The application of nanoemulsions with different orange oil concentrations to remediate crude oil-contaminated soil

The petroleum industry stands out for causing significant environmental risks from contamination of the air, water and soil. The removal of organic pollutants from the environment poses a great technological challenge, making it increasingly necessary to develop efficient clean-up technologies. Surfactant solutions have been used to remediate soils and aquifers contaminated by hydrocarbons or crude oil derivatives. The aim of this study was to develop nanoemulsions and analyze their efficiency in extracting crude oil from a sand sample. The nanoemulsions were prepared by the phase inversion temperature (PIT) method. The oil phase consisted of orange oil and the nonionic surfactant ethoxylated lauryl ether (Ultrol L70) was used to stabilize the nanoemulsions. The surfactant concentrations were varied from 10 to 12 wt% and the oil phase from 5 to 20 wt%. The efficiency of extraction of oil from sand was assessed using the two nanoemulsions that presented the greatest stability (containing 5 wt% oil phase with 12 wt% surfactant and 20 wt% oil phase with 10 wt% surfactant). A 2(3) factorial experimental design with center point was used to evaluate and improve the soil washing process, varying the time, temperature and agitation speed of the system. The highest efficiencies were obtained at 45 degrees C.     

Assessment of different configurations for combined parabolic-trough (PT) solar power and desalination plants in arid regions

The combination of desalination technology into concentrating solar power (CSP) plants needs to be considered for the planned installation of CSP plants in arid regions. There are interesting synergies between the two technologies, like the possibility of substituting the condenser of the power cycle for a thermal desalination unit. This paper presents a thermodynamic evaluation of different configurations for coupling parabolic-trough (PT) solar power plants and desalination facilities in a dry location representing the Middle East and North Africa (MENA) region. The integration of a low-temperature multi-effect distillation (LT-MED) plant fed by the steam at the outlet of the turbine replacing the condenser of the power cycle has been simulated and compared with the combination of CSP with a reverse osmosis (RO) plant. Furthermore, an additional novel concept of concentrating solar power and desalination (CSP+D) has been evaluated: a LT-MED powered by the steam obtained from a thermal vapour compressor (TVC) using the exhaust steam of the CSP plant as entrained vapour and steam extracted from the turbine as the motive vapour of the ejector. This new concept (LT-MED-TVC) has been analyzed and compared with the others, evaluating its optimization for the integration into a CSP plant by considering different extractions of the turbine.     

Microstructure and corrosion behaviour of pulsed plasma-nitrided AISI H13 tool steel

The effect of pulsed plasma nitriding temperature and time on the pitting corrosion behaviour of AISI H13 tool steel in 0.9% NaCl solutions was investigated by cyclic polarization. The pitting potential (E_pit) was found to be dependent on the composition, microstructure and morphology of the surface layers, whose properties were determined by X-ray diffraction and scanning electron microscopy techniques. The best corrosion protection was observed for samples nitrided at 480 °C and 520 °C. Under such experimental conditions the E_pit-values shifted up to 1.25 V in the positive direction.     

Discovery of novel non-cyclam polynitrogenated CXCR4 coreceptor inhibitors

HIV cell fusion and entry have been validated as targets for therapeutic intervention against infection. Bicyclams were the first low-molecular-weight compounds to show specific interaction with CXCR4. The most potent bicyclam was AMD3100, in which the two cyclam moieties are tethered by a 1,4-phenylenebis(methylene) bridge. It was withdrawn from clinical trials owing to its lack of oral bioavailability and cardiotoxicity. We have designed a combinatorial library of non-cyclam polynitrogenated compounds by preserving the main features of AMD3100. At least two nitrogen atoms on each side of the p-phenylene moiety, one in the benzylic position and the other(s) in the heterocyclic system were maintained, and the distances between them were similar to the nitrogen atom distances in cyclam. A selection of diverse compounds from this library were prepared, and their in vitro activity was tested in cell cultures against HIV strains. This led to the identification of novel potent CXCR4 coreceptor inhibitors without cytotoxicity at the tested concentrations.     

Vascular effects and antihypertensive properties of κ-casein macropeptide

The blood-pressure-lowering effect of bovine κ-casein macropeptide (CMP), previously reported to exhibit a modest angiotensin-converting enzyme (ACE)-inhibitory activity in vitro, was evaluated in spontaneously hypertensive rats (SHR). The oral administration of CMP (150 mg kg⁻¹) significantly reduced the systolic blood pressure (SBP) of SHR. The antihypertensive action was more pronounced when CMP was treated with trypsin. The sequence MAIPPKK, identified in the tryptic hydrolysate of bovine CMP, significantly reduced blood pressure at a dose of 10 mg kg⁻¹. The CMP and its tryptic peptides induced relaxation of endothelium-intact aortic rings. The sequence MAIPPKK also evoked a significant relaxation effect; however, the shorter sequence MAIPPK and the strong ACE-inhibitory tripeptide IPP exhibited a vascular relaxing effect lower than 10%. The implications of vascular relaxing mechanisms, as well as the possibility that the tripeptide IPP is at least partially responsible for the antihypertensive effects of CMP, are discussed.     

Hydrolytic activity of Penicillium chrysogenum Pg222 on pork myofibrillar proteins

Moulds grow on many different dry-cured meat products and are able to hydrolyse muscle proteins. However, their contribution to proteolysis in these products is not well known. Only recently, the ability of just a few strains of Penicillium spp. to increase proteolysis in dry-cured meat products has been shown. For these strains to be used as starter cultures, their hydrolytic activity under standard conditions should be characterised. With this purpose, the effect of Penicillium chrysogenum Pg222 on pork myofibrillar proteins has been assayed in a culture medium containing 5% (w/v) NaCl. SDS-PAGE revealed that Pg222 was responsible for extensive hydrolysis of the main myofibrillar proteins except alpha-actinin. The proteolysis led to increases in free amino acids, reaching peak values at 84 h. Ala, Tyr and Lys were present in the greatest amount. These results suggest that P. chrysogenum Pg222 would contribute to development of desired texture and flavours in dry-cured meat products.     

Effect of processing conditions on some functional characteristics of extrusion‐cooked cassava starch/wheat gluten blends

Extrusion‐cooked blends of cassava starch (CS) and wheat gluten (WG) were studied. The data were analysed using response surface methodology. The results showed the formation of new structures characterised by lower radial expansion (RE) and specific volume (SV) when gluten was added to CS. WG content was the most important variable affecting RE, water absorption index (WAI), water solubility index (WSI), SV and difference in colour (ΔE) of the extruded products, but feed moisture content and barrel temperature also influenced RE. WAI was affected by a significant interaction between WG content and barrel temperature. The extruded products had lower WAI values and higher WSI values than WG‐free products. Heat, high shear rate and high pressure during extrusion cooking caused mechanical destruction or denaturation of the WG and gelatinisation and dextrinisation of the starch components. The extruded blends could have diverse applications. © 2002 Society of Chemical Industry     

Characterisation of the casein fraction of Ibérico cheese by electrophoretic techniques

The physicochemical characteristics of Ibérico cheese, a semi‐hard Spanish variety manufactured from mixtures of cow's, ewe's and goat's milk, were studied. The casein fraction and breakdown products of 6‐month‐old cheeses were characterised by various electrophoretic techniques: urea polyacrylamide gel electrophoresis (urea‐PAGE) at alkaline pH, isoelectric focusing (IEF) and two‐dimensional polyacrylamide gel electrophoresis (2DE). Proteins were separated in 2DE according to their charge/mass ratio by urea‐PAGE at alkaline pH in the first dimension and according to their isoelectric point by IEF in the second dimension. Some individual bands considered homogeneous by urea‐PAGE at alkaline pH (ie different grades of phosphorylation of α_s1‐casein and α_s2‐casein) or by IEF (ie overlapping of several bands of α_s2‐casein with γ‐casein bands) were found to be complex mixtures of casein components by 2DE. The two‐dimensional electrophoretic pattern was characteristic of the milk of each animal species included in Ibérico cheese. Capillary electrophoresis (CE) was also used to study the Ibérico cheeses. The high resolution of this technique allowed the identification of the main caseins of the different species (ie para‐κ‐casein, β‐casein, γ₂‐casein and γ₃‐casein). © 2002 Society of Chemical Industry     

Characterization of cheese proteolysis by capillary electrophoresis and reverse-phase HPLC analyses of peptides

 The possibilities of reverse-phase high performance liquid chromatography (RP-HPLC) and capillary electrophoresis (CE) when used for separation of cheese peptides are discussed. A CE method using a coated capillary column and a low pH buffer was developed to analyze the water-soluble fraction of a 6-month-old cow’s milk cheese. The CE patterns were compared with the chromatograms obtained by RP-HPLC using a C18 column and a gradient of acetonitrile in water. The CE method gave shorter analysis times but RP-HPLC provided lower coefficients of variation of the retention times and better detection limits. In addition, the elution behavior of peptides in CE strongly depended on the sample matrix. The results show that both techniques provide complementary information for the analysis of cheese peptides. Received: 10 June 1997 / Revised version: 20 October 1997