Maria Cristina Annesini

Olive oil mill effluent: Ageing effects on evaporation behaviour

Abstract Evaporation and distillation processes have been often used to treat wastewater from olive oil mill effluent: the effluent COD reduction varies widely with the characteristics of the waste. In this work we report some distillation tests on centrifuged olive oil mill effluent, performed in order to analyse the effect of storage time on the evaporation behaviour of this waste. Experimental data show that the ageing processes cause an increase in the concentrations of volatile compounds. According to a preliminary model such a behaviour can be described in terms of a chemical and a biochemical reaction between a few pseudo-compounds.

Two-phase partitioning bioreactors operating with polymers applied to the removal of substituted phenols.

Significant improvement in biodegradation performance has been demonstrated arising from the reduction of cytotoxicity provided by the sequestering of 4-nitrophenol (4NP) within Hytrel polymer beads added to a two-phase partitioning bioreactor (TPPB) operating in sequencing batch reactor (SBR) mode. This reduced toxicity is particularly apparent as the feed substrate concentration is increased; in fact it was shown that at a feed of 1000 mg/L 4NP, the inhibitory effect of the substrate completely prevents degradation from occurring in a single-phase system, whereas at only a 5% polymer loading, rapid and compete biodegradation is achieved. Different polymer/aqueous phase ratios were used to detoxify varying feed concentrations, and degradation rates were enhanced through the use of increased polymer loadings. As demonstrated in oxygen uptake experiments, the addition of polymers also reduces the maximum demand for oxygen, relative to single-phase operation, and smoothes the demand for oxygen throughout the degradation process. Polymer regeneration has also been further characterized by quantifying the number of methanol washes required to achieve satisfactory 4NP residuals, and the addition of a small amount of cosolvent has been shown to dramatically increase the rate of bioregeneration to produce beads ready for reuse.

Removal of oxygenated pollutants from wastewater by polymeric resins: data on adsorption equilibrium and kinetics in fixed beds

Abstract The aqueous phase adsorption of methyl- tert -butyl ether (MTBE) and tert -butyl alcohol (TBA) onto an Amberlite resin at 20°C was investigated under different operating conditions. To this end, both batch and fixed-bed experiments were performed on single solute and bisolute mixtures. The single-solute equilibrium data were fitted by means of the Freundlich equation and isotherm parameters were determined. The data on bisolute adsorption showed a strong competitive effect between MTBE and TBA, which can be described by means of a theoretical model accounting for the non-ideal behaviour of adsorbed phase. Experimental breakthrough curves were determined for single-solute solutions in order to evaluate the overall mass transfer coefficients between liquid and adsorbed phases. A predictive model for multisolute fixed-bed adsorption is proposed and the theoretical results are compared with experimental data.

Predictive criteria for the outcome of patients with acute liver failure treated with the albumin dialysis molecular adsorbent recirculating system.

The aim of this study was to evaluate the improvement of prognostic parameters after treatment with the molecular adsorbent recirculating system (MARS) in patients with fulminant hepatitis (FH). The parameters conducive to a positive prognosis include: Glasgow Coma Scale (GCS) score ≥11, intracranial pressure (ICP) <15 mm Hg or an improvement of the systolic peak flow of 25–32 cm/s via Doppler ultrasound in the middle cerebral artery, lactate level <3 mmol/L, tumor necrosis factor‐α <20 pg/mL, interleukin (IL)‐6 <30 pg/mL, and a change in hemodynamic instability from hyperkinetic to normal kinetic conditions, and so define the timing (and indeed the necessity) of a liver transplant (LTx). From 1999 to 2008 we treated 45 patients with FH with MARS in the intensive care unit of our institution. We analyzed all the parameters that were statistically significant using univariate analysis and considered the patients to be candidates for inclusion in a multivariate logistic regression analysis. Thirty‐six patients survived: 21 were bridged to liver transplant (the BLT group) and 15 continued the extracorporeal method until native liver recovery (the NLR group) with a positive resolution of the clinical condition. Nine patients died before transplantation due to multi‐organ failure. We stratified the entire population into three different groups according to six risk factors (the percentage reduction of lactate, IL‐6 and ICP, systemic vascular resistance index values, GCS <9, and the number of MARS treatments): group A (0–2 risk factors), group B (3–4 risk factors), and group C (5–6 risk factors). Analyzing the prevalence of these parameters, we noted that group A perfectly corresponded to the NLR group, group B corresponded to the BLT group, and group C was composed of patients from the non‐survival group; thus, we were able to select the patients who could undergo a LTx using the predictive criteria. For patients with an improvement of neurological status, cytokines, lactate, and hemodynamic parameters, LTx was no longer necessary and their treatment continued with MARS and standard medical therapy.

Solubility, spectroscopic properties and photostability of Rhein/cyclodextrin inclusion complex

The host-guest interaction between Rhein (Rh)--an anthraquinonic drug characterized by low water solubility and recently considered for its potential antidiabetic and antitumoral activities other than for the well-established anti-inflammatory properties--with cyclodextrins (CDs) was investigated using phase-solubility diagrams. The typical A(L) phase-solubility profiles suggest the formation of the 1:1 inclusion complexes between Rh and the two CDs investigated, namely beta-cyclodextrin and 2-hydroxypropyl-beta-cyclodextrin and the resulting constant values of complex formation, K(c), were estimated. Due to the higher K(c) value, complex of Rhein with 2-hydroxypropyl-beta-cyclodextrin was chosen for further investigation. Characterization in solution of 2-hydroxypropyl-beta-cyclodextrin/Rhein complex was achieved both by fluorescence and visible spectroscopic techniques. These results confirm the formation of inclusion complexes in solution and the 1:1 stoichiometry of the binary system. With respect to Rhein aqueous solution behavior, the inclusion complex appears to be able: (i) to enhance Rhein solubility; (ii) to control its neutral/anionic equilibrium; (iii) to affect both its electronic absorption and fluorescence spectra. Finally, the photostability of Rhein in the presence of cyclodextrins was evaluated.

Cytokine Level Modifications: Molecular Adsorbent Recirculating System Versus Standard Medical Therapy

INTRODUCTION Acute-on-chronic liver failure (ACLF) is a systemic inflammatory reaction, which is characterized by a predominantly proinflammatory cytokine profile, causing the transition from stable cirrhosis to ACLF. The aim of the present study was to evaluate the changes in several cytokines associated with inflammatory liver disease and liver regeneration among 15 ACLF patients treated with the Molecular Adsorbent Recirculating System (MARS) compared with 15 patients treated with standard medical therapy (SMT). The subjects showed various disease etiologies but similar values for Model End-stage Liver Disease scores. METHODS In the MARS group, 15 (10 male and 5 female) patients were treated with MARS (Gambro). The number of MARS applications was nine; the length of applications was 8 hours. In the SMT group; 15 (10 male and 5 female) patients were treated with SMT. The patients were monitored for 30 days from inclusion with a survival follow-up at 3 months. Statistical results were calculated with SPSS14.0 (SPSS Inc, Chicago, Ill). A P < .07 was considered significant. RESULTS In the MARS group, we observed significant changes in the levels of Interleukin (IL)-6, IL-1, IL-10, and tumor necrosis factor (TNF)-alpha in association with improved hepatocyte growth factor. Patient survival at 3 months was 60%. The SMT group showed only a significant change in TNF-alpha (P = .03). Patient survival at 3 months was 30%. CONCLUSION The MARS liver support device corrected pathophysiologies of ALF and may be used to enhance spontaneous recovery or as a bridge to transplantation.

Two-phase reactors applied to the removal of substituted phenols: comparison between liquid-liquid and liquid-solid systems

In this paper, a comparison is provided between liquid-liquid and liquid-solid partitioning systems applied to the removal of high concentrations of 4-nitrophenol. The target compound is a typical representative of substituted phenols found in many industrial effluents while the biomass was a mixed culture operating as a conventional Sequencing Batch Reactor and acclimatized to 4-nitrophenol as the sole carbon source. Both two-phase systems showed enhanced performance relative to the conventional single phase bioreactor and may be suitable for industrial application. The best results were obtained with the polymer Hytrel which is characterized by higher partition capability in comparison to the immiscible liquid solvent (2-undecanone) and to the polymer Tone™. A model of the two systems was formulated and applied to evaluate the relative magnitudes of the reaction, mass transfer and diffusion characteristic times. Kinetic parameters for the Haldane equation, diffusivity and mass transfer coefficients have been evaluated by data fitting of batch tests for liquid-liquid and liquid-solid two phase systems. Finally, preliminary results showed the feasibility of polymer regeneration to facilitate polymer reuse by an extended contact time with the biomass.

Surfactant as modulating agent of enzyme‐loaded liposome activity

Large phosphatydilcholine unilamellar vesicles appear to be suitable controlled and protective delivery systems of beta-galactosidase. Kinetic measurements carried out on intact loaded liposomes show that most of the enzyme is entrapped inside the liposomes and its activity is latent. Nevertheless, intact liposomes also show significant activity, which can be controlled by addition of detergent. At sublytic detergent concentrations, liposome enzymatic activity reaches values two or three times greater than those of intact liposomes. This increase seems to be due to membrane structure modification that also enhances the substrate permeability across the bilayer. (c) 1997 John Wiley & Sons, Inc. Biotechnol Bioeng 55: 261-266, 1997.

CARBON DIOXIDE HYDRATION WITH LIPOSOMES ENTRAPPING CARBONIC ANHYDRASE

Liposomes entrapping enzymes behave as small membrane bioreactors which can be used in biotechnological and biomedical applications. Furthermore, liposomes loading enzymes are being used as model to mimic cellular and subcellular organel behaviour. This work deals with the study of the kinetic behaviour of carbonic anhydrase (CA) entrapped in lipid vesicle. CA is nearly ubiquitous, being present in many tissues of different species, in cells, subcellular particles and membranes. The carbonic anhydrase entrapment in liposomes, as a function of the lipid cocktail used, was studied preliminarily. Then kinetics of carbon dioxide hydration reaction, catalysed by CA entrapped in liposomes, has been studied.

Kinetics of surfactant-induced release from liposomes: a time-dependent permeability model

Abstract The article examines membrane permeabilization and the consequent content release of lipid vesicles due to the addition of surfactant. Experimental results show that content release involves a complex kinetics where almost instantaneous release is followed by prolonged slow leakage. The model proposed therefore regards bilayer permeability as varying with the time elapsed from the moment of surfactant addition. A delta function followed by an exponentially decaying profile is assumed for these permeability curves. The effects of surfactant concentration and type (Triton X-100, Tween 20 and Tween 60) can be compared by comparing the fitting parameters of the permeability curves.