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Study of Brazilian Woods Using Gamma-Ray Sources

Journal of Physical Science and Application 2014年第5期4卷 304-309页

作者： gilberto carvalho leonardo gondim de andrade e silva Radiation Technology Centre Nuclear and Energy Research Institute National Nuclear Energy Commission (IPEN-CNEN/SP Sao Paulo 05508-000 Brazil

Due to the availability and particular features, wood was one of the first materials used by mankind with a wide variety of applications. It can be used as raw-material for paper and cellulose manufacturing; in industries such as chemical, naval, furniture, sports goods, toys, and musical instruments; in building construction and in the distribution of electric energy. Wood has been widely researched; therefore, wood researchers know that several aspects such as temperature, latitude, longitude, altitude, sunlight, soil, and rainfall index interfere as to the growth of trees. This behavior explains why the average of physical chemical properties is important in wood *** of the researchers consider density to be the most important wood property because of its straight relationship with the physical and mechanical properties in wood. There are three types of wood density： basic, apparent and green. The apparent density was used here at 12% of moisture content. In this study, four different types of wood were used：＂Freijo＂, ＂Jequitiba＂, ＂Muiracatiara＂ and ＂Ipe＂. For wood density determination by non-conventional method, ^241Am, ^133Ba and ^137Cs gamma-ray sources, a NaI scintillation detector and a counter were used. The results demonstrated that this technique is quick and accurate. Considering the nuclear parameters obtained as half-value layers and linear absorption coefficients,^ 137Cs demonstrated to be the best option to be used for inspection of the physical integrity of electric wooden poles and live trees for future works.

关键词： Brazilian woods density gamma-ray.

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Chemical Characterization,Antibacterial and Antioxidant Activities of essential Oils of Mentha viridis *** Mentha pulegium L.(L)

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American Journal of Plant Sciences 2015年第5期6卷 666-675页

作者： Lucilene Fernandes silva Maria das Gracas Cardoso Luís Roberto Batista Marcos de Souza Gomes leonardo Milani Avelar Rodrigues Danúbia A.de carvalho Selvati Rezende Maria Luisa Teixeira Marcos Schleiden Sousa carvalho Juliana de andrade Santiago David Lee Nelson department of Chemistry Federal University of Lavras Lavras Brazil department of Food Science Federal University of Lavras Lavras Brazil department of Agriculture Federal University of Lavras Lavras Brazil Federal University of Vales de Jequitinhonha e Mucuri Diamantina Brazil

The essential oils from Mentha viridis L. and Mentha pulegium L. were characterized by gas chromatography coupled to mass spectrometry (GC-MS). These oils were obtained by hydrodistillation and presented linalool (40.70%), carvone (13.52%) and α-terpinene (8.56%) as the principal constituents in the essential oil from Mentha viridis L. Pulegone (50.01%), menthol (31.90%) and menthone (16.56%) were the principal constituents in the essential oil from Mentha pulegium L. These essential oils (in concentrations ranging from 3.91 to 500 μL·mL-1) showed satisfactory activities against escherichia coli, Listeria monocytogenes, Salmonella choleraesuis and Staphylococcus aureus. The antioxidant activities with 2-deoxyribose and phosphomolybdenum and the reducing power (in concentrations ranging from 0.78 to 1000 μL·mL-1) were determined. The antioxidant activity was observed for the two oils evaluated by the phosphomolybdenum and 2-deoxyribose methods, whereas the essential oil from M. viridis presented low antioxidant activity in the reducing power assay.

关键词： Mentha Linalool Pulegone Volatiles

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