Interdisciplinary research: roles for self-organization

No generally accepted principles and guidelines currently exist to help engineers design local interaction mechanisms that result in a desired global behavior. However, several communities have developed ways of approaching this problem in the context of niched application areas. Because the ideas underlying these approaches are often obscured or underemphasized in technical papers, the authors review the role of self-organization in their work. They provide a better picture of the status of the emerging field of self-organizing systems or autonomic computing.     

An integrated system to remote monitor and control anaerobic wastewater treatment plants through the internet.

The TELEMAC project brings new methodologies from the Information and Science Technologies field to the world of water treatment. TELEMAC offers an advanced remote management system which adapts to most of the anaerobic wastewater treatment plants that do not benefit from a local expert in wastewater treatment. The TELEMAC system takes advantage of new sensors to better monitor the process dynamics and to run automatic controllers that stabilise the treatment plant, meet the depollution requirements and provide a biogas quality suitable for cogeneration. If the automatic system detects a failure which cannot be solved automatically or locally by a technician, then an expert from the TELEMAC Control Centre is contacted via the internet and manages the problem.     

Comparison of a modified Sugiura procedure with portal systemic shunt for prevention of recurrent variceal bleeding in cirrhosis

BACKGROUND: There is no agreement on the management of patients with cirrhosis and recurrent variceal bleeding after failure of medical or endoscopic treatments or both. Portal systemic shunts are highly effective in preventing rebleeding but are associated with a high incidence of chronic encephalopathy. This study compared the results of a slightly modified Sugiura procedure (esophageal transection plus esophagogastric devascularization plus splenectomy) with those of nonselective portal systemic shunts in patients with previous variceal bleeding. METHODS: Fifty-four patients were included in this randomized controlled study between January 1984 and April 1989. The major end point was chronic encephalopathy. Secondary end points were recurrent variceal bleeding, survival, ascites, and hepatocellular carcinoma. RESULTS: Twenty-seven patients were assigned to each group. The rate of chronic encephalopathy was significantly (p = 0.002) lower after modified Sugiura procedure than after portal systemic shunt. Recurrent variceal bleeding was more frequent after modified Sugiura procedure than after portal systemic shunt, but the difference is not significant. One-, two-, and three-year survival rates were 93%, 81%, and 67%, respectively, in the modified Sugiura group and 78%, 66%, and 39%, respectively, in the portal systemic shunt group (p = 0.044). CONCLUSIONS: These results suggest that the modified Sugiura procedure is better overall than the nonselective portal systemic shunt in the management of patients with cirrhosis and recurrent variceal bleeding. Although the rebleeding rate is higher after the modified Sugiura procedure, this does not seem to affect mortality in these patients.     

Transmission loss allocation through equivalent bilateral exchanges and economical analysis

A new loss allocation (LA) scheme based on the principle of equivalent bilateral exchanges (EBEs) is presented and compared with other available techniques. Formulation and results from extensive simulations including consistency tests show that the suggested methodology has several desirable properties: It is flow-based, requiring only a solved load flow for its implementation; it is not dependent on the choice of a slack bus; it is straightforward to apply; undesirable negative loss allocation is not produced; and low volatilities are shaped. An economic analysis with various LA methods is also carried out when these are integrated into a combined economic dispatch/load flow dispatch strategy, a likely scenario for LA in a real system. This combined dispatch strategy yields prices charged to the loads and rates received by the generators that account for loss allocation and loss supply. Results show that these economic indexes are very close to the marginal costs derived from an optimal power flow (OPF) approach with the advantage of reducing volatility.     

Unusual essential oils with aromatic properties

Summary The essential oil obtained by steam distillation of cinchona bark (Cinchona spp.,Rubiaceae family) — a plant well known for its pharmacological properties, also employed in the food industry, especially in making liqueurs - was investigated. The oil, of completely unknown chemical composition, was analyzed by GLC and GLC/MS after separation on a silica gel column, and one hundred components were identified. The presence of 2-hexyl-3-methylmaleic anhydride is rather unusual.

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Ungewöhnliche ätherische Öle mit aromatischen Eigenschaften. Die flüchtigen Aromastoffe der China-Rinde

Zusammenfassung Es wurde ätherisches Öl analysiert, das durch Wasserdampfdestillation von Chinarinde (Cinchona spp. derRubiaceae-Familie) gewonnen wurde. Diese Pflanze ist aufgrund ihrer pharmakologischen Eigenschaften bekannt und wird auch in der Lebensmittelindustrie verwendet, ganz besonders für die Likör- und Magenbitterherstellung. Die chemische Zusammensetzung dieses Öls war unbekannt. Nach Abtrennung auf einer Kieselgelsäule wurden im Öl mit GLC und GLC/MS etwa 100 Verbindungen identifiziert. Das Vorhandensein von 2-Hexyl-3-methyl-maleinsäureanhydrid ist ziemlich ungewöhnlich.

     

Epoxide polymerization

Summary Poly(propylene oxide), PPO, obtained using diphenylzinc, Ph₂Zn, and using the diphenylzinc-water system at various molar ratios H₂O/Ph₂Zn, were studied through ¹H NMR and IR spectroscopy establishing that the polymerization initiates by coordition of propylene oxide (PO) to a terminal zinc atom of the active species followed by consecutive insertions of PO units at this zinc atom. The PPO obtained showed Ph-and HO-, HO-and HO-end-groups depending on the molar ratio H₂O/Ph²Zn used, and also HO-and PhO-end-groups when oxygen was present in the polymerization system.     

An optimal algorithm for the boundary of a cell in a union of rays

In this paper we study a cell of the subdivision induced by a union ofn half-lines (or rays) in the plane. We present two results. The first one is a novel proof of theO(n) bound on the number of edges of the boundary of such a cell, which is essentially of methodological interest. The second is an algorithm for constructing the boundary of any cell, which runs in optimal (n logn) time. A by-product of our results are the notions of skeleton and of skeletal order, which may be of interest in their own right.This work was partly supported by CEE ESPRIT Project P-940, by the Ecole Normale Supérieure, Paris, and by NSF Grant ECS-84-10902.This work was done in part while this author was visiting the Ecole Normale Supérieure, Paris, France.     

Changes in free amino acids content in albacore (Thunnus alalunga) muscle during thermal processing

Summary The effects of cooking and sterilization at several temperatures on the free amino acids (FAA) content in albacore (Thunnus alalunga) muscle were studied during the processing of canned tuna. FAAs were derivatized witho-phtalaldehyde, separated on a C18 column by HPLC and detected by both fluorescence and ultra-violet detectors. After cooking the loss of FAAs was not significant. However, in the final product sterilized at 115 °C and 110 °C (throughout the whole process) there were significant losses with regard to the start material, but not at 118 °C (all temperatures leading to the same lethal F-value). The influence of the thermal process time at 115 °C was evaluated for 60 and 100 min. Significant losses were found between both canned products (25%) and between the raw fish and the final product (12% and 34%, process time 60 and 100 min, respectively). The determination of the content of FAA present in canned albacore may be a useful indication of the severity of the thermal processing.

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Veränderung im Gehalt an freien Aminosäuren in Thunfischmuskel (Tunnus alalunga) während der Wärmebehandlung

Zusammenfassung Die Wirkung des Kochens und Sterilisierens bei verschiedenen Temperaturen auf den Gehalt an freien Aminosäuren (FAA) im Thunfischmuskel (Thunnus alalunga) wurde während der Herstellung von Thunfischkonserven untersucht. Die freien Aminosäuren wurden mito-Phtalaldehyd derivatisiert, auf einer C-18-Kolonne mit HPLC abgetrennt und durch Fluorescenz und UV-Detektoren nachgewiesen. Nach dem Kochen war der Verlust an FAA nicht signifikant, jedoch in dem bei 110° und 115 °C sterilisierten Endprodukt ergaben sich signifikante Verluste bezogen auf das Ausgangsmaterial, aber nicht auf das bei 118 °C erhitzte; alle Erhitzungstemperaturen führen zu demselben letalen F-Wert. Der Zeiteinfluß der Erhitzung bei 115 °C wurde bei 60 und 100 min bewertet. Signifikante Verluste sind bei beiden Dosenkonserven aufgetreten (25%) und zwischen diesen und dem Rohfisch ( 12% und 34%) bei einer Erhitzungszeit von 60 und 100 min). Die Bestimmung des FAA-Gehalts in Thunfischkonserven kann für den Nachweis der Einwandfreiheit des thermischen Prozesses sehr nützlich sein.

     

The AFLATOX® Project: Approaching the Development of New Generation,Natural-Based Compounds for the Containment of the Mycotoxigenic Phytopathogen Aspergillus flavus and Aflatoxin Contamination

The control of the fungal contamination on crops is considered a priority by the sanitary authorities of an increasing number of countries, and this is also due to the fact that the geographic areas interested in mycotoxin outbreaks are widening. Among the different pre- and post-harvest strategies that may be applied to prevent fungal and/or aflatoxin contamination, fungicides still play a prominent role; however, despite of countless efforts, to date the problem of food and feed contamination remains unsolved, since the essential factors that affect aflatoxins production are various and hardly to handle as a whole. In this scenario, the exploitation of bioactive natural sources to obtain new agents presenting novel mechanisms of action may represent a successful strategy to minimize, at the same time, aflatoxin contamination and the use of toxic pesticides. The Aflatox^® Project was aimed at the development of new-generation inhibitors of aflatoxigenic Aspergillus spp. proliferation and toxin production, through the modification of naturally occurring molecules: a panel of 177 compounds, belonging to the thiosemicarbazones class, have been synthesized and screened for their antifungal and anti-aflatoxigenic potential. The most effective compounds, selected as the best candidates as aflatoxin containment agents, were also evaluated in terms of cytotoxicity, genotoxicity and epi-genotoxicity to exclude potential harmful effect on the human health, the plants on which fungi grow and the whole ecosystem.