Transfer of metal ions in the soil-root interface: influence of copper(II) on the stability of the fibrils

A network of Ca-polygalacturonate arranged in fibrils similar to those of plant roots (Gessa C. and Deiana S., (1990); C.Gessa and Deiana S., (1990)) constitutes a very useful model far the study of the ionic transfer both in the soil-root interface and in the apoplast. Due to the fact that important properties of the network, such as the hydration degree and the absorption phenomena, vary dramatically with the reticulating ion (Gessa C. and Deiana S., (1989)), this note reports on the influence of the metal ions on the fibrillar structure of the network and gives further information about the transfer of the metal ions to the roots

Contributo dell'argilla e della sostanza organica alla capacità di scambio cationico delle terre brune della Sardegna Nord-Orientale

The contributions of clay and organic matter relative to 24 samples collected from non calcic brown soils of N-W Sardinia - were measured using statistical analyses. Within the limits of the standard errors the regression coefficients of day and organic matter increase linearly with pH. The average contribution to CEC of day decreased from 64% at pH 3 to 300% at pH 8. The clay CEC was 30, 34, 39 meq per 100 g. al pH 3,5 and 8, respectively, while that of the organic matter was 62, 131, 231 meq per 100 g. The high increase of CEC between pH 5 and 8 was interpreted in view of eventual liming of cultivable soils

Effetto dei detersivi commerciali sullo sviluppo di alcune specie vegetali di interesse agrario

Experiments have been realized on some agricultural vegetable species to study their growth behaviour in the presence of detersive, using to the purpose faur commercial detersives. The greatest phototoxic effects are felt by Lolium. Medicago and Tripholium. The detersive containing the no-ionic tensio-active shows the most depressing action

Use of pharmacological treatments by a sample of Italian patients affected by alcohol use disorders

Title: USE OF PHARMACOLOGICAL TREATMENTS BY A SAMPLE OF ITALIAN PATIENTS AFFECTED BY ALCOHOL USE DISORDERS Author name(s): R. Agabio; E.M. Diana; D. Grazzini; R. Pirastu; G.L. Gessa Institution: Department of Biochemical Sciences, Section of Neuroscience, Preclinical and Clinical Pharmacology, University of Cagliari, Italy Text Background: It has often been reported that the majority of patients affected by Alcohol Use Disorders (AUDs) do not receive any pharmacological treatment. This study was aimed at investigating the use of the medications available in Italy (disulfiram, naltrexone, acamprosate, and γ-hydroxybutyric acid) by a sample of outpatients affected by AUDs. Methods: Four trained psychologists interviewed outpatients affected by AUDs in an area of Sardinia, Italy, of approximately 550.000 adult inhabitants. Results: A total sample of 208 outpatients affected by AUDs was interviewed (~1/3 of total outpatients affected by AUDs of that area). Their main features were: 166 males (79.5%); mean age=48.6±0.6 year; duration of AUDs=15.8±0.7 years; number of drinks per drinking days=19.4±1.3; number of criteria of DSM-IV-Tr=5.8±0.1. Before the admission into specific services, 13 patients (6.2%) had already received medication for AUDs; 7 patients (3.4%) had received disulfiram and 6 patients (2.9%) γ-hydroxybutyric acid. Over the same period, 22 patients (10.6%) had already attended self-help groups and 4 patients (1.9%) had received thiamine (Vitamine B1). After the admission into specific medical settings for the treatment of AUDs, 113 patients (54.3%) received medication for AUDs: 58 patients (27.9%) received disulfiram, 65 patients (31.2%) γ-hydroxybutyric acid, 2 patients (1.0%) naltrexone, and 6 patients (2.9%) acamprosate. In the same period, 54 patients (26.0%) frequented self-help associations, and 21 patients (10.1%) received thiamine. Conclusions: The results of this study confirm that the number of patients who receive a treatment for AUDs continues to be surprisingly low. Despite the long duration and the high level of severity of the AUDs, the majority of patients affected by AUDs did not receive any treatment before their admission in specific medical settings for the treatment of AUDs (10% of patients frequented self-help groups, 6% received a medication for AUDs, and 2% thiamine). After the admission into specific medical settings, the number of patients who received a treatment increased: 26% frequented self-help associations, 54% received a specific medication, and 10% received thiamine. However, approximately half of the patients did not receive any pharmacological treatment even if they frequented medical settings for the treatment of AUDs. Additional work is needed to understand the reasons of such a scarce use of treatments. Acknowledgements: This study was supported by a grant from Regione Autonoma della Sardegna

Effects of Al substitution on goethite formation

Goethites containing up to 32.7 mole % Al were synthesized and characterized through diffractometry, spectrometry, DSC and chemical techniques. Results indicate that crystal growth was favoured or hindered depending on the percentage of aluminum incorporated into the structure. Goethites to which 5-10 mole % Al were initially added crystallized best, as shown by the highest crystallite dimensions calculated from X-ray and Mössbauer analyses, and by the lowest surface areas values. Over such substitution degree goethite crystallization was hindered and for sample synthesized in presence of 40 mole % Al the separation of a discrete amount of gibbsite and bayerite occurred. Both crystallinity and Al-substitution degree influenced the goethite dehydroxylation endothermic peak temperature playing a competitive action in the peak shift. In fact, the increase in the thermal stability induced by the presence of Al3+ ions into the structure was counteracted by the decrease due to the particle size reduction. The stabilizing effect of aluminum was confirmed by the oxalate treatment which removed from the Al-free sample a Fe amount higher than that from the sample containing about 20 mole % Al, although both had similar crystallinity

Transfer of metal ions at the soil-root interface: role of VO²⁺ on Fe³⁺ mobilization from a Fe(III)-network

This note reports the role of VO(IV) on Fe(III) mobilization from a Fe(III)-polygalacturonate network. The effect of the reaction on the physical properties of the system is also considered

Role of the polygalacturonate network on the iron (III) reduction by caffeic acid

This communication reports the role of polygalacturonate network on the Fe(III) reduction by caffeic acid. The effect of phosphate ions on the redox reaction is also considered

Role of the caffeic acid oxidation products on the iron mobilization at the soil-root interface

Previous results show that the reduction of Fe(III) by caffeiic acid (CAF) is strongly influenced by the pH of the reaction medium (DEIANA et al., 1995). In particular, it has been found that al pH > 3.8 the reducing activity of CAF towards the Fe(III) ions in solution is low, but it increases when Fe(III) is complexed as Fe(III)-polygalacturonate. The mobilization of the Fe(II) ions, which form upon the Fe(III) reduction, has been shown to depend mainly on the nature of the Fe(III)-polygalacturonate complexes (DEIANA et al., 1994a). In particular, it bas been observed a high redox activity of CAF towards Fe(III) when the metal ion is coordinated by the carboxilic groups of the macromolecule. The Fe(III) reduction has been found to decrease when an oxydrilic group was inserted in the Fe(III) coordination sphere. The Fe(II) produced partly diffuses into the external solution and partly is still strongly held by the polysaccharidic matrix. The oxidation of CAF by Fe(III) gives rise to the formation of products (OP) with different polymerization degree, some of which are similar to those found in natural systems (DEIANA et al., 1994b). In order to determine the role of these products in the Fe(III) reduction as well as in the mobilization of the Fe(II) produced it was set up an electrochemical method to synthetize these products (DEIANA et al., 1994b). Here are reported some results about the interaction which establish between the CAF oxidation products and iron in both oxidized and reduced form

Describing the adsorption of potential determining ions on variable charge mineral surfaces

A computer program was developed to elaborate the titration curves of amphoteric surfaces according to the double layer theory. The zpc, identified from the intersection point of the titration curves carried out at different ionic strengths, fell at pH 3.15, 9.45 and 7.65 for Si, AI and Fe hydroxides, respectively. The Stern model described quite satisfactorily the relation between σ0 and ψ0. Some problem was presented by Si surfaces which were then treated by a different calculation procedure. The δ values, the Stern layer thickness, were very high for the SI surfaces and increased with decreasing ionic strength. A different behaviour was showed by AI and Fe hydroxides; in these cases δ values were very low and increased with increasing electrolyte concentration. These results were discussed in terms of surface structures and activity of the supporting electrolyte