H+Ca2+ Ion-exchange process in α-titanium phosphate

The behavior of α-titanium phosphate in the $\text{H}{}^{\mathrm{+}}\text{Ca}{}^{\mathrm{2+}}$ ion-exchange by addition of CaCl₂, (CaCl₂+HCl),(CaCl₂+Ca(OH)₂) and Ca(OH)₂ was studied. The conversion is not total in the absence of Ca(OH)₂, the addition of (CaCl₂+HCl) giving a maximum value of 36% and that of CaCl₂ a value of 64%. In the presence of Ca(OH)₂ the full substitution can be reached though the process occurs with hydrolysis of the exchanger and precipitation of calcium phosphate and titanium oxide. The results are compared with those obtained in α-zirconium phosphate.     

The detection of residual pectin methylesterase activity in pasteurized tomato juices

The enzyme pectin methylesterase (PME) is believed to be involved in the destabilization and cloud loss of vegetable juices through the de-esterification of pectin followed by the successive coprecipitation of the pectate with insoluble materials present in the juices. Cloud destabilization is often observed even when the vegetable products have been subjected to thermal treatment to produce sterile products and also to stabilize the cloud. Therefore it is possible that loss of cloud may be because of residual enzymatic activities surviving the thermal treatments. However, so far no evidence demonstrating the existence of residual PME activity in pasteurized juices has been published. In this paper it is reported that in industrial tomato products showing cloud loss residual PME activity is present. It has been possible to detect this very low activity by an affinity chromatography procedure. The method is based on a cyanogen bromide-activated resin which is coupled with a pectin methylesterase inhibitor protein purified from kiwi fruit. This resin binds native PME with high selectivity and the enzyme can be concentrated from the product in a single step. Thus, the very low PME residual activity present in pasteurized juice and generally not detectable with common techniques can be detected and easily determined with the method described in this paper.     

Mobile robot motion estimation by 2D scan matching with genetic and iterative closest point algorithms

The paper reports on mobile robot motion estimation based on matching points from successive two‐dimensional (2D) laser scans. This ego‐motion approach is well suited to unstructured and dynamic environments because it directly uses raw laser points rather than extracted features. We have analyzed the application of two methods that are very different in essence: (i) A 2D version of iterative closest point (ICP), which is widely used for surface registration; (ii) a genetic algorithm (GA), which is a novel approach for this kind of problem. Their performance in terms of real‐time applicability and accuracy has been compared in outdoor experiments with nonstop motion under diverse realistic navigation conditions. Based on this analysis, we propose a hybrid GA‐ICP algorithm that combines the best characteristics of these pure methods. The experiments have been carried out with the tracked mobile robot Auriga‐α and an on‐board 2D laser scanner. © 2006 Wiley Periodicals, Inc.     

On the Use of Symbolic Analyzers in Circuit Synthesis

In this paper several examples of circuits obtained with an automatic synthesis algorithm will be shown. The algorithm, described in a companion paper [1] and outlined here for clarity, has been implemented in the Mathematica language. We applied the new algorithm to classical problems of inmittance synthesis, obtaining well known topologies and also non-reported structures. When the algorithm is applied to challenging new problems, novel and practically useful inmittances are synthesized.     

Improvement of resolution in equivalent currents reconstruction using Papoulis-Gerchberg algorithm and replicas of the spectrum

A new algorithm to increase the resolution in the reconstruction of equivalent currents from spherical near-field measurements is proposed. The algorithm obtains the non-visible part of the plane- wave spectrum used for the reconstruction. This is achieved by means of a band-limited extrapolation method, the Papoulis-Gerchberg algorithm, and the replication of the known part of the spectrum. The gain in resolution is from llambda in the method without the algorithm proposed, to 0.4-0.51 with this new algorithm. Results with real measurements are shown.     

The Antipsychotic Risperidone Alters Dihydroceramide and Ceramide Composition and Plasma Membrane Function in Leukocytes In Vitro and In Vivo

Atypical or second-generation antipsychotics are used in the treatment of psychosis and behavioral problems in older persons with dementia. However, these pharmaceutical drugs are associated with an increased risk of stroke in such patients. In this study, we evaluated the effects of risperidone treatment on phospholipid and sphingolipid composition and lipid raft function in peripheral blood mononuclear cells (PBMCs) of older patients (mean age >88 years). The results showed that the levels of dihydroceramides, very-long-chain ceramides, and lysophosphatidylcholines decreased in PBMCs of the risperidone-treated group compared with untreated controls. These findings were confirmed by in vitro assays using human THP-1 monocytes. The reduction in the levels of very-long-chain ceramides and dihydroceramides could be due to the decrease in the expression of fatty acid elongase 3, as observed in THP-1 monocytes. Moreover, risperidone disrupted lipid raft domains in the plasma membrane of PBMCs. These results indicated that risperidone alters phospholipid and sphingolipid composition and lipid raft domains in PBMCs of older patients, potentially affecting multiple signaling pathways associated with these membrane domains.     

Designing a MAC Algorithm for Equitable Spectrum Allocation in Cognitive Radio Wireless Networks

Spectrum sharing is one of the most important stages in cognitive radio wireless networks, responsible for the opportunistic allocation of free channels to unlicensed users (SUs) to be utilized in data transmission. One of the critical issues at this stage, is related to the absence of a module capable of allocating the available resources fairly to all network users. In this sense, the paper develops a media access control protocol (MAC) for cognitive networks based on infrastructure called CRUD-MAC, which allows to take advantage of channel access in a more equitable and efficient way; for this purpose two algorithms we designed within the MAC standard (using ANFIS and FAHP) for the ranking or classification of SUs by score when assigned channels based on network usage historical metrics, so that nodes with better ranking have priority in the allocation. Validation of the proposals was made by comparing the performance of CRUD-MAC with ANFIS, FAHP, and a channel assignment algorithm, not including ranking. The results show that the system is more efficient from the standpoint of fair allocation of resources.