13,352 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

    Ratchet Effects for Vortices in Superconductors with Periodic Pinning Arrays

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    Using numerical simulations we show that novel transport phenomena can occur for vortices moving in periodic pinning arrays when two external perpendicular ac drives are applied. In particular, we find a ratchet effect where the vortices can have a net dc drift even in the absence of a dc drive. This ratchet effect can occur for ac drives which create orbits that break one or more reflection symmetries.Comment: 4 pages, 4 postscript figures; Proceedings of Third European Conference on Vortex Matter in Superconductor

    Multiple Out-Of-Home Placements & Children\u27s Psychosocial Functioning

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    This study examined the relationship between multiple out-of-home placements and children’s psychosocial functioning. Psychosocial functioning was measured by the number of mental health services recommended to the child by a licensed mental health professional and the number of negative behaviors exhibited by the child as recorded in the caseworkers’ narratives or mental health professional’s report. Independent variables included total number of placements experienced per child and average placement duration. Data were extracted from the administrative database and case files of the State of Nebraska Foster Care Review Board Tracking System (N=443). In addition to the number of out-of-home placements and measures of psychosocial functioning, demographic information, entry-level measures and organizational measures were obtained. To control for the subjectivity of the data, this study examined that information believed to be valid and reliable either based on its simplicity (demographics), because it was required by governmental standards (entry- level factors), or because it was provided by a licensed mental health professional (assessment information). All information was cross-referenced against case narratives. This study utilized multiple hierarchical regression analyses to analyze the data. Results indicated that when controlling for demographic and entry-level factors, children who experienced more out-of-home placements received recommendations for more mental health services and were reported to exhibit more negative behaviors. Average Placement Duration did not account for any additional variance in these two outcomes. The overall findings are consistent with the contention that multiple out-of-home placements have a negative impact on children’s psychosocial functioning

    Computational Design and Characterization of a Temperature-Sensitive Plasmid Replicon for Gram Positive Thermophiles

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    Temperature-sensitive (Ts) plasmids are useful tools for genetic engineering, but there are currently none compatible with the gram positive, thermophilic, obligate anaerobe, Clostridium thermocellum. Traditional mutagenesis techniques yield Ts mutants at a low frequency, and therefore requires the development of high-throughput screening protocols, which are also not available for this organism. Recently there has been progress in the development of computer algorithms which can predict Ts mutations. Most plasmids currently used for genetic modification of C. thermocellum are based on the replicon of plasmid pNW33N, which replicates using the RepB replication protein. To address this problem, we set out to create a Ts plasmid by mutating the gene coding for the RepB replication protein using an algorithm designed by Varadarajan et al. (1996) for predicting Ts mutants based on the amino-acid sequence of the protein

    Durability testing at 5 atmospheres of advanced catalysts and catalyst supports for gas turbine engine combustors

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    The durability of CATCOM catalysts and catalyst supports was experimentally demonstrated in a combustion environment under simulated gas turbine engine combustor operating conditions. A test of 1000 hours duration was completed with one catalyst using no. 2 diesel fuel and operating at catalytically-supported thermal combustion conditions. The performance of the catalyst was determined by monitoring emissions throughout the test, and by examining the physical condition of the catalyst core at the conclusion of the test. Tests were performed periodically to determine changes in catalytic activity of the catalyst core. Detailed parametric studies were also run at the beginning and end of the durability test, using no. 2 fuel oil. Initial and final emissions for the 1000 hours test respectively were: unburned hydrocarbons (C3 vppm):0, 146, carbon monoxide (vppm):30, 2420; nitrogen oxides (vppm):5.7, 5.6

    RESULTS OF A FARM AND MARKET SURVEY FOR HMONG SPECIALTY CROP FARMERS IN THE MINNEAPOLIS, ST. PAUL METRO AREA

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    This report is part of a larger project, "Risk Management Education and Farm Management Development Program for Hmong Specialty Crop Farmers in the Minneapolis, St. Paul Metro Area," funded by the Risk Management Agency, U.S. Department of Agriculture. The project was designed to assist Hmong farmers in the Twin Cities area in improving their production and management practices so they are able to increase their economic viability and reduce their exposure to risk. As part of the overall project, 62 Hmong farmers and 69 customers at farmers markets were surveyed to determine the local specialty crop production and market conditions. The findings of these 2 surveys are contained in the report. The median size of the 62 farms surveyed farms was 3 acres. Forty-two percent of those farmers responding reported total farm product sales between 3,000and3,000 and 8,999. Few farmers indicated they were familiar with crop insurance programs. Sixty-eight percent of the 19 farmers responding (or 21% of the 62 surveyed) said they were familiar with multi-peril crop insurance (MPCI). Only 12% of the 50 farmers responding had bought crop insurance in 2002. The most frequently indicated needs for future education programs were production oriented: weed control, insect control, fertilization, and pesticide safety. All of the 69 customers surveyed regularly bought some kind of vegetables or herbs. Over half of the customers bought potatoes, snap beans, peppers, sweet corn, carrots, cucumbers, basil, and winter squash. Eighty-eight percent of customers indicated they typically spend between 10and10 and 29 on vegetables and herbs during each visit to a farmers' market.Crop Production/Industries,

    Inefficiency of classically simulating linear optical quantum computing with Fock-state inputs

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    Aaronson and Arkhipov recently used computational complexity theory to argue that classical computers very likely cannot efficiently simulate linear, multimode, quantum-optical interferometers with arbitrary Fock-state inputs [Aaronson and Arkhipov, Theory Comput. 9, 143 (2013)]. Here we present an elementary argument that utilizes only techniques from quantum optics. We explicitly construct the Hilbert space for such an interferometer and show that its dimension scales exponentially with all the physical resources. We also show in a simple example just how the Schr\"odinger and Heisenberg pictures of quantum theory, while mathematically equivalent, are not in general computationally equivalent. Finally, we conclude our argument by comparing the symmetry requirements of multiparticle bosonic to fermionic interferometers and, using simple physical reasoning, connect the nonsimulatability of the bosonic device to the complexity of computing the permanent of a large matrix.Comment: 7 pages, 1 figure Published in PRA Phys. Rev. A 89, 022328 (2014
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