RESUMO
Slowly compressed microcrystals deform via intermittent slip events, observed as displacement jumps or stress drops. Experiments often use one of two loading modes: an increasing applied stress (stress driven, soft), or a constant strain rate (strain driven, hard). In this work we experimentally test the influence of the deformation loading conditions on the scaling behavior of slip events. It is found that these common deformation modes strongly affect time series properties, but not the scaling behavior of the slip statistics when analyzed with a mean-field model. With increasing plastic strain, the slip events are found to be smaller and more frequent when strain driven, and the slip-size distributions obtained for both drives collapse onto the same scaling function with the same exponents. The experimental results agree with the predictions of the used mean-field model, linking the slip behavior under different loading modes.
RESUMO
A fully automated nucleic acid analysis system is described, which offers positive sample identification, improved sensitivity and reduced user interaction compared to conventional techniques. The system relies on the sequence-specific capture of DNA onto solid-phase particles, confirming product identity without the problems of interpretation and lack of sequence information inherent in gel-based analyses. The system can be used for sequence confirmation, mutation analysis and semiquantitative detection of PCR products.
Assuntos
Ácidos Nucleicos/análise , Automação , Biotinilação , Análise Mutacional de DNA/métodos , Primers do DNA , Microesferas , Oligonucleotídeos/análise , Reação em Cadeia da Polimerase , Sensibilidade e Especificidade , Análise de Sequência/métodosAssuntos
Óxido de Etileno/administração & dosagem , Proteínas/efeitos dos fármacos , Carcinógenos Ambientais/administração & dosagem , Carcinógenos Ambientais/metabolismo , DNA/efeitos dos fármacos , DNA/metabolismo , Relação Dose-Resposta a Droga , Monitoramento Ambiental , Óxido de Etileno/metabolismo , Cromatografia Gasosa-Espectrometria de Massas , Humanos , Imunoquímica , Proteínas/metabolismoRESUMO
A novel immunochemical approach has been developed to monitor human exposures to ethylene oxide (EO). The method exploits the interaction of EO with the amino function of the N-terminal valine residue of the alpha-chain of human haemoglobin (Hb). Antibodies were raised against the adducted valine in the form of the N-terminal tryptic heptapeptide and have been used to develop a sensitive radioimmunoassay (RIA) for the adducted heptapeptide. This method has been fully validated against a gas chromatography-mass spectrometry (GC-MS) method and has been applied to the monitoring of EO exposure in a group of sterilization workers.
