Myocardial imaging with technetium-99m-tetrofosmin: comparison of one-day and two-day protocols

There is no evidence of myocardial redistribution after tetrofosmin injection, therefore, two separate injections are needed to differentiate scar from ischemia with this tracer. The injections can be given on the same day (one-day protocol) or on separate days (two-day protocol). As part of a Phase II clinical study, a one-day protocol was compared with a two-day protocol. METHODS: Fifty-five patients with suspected coronary artery disease were studied according to the following protocol: on the first day at rest, anterior, left lateral, left anterior oblique 40 degrees and 70 degrees images were acquired 30 min after injection of 8 mCi of tetrofosmin for 5 min each. Two days later, exercise and rest images were acquired on the same day. At peak exercise, 8 mCi of tetrofosmin were injected and 30 min later the same four standard planar images were recorded as on Day one. Four hours after the exercise injection, 24 mCi of tetrofosmin were injected at rest and imaging was repeated 30 min later. Qualitative comparisons between the one- and two-day protocols were performed in 50 patients in whom all data were available following blinded evaluation of images by three readers. RESULTS: All three readers reported identical results for the 26 patients. A difference in extent or location between the observers was found in seven patients, differences between normal and abnormal in eight patients, while discrepancies between ischemia and necrosis were noted in four patients. In five patients, an ischemic area was found according to the one-day protocol, but according to the data of the two-day protocol, this area was judged to be necrotic. One observer reported the opposite in one patient. These discrepancies between the reversibility of defects were restricted to the inferior wall. Comparison with 201Tl data showed no systematic pattern of variation. CONCLUSION: Tetrofosmin can be used in a one-day protocol. However, in planar imaging, the inferior wall should be reported with caution.     

Temperature Oscillation Calorimetry: Robustness analysis of different algorithms for the evaluation of the heat transfer coefficient

Applicability of different temperature oscillation calorimetry algorithms, previously proposed in the literature, for the evaluation of the heat transfer coefficient during the course of the reaction, is analysed by referring to the experimental data from a methyl methacrylate polymerisation reactor.Results are coincident in the nominal case (no errors on data), while differences appear in the elaboration of real data. The effect of uncertainty in the experimental data has been simulated in terms of error on the amplitude and on the phase of reactor and jacket temperature profiles.This approach allows to indicate algorithms having the best robustness properties and to give an explanation of phase errors in terms of a lumped parameter which accounts for different phenomena, not included in the basic hypotheses of the method. Based on this observation, a procedure to eliminate this source of errors from experimental data is proposed for the more general algorithm presented to handle oscillating temperature profiles generated by different techniques.     

A Web‐based Open‐source Geoinformation Tool for Regional Water Resources Assessment

Water Resources Management - To reduce the impact of droughts and increase the resilience of regional water systems, various competing demands, such as hydropower, supply, irrigation and river...     

THROO: a Tracked Hybrid Rover to Overpass Obstacles

In this paper, the design, simulation and experimental tests are presented for THROO: a Tracked Hybrid Rover, which has been developed to Overpass Obstacles. The proposed mobile robot has 3-DOFs and it is capable of straight motion, turning ability and two operations, namely rover-like motion with tracks on flat terrain and walking-like motion with track and legs to overpass obstacles to move on uneven terrain. The leg mechanism is composed of a four-bar linkage, which has been synthesized according to the desired features. In particular, the Burmester problem, which aims at finding the geometric parameters of a four-bar linkage required for a prescribed set of finitely separated poses are solved for the case understudy. Dynamic simulations have been carried out and a prototype has been built. The proposed results show the hybrid rover ability to overpass obstacles, for which size is comparable or greater than the track high.     

Feeding response of Ips paraconfusus to phloem and phloem metabolites of Heterobasidion annosum-inoculated ponderosa pine,Pinus ponderosa

In studies of feeding by the bark beetle, Ips paraconfusus, two pine stilbenes (pinosylvin and pinosylvin methyl ether), ferulic acid glucoside, and enantiomers of the four most common sugars present in ponderosa pine phloem (sucrose, glucose, fructose, and raffinose) did not stimulate or reduce male feeding when assayed on wet -cellulose with or without stimulatory phloem extractives present. When allowed to feed on wet -cellulose containing sequential extracts (hexane, methanol, and water) of ponderosa pine phloem, methanol and water extractives stimulated feeding, but hexane extractives did not. Males confined in wet -cellulose containing aqueous or organic extracts of culture broths derived from phloem tissue and containing the root pathogen, Heterobasidion annosum, ingested less substrate than beetles confined to control preparations. In an assay using logs from uninoculated ponderosa pines, the mean lengths of phloem in the digestive tracts increased as time spent feeding increased. Males confined to the phloem of basal logs cut from ponderosa pines artificially inoculated with H. annosum ingested significantly less phloem than beetles in logs cut from trees that were (combined) mock-inoculated or uninoculated and did not contain the pathogen. However, individual pathogen-containing treatments were not significantly different from uninoculated controls. It was concluded that altered feeding rates are not a major factor which may explain why diseased ponderosa pines are colonized by I. paraconfusus.     

On sets of numbers accepted by P/T systems composed by join

Recently, some studies linked the computational power of abstract computing systems based on multiset rewriting to models of Petri nets and the computation power of these nets to their topology. In turn, the computational power of these abstract computing devices can be understood by just looking at their topology, that is, information flow.Here we continue this line of research by introducing J languages and proving that they can be accepted by place/transition systems whose underlying net is composed only by join. Moreover, we study how J languages relate to other families of formal languages.     

Minimum-delay schedules in layered networks

Summary In this paper, we consider the following problem: given a layered network including a set of messages, each of which must be transmitted from a source to a sink node, what is the sequence of moves from one node to another which minimizes the total completion time? We first show that the general problem is NP-complete for both fixed and variable path routing (thus the scheduling problem for more realistic networks with cycles must be considered computationally intractable). We then consider several restrictions which admit polynomia time algorithms.Most of this work was done while this author was at the Department of Mathematics, University of Rome La Sapienza     

Simflowny: A general-purpose platform for the management of physical models and simulation problems

Simflowny is a software platform which aims to formalize the main elements of a simulation flow. It allows users to manage (i) formal representations of physical models based on Initial Value Problems (hyperbolic, parabolic and mixed-type partial differential equations), (ii) simulation problems based on such models, and (iii) discretization schemes to translate the problem to a finite mesh. Additionally, Simflowny generates automatically code for general-purpose simulation frameworks. This paper first presents an introductory example of such problems. Then, formal representations are explained. Afterwards, it summarizes the platform’s architecture. Finally, validation results are provided.