Microwave spectrum, structure, barrier to internal rotation, dipole moment, and deuterium quadupole coupling constants of the ethylene–sulfur dioxide complex

The microwave spectra of the complex between ethylene and sulfur dioxide and nine of its isotopic species have been observed in a Fourier transform microwave spectrometer. The spectra exhibit a and c dipole selection rules; transitions of the normal species and several of the isotopically substituted species occur as tunneling doublets. The complex has a stacked structure with Cs symmetry; the C2H4 and SO2 moieties both straddle the mirror plane with the C2 axis of SO2 crossed at 90 ° to the carbon–carbon bond axis (i.e., only the S atom lies in the symmetry plane). The distance between the centers of mass (Rcm) of C2H4 and SO2 is 3.504(1) Å and the deviation of their planes from perpendicular to Rcm is 21(2) ° and 12(2) °, respectively. The tunneling splittings arise from a rotation of the ethylene subunit in its molecular plane. The barrier to internal rotation is 30(2) cm−1. The dipole moment of the complex is 1.650(3)D. The deuterium nuclear quadrupole coupling constants for C2H3D⋅SO2 are χaa=−0.119(1) MHz, χbb=0.010(1) MHz, and χcc=0.109(1) MHz. The binding energy is estimated to be 490 cm−1 from the pseudo‐diatomic approximation. A distributed multipole electrostatic model is explored to rationalize the structure and binding energies.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70892/2/JCPSA6-93-10-7030-1.pd

Prehospital Intubations Are Associated With Elevated Cuff Pressures: A Cross-Sectional Study Characterizing ETT Cuff Pressures at the UMMMC University Emergency Department

Abstract will be available upon expiration of embargo

The structures and dipole moments of Ar–PF3 and Kr–PF3

The complexes of PF3 with Ar and Kr, were studied by Fourier transform microwave spectroscopy. The force constants and amplitudes of vibration for the van der Waals modes of the complexes and the average moments of inertia and structural parameters were estimated from the centrifugal distortion constants. The distance (Rc.m. )ave between the rare‐gas atom and the center of mass of PF3 is 3.959 Å for the Ar complex and 4.077 Å for Kr while the angle (θc.m. )ave between the Rc.m. vector and the C3 axis of the PF3 is 69.30° and 67.25°, respectively. The dipole moments of both complexes and of free PF3 were determined. The induced dipole components estimated for the rare gas using electric fields from ab initio calculations of PF3 agree with the experimental values for a conformation with the rare gas over a PF2 face. The PF2 face conformation is also consistent with the observed and ab initio estimates of the 83 Kr nuclear quadrupole coupling constant for the 83 Kr–PF3 species.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70747/2/JCPSA6-90-12-6949-1.pd

The microwave spectrum and structure of krypton--phosphorus trifluoride

The rotational spectrum of the weak complex between krypton and phosphorus trifluoride has been observed using a Fourier transform microwave spectrometer with a pulsed supersonic nozzle molecular beam source. The complex is an asymmetric top. The distance rcm between the krypton atom and the center of mass of the PF3 molecule is 4.0722 A and the angle between the rcm vector and the C3 axis of the PF3 is 68.25[deg]. Based on the centrifugal distortion constant DJ and a pseudodiatomic model, the binding energy of the complex is estimated to be 218 cm-1.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/27096/1/0000087.pd

The benzene-SO2 and pyridine-SO2 complexes

The benzene-SO2 and pyridine-SO2 complexes have been observed for the first time using Fourier transform microwave spectroscopy. The complexes have different geometries. In benzene-SO2, the two planar species are stacked one above the other. In pyridine-SO2, the pyridine plane rotates by 70[deg], so that it is more nearly perpendicular to the SO2 plane.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/27846/1/0000257.pd

Fragmentative and stereochemical isomerization probes for homolytic carbon to phosphorus bond scission catalyzed by bacterial carbon-phosphorus lyase

Three bacterial strains, Agrobacterium radiobacter, Klebsiella oxytoca, and Kluyvera ascorbata, isolated by enrichment culture for carbon to phosphorus bond cleavage ability, were analyzed for the mode of C---P bond fission. The cleavage of alkyl phosphonic acids to alkanes and inorganic phosphates proceeded both aerobically and anaerobically, and growth on trideuteromethylphosphonic acid yielded trideuteromethane as product. These data indicate that functionalization of the organic moiety does not precede carbon to phosphorus bond cleavage. As probes for radical intermediates, cyclopropylmethylphosphonic acid and cis-1,2-dideutero-1-propenylphosphonic acid were used in growth experiments and the gaseous hydrocarbon products were examined. With the cyclopropylmethylphosphonic acid probe, all three bacteria produced methylcyclopropane, but only K. oxytoca and K. ascorbata also generated the acyclic olefin 1-butene, and then only in very low quantity (0.6 and 0.3% versus methylcyclopropane, respectively). With the propenylphosphonic acid probe, cis-1,2-dideuteropropene was formed with greater than 98% retention of configuration with each bacterial strain. Only for K. oxytoca was the alternate product, in this case trans-1,2-dideuteropropene, clearly detected at 1.5%. Thus, C---P bond fission may yield radical intermediates that are trapped efficiently at the enzyme active site or, alternatively, homolysis of the C---P bond may occur as a minor reaction pathway.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/26489/1/0000025.pd

Why Moral Expertise Needs Moral Theory

Discussions of the nature or possibility of moral expertise have largely proceeded in atheoretical terms, with little attention paid to whether moral expertise depends on theoretical knowledge of morality. Here I argue that moral expertise is more theory-dependent than is commonly recognized: Moral expertise consists, at least in part, in knowledge of the correct or best moral theory, and second, that knowledge of moral theory is essential to moral experts dispensing expert counsel to non-experts. Moral experts would not be moral experts absent knowledge of moral theory, nor could they play the testimonial role we would expect them to play in moral inquiry and deliberation absent such knowledg

Further Characterisation of the Molecular Signature of Quiescent and Activated Mouse Muscle Satellite Cells

Satellite cells are the resident stem cells of adult skeletal muscle. To date though, there is a paucity of native markers that can be used to easily identify quiescent satellite cells, with Pax7 probably being the best that is currently available. Here we have further characterized a number of recently described satellite cell markers, and also describe novel ones. Caveolin-1, integrin α7 and the calcitonin receptor proved reliable markers for quiescent satellite cells, being expressed by all satellite cells identified with Pax7. These three markers remained expressed as satellite cells were activated and underwent proliferation. The nuclear envelope proteins lamin A/C and emerin, mutations in which underlie Emery-Dreifuss muscular dystrophy, were also expressed in both quiescent and proliferating satellite cells. Conversely, Jagged-1, a Notch ligand, was not expressed in quiescent satellite cells but was induced upon activation. These findings further contribute to defining the molecular signature of muscle satellite cells

Short-Term Exposure of Multipotent Stromal Cells to Low Oxygen Increases Their Expression of CX3CR1 and CXCR4 and Their Engraftment In Vivo

The ability of stem/progenitor cells to migrate and engraft into host tissues is key to their potential use in gene and cell therapy. Among the cells of interest are the adherent cells from bone marrow, referred to as mesenchymal stem cells or multipotent stromal cells (MSC). Since the bone marrow environment is hypoxic, with oxygen tensions ranging from 1% to 7%, we decided to test whether hypoxia can upregulate chemokine receptors and enhance the ability of human MSCs to engraft in vivo. Short-term exposure of MSCs to 1% oxygen increased expression of the chemokine receptors CX3CR1and CXCR4, both as mRNA and as protein. After 1-day exposure to low oxygen, MSCs increased in vitro migration in response to the fractalkine and SDF-1α in a dose dependent manner. Blocking antibodies for the chemokine receptors significantly decreased the migration. Xenotypic grafting into early chick embryos demonstrated cells from hypoxic cultures engrafted more efficiently than cells from normoxic cultures and generated a variety of cell types in host tissues. The results suggest that short-term culture of MSCs under hypoxic conditions may provide a general method of enhancing their engraftment in vivo into a variety of tissues