Sequential Fragmentation
Mostrando 1-10 de 10 artigos, teses e dissertações.
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1. Aplicação da química quântica computacional no estudo de processos químicos envolvidos em espectrometria de massas
The field of application of mass spectrometry (MS) has increased considerably due to the development of ionization techniques. Other factors that have stimulated the use of MS are the tandem mass spectrometry (MS/MS) and sequential mass spectrometry (MSn) techniques. However, the interpretation of the MS/MS and MSn data may lead to speculative conclusions. T
Química Nova. Publicado em: 2008
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2. CONSTITUINTES VOLÁTEIS E ATIVIDADE ANTIMICROBIANA DE Senecio crassiflorus (Poir.) DC. var. crassiflorus / VOLATILE CONSTITUENTS AND ANTIMICROBIAL ACTIVITY OF Senecio crassiflorus (Poir.) DC. var. crassiflorus
Several Senecio species (Asteraceae) have been used in folk medicine for the treatment of infections. This genus is rich in a wide variety of secondary metabolites such as alkaloids, flavonoids, and terpenoids with recognized antimicrobial activity. Senecio crassiflorus (Poir.) DC. var. crassiflorus, commonly known as margarida-das-dunas, is native from the
Publicado em: 2007
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3. FRAGMENTAÇÃO DA MOLÉCULA DE ÁGUA POR IMPACTO DE ÍONS DE HE(+) / WATER MOLECULE FRAGMENTATION BY IMPACT OF HE(+) ions
Neste trabalho são apresentadas, pela primeira vez, seções de choque absolutas para a ionização e a fragmentação da molécula de vapor d´água em colisões com He(+), para as energias de 1,0, 1,5 e 2,0 MeV, totais e parciais nos processos de ionização pura, perda eletrônica (ionização do projétil) e captura eletrônica pelo projétil. Essas se�
Publicado em: 2006
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4. Optimization procedures for establishing reserve networks for biodiversity conservation taking into account population genetic structure
Conservation genetics has been focused on the ecological and evolutionary persistence of targets (species or other intraspecific units), especially when dealing with narrow-ranged species, and no generalized solution regarding the problem of where to concentrate conservation efforts for multiple genetic targets has yet been achieved. Broadly distributed and
Genetics and Molecular Biology. Publicado em: 2006
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5. Comparison between models of the decay of light compound nuclei
The decay of the compound nucleus is traditionally calculated using one of two types of statistical models, either a sequential or a simultaneous emission one. The best known sequential emission models are the Weisskopf-Ewing one and the Hauser-Feshbach one. Both sequential emission models emit only one particle at a time. A well know simultaneous emission m
Brazilian Journal of Physics. Publicado em: 2005-09
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6. Syntheses of all singly labeled [15N]adenines: Mass spectral fragmentation of adenine
Syntheses of all five of the singly labeled [15N]adenines are now provided. The presence or absence of two-bond 15N-1H spin couplings in their 1H NMR spectra confirm the location of the isotope in each case. The fragmentation patterns in their mass spectra are indicative of the sequential losses of HCN units and of CH2N2 from adenine upon electron impact.
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7. Sequential excision of internal eliminated DNA sequences in the differentiating macronucleus of the hypotrichous ciliate Stylonychia lemnae.
Elimination of internal eliminated sequences (IES) during macronuclear development of the hypotrichous ciliate Stylonychia lemnae was analyzed in one cluster of macronuclear precursor DNA sequences. The results indicate that IES elimination is a highly ordered process, it starts very early during macronuclear development and has only finished immediately bef
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8. Portable System for Microbial Sample Preparation and Oligonucleotide Microarray Analysis
We have developed a three-component system for microbial identification that consists of (i) a universal syringe-operated silica minicolumn for successive DNA and RNA isolation, fractionation, fragmentation, fluorescent labeling, and removal of excess free label and short oligonucleotides; (ii) microarrays of immobilized oligonucleotide probes for 16S rRNA i
American Society for Microbiology.
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9. Effect of Chemical Modification and Fragmentation on Antigenic Determinants of Internal Protein p30 and Surface Glycoprotein gp70 of Type C Retroviruses
The effects of protein modification on the antigenic determinants of p30 and gp70 of type C retroviruses were investigated by using solid-phase competition radioimmunoassays. Proteins were modified by reduction with 2-mercaptoethanol and subsequent carboxymethylation of SH groups with iodoacetamide or by amidination of α and ε amino groups with methylaceti
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10. The two-step conversion of big endothelin 1 to endothelin 1 and degradation of endothelin 1 by subcellular fractions from human polymorphonuclear leukocytes.
The metabolism of big endothelin 1 (bET) and endothelin 1 (ET-1) by subcellular fractions from human polymorphonuclear leukocytes (PMNs) was investigated by bioassay and reversed-phase high-performance liquid chromatography. More than 80% of endothelin-converting activity was recovered from the cytosolic fraction, which in addition to ET-1 generated other pe