Chemistry Commons^™

Tunable Picosecond Infrared Laser System Based On Parametric Amplification In Ktp With A Ti:Sapphire Amplifier, D. E. Gragson, D. S. Alavi, G. L. Richmond

Chemistry and Biochemistry

A picosecond laser system that will generate high-power tunable IR pulses with bandwidths suitable for spectroscopic applications is discussed. The system is based on white-light continuum generation in ethylene glycol and optical parametric amplification in potassium titanyl phosphate. The nonlinear-optical processes are driven by a regeneratively amplified Ti:sapphire laser that produces 1.7-ps pulses at a repetition rate of 1 kHz. Energies as high as 40 and 12 µJ have been achieved over the signal (1.02–1.16-µm) and idler (2.6–3.7-µm) tuning ranges, respectively. The IR beam temporal and spatial characteristics are also presented.

Three-Phase Intersection Points In Monolayers, John P. Hagen, Harden M. Mcconnell

Chemistry and Biochemistry

Some phospholipid/dihydrocholesterol Langmuir monolayers form coexisting liquid phases. Gas domains form at the interface between the phospholipid-rich and dihydrocholesterol-rich liquid phases when these monolayers undergo expansion to low surface pressure. Analysis of the domain shapes thus formed yields the relative line tensions of the gas/phospholipid, gas/dihydrocholesterol, and phospholipid/dihydrocholesterol phase interfaces.

Nutrient Limitation In A Southwestern Desert Reservoir: Eutrophication Of Las Vegas Bay, Lake Mead, Nevada, Davine M. Lieberman

Publications (WR)

Algal bioassay tests were conducted with Selenastrum capricornutum and natural algae on inner Las Vegas Bay, Lake Mead, Nevada, from December 1992 through September 1993, to identify any nutrient limitation in an area of the reservoir that has experienced problems associated with severe nutrient enrichment. Three areas were sampled based on a gradient of water quality conditions that existed in Las Vegas Bay (LVB). Disodium ethylenedinitrilotetraacetate (EDTA) significantly stimulated algal growth compared to non-EDTA treatment. Algal bioassays indicated that phosphorus (P) was the primary limiting nutrient at all stations for most of the test dates. Chl a response with EDTA …

Environments Of The Four Tryptophans In The Extracellular Domain Of Human Tissue Factor: Comparison Of Results From Absorption And Fluorescence Difference Spectra Of Tryptophan Replacement Mutants With The Crystal Structure Of The Wild-Type Protein, C. A. Hasselbacher, E. Rusinova, R. Rusinova, R. A. Kohanski, W. Lam, A. Guha, J. Du, T. C. Lin, I. Polikarpov, C. W. G. Boys, Y. Nemerson, W. H. Konigsberg, J. B. A. Ross

Chemistry and Biochemistry Faculty Publications

The local environments of the four tryptophan residues of the extracellular domain of human tissue factor (sTF) were assessed from difference absorption and fluorescence spectra. The difference spectra were derived by subtracting spectra from single Trp-to-Phe or Trp-to-Tyr replacement mutants from the corresponding spectrum of the wild-type protein. Each of the mutants was capable of enhancing the proteolytic activity of factor Vila showing that the mutations did not introduce major structural changes, although the mutants were more susceptible to denaturation by guanidinium chloride. The difference spectra indicate that the Trp residues are buried to different extents within the protein matrix. …

Structural Characterization Of A Novel Inhibitor Of Hiv Reverse Transcriptase (Hiv Rt), Greggory Jon Woitte

Chemistry & Biochemistry Theses & Dissertations

Human immunodeficiency virus (HIV) infections have become a leading cause of death among young people in the United States today. As the number of HIV infections increases, so too does the cost of treatment. Together, these numbers have prompted an increase in the development of pharmaceutical interventions. HIV reverse transcriptase (HIV RT) has become a suitable target for drug therapy because it is the sole enzyme responsible for HIV replication.

Fucoidan, a sulfated polysaccharide isolated from the brown algae Fucus vesiculosus, has been shown to block a variety of cell adhesion related events including metastasis. In addition, fucoidan has also …

Ground Breaking Ceremony For The Marine Chemistry & Toxicology Building, Virginia Institute Of Marine Science, School Of Marine Science, College Of William And Mary

Miscellaneous

Ceremony held April 13, 1995. Program of the event.

New Optical Cell Design For Laser Flash Photolysis Studies In Supercritical Fluids, Steven R. Goates, Milton L. Lee, Qin Ji, Edward M. Eyring, Rudi Van Eldik, Kedika Bal Reddy

Faculty Publications

A high-pressure optical cell has been designed that achieves an effective separation between the chemical sample and the pressurizing medium and system. This design limits possible sample contamination and catalytic effects under supercritical fluid sample conditions. Laser flash photolysis experiments were carried out on molybdenum hexacarbonyl dissolved in supercritical CO2. The thermal ring closure reaction of the species Mo(CO)5L, where L is 2,2- bipyridine was found to proceed at rates comparable to those measured previously in liquid benzene or toluene. Much larger activation volumes were found for the reaction in supercritical CO2 than in liquid toluene.