Comparison of in-phase and opposed-phase GRE and conventional SE MR pulse sequences in T1-weighted imaging of liver lesions

PURPOSE: Our goal was to compare in-phase (IP) and opposed-phase (OP) GRE and conventional SE sequences in T1-weighted (T1-W) imaging of the liver and to evaluate chemical shift GRE imaging in characterizing liver/lesions for fat content. METHOD: IP and OP T1-W GRE with fast low angle shot (FLASH) technique and T1-W SE sequences were compared in 162 patients at 1.0 T. Chemical shift GRE imaging was used to characterize lesions with fat content. Two hundred sixteen lesions were analyzed in three groups of liver: (a) "normal" liver (n = 74 with 110 lesions); (b) cirrhotic liver (n = 76 with 85 lesions); and (c) fatty liver (n = 12 with 21 lesions). Liver/lesion contrast and liver/lesion contrast-to-noise ratio were assessed for lesion detectability. The percentage of signal intensity variation (SIV) between IP and OP images was used to characterize lesions for fat content. RESULTS: The OP GRE sequence had significantly higher contrast for normal and cirrhotic livers (p < 0.001), and the IP GRE sequence had significantly higher contrast and contrast-to-noise ratio for fatty liver (p < 0.001). There were no significant differences between OP, IP, and T1-W SE imaging in cirrhotic cases for contrast-to-noise ratio (p < 0.28). Chemical shift imaging detected fat in 21 lesions (9.7%, mean SIV, 191.1%) (sensitivity and specificity 100% when compared with fine needle aspiration cytology). CONCLUSION: OP GRE sequences could replace conventional SE sequences in T1-W imaging in nonfatty livers, whereas in fatty livers, T1-W SE sequences could be obviated, but both OP and IP sequences are necessary. Chemical shift imaging (OP and IP) can be used to accurately characterize lesions for fat content.     

Fault detection using interval LPV models in an open-flow canal

This paper proposes a new method of fault detection using Linear Parameter Varying (LPV) interval models and its application to an open-flow canal. The use of such models is motivated because the parameters and transport delay in the canal transfer function model vary with the operating point. LPV models allow to consider these variations by characterizing the parameters/delay variation law with the operating point while intervals are used to bound the parameter/delay uncertainty. Additionally, a LPV parameter estimation algorithm that allows to estimate parameter/delay uncertainty intervals is also proposed. As an application case study, an open-flow canal system based on the Lunax dam-gallery system located in France is used to show the effectiveness of the proposed method to detect faults. The satisfactory results obtained allow to assess the effectiveness of the proposed approach.     

State estimation and decoupling of unknown inputs in uncertain LPV systems using interval observers

This paper proposes a linear parameter varying (LPV) interval observer for state estimation and unknown inputs decoupling in uncertain continuous-time LPV systems. Two different problems are considered and solved: (1) the evaluation of the set of admissible values for the state at each instant of time; and (2) the unknown input observation, i.e. the design of the observer in such a way that some information about the nature of the unknown inputs affecting the system can be obtained. In both cases, analysis and design conditions, which rely on solving linear matrix inequalities (LMIs), are provided. The effectiveness and appeal of the proposed method is demonstrated using an illustrative application to a two-joint planar robotic manipulator.     

Sensor fault diagnosis of singular delayed LPV systems with inexact parameters: an uncertain system approach

In this paper, sensor fault diagnosis of a singular delayed linear parameter varying (LPV) system is considered. In the considered system, the model matrices are dependent on some parameters which are real-time measurable. The case of inexact parameter measurements is considered which is close to real situations. Fault diagnosis in this system is achieved via fault estimation. For this purpose, an augmented system is created by including sensor faults as additional system states. Then, an unknown input observer (UIO) is designed which estimates both the system states and the faults in the presence of measurement noise, disturbances and uncertainty induced by inexact measured parameters. Error dynamics and the original system constitute an uncertain system due to inconsistencies between real and measured values of the parameters. Then, the robust estimation of the system states and the faults are achieved with H_∞ performance and formulated with a set of linear matrix inequalities (LMIs). The designed UIO is also applicable for fault diagnosis of singular delayed LPV systems with unmeasurable scheduling variables. The efficiency of the proposed approach is illustrated with an example.     

PLIO: a generic tool for real-time operational predictive optimal control of water networks

This paper presents a generic tool, named PLIO, that allows to implement the real-time operational control of water networks. Control strategies are generated using predictive optimal control techniques. This tool allows the flow management in a large water supply and distribution system including reservoirs, open-flow channels for water transport, water treatment plants, pressurized water pipe networks, tanks, flow/pressure control elements and a telemetry/telecontrol system. Predictive optimal control is used to generate flow control strategies from the sources to the consumer areas to meet future demands with appropriate pressure levels, optimizing operational goals such as network safety volumes and flow control stability. PLIO allows to build the network model graphically and then to automatically generate the model equations used by the predictive optimal controller. Additionally, PLIO can work off-line (in simulation) and on-line (in real-time mode). The case study of Santiago-Chile is presented to exemplify the control results obtained using PLIO off-line (in simulation).     

Understanding trust in privacy-aware video surveillance systems

Recent advances in pervasive video surveillance systems pave the way for a comprehensive surveillance of every aspect of our lives, hence, leading us to a state of dataveillance. Computerized and interconnected systems of cameras could be used to profile, track and monitor individuals for the sake of security. Notwithstanding, these systems clearly interfere with the fundamental right of the individuals to privacy. Most literature on privacy in video surveillance systems concentrates on the goal of detecting faces and other regions of interest and in proposing different methods to protect them. However, the trustworthiness of those systems and, by extension, of the privacy they provide are mostly neglected. In this article, we define the concept of trustworthy privacy-aware video surveillance system. Moreover, we assess the techniques proposed in the literature according to their suitability for such a video surveillance system. Finally, we describe the properties that a deployment of a trustworthy video surveillance system must fulfill.     

Solubility Limit and Anisotropy Analysis of Mg Doping in Melt Textured YBa2(Cu1−x Mg x )3O7−δ

Strong signatures of Mg substitution in Yba ₂ (Cu _1–x Mg _x ) ₃ O _7– have been obtained from single domain samples prepared by top seeding using YBa ₂ Cu ₃ O _7– + 30%wt Y ₂ BaCuO ₅ +X%wt MgO mixtures. A drastic decrease of the superconducting transition temperature with increasing X has been obtained reaching values of T _c 40 K for X=16.7. The T _c (x) dependence and thermogravimetric results suggest that Mg atoms substitute Cu(2) sites and that a solubility limit exists. Angular dependent magne-toresistance measurements have been used to determine the anisotropy of YBa ₂ (Cu _1–x Mg _x ) ₃ O _7– samples. These results are discussed on the basis of the recent controversy results reported for Zn-doped samples.     

Landscape fragmentation caused by the transport network in Navarra (Spain): Two-scale analysis and landscape integration assessment

Landscape fragmentation caused by the main transport infrastructure network in Navarra (north of Spain) is analysed on both regional and local scales. Regional scale analysis identifies the overloaded zones (cloverleaves and corridors) and the territorial imbalance due to transportation infrastructures. In order to achieve an holistic approach, this information could be compared to other fragmentation-related regional activities. The study of the fragmentation caused by the two northern dual carriageways is carried out at a local scale, analysing the surrounding landscape, the potential permeability and the road-kill rates of medium-sized terrestrial wildlife. The black spots and the funnel effect sites are identified. As both regional and local scales are complementary, the two-scale analysis could improve landscape management. Finally, it is concluded that visual landscape study does not guarantee a functional integration.     

Nanostructure formation enhances the activity of LPS-neutralizing peptides

Peptides that interact with lipopolysaccharide (LPS) can provide the basis for the development of new antisepsis agents. In this work, several LPS-neutralizing acyl peptides derived from LALF, BPI, and SAP were prepared, structurally characterized, and biologically evaluated. In all cases, peptides with long acyl chains showed greater LPS-neutralizing activities than the original acetylated peptides. Structural analysis of these peptides revealed that N-acylation with long acyl chains promotes the formation of micellar or fibril-like nanostructures, thus proving a correlation between anti-LPS activity and nanostructure formation. The results of this study provide useful structural insight for the future design of new acyl peptides that strongly bind LPS and therefore act as antisepsis drugs. Furthermore, this nanostructure-biological activity correlation can be translated into other therapeutic areas.     

Nanostructural control in solution-derived epitaxial Ce(1-x)Gd(x)O(2-y) films

A novel mechanism based on aliovalent doping, allowing fine tuning of the nanostructure and surface topography of solution-derived ceria films, is reported. While under reducing atmospheric conditions, non-doped ceria films are inherently polycrystalline due to an interstitial amorphous Ce(2)C(3) phase that inhibits grain growth, a high quality epitaxial film can be achieved simply by doping with Gd(3+) cations. Gd(3+) [Formula: see text] Ce(4+) substitutions within the lattice are accompanied by charge-compensating oxygen vacancies throughout the volume of the crystallites acting as an efficient vehicle to reduce the barrier for grain boundary motion caused by interstitial Ce(2)C(3). In this way, the original nanostructure is self-purified by pushing the amorphous Ce(2)C(3) phase towards the free surface of the film. Once a full epitaxial cube-on-cube oriented ceria film is obtained, its surface morphology is dictated by the interplay between faceting on low energy {110} and/or {111} pyramidal planes and truncation of those pyramids by (001) ones. The development of the latter requires the suppression of their polar character which is thought to be achieved by charge compensation between the dopand and oxygen along [Formula: see text] directions.