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  • 1
    Electronic Resource
    Electronic Resource
    Food Analysis, Determination of Benzoic and Salicylic Acids in Food Products (1955)
    s.l. : American Chemical Society
    Journal of agricultural and food chemistry 3 (1955), S. 964-969 
    Details
    ISSN: 1520-5118
    Source: ACS Legacy Archives
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/jf60057a011
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  • 2
    Electronic Resource
    Electronic Resource
    Pesticide Determination, Chemical Determination of Perthane Residues on Agricultural Crops (1957)
    s.l. : American Chemical Society
    Journal of agricultural and food chemistry 5 (1957), S. 349-350 
    Details
    ISSN: 1520-5118
    Source: ACS Legacy Archives
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/jf60075a002
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  • 3
    Electronic Resource
    Electronic Resource
    Spectrophotometric Titration of Chromium and Vanadium (1955)
    s.l. : American Chemical Society
    Analytical chemistry 27 (1955), S. 1996-1998 
    Details
    ISSN: 1520-6882
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ac60108a044
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  • 4
    Electronic Resource
    Electronic Resource
    Resource translocation in a marine bryozoan: quantification and visualization of 14C and 35S (1995)
    Springer
    Marine biology 122 (1995), S. 439-445 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Colonial marine invertebrates are characterized by their ability to share resources among the modules of a colony. In most colonial groups, but particularly the Bryozoa, the dynamics of resource transport among modules is unknown. We developed radioisotope techniques to visualize and quantify the movement of carbon and sulfur-based compounds within colonies of the marine bryozoan Membranipora membranacea. The research was conducted in 1991 and 1992 in Friday Harbor, Washington, USA. Autoradiography, using X-ray film, was used to visualize the transport of both 14C and 35S, and a liquid scintillation counter was used to quantify transport of metabolites. We were able to localize feeding by introducing 10 μl aliquots of labelled algal cells with a microinjection syringe into a containment ring on the surface of the colony. The labelled cells were consumed by zooids feeding within the ring, but not by those outside. In time-course within the ring, but not by those outside. In time-course experiments, ≃15% of the ingested carbon radioisotope was transported from a source in the center of the colonies to the growing edges over a period of 48 h. Approximately 10% of the sulfur was transported from central to edge regions of colonies over 72 h. Transport of carbon isotope was unidirectional in all experiments, irrespective of whether colonies were fed near the edge or the center. Pulse-chase experiments revealed that up to 46% of the initial 14C radioisotope was lost from the colony to respiration and egestion in the 24 h following ingestion.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00350877
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  • 5
    Electronic Resource
    Electronic Resource
    Water flow and prey capture by three scleractinian corals, Madracis mirabilis, Montastrea cavernosa and Porites porites, in a field enclosure (1998)
    Springer
    Marine biology 131 (1998), S. 347-360 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Scleractinian corals experience a wide range of flow regimes which, coupled with colony morphology, can affect the ability of corals to capture zooplankton and other particulate materials. We used a field enclosure oriented parallel to prevailing oscillatory flow on the forereef at Discovery Bay, Jamaica, to investigate rates of zooplankton capture by corals of varying morphology and polyp size under realistic flow speeds. Experiments were carried out from 1989 to 1992. Particles (Artemia salina cysts) and naturally occurring zooplankton attracted into the enclosures were used as prey for the corals Madracis mirabilis (Duchassaing and Michelotti) (narrow branches, small polyps), Montastrea cavernosa (Linnaeus) (mounding, large polyps), and Porites porites (Pallas) (wide branches, small polyps). This design allowed corals to be used without removing them or their prey from the reef environment, and avoided contact of zooplankton with net surfaces. Flow speed had significant effects on capture rate for cysts (M. mirabilis), total zooplankton (M. mirabilis, M. cavernosa), and non-copepod zooplankton (M. mirabilis). Zooplankton prey capture increased with prey concentration for M. mirabilis and M. cavernosa, over a broad range of concentrations, indicating that saturation of the feeding response had not occurred until prey density was over 104 items m−3, a concentration at least an order of magnitude greater than the normal range of reef zooplankton concentrations. Location of cyst capture on coral surfaces was not uniform; for M. cavernosa, sides and tops of mounds captured most particles, and for P. porites, capture was greatest near branch tops, but was close to uniform for M. mirabilis branches in all flow conditions. The present study confirms laboratory flume results, and field results for other species, suggesting that many coral species experience particle flux and encounter rate limitations at low flow speeds, decreasing potential zooplankton capture rates.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002270050328
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  • 6
    Electronic Resource
    Electronic Resource
    High-resolution infrared diode laser spectroscopy of (CO2)3: Vibrationally averaged structures, resonant dipole vibrational shifts, and tests of CO2–CO2 pair potentials (1995)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 103 (1995), S. 7685-7699 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: High-resolution infrared spectra of (CO2)3 formed in a slit jet supersonic expansion are obtained via direct absorption of a tunable diode laser in the ν3 asymmetric stretch region of CO2. Over 100 distinct transitions are recorded in the trimer spectrum, which can be modeled as a perpendicular band of a planar symmetric top with C3h symmetry and no observable tunneling splittings. Results from the spectroscopic fit indicate that the complex is vibrationally averaged planar, with a carbon–carbon atom separation of RCC=4.0376(2) A(ring). An analysis of the vibrational blue shift for (CO2)3 of 2.5755(2) cm−1 via a resonant dipole–dipole interaction model yields an angular orientation for each CO2 axis of β=33.8(5)° away from a line tangent to the vertex and parallel to the opposite side of the equilateral triangle connecting the centers of mass of each CO2 monomer. Several model CO2–CO2 interaction potentials are tested against the vibrationally averaged structural parameters for (CO2)3. In particular, the potential of Murthy et al. [Mol. Phys. 50, 531 (1983)] reproduces RCC for the complex, but similar to all potentials tested, does not accurately predict the angular orientation β of the monomers within the trimer. Lastly, spectral evidence and model predictions suggest that there is an asymmetric top isomer of the trimer that is energetically comparable to the observed cyclic isomer. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.470291
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  • 7
    Electronic Resource
    Electronic Resource
    Aligning symmetric and asymmetric top molecules via single photon excitation (1997)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 107 (1997), S. 7138-7147 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The theory developed by Zare [Ber. Bunsenges. Phys. Chem. 86, 422 (1982)] for using electric-dipole-allowed photoexcitation with linearly polarized light to align linear and symmetric top molecules via parallel transitions is extended to include perpendicular transitions, as well as the alignment of asymmetric tops via a-, b-, or c-type transitions. Analytical expressions for the spatial distribution of a symmetric top figure axis following a parallel or perpendicular transition are presented. A prescription is developed for determining the spatial distribution of each principal axis of an asymmetric or symmetric top following parallel or perpendicular type transitions. The degree of alignment obtainable via photoexcitation for symmetric and asymmetric tops is discussed, with the somewhat surprising result that all three principal axes of an asymmetric top can be highly aligned via photoexcitation. A simple computer program for calculating the degree of alignment of each principal axis of a symmetric or asymmetric top following an a-, b-, or c-type transition is described and made available. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.474955
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  • 8
    Electronic Resource
    Electronic Resource
    Geometric isomerism in clusters: High resolution infrared spectroscopy of a noncyclic CO2 trimer (1996)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 105 (1996), S. 10210-10223 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: High resolution infrared spectra of a previously unidentified noncyclic isomer of (CO2)3 have been obtained via direct absorption of a 4.3 μm diode laser in a slit jet supersonic expansion. Two vibrational bands (labeled νI and νIII) are observed, corresponding to the two most infrared active linear combinations of the three constituent CO2 monomer asymmetric stretches: νI is redshifted −5.85 cm−1 from the monomer vibrational origin and is predominately a c-type band of an asymmetric top, while νIII is blueshifted +3.58 cm−1 and is predominately an a-type band. Transitions with Ka+Kc=odd (even) in the ground (excited) state are explicitly absent from the spectra due to the zero nuclear spin of CO2; this rigorously establishes that the noncyclic isomer has a C2 symmetry axis. The vibrational shifts and relative intensities of the bands are interpreted via a resonant dipole interaction model between the high-frequency stretches of the CO2 monomers. Rotational constants are determined by fits of transition frequencies to an asymmetric top Hamiltonian. These results are used to determine vibrationally averaged structural parameters for the complex, which is found to be stacked asymmetric but with C2 symmetry about the b inertial axis. The structural parameters are then used to test several trial CO2–CO2 interaction potentials. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.472930
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  • 9
    Electronic Resource
    Electronic Resource
    Scattering dynamics in HF+He, Ne, and Ar: State-to-state cross sections, Dopplerimetry, and alignment measurement via direct infrared laser absorption in crossed supersonic jets (1997)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 106 (1997), S. 2248-2264 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Absolute state-to-state cross sections are reported for rotationally inelastic scattering in crossed jets of HF with He, Ne, and Ar at mean center-of-mass collision energies of 480, 390, and 350 cm−1, respectively. HF seeded in Ar diluent gas is cooled into the J=0 ground rotational state in a pulsed supersonic expansion, followed by single collision rotational excitation with rare gas atoms from a second pulsed supersonic jet. The column-integrated densities of HF in both the initial and final scattering states are probed in the jet intersection region via direct absorption of light from a narrow bandwidth (0.0001 cm−1), continuously tunable, color center laser. Total inelastic cross sections for collisional loss out of J=0 and collisional excitation into J〉0 states are determined in absolute units from the dependence of infrared absorption signals on collider gas concentration. Full close coupling scattering calculations are performed on several ab initio and empirical potential energy surfaces for each of the three HF+rare gas systems. Agreement for He+HF and Ar+HF integral cross sections is remarkably good, but significant discrepancies are noted for the less accurately determined Ne+HF surface. Photoelastic polarization modulation of the IR laser is used to probe for rotational alignment in the scattered HF flux; the measurements set an upper polarizance limit for collisionally populated J=1 HF molecules [probed on P(1)] of |P|〈2%. High resolution IR laser Dopplerimetry reveals velocity structure in the collisionally excited J=1 Doppler profiles, which is in excellent qualitative agreement with theoretical predictions of rainbow features in the J=1←0 state-to-state differential cross section. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.473787
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  • 10
    Electronic Resource
    Electronic Resource
    High-resolution diode laser study of H2–H2O van der Waals complexes: H2O as proton acceptor and the role of large amplitude motion (1999)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 110 (1999), S. 156-167 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Three high-resolution rovibrational bands of ortho H2 with both para and ortho H2O are observed in a slit supersonic expansion, based on direct absorption of a tunable diode laser in the ν2 bend region of H2O near 1600 cm−1. Complexes containing para H2O are responsible for a Σ←Σ type band associated with intramolecular bending excitation of H2O, while complexes containing ortho H2O exhibit two bands associated with (i) the intramolecular HOH bend (Π←Π) and (ii) an inter+intramolecular combination band (Σ←Π) corresponding to simultaneous HOH bend plus internal rotor excitation. From high-resolution line broadening studies, each upper state has a different vibrational predissociation lifetime; for bend excited para H2O complexes it is 5.1(14) nsec, while for the bend excited state and bend+internal rotor combination state of ortho H2O, it is 2.53(14) and 1.85(33) nsec, respectively. Analysis of the spectra supplemented by 2D quantum calculations indicate large amplitude, slightly hindered internal rotation of the H2O subunit in the complex. Nevertheless, the internal rotor splittings yield potential parameters that suggest ortho H2–H2O is best described with the H2 predominantly pointing towards the O atom in a H2O proton acceptor geometry. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.478091
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