (88 men (25 +/- 6 years) and 104 women (26 +/- 6 years), with normal left ventricular (LV) systolic function. By TDI, diastolic myocardial velocities were sampled at the lateral section of the mitral annulus (Smv, Emv, Amv). From the apical four-chamber view diastolic transmitral flow velocities, including measures of E- and A-waves were performed. The propagation velocity of early flow into the LV cavity was measured by color M-mode Doppler. Plasma BNP levels were measured in all patients. RESULTS A nonlinear relationship was found between BNP levels and E/A ratio (beta coefficient for the second-order term = 1.4 +/- 0.4, P = 0.001). We also found a positive association of BNP levels with Amv (r = 0.28, P = 0.023), and a reverse with Smv (r =-0.59, P = 0.01) and Emv/Amv (r =-0.36, P = 0.019). Moreover, an inverse relationship was observed between BNP and Vp (r =-0.43, P = 0.012) levels. Finally, a strong positive linear relationship was found between E/Vp ratio and BNP levels (r = 0.76, P < 0.001). CONCLUSION A U-curved association of E/A ratio of transmitral Doppler velocity was revealed with BNP levels, while the tissue Doppler of the Emv/Amv of the mitral annulus movement showed a negative linear association with BNP levels.

Objective This study investigated the change in new diastolic indexes in patients with uremia who undergo regular hemodialysis (H/D). Methods We studied 81 patients with uremia (41 men and 40 women) receiving regular H/D. All patients were in sinus rhythm before H/D. They had normal left ventricular systolic performance without regional wall-motion abnormality. Three patients were excluded because of atrial fibrillation after H/D. Patients were separated by the amount of body fluid removed during H/D procedure: 30 patients with H/D amount less than 2 kg (group 1), 33 patients with H/D amount between 2 and 3 kg (group 2), and 18 patients with H/D amount larger than 3 kg (group 3). They received complete transthoracic echocardiographic examinations. Flow propagation velocity (FPV) was measured by color M-mode echocardiography in apical 4-chamber view. Mitral annulus Doppler tissue velocities (peak systolic [Sa], early diastolic [Ea], and late diastolic [Aa]) were measured from septal, lateral, inferior, and posterior walls. All these parameters were obtained immediately before and after H/D. Paired data were compared. Results In patients with removed fluid amount less than 2 kg (group 1), the change of all diastolic parameters showed insignificant change except FPV (peak mitral E, P = .14; peak mitral A, P = .916; FPV, P = .009; septal Sa, P = .173; septal Ea, P = .295; septal Aa, P = .649). In patients with H/D amount between 2 and 3 kg, the change of all diastolic parameters showed statistically significant difference except Sa (peak mitral E, P = .001; peak mitral A, P = .001; FPV, P = .001; Sa, P = .589; Ea, P = .001; Aa, P = .015). In patients with H/D amount larger than 3 kg, Sa still showed insignificant change. Ea, Aa, and FPV showed significant difference after H/D (peak mitral E, P = .001; peak mitral A, P = .035; FPV, P = .008; septal Sa, P = .777; septal Ea, P = .014; septal Aa, P = .048). Conclusion In patients with normal left ventricular systolic function, FPV was preload dependent. Diastolic phase mitral annulus Doppler tissue velocities (Ea and Aa) behaved differently according to the amount removed during H/D. They were preload independent when the amount removed during H/D was less than 2 kg. When the amount removed during H/D was larger than 2 kg, diastolic phase mitral annulus Doppler tissue velocities changed significantly. That is to say, diastolic phase mitral annulus Doppler tissue velocities were not totally preload independent. For systolic phase mitral annulus Doppler tissue velocity index (Sa), it was preload independent.

Using recorded flow and tissue Doppler, we evaluated the relation of peak velocity of early transmitral Doppler filling (E)/early diastolic velocity of the lateral mitral annulus (Ea) ratio and of E/flow propagation velocity (Vp) ratio to mean left atrial pressure in infants after surgery for congenital heart disease.Experimental design.Pediatric intensive care unit.Thirty-seven infants aged 4 (3-8) months.Patients underwent postoperative invasive hemodynamic monitoring with simultaneously obtained Doppler measurements.Values are expressed as median (25th-75th percentiles). Heart rate was 145 (135-157) beats/min. Left atrial pressure was 10 (8-12) mm Hg with E/Ea 16 (12-19) and E/Vp 1.9 (1.3-2.4). E/Ea and E/Vp ratios were higher in patients with left atrial pressure10 mm Hg (n = 18), than in patients with left atrial pressureor =10 mm Hg (n = 19) (E/Ea, 16 [15-25] vs. 12 [9-17], p = .01; E/Vp, 2.3 [1.9-2.8] vs. 1.4 [1-1.9]. respectively, p = .001). At a cutoff point of 15, E/Ea sensitivity for left atrial pressure10 mm Hg was 17 of 18 (94%) with specificity 13 of 18 (72%). At a cutoff point of 2, E/Vp sensitivity for left atrial pressure10 mm Hg was 15 of 18 (83%) with specificity 16 of 18 (89%). Areas under the receiver operating characteristic curves were 0.76 (E/Ea) and 0.83 (E/Vp).Doppler ratios might be considered as promising noninvasive tools for left atrial pressure evaluation in infants after cardiac surgery.

Background and objective: Color M-mode flow propagation velocity (Vp) was shown to be a preload-independent measure of diastolic function. To study the effects of an increase in afterload induced by isometric handgrip exercise on diastolic function assessment in patients with cardiomyopathy, we measured Vp and conventional Doppler indices at baseline and at 30% of predetermined maximum handgrip strength. Methods: Twenty-four patients with systolic dysfunction were divided into two groups: Group I comprising 12 patients with E/A 1. All the patients underwent measurement of Vp, E velocity, its deceleration time (DT), A velocity, isovolumic relaxation time (IVRT), and pulmonary atrial flow reversal velocity (PFR) at baseline and at 30% of predetermined maximum handgrip strength. Twelve healthy controls underwent these same measurements. Results: When comparing baseline to peak echocardiographic data, no significant changes were noted in Vp in any of the groups while a shift of pulsed Doppler indices of Group I toward a pattern closer to that of Group II was noted and a decrease in E velocity and E/A ratio with an increase in IVRT occurred in healthy controls. Conclusions: Color M-mode flow propagation velocity seems to be an afterload-independent measure of diastolic function in patients with moderate to severe cardiomyopathy while pulsed Doppler indices are more sensitive to loading conditions induced by isometric exercise.

Chronic exercise induces physiological enlargement of the left ventricle (‘athlete's heart’), but the effects of current and long-term exercise training on diastolic function have not been investigated. Echocardiography and Doppler imaging were used to assess left ventricular (LV) dimensions and indices of diastolic filling in 22 elite athletes at the end of their ‘off-season’ (baseline) and, subsequently, following 3 and 6 months of training. Twelve matched controls were also studied at baseline, 3 and 6 months. Compared to controls at baseline, athletes exhibited significantly higher LV mass (235.7 ± 7.1 g versus 178.1 ± 14.5 g, P < 0.01) and reduced flow propagation velocity (VP: 50.21 ± 1.7 versus 72.2 ± 3.6 cm s−1, P < 0.01), a measure of diastolic function. Three months of training further increased LV mass in athletes (253.2 ± 7.1 g; P < 0.01 versus baseline), and significantly increased their VP (66.7 ± 2.5 cm s−1; P < 0.05 versus baseline). These trends for increased mass and diastolic filling persisted following 6 months of training (LV mass 249.0 ± 8.7 g P < 0.05 versus baseline; VP 75.7 ± 3.0 cm s−1; P < 0.01 versus baseline, and P= 0.01 versus 3 months). This study suggests that following a period of relative inactivity the rate of ventricular relaxation during early diastole may be slowed in athletes who exhibit ventricular hypertrophy, whilst resumption of training increases the speed of ventricular relaxation in the presence of further hypertrophy of the left ventricle.

Pulsed wave tissue Doppler echocardiography (PW-TDE) and color M-mode are new Doppler methods for left ventricular (LV) diastolic function assessment. To date, few studies have compared the data obtained by these methods in the same series of patients and compared them to the current clinical reference method of detecting LV diastolic function.To determine the utility of PW-TDE and color M-mode parameters in the assessment of LV diastolic function in the typical patient population encountered in daily clinical practice and to compare their discriminating power.Early diastolic septal mitral annular velocity (Em) determined by PW-TDE and color M-mode flow propagation velocity (Vp) were measured in 86 male patients and compared to LV filling patterns obtained using standard Doppler indices. Values of Em0.08 m s(-1) and Vp0.5 m s(-1) were considered as markers of abnormal LV diastolic function.A value of Em0.08 m s(-1) distinguished mild to moderate LV diastolic dysfunction with higher sensitivity and specificity than Vp0.5 m s(-1) (96% and 87% vs. 73% and 84%, respectively). A comparison of receiver operating characteristic curves showed a significant difference for areas under the curve in favor of Em (P0.01). In a stepwise multiple logistic regression analysis, a pseudonormal filling pattern and an EF60% were identified as significant predictors of Vp false negative results (p0.05).Em appears to be superior to Vp in the detection of mild to moderate LV diastolic dysfunction. Vp failed to detect abnormal LV diastolic function in particular in patients with preserved LV systolic function and a pseudonormal filling pattern type.

We propose a method (CoViFlowPro) for the visualization of a community of a node based on the results of a flow propagation algorithm (FlowPro) [15]. FlowPro computes the community of a node in a network without the knowledge of the structure of the entire graph resulting at the same time to a metric that is related with the probability of a node belonging to the requested community. In this work, we use this metric to visualize the community of a node on the curve of the Archimedean spiral. The novelty of CoViFlowPro is the fact that the proposed community visualization method is local and it does not require the knowledge of the entire graph as most of the existing visualization methods from the literature. Moreover, it visualizes the community of a node taking into account the significance of the node membership.

Echocardiographic Doppler methods widely used in assessment of the severity of aortic regurgitation (AR) are considered sensitive and reliable. However, they all have limitations for quantitation of AR. The color M-mode Doppler flow propagation velocity (FPV) method has been shown to provide useful insights in the evaluation of left ventricular diastolic function and appears to be minimally affected with preload changes. Clinical data regarding the value of FPV in the determination of the significance of valvular insuffiencies are lacking. The purpose of this study was to evaluate the use of FPV in measurement of the severity of AR and to compare its reliability with angiography and other echocardiographic methods.Twenty-nine patients (13 male, 16 female) who had cardiac catheterization for various reasons before echocardiographic evaluation were included. The mean age was 53.6 +/- 13.4 years. At the time of cardiac catheterization, the degree of AR was assessed as mild in 10 patients, as moderate in 12, and as severe in 7. In all patients, FPV measurements of AR were obtained with color M-mode Doppler in the apical 5-chamber view. Regurgitation jet height and its ratio to left ventricular outflow obtained in the parasternal long axis with color flow Doppler, pressure half-time, and slope of AR obtained with continuous wave Doppler in apical 5-chamber view were other echocardiographic methods chosen for comparison.The mean values of FPV were 93.1 +/- 18.4 cm/s, 49.8 +/- 8.0 cm/s, and 31.7 +/- 4.9 cm/s in severe, moderate, and mild AR groups, respectively (P.001). Significant correlation was observed between angiographic grades, FPV, pressure half-time, slope, and jet height and ratio to left ventricular outflow (P.0001, r = 0.93; P.0001, r = -0.81; P.0001, r = 0.76; P.0001, r = 0.92, respectively).FPV is a simple, practical, and reliable method for the quantification of AR.

Background and Objective: Color M-mode flow propagation velocity (Vp) has been reported as a preload-independent measure of diastolic function. To study the effects of loading conditions on diastolic function assessment in patients on chronic hemodialysis, we measured Vp and conventional Doppler indices pre- and posthemodialysis. Methods: Twenty hemodialysis patients with normal systolic function underwent measurement of Vp, early filling velocity (E), its deceleration time (DT), atrial contraction velocity (A), isovolumic relaxation time (IVRT), and pulmonary atrial flow reversal velocity (PFR) pre- and posthemodialysis. Twelve healthy controls underwent these same measurements. Results: Hemodialysis patients had significantly slower Vp at baseline than normal controls, while E/A, DT, IVRT, and pulmonary flow reversal were not significantly different. E, IVRT, and PFR were affected by hemodialysis, while color M-mode flow propagation velocities, A, and DT were not. Conclusions: Color M-mode flow propagation velocity seems to be a preload-independent measure of diastolic function in chronic hemodialysis patients in whom isolated diastolic dysfunction appears prevalent.

Blood flow throughout the cardiovascular system is governed by the Navier-Stokes equations, a set of 4 coupled 4-dimensional (3 of space and 1 of time) partial differential equations. Although these are impossibly complex to solve analytically or even with the most powerful supercomputers, there are

Background — Accurate determination of pulmonary vascular resistance (PVR) is an important component in the evaluation and treatment of pediatric patients with pulmonary hypertension. We developed a novel technique, based on the concept of flow propagation, to estimate PVR noninvasively. The hypothesis is that changes in PVR cause changes in the velocity propagation (Vel prop ) within the main pulmonary artery and that Vel prop can be quantified using color M-mode imaging. Methods and Results — We tested the hypothesis using mathematical modeling, in vitro experiments, and preliminary clinical studies. The mathematical model showed that pressure and velocity tracings are closely correlated in time and that 6 to 18 ms time resolution was needed to resolve propagation times within typical main pulmonary artery lengths (2 to 5 cm). The in vitro experiments demonstrated that it was feasible to use color M-mode to measure Vel prop and that Vel prop correlated well with downstream resistance [y=(−1.01x)+22.77; R =0.96]. The method was then evaluated on patients undergoing acute pulmonary reactivity testing (n=22 measurements). Good correlation between Vel prop and PVR was found [y=(−1.71x)+26.0; R =0.90; SEE=2.41]. Conclusion — This newly developed method promises to be useful in the noninvasive evaluation of adults and children with pulmonary hypertension.

Diagnosis of diastolic heart failure remains difficult in clinical practice. Noninvasive assessment of the flow field within the left ventricle (LV) using color M-mode Doppler(CMD) echocardiography provides a potential technique that can differentiate between the normal and diseased heart. The aim of this study is to evaluate the behavior of the flow propagation velocity (vp), measured using CMD echocardiography for varying settings of physiologic determinants of diastolic function. A hydraulic model of LV filling was constructed. CMD images of LV filling are simulated in the hydraulic model for varying filling pressure (5–30 mmHg), compliance (0.45–1.35 mL/mmHg), and relaxation (45–90 ms). In a 2D axisymmetrical numerical model analogue simulations were done. The interaction between vp and LV diastolic variables is studied in a numerical model and compared to corresponding hydraulic model results. Overall a good agreement is found. vp increases with increasing left atrial filling pressure and decreases with increasing τ. A decrease in compliance augments vp in the region of the LV base but decreases vp due to stagnation of the vortex at the mid level of the LV.

This paper formulates a discrete-time, link-based dynamic user-optimal route choice problem using the variational inequality approach. The proposed model complies with the dynamic user-optimal equilibrium condition in which for each origin-destination pair, the actual travel time experienced by travelers departing during the same interval is equal and minimal. A nested diagonalization procedure is then proposed and demonstrated with a numerical example.

Flow propagation velocity is a new color Doppler M-mode measurement of left ventricular filling characteristics. This study was designed to establish normal values for this measurement in healthy individuals and to compare these findings with pulsed Doppler transmitral velocities. Complete M-mode, two-dimensional, and Doppler echocardiographic studies were performed on 64 volunteers between 21 and 79 years of age. Significant negative correlations (p < 0.001) with age were noted for flow propagation velocity (r = -0.59), peak early diastolic filling velocity (r = -0.65), and peak early diastolic filling/peak atrial filling ratio (r = -0.80). Positive correlations (p < 0.001) with age were observed for peak atrial filling velocity (r = 0.50) and atrial filling velocity integral (r = 0.71). Flow propagation velocity decreased by 44% between the youngest and oldest age groups. We conclude that flow propagation velocity is influenced by age and that it compares favorably with transmitral Doppler indices of left ventricular filling in this regard. These age-related alterations are present in healthy individuals, in the absence of any apparent cardiovascular disease.

In this paper, we propose a flow propagation algorithm (FlowPro) that finds the community of a node in a complex network. The novelty of the proposed approach is the fact that FlowPro is local and it does not require the knowledge of the entire graph as most of the existing methods from literature. This makes possible the application of FlowPro in extremely large graphs or in cases where the entire graph is unknown like in most social networks. In addition, it simply compute the community of exactly one node, that is the major issue in most social network based applications. Experimental results and comparisons with other methods from the literature are presented for a variety of benchmark graphs with known community structure, derived by varying a number of graph parameters and real dataset graphs.

The existence of a lipid factor that either causes faulty lipid metabolism or directly contributes to the emergence of a biophysical shunt in neuronal membrane ionic flow propagation is proposed. The neuronal membrane contains a remarkable amount of phospholipids, glycolipids and cholesterol. It is assumed that, under certain unfavorable intrinsic states, the plasma membrane's lipid order and composition and, consequently, its cholesterol-to-phospholipid ratio, may change. This, in turn, may significantly modify membrane fluidity, altering the essential physical properties in the affected portions of the membrane and causing a disarray in the adjacent ion channels, leading to the establishment of a biophysical shunt in a loop-like operation, forming the basis for a variety of mental disorders. The present model offers a diet-induced lipid correction for the relief of psychopathological problems.

Cell-based dynamic equilibrium models are one class of dynamic traffic assignment (DTA) models that can capture equilibrium conditions and realistic traffic dynamics, such as queue spillback, queue formulation, and queue dissipation. However, compared with point-queue DTA models or DTA models using whole-link delay models for flow propagation, cell-based equilibrium models are often more computational demanding. This may raise issues for actual applications, in particular, for the implementation for real-time traffic control and route guidance applications, because the solution must be obtained quickly. Moreover, recent cell-based dynamic equilibrium models tend to capture more realistic travel behavior and traffic dynamics but this made the resulting models even more complicated and more difficult to solve for optimal solutions. Hence, this article aims at reviewing the recent development of cell-based dynamic equilibrium models, the formulation approaches, solution methods used, and the components of these models so as to point out the implementation issues of the latest cell-based dynamic equilibrium model with the consideration supply stochasticity for traffic control and route guidance applications as well as some gaps for future research directions.

Energy distributions of high frequency linear wave fields are often modelled in terms of flow or transport equations with ray dynamics given by a Hamiltonian vector field in phase space. Applications arise in underwater and room acoustics, vibro-acoustics, seismology, electromagnetics, and quantum mechanics. Related flow problems based on general conservation laws are used, for example, in weather forecasting or molecular dynamics simulations. Solutions to these flow equations are often large scale, complex and high-dimensional, leading to formidable challenges for numerical approximation methods. This paper presents an efficient and widely applicable method, called discrete flow mapping, for solving such problems on triangulated surfaces. An application in structural dynamics - determining the vibro-acoustic response of a cast aluminium car body component - is presented., Comment: 12 pages, 6 figures

Aims: Early diastolic mitral annular velocity (e') obtained by tissue Doppler imaging (TDI) is widely used to evaluate left ventricular (LV) diastolic function based on the assumption that it reflects myocardial relaxation in the long-axis direction. In this study, we aimed to determine whether or not e' truly reflects early diastolic longitudinal myocardial relaxation, and which is the most useful for evaluating LV diastolic function among e' measured at the interventricular-septal annulus (IS-e'), that measured at the lateral annulus (LW-e') or their mean value (M-e'). Methods and results: IS-e', LW-e', and M-e' were measured using colour TDI in 15 patients with hypertrophic cardiomyopathy, 13 patients with hypertension and 19 control subjects. Using two-dimensional speckle tracking imaging, early diastolic myocardial strain rates (SR_[E]) were measured for the IS (IS-SR_[E]), LW(LW-SR_[E]) and entire LV myocardium (G-SR_[E]). IS-e' was excellently correlated with IS-SR_[E] (r = 0.90, P < 0.001); the correlation was better than that between LW-e' and LW-SR_[E] (r = 0.75, P < 0.001). IS-e' and M-e' were well correlated with G-SR_[E] (r = 0.88, P < 0.001 and r = 0.86, P < 0.001, respectively) and with LV early diastolic flow propagation velocity (r = 0.77, P < 0.001 and r = 0.78, P < 0.001, respectively). The correlations of LW-e' to G-SR_[E] (r = 0.80, P < 0.001) and flow propagation velocity (r = 0.75, P < 0.001) did not reach this level. Conclusion: IS-e' well reflected LV longitudinal myocardial relaxation and LV diastolic function, and was found to be more useful in evaluating LV diastolic function than LW-e'.

To assess the feasibility of left atrial flow propagation velocity (LAFPV) measurement and to evaluate the influence of preload alterations on this new parameter of left atrial (LA) reservoir function as compared to conventional echocardiographic indices. 30 healthy volunteers (26 ± 5 years, 20 males) underwent echocardiographic examination at rest, during passive leg lifting and after sublingual administration of nitroglycerine with subsequent Valsalva maneuver. LA reservoir function was assessed by conventional indices including LA expansion index, peak velocity and velocity-time integral of pulmonary venous systolic flow. As well, LAFPV was measured by color M-mode in an apical 4-chamber view as the slope of the transatrial flow wave during LA reservoir phase. LAFPV measurement was feasible in 25 subjects (83%). All conventional parameters of LA reservoir function were significantly altered from resting values by both load-modifying conditions. However, LAPFV was not significantly altered by such maneuvers (228 ± 28 cm s−1 at rest vs. 238 ± 33 cm s−1 during leg lifting, P = NS, vs. 218 ± 38 cm s−1 after nitroglycerin with Valsalva maneuver, P = NS vs. rest, P

This chapter deals with the mathematical models simulating transportation supply systems. In broad terms a transportation supply model can be defined as a model, or rather a system of models, simulating the performances and the flows resulting from users’ demand and the technical and organizational aspects of the physical transportation supply. The general structure of a supply model is depicted in Fig. 2.1.1, where several elements (or sub-models) can be distinguished. The graph defines the topology of the connections allowed by the transportation system under study, while the network loading or flow propagation model defines the relationship among path and link flows. The link performance model expresses for each element (link) the relationships between performances, physical and functional characteristics, and flow of users. The impact model simulates the main external impacts of the supply system. Finally, the path performance model defines the relationship between the performances of single elements (links) and those of a whole trip (path) between any origin-destination pair.

Transmitral E wave velocity was reported to be positively related to left ventricular (LV) filling pressure and negatively related to LV relaxation constant, and isovolumic relaxation flow propagation velocity (IRFPV) was proven recently to be negatively related to LV relaxation constant and independent of preload alterations. Therefore, the combination index, E/IRFPV, may eliminate the influence of LV relaxation and bring the LV filling pressure into focus. However, it is unknown whether E/IRFPV is a useful index in prediction of LV filling pressure. The aim of this study is to evaluate the correlation between E/IRFPV and LV end-diastolic pressure (LVEDP). Forty-three patients with suspected coronary artery disease who underwent a Doppler echocardiographic study and cardiac catheterization were included. LVEDP was determined by a micromanometer-tipped catheter. In a univariate analysis, LVEDP had a positive correlation with left atrial dimension, LV end-diastolic dimension, LV end-systolic dimension, the ratio of E to E wave propagation velocity (EPV) (r = 0.408, p = 0.007), the ratio of E to early diastolic mitral annular velocity (Ea) (r = 0.439, p = 0.003) and E/IRFPV (r = 0.686, p0.001). It had a negative correlation with diastolic blood pressure, E wave deceleration time, LV ejection fraction, EPV, Ea and IRFPV. After stepwise multiple linear regression analysis, only the E/IRFPV was the independent predictor of LVEDP (beta = 0.667, p0.001). In conclusion, E/IRFPV is a useful parameter in prediction of LVEDP.