Metal complexing properties of water-soluble poly(N-maleyl glycine) studied by the liquid-phase polymer-based retention (LPR) technique

Summary The separation of various metal ions by the water-soluble N-maleyl glycine polymer in conjunction with membrane filtration was investigated. The method is based on the retention of inorganic ions by this polymer in a membrane filtration cell and subsequent separation of low-molecular-weight species from the polymer complex formed. It is shown that poly(N-maleyl glycine) can bind several metal ions in aqueous solution at pH 3. At higher pH, the water-soluble polymer can be applied to the separation and preconcentration of many metal ions. In addition, the maximum capacity values of the homopolymer for copper(II) were investigated and compared in the presence of various metal ions at different pHs.     

Renopancreatic transplant. Urologic complications

OBJECTIVE: Retrospective study of urological complications in our series of reno-pancreatic transplants. MATERIAL AND METHODS: Between February 1983 and May 1994 our group has conducted 93 RPT, 80 of which, mean age 36 +/- 6 years (24-54 years), are studied in this paper: 57 male and 23 female with an average time in dialysis of 20 +/- 15 months (0-84 months) and diabetes evolution of 21 +/- 5 years (11-37 years). RESULTS: Actuarial annual survival of patient, renal graft and pancreatic graft has been 85%, 79% and 74% respectively. Haematuria: 25% incidence, with graft pancreatitis etiology in 16 cases, rejection in 8 and urinary fistula in 6. Urinary infection: 85% incidence, symptomatic in 23 patients (29%) and asymptomatic in the remaining cases. Dysuria, urethritis and urethral stenosis: 14 patients, all male, most with both conditions associated. Reconversion of pancreatic exocrine secretion by intestinal route was performed in 7 patients. Urinary fistula: secondary to surgery in 9 cases and rejection in 4. Etiology of one case remained unknown. In 4 cases it was resolved with conservative treatment, and with surgical correction in 8. One patient required pancreatic transplantectomy and one patient died of AMI. CONCLUSIONS: Urological complication in RPT account for a significant morbidity, urinary fistula being the one with greater repercussion on the patient and pancreatic graft survival.     

Headspace methods for volatile components of cocoa butter

The suitability of dynamic headspace (DHS) method for isolating the volatile components of cocoa butter for subsequent GC analysis was evaluated. Volatile trapping followed by solvent or thermal desorption was performed with different adsorbent traps. DHS analysis by thermal desorption performed with Porapak Q showed the best results in terms of reproducibility and recovery of volatiles.     

Influence of cooking and drying processes at different temperatures on the nutritive value of the protein of mussels (Mytilus edulis)

The effect of steam cooking (96 degrees C for 15 minutes) and drying at two temperatures, 70 degrees C and 110 degrees C, on nutritive value of mussel protein was studied. The measurements were carried out by nitrogen balance techniques in growing rats, and the nutritional parameters studied were: CD, BV and NPU. The crude digestibility (CD) values were: 87 +/- 1 and 82 +/- 1, and the biological values (BV), 80 +/- 1 and 74 +/- 1 for raw mussels, dried at 70 degrees C and at 110 degrees C respectively. This implies a significant decrease in the protein nutritive values of the mussel dried at a higher temperature. Cooking prior to drying significantly improved the digestibility and the biological value of the mussel's protein. In effect, improvement was so great, that the different drying temperatures did not affect the previously cooked product in a different way; therefore, the CD (94 +/- 1 and 94 +/- 1) and the BV (90 +/- 1 and 90 +/- 2) were the same for the mussel's protein, cooked and dried at 70 degrees C or at 110 degrees C.     

Method for Measuring Short-Crack R-Curves without Calibration Parameters: Case Studies on Alumina and Alumina/Aluminum Composites

A method to measure short-crack R -curves is introduced which does not require an independent determination of calibration factors and which utilizes an equilibrium crack shape condition to compute the shape factor of a surface crack, R -curves of an alumina with two different grain sizes and of an aluminum/alumina composite were measured in the crack length regime of below 100 μm up to almost 1000 μm. Calculated and experimentally obtained crack depth profiles were in good agreement with deviations being between −22% and +26% for the crack ellipticity and confirmed the reliability of the method.     

Urban design and conflicting city images of Brazil: Rio de Janeiro and Curitiba

Imageability of places, cities and countries is strongly influenced by tourist and political portraits in the media. As human cognition relies on inferential perception and contrasting categories, marketing strategies exploit partial truths and conflicting city images to direct public perceptions. This article addresses the relationship between international perception, image building and urban design in the case of Brazil and the cities of Rio de Janeiro and Curitiba. Their contrasting images as exploited by the international media expose only partial truths. In fact, these images represent complementary development contradictions that co-exist in any major city today.     

Preparation of Phase-Pure M1 MoVTeNb Oxide Catalysts by Hydrothermal Synthesis—Influence of Reaction Parameters on Structure and Morphology

This work presents a detailed investigation of the preparation of MoVTeNbO _x catalysts by hydrothermal synthesis. Phase-pure synthesis of M1 has been achieved applying the metals in a molar ratio Mo/V/Te/Nb = 1/0.25/0.23/0.12. Raman, UV/Vis spectroscopy, and SEM/EDX analysis show that the elements are inhomogeneously distributed in the initial suspension that is formed after mixing the metal salts in an aqueous medium. Iso- and heteropoly anions of molybdenum, free telluric acid as well as supra-molecular polyoxometalate clusters are observed in the solution, whereas all metals have been found in the precipitate. Complete rearrangement of molecular building blocks under hydrothermal conditions is essential for formation of phase-pure materials. Optimized synthesis conditions with respect to temperature and time result in the formation of a precursor consisting of nano-structured M1 characterized by an extended periodic organization in the [001] direction and a fairly homogeneous distribution of the elements. Residual ammonium containing supra-molecular species in the precursor result in the formation of phase mixtures during the subsequent crystallization by heat treatment in inert gas. Phase-pure M1 exhibits a distinct degree of flexibility with respect to the chemical composition that becomes obvious by incorporating Nb not exclusively into pentagonal bi-pyramidal units, but also into octahedral coordinated positions as shown by EXAFS. Anisotropic growth of the needle-like M1 crystals has been observed during the final heat treatment performed at 873–923 K in inert atmosphere disclosing a potential method to control the catalytic properties of MoVTeNbO _x catalysts.