In the present study we aimed at investigating, for the first time, phenolic compounds in Brazilian beers of different types and styles. We also aimed at applying chemometrics for modeling beer's antioxidant capacity as a function of their physicochemical attributes (density, refractive index, bitterness and ethanol content). Samples (n=29) were analyzed by PCA originating five groups, especially according to ethanol contents and bitterness. In general, Group V (alcoholic beers with very high bitterness) presented higher refractive index, bitterness, ethanol and phenolics contents than Groups I (non-alcoholic beers) and II (alcoholic beers with low bitterness). Brazilian beers phenolics profile was distinct from that of European beers, with high contents of gallic acid (0.5-14.7 mg/L) and low contents of ferulic acid (0.2-1.8 mg/L). Using PLS, beer's antioxidant capacity measured by FRAP assay could be predicted with acceptable precision by data of ethanol content and density, bitterness and refractive index values.
Five hydrogen-oxidizing, thermophilic, strictly chemolithoautotrophic, microaerophilic strains, with similar (99-100 %) 16S rRNA gene sequences were isolated from terrestrial hot springs at Furnas, Sã o Miguel Island, Azores, Portugal. The strain, designated Az-Fu1T , was characterized.The motile, 0?9-2?0 mm rods were Gram-negative and non-sporulating. The temperature growth range was from 50 to 73 6C (optimum at 68 6C). The strains grew fastest in 0?1 % (w/v) NaCl and at pH 6, although growth was observed from pH 5?5 to 7?0. Az-Fu1 T can use elemental sulfur, sulfite, thiosulfate, ferrous iron or hydrogen as electron donors, and oxygen (0?2-9?0 %, v/v) as electron acceptor. Az-Fu1 T is also able to grow anaerobically, with elemental sulfur, arsenate and ferric iron as electron acceptors. The Az-Fu1 T G+C content was 33?6 mol%.Maximum-likelihood analysis of the 16S rRNA phylogeny placed the isolate in a distinct lineage within the Aquificales, closely related to Sulfurihydrogenibium subterraneum (2?0 % distant). The 16S rRNA gene of Az-Fu1 T is 7?7 % different from that of Persephonella marina and 6?8 % different from Hydrogenothermus marinus. Based on the phenotypic and phylogenetic characteristics presented here, it is proposed that Az-Fu1 T belongs to the recently described genus Sulfurihydrogenibium. It is further proposed that Az-Fu1 T represents a new species, Sulfurihydrogenibium azorense.
PurposeWe evaluated the effect of different water immersion (WI) temperatures on post-exercise cardiac parasympathetic reactivation.MethodsEight young, physically active men participated in four experimental conditions composed of resting (REST), exercise session (resistance and endurance exercises), post-exercise recovery strategies, including 15 min of WI at 15°C (CWI), 28°C (TWI), 38°C (HWI) or control (CTRL, seated at room temperature), followed by passive resting. The following indices were assessed before and during WI, 30 min post-WI and 4 hours post-exercise: mean R-R (mR-R), the natural logarithm (ln) of the square root of the mean of the sum of the squares of differences between adjacent normal R–R (ln rMSSD) and the ln of instantaneous beat-to-beat variability (ln SD1).ResultsThe results showed that during WI mRR was reduced for CTRL, TWI and HWI versus REST, and ln rMSSD and ln SD1 were reduced for TWI and HWI versus REST. During post-WI, mRR, ln rMSSD and ln SD1 were reduced for HWI versus REST, and mRR values for CWI were higher versus CTRL. Four hours post exercise, mRR was reduced for HWI versus REST, although no difference was observed among conditions.ConclusionsWe conclude that CWI accelerates, while HWI blunts post-exercise parasympathetic reactivation, but these recovery strategies are short-lasting and not evident 4 hours after the exercise session.
: Porous hydroxyapatite (HA) has already been widely used as a bone substitute due to its similarity with the mineral part of the bone. In this work, cylindrical tablets with micro and macro porosity were produced from stoichiometric and deficient hydroxyapatites by using naphthalene as porosifier agent. The influence of the processing parameters such as Ca/P ratio of start material, calcination temperature, and naphthalene content on the characteristics of porous calcium phosphate tablets was evaluated. Three mineral phases—HA, α‐TCP (α tri‐calcium phosphate), and β‐TCP (β tricalcium phos‐phate)—with variable contents were identified by x‐ray diffraction (XRD) and Fourier‐transformed infrared spectroscopy (FT‐IR). Image analysis and density measurements were used to characterize sample porosity. As expected, the total porosity of the calcinated material is not dependent on the stoichiometry of the precursor hydroxyapatite. For calcium‐deficient hydroxyapatite, the increase in naphthalene content contributes to stabilize α‐TCP phase, altering the relative phases content.
Recebido em 26/2/07; aceito em 14/6/07; publicado na web em 14/1/08 DETERMINATION OF BIODIESEL PERCENTAGE IN BIODIESEL:DIESEL MIXTURES USING MID-INFRARED SPECTROSCOPY. Considered the best substitute for diesel, biodiesel can be blended with diesel in any ratio, bringing lots of environmental, economic and social advantages. Brazilian law Nº 11097/2005, proposes the introduction of biodiesel in to the Brazilian energy matrix, mixed with diesel at a minimum percentage of 2%. For consumers and sellers to be sure that the commercialized mixture of biodiesel:diesel contains the correct percentage, it is necessary to develop analytical methodologies to quantify the amount of biodiesel added. This work presents a fast, low-cost and simple methodology to determine the biodiesel proportion in mixtures of biodiesel:diesel, based on infrared spectroscopy.Keywords: biodiesel; biodiesel:diesel mixtures; mid-infrared spectroscopy.
INTRODUÇÃOA possibilidade de uso de óleos vegetais como combustível foi reconhecida desde os primórdios dos motores diesel. O próprio Rudolph Diesel utilizou vários óleos vegetais em seus motores e no prefácio escrito por ele para o livro Termodinâmica, de Chalkey (1911), afirmou: "O motor diesel pode ser alimentado com óleos vegetais e poderá ajudar consideravelmente o desenvolvimento da agricultura nos países onde ele funcionar. Isso parece um sonho do futuro, mas eu posso predizer com inteira convicção que esse modo de emprego do motor diesel pode, em dado tempo, adquirir uma grande importância" 1 . Os derivados de óleos vegetais são substitutos adequados para o óleo diesel por não requererem modificações nos motores e apresentarem alto rendimento energético. Eles não contêm enxofre (portanto, não contribuem para geração de ácido sulfuroso na atmosfera -chuva ácida) e sua combustão gera menores teores de gases poluentes que o óleo diesel, pois retiram CO 2 da atmosfera para crescimento da planta e a quantidade de CO 2 liberada na combustão desses óleos é menor que a gasta na sua produção. Por isso, o uso de biodiesel de origem vegetal reduz o percentual de CO 2 , um gás de efeito estufa, na atmosfera 2 . A alternativa mais viável de transformação dos óleos vegetais para gerar um combustível capaz de fazer funcionar um motor por compressão sem danificá-lo tem sido o biodiesel. Considerado um combustível biodegradável e ambientalmente correto, o biodiesel quimicamente é uma mistura de ésteres mono-alquílicos de ácidos graxos 3
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