The role of micro-ribonucleic acids in normal hematopoiesis and leukemic T-lymphogenesis

Micro-ribonucleic acids (microRNAs) are small molecules containing 20-23 nucleotides. Despite their small size, it is likely that almost every cellular process is regulated by them. Moreover, aberrant microRNA expression has been involved in the development of various diseases, including cancer. Although many data are available about the role of microRNAs in various lymphoproliferative disorders, their impact on the development of acute lymphoblastic leukemia of T-cell progenitors is largely unknown. In this review, we present recent information about how specific microRNAs are expressed and regulated during malignant T-lymphopoiesis and about their role during normal hematopoiesis.

Improved biological performance of magnesium by micro-arc oxidation

Magnesium and its alloys have recently been used in the development of lightweight, biodegradable implant materials. However, the corrosion properties of magnesium limit its clinical application. The purpose of this study was to comprehensively evaluate the degradation behavior and biomechanical properties of magnesium materials treated with micro-arc oxidation (MAO), which is a new promising surface treatment for developing corrosion resistance in magnesium, and to provide a theoretical basis for its further optimization and clinical application. The degradation behavior of MAO-treated magnesium was studied systematically by immersion and electrochemical tests, and its biomechanical performance when exposed to simulated body fluids was evaluated by tensile tests. In addition, the cell toxicity of MAO-treated magnesium samples during the corrosion process was evaluated, and its biocompatibility was investigated under in vivo conditions. The results of this study showed that the oxide coating layers could elevate the corrosion potential of magnesium and reduce its degradation rate. In addition, the MAO-coated sample showed no cytotoxicity and more new bone was formed around it during in vivo degradation. MAO treatment could effectively enhance the corrosion resistance of the magnesium specimen and help to keep its original mechanical properties. The MAO-coated magnesium material had good cytocompatibility and biocompatibility. This technique has an advantage for developing novel implant materials and may potentially be used for future clinical applications.

Reconocimiento de alimentos vegetales: caracterización micro-gráfica del grano de avena

Se estudia la estructura micrográfica del grano de seis variedades de avena con la finalidad de su caracterización, para desarrollar parámetros de identificación en alimentos elaborados con la misma y, consecuentemente, determinar su autenticidad, contribuyendo a optimizar la producción, la comercialización y el consumo del cereal y sus derivados. El diseño experimental consistió en el estudio micrográfico de los granos vestidos y desnudos efectuando un análisis morfológico mediante observación con lupa binocular y fotografía, ultraestructural utilizando microscopio electrónico de barrido, micrográfico y micrométrico, empleando el sistema de video microscopia digitalizado y software adecuado. Dada su variabilidad natural, los estudios se efectuaron durante tres temporadas consecutivas sobre muestras cosechadas de variedades procedentes de cultivos de semillas certificadas, y sobre alimentos procesados (avena arrollada y salvado de avena comerciales). Los resultados consistieron en diseños micrográficos, y en valores micrométricos de gránulos de almidón relacionados, además, en modelos matemáticos. En todos los casos se validó estadísticamente. Como parámetros micrográficos de caracterización se seleccionaron las estructuras diferenciales, que revelaron una presencia constante en el vegetal y resistieron los tratamientos tecnológicos, y las características y dimensiones del almidón.

Tratamento térmico do amido de batata-doce (Ipomoea batatas L.) sob baixa umidade em micro-ondas

O objetivo deste trabalho foi avaliar o efeito do tratamento térmico sob baixa umidade (TTBU) aplicado por forno micro-ondas sobre as propriedades estruturais e funcionais do amido de batata-doce e compará-las com as propriedades de amido tratado pelo método convencional. O amido extraído dessa raiz foi submetido à modificação física, nas umidades de 25 e 35%, em forno convencional (90 °C/16 horas) e em microondas (35 a 90 °C/1 hora). O tratamento térmico sob baixa umidade resultou em alterações significativas no teor de amilose e em características como a cristalinidade, suscetibilidade enzimática, fator de expansão e propriedades de pasta. Tais variações evidenciam modificações na estrutura granular interna dos amidos, tanto em áreas cristalinas como amorfas do grânulo. As alterações conferidas pelo TTBU foram variáveis com o tipo de tratamento térmico e com o teor de umidade. A umidade das amostras também foi determinante na modificação da maioria das características do amido, como maior digestibilidade enzimática e redução da expansão, menores picos de viscosidade e quebras de viscosidade, independentemente do tipo de tratamento térmico aplicado. Considerando-se o tipo e a intensidade da modificação física do amido tratado pelo método convencional como referência, a utilização da energia de micro-ondas para esse mesmo fim precisa ser melhor estudada.

Head Space Solid Phase Micro-Extraction (HS - SPME) of volatile organic compounds produced by Sporidiobolus salmonicolor (CBS 2636)

The aim of the present study was the assessment of volatile organic compounds produced by Sporidiobolus salmonicolor (CBS 2636) using methyl and ethyl ricinoleate, ricinoleic acid and castor oil as precursors. The analysis of the volatile organic compounds was carried out using Head Space Solid Phase Micro-Extraction (HS - SPME). Factorial experimental design was used for investigating extraction conditions, verifying stirring rate (0-400 rpm), temperature (25-60 ºC), extraction time (10-30 minutes), and sample volume (2-3 mL). The identification of volatile organic compounds was carried out by Gas Chromatography with Mass Spectrum Detector (GC/MSD). The conditions that resulted in maximum extraction were: 60 ºC, 10 minutes extraction, no stirring, sample volume of 2.0 mL, and addition of saturated KCl (1:10 v/v). In the bio-production of volatile organic compounds the effect of stirring rate (120-200 rpm), temperature (23-33 ºC), pH (4.0-8.0), precursor concentration (0.02-0.1%), mannitol (0-6%), and asparagine concentration (0-0.2%) was investigated. The bio-production at 28 ºC, 160 rpm, pH 6,0 and with the addition of 0.02% ricinoleic acid to the medium yielded the highest production of VOCs, identified as 1,4-butanediol, 1,2,2-trimethylciclopropilamine, beta-ionone; 2,3-butanodione, pentanal, tetradecane, 2-isononenal, 4-octen-3-one, propanoic acid, and octadecane.

Os determinantes empíricos da felicidade no Brasil

This paper investigates the role that economic variables play in the determination of happiness, using reported happiness as a proxy to individual well-being. We use microdata extracted from the World Values Survey for five countries, emphasizing the Brazilian case. Our findings suggest that there is a positive and significant correlation between happiness and income. Unemployment is also a large source of unhappiness. In most cases, happiness appears to be positively correlated to being married. Moreover, happiness is apparently U-shaped in age (minimizing at 50's).

Determinantes da recuperação do emprego formal no Brasil: evidências para o período 2001/2005 e hipoteses para uma agenda de pesquisa

Decisive factors affecting the recent increase in formal employment in Brazil. This paper gives a general overview of the evolution of labour market indicators between 1995 and 2005 in Brazil. It shows an overall increase in formal employment rates from 2001 to 2005, as opposite to what had happened from 1995 to 1999. It is argued that such recent trends might indicate the reconfiguration of the labour market in better terms, with potential positive consequences to the finance performance of the Social Security sector. The paper also examines some of the major factors associated with this new trend and their chances to maintain such tendency in the near future. It's important to notice that all of them may be subject to some kind of political management by the State. In other words, we suggest that there are suficient instruments and operative skills in the Brazilian State to make these and others factors work in favour of a more persistent strategy of development with social inclusion through labour.

Fatores comuns determinantes de crises cambiais e financeiras

Determinative common factors of currency and financial crisis. This paper identifies and evaluates determinative common factors of currency and financial crisis in relation to 86 crises episodes between 1970-2004, based on factor analysis, cluster and discriminant analysis. One evidenced that the rise of the ratios of domestic credit, fiscal deficit and residents bank deposits to the GDP is inherent to the different types of crises classified for economic literature. It was also identified as common factors to these episodes some indicators that capture the excessive monetary expansion of the economies and that reflect the fall in international reserves, represented by M2/Reserves and Imports/Reserves ratios and also the total volume of international reserves.

Finance-Led Growth Regime no Brasil: estatuto teórico, evidências empíricas e consequências macroeconômicas

This paper analyzes the Brazilian growth pattern during the post-liberalization period, emphasizing the structural links between finance and productive capital accumulation. The results indicate a finance-led growth regime in the period 2004-2008, under a very specific financialization process. The first part is a survey of the international literature, which defines the financialization concept and its relevance for understanding Brazilian economic problems. The next part provides a historical overview on the structural changes that made possible the development of financial-led regimes. The paper also applies an empirical analysis of some selected Brazilian macroeconomic indicators.