16,730 research outputs found

    Synthesis and Structures of Co Bis-Trifluoromethylpyrazolate Complexes

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    Reactions of Co(PMe3)(3)Cl or CoCl2 with 3,5-(CF3)(2)-PzNa in hexane give Co(PMe3)(3)(3,5-(CF3)(2)-Pz) (1) and Co(PMe3)(3)(3,5-(CF3)(2)-Pz)(2) (2) respectively (3,5-(CF3)(2)-PzNa = sodium bis-trifluoromethylpyrazolate). Reaction of (3,5-(CF3)(2)-PzH) with Co(PMe3)(4) produces the unusual complex [cis-Co(PMe3)(4)H-2][Co(PMe3)(3,5-( CF3)(2)-Pz)(3)] (3) which formally contains a [Co(III)](+)[Co(II)](-) complex ion pair. Reaction of 3,5-(CF3)(2)-PzLi with an oxygenated suspension of CoCl2 and 3 equivalents of PMe3 gives (3,5-(CF3)(2)-Pz)(2)Co(mu-3,5-(CF3)(2)Pz)(mu-OPMe3)Li(OPMe3)(2) (4), while 2 reacts with LiOH to give [(PMe3)Co(mu-3,5-(CF3)(2)-Pz)(2)(mu(3)-OH)Li](2) (5). Both 2 and 3 react with O-2 in toluene solution to give Co(OPMe3)(2)(3,5-(CF3)(2)-Pz)(2) (6). All compounds have been characterized spectroscopically and by single crystal X-ray diffraction studies.Welch Foundation F-816Petroleum Research Fund 47014-ACSNSF 0741973Chemistr

    Alien Registration- Richard, Joseph A. (Wilton, Franklin County)

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    https://digitalmaine.com/alien_docs/19569/thumbnail.jp

    Data catalog series for space science and applications flight missions. Volume 6: Master index volume

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    The main purpose of the data catalog series is to provide descriptive references to data generated by space science flight missions. The data sets described include all of the actual holdings of the Space Science Data Center (NSSDC), all data sets for which direct contact information is available, and some data collections held and serviced by foreign investigators, NASA, and other U.S. government agencies. This volume contains the Master Index. The following spacecraft are included: Mariner, Pioneer, Pioneer Venus, Venera, Viking, Voyager, and Helios. Separate indexes to the planetary and interplanetary missions are also provided

    Barriers to recovery and recommendations for change: the Pennsylvania Consensus Conference on psychiatry\u27s role.

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    OBJECTIVE: Recovery has emerged over the past decade as a dominant theme in public mental health care. METHODS: The 2006 Pennsylvania Consensus Conference brought together 24 community psychiatrists to explore the barriers they experienced in promoting recovery and their recommendations for change. RESULTS: Twelve barriers were identified and classified into one of three categories: psychiatry knowledge, roles, and training; the need to transform public mental health systems and services; and environmental barriers to opportunity. Participants made 22 recommendations to address these barriers through changes in policies, programs, and psychiatric knowledge and practice. CONCLUSIONS: The recommendations identify areas for change that can be accomplished through individual psychiatrist action and organized group efforts

    \u3cem\u3eRhizobium leguminosarum\u3c/em\u3e CFN42 Genetic Regions Encoding Lipopolysaccharide Structures Essential for Complete Nodule Development on Bean Plants

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    Eight symbiotic mutants defective in lipopolysaccharide (LPS) synthesis were isolated from Rhizobium leguminosarum biovar phaseoli CFN42. These eight strains elicited small white nodules lacking infected cells when inoculated onto bean plants. The mutants had undetectable or greatly diminished amounts of the complete LPS (LPS I), whereas amounts of an LPS lacking the O antigen (LPS II) greatly increased. Apparent LPS bands that migrated between LPS I and LPS II on sodium dodecyl sulfate-polyacrylamide gels were detected in extracts of some of the mutants. The mutant strains were complemented to wild-type LPS I content and antigenicity by DNA from a cosmid library of the wild-type genome. Most of the mutations were clustered in two genetic regions; one mutation was located in a third region. Strains complemented by DNA from two of these regions produced healthy nitrogen-fixing nodules. Strains complemented to wild-type LPS content by the other genetic region induced nodules that exhibited little or no nitrogenase activity, although nodule development was obviously enhanced by the presence of this DNA. The results support the idea that complete LPS structures, in normal amounts, are necessary for infection thread development in bean plants

    Controlling the crystal polymorph by exploiting the time dependence of nucleation rates

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    Most substances can crystallise into two or more different crystal lattices, called polymorphs. Despite this, there are no systems in which we can quantitatively predict the probability of one competing polymorph forming, instead of the other. We address this problem using large scale (hundreds of events) studies of the competing nucleation of the alpha and gamma polymorphs of glycine. In situ Raman spectroscopy is used to identify the polymorph of each crystal. We find that the nucleation kinetics of the two polymorphs is very different. Nucleation of the alpha polymorph starts off slowly but accelerates, while nucleation of the gamma polymorph starts off fast but then slows. We exploit this difference to increase the purity with which we obtain the gamma polymorph by a factor of ten. The statistics of the nucleation of crystals is analogous to that of human mortality, and using a result from medical statistics we show that conventional nucleation data can say nothing about what, if any, are the correlations between competing nucleation processes. Thus we can show that, with data of our form, it is impossible to disentangle the competing nucleation processes. We also find that the growth rate and the shape of a crystal depends on when it nucleated. This is new evidence that nucleation and growth are linked.Comment: 8 pages, plus 17 pages of supplementary materia

    The Universal Cloud and Aerosol Sounding System (UCASS): a low-cost miniature optical particle counter for use in dropsonde or balloon-borne sounding systems

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    © Author(s) 2019. This work is distributed under the Creative Commons Attribution 4.0 License. An earlier version of this work was published in Atmospheric Measurement Techniques Discussions: https://dx.doi.org/10.5194/amt-2019-70.A low-cost miniaturized particle counter has been developed by The University of Hertfordshire (UH) for the measurement of aerosol and droplet concentrations and size distributions. The Universal Cloud and Aerosol Sounding System (UCASS) is an optical particle counter (OPC), which uses wide-angle elastic light scattering for the high-precision sizing of fluid-borne particulates. The UCASS has up to 16 configurable size bins, capable of sizing particles in the range 0.4–40 µm in diameter. Unlike traditional particle counters, the UCASS is an open-geometry system that relies on an external air flow. Therefore, the instrument is suited for use as part of a dropsonde, balloon-borne sounding system, as part of an unmanned aerial vehicle (UAV), or on any measurement platform with a known air flow. Data can be logged autonomously using an on-board SD card, or the device can be interfaced with commercially available meteorological sondes to transmit data in real time. The device has been deployed on various research platforms to take measurements of both droplets and dry aerosol particles. Comparative results with co-located instrumentation in both laboratory and field settings show good agreement for the sizing and counting ability of the UCASS.Peer reviewe
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