Kinetics and Mechanism of Catalytic Ozonation of Aqueous Pollutants on Metal Oxide Catalysts

The catalytic ozonation of fenofibric and clofibric acids and the herbicides atrazine and linuron was studied using titanium dioxide, alumina, and manganese oxide supported on activated alumina and on silica SBA-15. The organics studied did not adsorb significantly either in wastewater or in phosphate-buffered water. The catalysts did not modify the rate of the hydroxyl-mediated ozonation with respect to the homogeneous value. The mode of action of metal oxide catalysts would be an enhanced generation of oxidant species from the catalytic decomposition of ozone. All catalysts increased the efficiency in the production of hydroxyl radicals from ozone.     

Prototyping Vitruvius, New Challenges: Digital Education, Research and Practice

This paper discusses a key subject of research at ISCTE-IUL. Digital fabrication in architecture offers new perspectives and design innovation in three main areas: academia, research and professional practice. In order to investigate these new challenges and its contributions to architecture in Portugal, a group of multidisciplinary researchers organized a symposium that presented a state of the art in digital fabrication. The main points were the creation of the Vitruvius FabLab?CIUL laboratory and the definition of appropriate new lines of research in digital fabrication.     

Roasting process affects the profile of diterpenes in coffee

There is no consensus in the literature regarding the decrease of kahweol and cafestol contents during coffee roasting, but it has been reported that these compounds can undergo dehydration under heat. Kahweol and cafestol were quantified in Arabica and Robusta coffees with different roasting degrees (2, 4, 6, 8 and 10 min at 230 °C). The structures of the diterpenes and the presence of derivative compounds were determined by liquid chromatography with UV–Vis and mass spectrometry detection. In the dark roast samples, dehydro derivatives were found. The roasting process influenced the level of diterpenes in both species of coffee, but the effect was dependent on the intensity of the process. Cafestol and kahweol were degraded (general losses from 60 to 75 % on a lipid basis) to dehydrocafestol and dehydrokahweol, respectively, after 8 min of process, which corresponds to the commercial roasting degree. On the other hand, the amounts of cafestol and kahweol (mg/100 g of coffee) remained stable during the roasting process due to relative increase in lipid concentration.     

CO Oxidation Activity of a Au/Ceria-Zirconia Catalyst Prepared by Deposition�CPrecipitation with Urea

The activation of a 2.6 wt% Au/Ce_0.62Zr_0.38O₂ catalyst prepared by deposition?Cprecipitation with urea is investigated. At 298 K, the activity for CO oxidation of the as-prepared sample is very low; it is significantly increased when heated at 418 K, under the reaction mixture, and much strongly when pre-treated under flowing O₂(5%)/He, at 523 K. As revealed by XPS, FTIRS, HAADF-STEM, and HRTEM studies, the activation process consists of the transformation of the initial urea-containing Au(III) precursor deposited on the support into a highly dispersed metal phase (Au nano-particle mean size: 1.8 nm).     

Mycotic sinusitis

Previous drug discrimination studies have elucidated the importance of gamma-aminobutyric acidA (GABAA), N-methyl-D-aspartate (NMDA) glutamate, and serotonin (5-HT) receptor systems in mediating the discriminative stimulus effects of ethanol. The present study used a three-choice operant drug discrimination procedure in an attempt to determine if salient GABAergic effects could be separated from other stimulus effects of 2.0 g/kg ethanol. Adult male Long-Evans rats (n = 7) were trained to discriminate pentobarbital (10.0 mg/kg; intragastrically (i.g.) from ethanol (2.0 g/kg; i.g.) from water (4.7 ml; i.g.) using food reinforcement. Stimulus substitution tests were conducted following the administration of allopregnanolone (1.0-17.0 mg/kg; intraperitoneally (i.p.)), diazepam (0.1-7.3 mg/kg; i.p.), midazolam (0.0056-17.0 mg/kg; i.p.), dizocilpine (0.01-0.56 mg/kg; i.p.), phencyclidine (1.0-5.6 mg/kg; i.p.), CGS 12066B (3-30 mg/kg; i.p.), RU 24969 (0.1-5.6 mg/kg; i.p.) and morphine (1 or 3.0 mg/kg; i.p.). Within the group, allopregnanolone and midazolam completely substituted (> 80%), and diazepam partly substituted (67%) for the discriminative stimulus effects of pentobarbital. Dizocilpine and phencyclidine partly substituted (58 and 57%, respectively) for ethanol without substantial pentobarbital-appropriate responding. RU 24969, CGS 12066B and morphine did not result in complete substitution for either ethanol or pentobarbital, although RU 24969 resulted in partial (68%) pentobarbital substitution. The ability to train the present three-choice discrimination in rats indicates that the discriminative stimulus effects of 10.0 mg/kg pentobarbital were separable from those of 2.0 g/kg ethanol. The results suggest that the pharmacological effects of ethanol, which can control behavior, may seemingly be modified by training conditions (two-versus three-choice discrimination procedures), to the extent that a receptor system prominently linked to the behavioral activity of ethanol (i.e. GABAA) appears no longer to be involved in the interoceptive effects of the drug.     

Enhancement of dibenzothiophene biodesulfurization using β-cyclodextrins in oil-to-water media

It has been reported that biodesulfurization (BDS) of dibenzothiophene (DBT) in oil-to-water emulsions is carried out by growing cells of the aerobic Rhodococcus erythropolis IGTS8 strain and developing the so-called 4S desulfurization pathway. On adding β-cyclodextrins, it is possible to improve the BDS yields, increase the diffusion of DBT into the aqueous phase or avoid the HBP accumulation. Moreover, by using greater biocatalyst initial concentrations and adding 15 ppm of β-cyclodextrin, a very high BDS yield has been observed, but the presence of mass transfer limitations and the inhibition effects were not satisfactorily avoided. The Haldane kinetic model agreed well with the experimental results obtained, and the values of the kinetic parameters were determined.     

Stability evaluation of an immobilized enzyme system for inulin hydrolysis

The stability of free and Amberlite-immobilized inulinase, aiming at inulin hydrolysis was evaluated. The apparent activation energy of the biotransformation decreased when the immobilized biocatalyst was used, suggesting diffusional limitations, despite a decrease in the optimal temperature for catalytic activity for the immobilized biocatalyst. Thermal deactivation, of both forms of the biocatalyst, was evaluated by the linear inverted model. Inulinase immobilization consistently enhanced half-life of the enzyme, which increased up to 6-fold, as compared to the free form. Mean enzymatic activity was computed for both forms of the biocatalyst, and evidenced a decrease of optimal temperature with increased incubation periods. The deactivation energies estimated by an Arrhenius plot, evidenced a decrease of roughly 20% when free inulinase was used. The immobilized biocatalyst was effectively reused in successive batch runs for the hydrolysis of a 5% inulin solution.     

Gas–liquid mass transfer in oil–water emulsions with an airlift bio-reactor

Biodesulfurization reaction must be performed in oil–water emulsions with an aerobic biocatalyst which demands oxygen. Different reactor configurations can be used for this purpose, but the bubble column bio-reactors with internal recirculation loop are usually not used. In the present work, the absorption of oxygen in water–dodecane emulsions was studied in a bubble column bio-reactor with internal recirculation loop, in operative conditions normally used for biodesulfurization. The K_La for oxygen was determined for several organic fractions from 0 to 100%, as well as at different gas flow rates. Estimation of K_La was done according to a fluid dynamic model based on an energy balance which takes into account the energy dissipated at the interfaces and on a mass transfer model based on the fluid dynamic model, the Higbie's penetration theory and Kolmogoroff's theory of isotropic turbulence. Experimental data of mass transfer coefficient were simulated with satisfactory accuracy, and differences were less than 20% for most cases. Mayor deviations were obtained for emulsions with 30 and 70% dodecane fraction. To obtain good agreement, assumptions of higher bubble diameter and slip velocity were done, evincing the effect of surface tension and liquid viscosity on the mass transfer coefficient.     

Intestinal changes after jejuno-ileal shunt in obesity: a report of 2 cases

Two cases of end-to-end and end-to-side jejuno-ileal bypass for the treatment of obesity are reported in which both patients underwent reoperation 17 and 23 months later respectively. Macroscopic examination and measurements of length of the various segments of the small intestine have been performed twice in each patient: at the time of the bypass and at the second surgical procedure. In one patient a histological study of both the excluded and functioning small intestine was carried out at the time of each surgical procedure. The functioning intestine had increased in size while the excluded segment had become narrowed. The height of the villi had increased slightly in the functioning ileum and more so in the functioning jejunum compared with the preoperative measurements. In contrast, the height of the villi was moderately reduced in both the bypassed jejunal and ileal segments. These findings confirm the results of experimental studies in animals.     

Nitrogen solubilities in CaO—CaF2 melts

Nitrogen solubilities in the CaO—CaF₂ system were determined under controlled oxygen partial pressures as well as at carbon saturation. Nitrogen contents (as N^3?) were shown to strongly depend on oxygen partial pressure from 10^?11 to 10^?13 atm. At carbon saturation both nitride and cyanide contents are also dependent on oxygen partial pressure, i.e. CO partial pressure. The dependence of nitride and cyanide contents on nitrogen partial pressure was found to be compatible with the theory and is described by the equations proposed in this paper. The results are also discussed in terms of nitride and cyanide capacities for a better understanding of the dissolution of nitrogen in slags of different composition. The temperature dependence of nitride content showed an increase in nitride content with increasing temperature.