A study was made of the kinetics of sunflower oil methanolysis. This reaction yields methyl esters (biodiesel) and glycerol and consists of three consecutive reversible reactions. Diglycerides and monoglycerides are intermediate products. A reaction mechanism was proposed involving an initial region of mass transfer control followed by a second region of kinetical control. An analysis was also made of the effects of impeller speed, temperature, and catalyst concentration on the reaction rates, determining the reaction rate constants and the activation energies. The reactions were performed in a batch stirrer reactor, and the reaction mixture was analyzed by gas chromatography. The initial mass transfer-controlled region was not significant using 600 rpm. The kinetically controlled section followed a second-order mechanism for the forward and reverse reactions, where the reaction system could be described as a pseudo-homogeneous catalyzed reaction. The temperature and catalyst concentration increased the reaction rates. The proposed mathematical model fitted the experimental results well.

In children, cervical lymphadenitis is the most common type of infection caused by non-tuberculous mycobacteria. The isolated species are frequently identified as M. avium, M. scrofulaceum, and M. malmoense; they often cause indolent cervical adenitis and the treatment of choice is radical excision. [1][2][3][4] In recent times, new mycobacteria species have been described: M. lentiflavum, M. interjectum, which cause lymphadenitis in children as in the case presented here. [1][2][3][4][5][6] A 2-year-old boy presented with a 3-month history of a 2 Â 2 cm submandibular adenopathy in the right cervical area, which did not remit with antibiotic treatment (amoxicillin-clavulanate). On examination, a tumor was found in the right submandibular region, which was indolent, fluctuant, inflamed and with a high temperature.The patient had not received a BCG vaccination and tested positive (14 mm) on the PPD RT-23 2 TU Mantoux tuberculin test. In blood screening most noteworthy was: Leucocytes 9500 (37% neutrophyles, 49% lymphocytes, and 10% monocytes) and a globular sedimentation rate of 62.In the neck ultrasound examination, in the right submandibular region, a small irregular lump was appreciated, which went from the adenopathy with necrosis to the surface of the skin.Due to suspicion of tuberculous adenopathy, treatment was initiated with rifampicin, isoniazid, and pyrazinamide for 9 months.The drainage liquid of the adenopathy was sent to the laboratory resulting in negative staining and cultures. The remitted sample was decontaminated using the N-acetyl-L-cysteine-NaOH method, it was cultured in a Löwenstein-Jensen medium and inoculated in a liquid medium BACTEC MGIT 960 System (Mycobacteria growth indicator tube: Becton Dickinson, Heidelberg, Germany). After 4 weeks of incubation in the liquid medium, a scotochromogenic mycobacteria grew which was sent to the National Microbiology Centre of Majadahonda for its molecular typing and antimicrobial sensibility.The isolate was identified by phenotipic and genotypic methods. We performed a subculture on Löwenstein-Jensen and observed smooth colonies of about 1-2 mm in diameter, with bright yellow pigmentation after 3 weeks of incubation at 378C. The growing was inhibited at 22 and 428C. The majority of the biochemical tests were negative (niacin production, Tween-80 hydrolysis, tolerance for NaCl 5%, nitrate reductase, arylsulfatase, and urease). Only two tests were positive, the tellurite reduction and weakly the heat-stable catalase test. The genetic studies were performed by PCR-RFLP of hsp65 gene. 7 The analyzed strain showed two fragments (sized 240 and 210 bp) and two fragments (sized 130 and 110 bp) by BstEll and Haell restriction enzyme digestion, respectively. The size of the fragments corresponds to M. Interjectum.The identification was confirmed by sequencing of 16S rRNA gen. The DNA sequence of the 1,514 bp 16S rRNA region was amplified using the primer described by Springer et al. 8 The PCR conditions were those described previously by Kirschner et al. 9 The se...

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