Combustion of coal, bagasse and blends thereof Part II: Speciation of PAH emissions

This work reports on emissions of unburned hydrocarbon species from batch combustion of fixed beds of coal, sugar-cane bagasse, and blends thereof in a pre-heated two-stage laboratory furnace operated in the temperature range of 800-1000 degrees C. The effects of fuel blending, combustion staging, and operating furnace temperatures on emissions of pollutants were assessed. Furnace effluents were analyzed for products of incomplete combustion (PICs) including CO, volatile and semi-volatile hydrocarbons, and particulate matter, as has been reported in Ref. [1]. Emitted unburned hydrocarbons include traces of potentially health-hazardous Polycyclic Aromatic Hydrocarbons (PAHs), which are the focus of this work. Under the batch combustion conditions implemented herein, PAH were only generated during the volatile combustion phase of the fuels. The most prevalent species were in descending order: naphthalene, acenaphthylene, phenanthrene, fluoranthene, pyrene, dibenzofuran, benzofuran, byphenyl, fluorene, 9H-fluoren-9-one, acephenantrylene, benzo[b] fluoranthene, 1-methyl-naphthalene; 2-methyl-naphthalene, benz[a] anthracene and benzo[a] pyrene. PAH yields were the highest from combustion of neat bagasse. Combustion of the blends resulted in lower yields of PAH, than combustion of either of their neat fuel constituents. Increasing the furnace operating temperature enhanced the PAH emissions from bagasse, but had little effect on those from the coal or from the blends. Flue gas treatment in a secondary-stage furnace, upon with additional air, typically reduced PAH yields by promoting oxidation of the primary-stage furnace effluents. (C) 2011 Elsevier Ltd. All rights reserved.

Structural features of lignin obtained at different alkaline oxidation conditions from sugarcane bagasse

Lignin is a macromolecule frequently obtained as residue during technological processing of biomass. Modifications in chemical structure of lignin generate valuable products, some with particular and unique characteristics. One of the available methods for modification of industrial lignin is oxidation by hydrogen peroxide. In this work, we conducted systematic studies of the oxidation process that were carried out at various pHs and oxidizing agent concentrations. Biophysical, biochemical, structural properties of the oxidized lignin were analyzed by UV spectrophotometry, Fourier transform infrared spectroscopy, scanning electron microscopy and small angle X-ray scattering. Our results reveal that lignin oxidized with 9.1% H(2)O(2) (m/v) at pH 13.3 has the highest fragmentation, oxidation degree and stability. Although this processing condition might be considered quite severe, we have concluded that the stability of the obtained oxidized lignin was greatly increased. Therefore, the identified processing conditions of oxidation may be of practical interest for industrial applications. (C) 2011 Elsevier B.V. All rights reserved.

Possible implication of Mdm2 as a prognostic marker in invasive laryngeal carcinoma

Laryngeal squamous cell carcinoma is one of the most common malignant neoplasms of the head and neck. In Brazil, laryngeal tumors represent 2% of all cancers and are associated with approximately 3,000 deaths annually. Human papillomavirus (HPV) has been reported to play an important role in the etiology of laryngeal cancer. The aim of the present study was to evaluate the expression of p53, p27, and Mdm2 in laryngeal carcinomas. Sixty-three larynx biopsies were selected for the study, including 9 in situ laryngeal carcinomas, 27 laryngeal carcinomas without metastasis and 27 laryngeal carcinomas with metastasis. Twenty-seven cervical lymph nodes from patients with metastatic lesions were also evaluated. The expression levels of p53, p27, and Mdm2 were assessed by immunohistochemistry using a computer-assisted system. HPV detection and typing were performed using PCR, and the HPV types that were evaluated included HPV 6, 11, 16, 18, 31 and 33. Out of 63 patients, 53 (84.1%) were positive for beta-globin (internal control), and 10 (15.9%) were beta-globin negative and therefore excluded from the evaluation. Thus, 7 (13.2%) out of 53 patients were HPV positive, and 46 (86.8%) out of 53 patients were HPV negative. Statistically significant differences (p < 0.05) in Mdm2 expression levels were observed in the in situ laryngeal carcinoma samples compared with the laryngeal carcinoma samples with metastasis. No statistically significant differences (p > 0.05) in either p53 or p27 expression levels were detected. These findings suggest that Mdm2 may be associated with the invasiveness and aggressiveness of laryngeal carcinomas.

Estudo prospectivo comparativo de sistema especialista de prescrição médica na redução de erro e sobrecarga de trabalho médico

Erros médicos preveníveis(EMP) em hospitais excedem às mortes causadas por acidentes automobilísticos, câncer de mama e AIDS. O Institute of Medicine estima até 98.000 mortes causadas por EMP. O risco é aumentado quando os EMPs ocorrem em pacientes criticamente enfermos ou com medicações que variam com o peso do paciente. A demora da primeira prescrição é uma preocupação em UTI. Fadiga e sobrecarga podem comprometer a segurança numa UTI pediátrica. Objetivos: Comparar a funcionalidade de um Sistema Especialista(SE) experimental com a prescrição médica convencional Materiais/Métodos: Após termo de consentimento, pediatras de um hospital universitário são convidados a fazer a prescrição de 10 itens medicamentosos completos(soro de manutenção, adenosina, adrenalina, atropina, difenilhidantoína, vancomicina , ceftadizima, anfotericina_B, dobutamina, fentanil) para uma criança hipotética. Comparou-se a prescrição convencional com a prescrição feita no SE, após um treinamento prévio de 2 minutos. Uma equipe(médicos, enfermeiras e farmacêuticas) avaliaram os EMPs. Comparações feitas pelo X2, teste exato de fisher, teste t-student pareado ou Wilconson, quando aplicáveis. Significância considerada: p<0.05. Resultados:13 médicos residentes e 7 assistentes participaram do estudo com tempo médio de formação de 10,1+/-9 anos . Constatados 57 casos de EMP (9 ilegibilidades, 23 omissões, 6 erros de dose, 14 erros de diluição e 5 erros de velocidade de infusão) pela prescrição convencional comparado com 1 duplicação de medicação na prescrição por SE(p<0,001). O tempo médio de prescrição dos 10 medicamentos utilizando a abordagem ONE TOUCH do SE foi de 22,4 +/- 5,6 segundos_[13-36 segundos] e estava significantemente abaixo do tempo de prescrição convencional (média:557 +/- 164 segundos; p=0,00088). O tempo médio de prescrição com SE foi 27 vezes(IC95% 21,5- 32,5)) mais rápido que a convencional com economia de 89,1 minutos em uma UTI de 10 leitos. Conclusão:Embora não infalível, o uso de SE requer pouco tempo de treinamento e resulta em significante diminuição de erros e sobrecarga de trabalho.

Probing the statistical properties of unknown texts: application to the Voynich manuscript

While the use of statistical physics methods to analyze large corpora has been useful to unveil many patterns in texts, no comprehensive investigation has been performed on the interdependence between syntactic and semantic factors. In this study we propose a framework for determining whether a text (e.g., written in an unknown alphabet) is compatible with a natural language and to which language it could belong. The approach is based on three types of statistical measurements, i.e. obtained from first-order statistics of word properties in a text, from the topology of complex networks representing texts, and from intermittency concepts where text is treated as a time series. Comparative experiments were performed with the New Testament in 15 different languages and with distinct books in English and Portuguese in order to quantify the dependency of the different measurements on the language and on the story being told in the book. The metrics found to be informative in distinguishing real texts from their shuffled versions include assortativity, degree and selectivity of words. As an illustration, we analyze an undeciphered medieval manuscript known as the Voynich Manuscript. We show that it is mostly compatible with natural languages and incompatible with random texts. We also obtain candidates for keywords of the Voynich Manuscript which could be helpful in the effort of deciphering it. Because we were able to identify statistical measurements that are more dependent on the syntax than on the semantics, the framework may also serve for text analysis in language-dependent applications.