Videomicroscopy was used to observe dynamic behavior accompanying phase transformation in waternonionic surfactant mixtures and the contact of these mixtures with pure hydrocarbons. Various unusual phenomena involving growth and dissolution of the lamellar liquid crystalline phase were seen, including the formation of myelinic figures and bâtonnets by the novel procedure of heating an isotropic liquid. In some phenomena the defect structure of the liquid crystalline phase played a controlling role. For instance, initial nucleation of fluid phases was seen to occur along defects, the first such observation for liquid crystals. Various types of behavior were seen in the contacting experiments, depending on whether the temperature was well below, near, or well above the phase inversion temperature. The chief phenomena, spontaneous emulsification and intermediate phase formation, were similar in many respects to those seen previously in anionic surfactant systems and were explainable in terms of diffusion path theory. In several experiments flow produced by natural convection and/or Marangoni effects increased the rate of equilibration and was the source of rather dramatic behavior. 相似文献
Currently, all assays measuring acetylcholinesterase (AChE) activity following a suspected nerve agent exposure leverage methodologies that fail to identify the agent. This limits the overall effectiveness and ability to administer proper countermeasures. As such, there is an urgent need to identify novel, rapid, and more comprehensive approaches to establish AChE activity, including identification of the toxicant. Paper spray mass spectrometry was used to monitor the activity of acetylcholinesterase, both in-solution and on modified hydrophobic paper surface. Hydrophobic paper surfaces were prepared using vaporized trichloro(3,3,3-trifluoropropyl)silane. In both approaches, mixtures of diluted human whole blood with and without VX were mixed with a non-endogenous AChE specific substrate, 1,1-dimethyl-4-acetylthiomethylpiperidinium (MATP+). Formation of the cleaved MATP+ product was monitored over time and compared to MATP+ to determine relative AChE activity. This on-substrate assay was effective at determining AChE activity and identifying the toxicant; however, determination of AChE activity in-solution proceeded at a slower rate. The on-substrate assay serves as a pioneering example of an enzymatic reaction occurring on the surface of a paper spray ionization ticket. This work broadens the range of applications relating to paper spray ionization-based clinical diagnostic assays.
