Role of surgical therapy in the treatment of refractory ascites

In 5-10% of cases ascites is not controlled by medical therapy and is defined refractory. These patients may be submitted to one of the four following surgical options: portal-systemic shunt, peritoneo-venous shunt, transjugular intrahepatic portal-systemic shunt, orthotopic liver transplantation. Although the portal-systemic shunt is efficient in clearing ascites, it does not improve the survival, which depends on liver function, and it is complicated by an important incidence of encephalopathy. Since the patients with refractory ascites and good hepatic risk are not usually many, it is possible to understand why derivative surgery has been disappointing with this indication. Although the peritoneo-venous shunt is associated with a significant rate of valve obstruction, it is an easy, effective and not expensive treatment. So, till now, it has been considered the first choice procedure of refractory ascites, if any situations, determinating the onset of postoperative complications, are not present. Recently a new method has been introduced in the therapy of portal hypertension, the transjugular intrahepatic portal-systemic shunt. This is a bloodless portal-systemic derivation and so it has caused great enthusiasm even if the available data are insufficient to give a definitive opinion on its role in management of ascites. Certainly the liver transplantation, which presents the great advantage to treat both the cirrhosis and its complications, seems to be the most rational therapy for these patients. However, at least for this moment, the well-known absence of organ donors makes still actual the palliative surgical measures.     

An approach and an Eclipse-based environment for enhancing the navigation structure of Web sites

This paper presents an approach based on information retrieval and clustering techniques for automatically enhancing the navigation structure of a Web site for improving navigability. The approach increments the set of navigation links provided in each page of the site with a semantic navigation map, i.e., a set of links enabling navigating from a given page to other pages of the site showing similar or related content. The approach uses Latent Semantic Indexing to compute a dissimilarity measure between the pages of the site and a graph-theoretic clustering algorithm to group pages showing similar or related content according to the calculated dissimilarity measure. AJAX code is finally used to extend each Web page with an associated semantic navigation map. The paper also presents a prototype of a tool developed to support the approach and the results from a case study conducted to assess the validity and feasibility of the proposal.     

Peer-assisted content distribution on a budget

In this paper, we propose a general framework and present a prototype implementation of peer-assisted content delivery application. Our system – called Cyclops – dynamically adjusts the bandwidth consumed by content servers (which represents the bulk of content delivery costs) to feed a set of swarming clients, based on a feedback signal that gauges the real-time health of the swarm. Our extensive evaluation of Cyclops in a variety of settings – including controlled PlanetLab and live Internet experiments involving thousands of users – shows a significant reduction in content distribution costs when compared to existing swarming solutions, with a minor impact on the content delivery times.     

Advantages of continuous hyperpolarized arrest with pinacidil over St. Thomas'' Hospital solution during prolonged ischemia

vlf-1 is a baculovirus gene that regulates very late gene expression (J. R. McLachlin and L. K. Miller, J. Virol., 68, 7746-7756, 1994) and also plays a crucial role in the replication of the budded form of Autographa californica nuclear polyhedrosis virus (AcMNPV) (S. Yang and L. K. Miller, "Expression and mutational analysis of the baculovirus very late factor 1 (vlf-1) gene." Virology, 245, 99-109, 1998). To examine the influence of vlf-1 expression on baculovirus infection, we constructed recombinant viruses that expressed only low levels of VLF-1 and recombinants with vlf-1 under the control of different promoters. Viruses with mutant alleles of vlf-1 that produced low levels of VLF-1 replicated the budded form of the virus normally but produced no occlusion bodies. Thus, a higher concentration of VLF-1 was needed to activate very late gene expression than was needed to support budded virus production. By altering the level and/or timing of vlf-1 expression, the timing of polyhedrin gene (polh) expression, which normally occurs very late in infection, could be advanced or delayed. Early overexpression of vlf-1 increased the level of expression from the polh promoter but caused premature cellular disintegration. The data indicate that VLF-1 is the limiting factor in very late gene expression and that the level of VLF-1 controls the onset of occlusion.     

Eu Atomic Motion in EuSr2Cu3O7−δ and EuBa2Cu3O7−δ: A Comparative Mössbauer Study

We present a comparative Mössbauer study of the ¹⁵¹Eu motions in the nonsuperconducting and superconducting cuprates EuSr₂Cu₃O_7?δ (ESCO) and EuBa₂Cu₃O_7?δ (EBCO), respectively, with the aim of investigating atomic-motion anharmonicities in these materials. In this study, a comparison with the results of a similar analysis of powdered samples of EBCO having oriented grains is also performed. We show that the Eu ion in ESCO, as well as in the common EBCO cuprates, does not move in a parabolic potential, but in a potential with a flat bottom. Moreover, for ESCO the flat part is about 1.5 times larger than for EBCO.     

A method for selecting macro-scale structures with axially loaded members

This paper presents a method to support the selection of lightweight large-scale structures. The method enables the ranking of alternative structural forms, whose axially loaded members can resist to either instability failure or material yield. Unlike previous approaches for concept design, this work models buckling failure to assess the interaction between the choice of a structural form and the choice of the cross-section shapes of its constituents. Shape transformers and scaling factors are introduced to characterize the structural efficiency of alternative cross-sectional shapes. Such parameters are dimensionless and enable to measure the shape efficiency without specifying the details of the cross-section geometry. The approach eases optimization at the concept design stage and it permits to assess how the selection of the member cross-sections impacts the lightweight potential of the structural topology. The model is used to construct charts for optimizing and selecting alternative forms. The method is applied in an industrial setting in order to compare three different structural concepts for a particular design application. The case study identified the potential performance of three structural forms and gave insight into the selection of the parameters that most influence structural performance.     

Multi-feature based automatic recognition of ship targets in ISAR

This paper deals with the problem of non-cooperative target recognition. Specifically, the aim is the automatic recognition of ship targets from inverse synthetic aperture radar (ISAR) images. For this purpose a new two-step multi-feature based technique is proposed; this technique uses a number of features extracted from the ship radar image and matches these features with those extracted from the images obtained by properly projecting the target models of the classification library. Both cases of a priori known or unknown ship aspect angles are considered: the knowledge of the ship aspect (as available from tracking data) allows the selection of the candidate models on the basis of the matching between the ship and the model length, thus resulting in a performance improvement. Moreover, both single- and multi-frame-based processing techniques are proposed in order to assess the performance improvement achievable when an increasing number of ISAR images are involved in the decision; the fusion strategy adopted for the exploitation of the information from the multiple images is also described. The performance of the overall proposed technique is deeply investigated against simulated data. Results of its application to a set of live ISAR images of a ship target are also provided showing the effectiveness of the proposed approach.     

Benchmarking parallel processing platforms: an applicationsperspective

Given the increased availability of general purpose parallel computers two issues arise: One needs to compare the performance of the different available platforms using realistic examples, and it is necessary to write application software that can be ported easily in order to take advantage of different platforms. The authors address these issues from an applications point of view. They are interested in the use of general purpose parallel computers for simulation tasks needed during the design of very large scale integrated (VLSI) circuits. They characterize the simulation task as a useful benchmark and introduce a high level process view of parallel simulation that is helpful for deriving portable parallel programs. Details of the partitioning strategy and the simulation algorithm used in the application are given. They discuss their implementation on different parallel machines and give statistics of various experiments     

A new model for calculating the input impedance of coax-fedcircular microstrip antennas with and without air gaps

A model is presented for calculating the input impedance of a probe-fed circular antenna with and without air gaps between the substrate and the ground plane. It is based on the cavity method, the dynamic permittivity constant (to take into account the influence of the fringing field at the edge of radiating element), and the resonant parallel R-L-C circuit with an inductive reactance. Numerical results are shown to agree well with experimental ones. The model is well suited for computer-aided design