708 research outputs found

    Reaction of N,N-Dimethyltryptamine with Dichloromethane Under Common Experimental Conditions.

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    A large number of clinically used drugs and experimental pharmaceuticals possess the N,N-dimethyltryptamine (DMT) structural core. Previous reports have described the reaction of this motif with dichloromethane (DCM), a common laboratory solvent used during extraction and purification, leading to the formation of an undesired quaternary ammonium salt byproduct. However, the kinetics of this reaction under various conditions have not been thoroughly described. Here, we report a series of experiments designed to simulate the exposure of DMT to DCM that would take place during extraction from plant material, biphasic aqueous work-up, or column chromatography purification. We find that the quaternary ammonium salt byproduct forms at an exceedingly slow rate, only accumulates to a significant extent upon prolonged exposure of DMT to DCM, and is readily extracted into water. Our results suggest that DMT can be exposed to DCM under conditions where contact times are limited (<30 min) with minimal risk of degradation and that this byproduct is not observed following aqueous extraction. However, alternative solvents should be considered when the experimental conditions require longer contact times. Our work has important implications for preparing a wide-range of pharmaceuticals bearing the DMT structural motif in high yields and purities

    A Rational for Events: An Agenda for Change

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    This paper takes the position that the maturation of forensics as an activity tends to lead to the institutionalization of internal criteria which do not meet the assumptions others may hold about the goals of desirable programs of speech training. I believe the active pursuit of change for the sake of a dynamic, progressive enterprise is necessary to ensure the continued health, vitality and accepted legitimacy of this educational opportunity. Others may find virtue where I see vice: The continuing value of Individual Events for its participants is made manifest in most participants. However, as more departments decide to cut our budgets rather than some other area, and as more student governments seek to trim a budget of least essential items, we must question whether the qualities we desire are recognized by those who provide our ability to exist If those desired qualities are not clear to others, we must question the elements or conditions which make the communication of our goals difficult. To retain or regain our integral role in many institutions, we must discover the means to assert our essential function as communication educators providing students with important skills through a specialized form of instruction. We may wish to re-examine the degree to which our events reflect to those outside the activity the educational ends for which we strive

    Radio Survey of W UMa-type Systems

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    12 W~UMa-type systems were observed at 3.6 cm with a goal to compare their radio luminosities with those of non-contact, rapidly rotating, late-type stars. Only 3 systems, all of spectral type K, have been detected. The detections and (low) upper limits for remaining systems confirm the strong under-luminosity of W~UMa-type systems. VW~Cep, which was been detected several times before, has been analyzed in terms of the temporal cumulative flux distribution. Apparently, VW~Cep spends most of the time in radio quiescence with flare-like events taking less than 20\% of time.Comment: text, tables and 3 figures, all in PS, packed with uufile

    Dynamic Investigation of DNA Bending and Wrapping By Type II Topoisomerases

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    Elucidation of the Mechanism of an Epigenetic Switch by Single-molecule Assays

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    The Spatial Evolution of Particles Diffusing in the Presence of Randomly Placed Traps

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    The evolution of a particle undergoing a continuous-time random walk in the presence of randomly placed imperfectly absorbing traps is studied. At long times, the spatial probability distribution becomes strongly localized in a sequence of trap-free regions. The subsequent intermittent transfer of the survival probability from small trap-free regions to larger trap-free regions is described as a time-directed variable range hopping among localized eigenstates in the Lifshitz tail. An asymptotic expression for the configurational average of the spatial distribution of surviving particles is obtained based on this description. The distribution is an exponential function of distance which expands superdiffusively, with the mean-square displacement increasing with time as t2/ln(2D+4/D)(t) in D dimensions
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