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The extraction of gibberellic acid (GA 3 ), a powerful vegetal growth promoter widely used in agriculture, has been studied using emulsion liquid membrane (ELM) technology. The system used in this study consisted of a water-in-oil emulsion made of KCl aqueous solution and n-heptane stabilised by the surfactant SPAN 80. Aliquat 336, a commonly used carrier, was added to organic phase in order to increase both mass transfer and selectivity. This emulsion was dispersed on either prepared aqueous solutions of GA 3 or fermentation broths. The fermentation was performed using the fungi Gibberella fujikuroi in fed-batch modality, achieving GA 3 concentrations around 0.65 g L −1 . Selection experiments pointed out that the most important variables in the extraction process were surfactant concentration (SPAN 80), carrier concentration (Aliquat 336), and time extraction. An optimisation experimental protocol was carried out using prepared GA 3 solutions, achieving the maximum extraction (88%) under the following conditions: Aliquat 336 4.3% (v/v); SPAN 80 4.4% (v/v); extraction time 20 s. When the optimisation of these variables was carried out using fermentation broth the optimum conditions found were Aliquat 336 7.4% (v/v); SPAN 80 11.2% (v/v) and extraction time 62 s. Under these conditions, the extraction yield was 68% and the concentration increase was 2.2-fold. These results suggest that GA 3 extraction using ELM is perfectly possible and its application in other configurations and scales, such as pilot scale column configuration should be considered.

In the last years, a considerable number of studies have been performed on the correlation between Helicobacter pylori infection and ischaemic heart disease. The reason is the supposed role of some chronic infections in the genesis and development of vessel wall injury and atheromatous plaque, as already reported for Chlamydia pneumoniae and herpes viruses. While this association may be theoretically conceivable, it still remains debated from a practical point of view. Epidemiological and animal studies as well as some eradicating trials gave conflicting results, while studies investigating the specific molecular mimicry mechanisms induced by H. pylori strongly support the association. Moreover, none of the studies performed so far did take into account the effect of the genetic susceptibility to develop ischaemic heart disease or to respond to H. pylori infection. In particular, while the exposure to some known risk factor for atherosclerosis should lead to develop ischaemic heart disease, no condition or exposure, either individual or in combination, completely explains the occurrence and the progression of the disease, as many patients develop ischaemic heart disease in the absence of any risk factor. Based on these concepts, can we state that H. pylori infection may cause the same effect in patients with ischaemic heart disease as in healthy subjects? Further studies are needed in order to clarify this issue.

Summary The Life cycle concept will become the backbone in a new industrial culture named sustainable production. Sustainability means that products are designed for their whole life cycle i.e. production, distribution, usage and disposal with minimized (acceptable) influence on the environment, occupational health and use of resources. A key element in this new engineering life cycle approach is a method/tool to assess and evaluate environmental, occupational health and resource consequences in all life cycle phases at the product development stage. In this paper a preliminary method for evaluating environmental consequences containing the major environmental effects is presented. The method outlined quantifies the term “environmental friendly” so it can be used as a “yardstick” in evaluating different technical solutions. The complex problems in the final design decisions are discussed and future perspectives outlined.

In 1938, Taquini 1 reported that, when the kidney of a dog is made completely ischemic, re-establishment of the renal circulation is followed by a rise in blood pressure. In a previous study, 2 it was found that the expected rise in blood pressure did not occur in rabbits following the termination of complete renal ischemia which had lasted four to six hours. At that time, the only way to account for the difference in the response of dogs and rabbits was to assume a species variation. Because of the negative response in rabbits, it seemed desirable to extend these observations to other animals; in this communication we are reporting the effects upon the blood pressure of re-establishment of the circulation of ischemic kidneys in cats, dogs, and rats.

The behavior of a Josephson system under pulsed operation is of utmost importance for developing reliable digital devices working at very high clock frequencies. Information about effect of thermal noise over pulsed operation is also useful to design errors free devices. Recent experiments in a system of two stacked junctions show that pulses applied to the first junction (injector) of the stack drive the Josephson biased second junction (detector) in the resistive state. The experiment was interpreted as pulsed-assisted escape toward resistive state as a consequence of an excitation of large non-linear oscillations in the detector junction that, with the contribution of thermal noise, drives out the junction from the zero voltage state. Moreover, an unstability of the resistive state toward the zero voltage state under the same pulsed operation was also noted. By means of a systematic numerical approach to the problem, we present a study of the pulsed-assisted escape using the framework of the thermal escape theory for the direct transition from zero voltage state to resistive state. We study the single junction case and a stacked configuration as examples of different systems showing pulsed-assisted escape. (C) 2002 Elsevier Science B.V. All rights reserved.